This file is indexed.

/usr/share/doc/pythia8-doc/html/ParticleDataScheme.html is in pythia8-doc-html 8.1.86-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
<html>
<head>
<title>The Particle Data Scheme</title>
<link rel="stylesheet" type="text/css" href="pythia.css"/>
<link rel="shortcut icon" href="pythia32.gif"/>
</head>
<body>
 
<h2>The Particle Data Scheme</h2> 
 
The particle data scheme may take somewhat longer to understand than 
the settings one. In particular the set of methods to access information 
is rather more varied, to allow better functionality for advanced usage. 
However, PYTHIA does come with a sensible default set of particle 
properties and decay tables. Thus there is no need to learn any of the 
methods on this page to get going. Only when you perceive a specific need 
does it make sense to learn the basics. 
 
<p/> 
The central section on this page is the Operation one. The preceding 
sections are there mainly to introduce the basic structure and the set 
of properties that can be accessed. The subsequent sections provide a 
complete listing of the existing public methods, which most users 
probably will have little interaction with. 
 
<h3>Databases</h3> 
 
The management of particle data is based on three classes: 
<ul> 
<li><code>ParticleData</code>, which is the top-level class, with 
methods that can be used to interrogate all particle data. It contains 
a map of PDG particle identity numbers [<a href="Bibliography.html" target="page">Yao06</a>] onto the relevant 
<code>ParticleDataEntry</code> objects,</li> 
<li><code>ParticleDataEntry</code>, which stores the relevant information 
on an individual particle species, and</li> 
<li><code>DecayChannel</code>, which stores info on one particular decay 
mode of a particle.</li> 
 
</ul> 
The objects of these classes together form a database that is 
continuously being used as the program has to assign particle masses, 
select decay modes, etc. 
 
<p/> 
Each <code>Pythia</code> object has a public member 
<code>particleData</code> of the <code>ParticleData</code> class. 
Therefore you access the particle data methods as 
<code>pythia.particleData.command(argument)</code>, 
assuming that <code>pythia</code> is an instance of the 
<code>Pythia</code> class. Further, for some of the most frequent user 
tasks, <code>Pythia</code> methods have been defined, so that 
<code>pythia.command(argument)</code> 
would work, see further below. 
 
<p/> 
A fundamental difference between the particle data classes and the 
settings ones is that the former are accessed regularly during the 
event generation process, as a new particle is produced and its mass 
need to be set, e.g., while the latter are mainly/only used 
at the initialization stage. Nevertheless, it is not a good idea to 
change data in either of them in mid-run, since this may lead to 
inconsistencies. 
 
<h3>Stored properties for particles</h3> 
 
The main properties stored for each particle are as follows. 
Different ways to set and get these properties will be described 
further down. 
 
<ul> 
 
<li><code>name</code>: a character string with the name of the 
particle. Particle and antiparticle names are stored separately, 
with <code>void</code> returned when no antiparticle exists.</li> 
 
<li><code>spinType</code>: the spin type, of the form <i>2 s + 1</i>, 
with special code 0 for entries of unknown or indeterminate spin.</li> 
 
<li><code>chargeType</code>: three times the charge (to make it an 
integer).</li> 
 
<li><code>colType</code>: the colour type, with 0 uncoloured, 1 triplet, 
-1 antitriplet and 2 octet. (A preliminary implementation of colour 
  sextets, available since version 8.150, further uses 3 for a sextet 
  and -3 for an antisextet.) </li> 
 
<li><code>m0</code>: the nominal mass <i>m_0</i> (in GeV).</li> 
 
<li><code>mWidth</code>: the width <i>Gamma</i> of the Breit-Wigner 
distribution (in GeV).</li> 
 
<li><code>mMin</code>: the lower limit of the allowed mass range 
generated by the Breit-Wigner (in GeV). Has no meaning for particles 
without width, and would typically be 0 there.</li> 
 
<li><code>mMax</code>: the upper limit of the allowed mass range 
generated by the Breit-Wigner (in GeV). If <i>mMax &lt; mMin</i> then 
no upper limit is imposed. Has no meaning for particles without width, 
and would typically be 0 there.</li> 
 
<li><code>tau0</code>: the nominal proper lifetime <i>tau_0</i> 
(in mm/c).</li> 
 
<li><code>isResonance</code>: a flag telling whether a particle species 
is considered as a resonance or not. Here 
<a href="ResonanceDecays.html" target="page">"resonance"</a> is used as shorthand 
for any massive particle where the decay process should be counted as part 
of the hard process itself, and thus be performed before showers and other 
event aspects are added. Restrictions on allowed decay channels is also 
directly reflected in the cross section of simulated processes, while 
those of normal hadrons and other light particles are not. 
In practice, it is reserved for states above the <i>b bbar</i> 
bound systems in mass, i.e. for <i>W, Z, t</i>, Higgs states, 
supersymmetric states and (most?) other states in any new theory. 
All particles with <code>m0</code> above 20 GeV are by default 
initialized to be considered as resonances.</li> 
 
<li><code>mayDecay</code>: a flag telling whether a particle species 
may decay or not, offering the main user switch. Whether a given particle 
of this kind then actually will decay also depends on it having allowed 
decay channels, and on other flags for 
<a href="ParticleDecays.html" target="page">particle decays</a> 
(or <a href="ResonanceDecays.html" target="page">resonance decays</a>). 
All particles with <code>tau0</code> below 1000 mm are 
by default initialized to allow decays.</li> 
 
<li><code>doExternalDecays</code>: a flag telling whether a particle 
should be handled by an external decay package or not, with the latter 
default. Can be manipulated as described on this page, but should 
normally not be. Instead the 
<code><a href="ExternalDecays.html" target="page">Pythia::decayPtr(...)</a></code> 
method should be provided with the list of relevant particles.</li> 
 
<li><code>isVisible</code>: a flag telling whether a particle species 
is to be considered as visible in a detector or not, as used e.g. in 
analysis routines. By default this includes neutrinos and a few BSM 
particles (gravitino, sneutrinos, neutralinos) that have neither strong 
nor electromagnetic charge, and are not made up of constituents that 
have it. The value of this flag is only relevant if a particle is 
long-lived enough actually to make it to a detector.</li> 
 
<li><code>doForceWidth</code>: a flag applicable only for resonances 
(see <code>isResonance</code> above), whereby it is possible to force 
resonances to retain their assigned width, whatever that is, see 
<a href="ResonanceDecays.html" target="page">Resonance Decays</a> for details.</li> 
 
</ul> 
 
<h3>Stored properties for decays</h3> 
 
An unstable particle has a decay table consisting of one or more 
decay channel. The following properties are stored for each such channel. 
Again different ways to set and get these properties will be described 
further down. 
<ul> 
 
<li><code>onMode</code>: integer code for use or not of channel,<br/> 
0 if a channel is off,<br/> 
1 if on,<br/> 
2 if on for a particle but off for an antiparticle,<br/> 
3 if on for an antiparticle but off for a particle.<br/> 
If a particle is its own antiparticle then 2 is on and 3 off 
but, of course, for such particles it is much simpler and safer 
to use only 1 and 0.<br/> 
The 2 and 3 options can be used e.g. to encode CP violation in 
B decays, or to let the <i>W</i>'s in a <i>q qbar &rarr; W^+ W^-</i> 
process decay in different channels. </li> 
 
<li><code>bRatio</code>: the branching ratio of the channel 
(with some reservations for resonances, see <code>meMode</code> 
below).</li> 
 
<li><code>meMode</code>: the mode of processing this channel, possibly 
with matrix elements; see the 
<a href="ParticleDecays.html" target="page">particle decays</a> and 
<a href="ResonanceDecays.html" target="page">resonance decays</a> 
descriptions for the list of possibilities. 
Notably the default code 0 for a particle means pure phase space 
decays according to the given branching ratios, while for a resonance 
it means that code exists for the dynamic calculations of partial 
widths and thereby branching ratios as a function of the resonance mass 
(which is done e.g. at initialization based on the mass set by the user). 
Then codes 1 - 99 are reserved for various matrix-element-improved 
ordinary particle decays, and 100 - 103 for resonances where the 
partial width of a given channel is calculated from the total width 
and the stored branching ratio. Thus, to enforce a new branching ratio 
for a resonance channel (with its own partial-width calculation code) 
it is not sufficient only to change the <code>bRatio</code> but also 
to set e.g. <code>meMode = 100</code>. </li> 
 
<li><code>multiplicity</code>: the number of decay products of the 
channel. Can be at most 8.</li> 
 
<li><code>product(i)</code>: the identity code of the decay products, 
where <code>i</code> runs between <code>0</code> and 
<code>multiplicity - 1</code>. Trailing positions are filled with 0. 
</li> 
 
</ul> 
 
<h3>Operation</h3> 
 
The normal flow of the particle data operations is: 
 
<ol> 
 
<li> 
When a <code>Pythia</code> object <code>pythia</code> is created, the 
<code>pythia.particleData</code> member is asked to scan the 
<code>ParticleData.xml</code> file. 
 
<p/> 
All lines beginning with <code>&lt;particle</code> are scanned for 
information on a particle species, and all lines beginning with 
<code>&lt;channel</code> are assumed to contain a decay channel of the 
enclosing particle. In both cases XML syntax is used, with attributes 
used to identify the stored properties, and with omitted properties 
defaulting back to 0 where meaningful. The particle and channel 
information may be split over several lines, up to the &gt; endtoken. 
The format of a <code>&lt;particle</code> tag is: 
<pre> 
    &lt;particle id="..." name="..." antiName="..." spinType="..." chargeType="..." colType="..." 
       m0="..." mWidth="..." mMin="..." mMax="..." tau0="..."&gt; 
    &lt;/particle&gt; 
</pre> 
where the fields are the properties already introduced above. 
Note that <code>isResonance</code>, <code>mayDecay</code>, 
<code>doExternalDecay</code>, <code>isVisible</code> and 
<code>doForceWidth</code> are not set here, but are provided with 
default values by the rules described above. Once initialized, also 
these latter properties can be changed, see below.<br/> 
 
The format of  a <code>&lt;channel></code> tag is: 
<pre> 
    &lt;channel onMode="..." bRatio="..." meMode="..." products="..." /&gt; 
</pre> 
again see properties above. The products are given as a blank-separated 
list of <code>id</code> codes. 
<br/><b>Important</b>: the values in the <code>.xml</code> file should not 
be changed, except by the PYTHIA authors. Any changes should be done 
with the help of the methods described below. 
</li> 
 
<li> <p/> 
Between the creation of the <code>Pythia</code> object and the 
<code>init</code> call for it, you may use the methods of the 
<code>ParticleData</code> class to modify some of the default values. 
Several different approaches can be chosen for this. 
 
<p/> 
a) Inside your main program you can directly set values with 
<pre> 
    pythia.readString(string); 
</pre> 
where both the variable name and the value are contained inside 
the character string, separated by blanks and/or a =, e.g. 
<pre> 
    pythia.readString("111:mayDecay = off"); 
</pre> 
switches off the decays of the <i>pi^0</i>.<br/> 
 
The particle id (> 0) and the property to be changed must be given, 
separated by a colon.<br/> 
 
The allowed properties are: <code>name</code>, <code>antiName</code>, 
<code>spinType</code>, <code>chargeType</code>, <code>colType</code>, 
<code>m0</code>, <code>mWidth</code>, <code>mMin</code>, 
<code>mMax</code>, <code>tau0</code>, <code>isResonance</code>, 
<code>mayDecay</code>, <code>doExternalDecay</code>, 
<code>isVisible</code> and <code>doForceWidth</code>. All of these 
names are case-insensitive. Names that do not match an existing 
variable are ignored.<br/> 
 
Strings beginning with a non-alphanumeric character, like # or !, 
are assumed to be comments and are not processed at all. For 
<code>bool</code> values, the following notation may be used 
interchangeably: <code>true = on = yes = ok = 1</code>, while everything 
else gives <code>false</code> (including but not limited to 
<code>false</code>, <code>off</code>, <code>no</code> and 
<code>0</code>). 
 
<p/> 
Particle data often comes in sets of closely related information. 
Therefore some properties expect the value to consist of several 
numbers. These can then be separated by blanks (or by commas). 
A simple example is <code>names</code>, which expects both the 
name and antiname to be given. A more interesting one is the 
<code>all</code> property, 
<pre> 
    id:all = name antiName spinType chargeType colType m0 mWidth mMin mMax tau0 
</pre> 
where all the current information on the particle itself is replaced, 
but any decay channels are kept unchanged. Using <code>new</code> instead 
of <code>all</code> also removes any previous decay channels. 
If the string contains fewer fields than expected the trailing 
properties are set to vanish ("void", 0 or 0.). Note that such a 
truncated string should not be followed by a comment, since this 
comment would then be read in as if it contained the missing properties. 
The truncation can be done anywhere, specifically a string with only 
<code>id:new</code> defines a new "empty" particle. 
As before, <code>isResonance</code>, <code>mayDecay</code>, 
<code>doExternalDecay</code>, <code>isVisible</code> and 
<code>doForceWidth</code> are (re)set to their default values, and 
would have to be changed separately if required. 
 
<p/> 
A further command is <code>rescaleBR</code>, which rescales each of the 
existing branching ratios with a common factor, such that their new 
sum is the provided value. This may be a first step towards adding 
new decay channels, see further below. 
 
<p/> 
Alternatively the <code>id</code> code may be followed by another integer, 
which then gives the decay channel number. This then has to be 
followed by the property specific to this channel, either 
<code>onMode</code>, <code>bRatio</code>, <code>meMode</code> or 
<code>products</code>. In the latter case all the products of 
the channel should be given: 
<pre> 
    id:channel:products =  product1 product2 .... 
</pre> 
The line will be scanned until the end of the line, or until a 
non-number word is encountered, or until the maximum allowed number 
of eight products is encountered, whichever happens first. (Thus the 
multiplicity of a decay channel need not be input; it is automatically 
calculated from the products list.) It is also possible to replace all 
the properties of a channel in a similar way: 
<pre> 
    id:channel:all = onMode bRatio meMode product1 product2 .... 
</pre> 
To add a new channel at the end, use 
<pre> 
    id:addChannel = onMode bRatio meMode product1 product2 .... 
</pre> 
 
<p/> 
It is currently not possible to remove a channel selectively, but 
setting its branching ratio vanishing is as effective. If you want to 
remove all existing channels and force decays into one new channel 
you can use 
<pre> 
    id:oneChannel = onMode bRatio meMode product1 product2 .... 
</pre> 
 A first <code>oneChannel</code> command could be followed by 
several subsequent <code>addChannel</code> ones, to build 
up a completely new decay table for an existing particle. 
 
<p/> 
When adding new channels or changing branching ratios in general, 
note that, once a particle is to be decayed, the sum of branching 
ratios is always rescaled to unity. Beforehand, <code>rescaleBR</code> 
may be used to rescale an existing branching ratio by the given factor. 
 
<p/> 
There are a few commands that will study all the decay channels of the 
given particle, to switch them on or off as desired. The 
<pre> 
    id:onMode = onMode 
</pre> 
will set the <code>onMode</code> property of all channels to the 
desired value. The 
<pre> 
    id:offIfAny   = product1 product2 .... 
    id:onIfAny    = product1 product2 .... 
    id:onPosIfAny = product1 product2 .... 
    id:onNegIfAny = product1 product2 .... 
</pre> 
will set the <code>onMode</code> 0, 1, 2 or 3, respectively, for all 
channels which contain any of the enumerated products, where the matching 
to these products is done without distinction of particles and 
antiparticles. Note that "<code>Pos</code>" and "<code>Neg</code>" 
are slightly misleading since it refers to the particle and antiparticle 
of the <code>id</code> species rather than charge, but should still be 
simpler to remember and understand than alternative notations. 
Correspondingly 
<pre> 
    id:offIfAll   = product1 product2 .... 
    id:onIfAll    = product1 product2 .... 
    id:onPosIfAll = product1 product2 .... 
    id:onNegIfAll = product1 product2 .... 
</pre> 
will set the <code>onMode</code> 0, 1, 2 or 3, respectively, for all 
channels which contain all of the enumerated products, again without 
distinction of particles and antiparticles. If the same product appears 
twice in the list it must also appear twice in the decay channel, and 
so on. The decay channel is allowed to contain further particles, 
beyond the product list. By contrast, 
<pre> 
    id:offIfMatch   = product1 product2 .... 
    id:onIfMatch    = product1 product2 .... 
    id:onPosIfMatch = product1 product2 .... 
    id:onPosIfMatch = product1 product2 .... 
</pre> 
requires the decay-channel multiplicity to agree with that of the product 
list, but otherwise works as the <code>onIfAll/offIfAll</code> methods. 
 
<p/> 
Note that the action of several of the commands depends on the order 
in which they are executed, as one would logically expect. For instance, 
<code>id:oneChannel</code> removes all decay channels of <code>id</code> 
and thus all previous changes in this decay table, while subsequent 
additions or changes would still take effect. Another example would be that 
<code>23:onMode = off</code> followed by <code>23:onIfAny = 1 2 3 4 5</code> 
would let the <i>Z^0</i> decay to quarks, while no decays would be 
allowed if the order were to be reversed. 
 
<p/> 
b) The <code>Pythia</code> <code>readString(string)</code> method actually 
does not do changes itself, but sends on the string either to the 
<code>ParticleData</code> class or to the <code>Settings</code> one, 
depending on whether the string begins with a digit or a letter. 
If desired, it is possible to communicate directly with the corresponding 
<code>ParticleData</code> method: 
<pre> 
    pythia.particleData.readString("111:mayDecay = off"); 
    pythia.particleData.readString("15:2:products = 16 -211"); 
</pre> 
In this case, changes intended for <code>Settings</code> would not be 
understood. 
 
<p/> 
c) Underlying this are commands for all the individual properties in 
the <code>ParticleData</code> class, one for each. These are 
further described below. Thus, an example now reads 
<pre> 
    pythia.particleData.mayDecay(111, false); 
</pre> 
Boolean values should here be given as <code>true</code> or 
<code>false</code>. 
 
<p/> 
d) A simpler and more useful way is to collect all your changes 
in a separate file, with one line per change, e.g. 
<pre> 
    111:mayDecay = off 
</pre> 
The file can be read by the 
<pre> 
    pythia.readFile(fileName); 
</pre> 
method, where <code>fileName</code> is a string, e.g. 
<code>pythia.readFile("main.cmnd")</code> (or an <code>istream</code> 
instead of a <code>fileName</code>). Each line is processed as 
described for the string in 2a). This file can freely mix commands to 
the <code>Settings</code> and <code>ParticleData</code> classes. 
</li> 
 
<li> <p/> 
A routine <code>reInit(fileName)</code> is provided, and can be used to 
zero the particle data table and reinitialize it from scratch. 
Such a call might be useful if several subruns are to be made with 
widely different particle data - normally the maps are only built 
from scratch once, namely when the <code>Pythia()</code> object is 
created. Also, there is no other possibility to restore the default 
values, unlike for the settings. 
</li> 
 
<li> <p/> 
You may at any time obtain a listing of all the particle data by calling 
<pre> 
    pythia.particleData.listAll(); 
</pre> 
The listing is by increasing <code>id</code> number. It shows the basic 
quantities introduced above. Some are abbreviated in the header to fit on 
the lines: <code>spn = spinType</code>, <code>chg = chargeType</code>, 
<code>col = colType</code>, <code>res = isResonance</code>, 
<code>dec = mayDecay && canDecay</code> (the latter checks that decay 
channels have been defined), <code>ext = doExternalDecay</code>, 
<code>vis = isVisible</code> and <code>wid = doForceWidth</code>.<br/> 
 
To list only those particles that were changed (one way or another, the 
listing will not tell what property or decay channel was changed), instead use 
<pre> 
    pythia.particleData.listChanged(); 
</pre> 
(This info is based on a further <code>hasChanged</code> flag of a particle 
or a channel, set <code>true</code> whenever any of the changing methods are 
used. It is possible to manipulate this value, but this is not recommended.) 
By default the internal initialization of the widths of resonances such as 
<i>gamma^*/Z^0, W^+-, t/tbar, H^0</i> do not count as changes; if you want 
to list also those changes instead call <code>listChanged(true)</code>. 
<br/> 
 
To list only one particle, give its <code>id</code> code as argument to 
the <code>list(...)</code> function.. To list a restricted set of particles, 
give in their <code>id</code> codes to <code>list(...)</code> as a 
<code>vector&lt;int></code>. 
</li> 
 
<li> <p/> 
For wholesale changes of particle properties all available data can be 
written out, edited, and then read back in again. These methods are 
mainly intended for expert users. You can choose between two alternative 
syntaxes. 
 
<p/> 
a) XML syntax, using the <code>&lt;particle</code> and 
<code>&lt;channel</code> lines already described. You use the method 
<code>particleData.listXML(fileName)</code> to produce such an XML 
file and <code>particleData.readXML(fileName)</code> to read it back 
in after editing. 
 
<p/> 
b) Fixed/free format, using exactly the same information as illustrated 
for the <code>&lt;particle</code> and <code>&lt;channel</code> lines 
above, but now without any tags. This means that all information fields 
must be provided (if there is no antiparticle then write 
<code>void</code>), in the correct order (while the order is irrelevant 
with XML syntax), and all on one line. Information is written out in 
properly lined-up columns, but the reading is done using free format, 
so fields need only be separated by at least one blank. Each new particle 
is supposed to be separated by (at least) one blank line, whereas no 
blank lines are allowed between the particle line and the subsequent 
decay channel lines, if any.  You use the method 
<code>particleData.listFF(fileName)</code> to produce such a fixed/free 
file and <code>particleData.readFF(fileName)</code> to read it back 
in after editing. 
 
<p/> 
As an alternative to the <code>readXML</code> and <code>readFF</code> 
methods you can also use the 
<code>particleData.reInit(fileName, xmlFormat)</code> method, where 
<code>xmlFormat = true</code> (default) corresponds to reading an XML 
file and <code>xmlFormat = false</code> to a fixed/free format one. 
 
<p/> 
To check that the new particle and decay tables makes sense, you can use 
the <code>particleData.checkTable()</code> method, either directly or by 
switching it on among the standard 
<a href="ErrorChecks.html" target="page">error checks</a>. 
</li> 
 
</ol> 
 
<h2>The public methods</h2> 
 
In the following we present briefly the public methods in the three 
classes used to build up the particle database. The order 
is top-down, i.e from the full table of all particles to a single 
particle to a single channel. 
Note that these methods usually are less elegant and safe than the 
input methods outlined above. If you use any of these methods, it is 
likely to be the ones in the full database, i.e. the first ones to be 
covered in the following. 
 
<p/> 
For convenience, we have grouped related input and output methods 
together. It should be obvious from the context which is which: 
the input is of type <code>void</code> and has an extra last argument, 
namely is the input value, while the output method returns a 
quantity of the expected type. 
 
<h3>The ParticleData methods</h3> 
 
<a name="method1"></a>
<p/><strong>ParticleData::ParticleData() &nbsp;</strong> <br/>
the constructor has no arguments and does not do anything. Internal. 
   
 
<a name="method2"></a>
<p/><strong>void ParticleData::initPtr(Info* infoPtr, Settings* settingsPtrIn, Rndm* rndmPtrIn, CoupSM* coupSMPtrIn) &nbsp;</strong> <br/>
initialize pointers to a few other classes. Internal. 
   
 
<a name="method3"></a>
<p/><strong>bool ParticleData::init(string startFile = &quot;../xmldoc/ParticleData.xml&quot;) &nbsp;</strong> <br/>
read in an XML-style file with particle data and initialize the 
particle data tables accordingly. This command is executed 
in the <code>Pythia</code> constructor, i.e. is mainly for 
internal use. 
<br/><code>argument</code><strong> startFile </strong> (<code>default = <strong>../xmldoc/ParticleData.xml</strong></code>) :  
the name of the data file to be read. When called from the 
<code>Pythia</code> constructor the directory is provided by the 
<code><a href="ProgramFlow.html" target="page">PYTHIA8DATA</a></code> 
environment variable, if set, else by the argument of this constructor, 
which has the default value &quot;../xmldoc&quot;. 
   
   
 
<a name="method4"></a>
<p/><strong>bool ParticleData::reInit(string startFile, bool xmlFormat = true) &nbsp;</strong> <br/>
overwrite the existing database by reading from the specified file. 
Unlike <code>init</code> above this method is not called by the 
<code>Pythia</code> constructor, but is entirely intended for users 
who want to replace the existing particle data with their own. 
<br/><code>argument</code><strong> startFile </strong>  : the path and name of file to be read. 
   
<br/><code>argument</code><strong> xmlFormat </strong>  : if true read the same kind of XML-style file 
as used by <code>init</code>, if not use an alternative "free format" 
file (i.e. without any XML tags, but with well-defined rules 
specifying in which order properties are stored). 
   
   
 
<a name="method5"></a>
<p/><strong>void ParticleData::initWidths( vector&lt;ResonanceWidths*&gt; resonancePtrs) &nbsp;</strong> <br/>
initialize Breit-Wigner shape parameters for all particles, 
and the detailed handling of resonances, i.e. particles with 
perturbatively calculable partial widths, which can be used to 
obtain a mass-dependent Breit-Wigner and a dynamic choice of 
decay channels. Called from <code>Pythia::init()</code>. 
   
 
<a name="method6"></a>
<p/><strong>bool ParticleData::readXML(string inFile, bool reset = true) &nbsp;</strong> <br/>
   
<strong>void ParticleData::listXML(string outFile) &nbsp;</strong> <br/>
read in XML-style data from a file or write it out to a file. For the 
former one can also decide whether to reset all particles to scratch, 
or only overwrite those particles in the file. The former method is 
used by <code>init</code> and <code>reInit</code> above. 
   
 
<a name="method7"></a>
<p/><strong>bool ParticleData::readFF(string inFile, bool reset = true) &nbsp;</strong> <br/>
   
<strong>void ParticleData::listFF(string outFile) &nbsp;</strong> <br/>
read in free-format-style data from a file or write it out to a file. 
For the former one can also decide whether to reset all particles to 
scratch, or only overwrite those particles in the file. The former 
method is used by <code>reInit</code> above. 
   
 
<a name="method8"></a>
<p/><strong>bool ParticleData::readString(string line, bool warn = true, ostream& os = cout) &nbsp;</strong> <br/>
read in a string and interpret is as a new or changed particle data. 
The possibilities are extensively described above. It is normally 
used indirectly, via <code>Pythia::readString(...)</code> and 
<code>Pythia::readFile(...)</code>. 
<br/><code>argument</code><strong> line </strong>  :  
the string to be interpreted as an instruction. 
   
<br/><code>argument</code><strong> warn </strong> (<code>default = <strong>true</strong></code>) :  
write a warning message or not whenever the instruction does not make 
sense, e.g. if the particle does not exist in the database. 
   
<br/><code>argument</code><strong> os </strong> (<code>default = <strong>cout</strong></code>) :  
stream for error printout. 
   
<br/><b>Note:</b> the method returns false if it fails to 
make sense out of the input string. 
   
 
<a name="method9"></a>
<p/><strong>void ParticleData::listAll(ostream& os = cout) &nbsp;</strong> <br/>
   
<strong>void ParticleData::listChanged(ostream& os = cout) &nbsp;</strong> <br/>
   
<strong>void ParticleData::listChangedAndRes(ostream& os = cout) &nbsp;</strong> <br/>
   
<strong>void ParticleData::list(bool changedOnly = false, bool changedRes = true, ostream& os = cout) &nbsp;</strong> <br/>
methods intended to present a listing of particle data in a readable 
format. The first three are special cases of the fourth. The first 
lists all particle data, the second only data for those particles that 
were changed after the original creation of the particle data table. 
Resonances are a special case since they can get their data changed 
by being linked to an object that does the calculation of branching 
ratios. The second method does not count such resonances as changed, 
whereas the third does and thus lists all resonances. 
   
 
<a name="method10"></a>
<p/><strong>void ParticleData::list(int idList, ostream& os = cout) &nbsp;</strong> <br/>
   
<strong>void ParticleData::list(vector&lt;int&gt; idList, ostream& os = cout) &nbsp;</strong> <br/>
list particle data for one single particle, with the identity code as 
input, or for a set of particles, with an input vector of identity codes. 
   
 
<a name="method11"></a>
<p/><strong>void ParticleData::checkTable(ostream& os = cout) &nbsp;</strong> <br/>
   
<strong>void ParticleData::checkTable(int verbosity, ostream& os = cout) &nbsp;</strong> <br/>
check that the particle decay table makes sense, especially for decays. 
<br/><code>argument</code><strong> verbosity </strong>  :  level of checks. 0 is only minimal, 
e.g. if a particle has no open decay channels. 1, which is the level 
of the first method, provides warning if any individual channel is 
closed, except for resonances. 2 also prints the 
branching-ratio-averaged threshold mass. 11 and 12 are like 1 and 2, 
but also include resonances in the detailed checks. 
   
   
 
<a name="method12"></a>
<p/><strong>void ParticleData::addParticle(int id, string name = &quot; &quot;, int spinType = 0, int chargeType = 0, int colType = 0, double m0 = 0., double mWidth = 0., double mMin = 0., double mMax = 0., double tau0 = 0.) &nbsp;</strong> <br/>
   
<strong>void ParticleData::addParticle(int id, string name, string antiName, int spinType = 0, int chargeType = 0, int colType = 0, double m0 = 0., double mWidth = 0., double mMin = 0., double mMax = 0., double tau0 = 0.) &nbsp;</strong> <br/>
add a particle to the decay table; in the first form a particle which is 
its own antiparticle, in the second where a separate antiparticle exists. 
   
 
<a name="method13"></a>
<p/><strong>void ParticleData::setAll(int id, string name, string antiName, int spinType = 0, int chargeType = 0, int colType = 0, double m0 = 0., double mWidth = 0., double mMin = 0., double mMax = 0.,double tau0 = 0.) &nbsp;</strong> <br/>
change all the properties of the particle associated with a given 
identity code. 
   
 
<a name="method14"></a>
<p/><strong>bool ParticleData::isParticle(int id) &nbsp;</strong> <br/>
query whether the particle data table contains the particle of the 
identity code. 
   
 
<a name="method15"></a>
<p/><strong>int ParticleData::nextId(int id) &nbsp;</strong> <br/>
return the identity code of the sequentially next particle stored in table. 
   
 
<a name="method16"></a>
<p/><strong>bool ParticleData::hasAnti(int id) &nbsp;</strong> <br/>
bool whether a distinct antiparticle exists or not. Is true if an 
antiparticle name has been set (and is different from 
<code>void</code>). 
   
 
<a name="method17"></a>
<p/><strong>void ParticleData::name(int id, string name) &nbsp;</strong> <br/>
   
<strong>void ParticleData::antiName(int id, string antiName) &nbsp;</strong> <br/>
   
<strong>void ParticleData::names(int id, string name, string antiName) &nbsp;</strong> <br/>
   
<strong>string ParticleData::name(int id) &nbsp;</strong> <br/>
particle and antiparticle names are stored separately, the sign of 
<code>id</code> determines which of the two is returned, with 
<code>void</code> used to indicate the absence of an antiparticle. 
   
 
<a name="method18"></a>
<p/><strong>void ParticleData::spinType(int id, int spinType) &nbsp;</strong> <br/>
   
<strong>int ParticleData::spinType(int id) &nbsp;</strong> <br/>
the spin type, of the form <i>2 s + 1</i>, with special code 0 
for entries of unknown or indeterminate spin. 
   
 
<a name="method19"></a>
<p/><strong>void ParticleData::chargeType(int id, int chargeType) &nbsp;</strong> <br/>
   
<strong>int ParticleData::chargeType(int id) &nbsp;</strong> <br/>
three times the charge (to make it an integer), taking into account 
the sign of <code>id</code>. 
   
 
<a name="method20"></a>
<p/><strong>double ParticleData::charge(int id) &nbsp;</strong> <br/>
the electrical charge of a particle, equal to 
<code>chargeType(id)/3</code>. 
   
 
<a name="method21"></a>
<p/><strong>void ParticleData::colType(int id, int colType) &nbsp;</strong> <br/>
   
<strong>int ParticleData::colType(int id) &nbsp;</strong> <br/>
the colour type, with 0 uncoloured, 1 triplet, -1 antitriplet and 2 
octet, taking into account the sign of <code>id</code>. 
   
 
<a name="method22"></a>
<p/><strong>void ParticleData::m0(int id, double m0) &nbsp;</strong> <br/>
   
<strong>double ParticleData::m0(int id) &nbsp;</strong> <br/>
the nominal mass <i>m_0</i> (in GeV). 
   
 
<a name="method23"></a>
<p/><strong>void ParticleData::mWidth(int id, double mWidth) &nbsp;</strong> <br/>
   
<strong>double ParticleData::mWidth(int id) &nbsp;</strong> <br/>
the width <i>Gamma</i> of the Breit-Wigner distribution (in GeV). 
   
 
<a name="method24"></a>
<p/><strong>void ParticleData::mMin(int id, double mMin) &nbsp;</strong> <br/>
   
<strong>double ParticleData::mMin(int id) &nbsp;</strong> <br/>
the lower limit of the allowed mass range generated by the Breit-Wigner 
(in GeV). Has no meaning for particles without width, and would 
typically be 0 there. 
   
 
<a name="method25"></a>
<p/><strong>void ParticleData::mMax(int id, double mMax) &nbsp;</strong> <br/>
   
<strong>double ParticleData::mMax(int id) &nbsp;</strong> <br/>
the upper limit of the allowed mass range generated by the Breit-Wigner 
(in GeV). If <i>mMax &lt; mMin</i> then no upper limit is imposed. 
Has no meaning for particles without width, and would typically 
be 0 there. 
   
 
<a name="method26"></a>
<p/><strong>double ParticleData::m0Min(int id) &nbsp;</strong> <br/>
similar to <code>mMin()</code> above, except that for particles with 
no width the <code>m0(id)</code> value is returned. 
   
 
<a name="method27"></a>
<p/><strong>double ParticleData::m0Max(int id) &nbsp;</strong> <br/>
similar to <code>mMax()</code> above, except that for particles with 
no width the <code>m0(id)</code> value is returned. 
   
 
<a name="method28"></a>
<p/><strong>void ParticleData::tau0(int id, double tau0) &nbsp;</strong> <br/>
   
<strong>double ParticleData::tau0(int id) &nbsp;</strong> <br/>
the nominal proper lifetime <i>tau_0</i> (in mm/c). 
   
 
<a name="method29"></a>
<p/><strong>void ParticleData::isResonance(int id, bool isResonance) &nbsp;</strong> <br/>
   
<strong>bool ParticleData::isResonance(int id) &nbsp;</strong> <br/>
a flag telling whether a particle species are considered as a resonance 
or not. Here <a href="ResonanceDecays.html" target="page">"resonance"</a> 
is used as shorthand for any massive particle 
where the decay process should be counted as part of the hard process 
itself, and thus be performed before showers and other event aspects 
are added. Restrictions on allowed decay channels is also directly 
reflected in the cross section of simulated processes, while those of 
normal hadrons and other light particles are not. 
In practice, it is reserved for states above the <i>b bbar</i> 
bound systems in mass, i.e. for <i>W, Z, t</i>, Higgs states, 
supersymmetric states and (most?) other states in any new theory. 
All particles with <code>m0</code> above 20 GeV are by default 
initialized to be considered as resonances. 
   
 
<a name="method30"></a>
<p/><strong>void ParticleData::mayDecay(int id, bool mayDecay) &nbsp;</strong> <br/>
   
<strong>bool ParticleData::mayDecay(int id) &nbsp;</strong> <br/>
a flag telling whether a particle species may decay or not, offering 
the main user switch. Whether a given particle of this kind then actually 
will decay also depends on it having allowed decay channels, and on 
other flags for <a href="ParticleDecays.html" target="page">particle decays</a> 
(or <a href="ResonanceDecays.html" target="page">resonance decays</a>). 
All particles with <code>tau0</code> below 1000 mm are 
by default initialized to allow decays. 
   
 
<a name="method31"></a>
<p/><strong>void ParticleData::doExternalDecays(int id, bool doExternalDecays) &nbsp;</strong> <br/>
   
<strong>bool ParticleData::doExternalDecay(int id) &nbsp;</strong> <br/>
a flag telling whether a particle should be handled by an external 
decay package or not, with the latter default. Can be manipulated as 
described on this page, but should normally not be. Instead the 
<code><a href="ExternalDecays.html" target="page">pythia.decayPtr</a></code> 
method should be provided with the list of relevant particles. 
   
 
<a name="method32"></a>
<p/><strong>void ParticleData::isVisible(int id, bool isVisible) &nbsp;</strong> <br/>
   
<strong>bool ParticleData::isVisible(int id) &nbsp;</strong> <br/>
a flag telling whether a particle species is to be considered as 
visible in a detector or not, as used e.g. in analysis routines. 
By default this includes neutrinos and a few BSM particles 
(gravitino, sneutrinos, neutralinos) that have neither strong nor 
electromagnetic charge, and are not made up of constituents that 
have it. The value of this flag is only relevant if a particle is 
long-lived enough actually to make it to a detector. 
   
 
<a name="method33"></a>
<p/><strong>void ParticleData::doForceWidth(int id, bool doForceWidth) &nbsp;</strong> <br/>
   
<strong>bool ParticleData::doForceWidth(int id) &nbsp;</strong> <br/>
a flag applicable only for resonances (see <code>isResonance</code> above), 
whereby it is possible to force resonances to retain their assigned widths, 
whatever that is, see <a href="ResonanceDecays.html" target="page">Resonance Decays</a> 
for details. The normal behaviour is <code>false</code>, i.e. the width 
is based on hardcoded calculations whenever available. 
   
 
<a name="method34"></a>
<p/><strong>void ParticleData::hasChanged(int id, bool hasChanged) &nbsp;</strong> <br/>
   
<strong>bool ParticleData::hasChanged(int id) &nbsp;</strong> <br/>
keep track of whether the data for a particle has been changed 
in any respect between initialization and the current status. 
Is used e.g. by the <code>listChanged</code> method to determine 
which particles to list. 
   
 
<a name="method35"></a>
<p/><strong>bool ParticleData::useBreitWigner(int id) &nbsp;</strong> <br/>
tells whether a particle will have a Breit-Wigner mass distribution or 
not. Is determined by an internal logic based on the particle width and 
on the value of the 
<code><a href="ParticleData.html" target="page">ParticleData:modeBreitWigner</a></code> 
switch. 
   
 
<a name="method36"></a>
<p/><strong>double ParticleData::constituentMass(int id) &nbsp;</strong> <br/>
is the constituent mass for a quark, hardcoded as 
<i>m_u = m_d = 0.325</i>, <i>m_s = 0.50</i>, <i>m_c = 1.60</i> 
and <i>m_b = 5.0</i> GeV, for a diquark the sum of quark constituent 
masses, and for everything else the same as the ordinary mass. 
   
 
<a name="method37"></a>
<p/><strong>double ParticleData::mSel(int id) &nbsp;</strong> <br/>
returns a mass distributed according to a truncated Breit-Wigner, 
with parameters as described here. Is equal to <code>m0(id)</code> for 
particles without width. 
   
 
<a name="method38"></a>
<p/><strong>double ParticleData::mRun(int id, double mH) &nbsp;</strong> <br/>
calculate the running mass of species <code>id</code> when probed at a 
hard mass scale of <code>mH</code>. Only applied to obtain the 
running quark masses; for all other particle the normal fixed mass 
is used. 
   
 
<a name="method39"></a>
<p/><strong>bool ParticleData::canDecay(int id) &nbsp;</strong> <br/>
true for a particle with at least one decay channel defined. 
   
 
<a name="method40"></a>
<p/><strong>bool ParticleData::isLepton(int id) &nbsp;</strong> <br/>
true for a lepton or an antilepton (including neutrinos). 
   
 
<a name="method41"></a>
<p/><strong>bool ParticleData::isQuark(int id) &nbsp;</strong> <br/>
true for a quark or an antiquark. 
   
 
<a name="method42"></a>
<p/><strong>bool ParticleData::isGluon(int id) &nbsp;</strong> <br/>
true for a gluon. 
   
 
<a name="method43"></a>
<p/><strong>bool ParticleData::isDiquark(int id) &nbsp;</strong> <br/>
true for a diquark or antidiquark. 
   
 
<a name="method44"></a>
<p/><strong>bool ParticleData::isParton() &nbsp;</strong> <br/>
true for a gluon, a quark or antiquark up to the b (but excluding top), 
and a diquark or antidiquark consisting of quarks up to the b. 
   
 
<a name="method45"></a>
<p/><strong>bool ParticleData::isHadron(int id) &nbsp;</strong> <br/>
true for a hadron (made up out of normal quarks and gluons, 
i.e. not for R-hadrons and other exotic states). 
   
 
<a name="method46"></a>
<p/><strong>bool ParticleData::isMeson(int id) &nbsp;</strong> <br/>
true for a meson. 
   
 
<a name="method47"></a>
<p/><strong>bool ParticleData::isBaryon(int id) &nbsp;</strong> <br/>
true for a baryon or antibaryon. 
   
 
<a name="method48"></a>
<p/><strong>bool ParticleData::isOctetHadron(int id) &nbsp;</strong> <br/>
true for an intermediate hadron-like state with a colour octet charge 
as used in the colour octet model for 
<a href="OniaProcesses.html" target="page">onia</a> production. 
   
 
<a name="method49"></a>
<p/><strong>int ParticleData::heaviestQuark(int id) &nbsp;</strong> <br/>
extracts the heaviest quark or antiquark, i.e. one with largest 
<code>id</code> number, for a hadron. 
   
 
<a name="method50"></a>
<p/><strong>int ParticleData::baryonNumberType(int id) &nbsp;</strong> <br/>
is 1 for a quark, 2 for a diquark, 3 for a baryon, the same with a 
minus sign for antiparticles, and else zero. 
   
 
<a name="method51"></a>
<p/><strong>void ParticleData::rescaleBR(int id, double newSumBR = 1.) &nbsp;</strong> <br/>
rescales all partial branching ratios by a common factor, such that 
the sum afterward becomes <code>newSumBR</code>. 
   
 
<a name="method52"></a>
<p/><strong>void setResonancePtr(int id, ResonanceWidths* resonancePtr) &nbsp;</strong> <br/>
set a pointer for a particle kind to a <code>ResonanceWidths</code> object. 
This is done, from inside <code>ParticleData::initWidths</code>, only for 
resonances, i.e. for particles such as <i>Z^0</i>, <i>W^+-</i>, top, 
Higgs, and new unstable states beyond the Standard Model. The presence 
of such an object will allow a more dynamic calculation of partial and 
total widths, as illustrated by the following methods. 
   
 
<a name="method53"></a>
<p/><strong>void ParticleData::resInit(int id) &nbsp;</strong> <br/>
initialize the treatment of a resonance. 
   
 
<a name="method54"></a>
<p/><strong>double ParticleData::resWidth(int id, double mHat, int idInFlav = 0, bool openOnly = false, bool setBR = false) &nbsp;</strong> <br/>
calculate the total with for a resonance of a given current mass, 
optionally including coupling to incoming flavour state (consider 
the <i>gamma*/Z^0</i> combination), optionally excluding decay 
channels that have been closed by the user, and optionally storing 
the results in the normal decay table. 
   
 
<a name="method55"></a>
<p/><strong>double ParticleData::resWidthOpen(int id, double mHat, int idInFlav = 0) &nbsp;</strong> <br/>
special case of <code>resWidth</code>, where only open channels are 
included, but results are not stored in the normal decay table. 
   
 
<a name="method56"></a>
<p/><strong>double ParticleData::resWidthStore(int id, double mHat, int idInFlav = 0) &nbsp;</strong> <br/>
special case of <code>resWidth</code>, where only open channels are 
included, and results are stored in the normal decay table. 
   
 
<a name="method57"></a>
<p/><strong>double ParticleData::resOpenFrac(int id1, int id2 = 0, int id3 = 0) &nbsp;</strong> <br/>
calculate the fraction of the full branching ratio that is left 
open by the user choice of allowed decay channels. Can be applied 
to a final state with up to three resonances. Since the procedure 
is multiplicative, it would be easy to generalize also to more. 
   
 
<a name="method58"></a>
<p/><strong>double ParticleData::resWidthRescaleFactor(int id) &nbsp;</strong> <br/>
the factor used to rescale all partial widths in case the total 
width is being forced to a specific value by the user. 
   
 
<a name="method59"></a>
<p/><strong>double ParticleData::resWidthChan(int id, double mHat, int idAbs1 = 0, int idAbs2 = 0) &nbsp;</strong> <br/>
special case to calculate one final-state width; currently only used 
for Higgs decay to <i>q qbar</i>, <i>g g</i> or 
<i>gamma gamma</i>. 
   
 
<a name="method60"></a>
<p/><strong>ParticleDataEntry* ParticleData::particleDataEntryPtr(int id) &nbsp;</strong> <br/>
returns a pointer to the <code>ParticleDataEntry</code> object. 
The methods in the next section can then be used to manipulate 
this object. 
   
  
<h3>The ParticleDataEntry methods</h3> 
 
Most of the methods that can be applied to a single 
<code>ParticleDataEntry</code> object are almost identical with 
those used above for the <code>ParticleData</code>, except 
that the <code>id</code> argument is no longer needed to find 
the right entry in the table. By and large, this makes direct 
access to the <code>ParticleDataEntry</code> methods superfluous. 
There are a few methods that are unique to each class, however. 
Furthermore, to avoid some naming ambiguities, many methods that 
set values begin with <code>set</code>. 
 
<a name="method61"></a>
<p/><strong>ParticleDataEntry::ParticleDataEntry(int id = 0, string name = &quot; &quot;, int spinType = 0, int chargeType = 0, int colType = 0, double m0 = 0., double mWidth = 0., double mMin = 0., double mMax = 0., double tau0 = 0.) &nbsp;</strong> <br/>
   
<strong>ParticleDataEntry::ParticleDataEntry(int id, string name, string antiName, int spinType = 0, int chargeType = 0, int colType = 0, double m0 = 0., double mWidth = 0., double mMin = 0., double mMax = 0., double tau0 = 0.) &nbsp;</strong> <br/>
there are two alternative constructors, that both expect the 
properties of a particle as input. The first assumes that there 
is only one particle, the latter that there is a 
particle-antiparticle pair (but if the antiparticle name is 
<code>void</code> one reverts back to the particle-only case). 
   
 
<a name="method62"></a>
<p/><strong>ParticleDataEntry::~ParticleDataEntry &nbsp;</strong> <br/>
the destructor is needed to delete any <code>ResonanceWidths</code> 
objects that have been created and linked to the respective particle. 
   
 
<a name="method63"></a>
<p/><strong>void ParticleDataEntry::setDefaults() &nbsp;</strong> <br/>
initialize some particle flags with default values, e.g. whether 
a particle is a resonance, may decay, or is visible. Is called from the 
constructors and from <code>setAll</code>. 
   
 
<a name="method64"></a>
<p/><strong>void ParticleDataEntry::initPtr(ParticleData* particleDataPtrIn) &nbsp;</strong> <br/>
initialize pointer back to the whole database (so that masses of 
decay products can be accessed, e.g.). 
   
 
<a name="method65"></a>
<p/><strong>void ParticleDataEntry::setAll( string name, string antiName, int spinType = 0, int chargeType = 0, int colType = 0, double m0 = 0., double mWidth = 0., double mMin = 0., double mMax = 0.,double tau0 = 0.) &nbsp;</strong> <br/>
change all the properties of the particle associated with a given 
identity code. 
   
 
<a name="method66"></a>
<p/><strong>int ParticleDataEntry::id() &nbsp;</strong> <br/>
the PDG identity code. 
   
 
<a name="method67"></a>
<p/><strong>bool ParticleDataEntry::hasAnti() &nbsp;</strong> <br/>
tell whether a separate antiparticle exists. 
   
 
<a name="method68"></a>
<p/><strong>void ParticleDataEntry::setName(string name) &nbsp;</strong> <br/>
   
<strong>void ParticleDataEntry::setAntiName(string antiName) &nbsp;</strong> <br/>
   
<strong>void ParticleDataEntry::setNames(string name, string antiName) &nbsp;</strong> <br/>
   
<strong>string ParticleDataEntry::name(int id = 1) &nbsp;</strong> <br/>
set or get the particle or antiparticle name. Only the sign of 
<code>id</code> is needed to distinguish particle/antiparticle. 
   
 
<a name="method69"></a>
<p/><strong>void ParticleDataEntry::setSpinType(int spinType) &nbsp;</strong> <br/>
   
<strong>int ParticleDataEntry::spinType() &nbsp;</strong> <br/>
set or get the particle spin type, i.e. <i>2 s + 1</i>, or 0 in some 
special cases. 
   
 
<a name="method70"></a>
<p/><strong>void ParticleDataEntry::setChargeType(int chargeType) &nbsp;</strong> <br/>
   
<strong>int ParticleDataEntry::chargeType(int id = 1) &nbsp;</strong> <br/>
   
<strong>double ParticleDataEntry::charge(int id = 1) &nbsp;</strong> <br/>
set or get the particle charge type, i.e. three times the charge, 
or the charge itself. Only the sign of <code>id</code> is needed 
to distinguish particle/antiparticle. 
   
 
<a name="method71"></a>
<p/><strong>void ParticleDataEntry::setColType(int colType) &nbsp;</strong> <br/>
   
<strong>int ParticleDataEntry::colType(int id = 1) &nbsp;</strong> <br/>
set or get the particle colour type, 0 for singlet, 1 for triplet, 
-1 for antitriplet, 2 for octet. Only the sign of <code>id</code> 
is needed to distinguish particle/antiparticle. 
   
 
<a name="method72"></a>
<p/><strong>void ParticleDataEntry::setM0(double m0) &nbsp;</strong> <br/>
   
<strong>double ParticleDataEntry::m0() &nbsp;</strong> <br/>
the nominal mass <i>m_0</i> (in GeV). 
   
 
<a name="method73"></a>
<p/><strong>void ParticleDataEntry::setMWidth(double mWidth) &nbsp;</strong> <br/>
   
<strong>double ParticleDataEntry::mWidth() &nbsp;</strong> <br/>
the width <i>Gamma</i> of the Breit-Wigner distribution (in GeV). 
   
 
<a name="method74"></a>
<p/><strong>void ParticleDataEntry::setMMin(double mMin) &nbsp;</strong> <br/>
   
<strong>double ParticleDataEntry::mMin() &nbsp;</strong> <br/>
the lower limit of the allowed mass range generated by the Breit-Wigner 
(in GeV). Has no meaning for particles without width, and would 
typically be 0 there. 
   
 
<a name="method75"></a>
<p/><strong>void ParticleDataEntry::setMMax(double mMax) &nbsp;</strong> <br/>
   
<strong>double ParticleDataEntry::mMax() &nbsp;</strong> <br/>
the upper limit of the allowed mass range generated by the Breit-Wigner 
(in GeV). If <i>mMax &lt; mMin</i> then no upper limit is imposed. 
Has no meaning for particles without width, and would typically 
be 0 there. 
   
 
<a name="method76"></a>
<p/><strong>double ParticleDataEntry::m0Min() &nbsp;</strong> <br/>
similar to <code>mMin()</code> above, except that for particles with 
no width the <code>m0(id)</code> value is returned. 
   
 
<a name="method77"></a>
<p/><strong>double ParticleDataEntry::m0Max() &nbsp;</strong> <br/>
similar to <code>mMax()</code> above, except that for particles with 
no width the <code>m0(id)</code> value is returned. 
   
 
<a name="method78"></a>
<p/><strong>void ParticleDataEntry::setTau0(double tau0) &nbsp;</strong> <br/>
   
<strong>double ParticleDataEntry::tau0() &nbsp;</strong> <br/>
the nominal proper lifetime <i>tau_0</i> (in mm/c). 
   
 
<a name="method79"></a>
<p/><strong>void ParticleDataEntry::setIsResonance(bool isResonance) &nbsp;</strong> <br/>
   
<strong>bool ParticleDataEntry::isResonance() &nbsp;</strong> <br/>
a flag telling whether a particle species are considered as a resonance 
or not. Here <a href="ResonanceDecays.html" target="page">"resonance"</a> 
is used as shorthand for any massive particle 
where the decay process should be counted as part of the hard process 
itself, and thus be performed before showers and other event aspects 
are added. Restrictions on allowed decay channels is also directly 
reflected in the cross section of simulated processes, while those of 
normal hadrons and other light particles are not. 
In practice, it is reserved for states above the <i>b bbar</i> 
bound systems in mass, i.e. for <i>W, Z, t</i>, Higgs states, 
supersymmetric states and (most?) other states in any new theory. 
All particles with <code>m0</code> above 20 GeV are by default 
initialized to be considered as resonances. 
   
 
<a name="method80"></a>
<p/><strong>void ParticleDataEntry::setMayDecay(bool mayDecay) &nbsp;</strong> <br/>
   
<strong>bool ParticleDataEntry::mayDecay() &nbsp;</strong> <br/>
a flag telling whether a particle species may decay or not, offering 
the main user switch. Whether a given particle of this kind then actually 
will decay also depends on it having allowed decay channels, and on 
other flags for <a href="ParticleDecays.html" target="page">particle decays</a> 
(or <a href="ResonanceDecays.html" target="page">resonance decays</a>). 
All particles with <code>tau0</code> below 1000 mm are 
by default initialized to allow decays. 
   
 
<a name="method81"></a>
<p/><strong>void ParticleDataEntry::setDoExternalDecays(bool doExternalDecays) &nbsp;</strong> <br/>
   
<strong>bool ParticleDataEntry::doExternalDecay() &nbsp;</strong> <br/>
a flag telling whether a particle should be handled by an external 
decay package or not, with the latter default. Can be manipulated as 
described on this page, but should normally not be. Instead the 
<code><a href="ExternalDecays.html" target="page">pythia.decayPtr</a></code> 
method should be provided with the list of relevant particles. 
   
 
<a name="method82"></a>
<p/><strong>void ParticleDataEntry::setIsVisible(bool isVisible) &nbsp;</strong> <br/>
   
<strong>bool ParticleDataEntry::isVisible() &nbsp;</strong> <br/>
a flag telling whether a particle species is to be considered as 
visible in a detector or not, as used e.g. in analysis routines. 
By default this includes neutrinos and a few BSM particles 
(gravitino, sneutrinos, neutralinos) that have neither strong nor 
electromagnetic charge, and are not made up of constituents that 
have it. The value of this flag is only relevant if a particle is 
long-lived enough actually to make it to a detector. 
   
 
<a name="method83"></a>
<p/><strong>void ParticleDataEntry::setDoForceWidth(bool doForceWidth) &nbsp;</strong> <br/>
   
<strong>bool ParticleDataEntry::doForceWidth() &nbsp;</strong> <br/>
a flag applicable only for resonances (see <code>isResonance</code> above), 
whereby it is possible to force resonances to retain their assigned widths, 
whatever that is, see <a href="ResonanceDecays.html" target="page">Resonance Decays</a> 
for details. The normal behaviour is <code>false</code>, i.e. the width 
is based on hardcoded calculations whenever available. 
   
 
<a name="method84"></a>
<p/><strong>void ParticleDataEntry::setHasChanged(bool hasChanged) &nbsp;</strong> <br/>
   
<a name="method85"></a>
<p/><strong>void ParticleDataEntry::hasChanged(bool hasChanged) &nbsp;</strong> <br/>
keep track of whether the data for a particle has been changed 
in any respect between initialization and the current status. 
Is used e.g. by the <code>ParticleData::listChanged</code> method 
to determine which particles to list. 
   
 
<a name="method86"></a>
<p/><strong>void ParticleDataEntry::initBWmass() &nbsp;</strong> <br/>
Prepare the Breit-Wigner mass selection by precalculating 
frequently-used expressions. 
   
 
<a name="method87"></a>
<p/><strong>double ParticleDataEntry::constituentMass() &nbsp;</strong> <br/>
is the constituent mass for a quark, hardcoded as 
<i>m_u = m_d = 0.325</i>, <i>m_s = 0.50</i>, <i>m_c = 1.60</i> 
and <i>m_b = 5.0</i> GeV, for a diquark the sum of quark constituent 
masses, and for everything else the same as the ordinary mass. 
   
 
<a name="method88"></a>
<p/><strong>double ParticleDataEntry::mSel() &nbsp;</strong> <br/>
give the mass of a particle, either at the nominal value 
or picked according to a (linear or quadratic) Breit-Wigner. 
   
 
<a name="method89"></a>
<p/><strong>double ParticleDataEntry::mRun(double mH) &nbsp;</strong> <br/>
calculate the running quark mass at a hard scale <code>mH</code>. 
For other particles the on-shell mass is given. 
   
 
<a name="method90"></a>
<p/><strong>bool ParticleDataEntry::useBreitWigner() &nbsp;</strong> <br/>
tells whether a particle will have a Breit-Wigner mass distribution or 
not. Is determined by an internal logic based on the particle width and 
on the value of the <code><a href="ParticleData.html" target="page"> 
ParticleData:modeBreitWigner</a></code> switch. 
   
 
<a name="method91"></a>
<p/><strong>bool ParticleDataEntry::canDecay(int id) &nbsp;</strong> <br/>
true for a particle with at least one decay channel defined. 
   
 
<a name="method92"></a>
<p/><strong>bool ParticleDataEntry::isLepton() &nbsp;</strong> <br/>
true for a lepton or an antilepton (including neutrinos). 
   
 
<a name="method93"></a>
<p/><strong>bool ParticleDataEntry::isQuark() &nbsp;</strong> <br/>
true for a quark or an antiquark. 
   
 
<a name="method94"></a>
<p/><strong>bool ParticleDataEntry::isGluon() &nbsp;</strong> <br/>
true for a gluon. 
   
 
<a name="method95"></a>
<p/><strong>bool ParticleDataEntry::isDiquark() &nbsp;</strong> <br/>
true for a diquark or antidiquark. 
   
 
<a name="method96"></a>
<p/><strong>bool ParticleDataEntry::isParton() &nbsp;</strong> <br/>
true for a gluon, a quark or antiquark up to the b (but excluding top), 
and a diquark or antidiquark consisting of quarks up to the b. 
   
 
<a name="method97"></a>
<p/><strong>bool ParticleDataEntry::isHadron() &nbsp;</strong> <br/>
true for a hadron (made up out of normal quarks and gluons, 
i.e. not for R-hadrons and other exotic states). 
   
 
<a name="method98"></a>
<p/><strong>bool ParticleDataEntry::isMeson() &nbsp;</strong> <br/>
true for a meson. 
   
 
<a name="method99"></a>
<p/><strong>bool ParticleDataEntry::isBaryon() &nbsp;</strong> <br/>
true for a baryon or antibaryon. 
   
 
<a name="method100"></a>
<p/><strong>bool ParticleDataEntry::isOctetHadron() &nbsp;</strong> <br/>
true for an intermediate hadron-like state with a colour octet charge 
as used in the colour octet model for 
<a href="OniaProcesses.html" target="page">onia</a> production. 
   
 
<a name="method101"></a>
<p/><strong>int ParticleDataEntry::heaviestQuark(int id) &nbsp;</strong> <br/>
extracts the heaviest quark or antiquark, i.e. one with largest 
<code>id</code> number, for a hadron. Only the sign of the input 
argument is relevant. 
   
 
<a name="method102"></a>
<p/><strong>int ParticleDataEntry::baryonNumberType(int id) &nbsp;</strong> <br/>
is 1 for a quark, 2 for a diquark, 3 for a baryon, the same with a 
minus sign for antiparticles, and else zero. Only the sign of the 
input argument is relevant. 
   
 
<a name="method103"></a>
<p/><strong>void ParticleDataEntry::clearChannels() &nbsp;</strong> <br/>
resets to an empty decay table. 
   
 
<a name="method104"></a>
<p/><strong>void ParticleDataEntry::addChannel(int onMode = 0, double bRatio = 0., int meMode = 0, int prod0 = 0, int prod1 = 0, int prod2 = 0, int prod3 = 0, int prod4 = 0, int prod5 = 0, int prod6 = 0,  int prod7 = 0,) &nbsp;</strong> <br/>
adds a decay channel with up to 8 products. 
   
 
<a name="method105"></a>
<p/><strong>int ParticleDataEntry::sizeChannels() &nbsp;</strong> <br/>
returns the number of decay channels for a particle. 
   
 
<a name="method106"></a>
<p/><strong>DecayChannel& ParticleDataEntry::channel(int i) &nbsp;</strong> <br/>
   
<strong>const DecayChannel& ParticleDataEntry::channel(int i) &nbsp;</strong> <br/>
gain access to a specified channel in the decay table. 
   
 
<a name="method107"></a>
<p/><strong>void ParticleDataEntry::rescaleBR(double newSumBR = 1.) &nbsp;</strong> <br/>
rescales all partial branching ratios by a common factor, such that 
the sum afterward becomes <code>newSumBR</code>. 
   
 
<a name="method108"></a>
<p/><strong>bool ParticleDataEntry::preparePick(int idSgn, double mHat = 0., int idInFlav = 0) &nbsp;</strong> <br/>
prepare to pick a decay channel. 
   
 
<a name="method109"></a>
<p/><strong>DecayChannel& ParticleDataEntry::pickChannel() &nbsp;</strong> <br/>
pick a decay channel according to branching ratios from 
<code>preparePick</code>. 
   
 
<a name="method110"></a>
<p/><strong>void ParticleDataEntry::setResonancePtr(ResonanceWidths* resonancePtr) &nbsp;</strong> <br/>
   
<strong>ResonanceWidths* ParticleDataEntry::getResonancePtr() &nbsp;</strong> <br/>
set or get a pointer to an object that can be used for dynamic calculation 
of partial and total resonance widths. Here a resonance is a particle 
such as top, <i>Z^0</i>, <i>W^+-</i>, Higgs, and new unstable states 
beyond the Standard Model. 
   
 
<a name="method111"></a>
<p/><strong>void ParticleDataEntry::resInit(Info* infoPtrIn, Settings* settingsPtrIn, ParticleData* particleDataPtrIn, CoupSM* coupSMPtrIn) &nbsp;</strong> <br/>
initialize the treatment of a resonance. 
   
 
<a name="method112"></a>
<p/><strong>double ParticleDataEntry::resWidth(int idSgn, double mHat, int idInFlav = 0, bool openOnly = false, bool setBR = false) &nbsp;</strong> <br/>
calculate the total with for a resonance of a given current mass, 
optionally including coupling to incoming flavour state (consider 
the <i>gamma*/Z^0</i> combination), optionally excluding decay 
channels that have been closed by the user, and optionally storing 
the results in the normal decay table. For the first argument only 
the sign is relevant. 
   
 
<a name="method113"></a>
<p/><strong>double ParticleDataEntry::resWidthOpen(int idSgn, double mHat, int idInFlav = 0) &nbsp;</strong> <br/>
special case of <code>resWidth</code>, where only open channels are 
included, but results are not stored in the normal decay table. 
   
 
<a name="method114"></a>
<p/><strong>double ParticleDataEntry::resWidthStore(int idSgn, double mHat, int idInFlav = 0) &nbsp;</strong> <br/>
special case of <code>resWidth</code>, where only open channels are 
included, and results are stored in the normal decay table. 
   
 
<a name="method115"></a>
<p/><strong>double ParticleDataEntry::resOpenFrac(int idSgn) &nbsp;</strong> <br/>
calculate the fraction of the full branching ratio that is left 
open by the user choice of allowed decay channels. 
   
 
<a name="method116"></a>
<p/><strong>double ParticleDataEntry::resWidthRescaleFactor() &nbsp;</strong> <br/>
the factor used to rescale all partial widths in case the total 
width is being forced to a specific value by the user. 
   
 
<a name="method117"></a>
<p/><strong>double ParticleDataEntry::resWidthChan(double mHat, int idAbs1 = 0, int idAbs2 = 0) &nbsp;</strong> <br/>
special case to calculate one final-state width; currently only used 
for Higgs decay to <i>q qbar</i>, <i>g g</i> or 
<i>gamma gamma</i>. 
   
 
<h3>The DecayChannel methods</h3> 
 
The properties stored in an individual decay channel can be set or get 
by the methods in this section. 
 
<a name="method118"></a>
<p/><strong>DecayChannel::DecayChannel(int onMode = 0, double bRatio = 0., int meMode = 0, int prod0 = 0, int prod1 = 0, int prod2 = 0, int prod3 = 0, int prod4 = 0, int prod5 = 0, int prod6 = 0, int prod7 = 0) &nbsp;</strong> <br/>
the constructor for a decay channel. Internal. 
   
 
<a name="method119"></a>
<p/><strong>void DecayChannel::onMode(int onMode) &nbsp;</strong> <br/>
   
<strong>int DecayChannel::onMode() &nbsp;</strong> <br/>
set or get the <code>onMode</code> of a decay channel,<br/> 
0 if a channel is off,<br/> 
1 if on,<br/> 
2 if on for a particle but off for an antiparticle,<br/> 
3 if on for an antiparticle but off for a particle.<br/> 
If a particle is its own antiparticle then 2 is on and 3 off 
but, of course, for such particles it is much simpler and safer 
to use only 1 and 0.<br/> 
The 2 and 3 options can be used e.g. to encode CP violation in 
B decays, or to let the <i>W</i>'s in a <i>q qbar &rarr; W^+ W^-</i> 
process decay in different channels. 
   
 
<a name="method120"></a>
<p/><strong>void DecayChannel::bRatio(double bRatio, bool countAsChanged = true) &nbsp;</strong> <br/>
   
<strong>double DecayChannel::bRatio() &nbsp;</strong> <br/>
set or get the branching ratio of the channel. Second argument only 
for internal use. 
   
 
<a name="method121"></a>
<p/><strong>void DecayChannel::rescaleBR(double fac) &nbsp;</strong> <br/>
multiply the current branching ratio by <code>fac</code>. 
   
 
<a name="method122"></a>
<p/><strong>void DecayChannel::meMode(int meMode) &nbsp;</strong> <br/>
   
<strong>int DecayChannel::meMode() &nbsp;</strong> <br/>
set or get the mode of processing this channel, possibly with matrix 
elements (see the <a href="ParticleDecays.html" target="page">particle decays</a> 
and <a href="ResonanceDecays.html" target="page">resonance decays</a> descriptions). 
   
 
<a name="method123"></a>
<p/><strong>void DecayChannel::multiplicity(int multiplicity) &nbsp;</strong> <br/>
   
<strong>int DecayChannel::multiplicity() &nbsp;</strong> <br/>
set or get the number of decay products in a channel, at most 8. 
(Is normally not to be set by hand, since it is automatically 
updated whenever the products list is changed.) 
   
 
<a name="method124"></a>
<p/><strong>void DecayChannel::product(int i, int product) &nbsp;</strong> <br/>
   
<strong>int DecayChannel::product(int i) &nbsp;</strong> <br/>
set or get a list of the decay products, 8 products 0 &lt;= i &lt; 8, 
with trailing unused ones set to 0. 
   
 
<a name="method125"></a>
<p/><strong>void DecayChannel::setHasChanged(bool hasChanged) &nbsp;</strong> <br/>
   
<strong>bool DecayChannel::hasChanged() &nbsp;</strong> <br/>
used for internal purposes, to know which decay modes have been changed. 
   
 
<a name="method126"></a>
<p/><strong>bool DecayChannel::contains(int id1) &nbsp;</strong> <br/>
   
<strong>bool DecayChannel::contains(int id1, int id2) &nbsp;</strong> <br/>
   
<strong>bool DecayChannel::contains(int id1, int id2, int id3) &nbsp;</strong> <br/>
find if the decay product list contains the one, two or three particle 
identities provided. If the same code is repeated then so must it be in 
the products list. Matching also requires correct sign. 
   
 
<a name="method127"></a>
<p/><strong>void DecayChannel::currentBR(double currentBR) &nbsp;</strong> <br/>
   
<strong>double DecayChannel::currentBR() &nbsp;</strong> <br/>
set or get the current branching ratio, taking into account on/off 
switches and dynamic width for resonances. For internal use. 
   
 
<a name="method128"></a>
<p/><strong>void DecayChannel::onShellWidth(double onShellWidth) &nbsp;</strong> <br/>
   
<strong>double DecayChannel::onShellWidth() &nbsp;</strong> <br/>
set or get the current partial width of the channel; intended for 
resonances where the widths are recalculated based on the current 
resonance mass. For internal use. 
   
 
<a name="method129"></a>
<p/><strong>void DecayChannel::onShellWidthFactor(double factor) &nbsp;</strong> <br/>
multiply the current partial width by <code>factor</code>. 
   
 
<a name="method130"></a>
<p/><strong>void DecayChannel::openSec(int idSgn, double openSecIn) &nbsp;</strong> <br/>
   
<strong>double DecayChannel::openSec(nt idSgn) &nbsp;</strong> <br/>
set or get the fraction of secondary open widths, separately for 
positive and negative particles. For internal use. 
   
 
</body>
</html>
 
<!-- Copyright (C) 2014 Torbjorn Sjostrand -->