/usr/include/ThePEG/PDT/ is in libthepeg-dev 1.8.0-3build1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ThePEG/PDT/BreitWignerMass.h
/usr/include/ThePEG/PDT/ColourPairDecayer.h
/usr/include/ThePEG/PDT/CombinedMatcher.h
/usr/include/ThePEG/PDT/ConstituentParticleData.h
/usr/include/ThePEG/PDT/DalitzDecayer.h
/usr/include/ThePEG/PDT/DecayMode.fh
/usr/include/ThePEG/PDT/DecayMode.h
/usr/include/ThePEG/PDT/DecayMode.xh
/usr/include/ThePEG/PDT/Decayer.fh
/usr/include/ThePEG/PDT/Decayer.h
/usr/include/ThePEG/PDT/DummyDecayer.h
/usr/include/ThePEG/PDT/EnumParticles.h
/usr/include/ThePEG/PDT/FlatDecayer.h
/usr/include/ThePEG/PDT/MassGenerator.fh
/usr/include/ThePEG/PDT/MassGenerator.h
/usr/include/ThePEG/PDT/Matcher.h
/usr/include/ThePEG/PDT/Matcher.tcc
/usr/include/ThePEG/PDT/MatcherBase.h
/usr/include/ThePEG/PDT/MixedParticleData.fh
/usr/include/ThePEG/PDT/MixedParticleData.h
/usr/include/ThePEG/PDT/OmegaPhi3PiDecayer.h
/usr/include/ThePEG/PDT/Onium3GDecayer.h
/usr/include/ThePEG/PDT/PDT.h
/usr/include/ThePEG/PDT/PID.h
/usr/include/ThePEG/PDT/ParticleData.h
/usr/include/ThePEG/PDT/ParticleData.xh
/usr/include/ThePEG/PDT/QuarksToHadronsDecayer.h
/usr/include/ThePEG/PDT/RemnantData.fh
/usr/include/ThePEG/PDT/RemnantData.h
/usr/include/ThePEG/PDT/RemnantDecayer.fh
/usr/include/ThePEG/PDT/RemnantDecayer.h
/usr/include/ThePEG/PDT/SimpleBaryonRemnantDecayer.h
/usr/include/ThePEG/PDT/StandardMatchers.h
/usr/include/ThePEG/PDT/Tau2HadronsDecayer.h
/usr/include/ThePEG/PDT/V2PPDecayer.h
/usr/include/ThePEG/PDT/WeakToHadronsDecayer.h
/usr/include/ThePEG/PDT/WidthGenerator.fh
/usr/include/ThePEG/PDT/WidthGenerator.h