/usr/include/OGRE/Plugins/ParticleFX/ is in libogre-dev 1.7.4-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/OGRE/Plugins/ParticleFX/OgreAreaEmitter.h
/usr/include/OGRE/Plugins/ParticleFX/OgreBoxEmitter.h
/usr/include/OGRE/Plugins/ParticleFX/OgreBoxEmitterFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreColourFaderAffector.h
/usr/include/OGRE/Plugins/ParticleFX/OgreColourFaderAffector2.h
/usr/include/OGRE/Plugins/ParticleFX/OgreColourFaderAffectorFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreColourFaderAffectorFactory2.h
/usr/include/OGRE/Plugins/ParticleFX/OgreColourImageAffector.h
/usr/include/OGRE/Plugins/ParticleFX/OgreColourImageAffectorFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreColourInterpolatorAffector.h
/usr/include/OGRE/Plugins/ParticleFX/OgreColourInterpolatorAffectorFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreCylinderEmitter.h
/usr/include/OGRE/Plugins/ParticleFX/OgreCylinderEmitterFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreDeflectorPlaneAffector.h
/usr/include/OGRE/Plugins/ParticleFX/OgreDeflectorPlaneAffectorFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreDirectionRandomiserAffector.h
/usr/include/OGRE/Plugins/ParticleFX/OgreDirectionRandomiserAffectorFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreEllipsoidEmitter.h
/usr/include/OGRE/Plugins/ParticleFX/OgreEllipsoidEmitterFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreHollowEllipsoidEmitter.h
/usr/include/OGRE/Plugins/ParticleFX/OgreHollowEllipsoidEmitterFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreLinearForceAffector.h
/usr/include/OGRE/Plugins/ParticleFX/OgreLinearForceAffectorFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreParticleFXPlugin.h
/usr/include/OGRE/Plugins/ParticleFX/OgreParticleFXPrerequisites.h
/usr/include/OGRE/Plugins/ParticleFX/OgrePointEmitter.h
/usr/include/OGRE/Plugins/ParticleFX/OgrePointEmitterFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreRingEmitter.h
/usr/include/OGRE/Plugins/ParticleFX/OgreRingEmitterFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreRotationAffector.h
/usr/include/OGRE/Plugins/ParticleFX/OgreRotationAffectorFactory.h
/usr/include/OGRE/Plugins/ParticleFX/OgreScaleAffector.h
/usr/include/OGRE/Plugins/ParticleFX/OgreScaleAffectorFactory.h