/usr/include/CLHEP/Vector/ is in libclhep-dev 2.1.4.1+dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/CLHEP/Vector/AxisAngle.h
/usr/include/CLHEP/Vector/AxisAngle.icc
/usr/include/CLHEP/Vector/Boost.h
/usr/include/CLHEP/Vector/Boost.icc
/usr/include/CLHEP/Vector/BoostX.h
/usr/include/CLHEP/Vector/BoostX.icc
/usr/include/CLHEP/Vector/BoostY.h
/usr/include/CLHEP/Vector/BoostY.icc
/usr/include/CLHEP/Vector/BoostZ.h
/usr/include/CLHEP/Vector/BoostZ.icc
/usr/include/CLHEP/Vector/EulerAngles.h
/usr/include/CLHEP/Vector/EulerAngles.icc
/usr/include/CLHEP/Vector/LorentzRotation.h
/usr/include/CLHEP/Vector/LorentzRotation.icc
/usr/include/CLHEP/Vector/LorentzVector.h
/usr/include/CLHEP/Vector/LorentzVector.icc
/usr/include/CLHEP/Vector/Rotation.h
/usr/include/CLHEP/Vector/Rotation.icc
/usr/include/CLHEP/Vector/RotationInterfaces.h
/usr/include/CLHEP/Vector/RotationInterfaces.icc
/usr/include/CLHEP/Vector/RotationX.h
/usr/include/CLHEP/Vector/RotationX.icc
/usr/include/CLHEP/Vector/RotationY.h
/usr/include/CLHEP/Vector/RotationY.icc
/usr/include/CLHEP/Vector/RotationZ.h
/usr/include/CLHEP/Vector/RotationZ.icc
/usr/include/CLHEP/Vector/Sqr.h
/usr/include/CLHEP/Vector/ThreeVector.h
/usr/include/CLHEP/Vector/ThreeVector.icc
/usr/include/CLHEP/Vector/TwoVector.h
/usr/include/CLHEP/Vector/TwoVector.icc
/usr/include/CLHEP/Vector/ZMxpv.h
/usr/include/CLHEP/Vector/defs.h