/usr/lib/x86_64-linux-gnu/libCLHEP.so.2.1 is in libclhep2.1v5 2.1.4.1+dfsg-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libCLHEP.so.2.1.4.1
/usr/lib/x86_64-linux-gnu/libCLHEP.so.2.1.4.1