These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 0.98 s (backtrack: 0/20).

[ebuild  N     ] sci-physics/clhep-2.4.7.2:2/2.4.7.2::gentoo  USE="threads -doc -static-libs -test" 932 KiB

Total: 1 package (1 new), Size of downloads: 932 KiB