Measurement of the energy density as a function of pseudorapidity in proton-proton collisions at $\sqrt{s} =$ 13 TeV

A measurement of the energy density in proton–proton collisions at a centre-of-mass energy of $\sqrt{s} =13$ $\,\text {TeV}$ is presented. The data have been recorded with the CMS experiment at the LHC during low luminosity operations in 2015. The energy density is studied as a function of pseudorapidity in the ranges $-,6.6