Pseudorapidity distributions of charged hadrons in XeXe collisions at $\sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = 5.44\,\mathrm{TeV}$

Measurements of the pseudorapidity distributions of charged hadrons produced in xenon-xenon collisions at $\sqrt{\smash[b]{s_{_{\mathrm{NN}}}}} = 5.44\,\mathrm{TeV}$ are presented. The measurements are based on data collected by the CMS experiment at the CERN LHC. The yield of primary charged hadrons produced in non-single-diffractive xenon-xenon collisions in the pseudorapidity range $\left|\eta\right|<3.2$ is determined using the silicon pixel detector in the CMS tracking system. For events with the largest overlap between the colliding nuclei, the charged-hadron pseudorapidity density at midrapidity is found to be $1187 \pm 36$ (syst.). The rapidity distribution of charged hadrons is also presented and is found to be independent of rapidity around midrapidity, a feature that is not predicted by Monte Carlo event generators. Comparisons of per-participant charged-particle multiplicities between xenon-xenon and lead-lead collisions at similar energies show that particle production is driven by the collision geometry instead of the system size.