Inclusive heavy-flavour production at central and forward rapidity in Xe–Xe collisions at s NN = 5.44 TeV

The first measurements of the production of muons and electrons from heavy-flavour hadron decays in Xe–Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV, using the ALICE detector at the LHC, are reported. The measurement of the nuclear modification factor $R_{\mathrm{AA}}$ is performed as a function of transverse momentum $p_T$ in several centrality classes at forward rapidity ($2.5<y<4$) and midrapidity ($\left|y\right|<0.8$) for muons and electrons from heavy-flavour hadron decays, respectively. A suppression by a factor up to about 2.5 compared to the binary-scaled pp reference is observed in central collisions at both central and forward rapidities. The $R_{\mathrm{AA}}$ of muons from heavy-flavour hadron decays is compared to previous measurements in Pb–Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. When the nuclear modification factors are compared in the centrality classes 0–10% for Xe–Xe collisions and 10–20% for Pb–Pb collisions, which have similar charged-particle multiplicity density, a similar suppression, with $R_{\mathrm{AA}}\sim 0.4$ in the $p_T$ interval $4<p_T<8$ GeV/c, is observed. The comparison of the measured $R_{\mathrm{AA}}$ values in the two collision systems brings new insights on the properties of the quark-gluon plasma by investigating the system-size and geometry dependence of medium-induced parton energy loss. The results of muons and electrons from heavy-flavour hadron decays provide new constraints to model calculations.