Production of Muons from Heavy Flavor Decays at Forward Rapidity in $pp$ and Pb-Pb Collisions at $\sqrt{s_{NN}}\mathbf{=}2.76\mathrm{TeV}$

The ALICE Collaboration has measured the inclusive production of muons from heavy-flavor decays at forward rapidity, $2.5<y<4$, in $pp$ and Pb-Pb collisions at $\sqrt{s_{NN}}=2.76\mathrm{TeV}$. The $p_t$-differential inclusive cross section of muons from heavy-flavor decays in $pp$ collisions is compared to perturbative QCD calculations. The nuclear modification factor is studied as a function of $p_t$ and collision centrality. A weak suppression is measured in peripheral collisions. In the most central collisions, a suppression of a factor of about 3–4 is observed in $6<p_t<10\mathrm{GeV}/c$. The suppression shows no significant $p_t$ dependence.

Figure 1

Transverse momentum differential inclusive cross section of muons from heavy-flavor decays in $2.5<y<4$, in $pp$ collisions at $\sqrt{s}=2.76\mathrm{TeV}$. The vertical error bars (open boxes) are the statistical (systematic) uncertainties. The solid curve and the band show FONLL [27, 28] calculations and theoretical uncertainties, respectively. The FONLL calculations are also reported for muons from charm (long dashed curves) and beauty (dot-dashed curves) decays, separately. The lower panel shows the ratio between data and FONLL calculations.

Figure 2

$R_{AA}$ of muons from heavy-flavor decays in $2.5<y<4$ as a function of $p_t$, in the 0–10% (left) and 40%–80% (right) centrality classes, in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76\mathrm{TeV}$. Vertical bars (open boxes) represent the statistical (systematic) uncertainty. The filled box centered at $R_{AA}=1$ is the normalization uncertainty. Horizontal bars show the bin widths.

Figure 3

$R_{AA}$ of muons from heavy-flavor decays as a function of the mean number of participating nucleons, in $2.5<y<4$ and $6<p_t<10\mathrm{GeV}/c$. The horizontal bars indicate the uncertainty on $⟨N_{\mathrm{part}}⟩$.