Production of $^{4}$He and anti-$^{4}$He in Pb--Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV at the LHC

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2.76 TeV
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We present results on the production of $^{4}$He and $^{4}\overline{\textrm{He}}$, determined using the ALICE detector in central (0-10\%) Pb--Pb collisions at $ \sqrt{s_{\mathrm{NN}}} = 2.76 $ TeV. The resulting rapidity densities are $\mathrm{d}N/\mathrm{d}y _{(^{4}\mathrm{He})} = 7.3 \times 10^{-7} \pm 3.3 \times 10^{-7}~(stat.) \pm 2.5 \times 10^{-7}~(syst.)$ and $\mathrm{d}N/\mathrm{d}y _{(^{4}\mathrm{\overline{He}})} = 1.0 \times 10^{-6} \pm 0.3 \times 10^{-6}~(stat.) \pm 0.2 \times 10^{-6}~(syst.)$, respectively. This is in agreement with the statistical thermal model expectation assuming the same temperature ($T_{\mathrm{chem}}$ = 156 MeV) as for the hadrons. The ratio of $^{4}\overline{\mathrm{He}}$/$^{4}$He is determined to be $1.4 \pm 0.8~(stat.) \pm 0.5~(syst.)$.