Measurement of electrons from semileptonic heavy-flavour hadron decays at midrapidity in pp and Pb-Pb collisions at √sNN=5.02 TeV
Measurement of electrons from semileptonic heavy-flavour hadron decays at midrapidity in pp and Pb-Pb collisions at √sNN=5.02 TeV
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测量 √sNN=5.02 TeV 下 pp 和 Pb-Pb 碰撞中半轻重味强子中速衰变的电子
DOI：
10.1016/j.physletb.2020.135377
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发表时间：
2020
影响因子：
4.4
通讯作者：
Shimomura M. and et al. for the ALICE Collaboration
中科院分区：
文献类型：
--
作者：
Acharya S.;Shimomura M. and et al. for the ALICE Collaboration
测量了半轻子重味强子衰变在中快度（0-10%）时微分不变产额与电子横动量（pT）的关系，在0.5-26 GeV/c的p-T间隔中，在sNN = 5.02 TeV的半中心（30-50%）和外围（60-80%）铅-铅（Pb-Pb）碰撞（0-10%和30-50%）和0.5-10 GeV/c（60-80%）。在0.5<pT < 10 GeV/c范围内测量了s= 5.02TeV的质子-质子（pp）碰撞的产生截面，在pT = 5GeV/c范围内，它接近微扰QCD计算不确定度的上带，在pT较大时接近平均值。修正的电子产额相对于预期的核子-核子碰撞的非相干叠加的评价通过测量核修改因子R AA。在不同的中心性类的测量的R AA允许在介质中的能量损失的魅力和美夸克进行调查。的R AA示出了抑制相对于统一在中间p T，这增加，而移动到更多的中心碰撞。此外，测量的R AA是敏感的修改的部分子分布函数（PDF）在核中，像核阴影，这会导致在LHC的重离子碰撞中的重夸克生产在低p T的抑制。
The differential invariant yield as a function of transverse momentum (p T) of electrons from semileptonic heavy-flavour hadron decays was measured at midrapidity in central (0–10%), semi-central (30–50%) and peripheral (60–80%) lead–lead (Pb–Pb) collisions at s NN= 5.02 TeV in the p T intervals 0.5–26 GeV/c (0–10% and 30–50%) and 0.5–10 GeV/c (60–80%). The production cross section in proton–proton (pp) collisions at s= 5.02 TeV was measured as well in 0.5< p T< 10 GeV/c and it lies close to the upper band of perturbative QCD calculation uncertainties up to p T= 5 GeV/c and close to the mean value for larger p T. The modification of the electron yield with respect to what is expected for an incoherent superposition of nucleon–nucleon collisions is evaluated by measuring the nuclear modification factor R AA. The measurement of the R AA in different centrality classes allows in-medium energy loss of charm and beauty quarks to be investigated. The R AA shows a suppression with respect to unity at intermediate p T, which increases while moving towards more central collisions. Moreover, the measured R AA is sensitive to the modification of the parton distribution functions (PDF) in nuclei, like nuclear shadowing, which causes a suppression of the heavy-quark production at low p T in heavy-ion collisions at LHC.