Measurement of the charged-hadron spectra and nuclear modification factor in lead-lead collisions with the ATLAS detector

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• 作者：Petr Balek ; for the ATLAS Collaboration
• 关键词：lead&ndash ; lead collisions ; nuclear modification factor
• 刊名：Nuclear and Particle Physics Proceedings
• 出版年：2016
• 出版时间：July-September 2016
• 年：2016
• 卷：276-278
• 期：Complete
• 页码：317-320
• 全文大小：235 K

文摘

The ATLAS experiment at the Large Hadron Collider (LHC) measures charged hadron spectra obtained in 2010 and 2011 lead–lead LHC data taking periods with total integrated statistics of 0.15 nb⁻¹. The results are compared to the pp spectra of charged hadrons at the same centre-of-mass energy based on the data sample with integrated luminosity of 4.2 pb⁻¹ obtained by the ATLAS experiment in 2011 and 2013. This allows a detailed comparison of the two collision systems in a wide transverse momentum (0.5<p_T<150 GeV$0.5<p_{\mathrm{T}}<150\text{GeV}$) and pseudorapidity (|η|<2$|\eta |<2$) ranges in different centrality intervals of Pb+Pb collision. The nuclear modification factor R_AA is presented in detail as a function of centrality, p_T and η. It shows a distinct p_T-dependence with a pronounced minimum at about 7 GeV. Above 60 GeV, it is consistent with a flat, centrality-dependent, value within the uncertainties. The value is 0.55±0.01(stat)±0.04(mathitsyst.)$0.55\pm 0.01(\mathit{stat})\pm 0.04(mathitsyst.)$ in the most central collisions. The R_AA is observed to be consistent with flat |η| dependence over the whole transverse momentum range in all centrality classes.