Measurements of , , and Ξ⁺ + Ξ⁻ production in pp, pPb, and PbPb collisions with CMS

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• 作者：Hong Ni ; for the CMS Collaboration
• 关键词：CMS ; strange hadron ; spectra ; pp ; pPb ; PbPb ; radial flow
• 刊名：Nuclear Physics A
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：956
• 期：Complete
• 页码：449-452
• 全文大小：174 K

文摘

We present measurements of strange hadron ($K_s^0$, $\mathrm{\Lambda }+\bar{\mathrm{\Lambda }}$, and Ξ⁺+Ξ⁻${\mathrm{\Xi }}^{+}+{\mathrm{\Xi }}^{-}$) transverse momentum (p_T) spectra in pp, pPb, and PbPb collisions over a wide range in charge-particle multiplicity and particle rapidity. The data were taken with the CMS detector at the LHC for pp collisions at $\sqrt{s}=7\text{TeV}$, pPb collisions at $\sqrt{s_{NN}}=5.02\text{TeV}$, and PbPb collisions at $\sqrt{s_{NN}}=2.76\text{TeV}$. We find the average transverse kinetic energy (KE_T) increases with event multiplicity, with a faster rate for heavier particle species. At similar multiplicities, we observe the separation in the 〈KE_T〉$〈K{E}_T〉$, which is defined as 〈KE_T〉=〈m_T〉−m$〈K{E}_T〉=〈m_T〉-m$, where $m_T=\sqrt{m^2+p_T^2}$, between different particle species is larger for pp and pPb systems than PbPb system. In pPb collisions, 〈KE_T〉$〈K{E}_T〉$ is found to be larger in the Pb-going direction than in the p-going direction. This trend of asymmetry becomes more evident for heavier particle species as event multiplicity increases. We also compare the data to models motivated by hydrodynamics.