Measurement of prompt J/ψ and beauty hadron production cross sections at mid-rapidity in pp collisions at √s=7 TeV
Measurement of prompt J/ψ and beauty hadron production cross sections at mid-rapidity in pp collisions at √s=7 TeV
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DOI：
10.1007/jhep11(2012)065
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发表时间：
2012-11-01
影响因子：
5.4
通讯作者：
Zyzakbz, Maksym
中科院分区：
文献类型：
--
作者：
Abelev, Betty;Adam, Jaroslav;Zyzakbz, Maksym
大型强子对撞机上的ALICE实验通过电子对衰变研究了粒子碰撞中速产生的J/psi，这些电子对对应于积分光度L-INT=5.6nb(-1)。对于具有横向动量p(T)>；1，3GeV/c和快度垂直杆y垂直杆0.9的J/psi候选者，确定了来自长寿命美强子衰变的J/psi的分数。瞬发J/psi介子的截面，即直接产生的J/psi和较重碳态的瞬发衰变，例如psi(2S)和chi(C)共振，是sigma(瞬发J/psi)(p(T)>；1.3GeV/c，垂直条y垂直条形<；0.9)=8.3+/-0.8(统计)+/-1.1(系统)(-1.4)(+1.5)(系统。Pol.)在p(T)>；1.3GeV/c和垂直条形y垂直条形y<；0.9时，产生衰变到J/psi的b强子的截面为a sigma(J/psi 1.3GeV/c，垂直条形y垂直条形<；0.9)=1.46+/-0.38(统计)(-0.32)(+0.26)(系统.)结果与QCD模型的预测结果进行了比较。由微扰QCD模型计算得到的b夸克的p(T)和y分布的形状被用来外推测量的截面，以求出中快度下棒对总截面的b(B)和dσ/dy。
The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.