论文标题
关于PP碰撞中包容性J/$ψ$生产的非贡献贡献的两极分化
On the polarization of the non-prompt contribution to inclusive J/$ψ$ production in pp collisions
论文作者
论文摘要
在PP碰撞中产生的J/$ψ$介子（包括B衰变的很大一部分），随横向动量增加，超过50 \％，对于$ p _ {\ rm t}> 20 $ gev。这些事件必须在迅速j/$ψ$介子的极化的测量中减去这些事件。虽然几项研究已经解决了$ψ$（2s）和$χ_c$对直接生产的J/$ψ$ Meson的两极化的确定影响，但对非预测极化的理论和实验知识非常差。此外，非预测J/$ψ$极化测量值可以提供有关五夸昆顿五生生物生产的有趣信息，从而补充了及时生产的研究。我们回顾了测量非预测J/$ψ$介子（在未结构的B介子腐烂中生产并在Dilepton通道中检测到的）的方法，在研究J/$ψ$产生的LHC实验的典型条件下。通过研究$ e^+e^ - \ to到υ$（4S）相互作用的实验的数据，对现实模型独立的方案进行了验证，并使用在LHC上测得的差异横截面转换为高摩诺特机制。即使在纠正DILEPTON的接受度和效率之后，也可以认为非预测J/$ψ$极化测量仍然取决于事件选择标准。这意味着所有相关分析选择的可再现定义必须与极化结果报告，以与其他测量和/或理论计算进行严格的比较。 We also discuss how the non-prompt J/$ψ$ polarization significantly depends on the relative importance of two complementary $\mathrm{B}\to {\rm J}/ψ$ decay topologies, two-body (reasonably dominated by singlet production) and multi-body (including octet contributions), providing, hence, valuable information for studies of the charmonium formation mechanisms.
Of the J/$ψ$ mesons (inclusively) produced in pp collisions, a big fraction results from B decays, increasing with transverse momentum and exceeding 50\% for $p_{\rm T} > 20$ GeV. These events must be subtracted in measurements of the polarization of prompt J/$ψ$ mesons. While several studies have addressed the $ψ$(2S) and $χ_c$ impact on the determination of the polarization of the directly-produced J/$ψ$ mesons, the theoretical and experimental knowledge of the non-prompt polarization is very poor. Furthermore, non-prompt J/$ψ$ polarization measurements can provide interesting information on quarkonium hadroproduction, complementing the studies of prompt production. We review the method of measuring the polarization of non-prompt J/$ψ$ mesons (produced in decays of unreconstructed B mesons and detected in the dilepton channel), in conditions typical of LHC experiments studying J/$ψ$ production. Realistic model-independent scenarios are validated with data from experiments studying $e^+e^- \to Υ$(4S) interactions, converted to the high-momentum regime using B differential cross sections measured at the LHC. The non-prompt J/$ψ$ polarization measurements are seen to remain dependent on the event selection criteria, even after correcting for the dilepton acceptance and efficiencies. This implies that reproducible definitions of all relevant analysis choices must be reported with the polarization result, for rigorous comparisons with other measurements and/or theoretical calculations. We also discuss how the non-prompt J/$ψ$ polarization significantly depends on the relative importance of two complementary $\mathrm{B}\to {\rm J}/ψ$ decay topologies, two-body (reasonably dominated by singlet production) and multi-body (including octet contributions), providing, hence, valuable information for studies of the charmonium formation mechanisms.
