论文标题
$ e^+e^ - \toλ^\ uparrow h x $进程TMD分解中的$λ$ hyperons的横向极化
The transverse polarization of $Λ$ hyperons in $e^+e^-\toΛ^\uparrow h X$ processes within TMD factorization
论文作者
论文摘要
我们研究了$ e^+e^ - \toλ^\uparrowπ^\ pm x $和$ e^+e^+e^ - \toλ^\ uparrow k^\ pm x $在横向动量依赖〜（tmd）因素的框架内。横向极化是由横向极化片段化函数的卷积〜（pff）$ d_ {1t}^\ perp $的lambda Hyperon和未溶解的片段化函数$ d_1 $ pion/kaon。我们采用$ d_ {1t}^{\ perp} $的观众diquark模型结果来估计Belle Collaporation在Kinematical Collocatoration $ e^+e^+e^ - \toλ^\ uparrow H x $过程中的横向极化。为了实现碎片函数的TMD进化形式主义，我们对与$λ$，pion和kaon的碎片函数相关的非扰动sudakov形式的形式应用了两个不同的参数化。据发现，我们对$λπ^+$生产的两极分化的预测和$ \barλπ^ - $与最近的Belle测量大小和标志的测量是一致的，而对$λπ^ - $和$λK^ - $ and $λk^\ pm $ PRODUCTION的模型预测显示出与Belle Data的强烈分歧。还讨论了差异的原因，并还讨论了将来改善计算的可能方法。
We investigate the transverse polarization of the $Λ$ hyperon in the processes $e^+e^-\toΛ^\uparrow π^\pm X$ and $e^+e^-\toΛ^\uparrow K^\pm X$ within the framework of the transverse momentum dependent~(TMD) factorization. The transverse polarization is contributed by the convolution of the transversely polarizing fragmentation function~(PFF) $D_{1T}^\perp$ of the lambda hyperon and the unpolarized fragmentation function $D_1$ of pion/kaon. We adopt the spectator diquark model result for $D_{1T}^{\perp}$ to numerically estimate the transverse polarization in $e^+e^-\toΛ^\uparrow h X$ process at the kinematical region of Belle Collaboration. To implement the TMD evolution formalism of the fragmentation functions, we apply two different parametrizations on the nonperturbative Sudakov form factors associated with the fragmentation functions of the $Λ$, pion and kaon. It is found that our prediction on the polarization in the $Λπ^+$ production and $\barΛ π^-$ is consistent with the recent Belle measurement in size and sign, while the model predictions on the polarizations in $Λπ^-$ and $ΛK^\pm$ productions show strong disagreement with the Belle data. The reason for the discrepancies is discussed and possible approaches to improve the calculation in the future are also discussed.
