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arXiv 1809.04038hep-phhep-exnucl-ex
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$e^+e^-$湮灭为重子-反重子对的极化观测量

Polarization observables in $e^+e^-$ annihilation to a baryon-antibaryon pair

Elisabetta Perotti, Göran Fäldt, Andrzej Kupść, Stefan Leupold, Jiao Jiao Song

摘要:

利用Jacob和Wick的螺旋度理论,我们导出了$e^+e^-$湮灭过程中产生的重子反重子对的自旋密度矩阵.我们考虑自旋为$1/2+\overline{1/2}$,$1/2+\overline{3/2}$(+c.c.)和$3/2+\overline{3/2}$。我们提供模块表达式,包括链的弱强子两体衰变的超子。该表达式适用于分析在$e^+e^-$对撞机上$J/ψ$和$ψ(2S)$衰变的高统计数据,并与被测粒子的全微分角分布相拟合。我们举例说明的方法,如包容性测量的$e^+e^-\toψ(2S)\toΩ^-\barΩ^+$过程中,一个衰变链$Ω^-\toΛK^-$其次是$Λ\to pπ^-$被认为是。最后,我们证明了包容角分布可以用来检验所产生的重子的自旋指定。

英文摘要:

Using the helicity formalism of Jacob and Wick we derive spin density matrices of baryon antibaryon pairs produced in $e^+e^-$ annihilation. We consider the production of pairs with spins $1/2+\overline{1/2}$, $1/2+\overline{3/2}$ (+c.c.) and $3/2+\overline{3/2}$. We provide modular expressions to include chains of weak hadronic two-body decays of the produced hyperons. The expressions are suitable for the analysis of high statistics data from $J/ψ$ and $ψ(2S)$ decays at $e^+e^-$ colliders, by fits to the fully differential angular distributions of the measured particles. We illustrate the method by examples, such as the inclusive measurement of the $e^+e^-\toψ(2S)\toΩ^-\barΩ^+$ process where one decay chain $Ω^-\toΛK^-$ followed by $Λ\to pπ^-$ is considered. Finally we show that the inclusive angular distributions can be used to test spin assignment of the produced baryons.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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