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arXiv 2311.04462hep-phhep-ex
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衰变对奇宇称碎裂函数的贡献

The decay contribution to the parity-odd fragmentation functions

Yan-Lei Pan, Kai-Bao Chen, Yu-Kun Song, Shu-Yi Wei

AI总结:

本文研究弱衰变对奇宇称碎裂函数的贡献,计算其对背对背双强子产生中可观测量的影响,并数值展示该贡献显著,为识别强宇称破坏项提供重要背景。

摘要:

QCD中的宇称破坏是所谓的QCD $\ heta$-真空的结果。因此,引入了奇宇称碎裂函数,它们在$e^+e^-$湮灭实验中的背对背双强子产生中带来了新的可观测量[Phys.Rev.Lett. 106 (2011) 042001]。对相应奇宇称碎裂函数的实验测量可以揭示QCD中的局域CP破坏效应。另一方面,弱相互作用也破坏宇称对称性。因此,较重强子的弱衰变也可以对碎裂函数中的奇宇称效应做出贡献。在本文中,我们研究了弱衰变对这些奇宇称碎裂函数的贡献,并计算了它们对这些新可观测量的贡献。原则上,衰变贡献在理论分析和实验测量中应该/可以被排除。然而,到目前为止这通常不是普遍做法。此外,鉴于$\ heta$参数的值极小($\ heta< 3 \ imes 10^{-10}$),弱宇称破坏贡献成为识别强宇称破坏项的重要背景。在本文中,我们聚焦于奇宇称碎裂函数的弱衰变贡献,并通过数值估计展示其可观的贡献。

英文摘要:

Parity violation in QCD is a consequence of the so-called QCD $θ$-vacuum. As a result, parity-odd fragmentation functions are introduced and they bring in new observables in the back-to-back dihadron productions in $e^+e^-$-annihilation experiments [Phys.Rev.Lett. 106 (2011) 042001]. The experimental measurements on the corresponding parity-odd fragmentation functions can shed light on the local CP violation effect in QCD. On the other hand, the weak interaction also violates the parity symmetry. Therefore, the weak decay of heavier hadrons can also contribute to the parity-odd effects in fragmentation functions. In this paper, we investigate the weak decay contribution to these parity-odd fragmentation functions and compute their contribution to these new observables. In principle, the decay contribution should/can be excluded in the theoretical analysis and experimental measurements. However, this is usually not the common practice so far. Furthermore, in light of that the value of the $θ$-parameter is extremely small ($θ< 3 \times 10^{-10}$), the weak-parity-violating contributions become an important background in identifying the strong-parity-violating term. In this paper, we focus on the weak decay contribution of parity-odd fragmentation functions and demonstrate their sizable contribution in a numerical estimate.

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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