Double Collins effect in e+e- → Λ(Λ)over-barX and e+e- → ΛπX processes in a diquark spectator model

作者：Wang, Xiaoyu; Yang, Yongliang; Lu, Zhun^*

来源：PHYSICAL REVIEW D, 2018, 97(11): 114015.

DOI：10.1103/PhysRevD.97.114015

• SINGLE-SPIN ASYMMETRIES
• ODD FRAGMENTATION FUNCTIONS
• SIVERS ASYMMETRIES
• TRANSVERSE POLARIZATION
• HYPERON PRODUCTION
• STATE INTERACTIONS
• DRELL-YAN
• PROTON
• SIDIS
• PIONS

We study the Collins function H-1(perpendicular to) of the. hyperon, which describes the fragmentation of a transversely polarized quark into an unpolarized. hyperon. We calculate H-1(perpendicular to) for light quarks of the Lambda hyperon, in the diquark spectator model with a Gaussian form factor for the hyperon- quarkdiquark vertex. The model calculation includes contributions from both the scalar diquark and vector diquark spectators. Using the model result, we estimate the azimuthal asymmetry A(12), which appears in the ratio of unlike- sign events to like- sign events contributed by double Collins effects, in the processes e(+)e(-) -> Lambda(Lambda) over barX and e(+)e(-) -> Lambda pi X. The QCD evolution effects for the half kT moment of the Collins function and the unpolarized fragmentation function D-1(z) are also included. The results show that the asymmetries are sizable and measurable at the kinematical configurations of Belle and BABAR experiments. We also find that the evolution effects play an important role in the phenomenological analysis.

• 出版日期2018-6-11
• 单位东南大学