Transverse Λ polarization in e+e collisions

Leonard Gamberg, Zhong Bo Kang, Ding Yu Shao, John Terry, Fanyi Zhao

Research output: Contribution to journalArticlepeer-review

Abstract

In this paper we study transverse polarization of Λ hyperons in single-inclusive leptonic annihilation. We show that when the transverse momentum of the Λ baryon is measured with respect to the thrust axis, a transverse momentum dependent (TMD) factorization formalism is required and the polarization is generated by the TMD polarizing fragmentation function (TMD PFF), D1T. However, when the transverse momentum of the Λ baryon is measured with respect to the momentum of the initial leptons, a collinear twist-3 formalism is required and the polarization is generated by the intrinsic collinear twist-3 fragmentation function DT. Thus while these measurements differ from one another only by a change in the measurement axis, they probe different distribution functions. Recently, Belle measured a significant polarization in single-inclusive Λ baryon production as a function of the transverse momentum with respect to the thrust axis. However, this data can in principle be re-analyzed to measure the polarization as a function of the transverse momentum of the Λ baryon with respect to the lepton pair. This observable could be the first significant probe of the function, DT. In this paper, we first develop a TMD formalism for Λ polarization; we then present a recent twist-3 formalism that was established to describe Λ polarization. Using the TMD formalism, we demonstrate that the Λ polarization at OPAL and Belle can be described using the twist-2 TMD factorization formalism. Finally, we make a theoretical prediction for this polarization in the collinear twist-3 formalism at Belle.

Original languageEnglish (US)
Article number136371
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume818
DOIs
StatePublished - Jul 10 2021

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics

Fingerprint

Dive into the research topics of 'Transverse Λ polarization in e<sup>+</sup>e<sup>−</sup> collisions'. Together they form a unique fingerprint.

Cite this