Anti-Lambda polarization in high energyppcollisions with polarized beams

Abstract

We study the polarization of the anti-Lambda particle in polarized high energy pp collisions at large transverse momenta. The anti-Lambda polarization is found to be sensitive to the polarization of the anti-strange sea of the nucleon. We make predictions using different parameterizations of the polarized quark distribution functions. The results show that the measurement of longitudinal antiLambda polarization can distinguish different parameterizations, and that similar measurements in the transversely polarized case can give some insights into the transversity distribution of the anti-strange sea of nucleon.

Antihyperon polarization in high energyppcollisions with polarized beams

“…[32] are shown in Fig. 7, together with our previous results for PΛ [26]. The main characteristics are:…”

“…Phenomenological studies of longitudinal hyperon polarization may be found in Refs. [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]. The main themes of these studies can be categorized as follows.…”

“…The proton spin physics program at the Relativistic Heavy Ion Collider (RHIC) has come online [28]. A recent study for anti-Lambda polarization in polarized pp collisions [26] shows sensitivity to the anti-strange quark spin contribution to the proton spin, which is only poorly constrained by existing data. In this paper, we evaluate the longitudinal polarization of theΣ − ,Σ + ,Ξ 0 andΞ + anti-hyperons in pp collisions at large transverse momenta p T .…”

Recent results of the STAR high-energy polarized proton-proton program at RHIC at BNL

“…The measurement of D LL for inclusive Λ andΛ production may provide constraints on strange (anti) quark polarization [35] and can yield new insight into polarized fragmentation functions [36]. The extension of the p T region to large values is essential.…”

Measurement of the longitudinal spin transfer to Λ and $\bar{\varLambda}$ hyperons in polarised muon DIS

“…The spin transfer to Λ andΛ hyperons has been studied extensively in a number of theoretical models [6][7][8][9][10][11][12][13][14] for e + e − collisions and lepton DIS. From a theoretical point of view the simplest case is the polarisation of the hyperons formed in e + e − annihilation at the Z-peak, where the hadronisation of the qq-system can be well described using independent fragmentation.…”