Measurement of Spin Transfer Observables in Antiproton-Proton -> Antilambda-Lambda at 1.637 GeV/c

Abstract

Spin transfer observables for the strangeness-production reaction Antiproton-Proton -> Antilambda-Lambda have been measured by the PS185 collaboration using a transversely-polarized frozen-spin target with an antiproton beam momentum of 1.637 GeV/c at the Low Energy Antiproton Ring at CERN. This measurement investigates observables for which current models of the reaction near threshold make significantly differing predictions. Those models are in good agreement with existing measurements performed with unpolarized particles in the initial state. Theoretical attention has focused on the fact that these models produce conflicting predictions for the spin-transfer observables D_{nn} and K_{nn}, which are measurable only with polarized target or beam. Results presented here for D_{nn} and K_{nn} are found to be in disagreement with predictions from existing models. These results also underscore the importance of singlet-state production at backward angles, while current models predict complete or near-complete triplet-state dominance.

arXiv comment5 pages, 3 figures

References in corpus (5)

• THE PROTON SPIN PUZZLE AND DEPOLARIZATION IN $\bar{p}p\to \bar{\Lambda }\Lambda$
• Hadronic Probes of the Polarized Intrinsic Strangeness of the Nucleon
• A Quark Model of Antilambda-Lambda Production in Pbar-P Interactions
• Spin Observables in Antilambda-Lambda Production from Antiproton-Proton Annihilation with a Transverse Inital State Polarization
• Constraints on spin observables in antiproton-proton to antiLambda-Lambda

Cited by in corpus (8)

• Meson production in nucleon--nucleon collisions close to the threshold
• Experimental determination of the complete spin structure for anti-proton + proton -> anti-Λ+ Λat anti-proton beam momentum of 1.637 GeV/c
• Antiproton physics
• Weak Interaction Processes: Which Quantum Information is revealed?
• Today's View on Strangeness
• Polarization observables in low-energy antiproton-proton scattering
• Constraints on spin observables in pbar p --> Lambdabar Lambda
• Spin observables in antiproton-proton to AntiLambda-Lambda and density-matrix constraints