Application of Straw Tube Detectors to Hyperon Studies

摘要

A high statistics measurement of the (p) over right arrowp -> pK(+)Lambda reaction was done with the COSY-TOF experiment. The proton beam was polarized up to more than 80%, and its momentum was 2.95 GeV/c. The reconstruction of the pK(+)Lambda events was done only with the straw tube tracker due to the higher spatial resolution of the straw tube tracker compared to other subdetectors. The Dalitz plot of the pK(+)Lambda events was analyzed to understand the reaction mechanism and presented in this paper. The Dalitz plot shows that the COSY-TOF experiment provides complete kinematic coverage of the phase space of this reaction which made it ideal for (p) over right arrowp -> pK(+)Lambda reaction analysis. The influence of different physical effects as p Lambda final state interaction, excited nucleon states (N*-resonances) and a coupled channel effect of N Sigma-p Lambda (N Sigma cusp effect) produce significant structures in the Dalitz plot. The angular distribution of the particles in the CMS and helicity frame was also presented in this paper.