Baryonic resonances close to the Kbar-N threshold: the case of Lambda(1405) in pp collisions
Keywords
INSPIRE: anti-K nucleon: threshold, cross section: measured, angular distribution, p p: scattering, Lambda(1405): hadronic decay, baryon resonance: hadroproduction, HADES, Lambda(1520): intermediate state, Sigma(1385): intermediate state, Delta(1232)_s16_s16: intermediate state, channel cross section, experimental results, Darmstadt SIS, p p --> Sigma p K pi, Lambda(1405) --> Sigma pi, Sigma --> n pi, 3.5 GeV-kin
Abstract
We present an analysis of the Lambda(1405) resonance produced in the reaction p_s16p->Sigma^{pm}_s16pi^{mp}_s16K_s16p at 3.5 GeV kinetic beam energy measured with HADES at GSI. The two charged decay channels Lambda(1405) -> Sigma^{pm}_s16pi^{mp} have been reconstructed for the first time in p_s16p collisions. The efficiency and acceptance-corrected spectral shapes show a peak position clearly below 1400 MeV/c^2. We find a total production cross section of sigma_{Lambda(1405)}=9.2 _s16- 0.9 _s16- 0.7 _s163.3-1.0 mub. The analysis of its polar angle distribution suggests that the Lambda(1405) is produced isotropically in the p-p center of mass system.
