Maryam Hassanvand, Seyed Zafarollah Kalantari, Yoshinori Akaishi, Toshimitsu Yamazaki
We formulated the Lambda(1405) (abbreviated as Lambda^*) --> (Sigma pi)^0 invariant-mass spectra produced in p+p --> p + Lambda^* + K^+ reactions, in which both the incident channel for a quasi-bound K^-p state and its decay process to (Sigma pi)^0 were taken into account realistically. We calculated M(Sigma pi) spectral shapes for various theoretical models for Lambda^*. They are asymmetric and skewed, and were compared with recent experimental data of HADES, yielding M(Lambda^*) = 1405 -9 +11 MeV/c^2 and Gamma = 62 +- 10 MeV. The nearly isotropic proton distribution observed in DISTO and HADES is ascribed to a short collision length in the production of Lambda^*, which justifies the high sticking mechanism of Lambda^* and the participating proton into K^-pp.
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http://arxiv.org/abs/1210.7725
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