### Energy dependence of the *Lambda*/*Sigma*^{0}
production cross section ratio in *p*-*p*
interactions

### Abstract

The production of the *Lambda* and *Sigma*^{0}
hyperons has been measured via the
*pp->pK*^{+}Lambda / Sigma^{0}
reaction at the internal COSY-11 facility in the excess energy
range between 14 and 60 MeV.
The transition of the *Lambda / Sigma*^{0}
cross section ratio from about 28 at Q <= 13 MeV
to the high energy level of about 2.5 is covered by the data
showing a strong decrease of the ratio between 10 and 20 MeV
excess energy.

The strength of the final state interactions in the
*p-Sigma*^{0} channel seems to be much smaller
compared to the *p-Lambda* one.
Estimates of the effective range parameters are given for the
*N Lambda* and the *N Sigma*^{0}
systems.

Preprint in
PostScript format (415kB)

E-print:
http://xxx.lanl.gov/abs/nucl-ex/0402008

Eur.Phys.Jou. A
22
(2004)
293-299