Covariant model for Dalitz decays of decuplet baryons to octet baryons

Abstract

In the last years it became possible to measure in HADES the dilepton decays of several baryons. The baryon dilepton decays provide information about the electromagnetic structure of the baryons in the timelike region. In the present work, we study the B 0 → e þ e − B decays, where B 0 is a baryon decuplet member and B is a baryon octet member. Our calculations are based on the covariant spectator quark model, where the contribution of the quark core is complemented with an SUð3Þ contribution from the pion cloud. The pion cloud contribution prove to be relevant in the range of study. We present predictions for the Σ 0 ð1385Þ → e þ e − Λð1116Þ and Σ þ ð1385Þ → e þ e − Σ þ ð1193Þ decays, which may be tested at HADES in a near future. Predictions for the remaining decuplet baryon Dalitz decays are also presented. We conclude that different orders of magnitudes are expected for the baryon decuplet Dalitz decay widths, according to the quark content of the baryons. We also conclude that the dependence of the transition form factors on the square momentum transfer (q 2) is important for some transitions.

Electromagnetic transition form factors and Dalitz decays of hyperons

“…Again, it is nice to see how all angular dependence disappears for the cases where specific three-vectors vanish and therefore do not allow to define relative angles. For q 2 = (2m e ) 2 one can see directly how all angular dependence vanishes in the curly brackets of ( 22) and (23). For 2 this is achieved by the kinematical constraint (20).…”