n uc l - th / 9 71 10 53 v 1 2 5 N ov 1 99 7 USC ( NT ) - 97 - 09 , nucl - th / 9711053 Chiral Perturbation Theory

n uc l - th / 9 71 10 66 v 1 2 8 N ov 1 99 7 nucl - th / 9711066 Thermal Model Analysis of Particle Ratios at GSI Ni – Ni Experiments Using

The production of hadrons in Ni–Ni at the GSI is considered in a hadronic gas model with chemical equilibrium. Special attention is given to the abundance of strange particles which are treated using the exact conservation of strangeness. It is found that all the data can be described using a temperature T = 70± 10 MeV and a baryon chemical potential μB = 720± 20 MeV. Typeset using REVTEX 1

ar X iv : n uc l - th / 9 71 10 31 v 1 1 8 N ov 1 99 7 HUPD - 9722 Effect of ρN channel in the γN → ππN reactions

ar X iv : n uc l - th / 9 71 10 28 v 1 1 4 N ov 1 99 7 A clue to the mechanism of Λ K + production in pp - reactions ∗

ar X iv : n uc l - th / 9 71 10 49 v 1 2 5 N ov 1 99 7 π + Emission from Hypernuclei and the Weak ∆

Low energy π emission in hypernuclear weak decays is related to ∆I = 3/2 part of nonmesonic weak decays according to the soft pion theorem. We show that neither meson exchange pictures nor virtual Σ excitation can solve the π emission puzzle. On the other hand, the direct quark mechanism gives the ratio R(π/π : S-wave, soft pion) ≈ 1/4 for 4ΛHe and 5ΛHe. ∗email: [email protected]

ar X iv : n uc l - th / 9 70 30 40 v 1 1 8 M ar 1 99 7 SUNY - NTG - 97 - 07 Strangeness production and flow in heavy - ion collisions

We study strangeness (K + , K − , and Λ) production and flow in Ni+Ni collisions at 1-2 AGeV, based on the relativistic transport model including the strangeness degrees of freedom. We find that strangeness spectra and flow are sensitive to the properties of strange hadrons in nuclear medium. The predictions of the chiral perturbation theory that the K + feels a weak repulsive potential and K −...