X iv : n uc l - th / 9 71 10 52 v 1 2 5 N ov 1 99 7 Delta excitation in K + - nucleus collisions

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 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 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 00 32 v 1 1 4 O ct 1 99 7 K + production in baryon - baryon and heavy - ion collisions

Kaon production cross sections in nucleon-nucleon, nucleon-delta and delta-delta interactions are studied in a boson exchange model. For the latter two interactions, the exchanged pion can be on-mass shell, only contributions due to a virtual pion are included via the Peierls method by taking into account the finite delta width. With these cross sections and also those for pion-baryon interacti...

ar X iv : n uc l - th / 9 71 10 39 v 2 2 4 N ov 1 99 7 Collective flow in central Au – Au collisions at 150 , 250 and 400 A MeV

Spherical collective flow and thermalization are studied in gold on gold collisions at 150, 250 and 400 A MeV bombarding energies with a relativistically covariant formulation of a QMD code [1]. We find that spherical flow and thermal energies calculated for all the charged fragments agree reasonably with the experimental values [2]. The experimental cut at small angles used in the FOPI experim...