- th / 9 70 70 22 v 2 1 4 D ec 1 99 7 The quark - meson coupling model for Λ , Σ and Ξ hypernuclei

- th / 9 70 70 22 v 1 1 6 Ju l 1 99 7 The quark - meson coupling model for Λ , Σ and Ξ hypernuclei

The quark-meson coupling (QMC) model, which has been successfully used to describe the properties of both infinite nuclear matter and finite nuclei, is applied to a systematic study of Λ, Σ and Ξ hypernuclei. Assumptions made in the present study are, (i) the (self-consistent) exchanged scalar, and vector, mesons couple only to the u and d quarks, and (ii) an SU(6) valence quark model for the b...

th / 0 30 30 73 v 2 4 J un 2 00 4 Λ + c , Σ c , Ξ c and Λ b hypernuclei in the quark - meson coupling model

th / 0 30 30 73 v 3 6 S ep 2 00 4 Λ + c , Σ c , Ξ c and Λ b hypernuclei in the quark - meson coupling model

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 : h ep - p h / 98 12 42 4 v 1 1 8 D ec 1 99 8 Nontriviality of the Linear Sigma Model

We consider techniques (based on an ultraviolet cutoff) used to prove that the pure boson (φ 4) 4 field theory is trivial and apply them instead to the dynamically generated quark-level linear sigma model. This cutoff approach leads to the conclusion that the latter field theory is in fact nontrivial. Owing to the recent observational identification [1] of a nonstrange scalar σ meson below 1 Ge...