A ′ 2 and proton-nucleus Drell-Yan cross-section ratios σ pA DY /σ pA ′ DY in order to determine optimum parton distribution functions (PDFs) in nuclei. An important point of this analysis is to show uncertainties of the distributions by the Hessian method. The results indicate that the uncertainties are large for gluon distributions in the whole x region and for antiquark distributions at x > ...

The renormalization group flow in the theory space of a BRST invariant string σ-model is investigated. For the open bosonic string the non-perturbative off-shell effective action and its gauge symmetry properties are determined from β-functions defined by the local Weyl anomaly. The interactions are shown to explicitly break the free theory BRST invariance generating new non-linear gauge symmet...

Neutrino processes in dense matter play a key role in the dynamics, deleptonization and the early cooling of hot protoneutron stars formed in the gravitational collapse of massive stars. Here we calculate neutrino mean free paths from neutrino-hyperon interactions in dense matter containing hyperons. Significant contributions to the neutrino opacity arise from scattering involving the Σ− hypero...

The riddle of the σ is recast in a way that tries to differentiate fact from fiction as a basis for future/further discussion. By doing this, it is hoped that the role of the σ as dominating the ubitiquitous ππ interactions below 1 GeV and its relation to the QCD vacuum can be clarified. In this talk, I will start to answer some of the questions that Lucien Montanet listed in his introduction a...

We consider zero-temperature, stochastic Ising models σ with nearest-neighbor interactions and an initial spin configuration σ0 chosen from a symmetric Bernoulli distribution (corresponding physically to a deep quench). Whether σ∞ exists, i.e., whether each spin flips only finitely many times as t → ∞ (for almost every σ0 and realization of the dynamics), or if not, whether every spin — or only...

We consider meson-baryon interactions in S-wave with strangeness −1. This is a nonperturbative sector populated by plenty of resonances interacting in several two-body coupled channels. We study this sector combining a large set of experimental data. The recent experiments are remarkably accurate demanding a sound theoretical description to account for all the data. We employ unitary chiral per...

Numerous theoretical and experimental arguments are presented in favor of the generation of intermediate σ-dressed dibaryon in NN interaction at intermediate and short distances. We argue that this intermediate dibaryon can be responsible for the strong intermediate-range attraction and the short-range repulsion in the NN interaction, and also for the short-range correlations in nuclei. The sug...

COSY with a maximum beam momentum of ∼ 3.65 GeV/c allows the production of ground state (Λ and Σ) and excited hyperons (Λ(1405), Σ(1385) and Λ(1520) ) in elementary NN interactions. The existing data base in this field is rather poor. A systematic study of the hyperon production at COSY will result in an improvement of our understanding concerning topics like hyperon–nucleon interaction, kaon–n...

Finite–size scaling properties and Casimir forces in an exactly solvable quantum statistical–mechanical model Abstract A d–dimensional finite quantum model system confined to a general hypercubical geometry with linear spatial size L and " temporal size " 1/T (T-temperature of the system) is considered in the spherical approximation under periodic boundary conditions. Because of its close relat...