J. Sánchez Guillén

Integrable chiral theories in 2 + 1 dimensions

Following a recent proposal for integrable theories in higher dimensions based on zero curvature, new Lorentz invariant submodels of the principal chiral model in 2 + 1 dimensions are found. They have infinite local conserved currents, which are explicitly given for the su(2) case. The construction works for any Lie algebra and in any dimension, and it is given explicitly also for su(3). We comment on the application to supersymmetric chiral models.

Weak meson decays in a quark current×current picture with symmetry breaking

SummaryStarting from the Cabibbo weak current in the framework of the relativistic quark model an effective current is deduced. It includesSU3 breaking via the quark mass differences. The following decays are considered: K → μν, π+ → π0eν, K → πμν, K+ → π+π0 and Ks0 → 2π. The computations are parameter-free and agreement with experiment is achieved.RiassuntoSi desume una corrente efficace a partire dalla corrente debole di Cabibbo nell’ambito del modello relativistico a quark. Essa comprende la rottura della simmetriaSU3 per mezzo della differenza delle masse dei quark. Si prendono in considerazione i seguenti decadimenti: K → μν, π+ → π0eν, K → πμν, K+ → π+π0 e Ks0 → 2π. Si hanno dei calcoli senza parametri e si ottiene un buon accordo con gli esperimenti.РеэюмеИсходя иэ слабого тока Кабиббо, в рамках релятивистской модели кварков выводится зффективный ток. При рассмотрении учутывается нарущениеSU3 череэ раэности масс кварков. Исследуются следуюшие распады K → μν, π+ → π0eν, K → πμν, K+ → π+π0 и Ks0 → 2π. Вычисления не содержат свободных параметров и получается хорощее согласие с зкспериментом.(*) Переведено редакцией.

On QCD and valence-quark approximation for non-leptonic decays of baryons

Abstract In the valence-quark approximation relevant for the QCD approach to hadronic weak decays, we consider all quark diagrams directly, without soft pions. The analysis tests the consistency of the approximation and is in qualitative agreement with previous estimates for S-waves, but it has new predictions, which for the P-waves of Σ − − and Ω → Λ K indicate a clear conflict between aspects of the standard approach and experiment.

Quark forces and SU(6) configuration mixing

Symmetry breaking through SU(6) configuration mixing is investigated, considering low-energy weak and electromagnetic processes and the relations to one-gluon-exchange potentials. We find evidence against

Evidence for higher twist from R= sigma L/ sigma T data in deep-inelastic electron scattering.

d

Lifetimes of charmed baryons

waves in nucleons and the possibility of an antisymmetric

On the mass splitting of the charmed mesons

p

Analysis of CP violation through phase angles in weak charged currents in a relativistic quark model

-wave component.