We explore how chiral-symmetry constraints on weak-interaction matrix elements suggest the existence of an intermediate-state σ in several different weak-interaction processes. Particular attention is directed toward recent evidence for a σ within three-body nonleptonic weak decays. The existence of a broad scalar-isoscalar ππ resonance near 500-600 MeV, the σ, has long been controversial. Afte...

We study the high frequency limit for a non-dissipative Helmholtz equation. We first prove the absence of eigenvalue on the upper half-plane and close to an energy which satisfies a weak damping assumption on trapped trajectories. Then we generalize to this setting the resolvent estimates of Robert-Tamura and prove the limiting absorption principle. We finally study the semiclassical measures o...

I review the current status of understanding the mechanism of the nonmesonic weak decays (NMWD) of hypernuclei. Long standing problem on the Γnn/Γpn ratio has been solved by considering short-range weak interactions properly. This leaves a few remaining problems, such as the asymmetry of the emitted proton with respect to the Λ polarization and validity of the ∆I = 1/2 in the nonmesonic weak de...

Bruno Pontecorvo was a great physicist who had enormous impact on the development of neutrino physics. He was charming, marvelous person. I worked with B. Pontecorvo in Dubna about 15 years and during these years we were connected by warm, friendly relations. I this talk I will speak about major contributions of Bruno Pontecorvo to neutrino physics and I will try to convey my impression about h...

Wigner and Husimi transforms have long been used for the phasespace reformulation of Schrödinger-type equations, and the study of the corresponding semiclassical limits. Most of the existing results provide approximations in appropriate weak topologies. In this work we are concerned with semiclassical limits in the strong topology, i.e. approximation of Wigner functions by solutions of the Liou...

the charge transfer (ct) complex formation of benzonitrile as acceptor with the aromatic donors o-, m-, p-xylene and ethylbenzene in ccl4 solutions is investigated by chemical shift measurements relative to an external reference. the equilibrium parameters, q and dad of their weak molecular complexes, as found numerically modified cresswel- allred (c-a) method, is compared with graphically scat...