Radiative and Meson Decays of Y(4230) in Flavor SU(3)

The charmonium-like exotic states Y(4230) and the less known Y(4320), produced in e+e− collisions, are sources of positive parity exotic hadrons in association with photons or pseudoscalar mesons. We analyze the radiative and pion decay channels in the compact tetraquark scheme, with a method that proves to work equally well in the most studied D∗→γ/π+D decays. The decay of the vector Y into a pion and a Zc state requires a flip of charge conjugation and isospin that is described appropriately in the formalism used. Rates are found to depend on the fifth power of pion momentum, which would make the final states πZc(4020) strongly suppressed with respect to πZc(3900). The agreement with BES III data would be improved considering the πZc(4020) events to be fed by the tail of the Y(4320) resonance under the Y(4230). These results should renovate the interest in further clarifying the emerging experimental picture in this mass region.

Signature of Λ(1405) resonance in K− +6Li reaction

We investigate whether the mass and momentum spectra of emitted particles in [Formula: see text] reaction can be used for disentangling the nature of [Formula: see text](1405) and how the signature of the [Formula: see text](1405) resonance appears in the cross-sections of the kaon-lithium reaction on the physical real energy. We used different types of [Formula: see text] potentials to study the dependence of the results to the fundamental kaon-nucleon interaction. The momentum spectra are calculated for final pions and neutrons. The possibility of the observation of the [Formula: see text](1405) resonance in the mass spectra is studied. It was demonstrated that the [Formula: see text] mass and neutron momentum spectra are more suitable than the pion momentum spectra to see the trace of the [Formula: see text](1405) resonance and it is a useful tool for investigating the subthreshold behavior of the [Formula: see text] interaction.

CHARGE INDEPENDENCE BREAKING IN MESON PRODUCTION?

We investigate by global and local fits whether existing data on pp → π+d and np → π0d have indications on charge dependent forces other than the Coulomb force and the effect of differing thresholds. We find evidence in the energy (or pion momentum) dependence of the total cross sections close to threshold.

The exclusive reaction of pion quasi-elastic knockout from nucleon p(e, e′ π)B to various states of the final baryon-spectator B and the quark models for the pion cloud of nucleon

The pion momentum distributions (MDs) in four channels of virtual decay p→B+π, B = N, Δ, N 1/2-(1535), N 1/2+(1440) are calculated in two models, the microscopic model of 3 P 0 scalar q−q fluctuation with the pion as a composite q−q-system and the chiral semi-microscopic model of πq interaction with the pion as a structureless Goldstone boson. The results of the above models are similar for the baryon states B = N, Δ, N 1/2-(1535) but are rather different for the Roper resonance N 1/2+(1440) which corresponds to excitation of two oscillator quanta in the nucleon. The experimental investigation of pion MDs by means of the reaction of quasi-elastic knockout of pion by an electron of a few GeV energy p(e, e′ π)B may be very suitable for Jefferson Laboratory, Virginia (JLab).

PARTITION TEMPERATURE AND PION CONDENSATION IN HIGH ENERGY COLLISIONS

We develop a description of single pion momentum distributions incorporating Bose-Einstein statistics and compare it to data at ISR and collider energies. Events of fixed multiplicity are described by a temperature which varies as a function of multiplicity. For high temperatures the model gives similar results to the recently introduced partition temperature model. while for low temperatures the possibility of pion condensation is explored.