Ψ(2s)\Psi(2s) production in p+Ap+A collisions

We have analyzed the data on $\psi'$ production in proton-nucleus ($p+A$) collisions, available from the NA50 Collaboration in the SPS energy domain. The investigated data sets include the absolute production cross sections as well as $\psi'$-to-Drell Yan (DY) cross section ratios. An adapted version of two component QVZ model has been employed to calculate $\psi'$ production cross sections. For both $\psi'$ and DY production, nuclear modifications to the free nucleon structure functions are taken into account. For $\psi'$, final state interaction of the produced $c\bar{c}$ pairs with the nuclear medium is also taken into account, in accordance with the previously analyzed $J/\psi$ data. A satisfactory description of the data in $p+A$ collisions is obtained. Model calculations are extrapolated to low energy regime to predict the $\psi'$ suppression in proton induced collisions at near threshold energies.Comment: 6 pages, 14 figures. Extensively revised, new figures adde

Quadrupole deformation in Λ\Lambda-hypernuclei

Shapes of light normal nuclei and $\Lambda$-hypernuclei are investigated using relativistic mean field approach. The FSUGold parametrization is used for this purpose. The addition of a $\Lambda$ is found to change the shape of the energy surface towards prolate. The deformation in a $\Lambda$-hypernucleus, when the hyperon is in the first excited state, is also discussed. The effect of the inclusion of the hyperon on the nuclear radius is generally small with one exception

QCD phase transition in rotaing neutron star, Neutrino beaming and Gamma-ray bursters

We have studied the emission of neutrinos from a rotating hybrid star. We find that the emission is predominantly confined to a very small angle, provided the core of the star is in a mixed phase of quarks and hadrons and the size of such a mixed phase is small. Annihilation of neutrinos to produce gamma rays has been discussed. The estimated duration of the burst is found to be within the observational range.Comment: Modified manuscript with 9 pages including 3 ps figures, Accepted for publication in Phys. Lett.