118955676
Phase transition in a statistical model for nuclear multifragmentation
We use a simplified model which is based on the same physics as inherent in most statistical models for nuclear multifragmentation. The simplified model allows exact calculations for thermodynamic properties of systems of large number of particles. This enables us to study a phase transition in the model. A first order phase transition can be tracked down. There are significant differences between this phase transition and some other well-known cases. {copyright} {ital 1998} {ital The American Physical Society}
2820708
Transverse momenta, nuclear equation of state, and momentum-dependent interactions in heavy-ion collisions.
We investigate the generation of transverse momentum in high-energy heavy-ion collisions and its relation to the nuclear equation of state. We find that streamer chamber data can be fitted by Boltzmann-Uehling-Uhlenbeck calculations with a momentum-dependent potential that closely models realistic nuclear matter interactions and yields an equation of state with {ital K}=215 MeV.
16308546
First Order Phase Transition in Intermediate-Energy Heavy Ion Collisions
We model the disassembly of an excited nuclear system formed as a result of a heavy ion collision. We find that, as the beam energy in central collisions in varied, the dissociating system crosses a liquid-gas coexistence curve, resulting in a first-order phase transition. Accessible experimental signatures are identified: a peak in specific heat, a power-law yield for composites, and a maximum in the second moment of the yield distribution.
119186084
Bimodality and Coulomb effects with a canonical thermodynamic model
Abstract The effect of the Coulomb interaction on the phase diagram of finite nuclei is studied within the Canonical Thermodynamic Model. If Coulomb effects are artificially switched off, this model shows a phenomenology consistent with the liquid–gas phase transition. The inclusion of Coulomb does not significantly affect the phase diagram but it drastically modifies the nature and order parameter of the transition. A clear understanding of the phenomenon can be achieved looking at the distribution of the largest fragment produced in each fragmentation event. Possible connections with experimental observations are outlined.
121836312
Excluded volume in nuclear fragmentation
14927510
A Transport Model for Nuclear Reactions Induced by Radioactive Beams
Major ingredients of an isospin and momentum dependent transport model for nuclear reactions induced by radioactive beams are outlined. Within the IBUU04 version of this model we study several experimental probes of the equation of state of neutron‐rich matter, especially the density dependence of the nuclear symmetry energy. Comparing with the recent experimental data from NSCL/MSU on isospin diffusion, we found a nuclear symmetry energy of Esym(ρ) ≈ 31.6(ρ/ρ0)1.05 at subnormal densities. Predictions on several observables sensitive to the density dependence of the symmetry energy at supranormal densities accessible at GSI and the planned Rare Isotope Accelerator (RIA) are also made.
118602353
Zero textures of the neutrino mass matrix from cyclic family symmetry
Abstract We present the symmetry realization of the phenomenologically viable Frampton–Glashow–Marfatia (FGM) two zero texture neutrino mass matrices in the flavor basis within the framework of the type ( I + II ) seesaw mechanism natural to SO(10) grand unification. A small Abelian cyclic symmetry group Z 3 is used to realize these textures except for class C for which the symmetry is enlarged to Z 4 . The scalar sector is restricted to the Standard Model (SM) Higgs doublet to suppress the flavor changing neutral currents. Other scalar fields used for symmetry realization are at the most two scalar triplets and, in some cases, a complex scalar singlet. Symmetry realization of one zero textures has, also, been presented.
119791096
Partial deconfinement of quarks in nuclei and the EMC effect
We investigate the possibility that in a heavy nucleus a few nucleons exist in a state of total deconfinement. The constituents of these deconfined nucleons are regarded as a mixture of quark-and gluon-gases in thermal equilibrium at a fixed temperatureT. This approach reproduces the observed softening of the valence quarks in heavy nuclei and predicts fewer gluons atx<1 and an exponential decrease of the structure functions atx>1.
120756008
Supercooling in viscous hydrodynamics for QCD phase transition
First order quark hadron phase transition is considered in scaling hydrodynamics including the Csernai-Kapusta model of nucleation of hadronic bubbles leading to supercooling. The effect of viscosity on the entropy production is studied in ideal as well as in viscous hydrodynamics with and without supercooling. It is found that the excess entropy produced due to supercooling depends weakly on viscosity.
11061527
{chi}{sub 1} and polarization asymmetries for quarkonia at high orders in nonrelativistic QCD
We study doubly polarized asymmetries of {bar c}c and {bar b}b mesons in hadroproduction and photoproduction at low transverse momentum in nonrelativistic QCD to high orders in the relative velocity of the pair, v. We give the complete set of expressions required for the asymmetries up to order v{sup 9}. The asymmetries in the production of {eta}{sub c,b} states are a stable measure of the polarized gluon densities. The asymmetries for {chi}{sub c,b}, J/{psi}, {psi}{sup {prime}}, and the various {Upsilon} states are stringent tests of the NRQCD scaling relations. {copyright} {ital 1997} {ital The American Physical Society}
124703371
FEL ACTIVITIES IN INDIA
We are building a Compact Ultrafast TErahertz FreeElectron Laser (CUTE-FEL), designed to lase from 50 – 100 μm. The FEL will be driven by a 10-15 MeV electron beam from a Plane-Wave Transformer (PWT) linac. The undulator is a 5 cm period, 2.5 m long PPM planar undulator. We present details of the FEL design and the present status of activities. We also present very preliminary plans for a short-wavelength SASE FEL in India.