The real part of the polarization potential which depends on both energy and angular momentum is calculated in a simple way using dispersion relation. A barrier penetration model (BPM) has been used to explain the fusion cross-section and compound nucleus spin distribution for³²S+⁶⁴Ni system in the energy range 50–75 MeV. It is also shown that the polarization potential which only depends on energy, is not adequate to give rise to correct spin distribution even after including any radial dependence. The proposed polarization potential with implicitE andl dependences is able to explain both fusion cross-section and average spin values.

The energyE and angular momentuml dependence of optical potential for fusion of¹⁶O+²⁰⁸Pb system, observed by Christleyet al [5], is expressed as a function of radial kinetic energy (ɛ) instead of explicitE andl dependence. It is shown that the effects of different channel couplings, which result in different effective potentials, can also be parametrized as a function ofɛ. A correlation is obtained between the energy dependent part of this effective potential and the maximum of the spin enhancement around the Coulomb barrier and both these quantities depend on the details of the channel couplings.

Heavy ion fusion cross sections and compound nucleus average spin values obtained from distribution of fusion barriers are discussed. Various shapes of distribution functions are studied using a truncated Gaussian distribution function (TGD). It is shown that fusion cross section and average spin values are less sensitive to different parametrization of TGD function, whereas the second derivative of the product of energy and fusion cross sections (w.r.t. energy), obtained from the corresponding TGD functions are significantly different depending on the shape of the barrier distribution function. It is also shown byχ² analysis of fusion cross section data that some systems favour a narrow Gaussian distribution function whereas others, for which the vibrational and rotational collective states are less important, favour a flat barrier distribution. A physical interpretation of the dynamical process that gives rise to different barrier distribution is given in the framework of microscopic coupled channel calculations.

The method of optical model analysis of generalized elastic scattering angular distributions (GESA) has been applied to heavy ion scattering to derive fusion spin distributions. This method is used to reproduce the coupled channel fusion spin distributions. When applied to experimental data, particularly to the fissile systems like¹⁶O +²³²Th, the method gives large mean square spin values in agreement with “anomalous” values derived from experimental fission fragment anisotropies.

The PHENIX experiment consists of a large detector system located at the newly commissioned relativistic heavy ion collider (RHIC) at the Brookhaven National Laboratory. The primary goal of the PHENIX experiment is to look for signatures of the QCD prediction of a deconfined high-energy-density phase of nuclear matter quark gluon plasma. PHENIX started data taking for Au+Au collisions at √sNN=130 GeV in June 2000. The signals from the beam-beam counter (BBC) and zero degree calorimeter (ZDC) are used to determine the centrality of the collision. A Glauber model reproduces the ZDC spectrum reasonably well to determine the participants in a collision. Charged particle multiplicity distribution from the first PHENIX paper is compared with the other RHIC experiment and the CERN, SPS results. Transverse momentum of photons are measured in the electro-magnetic calorimeter (EMCal) and preliminary results are presented. Particle identification is made by a time of flight (TOF) detector and the results show clear separation of the charged hadrons from each other.

A scintillator-based hodoscope is fully operational at Nuclear Physics Division, Bhabha Atomic Research Centre (NPD-BARC). It was used for characterizing the resistive plate chambers (RPCs) assembled for the RE4 upgrade for the compact muon solenoid (CMS) experiment, installed during the long shut-down (LS1) using cosmic muons. It has now been employed for R & D related to gas mixtures and glass RPCs for the Indiabased neutrino observatory (INO) and muon tomography studies. The hodoscope is equipped with gas flow lines,LV, HV and VME-based DAQ with multihit TDCs. CERN-based software was adapted, implemented and along with the cosmic trigger, was used to evaluate the functional parameters for the RPCs, such as efficiency, clustersize etc.