Dilepton Production In Non-equilibriated Quark Gluon Plasma

A model of cut-off momentum distribution functions in a Quark Gluon Plasma with finite baryon chemical potential is discussed. This produces a quark gluon plasma signature in Ultra Relativistic Nuclear Collisions with a specific structure of the dilepton spectrum in the transverse momentum region of $(1-4)~GeV$ and the dilepton production rate is found to be a strong decreasing function of the chemical potential.Comment: Revtex 3 pages, 4 figures. To be submitted in Journal of Physics

The phase structure of QGP-Hadron in a statistical model using Cornell, Richardson and Peshier potentials

We study the phase structure of the QGP-Hadron system under quasi-static equilibrium using the Ramanathan et al. statistical model for the QGP fireball formation in a hadronic medium. While in the earlier published studies we had used the Peshier effective potential which is appropriate for the deconfined QGP phase but could be extrapolated to the transition region from the higher momentum regime, in this paper we study the same system using the Cornell and Richardson potentials which are more relevant for the low momentum confinement regime, but could again be extrapolated to the transition region from below. Surprisingly, the overall picture in both the cases are quite similar with minor divergences,(though,the results with the Richardson potential shows a sizable deviation from the other two potentials), thus indicating the robustness of the model and its self-consistency. The result of our numerical results pertaining to the variation of the velocity of sound in the QGP-Hadron medium with temperature in the various scenarios considered by us, is that, the phase transition seems to be a gentle roll-over of phases rather than a sharp transition of either the first or second order, a result in conformity with recent lattice calculations, but with much less effort.Comment: LaTex 5 pages and 6 figure

Role of BCS-type pairing in light deformed nuclei: A relativistic mean field approach

We calculate the binding energy and deformation parameter for light nuclei with and without pairing using a deformed relativistic mean field model. The role of BCS-type pairing effect is analyzed for Ne and F isotopes. The calculated odd-even staggering and the deformation parameters argue strongly against the role of pairing in the light nuclei.Comment: 7 pages, 4 figure

Thermal and interfacial properties of a Quark Gluon Plasma droplet in a hadronic medium via a statistical model

Thermal and interfacial properties of a QGP droplet in a hadronic medium are computed using a statistical model of the system. The results indicate a weakly first order transition at a transition temperature \sim (160 \pm 5) MeV. The interfacial surface tension is proportional to the cube of the transition temperaure irrespective of the magnitude of the transition temperature. The velocity of sound in the QGP droplet is predicted to be in the range (0.27 \pm 0.02) times the velocity of light in vacuum, and this value is seen to be independent of the value of the transition temperature as well as the model parameters. These predictions are in remarkable agreement with Lattice Simulation results and extant MIT Bag model predictions.Comment: LaTeX 21 pages, 11 figures, Some modifications in figures and reference

A model density of states for Quarks and Gluons in QGP

We propose an algebraic form for the density of states of quarks and gluons in a Quark-Gluon Plasma (QGP) fireball in quasi-equilibrium with a hadronic medium as $\rho(k)= \frac {\alpha}{k} + {\beta}k + {\delta}k^{2}$, and determine the parameters $\alpha$, $\beta$ and $\delta$ using Lattice Gauge results on the velocity of sound in QGP. The behaviour of the resulting $\rho(k)$ can be easily compared with the thermodynamic data on QGP that is expected from LHC and other RHIC experiments. Our numerical result shows a linear rise of the value of $\rho(k)$ for $k\sim T \approx 160 to 180 MeV$, which is significant, and throws light on the evolution of the QGP phase.Comment: 7 pages, 2 figures LaTe

The island of deformation and shape co-existence in neutron-deficient nuclei of the Pb region using relativistic mean field model

We have investigated the ground-state structures of even-even neutron-deficient isotopes of Hg and Pb nuclei within the framework of a deformed relativistic mean field formalism for a number of commonly used parameter sets, namely NL1, NL3, NL-SH, NL-RA1 and TM1. The ground states of a bunch of Hg and Pb-isotopes towards the proton-dripline are found to be deformed for all the forces, with a constant pairing gap. The small differences in the ground- and the first-excited state binding energies predict a sea of low-lying excited states, and hence of shape co-existence, for both the Hg and Pb nuclei. In general, a discrepancy between the experimentally observed and theoretically predicted (sign of) quadrupole deformations is noticed in this mass region. The constrained potential energy surfaces and the single-particle energy spectra analyzed for some selected nuclei show that the known large shell gap for Pb nuclei at Z=82 is almost extinguished for its proton-rich isotopes.Comment: Submitted for publicatio

Parameter Identification of Constrained Data by a New Class of Rational Fractal Function

This paper sets a theoretical foundation for the applications of the fractal interpolation functions (FIFs). We construct rational cubic spline FIFs (RCSFIFs) with quadratic denominator involving two shape parameters. The elements of the iterated function system (IFS) in each subinterval are identified befittingly so that the graph of the resulting $\mathcal{C}^1$-RCSFIF lies within a prescribed rectangle. These parameters include, in particular, conditions on the positivity of the $\mathcal{C}^1$-RCSFIF. The problem of visualization of constrained data is also addressed when the data is lying above a straight line, the proposed fractal curve is required to lie on the same side of the line. We illustrate our interpolation scheme with some numerical examplesComment: 16 pages, 9 Figures. Presented by Sangita Jha at International Conference on Mathematics and Computing, Haldia, January 17-21, 201

Gravitational wave from rotating neutron star

Using the nuclear equation of states for a large variety of relativistic and non-relativistic force parameters, we calculate the static and rotating masses and radii of neutron stars. From these equation of states, we also evaluate the properties of rotating neutron stars, such as rotational and gravitational frequencies, moment of inertia, quadrupole deformation parameter, rotational ellipcity and gravitational wave strain amplitude. The estimated gravitational wave strain amplitude of the star is found to be $\sim 10^{-23}$.Comment: 11 pages, 11 figures. arXiv admin note: text overlap with arXiv:nucl-th/0310075 by other author

Sources and characteristics of interior noise in general aviation aircraft

A field study was conducted to examine the interior noise characteristics of a general aviation aircraft. The goals were to identify the major noise sources and their relative contribution and to establish the noise transmission paths and their relative importance. Tests were performed on an aircraft operating under stationary conditions on the ground. Results show that the interior noise level of light aircraft is dominated by broadband, low frequencies (below 1,000 Hz). Both the propeller and the engine are dominant sources, however, the contribution from the propeller is significantly more than the engine at its fundamental blade passage frequency. The data suggest that the airborne path is more dominant than the structure-borne path in the transmission of broadband, low frequency noise which apparently results from the exhaust

A Comparative Study of Two Models of QGP-Fireball Formation

A Comparative study of the strengths and weakness of the models of fireball formation namely the statistical model of Ramanathan et.al (Physical Review C 70, 027903, 2004) and the approximation schemes of Kapusta et. al (Physical Review D 46, 1379, 1992) and its subsequent improved variants is made. The way to complement the various approximation schemes, in order to enhance their utility in the phenomenological analysis of QGP data that are expected from ongoing URHIC experiments, is suggested. The calculations demonstrate a striking QCD behaviour of the surface tension of the QGP droplet resulting in its increase with temperature, which is due to the confining nature of QCD forces at the surface and the interface surface tension varies as the cube of the transition temperature which is in conformity with the results of Lattice QCD simulations.Comment: Revtex 5 pages and 5 figures, Added some results and reference