Expectation of forward-backward rapidity correlations in p+pp+p collisions at the LHC energies

Forward-backward correlation strength ($b$) as a function of pesudorapidity intervals for experimental data from $p+\bar{p}$ non-singly diffractive collisions are compared to PYTHIA and PHOJET model calculations. The correlations are discussed as a function of rapidity window ($\Delta \eta$) symmetric about the central rapidity as well as rapidity window separated by a gap ($\eta_{gap}$) between forward and backward regions. While the correlations are observed to be independent of $\Delta \eta$, it is found to decrease with increase in $\eta_{gap}$. This reflects the role of short range correlations and justifies the use of $\eta_{gap}$ to obtain the accurate information about the physics of interest, the long range correlations. The experimental $b$ value shows a linear dependence on $\ln \sqrt{s}$ with the maximum value of unity being reached at $\sqrt{s}$ = 16 TeV, beyond the top LHC energy. However calculations from the PYTHIA and PHOJET models indicate a deviation from linear dependence on $\ln \sqrt{s}$ and saturation in the $b$ values being reached beyond $\sqrt{s}$ = 1.8 TeV. Such a saturation in correlation values could have interesting physical interpretations related to clan structures in particle production. Strong forward-backward correlations are associated with cluster production in the collisions. The average number of charged particles to which the clusters fragments, called the cluster size, are found to also increase linearly with $\ln \sqrt{s}$ for both data and the models studied. The rate of increase in cluster size vs. $\ln \sqrt{s}$ from models studied are larger compared to those from the data and higher for PHOJET compared to PYTHIA. Our study indicates that the forward-backward measurements will provide a clear distinguishing observable for the models studied at LHC energies.Comment: 15 pages, 14 Figures, accepted for publication in International Journal of Modern Physics

March Towards Green Steel Production-Efforts at Tata Steel

The paper discusses the various initiatives taken by Tata Steel in the utilisation of waste materials generated in the blast furnaces, LD plants and rolling mills. In its drive towards total utilisation of wastes, the company is likely to become the first integrated green steel industry in our country

Optimum Placement of Post-1PN GW Chirp Templates Made Simple at any Match Level via Tanaka-Tagoshi Coordinates

A simple recipe is given for constructing a maximally sparse regular lattice of spin-free post-1PN gravitational wave chirp templates subject to a given minimal match constraint, using Tanaka-Tagoshi coordinates.Comment: submitted to Phys. Rev.

Lepton interferometry in relativistic heavy ion collisions - a case study

We propose intensity interferometry with identical lepton pairs as an efficient tool for the estimation of the source size of the expanding hot zone produced in relativistic heavy ion collisions. This can act as a complementary method to two photon interferometry. The correlation function of two electrons with the same helicity has been evaluated for RHIC energies. The thermal shift of the rho meson mass has negligible effects on the HBT radii.Comment: 5 pages and 2 figure

Data analysis of gravitational-wave signals from spinning neutron stars. IV. An all-sky search

We develop a set of data analysis tools for a realistic all-sky search for continuous gravitational-wave signals. The methods that we present apply to data from both the resonant bar detectors that are currently in operation and the laser interferometric detectors that are in the final stages of construction and commissioning. We show that with our techniques we shall be able to perform an all-sky 2-day long coherent search of the narrow-band data from the resonant bar EXPLORER with no loss of signals with the dimensionless amplitude greater than $2.8\times10^{-23}$.Comment: REVTeX, 26 pages, 1 figure, submitted to Phys. Rev.

Constraints on non-minimally coupled curved space electrodynamics from astrophysical observations

We study interactions of electro-magnetic fields with the curvature tensor of the form $\lambda R_{\mu \nu \alpha \beta}F^{\mu \nu}F^{\alpha \beta}$. Such coupling terms though are invariant under general coordinate transformation and CPT, however violate the Einstein equivalence principle. These couplings do not cause any energy dependent dispersion of photons but they exhibit birefringence. We put constraints on the coupling constant $\lambda$ using results from solar system radar ranging experiments and millisecond-pulsar observations. We find that the most stringent constraint comes from pulsar observations and is given by $\lambda < 10^{11} cm^2$ obtained from the timing of binary pulsar PSR B1534+12.Comment: 9 pages latex, accepted in CQ

Matching of the continuous gravitational wave in an all sky search

We investigate the matching of continuous gravitational wave (CGW) signals in an all sky search with reference to Earth based laser interferometric detectors. We consider the source location as the parameters of the signal manifold and templates corresponding to different source locations. It has been found that the matching of signals from locations in the sky that differ in their co-latitude and longitude by $\pi$ radians decreases with source frequency. We have also made an analysis with the other parameters affecting the symmetries. We observe that it may not be relevant to take care of the symmetries in the sky locations for the search of CGW from the output of LIGO-I, GEO600 and TAMA detectors.Comment: 16 pages, 7 figures, 3 Tables, To appear in Int. J. Mod. Phys.

Quark-hadron phase transition with surface fluctuation

The effect of surface fluctuation on the observables of quark-hadron phase transition is studied. The Ginzburg-Landau formalism is extended by the inclusion of an extra term in the free energy that depends on the vertical displacements from a flat surface. The probability that a bin has a particular net displacement is determined by lattice simulation, where the physics input is color confinement. The surface fluctuation from bin to bin is related to multiplicity fluctuation, which in turn is measured by the factorial moments. It is found that both the F-scaling behavior and the scaling exponent are essentially unaffected by the inclusion of surface fluctuation.Comment: 9 pages, LaTex, 7 figures in a single postscript file, submitted to Phys. Rev.