Models and Potentials in Hadron Spectroscopy

In the past twenty years, hadron spectroscopy has made immense progress. Experimental facilities have observed different multiquark states during these years. There are different models and phenomenological potentials to study the nature of interquark interaction. In this work, we have reviewed different quark potentials and models used in hadron spectroscopy.Comment: 35 pages, 1 figur

Minimum Magnetizability Principle

A new electronic structure principle, viz. the minimum magnetizability principle (MMP) has been proposed and also has been verified through ab initio calculations, to extend the domain of applicability of the conceptual density functional theory (DFT) in explaining the magnetic interactions and magnetochemistry. This principle may be stated as, "A stable configuration/conformation of a molecule or a favorable chemical process is associated with a minimum value of the magnetizability". It has also been shown that a soft molecule is easily polarizable and magnetizable than a hard one.Comment: 2 Pages, 3 Figure

On the chromoelectric permittivity and Debye screening in hot QCD

We study the response functions (chromo-electric susceptibilities) for an interacting quark-gluon plasma. The interaction effects have been encoded in the effective fugacities for quasi-partons which are extracted self-consistently from the two equations of state for hot QCD. The first one is the fully perturbative $O(g^5)$ EOS and, the second one which is $O(g^6\ln(1/g))$, incorporates some non-perturbative effects. We find that response function shows large deviations from the ideal behavior. We further determine the temperature dependence of the Debye mass by fixing the effective coupling constant $Q^2$ which appears in the transport equation. We show that our formalism naturally yields the leading order HTL expression for the Debye mass if we employ the ideal EOS. Employing the Debye mass, we estimate the dissociation temperatures for various charmonium and bottomonium bound states. These results are consistent with the current theoretical studies.Comment: 9 pages, 8 figures, v2:minor typo corrected, improved version of arXiv:0801.1286[Section I-IV included and modified]; To appear in Euro. Physical J.

Regge Trajectories of Tetraquarks and Pentaquarks with Massive Quarks in the Flux Tube Model

In recent years, many tetraquarks and pentaquarks have been discovered by various experimental groups and X(3872), Zc(3900), X(4430), P + c (4312), P + c (4457) are some of the interesting observed tetraquark and pentaquark states. The Regge trajectories of some such states are studied in view of the flux tube model of hadrons with finite quark masses. The effect of flux tube (or string) length variation on the Regge trajectories of these sates is analysed in detail. It is observed that for a fixed angular momentum, the string length has a constant value. Some other states are also proposed and the results obtained are then compared with the studies by others. Our findings correspond rather well with those of other researchers and with those of the experiment.Comment: 10 pages, 4 figures, Published in IJMP

First Report of Magnificent Catshark, Proscyllium magnificum Last and Vongpanich, 2004 (Proscylliidae: Carcharhiniformes) from Bay of Bengal, Indian EEZ

Present paper reports the occurrence of magnificent catshark Proscyllium magnificum Last & Vongpanich, 2004 from Indian EEZ, off Andaman Islands in the Bay of Bengal. The two specimen P. magnificum (22.7-32.8 cm TL) caught by deep sea trawlers off South of Sentinel Island at depth of 300 m and landed at Junglighat fish landing centre, Port Blair formed material for the second report of P. magnificum after original description and first report from India