J. M. S. Rana | Searcharxiv

arXiv2007

Implications of η' Coupling in the Chiral Constituent Quark Model

Using the latest data pertaining to \bar u-\bar d asymmetry and the spin polarization functions, detailed implications of the possible values of the coupling strength of the singlet Goldstone boson η' have been investigated in the \chiCQM with configuration mixing. Using Δu, Δ_3, \bar u-\bar d and \bar u/\bar d, the possible ranges of the coupling parameters a, α^2 a, β^2 a and ζ^2 a, representing respectively the probabilities of fluctuations to pions, K, ηand η^{'}, are found. To further constrain the coupling strength of η', detailed fits have been obtained for spin polarization functions, quark distribution functions and baryon octet magnetic moments. The fits clearly establish that a small non-zero value of the coupling of η' is preferred over the higher values of $η'$ as well as when ζ=0, the latter implying the absence of η' from the dynamics of \chiCQM. Our best fit achieves an overall excellent fit to the data, in particular for Δu, Δd, Δ_8 as well as the magnetic moments μ_{n}, μ_{Σ^-}, μ_{Σ^+} and μ_{Ξ^-}. The implications of η' on the gluon polarization have also been investigated.

hep-ph↗

arXiv2006

Chiral constituent quark model and the coupling strength of eta'

Using the latest data pertaining to \bar u-\bar d asymmetry and the spin polarization functions, detailed implications of the possible values of the coupling strength of the singlet Goldstone boson η' have been investigated in the \chiCQM with configuration mixing. Using Δu, Δ_3, \bar u-\bar d and \bar u/\bar d, the possible ranges of the coupling parameters a, α^ 2, β^ 2 and ζ^ 2, representing respectively the probabilities of fluctuations to pions, K, ηand η^{'}, are shown to be 0.10 \lesssim a \lesssim 0.14, 0.2\lesssim α\lesssim 0.5, 0.2\lesssim β\lesssim 0.7 and 0.10 lesssim |ζ| \lesssim 0.70. To constrain the coupling strength of η', detailed fits have been obtained for spin polarization functions, quark distribution functions and baryon octet magnetic moments corresponding to the following sets of parameters: a=0.1, α=0.4, β=0.7, |ζ|=0.65 (Case I); a=0.1, α=0.4, β=0.6, |ζ|=0.70 (Case II); a=0.14, α=0.4, β=0.2, ζ=0 (Case III) and a=0.13, α=β=0.45, |ζ|=0.10 (Case IV). Case I represents the calculations where a is fixed to be 0.1, in accordance with earlier calculations, whereas other parameters are treated free and the Case IV represents our best fit. The fits clearly establish that a small non-zero value of the coupling of η' is preferred over the higher values of η' as well as when ζ=0, the latter implying the absence of η' from the dynamics of \chiCQM. Our best fit achieves an overall excellent fit to the data, in particular the fit for Δu, Δd, Δ_8 as well as the magnetic moments μ_{n}, μ_{Σ^-}, μ_{Σ^+} and μ_{Ξ^-} is almost perfect, the μ_{Ξ^-} being a difficult case for most of the similar calculations.

hep-ph↗

arXiv2004

Singlet GB contributions in the chiral constituent quark model

The implications of the latest data pertaining to \bar u-\bar d asymmetry and the spin polarization functions on the contributions of singlet Goldstone boson η' within \chiCQM with configuration mixing for explaining the ``proton spin problem'' have been investigated. It is found that the present data favors smaller values of the coupling of singlet Goldstone Boson η' as compared to the corresponding contributions from π, K and ηGoldstone bosons. It seems that a small non-zero value of the coupling of η' (ζ\neq 0) is preferred over ζ=0 phenomenologically.

hep-ph↗

arXiv1999

A condition for first order phase transitions in quantum mechanical tunneling models

A criterion is derived for the determination of parameter domains of first order phase transitions in quantum mechanical tunneling models. The criterion is tested by application to various models, in particular to some which have been used recently to explore spin tunneling in macroscopic particles. In each case agreement is found with previously heuristically determined domains.

cond-mat.mes-hall↗

arXiv1997

Simple Calculation of Quantum Spin Tunneling Effects

The level splitting formulae much discussed in the study of spin tunneling in macroscopic ferromagnetic particles and previously derived only by complicated pseudoparticle methods for the ground state, are derived from those of eigenvalues of periodic equations and extended to excited states.

cond-mat↗