arXiv subjects
Publications and source records attributed to D. K. Choudhury.
We modify the mesonic wavefunction by using a short distance scale r0 in analogy with Hydrogen atom and estimate the values of masses and decay constants of the open flavour charm mesons D, Ds and Bc within the framework of a QCD Potential Model. We also calculate leptonic decay widths of these mesons to study branching ratios and life time. The results are in good agreement with experimental and other theoretical values.
We use WKB Approximation in the calculation of slope and curvature of Isgur-Wise function in a QCD inspired potential model.This work is an extension of the approximation methods to the QCD inspired potential model.The approach hints at an effective range of distance for the calculation of slope and curvature of Isgur-Wise function.Comparision is also made with those of Dalgarno and VIPT to see the advantages of using WKB Approximation.
We use VIPT in calculating the elastic form factors and charge radii of D, Ds, B, Bs and Bc mesons in a QCD inspired potential model. For that we use linear cum Coulombic potential and opt firstly the Coulombic part as parent and then linear part as parent.The results show that charge radii and form factors are quite small for Coulombic parent case than the linear parent. Also, the analysis leads to a lower as well as upper bound on the four momentum transfer Q2 hinting at a workable range of Q2 within this approach which may be useful in future for experimental analysis. Comparision of both the options prefer the linear parent.
Unintegrated parton density functions (uPDFs) of Quantum Chromodynamics (QCD), also known as TMDPDFs, are generally used to study details of hadronic final states in high energy lepton-hadron and hadron-hadron collisions; while the integrated parton density functions (PDFs) are used for conventional deep inelastic inclusive processes. The self-similarity based Model of proton structure function $ F_{2}(x,Q^{2}) $ suggested in recent years are however based on specific uPDFs with self-similarity at small \textit{x}. In this work, we study large \textit{x} limit of such a Model and modify the defining uPDFs to make them compatible with theoretical expectations in such limit. Possibility of saturation of Froissart bound in this Model is discussed. We also reanalyze the PDFs in this approach using its conventional relation with TMDPDFs.
The QCD inspired potential model persued by us earlier has been recently modified to incorporate an additional factor 'c' in the linear cum Coulomb potential. While it felicitates the inclusion of standard confinement parameter b = 0.183GeV 2, unlike in previous work, it still falls short of explaining the Isgur-Wise function for the B mesons without adhoc adjustment of the strong coupling constant. In this work, we determine the factor 'c' from the experimental values of decay constants and masses and show that the reality constraint on 'c' yeilds bounds on the strong coupling constant as well on slope and curvature of Isgur-Wise function allowing more flexibility to the model.
In recent years, Fractal Inspired Models of quark and gluon densities at small x have been proposed. In this paper, we investigate longitudinal structure function F-L (x, Q2) within this approach. We make predictions using the QCD based approximate relation between the longitudinal structure function and the gluon density. As the Altarelli-Martinelli equation for the longitudinal structure function cannot be applied to Model I due to the presence of a singularity in the Bjorken x-space we consider Model II only. The qualitative feature of the prediction of Model II is found to be compatible with the QCD expectation.
Study of parton distribution function (PDF) is a topic of significant interest in QCD. To overcome the shortcomings of conventional PDFs, several alternative methods have been suggested in recent years. The present work reports the x distribution of the Non-singlet structure function in Leading order using the complete solution of Taylor-approximated DGLAP equation. The formalism is more general than the similar ones reported in recent literature. Our predictions are compared with the CCFR neutrino data as well as exact results.
In this paper we present solutions of the coupled DGLAP equations for quark and gluon singlet by applying the method of characteristics. Solutions are presented both in analytic and semi-analytic forms, compared with the exact results and the validity range obtained.
Polarised singlet DGLAP equations are solved by applying the method of characteristics. The singlet equations are first transformed into a pair of coupled partial differential equations by a Taylor series expansion valid to be at small x. The equations are then reduced to canonical forms and the resultant equations solved by applying the method of characteristics. Results are compared with some exact solutions of polarised DGLAP equations available in the literature.
Using the concept of self similarity in the structure of the proton at small $x$, we comment on possibility of a single positive fractal dimension of proton in analogy with classical monofractals. Plausible dynamics and physical interpretation of fractal dimension are also discussed.
Recently the concept of self similarity in the structure of the proton at small x has been introduced. We estimate the fractal dimension of proton in analogy with classical monofractals.
We obtain an approximate analytical form of the gluon distribution using the GLAP equation with a factorization ansatz,and test its validity by comparing it with that of Gluck,Reya and Vogt at low $x$ regime. We also present calculations of the longitudinal structure functions.