123275819
On the bounds of CKM matrix element Vcb in a potential model
Considering the allowed range of slope ρ2 and curvature C of Isgur–Wise function for B meson, we obtain an allowed range of strong coupling constant αs as well as the QCD scale parameter Λ in a specific prescription. The allowed range of Λ is then used to obtain the theoretical bounds on Vcb in a potential model. The recent available data of Vcb are found to lie within this computed range 0.0375 ≤|Vcb|≤0.0410.
126392027
Pinning down the self-similar gluon distribution from momentum sum rule
and explore the possibility of pinning down the gluon distribution G(x,Q) from it. The momentum sum rule is to be satisfied by any reasonable model of structure function. However, such requirement calls for information about the entire physical regime of x (0 6 x 6 1). It is also well-known that the gluon PDFs are, on the other hand, not directly measurable although there are several indirect ways of measuring like the longitudinal structure function or the slope and curvature of the structure function. We summarize the preliminary results of our analysis.
17488838
Comments on Fractality of Proton at Small x
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.
122709605
THE ISGUR–WISE FUNCTION IN AN IMPROVED QCD INSPIRED QUARK MODEL
We calculate the Isgur–Wise function of heavy light mesons and its derivatives — its slope and its curvature, in an improved version of our earlier QCD Inspired Quark Model with two-loop static potential.
120396984
Free-field theory, fixed-point theory, and electron-positron annihilation into hadrons
The R problem of electron-positron physics is analyzed within the frameworks of a free-field theory (parton models) and a field theory with an infrared-stable fixed point. Present data do not rule out either of these models and hence they both can survive as alternatives to standard QCD in the R problem.
123165880
A solution of the DGLAP equation for gluon at low x
We obtain a solution of the DGLAP equation for the gluon at low x first by expanding the gluon in a Taylor series and then using the method of characteristics. We test its validity by comparing it with that of Glück, Reya and Vogt. The convergence criteria of the approximation used are also discussed. We also calculate εF2(x,Q)2/ε In Q2 using its approximate relations with the gluon distribution at low x. The predictions are then compared with the HERA data.
119348603
Predictions for polarized-beam and/or vector-polarized-target observables in elastic Compton scattering on the deuteron
Motivated by ongoing developments at High-Intensity Gamma Source (HI\ensuremath{\gamma}S) at Triangle Universities Nuclear Laboratory (TUNL) that include increased photon flux and the ability to circularly polarize photons, we calculate several beam-polarization and/or target-spin-dependent observables for elastic Compton scattering on the deuteron. This is done at energies of the order of the pion mass within the framework of heavy-baryon chiral perturbation theory. Our calculation is complete to $\mathcal{O}({Q}^{3})$ and at this order there are no free parameters. Consequently, the results reported here are predictions of the theory. We discuss paths that may lead to the extraction of neutron polarizabilities. We find that the photon/beam polarization asymmetry is not a good observable for the purpose of extracting ${\ensuremath{\alpha}}_{n}$ and ${\ensuremath{\beta}}_{n}$. However, one of the double polarization asymmetries, ${\ensuremath{\Sigma}}_{x}$, shows appreciable sensitivity to ${\ensuremath{\gamma}}_{1n}$ and could be instrumental in pinning down the neutron spin polarizabilities.
9428112
Investigating neutron polarizabilities through Compton scattering on 3He.
We examine manifestations of neutron electromagnetic polarizabilities in coherent Compton scattering from the helium-3 nucleus. We calculate gamma3He elastic scattering observables using chiral perturbation theory to next-to-leading order [O(e2Q)]. We find that the unpolarized differential cross section can be used to measure neutron electric and magnetic polarizabilities, while two double-polarization observables are sensitive to different linear combinations of the four neutron spin polarizabilities.