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.
8108447
Analysis of a quark model with charm and color for inclusive processes.
The qqq-bar model of Mitra for meson-baryon processes is reformulated to study inclusive processes incorporating charm and color degrees of freedom. Predictions are made in terms of sum rules for various inclusive cross sections. Agreement of the sum rules with data is good for dsigma/dp/sub perpendicular/ /sup 2/ and dsigma/dx in the available range of p/sub perpendicular/ /sup 2//x. However, overall analysis of the flavor-symmetry breaking indicates that symmetries alone are not adequate and the underlying theory should contain a suitable mechanism to generate Regge-type behavior in the inclusive distributions. We also incorporate proton-wave-function modification due to gluons in our model.
119213656
Comparison of analytical solution of spin-dependent DGLAP equations for g_1^{NS}(x, t) at small x by two methods
Analytical solutions for the non-singlet polarized parton distribution are obtained by solving the DGLAP equation by two analytical methods: Lagranges Method and Method of Characteristics.The relative merits of the two methods are discussed while comparing with HERMES data in the small x region.We also calculate the partial spin fractions carried by small x, nonsinglet partons.
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.
119264904
The Oscillation Frequency of B and bar B Mesons in a QCD Potential Model with Relativistic Effects
Wavefunction at the origin, with the incorporation of a relativistic effect, leads to singularity in a specific potential model. To regularize the wavefunction, we introduced a short distance scale and used it to estimate the mass and decay constants of Bd and Bs mesons within the QCD potential model. These values were then used to compute the oscillation frequency, ΔmB, of Bd and Bs mesons. The values were found to be in good agreement with experimental and other theoretical values.
52508745
Semileptonic Decay of B c Meson into S Wave Charmonium in a QCD Potential Model with Coulombic Part as Perturbation
We present the semileptonic decay of Bc meson in a QCD potential model with the coulombic part of the Cornell potential -4αs/3r+br+c as perturbation. Computing the slope and curvature of Isgur Wise function in this approach, we study the pseudoscalar and vector form factors for the transition of Bc meson to its S wave charmonium states. Numerical estimates of widths for the transitions of Bc→J|ψ(ηc)lv1 are presented.
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.
119329980
Compton Scattering on He-3
We present first calculations for Compton scattering on $^3$He. The objective of the calculation is an extraction of the neutron polarizabilities.