Related papers: An attempt to understand exclusive pi+ electroprod…
The study of deeply virtual Compton scattering has shown that electromagnetic gauge invariance requires, to leading order, not only twist two but additional twist three contributions. We apply this analysis and, using the…
Single transverse spin asymmetry for the pion production in pp and ep collisions is studied in the framework of collinear factorization. The soft-gluon pole contributions with twist-3 distribution and fragmentation functions are identified…
We analyze the $\gamma N\to\pi N$ process in the negative parity channel with Hamiltonian effective filed theory which is successful in studying the nucleon resonances associated with the meson-nucleon scattering and lattice QCD…
We consider pion electroproduction close to threshold for $Q^2$ in the region 1-10 GeV$^2$ on a nucleon target. The momentum transfer dependence of the S-wave multipoles at threshold, $E_{0+}$ and $L_{0+}$, is calculated in the chiral limit…
Non-leading contribution to the pion electromagnetic form factor which comes from the pion twist-3 wave function is analyzed in the modified hard scattering approach (MHSA) proposed by Li and Sterman. This contribution is enhanced…
The amplitude for hard exclusive pseudoscalar meson electroproduction off nucleon (nuclear) targets is computed in QCD within the leading $\alpha_s \ln {Q^2/\lambda_{QCD}^{2}}$ approximation. We show that the distribution of recoil nucleons…
A fit to the existing pion electroproduction data is presented. This work builds upon our previous analyses of pion photoproduction and elastic pion-nucleon scattering over the Delta resonance region. We comment on the extraction of E_1+…
We study the beam spin asymmetry $A_{LU}^{\sin\phi_h}$ in semi-inclusive $\pi^0$ electroproduction contributed by the T-odd twist-3 distribution function $g^\perp(x,k_T^2)$. We calculate this transverse momentum dependent distribution…
Considering, as a limit case, an approximately flat pion distribution amplitude, which is determined from the hardest, in momentum space, solution of the Bethe-Salpeter equation for the pion wave function, we compute the pion transition…
Exclusive processes in hard electroproduction is one of the best place for understanding the factorization properties of QCD. The HERA experiment recently provided precise data for rho electroproduction, including all spin density matrix…
We consider pion electroproduction on a proton target close to threshold for Q^2 in the region 1-10 GeV^2. The momentum transfer dependence of the S-wave multipoles at threshold, E_{0+} and L_{0+}, is calculated using light-cone sum rules.
We apply a previously developed scheme to consistently include the twist-3 distribution amplitudes for transversely polarized rho meson in order to evaluate, in the framework of kT factorization, the helicity amplitudes for exclusive…
Exclusive photoproduction of heavy $J/\psi$ meson is performed within handbag factorization method. The General Parton Distributions (GPDs) for gluons which are an essential ingredient here, are constructed using double distribution (DD)…
Light meson electroproduction is analyzed on the basis of the handbag approach. Our results on the cross section and spin effects are in good agrement with experiments at HERA, COMPASS and HERMES energies. Predictions for $A_{UT}$ asymmetry…
We explore quark-hadron duality in semi-inclusive pion electroproduction on proton and neutron targets. Using the spin-flavor symmetric quark model, we compute ratios of pi+ and pi- cross sections for both unpolarized and polarized…
We evaluate perturbative next-to-leading order corrections to the hard exclusive leptoproduction of pi+ mesons on a transversely polarized proton target. A model dependent study shows that these corrections can be large. We analyze the…
Exclusive electroproduction of pi+ mesons was studied by scattering 27.6 GeV positrons or electrons off a transversely polarized hydrogen target. The single-spin azimuthal asymmetry with respect to target polarization was measured as a…
A single-spin asymmetry was measured in the azimuthal distribution of pi+pi- pairs produced in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target. For the first time, evidence is found for a correlation…
Exclusive electroproduction of $\pi^+\pi^-$ pairs off hydrogen and deuterium targets has been studied with the HERMES experiment. The angular distribution of the $\pi^+$ in the $\pi^+\pi^-$ rest system has been studied in the invariant mass…
Exclusive $\pi^o$ electroproduction and related processes are suggested to investigate the chiral odd transversity distributions of quarks in the transversely polarized nucleon, $h_1(x)$, and its first moment, the tensor charge. The…