Relations between some analytic representations of one-loop scalar integrals

We compare several parametrized analytic expressions for an arbitrary off-shell one-loop $n$-point function in scalar field theory in $D$-dimensional space-time, and show their equivalence both directly and through path-integral methods.Comment: 12 pages, NIKHEF-H/94-2

The Density of States Method at Finite Chemical Potential

We study the density of states method to explore the phase diagram of the chiral transition on the temperature and quark chemical potential plane. Four quark flavors are used in the analysis. Though the method is quite expensive small lattices show an indication for a triple-point connecting three different phases on the phase diagram.Comment: 5 pages, 6 figures, talk given at 'Extreme QCD', August 2-5 2005, Swansea, Wales, U

Azimuthal angle dependence of di-jet production in unpolarized hadron scattering

We study the azimuthal angular dependence of back-to-back di-jet production in unpolarized hadron scattering $H_A+H_B \to J_1 + J_2 +X$, arising from the product of two Boer-Mulders functions, which describe the transverse spin distribution of quarks inside an unpolarized hadron. We find that when the di-jet is of two identical quarks ($J_q+J_q$) or a quark-antiquark pair ($J_q+J_{\bar{q}}$), there is a $\cos \delta \phi$ angular dependence of the di-jet, with $\delta \phi=\phi_1-\phi_2$, and $\phi_1$ and $\phi_2$ are the azimuthal angles of the two individual jets. In the case of $J_q+J_q$ production, we find that there is a color factor enhancement in the gluonic cross-section, compared with the result from the standard generalized parton model. We estimate the $\cos \delta \phi$ asymmetry of di-jet production at RHIC, showing that the color factor enhancement in the angular dependent of $J_q+J_q$ production will reverse the sign of the asymmetry.Comment: 10 pages, 7 figures, version accepted by Physical Review

Generalized parton distributions from neutrino experiments

The analysis of deeply virtual meson production is extended to neutrino-production of the pseudo-Goldstone mesons (pions, kaons, eta-mesons) on nucleons, with the flavor content of the recoil baryon either preserved, or changed to a hyperon from the same SU(3) octet. We rely on the SU(3) relations and express all the cross-sections in terms of the proton generalized parton distributions (GPDs). The corresponding amplitudes are calculated at the leading twist level and in the leading order in \alpha_{s}, using a phenomenological parametrization of GPDs. We also included in the analysis the electromagnetic O(alpha_{em})-corrections to neutrino-induced deeply virtual meson production (\nuDVMP). We found that such electromagnetic corrections decrease with Q^2 in the Bjorken regime less than the standard \nuDVMP handbag contribution, so the electromagnetic mechanism dominates at large Q^2. The electromagnetic corrections give rise to an angular correlation between the lepton and hadron scattering planes with harmonics sensitive to the real and imaginary parts of the DVMP amplitude. These corrections constitute a few percent effect in the kinematics of the forthcoming MINERvA experiment at Fermilab and should be taken into account in precise tests of GPD parametrizations. For virtualities Q^2~100 GeV^2 these corrections become on a par with \nuDVMP handbag contributions.Comment: 5 pages, 3 figures, to appear in the proceedings of the DIS 2013 Workshop, Marseille, France, 22-26 April 201

Generalized parton distributions from neutrino experiments: twist-three effects

We study the twist-3 corrections to the neutrino induced deeply virtual meson production due to the chiral odd transversity Generalized Parton Distribution (GPD). We found that in contrast to pion electroproduction, in neutrino-induced processes these corrections are small. This occurs due to large contribution of unpolarized GPDs $H,\, E$ to the twist-2 amplitude in neutrinoproduction. Our results are important for analyses of the pion and kaon production in the Minerva experiment at FERMILAB.Comment: 4 pages, 1 figure. Contribution to the proceedings of the 13th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2013), Sep 30-Oct 4, Rome, Italy. Details of evaluation may be found in arXiv:1401.154