35,236 research outputs found
Relations between some analytic representations of one-loop scalar integrals
We compare several parametrized analytic expressions for an arbitrary
off-shell one-loop -point function in scalar field theory in -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 , 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 () or a quark-antiquark pair
(), there is a angular dependence of the
di-jet, with , and and are the
azimuthal angles of the two individual jets. In the case of
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 asymmetry of di-jet production at
RHIC, showing that the color factor enhancement in the angular dependent of
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 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
- …