119457104
Is the Sullivan process compatible with QCD chiral dynamics
Abstract We calculate the leading non-analytic quark-mass dependence in the moments of isovector quark distributions using heavy-baryon chiral perturbation theory. The results differ from what has been obtained from the Sullivan process in which hard scattering occurs through the virtual pion cloud of the nucleon. Our results provide useful guidance in formulating meson-cloud models consistent with chiral dynamics and can be used to constrain the extrapolations of the existing lattice QCD results to the physical quark masses
13534760
Constructing parton convolution in effective field theory.
Parton convolution models have been used extensively in describing the sea quarks in the nucleon and explaining quark distributions in nuclei (the EMC effect). From the effective field theory point of view, we construct the parton convolution formalism which has been the underlying conception of all convolution models. We explain the significance of scheme and scale dependence of the auxiliary quantities such as the pion distributions in a nucleon. As an application, we calculate the complete leading nonanalytic chiral contribution to the isovector component of the nucleon sea.
119272530
Model analysis of thermal UV-cutoff effects on the chiral critical surface at finite temperature and chemical potential
We study the effects of temporal UV-cutoff on the chiral critical surface in hot and dense QCD using a chiral effective model. Recent lattice QCD simulations indicate that the curvature of the critical surface might change toward the direction in which the first-order phase transition becomes stronger on increasing the number of lattice sites. To investigate this effect on the critical surface in an effective model approach, we use the Nambu-Jona-Lasinio model with finite Matsubara frequency summation. We find that the nature of the curvature of the critical surface does not alter appreciably as we decrease the summation number, which is unlike the case that was observed in recent lattice QCD studies. This may suggest that the dependence of chemical potential on the coupling strength or some additional interacting terms such as vector interactions could play an important role at finite density.
119519405
Parity Violation in Polarized-Gamma Proton Compton Scattering
Polarized beam gamma p Compton scattering provides a theoretically clean way to extract the isovector parity violating pion-nucleon coupling constant $h_{\pi NN}^{(1)}$. This channel is more tractable experimentally than the recently proposed extraction of $h_{\pi NN}^{(1)}$ from the Bedaque-Savage process --- polarized target gamma p compton scattering. The leading parity violating effect is calculated using Heavy Baryon Chiral Perturbation Theory. The size of the asymmetry is estimated to be ~ 4 10^{-8} for 120 MeV photon energy.
119418730
Large-Nc quark distributions in the delta and chiral logarithms in quark distributions of the nucleon
Abstract In a world with two quark flavors and a large number of colors ( N c ), the polarized and unpolarized quark distributions in the delta are completely determined by those in the nucleon up to relative O (1/N c 2 ) . In particular, we find q Δ (x)=[(1±2T z )u N (x)+(1∓2T z )d N (x)]/2(1+ O (1/N c 2 )) and Δq Δ (x)=[(5±2T z )Δu N (x)+(5∓2T z )Δd N (x)]/10(1+ O (1/N c 2 )) , where q = u , d and T z the charge state of a delta. The result can be used to estimate the leading chiral-logarithmic corrections to the quark distributions in the nucleon.
119491739
Twisted valence quarks and hadron interactions on the lattice
Abstract We consider QCD with valence and sea quarks obeying different boundary conditions. We point out that the energy of low lying two hadron states do not depend on the boundary condition of the sea quarks (up to exponentially small corrections). Thus, the advantages in using twisted boundary conditions on the lattice QCD extraction of nucleon–nucleon phase shifts can be gained without the need of new gauge configurations, even in fully unquenched calculations.
122544309
THE MULTI-VALUE OF EFFECTIVE NUCLEON MASS IN HOT/DENSE NUCLEAR MATTER AND THE PHASE TRANSITION
From the Lagrangian of QHD-I model, we investigate the effective nucleon mass under the mean field approximation in a wide temperature region. The multi-solution of self-consistent equation for the effective mass in found. In the high temperature region, the relation between the multi-solutions and the phase transition is analyzed. Furthermore, the variation of energy density in this region is studied.
118966106
Relaxation from color Compton Scattering of Plasmons in A Collisionless Quark-Gluon Plasma
Non-Abelian kinetic effects are taken into account for the study of the relaxation of collective motion in a quark-gluon plasma(QGP). An explicit Compton scattering is considered to calculate the relaxation time. It is shown that the new non-Abelian relaxation has a physical mechanism from the non-linear dynamics and the meaning of the relaxation is discussed.
120493940
HEAVY STABLE CHARGED PARTICLE SEARCHES AT THE LHC
Several searches for heavy stable charged particles have recently been performed using data from $\sqrt{s} = 7 {\rm TeV}$pp collisions at the Large Hadron Collider (LHC). This review summarizes some of the theoretical and experimental motivations for such searches, and discusses searches for stable squarks, stable gluino, stable sleptons and multiply charged heavy stable particles with the CMS and ATLAS detectors.
123049469
Directed flow measurements from STAR
STAR measurements of v1 for identified particles for Au+Au collisions at = 200 GeV are presented. A negative v1 slope is observed for pions, protons, antiprotons and kaons (K0S) in 10-70% central collisions. For pion v1 slope, the comparison between the current result and available models (RQMD, UrQMD, AMPT, QGSM and hydro model with a tilted source) is made. In 5-30% central collisions, surprisingly sizable difference between v1 of protons and antiprotons is observed. The centrality and energy dependence of proton v1 are also presented. The charged hadron v1 for Cu+Cu collisions at = 22.4 GeV is measured and compared with results obtained previously.
125746382
Heuristic approach to Unusual photon isospin mixing effects on the thermodynamics of compact nuclear matter