118840350
Universality of the EMC effect
Using effective field theory, we investigate nuclear modification of nucleon parton distributions (for example, the EMC effect). We show that the universality of the shape distortion in nuclear parton distributions (the factorisation of the Bjorken x and atomic number (A) dependence) is model independent and emerges naturally in effective field theory. We then extend our analysis to study the analogous nuclear modifications in isospin and spin-dependent parton distributions and generalised parton distributions.
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.
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.
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.
118576689
{pi}{pi} scattering in twisted mass chiral perturbation theory
In this report we describe both I=2 and I=0 {pi}{pi} scattering for twisted mass lattice QCD utilizing twisted mass chiral perturbation theory at next-to-leading order. Focusing on the lattice spacing (b) corrections, we demonstrate that in the exotic I=2, I{sub 3}={+-}2 channels ({pi}{sup {+-}}{pi}{sup {+-}}), the leading scaling violations of {pi}{pi} scattering at maximal twist begin at O(m{sub {pi}}{sup 2}b{sup 2}). This is not the case in any other isospin channel, for which the scaling violations at maximal twist begin at O(b{sup 2}). Furthermore, we demonstrate the existence of a mixing between the I=2, I{sub 3}=0 and I=0 scattering channels due to the breaking of isospin symmetry by the twisted mass term. The mixing term, although formally next-to-leading order, is relatively large, thus necessitating the use of a coupled channel analysis. We argue that this mixing likely renders the computation of the I=0 channel impractical with twisted mass lattice QCD.
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.
18805981
System size and energy dependence of phi meson production at RHIC
We present a system size and energy dependence of meson production in Cu + Cu and Au + Au collisions at GeV and 200 GeV measured by the STAR experiment at RHIC. We find that the number of participant scaled meson yields in heavy-ion collisions over that of p + p collisions are larger than 1 and increase with collision energy. We compare the results with those of open-strange particles and discuss the physics implication.
121652117
The L-G Phase Transition and the Nucleon–Nucleon Interaction Potential within QHD-I Model
The nucleon–nucleon interaction potential in hot/dense nuclear matter is studied within the QHD-I model. We find that a Yukawa potential, which contains attractive and repulsive terms, acting between nucleons is modified by the variation of the Debye mass. In particular, a nucleon system described by this Yukawa potential will be unbound at some critical T and μ. The critical point is very close to that of the L-G phase transition given in the literatures.
119269362
LEPTON FLAVOR VIOLATION IN INVERSE SEESAW MODEL
We analyze the lepton flavor violation processes μ-e conversion, li→ljγ and li→3lj in framework of the Standard Model (SM) extended with inverse seesaw mechanism, as a function of that parametrizes the departure from unitary of the light neutrino mixing sub-matrix . In a wide range of , the predictions on the μ-e conversion rates and the branching ratio of μ→eγ are sizeable to be compatible with the experimental upper limits or future experimental sensitivities. For large scale of , the predictions on branching ratios of other lepton flavor processes can also reach the experimental upper limits or future experimental sensitivities. The value of depends on the determinant of the Majorana mass term Mμ. Finally, searching for lepton flavor violation processes in experiment provides us more opportunities for the searches of seesaw nature of the neutrino masses.
125746382
Heuristic approach to Unusual photon isospin mixing effects on the thermodynamics of compact nuclear matter
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.