Precision calculation for nucleon capture by deuteron with Effective Field Theory

We calculate the cross section for radiative capture of neutron by deuteron $n+d \to 3H+\gamma$ using Effective Field Theory(EFT). The calculation includes N2LO order and we compare our results with available calculated data below E=0.2 Mev.Comment: 4 pages, 1 eps figures, oral contribution, 19th European Few-Body Conference (fb19), Groningen, Netherlands, August 23 - August 27, 2004. To be published in the proceeding

Jet Quenching Parameter with Hyperscaling Violation

In this paper we study the behavior of jet quenching parameter in the background metric with hyperscaling violation at finite temperature.The background metric is covariant under a generalized Lifshitz scaling symmetry with the dynamical exponent z and hyperscaling exponent $\theta$. We evaluate the jet quenching parameter for certain range of these parameters consistent with the Gubser bound conditions in terms of T, z and $\theta$. We compare our results with those from conformal case and experimental data. Then we add a constant electric field to this background and find its effect on the jet quenching parameter.Comment: 22 pages, 9 figure

Neutron-Deuteron System and Photon Polarization Parameter at Thermal Neutron Energies

Effective Field Theory(EFT) is, the unique, model independent and systematic low-energy version of QCD for processes involving momenta below the pion mass. A low-energy photo-nuclear observable in three-body systems, photon polarization parameter at thermal neutron energies is calculated by using pionless EFT up to next-to-next to leading order(N$^2$LO). In order to make a comparative study of this model, we compared our results for photon polarization parameter with the realistic Argonne $v_{18}$ two-nucleon and Urbana IX or Tucson-Melbourne three-nucleon interactions. Three-body currents give small but significant contributions to some of the observables in the neutron-deuteron radiative capture cross section at thermal neutron energies. In this formalism the three-nucleon forces are needed up to N$^2$LO for cut-off independent results. Our result converges order by order in low energy expansion and also cut-off independent at this order.Comment: 10 pages, 3 figures, 2 table