118643259
Fate of non-Fermi-liquid behavior in QED 3 at finite chemical potential
The damping rate of two-dimensional massless Dirac fermions exhibit non-Fermi-liquid behavior, {proportional_to}{epsilon}{sup 1/2}, due to gauge field at zero temperature and zero chemical potential. We study the fate of this behavior at finite chemical potential. We first calculate explicitly the temporal and spatial components of vacuum polarization functions. The analytical expressions imply that the temporal component of gauge field develops a static screening length at finite chemical potential while the transverse component remains long-ranged owing to gauge invariance. We then calculate the fermion damping rate and show that the temporal gauge field leads to normal Fermi-liquid behavior but the transverse gauge field leads to non-Fermi-liquid behavior {proportional_to}{epsilon}{sup 2/3} at zero temperature. This energy dependence is more regular than {proportional_to}{epsilon}{sup 1/2} and does not change as chemical potential varies.
119270094
Confinement induced by fermion damping in three-dimensional QED
The three-dimensional noncompact QED is known to exhibit weak confinement when fermions acquire a finite mass via the mechanism of dynamical chiral symmetry breaking. In this paper, we study the effect of fermion damping caused by elastic scattering on the classical potential between fermions. By calculating the vacuum polarization function that incorporates the fermion damping effect, we show that the fermion damping can induce a weak confinement even when the fermions are massless and the chiral symmetry is not broken.
7189676
Radiative decay width measurements of neutral kaon excitations using the primakoff effect.
We use K(L)'s in the 100-200 GeV energy range to produce 147 candidate events of the axial vector pair K1(1270)-K1(1400) in the nuclear Coulomb field of a Pb target and determine the radiative widths Gamma(K1(1400)-->K0+gamma)=280.8+/-23.2(stat)+/-40.4(syst) keV and Gamma(K1(1270)-->K0+gamma)=73.2+/-6.1(stat)+/-28.3(syst) keV. These first measurements appear to be lower than the quark-model predictions. We also place upper limits on the radiative widths for K(*)(1410) and K(*)(2)(1430) and find that the latter is vanishingly small in accord with SU(3) invariance in the naive quark model.
119229425
Dirac Equation at Finite Temperature
In this paper, we propose finite temperature Dirac equation, which can describe the quantum systems in an arbitrary temperature for a relativistic particle of spin-1/2. When the temperature T=0, it become Dirac equation. With the equation, we can study the relativistic quantum systems in an arbitrary temperature.
55082285
GRB 071112C: A Case Study of Different Mechanisms in X-ray and Optical Temporal Evolution
We present a study on GRB 071112C X-ray and optical light curves. In these two wavelength ranges, we have found different temporal properties. The R-band light curve showed an initial rise followed by a single power-law decay, while the X-ray light curve was described by a single power-law decay plus a flare-like feature. Our analysis shows that the observed temporal evolution cannot be described by the external shock model in which the X-ray and optical emission are produced by the same emission mechanism. No significant color changes in multi-band light curves and a reasonable value of the initial Lorentz factor ({Gamma}{sub 0} = 275 {+-} 20) in a uniform interstellar medium support the afterglow onset scenario as the correct interpretation for the early R band rise. The result suggests that the optical flux is dominated by afterglow. Our further investigations show that the X-ray flux could be created by an additional feature related to energy injection and X-ray afterglow. Different theoretical interpretations indicate the additional feature in X-ray can be explained by either late internal dissipation or local inverse-Compton scattering in the external shock.
119188848
Excitonic Effects in Two-Dimensional Massless Dirac Fermions
We study excitonic effects in two-dimensional massless Dirac fermions with Coulomb interactions by solving the ladder approximation to the Bethe-Salpeter equation. It is found that the general four-leg vertex has a power-law behavior with the exponent going from real to complex as the coupling constant is increased. This change of behavior is manifested in the antisymmetric response, which displays power-law behavior at small wave vectors reminiscent of a critical state, and a change in this power law from real to complex that is accompanied by poles in the response function for finite-size systems, suggesting a phase transition for strong enough interactions. The density-density response is also calculated, for which no critical behavior is found. We demonstrate that exciton correlations enhance the cusp in the irreducible polarizability at $2{k}_{F}$, leading to a strong increase in the amplitude of Friedel oscillations around a charged impurity.
209048432
Search for supersymmetry in hadronic final states with missing transverse energy using the variables alphaT and b-quark multiplicity in pp collisions at sqrt(s) = 8 TeV