International Journal of Modern Physics A

The rapidity density and transverse momentum distributions of produced particles in multiple particle production are formulated assuming that the produced particles are emitted isotropically from several emitting centers. The energy distribution of produced particles in the rest frames of respective emitting centers is that of the Tsallis statistics. The distribution of emitting centers is flat with slanting cuts at both shoulders on the rapidity axis in the center of mass system. The formulation includes six adjustable parameters, among which four are energy dependent and more important and are determined so that the transverse momentum and the (pseudo-)rapidity density distributions fit to the data at various energies. The energy dependences of the four parameters, determined empirically, reproduce quite well the energy dependence of the average transverse momentum, that of the pseudo-rapidity density at η* = 0 and that of the charged multiplicity. The energy dependence of the inelasticity is either increasing or decreasing from the assumed value of K = 0.5 at , due to lack of experimental data at the most-forward rapidity region. The pseudo-rapidity density distribution at LHC energy expected by the present formulation is compared with those by the other models.

In the present paper, we considered Galilean conformal algebras (GCAs), which arises as a contraction relativistic conformal algebras (x_i→ϵx_i, t→t, ϵ→0). We can use the Galilean conformal (GC) symmetry to constrain two-point and three-point functions. Correlation functions in space–time without boundary condition were found [A. Bagchi and I. Mandal, Phys. Lett. B675, 393 (2009).]. In real situations, there are boundary conditions in space–time, so we have calculated correlation functions for GC invariant fields in semi-infinite space with boundary condition in r = 0. We have calculated two-point and three-point functions with boundary condition in fixed time.

The measurement of the neutrino velocity with the OPERA detector in the CNGS beam shows unexpected indication, that the muon neutrino velocity, v_ν, exceeds the velocity of light in the vacuum, c, which is obviously in contradiction with the most basic hypothesis of modern physics. Within the framework of minimal Standard Model Extension (SME), we discuss the modified dispersion relation and consequently the velocity–energy relation of muon neutrinos. The simplified models are fitted to the OPERA data, Fermilab experiment and MINOS data. We find that minimal Standard Model Extension can describe these long baseline superluminal neutrinos to a good accuracy. For the well-known tension between the OPERA measurement and the Supernova 1987A neutrino observation, we discuss two ways out of the contradiction.

Using a holographic proposal for the geometric entropy we study its behavior in the geometry of Schwarzschild black holes in global AdS_p for p = 3, 4, 5. Holographically, the entropy is determined by a minimal surface. On the gravity side, due to the presence of a horizon on the background, generically there are two solutions to the surfaces determining the entanglement entropy. In the case of AdS₃, the calculation reproduces precisely the geometric entropy of an interval of length l in a two-dimensional conformal field theory with periodic boundary conditions. We demonstrate that in the cases of AdS₄ and AdS₅ the sign of the difference of the geometric entropies changes, signaling a transition. Euclideanization implies that various embedding of the holographic surface are possible. We study some of them and find that the transitions are ubiquitous. In particular, our analysis renders a very intricate phase space, showing, for some ranges of the temperature, up to three branches. We observe a remarkable universality in the type of results we obtain from AdS₄ and AdS₅.

We calculate the exclusive semileptonic and nonleptonic decays of B_c meson to heavy-light orbitally excited states in the framework of the improved Bethe–Salpeter method. The hadronic matrix elements are calculated and expressed as overlap integrals of the relativistic Salpeter wave functions of corresponding mesons, decay rates of the semileptonic and nonleptonic B_c decays to , and are obtained. Some channels provide us sizable ratios, for examples, and , with such ratios, the missing scalar B_s0 may be detected though its cascade strong decays in the forthcoming LHC experiment.

Landau gauge gluon propagators are studied numerically in the SU(3) gluodynamics as well as in the full QCD with the number of flavors n_F = 2 using efficient gauge fixing technique. We compare these propagators at temperatures very close to the transition point in two phases: confinement and deconfinement. The electric mass m_E has been determined from the momentum space longitudinal gluon propagator. Gribov copy effects are found to be rather strong in the gluodynamics, while in the full QCD case they are weak ("Gribov noise"). Also we analyze finite volume dependence of the transverse and longitudinal propagators.

In this work we study Lagrangian formulations for the noncommutative versions of the SU(2) Skyrme model and O(3) nonlinear sigma model. These formulations will be obtained using the Faddeev–Jackiw symplectic formalism. Other noncommutative Lagrangian formulations can be proposed and different noncommutative versions for these nonlinear systems can be obtained.

The purpose of this Comment is to point out that the results presented in the appendix of M. Mondragon and M. Montesinos, J. Math. Phys.47, 022301 (2006) provides a generic method so as to deal with cases as those of Sec. 6 of R. Cartas-Fuentevilla, A. Escalante-Hernández, and J. Berra-Montiel, Int. J. Mod. Phys. A26, 3013 (2011). The results already reported are: the canonical analysis, the transformations generated by the constraints, and the analysis of the reducibility of the constraints for SO(3, 1) and SO(4) four-dimensional BF theory coupled or not to a cosmological constant. But such results are generic and hold actually for any Lie algebra having a nondegenerate inner product invariant under the action of the gauge group.