Abstract: In this paper, we study the existence of strange star in the background of modified gravity where is a scalar torsion. In KB metric space, we derive the equations of motion using anisotropic property within the spherically strange star with modified Chaplygin gas in the framework of modified gravity. Then we obtain many physical quantities to describe the physical status such as anisotropic behavior, energy conditions, and stability. By the matching condition, we calculate the unknown parameters to evaluate the numerical values of mass, surface redshift, etc., from our model to make comparison with the observational data. PubDate: Mon, 15 Oct 2018 07:07:42 +000

Abstract: We investigate the ghost model of dark energy in the framework of DGP braneworld. We explore the cosmological consequences of this model by determining the equation of state parameter, , the deceleration, and the density parameters. We also examine the stability of this model by studying the squared of the sound speed in the presence/absence of interaction term between dark energy and dark matter. We find out that in the absence of interaction between two dark sectors of the universe we have in the late time, while in the presence of interaction can cross the phantom line . In both cases the squared of sound speed does not show any signal of stability. We also determine the statefinder diagnosis of this model as well as the plane and compare the results with the CDM model. We find that plane meets the freezing region in the absence of interaction between two dark sectors, while it meets both the thawing and the freezing regions in the interacting case. PubDate: Sun, 14 Oct 2018 07:03:46 +000

Abstract: The transverse momentum spectra of ,,,,, and produced in Au+Au collisions at center-of-mass energy , 11.5, 19.6, 27, 39, 62.4, 130, and 200 GeV are analyzed in the framework of a multisource thermal model. The experimental data measured at midrapidity by the STAR Collaboration are fitted by the (two-component) standard distribution. The effective temperature of emission source increases obviously with the increase of the particle mass and the collision energy. At different collision energies, the chemical potentials of up, down, and strange quarks are obtained from the antiparticle to particle yield ratios in given transverse momentum ranges available in experiments. With the increase of logarithmic collision energy, the chemical potentials of light flavor quarks decrease exponentially. PubDate: Thu, 11 Oct 2018 06:42:50 +000

Abstract: We derive the complete set of off-shell nilpotent and absolutely anticommuting (anti-)BRST as well as (anti-)co-BRST symmetry transformations for the gauge-invariant Christ–Lee model by exploiting the celebrated (dual-)horizontality conditions together with the gauge-invariant and (anti-)co-BRST invariant restrictions within the framework of geometrical “augmented” supervariable approach to BRST formalism. We show the (anti-)BRST and (anti-)co-BRST invariances of the Lagrangian in the context of supervariable approach. We also provide the geometrical origin and capture the key properties associated with the (anti-)BRST and (anti-)co-BRST symmetry transformations (and corresponding conserved charges) in terms of the supervariables and Grassmannian translational generators. PubDate: Thu, 11 Oct 2018 00:00:00 +000

Abstract: The black hole information paradox and the black hole entropy are currently extensively researched. The consensus about the solution of the information paradox is not yet reached, and it is not yet clear what can we learn about quantum gravity from these and the related research. It seems that the apparently irreducible paradoxes force us to give up on at least one well-established principle or another. Since we are talking about a choice between the principle of equivalence from general relativity and some essential principles from quantum theory, both being the most reliable theories we have, it is recommended to proceed with caution and search more conservative solutions. These paradoxes are revisited here, as well as the black hole complementarity and the firewall proposals, with an emphasis on the less obvious assumptions. Some arguments from the literature are reviewed, and new counterarguments are presented. Some less considered less radical possibilities are discussed, and a conservative solution, which is more consistent with both the principle of equivalence from general relativity and the unitarity from quantum theory, is discussed. PubDate: Wed, 10 Oct 2018 00:00:00 +000

Abstract: Large liquid xenon detectors aiming for dark matter direct detection will soon become viable tools also for investigating neutrino physics. Information on the effects of nuclear structure in neutrino-nucleus scattering can be important in distinguishing neutrino backgrounds in such detectors. We perform calculations for differential and total cross sections of neutral-current neutrino scattering off the most abundant xenon isotopes. The nuclear-structure calculations are made in the nuclear shell model for elastic scattering and also in the quasiparticle random-phase approximation (QRPA) and microscopic quasiparticle-phonon model (MQPM) for both elastic and inelastic scattering. Using suitable neutrino energy distributions, we compute estimates of total averaged cross sections for B solar neutrinos and supernova neutrinos. PubDate: Thu, 04 Oct 2018 00:00:00 +000

Abstract: We examine the thermodynamic features of an exotic fluid known as modified cosmic Chaplygin gas in the context of homogeneous isotropic universe model. For this purpose, the behavior of physical parameters is discussed that help to analyze nature of the universe. Using specific heat formalism, the validity of third law of thermodynamics is checked. Furthermore, with the help of thermodynamic entities, the thermal equation of state is also discussed. The thermodynamic stability is explored by means of adiabatic, specific heat and isothermal conditions from classical thermodynamics. It is concluded that the considered fluid configuration is thermodynamically stable and expands adiabatically for an appropriate choice of parameters. PubDate: Wed, 03 Oct 2018 07:09:38 +000

Abstract: We solve the quantum system with the symmetric Razavy cosine type potential and find that its exact solutions are given by the confluent Heun function. The eigenvalues are calculated numerically. The properties of the wave functions, which depend on the potential parameter , are illustrated for a given potential parameter . It is shown that the wave functions are shrunk to the origin when the potential parameter increases. We note that the energy levels () decrease with the increasing potential parameter but the energy levels () first increase and then decrease with the increasing . PubDate: Tue, 02 Oct 2018 07:08:29 +000

Abstract: Photoproduction of mesons from nucleons can provide valuable information about the excitation spectrum of the nucleons. The angular dependence of photoproduction in the photon-induced reaction is investigated in the multisource thermal model. The results are compared with experimental data from the decay mode. They are in good agreement with the experimental data. It is shown that the movement factor increases linearly with the photon beam energies. And the deformation and translation of emission sources are visually given in the formalism. PubDate: Sun, 30 Sep 2018 09:06:19 +000

Abstract: The significant divergence between the SM predictions and experimental measurements for the ratios, with , implies possible hint of new physics in the flavor sector. In this paper, motivated by the “ puzzle” and abundant data samples at high-luminosity heavy-flavor experiments in the future, we try to probe possible effects of new physics in the semileptonic decays induced by transitions in the model-independent vector and scalar scenarios. Using the spaces of NP parameters obtained by fitting to the data of and , the NP effects on the observables including branching fraction, ratio , lepton spin asymmetry, and lepton forward-backward asymmetry are studied in detail. We find that the vector type couplings have large effects on the branching fraction and ratio . Meanwhile, the scalar type couplings provide significant contributions to all of the observables. The future measurements of these observables in the decays at the LHCb and Belle-II could provide a way to crosscheck the various NP solutions to the “ puzzle”. PubDate: Thu, 27 Sep 2018 00:00:00 +000

Abstract: In this study, the coupling constants of and vertices were determined within the three-point Quantum chromodynamics sum rules method with and without consideration of the symmetry. The coupling constants were calculated for off-shell charm and cases. Considering the nonperturbative effect of the correlation function, as the most important contribution, the quark-quark, quark-gluon, and gluon-gluon condensate corrections were estimated and were compared with other predictive methods. PubDate: Wed, 26 Sep 2018 00:00:00 +000

Abstract: We visited mass spectra and decay constants of pseudoscalar and vector heavy-light mesons (,,, and ) in the framework of QCD sum rule and quark model. The harmonic oscillator wave function was used in quark model while a simple interpolating current was used in QCD sum rule calculation. We obtained good results in accordance with the available experimental data and theoretical studies. PubDate: Tue, 25 Sep 2018 00:00:00 +000

Abstract: Brian Kong and the present author recently presented a new area spectrum and showed that the new area spectrum implies that the decay time of a single-partition black hole (i.e., a black hole with the area not big enough to have two or more partitions) is roughly constant. In this article, we show why the decay time of a single-partition black hole is roughly constant. PubDate: Mon, 24 Sep 2018 07:25:21 +000

Abstract: We study a spherically symmetric setup consisting of a Schwarzschild metric as the background geometry in the framework of classical polymerization. This process is an extension of the polymeric representation of quantum mechanics in such a way that a transformation maps classical variables to their polymeric counterpart. We show that the usual Schwarzschild metric can be extracted from a Hamiltonian function which in turn gets modifications due to the classical polymerization. Then, the polymer corrected Schwarzschild metric may be obtained by solving the polymer-Hamiltonian equations of motion. It is shown that while the conventional Schwarzschild space-time is a vacuum solution of the Einstein equations, its polymer-corrected version corresponds to an energy-momentum tensor that exhibits the features of dark energy. We also use the resulting metric to investigate some thermodynamical quantities associated with the Schwarzschild black hole, and in comparison with the standard Schwarzschild metric the similarities and differences are discussed. PubDate: Thu, 20 Sep 2018 00:00:00 +000

Abstract: The behaviour of massive and massless test particles around asymptotically flat and spherically symmetric, charged black holes in the context of generalized dilaton-axion gravity in four dimensions is studied. All the possible motions are investigated by calculating and plotting the corresponding effective potential for the massless and massive particles as well. Further, the motion of massive (charged or uncharged) test particles in the gravitational field of charged black holes in generalized dilaton-axion gravity for the cases of static and nonstatic equilibrium is investigated by applying the Hamilton-Jacobi approach. PubDate: Sun, 16 Sep 2018 06:44:07 +000

Abstract: The scintillating properties of active materials used in high energy and particle physics experiments play an important role regarding the performances of both calorimeters and experiments. Two scintillator materials, a scintillating glass and an inorganic crystals, were examined to be used for collider experiments showing good optical and scintillating properties. This paper discusses the simulated performances of two materials of interest assembled in a scintillator-photodetector combination. The computational study was carried out with Geant4 simulation program to determine energy resolutions of such calorimeter with different beam energies and calorimeter sizes. PubDate: Thu, 13 Sep 2018 00:00:00 +000

Abstract: We propose an alternative description of the Schwarzschild black hole based on the requirement that the solution is static not only outside the horizon but also inside it. As a consequence of this assumption, we are led to a change of signature implying a complex transformation of an angle variable. There is a “phase transition” on the surface , producing a change in the symmetry as we cross this surface. Some consequences of this situation on the motion of test particles are investigated. PubDate: Wed, 12 Sep 2018 06:35:10 +000

Abstract: We study the approximate scattering state solutions of the Duffin-Kemmer-Petiau equation (DKPE) and the spinless Salpeter equation (SSE) with the Hellmann potential. The eigensolutions, scattering phase shifts, partial-waves transitions, and the total cross section for all the partial waves are obtained and discussed. The dependence of partial-waves transitions on total angular momentum number, angular momentum number, mass combination, and potential parameters was presented in the figures. PubDate: Sun, 09 Sep 2018 08:16:12 +000

Abstract: We investigate the implications of a sterile neutrino on the physics potential of the proposed experiment DUNE and future runs of NOA using latest NOA results. Using combined analysis of the disappearance and appearance data, NOA reported preferred solutions at normal hierarchy (NH) with two degenerate best-fit points: one in the lower octant (LO) and = 1.48 and the other in higher octant (HO) and = 0.74. Another solution of inverted hierarchy (IH), which is 0.46 away from best fit, was also reported. We discuss chances of resolving these degeneracies in the presence of sterile neutrino. PubDate: Thu, 06 Sep 2018 06:53:22 +000

Abstract: In this work, we study the quantum system with the symmetric Razavy potential and show how to find its exact solutions. We find that the solutions are given by the confluent Heun functions. The eigenvalues have to be calculated numerically. The properties of the wave functions depending on are illustrated graphically for a given potential parameter . We find that the even and odd wave functions with definite parity are changed to odd and even wave functions when the potential parameter increases. This arises from the fact that the parity, which is a defined symmetry for very small , is completely violated for large . We also notice that the energy levels decrease with the increasing potential parameter . PubDate: Tue, 28 Aug 2018 08:58:56 +000

Abstract: Event detection rates for WIMP-nucleus interactions are calculated for Ga, Ge, As, and I (direct dark matter detectors). The nuclear structure form factors, which are rather independent of the underlying beyond the Standard Model particle physics scenario assumed, are evaluated within the context of the deformed nuclear shell model (DSM) based on Hartree-Fock nuclear states. Along with the previously published DSM results for Ge, the neutrino-floor due to coherent elastic neutrino-nucleus scattering (CENS), an important source of background to dark matter searches, is extensively calculated. The impact of new contributions to CENS due to neutrino magnetic moments and mediators at direct dark matter detection experiments is also examined and discussed. The results show that the neutrino-floor constitutes a crucial source of background events for multi-ton scale detectors with sub-keV capabilities. PubDate: Sun, 26 Aug 2018 06:51:26 +000

Abstract: We consider a cosmology with decaying metastable dark energy and assume that a decay process of this metastable dark energy is a quantum decay process. Such an assumption implies among others that the evolution of the Universe is irreversible and violates the time reversal symmetry. We show that if we replace the cosmological time appearing in the equation describing the evolution of the Universe by the Hubble cosmological scale time, then we obtain time dependent in the form of the series of even powers of the Hubble parameter :. Our special attention is focused on radioactive-like exponential form of the decay process of the dark energy and on the consequences of this type decay. PubDate: Sun, 19 Aug 2018 08:11:23 +000

Abstract: We propose a general expression for the probability distribution of real-valued tunneling times of a localized particle, as measured by the Salecker-Wigner-Peres quantum clock. This general expression is used to obtain the distribution of times for the scattering of a particle through a static rectangular barrier and for the tunneling decay of an initially bound state after the sudden deformation of the potential, the latter case being relevant to understand tunneling times in recent attosecond experiments involving strong field ionization. PubDate: Sun, 19 Aug 2018 06:59:49 +000

Abstract: Decaying vacuum cosmological models evolving smoothly between two extreme (very early and late time) de Sitter phases are able to solve or at least to alleviate some cosmological puzzles; among them we have (i) the singularity, (ii) horizon, (iii) graceful-exit from inflation, and (iv) the baryogenesis problem. Our basic aim here is to discuss how the coincidence problem based on a large class of running vacuum cosmologies evolving from de Sitter to de Sitter can also be mollified. It is also argued that even the cosmological constant problem becomes less severe provided that the characteristic scales of the two limiting de Sitter manifolds are predicted from first principles. PubDate: Thu, 16 Aug 2018 00:00:00 +000

Abstract: We study nonlinear cosmological perturbations and their possible non-Gaussian character in an extended nonminimal inflation where gravity is coupled nonminimally to both the scalar field and its derivatives. By expansion of the action up to the third order, we focus on the nonlinearity and non-Gaussianity of perturbations in comparison with recent observational data. By adopting an inflation potential of the form , we show that, for , for instance, this extended model is consistent with observation if in appropriate units. By restricting the equilateral amplitude of non-Gaussianity to the observationally viable values, the coupling parameter is constrained to the values . PubDate: Wed, 15 Aug 2018 00:00:00 +000

Abstract: The dual magnetohydrodynamics of dyonic plasma describes the study of electrodynamics equations along with the transport equations in the presence of electrons and magnetic monopoles. In this paper, we formulate the quaternionic dual fields equations, namely, the hydroelectric and hydromagnetic fields equations which are an analogous to the generalized Lamb vector field and vorticity field equations of dyonic cold plasma fluid. Further, we derive the quaternionic Dirac-Maxwell equations for dual magnetohydrodynamics of dyonic cold plasma. We also obtain the quaternionic dual continuity equations that describe the transport of dyonic fluid. Finally, we establish an analogy of Alfven wave equation which may generate from the flow of magnetic monopoles in the dyonic field of cold plasma. The present quaternionic formulation for dyonic cold plasma is well invariant under the duality, Lorentz, and CPT transformations. PubDate: Tue, 14 Aug 2018 06:07:43 +000

Abstract: We probe the shock wave geometry with the mutual correlation in a spherically symmetric Reissner-Nordström AdS black hole on the basis of the gauge/gravity duality. In the static background, we find that the regions living on the boundary of the AdS black holes are correlated provided the considered regions on the boundary are large enough. We also investigate the effect of the charge on the mutual correlation and find that the bigger the value of the charge is, the smaller the value of the mutual correlation will be. As a small perturbation is added at the AdS boundary, the horizon shifts and a dynamical shock wave geometry form after long time enough. In this dynamic background, we find that the greater the shift of the horizon is, the smaller the mutual correlation will be. Especially for the case that the shift is large enough, the mutual correlation vanishes, which implies that the considered regions on the boundary are uncorrelated. The effect of the charge on the mutual correlation in this dynamic background is found to be the same as that in the static background. PubDate: Mon, 13 Aug 2018 09:34:09 +000

Abstract: Accepting the Komar mass definition of a source with energy-momentum tensor and using the thermodynamic pressure definition, we find a relaxed energy-momentum conservation law. Thereinafter, we study some cosmological consequences of the obtained energy-momentum conservation law. It has been found out that the dark sectors of cosmos are unifiable into one cosmic fluid in our setup. While this cosmic fluid impels the universe to enter an accelerated expansion phase, it may even show a baryonic behavior by itself during the cosmos evolution. Indeed, in this manner, while behaves baryonically, a part of it, namely, which is satisfying the ordinary energy-momentum conservation law, is responsible for the current accelerated expansion. PubDate: Thu, 09 Aug 2018 08:15:03 +000

Abstract: We present another example of superfluid black hole containing phase transition in Horava gravity. After studying the extended thermodynamics of general dimensional Horava-Lifshitz AdS black holes, it is found that only the one with spherical horizon in four and five dimensions has phase transition, which is a line of (continuous) second-order phase transitions and was famous in the discussion of superfluidity of liquid . The “superfluid” black hole phase and “normal” black hole phase are also distinguished. Particularly, six-dimensional Horava-Lifshitz AdS black holes exhibit infinitely many critical points in plane and the divergent points for specific heat, for which they only contain the “normal” black hole phase and the “superfluid” black hole phase disappears due to the physical temperature constraint; therefore there is no similar phase transition. In more than six dimensions, there is no critical behavior. After choosing the appropriate ordering field, we study the critical phenomena in different planes of thermodynamical phase space. We also calculate the critical exponents, which are the same as the van der Waals fluid. PubDate: Thu, 09 Aug 2018 08:05:55 +000