Advances in High Energy Physics
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Open Access journal
ISSN (Print) 1687-7357 - ISSN (Online) 1687-7365
Published by Hindawi Publishing Corporation [365 journals] [SJR: 1.297] [H-I: 7]
- Effects of Noncommutativity on the Black Hole Entropy
Abstract: The BTZ black hole geometry is probed with a noncommutative scalar field which obeys the κ-Minkowski algebra. The entropy of the BTZ black hole is calculated using the brick wall method. The contribution of the noncommutativity to the black hole entropy is explicitly evaluated up to the first order in the deformation parameter. We also argue that such a correction to the black hole entropy can be interpreted as arising from the renormalization of the Newton’s constant due to the effects of the noncommutativity.
PubDate: Thu, 16 Oct 2014 08:42:46 +000
- Spinless Particles in Exponentially Varying Electric and Magnetic Fields
Abstract: We investigate the motion of the charged spin-0 particles subjected to the space-dependent electric and magnetic fields. By selecting the external fields oriented parallel and orthogonal to each other, exact solutions of the motion are obtained for the nonrelativistic and the relativistic cases. The quantized energy spectrum is determined by using the solutions obtained for the motion of the particles and dependence of the energy on the strengths of the electric and magnetic fields is discussed. We compared the energy spectrum of the nonrelativistic and the relativistic particles by using the numerical results obtained for the first few quantum levels.
PubDate: Wed, 15 Oct 2014 08:26:25 +000
- Classical Bianchi Type I Cosmology in K-Essence Theory
Abstract: We use one of the simplest forms of the K-essence theory and we apply it to the classical anisotropic Bianchi type I cosmological model, with a barotropic perfect fluid () modeling the usual matter content and with cosmological constant . Classical exact solutions for any and are found in closed form, whereas solutions for are found for particular values in the barotropic parameter. We present the possible isotropization of the cosmological model Bianchi I using the ratio between the anisotropic parameters and the volume of the universe. We also include a qualitative analysis of the analog of the Friedmann equation.
PubDate: Tue, 14 Oct 2014 08:20:47 +000
- Probing Features of the Lee-Wick Quantum Electrodynamics
Abstract: We discuss some aspects concerning the electromagnetic sector of the abelian Lee-Wick (LW) quantum electrodynamics (QED). Using the Dirac’s theory of constrained systems, the higher-order canonical quantization of the LW electromagnetism is performed. A quantum bound on the LW heavy mass is also estimated using the best known measurement of the anomalous magnetic moment of the electron. Finally, it is shown that magnetic monopoles can coexist peacefully in the LW scenario.
PubDate: Mon, 13 Oct 2014 11:43:11 +000
- Semileptonic Transition of Tensor to Meson
Abstract: Taking into account the two-gluon condensate corrections, the transition form factors of the semileptonic decay channel are calculated via three-point QCD sum rules. These form factors are used to estimate the decay width of the transition under consideration in both electron and muon channels. The obtained results can be used both in direct search for such decay channels at charm factories and in analysis of the Bc meson decay at LHC.
PubDate: Mon, 13 Oct 2014 07:15:18 +000
- Reconstructions of Einstein-Aether Gravity from Ordinary and
Entropy-Corrected Versions of Holographic and New Agegraphic Dark Energy
Abstract: Here we briefly discuss the Einstein-Aether gravity theory by modification of Einstein-Hilbert action. We find the modified Friedmann equations and then from the equations we find the effective density and pressure for Einstein-Aether gravity sector. These can be treated as if dark energy provided some restrictions on the free function , where is proportional to . Assuming two types of the power law solutions of the scale factor, we have reconstructed the unknown function from HDE and NADE and their entropy-corrected versions (ECHDE and ECNADE). We also obtain the EoS parameter for Einstein-Aether gravity dark energy. For HDE and NADE, we have shown that the type I scale factor generates the quintessence scenario only and type II scale factor generates phantom scenario. But for ECHDE and ECNADE, both types of scale factors can accommodate the transition from quintessence to phantom stages; that is, phantom crossing is possible for entropy-corrected terms of HDE and NADE models. Finally, we show that the models are classically unstable.
PubDate: Sun, 12 Oct 2014 12:50:10 +000
- Regge Poles in Neutron Scattering by a Cylinder
Abstract: We establish asymptotic expressions for the positions of Regge poles for cold neutron scattering on mesoscopic cylinder mirror as well as for the -matrix residuals. We outline the correspondence between Regge poles and near-surface quasi-stationary neutron states. Such states are of practical importance for studying subtle effects of neutron-surface interaction.
PubDate: Tue, 16 Sep 2014 09:23:35 +000
- FRW Cosmology with the Extended Chaplygin Gas
Abstract: We propose extended Chaplygin gas equation of state for which it recovers barotropic fluid with quadratic equation of state. We use numerical method to investigate the behavior of some cosmological parameters such as scale factor, Hubble expansion parameter, energy density, and deceleration parameter. We also discuss the resulting effective equation of state parameter. Using density perturbations we investigate the stability of the theory.
PubDate: Mon, 15 Sep 2014 08:47:22 +000
- A Field Theory with Curvature and Anticurvature
Abstract: The present work is an attempt to construct a unified field theory in a space with curvature and anticurvature, the PAP-space. The theory is derived from an action principle and a Lagrangian density using a symmetric linear parameterized connection. Three different methods are used to explore physical contents of the theory obtained. Poisson’s equations for both material and charge distributions are obtained, as special cases, from the field equations of the theory. The theory is a pure geometric one in the sense that material distribution, charge distribution, gravitational and electromagnetic potentials, and other physical quantities are defined in terms of pure geometric objects of the structure used. In the case of pure gravity in free space, the spherical symmetric solution of the field equations gives the Schwarzschild exterior field. The weak equivalence principle is respected only in the case of pure gravity in free space; otherwise it is violated.
PubDate: Sun, 14 Sep 2014 08:05:35 +000
- Study of Baryon Spectroscopy Using a New Potential Form
Abstract: In the present work, the nonrelativistic quark model is applied to study baryon systems, where the constituent quarks are bound by a suitable hyper central potential. We proposed a new phenomenological form of the interaction potential, digamma-type potential. Using the Jacobi coordinates, the three-body wave equation is solved numerically to calculate the resonance states of the , and baryon systems. The present model contains only two adjustable parameters in addition to the quark masses. Our theoretical calculations are compared to the available experimental data and Cornell potential results. The description of the spectrum shows that the ground states of the considered light and strange baryon spectra are in general well reproduced.
PubDate: Wed, 10 Sep 2014 13:18:01 +000
- Method of Studying Decays with One Missing Particle
Abstract: A new technique is discussed that can be applied to baryon decays where decays with one missing particle can be discerned from background and their branching fractions determined, along with other properties of the decays. Applications include measurements of the CKM elements and and detection of any exotic objects coupling to decays, such as the inflaton. Potential use of and to investigate decays is also commented upon.
PubDate: Wed, 10 Sep 2014 09:36:03 +000
- Precision Measurement of the Position-Space Wave Functions of
Gravitationally Bound Ultracold Neutrons
Abstract: Gravity is the most familiar force at our natural length scale. However, it is still exotic from the view point of particle physics. The first experimental study of quantum effects under gravity was performed using a cold neutron beam in 1975. Following this, an investigation of gravitationally bound quantum states using ultracold neutrons was started in 2002. This quantum bound system is now well understood, and one can use it as a tunable tool to probe gravity. In this paper, we review a recent measurement of position-space wave functions of such gravitationally bound states and discuss issues related to this analysis, such as neutron loss models in a thin neutron guide, the formulation of phase space quantum mechanics, and UCN position sensitive detectors. The quantum modulation of neutron bound states measured in this experiment shows good agreement with the prediction from quantum mechanics.
PubDate: Wed, 10 Sep 2014 07:20:56 +000
- Schwarzschild-de Sitter and Anti-de Sitter Thin-Shell Wormholes and Their
Abstract: This paper is devoted to construct Schwarzschild-de Sitter and anti-de Sitter thin-shell wormholes by employing Visser’s cut and paste technique. The Darmois-Israel formalism is adopted to formulate the surface stresses of the shell. We analyze null and weak energy conditions as well as attractive and repulsive characteristics of thin-shell wormholes. We also explore stable and unstable solutions against linear perturbations by taking two different Chaplygin gas models for exotic matter. It is concluded that the stress-energy tensor components violate the null and weak energy conditions indicating the existence of exotic matter at the wormhole throat. Finally, we find unstable and stable configurations for the constructed thin-shell wormholes.
PubDate: Tue, 09 Sep 2014 12:17:18 +000
- Error-Disturbance Uncertainty Relations in Neutron-Spin Measurements
Abstract: In his seminal paper, which was published in 1927, Heisenberg originally introduced a relation between the precision of a measurement and the disturbance it induces onto another measurement. Here, we report a neutron-optical experiment that records the error of a spin-component measurement as well as the disturbance caused on a measurement of another spin-component to test error-disturbance uncertainty relations (EDRs). We demonstrate that Heisenberg’s original EDR is violated and the Ozawa and Branciard EDRs are valid in a wide range of experimental parameters.
PubDate: Mon, 08 Sep 2014 05:44:43 +000
- The Scattering and Bound States of the Schrödinger Particle in
Generalized Asymmetric Manning-Rosen Type Potential
Abstract: We solve exactly one-dimensional Schrödinger equation for the generalized asymmetric Manning-Rosen (GAMAR) type potential containing the different types of physical potential that have many application fields in the nonrelativistic quantum mechanics and obtain the solutions in terms of the Gauss hypergeometric functions. Then we determine the solutions for scattering and bound states. By using these states we calculate the reflection and transmission coefficients for scattering states and achieve a correlation that gives the energy eigenvalues for the bound states. In addition to these, we show how the transmission and reflection coefficients depend on the parameters which describe shape of the GAMAR type potential and compare our results with the results obtained in earlier studies.
PubDate: Sun, 07 Sep 2014 07:07:51 +000
- Importance of Nonperturbative QCD Parameters for Bottom Mesons
Abstract: The importance of nonperturbative quantum chromodynamics (QCD) parameters is discussed in context to the predicting power for bottom meson masses and isospin splitting. In the framework of heavy quark effective theory, the work presented here focuses on the different allowed values of the two nonperturbative QCD parameters used in heavy quark effective theory formula, and using the best fitted parameter, masses of the excited bottom meson states in doublet in strange and nonstrange sectors are calculated here. The calculated masses are found to be matching well with experiments and other phenomenological models. The mass splitting and hyperfine splitting have also been analyzed for both strange and nonstrange heavy mesons with respect to spin and flavor symmetries.
PubDate: Wed, 03 Sep 2014 11:49:54 +000
- Pion Spectra in Collisions as a Function of and Event Multiplicity
Abstract: We study the charged pion transverse momentum spectra in collisions as a function of collision energy and event multiplicity using Tsallis distribution. This study gives an insight of the pion production process in collisions. The study covers pion spectra measured in collisions at SPS energies (6.27–17.27 GeV), RHIC energies (62.4 GeV and 200 GeV), and LHC energies (900 GeV, 2.76 TeV, and 7 TeV). The Tsallis parameters have been obtained and parameterized as a function of . The study suggests that as we move to higher energy more and more hard processes contribute to the spectra. We also study the charged pion spectra for different event multiplicities in collisions for LHC energies using Tsallis distribution. The variation of the Tsallis parameters as a function of event multiplicity has been obtained and their behavior is found to be independent of collision energy.
PubDate: Tue, 02 Sep 2014 12:49:52 +000
- Holographic Renormalization in Dense Medium
Abstract: The holographic renormalization of a charged black brane with or without a dilaton field, whose dual field theory describes a dense medium at finite temperature, is investigated in this paper. In a dense medium, two different thermodynamic descriptions are possible due to an additional conserved charge. These two different thermodynamic ensembles are classified by the asymptotic boundary condition of the bulk gauge field. It is also shown that in the holographic renormalization regularity of all bulk fields can reproduce consistent thermodynamic quantities and that the Bekenstein-Hawking entropy is nothing but the renormalized thermal entropy of the dual field theory. Furthermore, we find that the Reissner-Nordström AdS black brane is dual to a theory with conformal matter as expected, whereas a charged black brane with a nontrivial dilaton profile is mapped to a theory with nonconformal matter although its leading asymptotic geometry still remains as AdS space.
PubDate: Tue, 02 Sep 2014 12:30:30 +000
- CνB Damping of Primordial Gravitational Waves and the Fine-Tuning of
the CγB Temperature Anisotropy
Abstract: Damping of primordial gravitational waves due to the anisotropic stress contribution owing to the cosmological neutrino background (CνB) is investigated in the context of a radiation-to-matter dominated universe. Besides its inherent effects on the gravitational wave propagation, the inclusion of the CνB anisotropic stress into the dynamical equations also affects the tensor mode contribution to the anisotropy of the cosmological microwave background (CγB) temperature. The mutual effects on the gravitational waves and on the CγB are obtained through a unified prescription for a radiation-to-matter dominated scenario. The results are confronted with some preliminary results for the radiation dominated scenario. Both scenarios are supported by a simplified analytical framework, in terms of a scale independent dynamical variable, kη, that relates cosmological scales, k, and the conformal time, η. The background relativistic (hot dark) matter essentially works as an effective dispersive medium for the gravitational waves such that the damping effect is intensified for the universe evolving to the matter dominated era. Changes on the temperature variance owing to the inclusion of neutrino collision terms into the dynamical equations result in spectral features that ratify that the multipole expansion coefficients ’s die out for .
PubDate: Mon, 01 Sep 2014 05:51:03 +000
- Interacting Quintessence Dark Energy Models in Lyra Manifold
Abstract: We consider two-component dark energy models in Lyra manifold. The first component is assumed to be a quintessence field while the second component may be a viscous polytropic gas, a viscous Van der Waals gas, or a viscous modified Chaplygin gas. We also consider the possibility of interaction between components. By using the numerical analysis, we study some cosmological parameters of the models and compare them with observational data.
PubDate: Mon, 01 Sep 2014 00:00:00 +000
- Quantum Haplodynamics, Dark Matter, and Dark Energy
Abstract: In quantum haplodynamics (QHD) the weak bosons, quarks, and leptons are bound states of fundamental constituents, denoted as haplons. The confinement scale of the associated gauge group is of the order of TeV. One scalar state has zero haplon number and is the resonance observed at the LHC. In addition, there exist new bound states of haplons with no counterpart in the SM, having a mass of the order of 0.5 TeV up to a few TeV. In particular, a neutral scalar state with haplon number 4 is stable and can provide the dark matter in the universe. The QHD, QCD, and QED couplings can unify at the Planck scale. If this scale changes slowly with cosmic time, all of the fundamental couplings, the masses of the nucleons and of the DM particles, including the cosmological term (or vacuum energy density), will evolve with time. This could explain the dark energy of the universe.
PubDate: Sun, 31 Aug 2014 09:00:41 +000
- On Descriptions of Particle Transverse Momentum Spectra in High Energy
Abstract: The transverse momentum spectra obtained in the frame of an isotropic emission source are compared in terms of Tsallis, Boltzmann, Fermi-Dirac, and Bose-Einstein distributions and the Tsallis forms of the latter three standard distributions. It is obtained that, at a given set of parameters, the standard distributions show a narrower shape than their Tsallis forms which result in wide and/or multicomponent spectra with the Tsallis distribution in between. A comparison among the temperatures obtained from the distributions is made with a possible relation to the Boltzmann temperature. An example of the angular distributions of projectile fragments in nuclear collisions is given.
PubDate: Thu, 28 Aug 2014 11:32:18 +000
- Testing a Dilaton Gravity Model Using Nucleosynthesis
Abstract: Big bang nucleosynthesis (BBN) offers one of the most strict evidences for the -CDM cosmology at present, as well as the cosmic microwave background (CMB) radiation. In this work, our main aim is to present the outcomes of our calculations related to primordial abundances of light elements, in the context of higher dimensional steady-state universe model in the dilaton gravity. Our results show that abundances of light elements (primordial D, 3He, 4He, T, and 7Li) are significantly different for some cases, and a comparison is given between a particular dilaton gravity model and -CDM in the light of the astrophysical observations.
PubDate: Wed, 27 Aug 2014 08:38:29 +000
- A Systematic Study of Magnetic Field in Relativistic Heavy-Ion Collisions
in the RHIC and LHC Energy Regions
Abstract: The features of magnetic field in relativistic heavy-ion collisions are systematically studied by using a modified magnetic field model in this paper. The features of magnetic field distributions in the central point are studied in the RHIC and LHC energy regions. We also predict the feature of magnetic fields at LHC , 2760, and 7000 GeV based on the detailed study at RHIC , 130, and 200 GeV. The dependencies of the features of magnetic fields on the collision energies, centralities, and collision time are systematically investigated, respectively.
PubDate: Tue, 26 Aug 2014 06:27:04 +000
- Residual Symmetries Applied to Neutrino Oscillations at NOA and T2K
Abstract: The results previously obtained from the model-independent application of a generalized hidden horizontal symmetry to the neutrino mass matrix are updated using the latest global fits for the neutrino oscillation parameters. The resulting prediction for the Dirac phase is in agreement with recent results from T2K. The distribution for the Jarlskog invariant has become sharper and appears to be approaching a particular region. The approximate effects of matter on long-baseline neutrino experiments are explored, and it is shown how the weak interactions between the neutrinos and the particles that make up the Earth can help to determine the mass hierarchy. A similar strategy is employed to show how NOA and T2K could determine the octant of . Finally, the exact effects of matter are obtained numerically in order to make comparisons with the form of the approximate solutions. From this analysis there emerge some interesting features of the effective mass eigenvalues.
PubDate: Sun, 24 Aug 2014 12:18:54 +000
- Gravitational Resonance Spectroscopy with an Oscillating Magnetic Field
Gradient in the GRANIT Flow through Arrangement
Abstract: Gravitational resonance spectroscopy consists in measuring the energy spectrum of bouncing ultracold neutrons above a mirror by inducing resonant transitions between different discrete quantum levels. We discuss how to induce the resonances with a flow through arrangement in the GRANIT spectrometer, excited by an oscillating magnetic field gradient. The spectroscopy could be realized in two distinct modes (so called DC and AC) using the same device to produce the magnetic excitation. We present calculations demonstrating the feasibility of the newly proposed AC mode.
PubDate: Sun, 24 Aug 2014 09:40:55 +000
- Magnetized Anisotropic Dark Energy Models in Barber’s Second
Abstract: The present paper deals with Bianchi type IX cosmological model with magnetized anisotropic dark energy by using Barber’s self-creation theory. The energy momentum tensor consists of anisotropic fluid with EoS parameter and a uniform magnetic field of energy density . In order to obtain the exact solution we have assumed that dark energy components and the components of magnetic field interact minimally and obey the law of conservation of energy momentum tensors. We have also used the special law of variation for the mean generalized Hubble parameter and power law relation between scalar field and scale factor. Some physical and kinematical properties of the models have been discussed.
PubDate: Sun, 24 Aug 2014 09:37:03 +000
- Tests of Lorentz Symmetry in Single Beta Decay
Abstract: Low-energy experiments studying single beta decay can serve as sensitive probes of Lorentz invariance that can complement interferometric searches for deviations from this spacetime symmetry. Experimental signatures of a dimension-three operator for Lorentz violation which are unobservable in neutrino oscillations are described for the decay of polarized and unpolarized neutrons as well as for measurements of the spectral endpoint in beta decay.
PubDate: Sun, 24 Aug 2014 09:11:25 +000
- Study of Confinement/Deconfinement Transition in AdS/QCD with Generalized
Abstract: We study analytical solutions of charged black holes and thermally charged AdS with generalized warped factors in Einstein-Maxwell-Dilaton system. We calculate Euclidean action for charged AdS and thermally charged AdS. The actions in both backgrounds are regularized by the method of background subtraction. The study of phase transition between charged black hole and thermally charged AdS gives an insight into the confinement/deconfinement transition. The plots of grand potential versus temperature and chemical potential versus transition temperature are obtained.
PubDate: Thu, 21 Aug 2014 11:14:14 +000
- Lorentz Violation of the Photon Sector in Field Theory Models
Abstract: We compare the Lorentz violation terms of the pure photon sector between two field theory models, namely, the minimal standard model extension (SME) and the standard model supplement (SMS). From the requirement of the identity of the intersection for the two models, we find that the free photon sector of the SMS can be a subset of the photon sector of the minimal SME. We not only obtain some relations between the SME parameters but also get some constraints on the SMS parameters from the SME parameters. The CPT-odd coefficients of the SME are predicted to be zero. There are 15 degrees of freedom in the Lorentz violation matrix of free photons of the SMS related with the same number of degrees of freedom in the tensor coefficients , which are independent from each other in the minimal SME but are interrelated in the intersection of the SMS and the minimal SME. With the related degrees of freedom, we obtain the conservative constraints on the elements of the photon Lorentz violation matrix. The detailed structure of the photon Lorentz violation matrix suggests some applications to the Lorentz violation experiments for photons.
PubDate: Thu, 21 Aug 2014 06:30:58 +000