Advances in High Energy Physics The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Spherically Symmetric Solution in (1+4)-Dimensional Gravity Theories Thu, 23 Oct 2014 13:06:24 +0000 A nondiagonal spherically symmetric tetrad field, involving four unknown functions of radial coordinate plus an angle , which is a generalization of the azimuthal angle , is applied to the field equations of (1+4)-dimensional gravity theory. A special vacuum solution with one constant of integration is derived. The physical meaning of this constant is shown to be related to the gravitational mass of the system and the associated metric represents Schwarzschild in (1+4)-dimension. The scalar torsion related to this solution vanishes. We put the derived solution in a matrix form and rewrite it as a product of three matrices: the first represents a rotation while the second represents an inertia and the third matrix is the diagonal square root of Schwarzschild spacetime in (1+4)-dimension. Gamal G. L. Nashed Copyright © 2014 Gamal G. L. Nashed. All rights reserved. Identification of Parton Pairs in a Dijet Event and Investigation of Its Effects on Dijet Resonance Search Tue, 21 Oct 2014 00:00:00 +0000 Being able to distinguish parton pair type in a dijet event could significantly improve the search for new particles that are predicted by the theories beyond the Standard Model at the Large Hadron Collider. To explore whether parton pair types manifesting themselves as a dijet event could be distinguished on an event-by-event basis, I performed a simulation based study considering observable jet variables. I found that using a multivariate approach can filter out about 80% of the other parton pairs while keeping more than half of the quark-quark or gluon-gluon parton pairs in an inclusive QCD dijet distribution. The effects of event-by-event parton pair tagging for dijet resonance searches were also investigated and I found that improvement on signal significance after applying parton pair tagging can reach up to 4 times for gluon-gluon resonances. Sertac Ozturk Copyright © 2014 Sertac Ozturk. All rights reserved. Langevin Diffusion in Holographic Backgrounds with Hyperscaling Violation Mon, 20 Oct 2014 09:09:02 +0000 We consider a relativistic heavy quark which moves in the quark-gluon plasmas. By using the holographic methods, we analyze the Langevin diffusion process of this relativistic heavy quark. This heavy quark is described by a trailing string attached to a flavor brane and moving at constant velocity. The fluctuations of this string are related to the thermal correlators and the correlation functions are precisely the kinds of objects that we compute in the gravity dual picture. We obtain the action of the trailing string in hyperscaling violation backgrounds and we then find the equations of motion. These equations lead us to constructing the Langevin correlator which helps us to obtain the Langevin constants. Using the Langevin correlators we derive the spectral densities and simple analytic expressions in the small- and large-frequency limits. We examine our works for planar and -charged black holes with hyperscaling violation and find new constraints on in the presence of velocity . J. Sadeghi and F. Pourasadollah Copyright © 2014 J. Sadeghi and F. Pourasadollah. All rights reserved. Rotating Dilaton Black Strings Coupled to Exponential Nonlinear Electrodynamics Mon, 20 Oct 2014 00:00:00 +0000 We construct a new class of charged rotating black string solutions coupled to dilaton and exponential nonlinear electrodynamic fields with cylindrical or toroidal horizons in the presence of a Liouville-type potential for the dilaton field. Due to the presence of the dilaton field, the asymptotic behaviors of these solutions are neither flat nor (A)dS. We analyze the physical properties of the solutions in detail. We compute the conserved and thermodynamic quantities of the solutions and verify the first law of thermodynamics on the black string horizon. When the nonlinear parameter goes to infinity, our results reduce to those of black string solutions in Einstein-Maxwell-dilaton gravity. Ahmad Sheykhi Copyright © 2014 Ahmad Sheykhi. All rights reserved. Effects of Noncommutativity on the Black Hole Entropy Thu, 16 Oct 2014 08:42:46 +0000 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. Kumar S. Gupta, E. Harikumar, Tajron Jurić, Stjepan Meljanac, and Andjelo Samsarov Copyright © 2014 Kumar S. Gupta et al. All rights reserved. Spinless Particles in Exponentially Varying Electric and Magnetic Fields Wed, 15 Oct 2014 08:26:25 +0000 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. Kenan Sogut and Ali Havare Copyright © 2014 Kenan Sogut and Ali Havare. All rights reserved. Classical Bianchi Type I Cosmology in K-Essence Theory Tue, 14 Oct 2014 08:20:47 +0000 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. J. Socorro, Luis O. Pimentel, and Abraham Espinoza-García Copyright © 2014 J. Socorro et al. All rights reserved. Probing Features of the Lee-Wick Quantum Electrodynamics Mon, 13 Oct 2014 11:43:11 +0000 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. R. Turcati and M. J. Neves Copyright © 2014 R. Turcati and M. J. Neves. All rights reserved. Semileptonic Transition of Tensor to Meson Mon, 13 Oct 2014 07:15:18 +0000 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. J. Y. Sungu, H. Sundu, and K. Azizi Copyright © 2014 J. Y. Sungu et al. All rights reserved. Reconstructions of Einstein-Aether Gravity from Ordinary and Entropy-Corrected Versions of Holographic and New Agegraphic Dark Energy Models Sun, 12 Oct 2014 12:50:10 +0000 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. Ujjal Debnath Copyright © 2014 Ujjal Debnath. All rights reserved. Regge Poles in Neutron Scattering by a Cylinder Tue, 16 Sep 2014 09:23:35 +0000 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. K. V. Protasov and A. Y. Voronin Copyright © 2014 K. V. Protasov and A. Y. Voronin. All rights reserved. FRW Cosmology with the Extended Chaplygin Gas Mon, 15 Sep 2014 08:47:22 +0000 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. B. Pourhassan and E. O. Kahya Copyright © 2014 B. Pourhassan and E. O. Kahya. All rights reserved. A Field Theory with Curvature and Anticurvature Sun, 14 Sep 2014 08:05:35 +0000 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. M. I. Wanas and Mona M. Kamal Copyright © 2014 M. I. Wanas and Mona M. Kamal. All rights reserved. Study of Baryon Spectroscopy Using a New Potential Form Wed, 10 Sep 2014 13:18:01 +0000 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. L. I. Abou-Salem Copyright © 2014 L. I. Abou-Salem. All rights reserved. Method of Studying Decays with One Missing Particle Wed, 10 Sep 2014 09:36:03 +0000 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. Sheldon Stone and Liming Zhang Copyright © 2014 Sheldon Stone and Liming Zhang. All rights reserved. Precision Measurement of the Position-Space Wave Functions of Gravitationally Bound Ultracold Neutrons Wed, 10 Sep 2014 07:20:56 +0000 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. Y. Kamiya, G. Ichikawa, and S. Komamiya Copyright © 2014 Y. Kamiya et al. All rights reserved. Schwarzschild-de Sitter and Anti-de Sitter Thin-Shell Wormholes and Their Stability Tue, 09 Sep 2014 12:17:18 +0000 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. M. Sharif and Saadia Mumtaz Copyright © 2014 M. Sharif and Saadia Mumtaz. All rights reserved. Error-Disturbance Uncertainty Relations in Neutron-Spin Measurements Mon, 08 Sep 2014 05:44:43 +0000 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. Stephan Sponar, Georg Sulyok, Jaqueline Erhart, and Yuji Hasegawa Copyright © 2014 Stephan Sponar et al. All rights reserved. The Scattering and Bound States of the Schrödinger Particle in Generalized Asymmetric Manning-Rosen Type Potential Sun, 07 Sep 2014 07:07:51 +0000 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. Ahmet Taş, Soner Alpdoğan, and Ali Havare Copyright © 2014 Ahmet Taş et al. All rights reserved. Importance of Nonperturbative QCD Parameters for Bottom Mesons Wed, 03 Sep 2014 11:49:54 +0000 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. A. Upadhyay and M. Batra Copyright © 2014 A. Upadhyay and M. Batra. All rights reserved. Pion Spectra in Collisions as a Function of and Event Multiplicity Tue, 02 Sep 2014 12:49:52 +0000 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. Priyanka Sett and Prashant Shukla Copyright © 2014 Priyanka Sett and Prashant Shukla. All rights reserved. Holographic Renormalization in Dense Medium Tue, 02 Sep 2014 12:30:30 +0000 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. Chanyong Park Copyright © 2014 Chanyong Park. All rights reserved. CνB Damping of Primordial Gravitational Waves and the Fine-Tuning of the CγB Temperature Anisotropy Mon, 01 Sep 2014 05:51:03 +0000 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 . A. E. Bernardini and J. F. G. Santos Copyright © 2014 A. E. Bernardini and J. F. G. Santos. All rights reserved. Interacting Quintessence Dark Energy Models in Lyra Manifold Mon, 01 Sep 2014 00:00:00 +0000 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. M. Khurshudyan, J. Sadeghi, R. Myrzakulov, Antonio Pasqua, and H. Farahani Copyright © 2014 M. Khurshudyan et al. All rights reserved. Quantum Haplodynamics, Dark Matter, and Dark Energy Sun, 31 Aug 2014 09:00:41 +0000 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. Harald Fritzsch and Joan Solà Copyright © 2014 Harald Fritzsch and Joan Solà. All rights reserved. On Descriptions of Particle Transverse Momentum Spectra in High Energy Collisions Thu, 28 Aug 2014 11:32:18 +0000 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. Fu-Hu Liu, Ya-Qin Gao, and Hua-Rong Wei Copyright © 2014 Fu-Hu Liu et al. All rights reserved. Testing a Dilaton Gravity Model Using Nucleosynthesis Wed, 27 Aug 2014 08:38:29 +0000 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. S. Boran and E. O. Kahya Copyright © 2014 S. Boran and E. O. Kahya. All rights reserved. A Systematic Study of Magnetic Field in Relativistic Heavy-Ion Collisions in the RHIC and LHC Energy Regions Tue, 26 Aug 2014 06:27:04 +0000 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. Yang Zhong, Chun-Bin Yang, Xu Cai, and Sheng-Qin Feng Copyright © 2014 Yang Zhong et al. All rights reserved. Residual Symmetries Applied to Neutrino Oscillations at NOA and T2K Sun, 24 Aug 2014 12:18:54 +0000 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. Andrew D. Hanlon, Wayne W. Repko, and Duane A. Dicus Copyright © 2014 Andrew D. Hanlon et al. All rights reserved. Gravitational Resonance Spectroscopy with an Oscillating Magnetic Field Gradient in the GRANIT Flow through Arrangement Sun, 24 Aug 2014 09:40:55 +0000 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. G. Pignol, S. Baeßler, V. V. Nesvizhevsky, K. Protasov, D. Rebreyend, and A. Voronin Copyright © 2014 G. Pignol et al. All rights reserved.