Advances in High Energy Physics
[13 followers] Follow
Open Access journal
ISSN (Print) 1687-7357 - ISSN (Online) 1687-7365
Published by Hindawi Publishing Corporation [366 journals] [SJR: 1.297] [H-I: 7]
- Massive Conformal Gravity
Abstract: We construct a massive theory of gravity that is invariant under conformal transformations. The massive action of the theory depends on the metric tensor and a scalar field, which are considered the only field variables. We find the vacuum field equations of the theory and analyze its weak-field approximation and Newtonian limit.
PubDate: Sun, 14 Dec 2014 08:11:37 +000
- Minimal Length and the Existence of Some Infinitesimal Quantities in
Quantum Theory and Gravity
Abstract: It is demonstrated that provided a theory involves a minimal length, this theory must be free from such infinitesimal quantities as infinitely small variations in surface of the holographic screen, its volume, and entropy. The corresponding infinitesimal quantities in this case must be replaced by the “minimal variations possible”—finite quantities dependent on the existent energies. As a result, the initial low-energy theory (quantum theory or general relativity) inevitably must be replaced by a minimal length theory that gives very close results but operates with absolutely other mathematical apparatus.
PubDate: Wed, 10 Dec 2014 06:56:02 +000
- Irreversible Thermodynamics of the Universe: Constraints from Planck Data
Abstract: The present work deals with irreversible universal thermodynamics. The homogenous and isotropic flat model of the universe is chosen as open thermodynamical system and nonequilibrium thermodynamics comes into picture. For simplicity, entropy flow is considered only due to heat conduction. Further, due to Maxwell-Cattaneo modified Fourier law for nonequilibrium phenomenon, the temperature satisfies damped wave equation instead of heat conduction equation. Validity of generalized second law of thermodynamics (GSLT) has been investigated for universe bounded by apparent or event horizon with cosmic substratum as perfect fluid with constant or variable equation of state or interacting dark species. Finally, we have used three Planck data sets to constrain the thermal conductivity λ and the coupling parameter . These constraints must be satisfied in order for GSLT to hold for universe bounded by apparent or event horizons.
PubDate: Thu, 04 Dec 2014 12:33:11 +000
- Interaction between Dark Matter and Dark Energy and the Cosmological
Abstract: We consider a quintessence model of dark energy inspired by scalar-tensor theories of gravity where the scalar field is nonminimally coupled to gravity and dark matter. By considering exponential potential as self-interaction potential, the stability and existence of the critical points are discussed in details. With nonminimally coupled dark sector with gravity, we obtain scaling solutions to address the coincidence problem by considering complex velocity for dark matter. The statefinder diagnostic shows that the equation of state reaches model in the future.
PubDate: Tue, 02 Dec 2014 09:54:32 +000
- Dirac Equation under Scalar and Vector Generalized Isotonic Oscillators
and Cornell Tensor Interaction
Abstract: Spin and pseudospin symmetries of Dirac equation are solved under scalar and vector generalized isotonic oscillators and Cornell potential as a tensor interaction for arbitrary quantum number via the analytical ansatz approach. The spectrum of the system is numerically reported for typical values of the potential parameters.
PubDate: Sun, 30 Nov 2014 11:40:33 +000
- Galactic Halo Wormhole Solutions in Gravity
Abstract: The proposal of galactic halo region is based on the idea that dark halos contain some characteristics needed to support traversable wormhole solutions. We explore wormhole solutions in this region in the framework of generalized teleparallel gravity. We consider static spherically symmetric wormhole spacetime with flat galactic rotational curves and obtain expressions of matter components for nondiagonal tetrad. The effective energy-momentum tensor leads to the violation of energy conditions which may impose condition on the normal matter to satisfy these conditions. We take two well-known models in exponential and logarithmic forms to discuss wormhole solutions as well as the equilibrium condition. It is concluded that wormhole solutions violating weak energy condition are obtained for both models with stable configuration.
PubDate: Thu, 27 Nov 2014 13:22:03 +000
- Chemical Evolution of Strongly Interacting Quark-Gluon Plasma
Abstract: At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (1 fm/c). However, the quark-gluon plasma (QGP) system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperature MeV to MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations.
PubDate: Mon, 24 Nov 2014 14:00:25 +000
- Perihelion Precession and Deflection of Light in the General Spherically
Abstract: The perihelion precession and deflection of light have been investigated in the 4-dimensional general spherically symmetric spacetime, and the master equation is obtained. As the application of this master equation, the Reissner-Nordstorm-AdS solution and Clifton-Barrow solution in gravity have been taken as examples. We find that both the electric charge and gravity can affect the perihelion precession and deflection of light, while the cosmological constant can only effect the perihelion precession. Moreover, we clarify a subtlety in the deflection of light in the solar system that the possible sun’s electric charge is usually used to interpret the gap between the experiment data and theoretical result. However, after also considering the effect from the sun’s same electric charge on the perihelion precession of Mercury, we can find that it is not the truth.
PubDate: Mon, 24 Nov 2014 13:50:06 +000
- Novel Quantum Encryption Algorithm Based on Multiqubit Quantum Shift
Register and Hill Cipher
Abstract: Based on a quantum shift register, a novel quantum block cryptographic algorithm that can be used to encrypt classical messages is proposed. The message is encoded and decoded by using a code generated by the quantum shift register. The security of this algorithm is analysed in detail. It is shown that, in the quantum block cryptographic algorithm, two keys can be used. One of them is the classical key that is used in the Hill cipher algorithm where Alice and Bob use the authenticated Diffie Hellman key exchange algorithm using the concept of digital signature for the authentication of the two communicating parties and so eliminate the man-in-the-middle attack. The other key is generated by the quantum shift register and used for the coding of the encryption message, where Alice and Bob share the key by using the BB84 protocol. The novel algorithm can prevent a quantum attack strategy as well as a classical attack strategy. The problem of key management is discussed and circuits for the encryption and the decryption are suggested.
PubDate: Mon, 24 Nov 2014 13:24:04 +000
- An Analytical Study of the Nonsinglet Spin Structure Function Up to NLO in
the DGLAP Approach at Small
Abstract: A next-to-leading order QCD calculation of nonsinglet spin structure function at small is presented using the analytical methods: Lagrange’s method and method of characteristics. The compatibility of these analytical approaches is tested by comparing the analytical solutions with the available polarized global fits.
PubDate: Sun, 23 Nov 2014 12:47:23 +000
- Equal Area Laws and Latent Heat for -Dimensional RN-AdS Black Hole
Abstract: We study the equal area laws of -dimensional RN-AdS black hole. We choose two kinds of phase diagrams, and . We employ the equal area laws to find an isobar which is the real two-phase coexistence line. Our calculation is much simpler to derive the critical value of the thermodynamic quantities. According to the thermodynamic quantities, we also study the latent heat of the black hole.
PubDate: Wed, 19 Nov 2014 09:39:22 +000
- The Effect of Nuclear Elastic Scattering on Temperature Equilibration Rate
of Ions in Fusion Plasma
Abstract: A plasma with two different particle types and at different temperatures has been considered, so that each type of ion with Maxwell-Boltzmann distribution function is in temperature equilibrium with itself. Using the extracted nuclear elastic scattering differential cross-section from experimental data, solving the Boltzmann equation, and also taking into account the mobility of the background particles, temperature equilibration rate between two different ions in a fusion plasma is calculated. The results show that, at higher temperature differences, effect of nuclear elastic scattering is more important in calculating the temperature equilibration rate. The obtained expressions have general form so that they are applicable to each type of particle for background () and each type for projectile (). In this paper, for example, an equimolar Deuterium-Hydrogen plasma with density cm−3 is chosen in which the deuteron is the background particle with temperature (also electron temperature) keV (usual conditions for a fusion plasma at the ignition instant) and the proton is the projectile with temperature . These calculations, particularly, are very important for ion fast ignition in inertial confinement fusion concept.
PubDate: Mon, 17 Nov 2014 00:00:00 +000
- Extracting the QCD Cutoff Parameter Using the Bernstein Polynomials and
the Truncated Moments
Abstract: Since there are not experimental data over the whole range of -Bjorken variable, that is, , we are inevitable in practice to do the integration for Mellin moments over the available range of experimental data. Among the methods of analysing DIS data, there are the methods based on application of Mellin moments. We use the truncated Mellin moments rather than the usual moments to analyse the EMC collaboration data for muon-nucleon and WA25 data for neutrino-deuterium DIS scattering. How to connect the truncated Mellin moments to usual ones is discussed. Following that we combine the truncated Mellin moments with the Bernstein polynomials. As a result, Bernstein averages which are related to different orders of the truncated Mellin moment are obtained. These averaged quantities can be considered as the constructed experimental data. By accessing the sufficient experimental data we can do the fitting more precisely. We do the fitting at leading order and next-to-leading order approximations to extract the QCD cutoff parameter. The results are in good agreement with what is being expected.
PubDate: Tue, 11 Nov 2014 12:16:24 +000
- Field Equations and Radial Solutions in a Noncommutative Spherically
Abstract: We study a noncommutative theory of gravity in the framework of torsional spacetime. This theory is based on a Lagrangian obtained by applying the technique of dimensional reduction of noncommutative gauge theory and that the yielded diffeomorphism invariant field theory can be made equivalent to a teleparallel formulation of gravity. Field equations are derived in the framework of teleparallel gravity through Weitzenbock geometry. We solve these field equations by considering a mass that is distributed spherically symmetrically in a stationary static spacetime in order to obtain a noncommutative line element. This new line element interestingly reaffirms the coherent state theory for a noncommutative Schwarzschild black hole. For the first time, we derive the Newtonian gravitational force equation in the commutative relativity framework, and this result could provide the possibility to investigate examples in various topics in quantum and ordinary theories of gravity.
PubDate: Tue, 11 Nov 2014 10:23:12 +000
- Probing the Top Quark Flavour-Changing Neutral Current at a Future
Abstract: We present a study to examine the sensitivity of a future collider to the anomalous top flavour-changing neutral current (FCNC) to the gluon. To separate signal from background a multivariate analysis is performed on top quark pair and background events, where one top quark is considered to follow the dominant standard model (SM) decay, , and the other top decays through FCNC, , where is a - or a -quark. The analysis of fully hadronic FCNC decay of the pair is also presented. The 95% confidence level limits on the top quark anomalous couplings are obtained for different values of the center-of-mass energies and integrated luminosities.
PubDate: Mon, 03 Nov 2014 07:11:07 +000
- Correspondence of Modified Gravity with Scalar Field Models
Abstract: This paper is devoted to study the scalar field dark energy models by taking its different aspects in the framework of gravity. We consider flat FRW universe to construct the equation of state parameter governed by gravity. The stability of the model is discussed with the help of squared speed of sound parameter. It is found that models show quintessence behavior of the universe in stable as well as unstable modes. We also develop the correspondence of model with some scalar field dark energy models like quintessence, tachyonic field, k-essence, dilaton, hessence, and DBI-essence. The nature of scalar fields and corresponding scalar potentials is being analyzed in gravity graphically which show consistency with the present day observations about accelerated phenomenon.
PubDate: Sun, 02 Nov 2014 08:01:34 +000
- Fractional Quantum Field Theory: From Lattice to Continuum
Abstract: An approach to formulate fractional field theories on unbounded lattice space-time is suggested. A fractional-order analog of the lattice quantum field theories is considered. Lattice analogs of the fractional-order 4-dimensional differential operators are proposed. We prove that continuum limit of the suggested lattice field theory gives a fractional field theory for the continuum 4-dimensional space-time. The fractional field equations, which are derived from equations for lattice space-time with long-range properties of power-law type, contain the Riesz type derivatives on noninteger orders with respect to space-time coordinates.
PubDate: Thu, 30 Oct 2014 10:20:33 +000
- Investigation of the Rare Exclusive Decays in the Framework of the QCD Sum
Abstract: Exclusive decay is studied in the framework of the three-point QCD sum rules approach. The two gluon condensate contributions to the correlation function are calculated and the form factors of this transition are found. The decay width and total branching ratio for this decay are also calculated.
PubDate: Mon, 27 Oct 2014 08:49:23 +000
- Development of a Liquid Scintillator Using Water for a Next Generation
Abstract: A feasibility study on a new type of liquid scintillator based on water has been performed. Mainly due to the differences in polarities between water and oil, organic solvents are not mixed in water. In order to make a liquid scintillator based on water, a surfactant that contains hydrophilic and hydrophobic groups is used. The surfactant keeps water and organic solvents apart in solution. Good physical and optical parameters and long-term stability are required to use liquid scintillator based on water in massive detector for the next generation neutrino experiments. In this paper, we report the characteristics and the possibility of liquid scintillators using water with various new surfactants.
PubDate: Mon, 27 Oct 2014 00:00:00 +000
- Spherically Symmetric Solution in (1+4)-Dimensional Gravity Theories
Abstract: 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.
PubDate: Thu, 23 Oct 2014 13:06:24 +000
- Identification of Parton Pairs in a Dijet Event and Investigation of Its
Effects on Dijet Resonance Search
Abstract: 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.
PubDate: Tue, 21 Oct 2014 00:00:00 +000
- Langevin Diffusion in Holographic Backgrounds with Hyperscaling Violation
Abstract: 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 .
PubDate: Mon, 20 Oct 2014 09:09:02 +000
- Rotating Dilaton Black Strings Coupled to Exponential Nonlinear
Abstract: 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.
PubDate: Mon, 20 Oct 2014 00:00:00 +000
- 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