Advances in High Energy Physics [SJR: 1.297] [H-I: 7]
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Open Access journal
ISSN (Print) 1687-7357 - ISSN (Online) 1687-7365
Published by Hindawi Publishing Corporation [368 journals]
- Searching for Neutrinoless Double-Beta Decay of 130Te with CUORE
Abstract: Neutrinoless double-beta (0) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0 decay of 130Te using an array of 988 TeO2 crystal bolometers operated at 10 mK. The detector will contain 206 kg of 130Te and have an average energy resolution of 5 keV; the projected 0 decay half-life sensitivity after five years of livetime is 1.6 × 1026 y at 1 (9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV). In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.
PubDate: Wed, 28 Jan 2015 12:41:15 +000
- Beyond Standard Model Searches in the MiniBooNE Experiment
Abstract: The MiniBooNE experiment has contributed substantially to beyond standard model searches in the neutrino sector. The experiment was originally designed to test the eV2 region of the sterile neutrino hypothesis by observing () charged current quasielastic signals from a () beam. MiniBooNE observed excesses of and candidate events in neutrino and antineutrino mode, respectively. To date, these excesses have not been explained within the neutrino standard model (SM); the standard model extended for three massive neutrinos. Confirmation is required by future experiments such as MicroBooNE. MiniBooNE also provided an opportunity for precision studies of Lorentz violation. The results set strict limits for the first time on several parameters of the standard-model extension, the generic formalism for considering Lorentz violation. Most recently, an extension to MiniBooNE running, with a beam tuned in beam-dump mode, is being performed to search for dark sector particles. This review describes these studies, demonstrating that short baseline neutrino experiments are rich environments in new physics searches.
PubDate: Wed, 28 Jan 2015 08:15:08 +000
- Regularization of Gravity Theories and Local Lorentz Transformation
Abstract: We regularized the field equations of gravity theories such that the effect of local Lorentz transformation (LLT), in the case of spherical symmetry, is removed. A “general tetrad field,” with an arbitrary function of radial coordinate preserving spherical symmetry, is provided. We split that tetrad field into two matrices; the first represents a LLT, which contains an arbitrary function, and the second matrix represents a proper tetrad field which is a solution to the field equations of gravitational theory (which are not invariant under LLT). This “general tetrad field” is then applied to the regularized field equations of . We show that the effect of the arbitrary function which is involved in the LLT invariably disappears.
PubDate: Mon, 26 Jan 2015 09:49:24 +000
- Minimal Length Effects on Tunnelling from Spherically Symmetric Black
Abstract: We investigate effects of the minimal length on quantum tunnelling from spherically symmetric black holes using the Hamilton-Jacobi method incorporating the minimal length. We first derive the deformed Hamilton-Jacobi equations for scalars and fermions, both of which have the same expressions. The minimal length correction to the Hawking temperature is found to depend on the black hole’s mass and the mass and angular momentum of emitted particles. Finally, we calculate a Schwarzschild black hole's luminosity and find the black hole evaporates to zero mass in infinite time.
PubDate: Thu, 22 Jan 2015 14:24:49 +000
- Direct Dark Matter Search
PubDate: Thu, 22 Jan 2015 11:46:56 +000
- Scalar Form Factor of the Pion in the Kroll-Lee-Zumino Field Theory
Abstract: The renormalizable Kroll-Lee-Zumino field theory of pions and a neutral rho-meson is used to determine the scalar form factor of the pion in the space-like region at next-to-leading order. Perturbative calculations in this framework are parameter-free, as the masses and the rho-pion-pion coupling are known from experiment. Results compare favorably with lattice QCD calculations.
PubDate: Wed, 21 Jan 2015 12:54:48 +000
- Retracted: Performance of Water-Based Liquid Scintillator: An Independent
PubDate: Tue, 20 Jan 2015 11:09:13 +000
- The DarkSide Multiton Detector for the Direct Dark Matter Search
Abstract: Although the existence of dark matter is supported by many evidences, based on astrophysical measurements, its nature is still completely unknown. One major candidate is represented by weakly interacting massive particles (WIMPs), which could in principle be detected through their collisions with ordinary nuclei in a sensitive target, producing observable low-energy (<100 keV) nuclear recoils. The DarkSide program aims at the WIPMs detection using a liquid argon time projection chamber (LAr-TPC). In this paper we quickly review the DarkSide program focusing in particular on the next generation experiment DarkSide-G2, a 3.6-ton LAr-TPC. The different detector components are described as well as the improvements needed to scale the detector from DarkSide-50 (50 kg LAr-TPC) up to DarkSide-G2. Finally, the preliminary results on background suppression and expected sensitivity are presented.
PubDate: Tue, 20 Jan 2015 09:20:42 +000
- Weyl-Invariant Extension of the Metric-Affine Gravity
Abstract: Metric-affine geometry provides a nontrivial extension of the general relativity where the metric and connection are treated as the two independent fundamental quantities in constructing the spacetime (with nonvanishing torsion and nonmetricity). In this paper, we study the generic form of action in this formalism and then construct the Weyl-invariant version of this theory. It is shown that, in Weitzenböck space, the obtained Weyl-invariant action can cover the conformally invariant teleparallel action. Finally, the related field equations are obtained in the general case.
PubDate: Tue, 20 Jan 2015 06:23:32 +000
- A Study of Universal Thermodynamics in Brane World Scenario
Abstract: A study of Universal thermodynamics is done in the framework of RSII brane model and DGP brane scenario. The Universe is chosen as FRW model bounded by apparent or event horizon. Assuming extended Hawking temperature on the horizon, the unified first law is examined for perfect fluid (with constant equation of state) and Modified Chaplygin Gas model. As a result there is a modification of Bekenstein entropy on the horizons. Further the validity of the generalized second law of thermodynamics and thermodynamical equilibrium are also investigated.
PubDate: Mon, 19 Jan 2015 09:38:10 +000
- Null Geodesics and Gravitational Lensing in a Nonsingular Spacetime
Abstract: The null geodesics and gravitational lensing in a nonsingular spacetime are investigated. According to the nature of the null geodesics, the spacetime is divided into several cases. In the weak deflection limit, we find the influence of the nonsingularity parameter on the positions and magnifications of the images is negligible. In the strong deflection limit, the coefficients and observables for the gravitational lensing in a nonsingular black hole background and a weakly nonsingular spacetime are obtained. Comparing these results, we find that, in a weakly nonsingular spacetime, the relativistic images have smaller angular position and relative magnification but larger angular separation than those of a nonsingular black hole. These results might offer a way to probe the spacetime nonsingularity parameter and put a bound on it by the astronomical instruments in the near future.
PubDate: Tue, 13 Jan 2015 12:28:07 +000
- Toy Models of Universe with an Effective Varying -Term in Lyra Manifold
Abstract: Research on the accelerated expansion of our Universe captures a lot of attention. The dark energy (DE) is a way to explain it. In this paper we will consider scalar field quintessence DE with EoS, where the dynamics of the DE models related to the dynamics of the scalar field. We are interested in the study of the behavior of the Universe in the presence of interacting quintessence DE models in Lyra manifold with a varying . In a considered framework we also would like to propose a new form for . We found that the models correspond to the transit Universe, which will enter the accelerated expansion phase and will remain there with a constant deceleration parameter . We found also that the is a decreasing function which takes a small positive value with and dominating in the old Universe. Observational constraints are applied and causality issue via is discussed as a possible way to either reject or accept the models.
PubDate: Mon, 12 Jan 2015 13:50:35 +000
- BPS Center Vortices in Nonrelativistic Gauge Models with Adjoint Higgs
Abstract: We propose a class of Yang-Mills models, with adjoint Higgs fields, that accept BPS center vortex equations. The lack of a local magnetic flux that could serve as an energy bound is circumvented by including a new term in the energy functional. This term tends to align, in the Lie algebra, the magnetic field and one of the adjoint Higgs fields. Finally, a reduced set of equations for the center vortex profile functions is obtained (for ). In particular, BPS vortices come in three colours and three anticolours, obtained from an ansatz based on the defining representation and its conjugate.
PubDate: Thu, 08 Jan 2015 07:20:09 +000
- Constraining the Parameters of Modified Chaplygin Gas in Einstein-Aether
Abstract: We have assumed FRW model of the universe in Einstein-Aether gravity filled with dark matter and modified Chaplygin gas (MCG) type dark energy. We present the Hubble parameter in terms of some unknown parameters and observational parameters with the redshift z. From observed Hubble data (OHD) set (12 points), we have obtained the bounds of the arbitrary parameters of MCG by minimizing the test. Next due to joint analysis of BAO and CMB observations, we have also obtained the best fit values and the bounds of the parameters by fixing some other parameters. We have also taken type Ia supernovae data set (union 2 data set with 557 data points). Next due to joint analysis with SNe, we have obtained the best fit values of parameters. The best fit values and bounds of the parameters are obtained by 66%, 90%, and 99% confidence levels for OHD, OHD + BAO, OHD + BAO + CMB, and OHD + BAO + CMB + SNe joint analysis. The distance modulus against redshift z for our theoretical MCG model in Einstein-Aether gravity has been tested for the best fit values of the parameters and the observed SNe Ia union2 data sample.
PubDate: Tue, 30 Dec 2014 00:10:20 +000
- CP Violation for in QCD Factorization
Abstract: In the QCD factorization (QCDF) approach we study the direct CP violation in via the mixing mechanism. We find that the CP violation can be enhanced by double mixing when the masses of the pairs are in the vicinity of the resonance, and the maximum CP violation can reach 28%. We also compare the results from the naive factorization and the QCD factorization.
PubDate: Wed, 24 Dec 2014 00:10:14 +000
- Gurzadyan’s Problem 5 and Improvement of Softenings for
Cosmological Simulations Using the PP Method
Abstract: This paper is devoted to different modifications of two standard softenings of the gravitational attraction (namely, the Plummer and Hernquist softenings), which are commonly used in cosmological simulations based on the particle-particle (PP) method, and their comparison. It is demonstrated that some of the proposed alternatives lead to almost the same accuracy as in the case of the pure Newtonian interaction, even despite the fact that the force resolution is allowed to equal half the minimum interparticle distance. The revealed way of precision improvement gives an opportunity to succeed in solving Gurzadyan’s Problem 5 and bring modern computer codes up to a higher standard.
PubDate: Mon, 22 Dec 2014 11:16:18 +000
- Cosmic Baryon Asymmetry in Different Neutrino Mass Models with Mixing
Abstract: We investigate the comparative studies of cosmological baryon asymmetry in different neutrino mass models with and without by considering the three-diagonal form of Dirac neutrino mass matrices and the three aspects of leptogenesis, unflavoured, flavoured, and nonthermal. We found that the estimations of any models with are consistent in all the three stages of calculations of leptogenesis and the results are better than the predictions of any models without which are consistent in a piecemeal manner with the observational data in all the three stages of leptogenesis calculations. For the normal hierarchy of Type-IA with charged lepton matrix, model with and without predicts inflaton mass required to produce the observed baryon asymmetry to be GeV and GeV, and the corresponding reheating temperatures are GeV and GeV respectively. These predictions are not in conflict with the gravitino problem which required the reheating temperature to be below GeV. And these values apply to the recent discovery of Higgs boson of mass 125 GeV. One can also have the right order of relic dark matter abundance only if the reheating temperature is bounded to below GeV.
PubDate: Sun, 21 Dec 2014 07:30:02 +000
- 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