Advances in High Energy Physics
[SJR: 0.892] [H-I: 19] [21 followers] Follow
Open Access journal
ISSN (Print) 1687-7357 - ISSN (Online) 1687-7365
Published by Hindawi [333 journals]
- Experimental Results on Chiral Magnetic and Vortical Effects
Abstract: Various novel transport phenomena in chiral systems result from the interplay of quantum anomalies with magnetic field and vorticity in high-energy heavy-ion collisions and could survive the expansion of the fireball and be detected in experiments. Among them are the chiral magnetic effect, the chiral vortical effect, and the chiral magnetic wave, the experimental searches for which have aroused extensive interest. The goal of this review is to describe the current status of experimental studies at Relativistic Heavy-Ion Collider at BNL and the Large Hadron Collider at CERN and to outline the future work in experiment needed to eliminate the existing uncertainties in the interpretation of the data.
PubDate: Thu, 12 Jan 2017 00:00:00 +000
- Probe of the Anomalous Quartic Couplings with Beam Polarization at the
Abstract: We have investigated the anomalous quartic couplings defined by the dimension-8 operators in semileptonic decay channel of the process for unpolarized and polarized electron (positron) beam at the Compact Linear Collider. We give the 95% confidence level bounds on the anomalous , , and couplings for various values of the integrated luminosities and center-of-mass energies. The best sensitivities obtained on anomalous , , and couplings through the process with beam polarization at TeV and an integrated luminosity of are , , and , which show improvement over the current bounds.
PubDate: Wed, 11 Jan 2017 07:01:31 +000
- The Production of Neutral Resonance with Hidden Beauty from Scattering
Abstract: We investigate the discovery potential of the predicted neutral hidden beauty resonance through scattering within an effective Lagrangian approach. Two reactions and are studied in this work, with nucleon pole exchange as the background. It is found that the contributions of the resonance give clear peak structures in the magnitude of 1 near the threshold of in the total cross sections. The numerical results indicate that the center of mass energy GeV would be the best energy window for searching the resonance, where the signal can be easily distinguished from the background. The COMPASS experiment at CERN’s Super Proton Synchrotron (SPS) with pion beam of ≃280 GeV will be an ideal platform for searching the super-heavy resonance with hidden beauty, which is promising for testing the theoretical results.
PubDate: Tue, 03 Jan 2017 10:41:25 +000
- Analysis of Radial Excitations of Octet Baryons in QCD Sum Rules
Abstract: Using the QCD sum rules method, we estimate the mass and residues of the first radial excitations of octet baryons. The contributions coming from the ground state baryons are eliminated by constructing the linear combinations of the sum rules corresponding to different Lorentz structures. Our predictions of the masses of the first radial excitations of octet baryons are in good agreement with the data.
PubDate: Tue, 03 Jan 2017 08:32:39 +000
- Lévy Distributions for One-Dimensional Analysis of the
Abstract: A general study of relations between the parameters of two centrally symmetric Lévy distributions, often used for one-dimensional investigation of Bose–Einstein correlations, is given for the first time. These relations of the strength of correlations and of the radius of the emission region take into account possible various finite ranges of the Lorentz invariant four-momentum difference for two centrally symmetric Lévy distributions. In particular, special cases of the relations are investigated for Cauchy and normal (Gaussian) distributions. The mathematical formalism is verified using the recent measurements given that a generalized centrally symmetric Lévy distribution is used. The reasonable agreement is observed between estimations and experimental results for all available types of strong interaction processes and collision energies.
PubDate: Mon, 02 Jan 2017 09:30:28 +000
- Search for Excited Spin-3/2 Neutrinos at LHeC
Abstract: We study the potential of the next collider, namely, LHeC, with two options TeV and TeV, to search for excited spin-1/2 and spin-3/2 neutrinos. We calculate the single production cross-section of excited spin-1/2 and spin-3/2 neutrinos according to their effective currents describing their interactions between gauge bosons and SM leptons. We choose the decay mode of excited neutrinos and decay mode of -boson for the analysis. We put some kinematical cuts for the final state detectable particles and plot the invariant mass distributions for signal and the corresponding backgrounds. In order to obtain accessible limits for excited neutrino couplings, we show the and contour plots for excited spin-1/2 and excited spin-3/2 neutrinos, respectively.
PubDate: Thu, 29 Dec 2016 13:52:43 +000
- Supersymmetry, Supergravity, and Superstring Phenomenology
PubDate: Wed, 28 Dec 2016 14:25:20 +000
- Quantum Tunneling in Deformed Quantum Mechanics with Minimal Length
Abstract: In the deformed quantum mechanics with a minimal length, one WKB connection formula through a turning point is derived. We then use it to calculate tunneling rates through potential barriers under the WKB approximation. Finally, the minimal length effects on two examples of quantum tunneling in nuclear and atomic physics are discussed.
PubDate: Tue, 27 Dec 2016 12:26:13 +000
- Horizon Wavefunction of Generalized Uncertainty Principle Black Holes
Abstract: We study the Horizon Wavefunction (HWF) description of a Generalized Uncertainty Principle inspired metric that admits sub-Planckian black holes, where the black hole mass is replaced by . Considering the case of a wave-packet shaped by a Gaussian distribution, we compute the HWF and the probability that the source is a (quantum) black hole, that is, that it lies within its horizon radius. The case is qualitatively similar to the standard Schwarzschild case, and the general shape of is maintained when decreasing the free parameter but shifted to reduce the probability for the particle to be a black hole accordingly. The probability grows with increasing mass slowly for more negative and drops to 0 for a minimum mass value. The scenario differs significantly for increasing , where a minimum in is encountered, thus meaning that every particle has some probability of decaying to a black hole. Furthermore, for sufficiently large we find that every particle is a quantum black hole, in agreement with the intuitive effect of increasing , which creates larger and terms. This is likely due to a “dimensional reduction” feature of the model, where the black hole characteristics for sub-Planckian black holes mimic those in dimensions and the horizon size grows as .
PubDate: Tue, 27 Dec 2016 11:13:00 +000
- Remarks on the Static Potential Driven by Vacuum Nonlinearities in Models
Abstract: Within the framework of the gauge-invariant, but path-dependent, variables formalism, we study the manifestations of vacuum electromagnetic nonlinearities in models. For this we consider both generalized Born-Infeld and Pagels-Tomboulis-like electrodynamics, as well as Euler-Heisenberg-like electrodynamics. We explicitly show that generalized Born-Infeld and Pagels-Tomboulis-like electrodynamics are equivalent, where the static potential profile contains a long-range (-type) correction to the Coulomb potential. Interestingly enough, for Euler-Heisenberg-like electrodynamics the interaction energy contains a linear potential, leading to the confinement of static charges.
PubDate: Thu, 22 Dec 2016 14:32:43 +000
- Interacting Dark Matter and -Deformed Dark Energy Nonminimally Coupled to
Abstract: In this paper, we propose a new approach to study the dark sector of the universe by considering the dark energy as an emerging -deformed bosonic scalar field which is not only interacting with the dark matter, but also nonminimally coupled to gravity, in the framework of standard Einsteinian gravity. In order to analyze the dynamic of the system, we first give the quantum field theoretical description of the -deformed scalar field dark energy and then construct the action and the dynamical structure of this interacting and nonminimally coupled dark sector. As a second issue, we perform the phase-space analysis of the model to check the reliability of our proposal by searching the stable attractor solutions implying the late-time accelerating expansion phase of the universe.
PubDate: Thu, 22 Dec 2016 13:07:15 +000
- Propagating Degrees of Freedom in Gravity
Abstract: We have computed the number of polarization modes of gravitational waves propagating in the Minkowski background in gravity. These are three of two from transverse-traceless tensor modes and one from a massive trace mode, which confirms the results found in the literature. There is no massless breathing mode and the massive trace mode corresponds to the Ricci scalar. A newly defined metric tensor in gravity satisfies the transverse-traceless (TT) condition as well as the TT wave equation.
PubDate: Wed, 21 Dec 2016 14:15:02 +000
- Impact of Nonstandard Interactions on Neutrino-Nucleon Scattering
Abstract: Nonstandard neutrino-nucleon interaction is formulated and explored within the energy range of quasi-elastic scattering. In particular, the study focuses on the neutral-current elastic (anti)neutrino scattering off nucleons described by the exotic reactions and , which provide corrections to the dominant Standard Model processes. In this context, it is shown that the required exotic nucleon form factors may have a significant impact on the relevant cross sections. Besides cross sections, the event rate is expected to be rather sensitive to the magnitude of the lepton-flavour violating parameters resulting in an excess of events. The overlap of nonstandard interactions and strange quark contributions, in the region of few GeV neutrino energies, is also examined. The formalism is applied for the case of the relevant neutrino-nucleon scattering experiments (LSND, MiniBooNE, etc.) and motivates the notion that such facilities have high potential to probe NSI.
PubDate: Wed, 21 Dec 2016 13:31:21 +000
- The Calculation of Single-Nucleon Energies of Nuclei by Considering
Two-Body Effective Interaction, , and a Hartree-Fock Inspired Scheme
Abstract: The nucleon single-particle energies (SPEs) of the selected nuclei, that is, , , and , are obtained by using the diagonal matrix elements of two-body effective interaction, which generated through the lowest-order constrained variational (LOCV) calculations for the symmetric nuclear matter with the phenomenological nucleon-nucleon potential. The SPEs at the major levels of nuclei are calculated by employing a Hartree-Fock inspired scheme in the spherical harmonic oscillator basis. In the scheme, the correlation influences are taken into account by imposing the nucleon effective mass factor on the radial wave functions of the major levels. Replacing the density-dependent one-body momentum distribution functions of nucleons, , with the Heaviside functions, the role of in the nucleon SPEs at the major levels of the selected closed shell nuclei is investigated. The best fit of spin-orbit splitting is taken into account when correcting the major levels of the nuclei by using the parameterized Wood-Saxon potential and the density-dependent mean field potential which is constructed by the LOCV method. Considering the point-like protons in the spherical Coulomb potential well, the single-proton energies are corrected. The results show the importance of including , instead of the Heaviside functions, in the calculation of nucleon SPEs at the different levels, particularly the valence levels, of the closed shell nuclei.
PubDate: Mon, 19 Dec 2016 08:26:57 +000
- Curvature-Restored Gauge Invariance and Ultraviolet Naturalness
Abstract: It is shown that in a spacetime of curvature is a natural ultraviolet completion of in the flat-spacetime Standard Model with Higgs field , scale , and loop factors and . This curvature completion rests on the fact that -mass gauge theory in flat spacetime turns, on the cut view , into a massless gauge theory in curved spacetime. It provides a symmetry reason for curved spacetime, wherein gravity and matter are both low-energy effective phenomena. Gravity arises correctly if new physics exists with at least 63 more bosons than fermions, with no need to interact with the and with dark matter as a natural harbinger. It can source various cosmological, astrophysical, and collider phenomena depending on its spectrum and couplings to the .
PubDate: Wed, 07 Dec 2016 09:54:32 +000
- Quantum Treatment of Kinetic Alfvén Waves Instability in a Dusty
Plasma: Magnetized Ions
Abstract: Kinetic Alfvén wave instability is examined rigorously in a uniform nondegenerate quantum dusty plasma. A linear dispersion relation of kinetic Alfvén wave in inertial regime is derived by incorporating Bohm potential in the linearized Vlasov model. It is found that the quantum correction appears due to the insertion of Bohm potential in Vlasov model and causes the suppression in the Alfvén wave frequency and the growth rates of instability. A number of analytical expressions for various modes of propagation are derived. It is also found that the system parameters, that is, streaming velocity, dust charge, number density, and quantum correction, significantly influence the dispersion relation and the growth rate of instability.
PubDate: Wed, 07 Dec 2016 09:50:38 +000
- Spinor Quintom Cosmology with Intrinsic Spin
Abstract: We consider a spinor quintom dark energy model with intrinsic spin, in the framework of Einstein-Cartan-Sciama-Kibble theory. After constructing the mathematical formalism of the model, we obtain the spin contributed total energy-momentum tensor giving the energy density and the pressure of the quintom model, and then we find the equation of state parameter, Hubble parameter, deceleration parameter, state finder parameter, and some distance parameter in terms of the spinor potential. Choosing suitable potentials leads to the quintom scenario crossing between quintessence and phantom epochs, or vice versa. Analyzing three quintom scenarios provides stable expansion phases avoiding Big Rip singularities and yielding matter dominated era through the stabilization of the spinor pressure via spin contribution. The stabilization in spinor pressure leads to neglecting it as compared to the increasing energy density and constituting a matter dominated stable expansion epoch.
PubDate: Wed, 07 Dec 2016 09:40:30 +000
- Geometry and Space-Time Extent of Pion Emission Region at FCC Energies
Abstract: The energy dependence is investigated for a wide set of space-time characteristics derived from Bose–Einstein correlations of secondary pion pairs produced in proton-proton and nucleus-nucleus interactions. Analytic functions suggested for smooth approximations of the energy dependence of emission region parameters demonstrate reasonable agreement with all available experimental results for proton-proton collisions while the approximations correspond to most of experimental data for nucleus-nucleus collisions at energies above 5 GeV. Estimations for a wide set of space-time quantities are obtained for energies for the Future Circular Collider (FCC) project based on the smooth approximations. The space particle densities at freeze-out are derived also from estimations for the volume of the emission region and for total multiplicity at FCC energies. Estimations for charged particle density and its critical value allow the possibility of lasing behavior for secondary pions in nucleus-nucleus collisions at FCC energy. The mathematical formalism is presented for study of the peak shape of correlation function for general case of central-symmetrical Lévy–Feldheim distribution.
PubDate: Mon, 05 Dec 2016 14:15:41 +000
- High Efficiency Gaseous Tracking Detector for Cosmic Muon Radiography
Abstract: A tracking detector system has been constructed with an innovative approach to the classical multiwire proportional chamber concept, using contemporary technologies. The detectors, covering an area of 0.58 square meters each, are optimized for the application of muon radiography. The main features are high (>99.5%) and uniform detection efficiency, 9 mm FWHM position resolution, and filling gas consumption below 2 liters per hour for the nontoxic, nonflammable argon and carbon dioxide mixture. These parameters, along with the simplicity of the construction and the tolerance for mechanical effects, make the detectors a viable option for a large area muography observation system.
PubDate: Mon, 05 Dec 2016 06:19:09 +000
- Nuclear Structure Calculations for Two-Neutrino Double-β Decay
Abstract: We study the two-neutrino double- decay in 76Ge, 116Cd, 128Te, 130Te, and 150Nd, as well as the two Gamow-Teller branches that connect the double- decay partners with the states in the intermediate nuclei. We use a theoretical microscopic approach based on a deformed self-consistent mean field with Skyrme interactions including pairing and spin-isospin residual forces, which are treated in a proton-neutron quasiparticle random-phase approximation. We compare our results for Gamow-Teller strength distributions with experimental information obtained from charge-exchange reactions. We also compare our results for the two-neutrino double- decay nuclear matrix elements with those extracted from the measured half-lives. Both single-state and low-lying-state dominance hypotheses are analyzed theoretically and experimentally making use of recent data from charge-exchange reactions and decay of the intermediate nuclei.
PubDate: Thu, 01 Dec 2016 08:53:21 +000
- Kodama-Schwarzschild versus Gaussian Normal Coordinates Picture of Thin
Abstract: Geometry of the spacetime with a spherical shell embedded in it is studied in two coordinate systems: Kodama-Schwarzschild coordinates and Gaussian normal coordinates. We find explicit coordinate transformation between the Kodama-Schwarzschild and Gaussian normal coordinate systems. We show that projections of the metrics on the surface swept by the shell in the 4D spacetime in both cases are identical. In the general case of time-dependent metrics we calculate extrinsic curvatures of the shell in both coordinate systems and show that the results are identical. Applications to the Israel junction conditions are discussed.
PubDate: Mon, 28 Nov 2016 13:28:08 +000
- Universal Superspace Unitary Operator and Nilpotent (Anti-)Dual-BRST
Symmetries: Superfield Formalism
Abstract: We exploit the key concepts of the augmented version of superfield approach to Becchi-Rouet-Stora-Tyutin (BRST) formalism to derive the superspace (SUSP) dual unitary operator and its Hermitian conjugate and demonstrate their utility in the derivation of the nilpotent and absolutely anticommuting (anti-)dual-BRST symmetry transformations for a set of interesting models of the Abelian 1-form gauge theories. These models are the one ()-dimensional (1D) rigid rotor and modified versions of the two ()-dimensional (2D) Proca as well as anomalous gauge theories and 2D model of a self-dual bosonic field theory. We show the universality of the SUSP dual unitary operator and its Hermitian conjugate in the cases of all the Abelian models under consideration. These SUSP dual unitary operators, besides maintaining the explicit group structure, provide the alternatives to the dual horizontality condition (DHC) and dual gauge invariant restrictions (DGIRs) of the superfield formalism. The derivations of the dual unitary operators and corresponding (anti-)dual-BRST symmetries are completely novel results in our present investigation.
PubDate: Thu, 24 Nov 2016 13:18:51 +000
- Coupling -Deformed Dark Energy to Dark Matter
Abstract: We propose a novel coupled dark energy model which is assumed to occur as a -deformed scalar field and investigate whether it will provide an expanding universe phase. We consider the -deformed dark energy as coupled to dark matter inhomogeneities. We perform the phase-space analysis of the model by numerical methods and find the late-time accelerated attractor solutions. The attractor solutions imply that the coupled -deformed dark energy model is consistent with the conventional dark energy models satisfying an acceleration phase of universe. At the end, we compare the cosmological parameters of deformed and standard dark energy models and interpret the implications.
PubDate: Thu, 24 Nov 2016 11:48:39 +000
- Implications of and for Texture Specific Lepton Mass Matrices and Decay
Abstract: We study the phenomenological consequences of recent results from atmospheric and accelerator neutrino experiments, favoring normal neutrino mass ordering , a near maximal lepton Dirac CP phase along with , for possible realization of natural structure in the lepton mass matrices characterized by for . It is observed that deviations from parallel texture structures for and are essential for realizing such structures. In particular, such hierarchical neutrino mass matrices are not supportive for a vanishing neutrino mass characterized by and predict meV, , , , and , respectively, indicating that the task of observing a decay may be rather challenging for near future experiments.
PubDate: Tue, 22 Nov 2016 14:28:18 +000
- Beam Energy Dependence of Hanbury-Brown-Twiss Radii from a Blast-Wave
Abstract: The beam energy dependence of correlation lengths (the Hanbury-Brown-Twiss radii) is calculated by using a blast-wave model and the results are comparable with those from RHIC-STAR beam energy scan data as well as the LHC-ALICE measurements. A set of parameters for the blast-wave model as a function of beam energy under study are obtained by fit to the HBT radii at each energy point. The transverse momentum dependence of HBT radii is presented with the extracted parameters for Au+Au collision at = 200 GeV and for Pb+Pb collisions at 2.76 TeV. From our study one can learn that particle emission duration cannot be ignored while calculating the HBT radii with the same parameters. And tuning kinetic freeze-out temperature in a range will result in system lifetime changing in the reverse direction as it is found in RHIC-STAR experiment measurements.
PubDate: Tue, 22 Nov 2016 14:24:58 +000
- Axially Symmetric, Asymptotically Flat Vacuum Metric with a Naked
Singularity and Closed Timelike Curves
Abstract: We present an axially symmetric, asymptotically flat empty space solution of the Einstein field equations containing a naked singularity. The space-time is regular everywhere except on the symmetry axis where it possesses a true curvature singularity. The space-time is of type D in the Petrov classification scheme and is locally isometric to the metrics of case IV in the Kinnersley classification of type D vacuum metrics. Additionally, the space-time also shows the evolution of closed timelike curves (CTCs) from an initial hypersurface free from CTCs.
PubDate: Mon, 21 Nov 2016 14:33:21 +000
- The Effect of Chirped Intense Femtosecond Laser Pulses on the Argon
Abstract: The interaction of intense femtosecond laser pulses with atomic Argon clusters has been investigated by using nanoplasma model. Based on the dynamic simulations, ionization process, heating, and expansion of a cluster after irradiation by femtosecond laser pulses at intensities up to 2 1017 Wcm−2 are studied. The analytical calculation provides ionization rate for different mechanisms and time evolution of the density of electrons for different pulse shapes. In this approach, the strong dependence of laser intensity, pulse duration, and laser shape on the electron energy, the electron density, and the cluster size is presented using the intense chirped laser pulses. Based on the presented theoretical modifications, the effect of chirped laser pulse on the complex dynamical process of the interaction is studied. It is found that the energy of electrons and the radius of cluster for the negatively chirped pulses are improved up to 20% in comparison to the unchirped and positively chirped pulses.
PubDate: Mon, 21 Nov 2016 14:30:19 +000
- Indication of a Differential Freeze-Out in Proton-Proton and Heavy-Ion
Collisions at RHIC and LHC Energies
Abstract: The experimental data from the RHIC and LHC experiments of invariant spectra for most peripheral and collisions are analyzed with Tsallis distributions in different approaches. The information about the freeze-out surface in terms of freeze-out volume, temperature, chemical potential, and radial flow velocity for , , and and their antiparticles is obtained. Furthermore, these parameters are studied as a function of the mass of the particles. A mass dependent differential freeze-out is observed which does not seem to distinguish between particles and their antiparticles. Furthermore, a mass-hierarchy in the radial flow is observed, meaning heavier particles suffer lower radial flow. Tsallis distribution function at finite chemical potential is used to study the mass dependence of chemical potential. The peripheral heavy-ion and proton-proton collisions at the same energies seem to be equivalent in terms of the extracted thermodynamic parameters.
PubDate: Tue, 15 Nov 2016 12:25:57 +000
- Search for Anomalous Quartic Couplings in Photon-Photon Collisions
Abstract: The self-couplings of the electroweak gauge bosons are completely specified by the non-Abelian gauge nature of the Standard Model (SM). The direct study of these couplings provides a significant opportunity to test the validity of the SM and the existence of new physics beyond the SM up to the high energy scale. For this reason, we investigate the potential of the processes , , and to examine the anomalous quartic couplings of vertex at the Compact Linear Collider (CLIC) with center-of-mass energy 3 TeV. We calculate confidence level sensitivities on the dimension-8 parameters with various values of the integrated luminosity. We show that the best bounds on the anomalous , , , and couplings arising from process among those three processes at center-of-mass energy of 3 TeV and integrated luminosity of fb−1 are found to be TeV−4, TeV−4, TeV−4, and TeV−4, respectively.
PubDate: Mon, 14 Nov 2016 12:31:35 +000
- Properties of Quasi-Oscillator in Position-Dependent Mass Formalism
Abstract: Schrödinger equation is considered within position-dependent mass formalism with a quasi-oscillator interaction term. Wave functions and energy spectra have been obtained analytically. Thermodynamic properties, information entropy, and uncertainty in coordinate and momentum spaces are calculated. To provide a better physical insight into the solutions, some figures are included.
PubDate: Sun, 13 Nov 2016 13:32:14 +000