Advances in High Energy Physics http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Emission of Protons and Charged Pions in p + Cu and p + Pb Collisions at 3, 8, and 15 GeV/c Sun, 20 Jul 2014 06:28:10 +0000 http://www.hindawi.com/journals/ahep/2014/675192/ We present an analysis of proton and charged pion transverse momentum spectra of and reactions at 3, 8, and 15 GeV/c in the framework of a multisource thermal model. The spectra are compared closely with the experimental data of HARP-CDP at all angular intervals. The result shows that the widths of the particle distributions in both and collisions decrease with increasing the angle for the same incident momentum. J. H. Kang, Y. C. Qian, B. C. Li, and S. W. Wu Copyright © 2014 J. H. Kang et al. All rights reserved. Common Behaviors of Spinor-Type Instantons in 2D Thirring and 4D Gursey Fermionic Models Thu, 17 Jul 2014 10:07:40 +0000 http://www.hindawi.com/journals/ahep/2014/148375/ We investigate two examples of conformal invariant pure spinor fermionic models, which admit particle-like solutions of the classical field equations. For different dimensions and quantum spinor numbers, the vector field visualizations of the models are constructed to provide a better understanding of the spinor-type instanton dynamics in phase space. The hierarchical cluster analysis method investigations of the models are also presented. Finally, the autocorrelation and power spectrum graphs of models are constructed and frequencies of motions are defined. Fatma Aydogmus and Eren Tosyali Copyright © 2014 Fatma Aydogmus and Eren Tosyali. All rights reserved. On Finite Interquark Potential in Driven by a Minimal Length Thu, 17 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/ahep/2014/142373/ We address the effect of a quantum gravity induced minimal length on a physical observable for three-dimensional Yang-Mills. Our calculation is done within stationary perturbation theory. Interestingly enough, we find an ultraviolet finite interaction energy, which contains a regularized logarithmic function and a linear confining potential. This result highlights the role played by the new quantum of length in our discussion. Patricio Gaete Copyright © 2014 Patricio Gaete. All rights reserved. Gaseous Detector with Sub-keV Threshold to Study Neutrino Scattering at Low Recoil Energies Tue, 15 Jul 2014 12:27:49 +0000 http://www.hindawi.com/journals/ahep/2014/147046/ Gaseous detector with a sub-keV electron equivalent threshold is a very perspective tool for the precision measurement of the neutrino magnetic moment and for observing coherent scattering of neutrinos on nuclei. The progress in the development of low noise electronics makes it possible to register the rare events at the threshold less than 100 eV. The construction of the gaseous detector is given and the typical pulses with amplitudes of a few eV observed on a bench scale installation are presented. The possible implications for future experiments are discussed. A. V. Kopylov, I. V. Orekhov, V. V. Petukhov, and A. E. Solomatin Copyright © 2014 A. V. Kopylov et al. All rights reserved. Scattering and Bound States of Duffin-Kemmer-Petiau Particles for -Parameter Hyperbolic Pöschl-Teller Potential Mon, 14 Jul 2014 12:11:09 +0000 http://www.hindawi.com/journals/ahep/2014/840907/ The Duffin-Kemmer-Petiau (DKP) equation in the presence of a scalar potential is solved in one spatial dimension for the vector -parameter Hyperbolic Pöschl-Teller (HPT) potential. In obtaining complete solutions we used the weak interaction approach and took the scalar and vector potentials in a correlated form. By looking at the asymptotic behaviors of the solutions, we identify the bound and scattering states. We calculate transmission () and reflection () probability densities and analyze their dependence on the potential shape parameters. Also we investigate the dependence of energy eigenvalues of the bound states on the potential shape parameters. Hilmi Yanar, Ali Havare, and Kenan Sogut Copyright © 2014 Hilmi Yanar et al. All rights reserved. Theory of Neutrino-Atom Collisions: The History, Present Status, and BSM Physics Thu, 10 Jul 2014 08:42:21 +0000 http://www.hindawi.com/journals/ahep/2014/569409/ An overview of the current theoretical studies on neutrino-atom scattering processes is presented. The ionization channel of these processes, which is studied in experiments searching for neutrino magnetic moments, is brought into focus. Recent developments in the theory of atomic ionization by impact of reactor antineutrinos are discussed. It is shown that the stepping approximation is well applicable for the data analysis practically down to the ionization threshold. Konstantin A. Kouzakov and Alexander I. Studenikin Copyright © 2014 Konstantin A. Kouzakov and Alexander I. Studenikin. All rights reserved. Dirac Particle for the Position Dependent Mass in the Generalized Asymmetric Woods-Saxon Potential Thu, 10 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/ahep/2014/973847/ The one-dimensional Dirac equation with position dependent mass in the generalized asymmetric Woods-Saxon potential is solved in terms of the hypergeometric functions. The transmission and reflection coefficients are obtained by considering the one-dimensional electric current density for the Dirac particle and the equation describing the bound states is found by utilizing the continuity conditions of the obtained wave function. Also, by using the generalized asymmetric Woods-Saxon potential solutions, the scattering states are found out without making calculation for the Woods-Saxon, Hulthen, cusp potentials, and so forth, which are derived from the generalized asymmetric Woods-Saxon potential and the conditions describing transmission resonances and supercriticality are achieved. At the same time, the data obtained in this work are compared with the results achieved in earlier studies and are observed to be consistent. Soner Alpdoğan and Ali Havare Copyright © 2014 Soner Alpdoğan and Ali Havare. All rights reserved. Chemical Potentials of Quarks Extracted from Particle Transverse Momentum Distributions in Heavy Ion Collisions at RHIC Energies Tue, 08 Jul 2014 09:18:48 +0000 http://www.hindawi.com/journals/ahep/2014/742193/ In the framework of a multisource thermal model, the transverse momentum distributions of charged particles produced in nucleus-nucleus (A-A) and deuteron-nucleus (d-A) collisions at relativistic heavy ion collider (RHIC) energies are investigated by a two-component revised Boltzmann distribution. The calculated results are in agreement with the PHENIX experimental data. It is found that the source temperature increases obviously with increase of the particle mass and incident energy, but it does not show an obvious change with the collision centrality. Then, the values of chemical potentials for up, down, and strange quarks can be obtained from the antiparticle to particle yield ratios in a wide transverse momentum range. The relationship between the chemical potentials of quarks and the transverse momentum with different centralities is investigated, too. Hong Zhao and Fu-Hu Liu Copyright © 2014 Hong Zhao and Fu-Hu Liu. All rights reserved. Transverse Momentum and Pseudorapidity Distributions of Charged Particles and Spatial Shapes of Interacting Events in Pb-Pb Collisions at 2.76 TeV Mon, 07 Jul 2014 07:51:29 +0000 http://www.hindawi.com/journals/ahep/2014/725739/ The transverse momentum and pseudorapidity distributions of charged particles produced in Pb-Pb collisions with different centrality intervals at center-of-mass energy per nucleon pair  TeV have been analyzed by using the improved multisource thermal model in which the whole interacting system and then the sources are described by the Tsallis statistics. The modelling results are in agreement with experimental data of the ALICE Collaboration. The rapidity distributions of charged particles are obtained according to the extracted parameter values. The shapes of interacting events (the dispersion plots of charged particles) are given in the momentum, rapidity, velocity, and coordinate spaces. Meanwhile, the event shapes in different spaces consisted by different transverse quantities and longitudinal quantities are presented. Fu-Hu Liu, Ya-Qin Gao, Tian Tian, and Bao-Chun Li Copyright © 2014 Fu-Hu Liu et al. All rights reserved. Eta Prime Gluonic Contribution to the Nucleon Self-Energy in an Effective Theory Mon, 07 Jul 2014 00:00:00 +0000 http://www.hindawi.com/journals/ahep/2014/841703/ We estimate a possible gluonic contribution to the self-energy of a nucleon in an effective theory. The couplings of the topological charge density to nucleons give rise to OZI violating -nucleon interactions. The one-loop self-energy of nucleon arising due to these interactions is studied using a heavy baryon chiral perturbation theory. The divergences have been removed using appropriate form factors. The nontrivial structure of the QCD vacuum has also been taken into account. The numerical results are sensitive to the choice of the regulator to a nonnegligible extent. We get the total contribution to the nucleon mass coming from its interaction with the topological charge density % of the nucleon mass. A. Upadhyay and J. P. Singh Copyright © 2014 A. Upadhyay and J. P. Singh. All rights reserved. Analytical BPS Maxwell-Higgs Vortices Wed, 02 Jul 2014 09:31:45 +0000 http://www.hindawi.com/journals/ahep/2014/210929/ We have established a prescription for the calculation of analytical vortex solutions in the context of generalized Maxwell-Higgs models whose overall dynamics is controlled by two positive functions of the scalar field, namely, and . We have also determined a natural constraint between these functions and the Higgs potential , allowing the existence of axially symmetric Bogomol'nyi-Prasad-Sommerfield (BPS) solutions possessing finite energy. Furthermore, when the generalizing functions are chosen suitably, the nonstandard BPS equations can be solved exactly. We have studied some examples, comparing them with the usual Abrikosov-Nielsen-Olesen (ANO) solution. The overall conclusion is that the analytical self-dual vortices are well-behaved in all relevant sectors, strongly supporting the consistency of the respective generalized models. In particular, our results mimic well-known properties of the usual (numerical) configurations, as localized energy density, while contributing to the understanding of topological solitons and their description by means of analytical methods. R. Casana, M. M. Ferreira Jr., E. da Hora, and C. dos Santos Copyright © 2014 R. Casana et al. All rights reserved. Anomalous Couplings in Collision at the LHC Wed, 02 Jul 2014 08:35:50 +0000 http://www.hindawi.com/journals/ahep/2014/935840/ We have examined the constraints on the anomalous    couplings through the process at the LHC by considering four forward detector acceptances: , , , and , where with and the energies of the photon and of the incoming proton, respectively. The sensitivity bounds on the anomalous couplings have been obtained at the 95% confidence level in a model independent effective Lagrangian approach. We have found that the bounds on these couplings can be highly improved compared to current experimental bounds. M. Köksal and S. C. İnan Copyright © 2014 M. Köksal and S. C. İnan. All rights reserved. Exact Solutions of the Dirac Hamiltonian on the Sphere under Hyperbolic Magnetic Fields Tue, 01 Jul 2014 11:44:53 +0000 http://www.hindawi.com/journals/ahep/2014/186425/ Two-dimensional massless Dirac Hamiltonian under the influence of hyperbolic magnetic fields is mentioned in curved space. Using a spherical surface parameterization, the Dirac operator on the sphere is presented and the system is given as two supersymmetric partner Hamiltonians which coincides with the position dependent mass Hamiltonians. We introduce two ansatzes for the component of the vector potential to acquire effective solvable models, which are Rosen-Morse II potential and the model given Midya and Roy, whose bound states are Jacobi type polynomials, and we adapt our work to these special models under some parameter restrictions. The energy spectrum and the eigenvectors are found for Rosen-Morse II potential. On the other hand, complete solutions are given for the second system. The vector and the effective potentials with their eigenvalues are sketched for each system. Özlem Yeşiltaş Copyright © 2014 Özlem Yeşiltaş. All rights reserved. Astronomical Signatures of Dark Matter Thu, 26 Jun 2014 00:00:00 +0000 http://www.hindawi.com/journals/ahep/2014/878203/ Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitting halos around many elliptical galaxies, and clusters of galaxies requiring a much larger component of unseen mass for the hot gas to be bound. The level of gravitational attraction needed for the spatial distribution of galaxies to evolve from the small perturbations implied by the very slightly anisotropic cosmic microwave background radiation to its current web-like configuration requires much more mass than is observed across the entire electromagnetic spectrum. Distorted shapes of galaxies and other features created by gravitational lensing in the images of many astronomical objects require an amount of dark matter consistent with other estimates. The unambiguous detection of dark matter and more recently evidence for dark energy has positioned astronomy at the frontier of fundamental physics as it was in the 17th century. Paul Gorenstein and Wallace Tucker Copyright © 2014 Paul Gorenstein and Wallace Tucker. All rights reserved. The Annual Modulation Signature for Dark Matter: DAMA/LIBRA-Phase1 Results and Perspectives Tue, 24 Jun 2014 00:00:00 +0000 http://www.hindawi.com/journals/ahep/2014/605659/ The results obtained with the total exposure of 1.04 ton × yr collected by DAMA/LIBRA-phase1 deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N. during 7 annual cycles are summarized. The DAMA/LIBRA-phase1 and the former DAMA/NaI data (cumulative exposure 1.33 ton × yr, corresponding to 14 annual cycles) give evidence at 9.3 σ C.L. for the presence of Dark Matter (DM) particles in the galactic halo, on the basis of the exploited model independent DM annual modulation signature by using highly radiopure NaI(Tl) target. The modulation amplitude of the single-hit events in the (2–6) keV energy interval is  cpd/kg/keV; the measured phase is days and the measured period is  yr; values are in a good well in agreement with those expected for DM particles. No systematic or side reactions able to mimic the exploited DM signature have been found or suggested by anyone over more than a decade. Some of the perspectives of the presently running DAMA/LIBRA-phase2 are outlined. Rita Bernabei, Pierluigi Belli, Fabio Cappella, Vincenzo Caracciolo, Simone Castellano, Riccardo Cerulli, Chang Jang Dai, Annelisa d’Angelo, Silio d’Angelo, Alessandro Di Marco, H. L. He, Antonella Incicchitti, H. H. Kuang, X. H. Ma, Francesco Montecchia, X. D. Sheng, Rui Guang Wang, and Zi-Piao Ye Copyright © 2014 Rita Bernabei et al. All rights reserved. Experimental Tests of Quantum Gravity and Exotic Quantum Field Theory Effects Mon, 23 Jun 2014 12:16:27 +0000 http://www.hindawi.com/journals/ahep/2014/192712/ Emil T. Akhmedov, Stephen Minter, Piero Nicolini, and Douglas Singleton Copyright © 2014 Emil T. Akhmedov et al. All rights reserved. Remarks on the Spin-One Duffin-Kemmer-Petiau Equation in the Presence of Nonminimal Vector Interactions in Dimensions Thu, 19 Jun 2014 12:47:50 +0000 http://www.hindawi.com/journals/ahep/2014/784072/ We point out a misleading treatment in the recent literature regarding analytical solutions for nonminimal vector interaction for spin-one particles in the context of the Duffin-Kemmer-Petiau (DKP) formalism. In those papers, the authors use improperly the nonminimal vector interaction endangering in their main conclusions. We present a few properties of the nonminimal vector interactions and also present the correct equations to this problem. We show that the solution can be easily found by solving Schrödinger-like equations. As an application of this procedure, we consider spin-one particles in presence of a nonminimal vector linear potential. L. B. Castro and L. P. de Oliveira Copyright © 2014 L. B. Castro and L. P. de Oliveira. All rights reserved. Nuclear Stopping in Central Au+Au Collisions at RHIC Energies Tue, 17 Jun 2014 09:02:29 +0000 http://www.hindawi.com/journals/ahep/2014/946934/ Nuclear stopping in central Au+Au collisions at relativistic heavy-ion collider (RHIC) energies is studied in the framework of a cascade mode and the modified ultrarelativistic quantum molecular dynamics (UrQMD) transport model. In the modified mode, the mean field potentials of both formed and “preformed” hadrons (from string fragmentation) are considered. It is found that the nuclear stopping is increasingly influenced by the mean-field potentials in the projectile and target regions with the increase of the reaction energy. In the central region, the calculations of the cascade model considering the modifying factor can describe the experimental data of the PHOBOS collaboration. Ying Yuan and Nana Guan Copyright © 2014 Ying Yuan and Nana Guan. All rights reserved. Neutrinos as Probes of Lorentz Invariance Mon, 16 Jun 2014 06:29:53 +0000 http://www.hindawi.com/journals/ahep/2014/962410/ Neutrinos can be used to search for deviations from exact Lorentz invariance. The worldwide experimental program in neutrino physics makes these particles a remarkable tool to search for a variety of signals that could reveal minute relativity violations. This paper reviews the generic experimental signatures of the breakdown of Lorentz symmetry in the neutrino sector. Jorge S. Díaz Copyright © 2014 Jorge S. Díaz. All rights reserved. Constraints on Heavy Neutrino and SUSY Parameters Derived from the Study of Neutrinoless Double Beta Decay Mon, 16 Jun 2014 00:00:00 +0000 http://www.hindawi.com/journals/ahep/2014/724315/ New constraints on the lepton number violating (LNV) parameters are derived from the analysis of the neutrinoless double beta () decay in the hypothesis that this process would occur through the exchange of heavy neutrinos and/or SUSY particles. For derivation, we use new values of both phase space factors (PSFs) and nuclear matrix elements (NMEs) calculated with numerical codes developed recently, as well as the most recent experimental lifetimes. The NMEs are computed with a shell model (ShM) code for , , and nuclei, while at present similar ShM results are available only for the first nucleus. We compare our results with similar ones from literature, obtained with ShM, QRPA, and IBM-2 methods, and conclude that more results are needed for a relevant analysis on the validity of NMEs associated with these decay mechanisms. Andrei Neacsu and Sabin Stoica Copyright © 2014 Andrei Neacsu and Sabin Stoica. All rights reserved. Searches for Dark Matter with Superheated Liquid Techniques Thu, 12 Jun 2014 00:00:00 +0000 http://www.hindawi.com/journals/ahep/2014/387493/ This is a short review of the detectors based on the superheated liquid techniques, including continuously sensitive bubble chambers, superheated droplet detectors (SDD) and Geysers. A. Pullia Copyright © 2014 A. Pullia. All rights reserved. A Note on Asymmetric Thick Branes Wed, 11 Jun 2014 12:42:06 +0000 http://www.hindawi.com/journals/ahep/2014/276729/ We study asymmetric thick braneworld scenarios, generated after adding a constant to the superpotential associated with the scalar field. We study in particular models with odd and even polynomial superpotentials, and we show that asymmetric brane can be generated irrespective of the potential being symmetric or asymmetric. We study in addition the nonpolynomial sine-Gordon like model, also constructed with the inclusion of a constant in the standard superpotential, and we investigate gravitational stability of the asymmetric brane. The results suggest robustness of the new braneworld scenarios and add further possibilities of the construction of asymmetric branes. D. Bazeia, R. Menezes, and R. da Rocha Copyright © 2014 D. Bazeia et al. All rights reserved. Physics of Quark Gluon Plasma: An Update and the Status Report Mon, 09 Jun 2014 06:26:11 +0000 http://www.hindawi.com/journals/ahep/2014/825041/ Jan E. Alam, Edward Sarkisyan-Grinbaum, and Subrata Bhattacharyya Copyright © 2014 Jan E. Alam et al. All rights reserved. Influence of Neutral Currents on Electron and Gamma Polarizations in the Process Thu, 05 Jun 2014 07:36:23 +0000 http://www.hindawi.com/journals/ahep/2014/217389/ The differential cross section of electron inelastic scattering by nuclei followed by γ radiation is calculated using the multipole decomposition of the hadronic currents and by taking into account the longitudinal polarization of the initial electron and the circular polarization of the γ radiation. We performed the analysis of the angular and energy dependence of the degree of electron and photon polarization which can yield information on values of weak neutral currents parameters. N. V. Samsonenko, Adamou Ousmane Manga, Almoustapha Aboubacar, and Aboubacar Moussa Copyright © 2014 N. V. Samsonenko et al. All rights reserved. Dark Atoms and Dark Radiation Wed, 04 Jun 2014 09:25:18 +0000 http://www.hindawi.com/journals/ahep/2014/913856/ Maxim Khlopov, Konstantin Belotsky, Jean-René Cudell, and Chris Kouvaris Copyright © 2014 Maxim Khlopov et al. All rights reserved. Dynamics of Interacting Tachyonic Teleparallel Dark Energy Tue, 03 Jun 2014 12:37:15 +0000 http://www.hindawi.com/journals/ahep/2014/631630/ We consider a tachyon scalar field which is nonminimally coupled to gravity in the framework of teleparallel gravity. We analyze the phase-space of the model, known as tachyonic teleparallel dark energy, in the presence of an interaction between dark energy and background matter. We find that although there exist some late-time accelerated attractor solutions, there is no scaling attractor. So, unfortunately interacting tachyonic teleparallel dark energy cannot alleviate the coincidence problem. Ali Banijamali Copyright © 2014 Ali Banijamali. All rights reserved. Black Holes Physics Wed, 28 May 2014 12:00:51 +0000 http://www.hindawi.com/journals/ahep/2014/453586/ Xiaoxiong Zeng, Christian Corda, and Deyou Chen Copyright © 2014 Xiaoxiong Zeng et al. All rights reserved. Constraints on Light Neutrino Parameters Derived from the Study of Neutrinoless Double Beta Decay Wed, 28 May 2014 11:00:15 +0000 http://www.hindawi.com/journals/ahep/2014/745082/ The study of the neutrinoless double beta decay mode can provide us with important information on the neutrino properties, particularly on the electron neutrino absolute mass. In this work we revise the present constraints on the neutrino mass parameters derived from the decay analysis of the experimentally interesting nuclei. We use the latest results for the phase space factors (PSFs) and nuclear matrix elements (NMEs), as well as for the experimental lifetime limits. For the PSFs we use values computed with an improved method reported very recently. For the NMEs we use values chosen from the literature on a case-by-case basis, taking advantage of the consensus reached by the community on several nuclear ingredients used in their calculation. Thus, we try to restrict the range of spread of the NME values calculated with different methods and, hence, to reduce the uncertainty in deriving limits for the Majorana neutrino mass parameter. Our results may be useful to have an updated image on the present neutrino mass sensitivities associated with measurements for different isotopes and to better estimate the range of values of the neutrino masses that can be explored in the future double beta decay (DBD) experiments. Sabin Stoica and Andrei Neacsu Copyright © 2014 Sabin Stoica and Andrei Neacsu. All rights reserved. Anomalous -Factors for Charged Leptons in a Fractional Coarse-Grained Approach Sun, 25 May 2014 12:54:31 +0000 http://www.hindawi.com/journals/ahep/2014/572180/ We here propose to extend the concept of helicity to include it in a fractional scenario and we write down the left- and the right-handed Weyl equations from first principles in this extended framework. Next, by coupling the different fractional Weyl sectors by means of a mass parameter, we arrive at the fractional version of Dirac's equation which, whenever coupled to an external electromagnetic field and reduced to the nonrelativistic regime, yields a fractional Pauli-type equation. From the latter, we are able to present an explicit expression for the gyromagnetic ratio of charged fermions in terms of the fractionality parameter. We then focus our efforts to relate the coarse-grained property of space-time to fractionality and to the () anomalies of the different leptonic species. J. Weberszpil and J. A. Helayël-Neto Copyright © 2014 J. Weberszpil and J. A. Helayël-Neto. All rights reserved. Study of and Decays via QCD Sum Rules Sun, 25 May 2014 12:16:41 +0000 http://www.hindawi.com/journals/ahep/2014/432903/ We present the calculation of the form factor of the and decays in the frame work of QCD sum rules. We also find branching ratio = which is in agreement with the experimental data. Furthermore, we estimate the  MeV, where experimental bound for full width of is  MeV. V. Bashiry Copyright © 2014 V. Bashiry. All rights reserved.