Advances in High Energy Physics
[SJR: 1.334] [H-I: 12] [16 followers] Follow
Open Access journal
ISSN (Print) 1687-7357 - ISSN (Online) 1687-7365
Published by Hindawi Publishing Corporation [402 journals]
- The Results of MINOS and the Future with MINOS+
Abstract: The MINOS experiment took data from 2005 up until 2012. The MINOS experiment took data from 2005 up until 2012, continuing beyond that as the MINOS+ experiment. The experiment is a two-detector, on-axis, long-baseline experiment, sending neutrinos from Fermilab to the Soudan Underground Laboratory in northern Minnesota. By searching for the deficit of muon neutrinos at the Far Detector, MINOS/MINOS+ is sensitive to the atmospheric neutrino oscillation parameters and . By using the full MINOS data set looking at both disappearance and appearance in both neutrino and antineutrino configurations at the NuMI beam along with atmospheric neutrino data recorded at the FD, MINOS has made the most precise measurement of . Using a full three-flavour framework and searching for appearance, MINOS/MINOS+ gains sensitivity to , the mass hierarchy, and the octant of . Exotic phenomenon is also explored with the MINOS detectors looking for nonstandard interactions and sterile neutrinos. The current MINOS+ era goals are to build on the previous MINOS results improving the precision on the three-flavour oscillation parameter measurements and strengthening the constraints placed on the sterile neutrino parameter space.
PubDate: Sun, 31 Jan 2016 10:11:27 +000
- A -Continuum of Off-Shell Supermultiplets
Abstract: Within each supermultiplet in the standard literature, supersymmetry relates its bosonic and fermionic component fields in a fixed way, particularly to the selected supermultiplet. Herein, we describe supermultiplets wherein a continuously variable “tuning parameter” modifies the supersymmetry transformations, effectively parametrizing a novel “-continuum” of distinct finite-dimensional off-shell supermultiplets, which may be probed already with bilinear Lagrangians that couple to each other and to external magnetic fields, two or more of these continuously many supermultiplets, each “tuned” differently. The dependence on the tuning parameters cannot be removed by any field redefinition, rendering this “-moduli space” observable.
PubDate: Sun, 31 Jan 2016 07:17:40 +000
- Current Status and Future Prospects of the SNO+ Experiment
Abstract: SNO+ is a large liquid scintillator-based experiment located 2 km underground at SNOLAB, Sudbury, Canada. It reuses the Sudbury Neutrino Observatory detector, consisting of a 12 m diameter acrylic vessel which will be filled with about 780 tonnes of ultra-pure liquid scintillator. Designed as a multipurpose neutrino experiment, the primary goal of SNO+ is a search for the neutrinoless double-beta decay (0) of 130Te. In Phase I, the detector will be loaded with 0.3% natural tellurium, corresponding to nearly 800 kg of 130Te, with an expected effective Majorana neutrino mass sensitivity in the region of 55–133 meV, just above the inverted mass hierarchy. Recently, the possibility of deploying up to ten times more natural tellurium has been investigated, which would enable SNO+ to achieve sensitivity deep into the parameter space for the inverted neutrino mass hierarchy in the future. Additionally, SNO+ aims to measure reactor antineutrino oscillations, low energy solar neutrinos, and geoneutrinos, to be sensitive to supernova neutrinos, and to search for exotic physics. A first phase with the detector filled with water will begin soon, with the scintillator phase expected to start after a few months of water data taking. The Phase I is foreseen for 2017.
PubDate: Sun, 24 Jan 2016 10:57:05 +000
- The Effect of Tensor Interaction in Splitting the Energy Levels of
Abstract: We solve approximately Dirac equation for Eckart plus Hulthen potentials with Coulomb-like and Yukawa-like tensor interaction in the presence of spin and pseudospin symmetry for . The formula method is used to obtain the energy eigenvalues and wave functions. We also discuss the energy eigenvalues and the Dirac spinors for Eckart plus Hulthen potentials with formula method. To show the accuracy of the present model, some numerical results are shown in both pseudospin and spin symmetry limits.
PubDate: Thu, 21 Jan 2016 07:03:33 +000
- Neutrino Spin and Dispersion in Magnetized Medium
Abstract: The full energy shift of a massive Dirac neutrino in magnetized electron-positron plasma was investigated using the Matsubara imaginary time and real time formalisms. The neutrino dispersion in the magnetized medium was analyzed as a function of the neutrino spin and mass. It was shown that in a superstrong magnetic field the CP-symmetric plasma contribution to the neutrino energy greatly exceeds the analogous correction in the field-free case. The contribution of plasma to the anomalous magnetic moment of a neutrino was obtained.
PubDate: Tue, 19 Jan 2016 11:01:48 +000
- Stability of a Noncanonical Scalar Field Model during Cosmological Date
Abstract: Using the noncanonical model of scalar field, the cosmological consequences of a pervasive, self-interacting, homogeneous, and rolling scalar field are studied. In this model, the scalar field potential is “nonlinear” and decreases in magnitude with increasing the value of the scalar field. A special solution of the nonlinear field equations of that has time dependency as fixed point is obtained. The fixed point relies on the noncanonical term of action and -parameter; this parameter appeared in energy density of scalar field redshift. By means of such fixed point the different eigenvalues of the equation of motion will be obtained. In different epochs in the evolution of the Universe for different values of and , the potentials as a function of scalar field are attained. The behavior of baryonic perturbations in linear perturbation scenario as a considerable amount of energy density of scalar field at low redshifts prevents the growth of perturbations in the ordinary matter fluid. The energy density in the scalar field is not appreciably perturbed by nonrelativistic gravitational fields, in either the radiation or matter dominant or scalar field dominated epoch.
PubDate: Wed, 13 Jan 2016 09:37:24 +000
- MSSM Dark Matter in Light of Higgs and LUX Results
Abstract: The constraints imposed on the Minimal Supersymmetric Standard Model (MSSM) parameter space by the Large Hadron Collider (LHC) Higgs mass limit and gluino mass lower bound are revisited. We also analyze the thermal relic abundance of lightest neutralino, which is the Lightest Supersymmetric Particle (LSP). We show that the combined LHC and relic abundance constraints rule out most of the MSSM parameter space except a very narrow region with very large (~50). Within this region, we emphasize that the spin-independent scattering cross section of the LSP with a proton is less than the latest Large Underground Xenon (LUX) limit by at least two orders of magnitude. Finally, we argue that nonthermal Dark Matter (DM) scenario may relax the constraints imposed on the MSSM parameter space. Namely, the following regions are obtained: TeV and GeV for low (~10); TeV or TeV and GeV for large (~50).
PubDate: Sun, 10 Jan 2016 12:32:21 +000
- Dark Spinors Hawking Radiation in String Theory Black Holes
Abstract: The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is derived, in the context of dark spinors tunnelling across the horizon. Since a black hole has a well defined temperature, it should radiate in principle all the standard model particles, similar to a black body at that temperature. We investigate the tunnelling of mass dimension one spin-1/2 dark fermions, which are beyond the standard model and are prime candidates to the dark matter. Their interactions with the standard model matter and gauge fields are suppressed by at least one power of unification scale, being restricted just to the Higgs field and to the graviton likewise. The tunnelling method for the emission and absorption of mass dimension one particles across the event horizon of Kerr-Sen axion-dilaton black holes is shown here to provide further evidence for the universality of black hole radiation, further encompassing particles beyond the standard model.
PubDate: Sun, 10 Jan 2016 11:46:33 +000
- Comparing Erlang Distribution and Schwinger Mechanism on Transverse
Momentum Spectra in High Energy Collisions
Abstract: We study the transverse momentum spectra of and mesons by using two methods: the two-component Erlang distribution and the two-component Schwinger mechanism. The results obtained by the two methods are compared and found to be in agreement with the experimental data of proton-proton (), proton-lead (-Pb), and lead-lead (Pb-Pb) collisions measured by the LHCb and ALICE Collaborations at the large hadron collider (LHC). The related parameters such as the mean transverse momentum contributed by each parton in the first (second) component in the two-component Erlang distribution and the string tension between two partons in the first (second) component in the two-component Schwinger mechanism are extracted.
PubDate: Mon, 04 Jan 2016 11:23:57 +000
- The Antineutrino Energy Structure in Reactor Experiments
Abstract: The recent observation of an energy structure in the reactor antineutrino spectrum is reviewed. The reactor experiments Daya Bay, Double Chooz, and RENO have reported a consistent excess of antineutrinos deviating from the flux predictions, with a local significance of about 4 between 4 and 6 MeV of the positron energy spectrum. The possible causes of the structure are analyzed in this work, along with the different experimental approaches developed to identify its origin. Considering the available data and results from the three experiments, the most likely explanation concerns the reactor flux predictions and the associated uncertainties. Therefore, the different current models are described and compared. The possible sources of incompleteness or inaccuracy of such models are discussed, as well as the experimental data required to improve their precision.
PubDate: Thu, 31 Dec 2015 06:54:24 +000
- On the Velocity of Moving Relativistic Unstable Quantum Systems
Abstract: We study properties of moving relativistic quantum unstable systems. We show that in contrast to the properties of classical particles and quantum stable objects the velocity of freely moving relativistic quantum unstable systems cannot be constant in time. We show that this new quantum effect results from the fundamental principles of the quantum theory and physics: it is a consequence of the principle of conservation of energy and of the fact that the mass of the quantum unstable system is not defined. This effect can affect the form of the decay law of moving relativistic quantum unstable systems.
PubDate: Thu, 31 Dec 2015 06:19:55 +000
- Dynamics of Mixed Dark Energy Domination in Teleparallel Gravity and
Abstract: We consider a novel dark energy model to investigate whether it will provide an expanding universe phase. Here we propose a mixed dark energy domination which is constituted by tachyon, quintessence, and phantom scalar fields nonminimally coupled to gravity, in the absence of background dark matter and baryonic matter, in the framework of teleparallel gravity. We perform the phase-space analysis of the model by numerical methods and find the late-time accelerated attractor solutions implying the acceleration phase of universe.
PubDate: Wed, 30 Dec 2015 09:03:59 +000
- Exact Analytical Solution of the -Dimensional Radial Schrödinger
Equation with Pseudoharmonic Potential via Laplace Transform Approach
Abstract: The second-order -dimensional Schrödinger equation with pseudoharmonic potential is reduced to a first-order differential equation by using the Laplace transform approach and exact bound state solutions are obtained using convolution theorem. Some special cases are verified and variations of energy eigenvalues as a function of dimension are furnished. To give an extra depth of this paper, the present approach is also briefly investigated for generalized Morse potential as an example.
PubDate: Wed, 30 Dec 2015 08:50:07 +000
- Criticality of Conformal Anomaly Corrected AdS Black Holes
Abstract: The effects of conformal anomaly on the thermodynamics of black holes are investigated in this paper from the perspective of criticality of AdS black holes. Treating the cosmological constant as thermodynamic pressure, we extend the recent research to the extended phase space. Firstly, we study the - criticality of the uncharged AdS black holes with conformal anomaly and find that conformal anomaly does not influence whether there exists Van der Waals like critical behavior. Secondly, we investigate the - criticality of the charged cases and find that conformal anomaly influences not only the critical physical quantities but also the ratio . The ratio is no longer a constant as before but a function of conformal anomaly parameter . We also show that the conformal parameter should satisfy a certain range to guarantee the existence of critical point that has physical meaning. Our results show the effects of conformal anomaly.
PubDate: Mon, 28 Dec 2015 06:19:25 +000
- Aharonov-Bohm Effect for Bound States on the Confinement of a Relativistic
Scalar Particle to a Coulomb-Type Potential in Kaluza-Klein Theory
Abstract: Based on the Kaluza-Klein theory, we study the Aharonov-Bohm effect for bound states for a relativistic scalar particle subject to a Coulomb-type potential. We introduce this scalar potential as a modification of the mass term of the Klein-Gordon equation, and a magnetic flux through the line element of the Minkowski spacetime in five dimensions. Then, we obtain the relativistic bound states solutions and calculate the persistent currents.
PubDate: Thu, 24 Dec 2015 09:50:24 +000
- Particle Dynamics around Weakly Magnetized Reissner-Nordström Black
Abstract: Considering the geometry of Reissner-Nordström (RN) black hole immersed in magnetic field, we have studied the dynamics of neutral and charged particles. A collision of particles in the inner stable circular orbit is considered and the conditions for the escape of colliding particles from the vicinity of black hole are given. The trajectories of the escaping particle are discussed. Also, the velocity required for this escape is calculated. It is observed that there is more than one stable region if magnetic field is present in the accretion disk of black hole, so the stability of ISCO increases in the presence of magnetic field. Effect of magnetic field on the angular motion of neutral and charged particles is observed graphically.
PubDate: Wed, 16 Dec 2015 14:05:35 +000
- Measurement of Atmospheric Neutrino Oscillations with Very Large Volume
Abstract: Neutrino oscillations have been probed during the last few decades using multiple neutrino sources and experimental set-ups. In the recent years, very large volume neutrino telescopes have started contributing to the field. First ANTARES and then IceCube have relied on large and sparsely instrumented volumes to observe atmospheric neutrinos for combinations of baselines and energies inaccessible to other experiments. Using this advantage, the latest result from IceCube starts approaching the precision of other established technologies and is paving the way for future detectors, such as ORCA and PINGU. These new projects seek to provide better measurements of neutrino oscillation parameters and eventually determine the neutrino mass ordering. The results from running experiments and the potential from proposed projects are discussed in this review, emphasizing the experimental challenges involved in the measurements.
PubDate: Tue, 15 Dec 2015 06:37:44 +000
- The Deep Underground Neutrino Experiment
Abstract: The Deep Underground Neutrino Experiment (DUNE) is a worldwide effort to construct a next-generation long-baseline neutrino experiment based at the Fermi National Accelerator Laboratory. It is a merger of previous efforts and other interested parties to build, operate, and exploit a staged 40 kt liquid argon detector at the Sanford Underground Research Facility 1300 km from Fermilab, and a high precision near detector, exposed to a 1.2 MW, tunable beam produced by the PIP-II upgrade by 2024, evolving to a power of 2.3 MW by 2030. The neutrino oscillation physics goals and the status of the collaboration and project are summarized in this paper.
PubDate: Wed, 09 Dec 2015 09:48:01 +000
- Helical Phase Inflation and Monodromy in Supergravity Theory
Abstract: We study helical phase inflation which realizes “monodromy inflation” in supergravity theory. In the model, inflation is driven by the phase component of a complex field whose potential possesses helicoid structure. We construct phase monodromy based on explicitly breaking global symmetry in the superpotential. By integrating out heavy fields, the phase monodromy from single complex scalar field is realized and the model fulfills natural inflation. The phase-axion alignment is achieved from explicitly symmetry breaking and gives super-Planckian phase decay constant. The -term scalar potential provides strong field stabilization for all the scalars except inflaton, which is protected by the approximate global symmetry. Besides, we show that helical phase inflation can be naturally realized in no-scale supergravity with symmetry since the supergravity setup needed for phase monodromy is automatically provided in the no-scale Kähler potential. We also demonstrate that helical phase inflation can be reduced to another well-known supergravity inflation model with shift symmetry. Helical phase inflation is free from the UV-sensitivity problem although there is super-Planckian field excursion, and it suggests that inflation can be effectively studied based on supersymmetric field theory while a UV-completed framework is not prerequisite.
PubDate: Wed, 09 Dec 2015 06:17:47 +000
- Antineutrino Flux from the Laguna Verde Nuclear Power Plant
Abstract: We present a calculation of the antineutrino flux produced by the reactors at the Laguna Verde Nuclear Power Plant in México, based on the antineutrino spectra produced in the decay chains of the fission fragments of the main isotopes in the reactor core, and their fission rates, which have been calculated using the DRAGON simulation code. We also present an estimate of the number of expected events in a detector made of plastic scintillator with a mass of 1 ton, at 100 m from the reactor cores.
PubDate: Tue, 08 Dec 2015 13:27:28 +000
- Reciprocity and Self-Tuning Relations without Wrapping
Abstract: We consider scalar Wilson operators of = 4 SYM at high spin, , and generic twist in the multicolor limit. We show that the corresponding (non)linear integral equations (originating from the asymptotic Bethe Ansatz equations) respect certain “reciprocity” and functional “self-tuning” relations up to all terms (inclusive) at any fixed ’t Hooft coupling . Of course, this relation entails straightforwardly the well-known (homonymous) relations for the anomalous dimension at the same order in . On this basis we give some evidence that wrapping corrections should enter the nonlinear integral equation and anomalous dimension expansions at the next order , at fixed ’t Hooft coupling, in such a way to reestablish the aforementioned relation (which fails otherwise).
PubDate: Tue, 01 Dec 2015 11:23:58 +000
- On Distributions of Emission Sources and Speed-of-Sound in Proton-Proton
Abstract: The revised (three-source) Landau hydrodynamic model is used in this paper to study the (pseudo)rapidity distributions of charged particles produced in proton-proton and proton-antiproton collisions at high energies. The central source is assumed to contribute with a Gaussian function which covers the rapidity distribution region as wide as possible. The target and projectile sources are assumed to emit isotropically particles in their respective rest frames. The model calculations obtained with a Monte Carlo method are fitted to the experimental data over an energy range from 0.2 to 13 TeV. The values of the squared speed-of-sound parameter in different collisions are then extracted from the width of the rapidity distributions.
PubDate: Mon, 30 Nov 2015 16:42:31 +000
- Bianchi Type-I Universe with Cosmological Constant and Quadratic Equation
of State in Modified Gravity
Abstract: This paper deals with the study of Bianchi type-I universe in the context of gravity. Einstein’s field equations in gravity have been solved in the presence of cosmological constant and quadratic equation of state (EoS) , where is a constant. Here, we have discussed two classes of gravity; that is, and . A set of models has been taken into consideration based on the plausible relation. Also, we have studied some physical and kinematical properties of the models.
PubDate: Thu, 26 Nov 2015 14:00:53 +000
- Non-Hermitian Dirac Hamiltonian in Three-Dimensional Gravity and
Abstract: The Dirac Hamiltonian in the -dimensional curved space-time has been studied with a metric for an expanding de Sitter space-time which is two spheres. The spectrum and the exact solutions of the time dependent non-Hermitian and angle dependent Hamiltonians are obtained in terms of the Jacobi and Romanovski polynomials. Hermitian equivalent of the Hamiltonian obtained from the Dirac equation is discussed in the frame of pseudo-Hermiticity. Furthermore, pseudosupersymmetric quantum mechanical techniques are expanded to a curved Dirac Hamiltonian and a partner curved Dirac Hamiltonian is generated. Using -pseudo-Hermiticity, the intertwining operator connecting the non-Hermitian Hamiltonians to the Hermitian counterparts is found. We have obtained a new metric tensor related to the new Hamiltonian.
PubDate: Thu, 19 Nov 2015 16:00:09 +000
- Critical Combinations of Higher-Order Terms in Einstein-Maxwell Theory and
Abstract: We discuss the role of a particular combination of higher derivative terms in higher dimensional theories, particularly in the background of spontaneous compactification. Two classes of theories are proposed in this paper. The first model as a generalization of the critical gravity with the Maxwell field could have a de Sitter solution. We consider the Lanczos-Lovelock term and Horndeski term as well as the higher-order Maxwell term for the second model, which contains a possible longer expansion time for the inflationary phase. It is interesting that both models can be regarded as the generalization of the Randjbar-Daemi, Salam and Strathdee (RSS) model and give the well behavior for inflation stage under the specific assumptions.
PubDate: Wed, 18 Nov 2015 09:04:26 +000
- Complex-Mass Definition and the Structure of Unstable Particle’s
Abstract: The propagators of unstable particles are considered in framework of the convolution representation. Spectral function is found for a special case when the propagator of scalar unstable particle has Breit-Wigner form. The expressions for the dressed propagators of unstable vector and spinor fields are derived in an analytical way for this case. We obtain the propagators in modified Breit-Wigner forms which correspond to the complex-mass definition.
PubDate: Wed, 18 Nov 2015 08:13:05 +000
- Fate of Electromagnetic Field on the Cracking of PSR J1614-2230 in
Abstract: We study the cracking of compact object PSR J1614-2230 in quadratic regime with electromagnetic field. For this purpose, we develop a general formalism to determine the cracking of charged compact objects. We apply local density perturbations to hydrostatic equilibrium equation as well as physical variables involved in the model. We plot the force distribution function against radius of the star with different parametric values of model both with and without charge. It is found that PSR J1614-2230 remains stable (no cracking) corresponding to different values of parameters when charge is zero, while it exhibits cracking (unstable) when charge is introduced. We conclude that stability region increases as amount of charge increases.
PubDate: Tue, 17 Nov 2015 08:24:13 +000
- Maximally Localized States and Quantum Corrections of Black Hole
Thermodynamics in the Framework of a New Generalized Uncertainty Principle
Abstract: As a generalized uncertainty principle (GUP) leads to the effects of the minimal length of the order of the Planck scale and UV/IR mixing, some significant physical concepts and quantities are modified or corrected correspondingly. On the one hand, we derive the maximally localized states—the physical states displaying the minimal length uncertainty associated with a new GUP proposed in our previous work. On the other hand, in the framework of this new GUP we calculate quantum corrections to the thermodynamic quantities of the Schwardzschild black hole, such as the Hawking temperature, the entropy, and the heat capacity, and give a remnant mass of the black hole at the end of the evaporation process. Moreover, we compare our results with that obtained in the frameworks of several other GUPs. In particular, we observe a significant difference between the situations with and without the consideration of the UV/IR mixing effect in the quantum corrections to the evaporation rate and the decay time. That is, the decay time can greatly be prolonged in the former case, which implies that the quantum correction from the UV/IR mixing effect may give rise to a radical rather than a tiny influence to the Hawking radiation.
PubDate: Tue, 17 Nov 2015 07:54:30 +000
- Augmented Superfield Approach to Nilpotent Symmetries of the Modified
Version of 2D Proca Theory
Abstract: We derive the complete set of off-shell nilpotent and absolutely anticommuting Becchi-Rouet-Stora-Tyutin (BRST), anti-BRST, and (anti-)co-BRST symmetry transformations for all the fields of the modified version of two -dimensional (2D) Proca theory by exploiting the “augmented” superfield formalism where the (dual-)horizontality conditions and (dual-)gauge invariant restrictions are exploited together. We capture the (anti-)BRST and (anti-)co-BRST invariance of the Lagrangian density in the language of superfield approach. We also express the nilpotency and absolute anticommutativity of the (anti-)BRST and (anti-)co-BRST charges within the framework of augmented superfield formalism. This exercise leads to some novel observations which have, hitherto, not been pointed out in the literature within the framework of superfield approach to BRST formalism. For the sake of completeness, we also mention, very briefly, a unique bosonic symmetry, the ghost-scale symmetry, and discrete symmetries of the theory and show that the algebra of conserved charges provides a physical realization of the Hodge algebra (satisfied by the de Rham cohomological operators of differential geometry).
PubDate: Wed, 11 Nov 2015 06:38:20 +000
- Probing Mixing of Photons and Axion-Like Particles by Geometric Phase
Abstract: We find that a geometric phase characterizes the phenomenon of mixing of photons with axion-like particles (ALPs). The laboratory observation of such a phase may provide a novel tool able to detect such a mixing phenomenon. We show that the geometric phase is dependent on the axion-like particle mass and coupling constant. We discuss an interferometric experiment able to detect the geometric phase associated with the ALPs-photon mixing.
PubDate: Tue, 10 Nov 2015 11:44:49 +000