120578159
Exact solutions of the field equations for Charap’s chiral invariant model of the pion dynamics
The field equations for the chiral invariant model of pion dynamics developed by Charap have been revisited. Two new types of solutions of these equations have been obtained. Each type allows infinite number of solutions. It has also been shown that the chiral invariant field equations admit invariance for a transformation of the dependent variables.
13171620
Role of modified Chaplygin gas in accelerated universe
In this paper, we have considered a model of modified Chaplygin gas and its role in the accelerating phase of the universe. We have assumed that the equation of state of this modified model is valid from the radiation era to the ΛCDM model. We have used recently developed statefinder parameters in characterizing different phases of the universe diagrammatically.
119261702
Emergent universe in brane world scenario with Schwarzschild–de Sitter bulk
A model of an emergent universe is obtained in brane world. Here the bulk energy is in the form of cosmological constant, while the brane consists of a fluid satisfying an equation of state of the form $${p_{b}=\frac{1}{3}\rho_{b}}$$ , which is effectively a radiation equation of state at high energies. It is shown that with the positive bulk cosmological constant, one of our models represents an emergent universe.
118537252
Generalized Bekenstein–Hawking system: logarithmic correction
The present work is a generalization of the recent work [arXiv.1206.1420] on the modified Hawking temperature on the event horizon. Here the Hawking temperature is generalized by multiplying the modified Hawking temperature by a variable parameter $$\alpha $$α representing the ratio of the growth rate of the apparent horizon to that of event horizon. It is found that both the first and the generalized second law of thermodynamics are valid on the event horizon for any fluid distribution. Subsequently, the Bekenstein entropy is modified on the event horizon and the thermodynamical laws are examined. Finally, an interpretation of the parameters involved is presented.
117551329
Inflationary Solutions for Higher Dimensional Anisotropic Cosmological Model in Scalar-Tensor Theory II
This is the second paper of the series where we have considered Brans-Dicke (B-D) theory as well as general scalar tensor theory of gravitation in higher dimensional space-time model in the false vacuum state. We have examined whether inflationary solutions are possible both for constant or variable coupling parameter ω. Also the nature of the scalar field and the coupling parameter are discussed in the asymptotic limit.
120564431
MOTION OF TEST PARTICLES AROUND GAUGE MONOPOLES OR NEAR COSMIC STRINGS CONSIDERING SEMICLASSICAL GRAVITATIONAL EFFECTS
In this paper, we have studied the motion of test particles near cosmic strings as well as around gauge monopoles with semiclassical gravitational effects. In case of cosmic strings, the nature of the trajectory of the test particle has changed due to the semiclassical effects while for gauge monopole the trajectory has no effect due to the semiclassical consideration.
53354264
The mass-hierarchy and CP-violation discovery reach of the LBNO long-baseline neutrino experiment
A bstractThe next generation neutrino observatory proposed by the LBNO collaboration will address fundamental questions in particle and astroparticle physics. The experiment consists of a far detector, in its first stage a 20 kt LAr double phase TPC and a magnetised iron calorimeter, situated at 2300 km from CERN and a near detector based on a highpressure argon gas TPC. The long baseline provides a unique opportunity to study neutrino flavour oscillations over their 1st and 2nd oscillation maxima exploring the L/E behaviour, and distinguishing effects arising from δCP and matter.In this paper we have reevaluated the physics potential of this setup for determining the mass hierarchy (MH) and discovering CP-violation (CPV), using a conventional neutrino beam from the CERN SPS with a power of 750 kW. We use conservative assumptions on the knowledge of oscillation parameter priors and systematic uncertainties. The impact of each systematic error and the precision of oscillation prior is shown. We demonstrate that the first stage of LBNO can determine unambiguously the MH to > 5σ C.L. over the whole phase space. We show that the statistical treatment of the experiment is of very high importance, resulting in the conclusion that LBNO has ~ 100% probability to determine the MH in at most 4-5 years of running. Since the knowledge of MH is indispensable to extract δCP from the data, the first LBNO phase can convincingly give evidence for CPV on the 3σ C.L. using today’s knowledge on oscillation parameters and realistic assumptions on the systematic uncertainties.
118521330
Stringent constraint on neutrino Lorentz-invariance violation from the two IceCube PeV neutrinos
LAPTh, Univ. de Savoie, CNRS, B.P.110, Annecy-le-Vieux F-74941, FranceIt has been speculated that Lorentz-invariance violation (LIV) might be generated by quantum-gravity (QG) eﬀects. As a consequence, particles may not travel at the universal speed of light. Inparticular, superluminal extragalactic neutrinos would rapidly lose energy via the bremssthralung ofelectron-positron pairs (ν → ν e
118411783
Brownian motion in strongly coupled, anisotropic Yang-Mills plasma: A holographic approach
We employ methods of gauge/string duality to analyze the Brownian motion and the concomitant Langevin equation of a heavy quark in a strongly coupled, thermal, anisotropic Yang-Mills plasma. We consider fluctuations both along and perpendicular to the direction of anisotropy and study the effects of anisotropy on the drag coefficient, the diffusion constant and the Langevin coefficient for both the directions. We also verify the fluctuation-dissipation theorem for Brownian motion in an anisotropic medium.
53554327
7 keV sterile neutrino dark matter in U(1)R-lepton number model
A bstractWe study the phenomenology of a keV sterile neutrino in a supersymmetric model with U(1)R-lepton number in the light of a very recent observation of an X-ray line signal at around 3.5 keV, detected in the X-ray spectra of Andromeda galaxy and various galaxy clusters including the Perseus galaxy cluster. This model not only provides a small tree level mass to one of the active neutrinos but also renders a suitable warm dark matter candidate in the form of a sterile neutrino with negligible active-sterile mixing. Light neutrino masses and mixing can be explained once one-loop radiative corrections are taken into account. The scalar sector of this model can accommodate a Higgs boson with a mass of ∼125 GeV. In this model gravitino is the lightest supersymmetric particle (LSP) and we also study the cosmological implications of this light gravitino with mass ∼OGeV$$ \sim \mathcal{O}\left(\mathrm{GeV}\right) $$.
118538860
Wess-Zumino-Witten Model for Galilean Conformal Algebra
In this note, we construct a Wess–Zumino–Witten model based on the Galilean conformal algebra in two-spacetime dimensions, which is a nonrelativistic analogue of the relativistic conformal algebra. We obtain exact background corresponding to σ-models in six dimensions (the dimension of the group manifold) and a central charge c = 6. We carry out a Sugawara type construction to verify the conformal invariance of the model. Further, we discuss the feasibility of the background obtained as a physical spacetime metric.