35648525
2540 km: bimagic baseline for neutrino oscillation parameters.
We show that a source-to-detector distance of 2540 km, motivated recently [S. K. Raut, R. S. Singh, and S. U. Sankar, arXiv:0908.3741] for a narrow band superbeam, offers multiple advantages for a low energy neutrino factory with a detector that can identify muon charge. At this baseline, for any neutrino hierarchy, the wrong-sign muon signal is almost independent of CP violation and θ(13) in certain energy ranges. This allows the identification of the hierarchy in a clean way. In addition, part of the muon spectrum is also sensitive to the CP violating phase and θ(13), so that the same setup can be used to probe these parameters as well.
119869500
Lower bounds on the smallest lepton mixing angle
We give minimal values for the smallest lepton mixing parameter |U{sub e3}|, applying 2-loop renormalization group equations in an effective theory approach. This is relevant in scenarios that predict an inverted neutrino mass spectrum with the smallest mass and |U{sub e3}| being zero at tree level, a situation known to be preserved at 1-loop order. At 2-loop, |U{sub e3}| is generated at a level of 10{sup -12}-10{sup -14}. Such small values are of interest in supernova physics. Corresponding limits for the normal mass ordering are several orders of magnitude larger. Our results show that |U{sub e3}| can in general be expected to be nonzero.
118649508
Renormalization group evolution of neutrino masses and mixing in seesaw models: A Review
We consider different extensions of the standard model which can give rise to the small active neutrino masses through seesaw mechanisms, and their mixing. These tiny neutrino masses are generated at some high energy scale by the heavy seesaw fields which then get sequentially decoupled to give an effective dimension-5 operator. The renormalization group evolution of the masses and the mixing parameters of the three active neutrinos in the high energy as well as the low energy effective theory is reviewed in this article.
118650147
Minimal Lepton Flavor Violation and renormalization group evolution of lepton masses and mixing
We study the renormalization group equations (RGEs) of the neutrino parameters in models of Minimal Lepton Flavor Violation. In such models, the RGEs can be described in terms of flavor spurions, such that only the coefficients depend on the specific model. We explicitly demonstrate this method for the SM and MSSM for both Type-I and Type-III seesaw models. For that purpose, the RGEs of neutrino parameters in the MSSM Type-III seesaw have been computed. We have extended this method to get the evolution equations at second order. The implications for leptogenesis are also discussed.
119875035
New physics signals at long baseline experiments
We develop a formalism that gives analytically tractable expressions for flavor conversion probabilities at long baseline experiments, in the presence of any number of sterile neutrino species or with CPT violation. Using a perturbative expansion in the small parameters we show that, even in a completely general analysis, only certain specific combinations of the mixing parameters are relevant and hence can be probed in the experiments. We identify the long baseline experiments which will be able to probe those observable combinations in a clean manner and estimate their reach in measuring or constraining those observables.
199675394
2540 km: Bimagic baseline for neutrino oscillation parameters
We consider a low energy neutrino factory setup with a detector placed at a distance of 2540 km. At this baseline, for both normal and inverted hierarchical neutrino mass spectrum, the wrong‐sign muon event spectrum is almost independent of CP phase δ and the mixing angle θ13 in a specific energy window. This leads to an unambiguous determination of the hierarchy. In addition, a part of the muon spectrum remain sensitive to δ and θ13, so that the same setup can be used to probe these parameters as well using a broadband beam.
119438703
CHARGED POLYTROPIC STARS AND A GENERALIZATION OF LANE–EMDEN EQUATION
In this paper we discuss charged stars with polytropic equation of state, where we derive an equation analogous to the Lane–Endem equation. We assume that these stars are spherically symmetric, and the electric field have only the radial component. First we review the field equations for such stars and then we proceed with the analog of the Lane–Emden equation for a polytropic Newtonian fluid and their relativistic equivalent (Tooper, 1964).1 These kind of equations are very interesting because they transform all the structure equations of the stars in a group of differential equations which are much more simple to solve than the source equations. These equations can be solved numerically for some boundary conditions and for some initial parameters. For this we assume that the pressure caused by the electric field obeys a polytropic equation of state too.
118648288
Universe in the inflationary phase: Revisited
The inflationary phase of the Universe is explored by proposing a toy model related to the scalar field, termed as `inflaton'. The potential part of the energy density in the said era is assumed to have a constant vacuum energy density part and a variable part containing the inflaton. The prime idea of the proposed model constructed in the framework of the closed universe is based on a fact that the inflaton is the root cause of the orientation of the space. According to this model the expansion of the Universe in the inflationary epoch is not approximately rather exactly exponential in nature and thus it can solve some of the fundamental puzzles, viz. flatness and horizon problems. The model keeps room for the end of inflationary era.
118535855
Singularity-free dark energy star
We propose a model for an anisotropic dark energy star where we assume that the radial pressure exerted on the system due to the presence of dark energy is proportional to the isotropic perfect fluid matter density. We discuss various physical features of our model and show that the model satisfies all the regularity conditions and is stable as well as singularity-free.
18892938
Electromagnetic mass model admitting conformal motion
We study charged fluid spheres under the 4-dimensional Einstein-Maxwell space-time. The solutions thus obtained admitting conformal motion. We also investigate whether the solutions set provide electromagnetic mass models such that the physical parameters including the gravitational mass arise from the electromagnetic field alone. In this connection three cases are studied here in detail with the propositions: (1) $p = - \rho$, (2) $\sigma e^{\lambda/2} = \sigma_0$ and (3) $8 \pi p - E^2 = p_0$ where $\rho$, $p$, $\sigma$ are respectively the usual matter density, fluid pressure and charge density of the spherical distribution. Based on these assumptions several features are explored which seems physically very interesting.
582356
SCENARIOS OF COSMIC STRING WITH A VARIABLE COSMOLOGICAL CONSTANT
Exact solutions to the Einstein field equations with cosmic string and a space-varying cosmological constant, viz. Λ = Λ(r), in the energy–momentum tensors are presented. Three cases have been studied: the variable cosmological constant (1) has power law dependence, (2) is proportional to the string fluid density, and (3) is purely a constant. Some cases of interesting physical consequences have been found where (i) the variable cosmological constant can be represented by a power law of the type Λ = 3r-2, (ii) the variable cosmological constant and the cosmic string density are interdependent according to the relation Λ = -8πρs, and (iii) the cosmic string density can be scaled by a power law of the type ρs = r-2. It is also shown that several known solutions can be recovered from the general form of the solutions obtained here.