15773149
CONSTRAINTS ON THE NEUTRINO PARAMETERS FROM THE "RISE-UP" IN THE BORON NEUTRINO SPECTRUM AT LOW ENERGIES
The rise-up in boron neutrino spectrum at low energies has been studied within the framework of "pure LMA" scenario. Indirect bounds on the spectral "upturn" have been obtained from the available solar neutrino data. These bounds have been used to demonstrate the efficacy of the precision measurements of the "upturn" for further constraining the neutrino parameter space allowed by SNO salt phase data. The sterile neutrino flux has been constrained in the light of the recent 766.3 Ty KamLAND spectral data.
9876938
Neutrino Parameter Space for a Vanishing ee Element in the Neutrino Mass Matrix
The consequences of a texture zero at the ee entry of neutrino mass matrix in the flavor basis, which also implies a vanishing effective Majorana mass for neutrinoless double beta decay, have been studied for Majorana neutrinos. The neutrino parameter space under this condition has been constrained in the light of all available neutrino data including the CHOOZ bound on .
117945191
Degeneracies of Neutrino Mass Matrices with two Texture Zeros
We examine the phenomenological implications of the neutrino mass matrices with two texture zeros, especially, in relation to their degeneracies.
119100875
Symmetry based parametrizations of the lepton mixing matrix
There are many mixing schemes based upon flavor symmetries that predict a vanishing $\theta_{13}$. These mixing schemes need corrections or modifications to account for recent experimental measurements of non-zero $\theta_{13}$. We propose new parameterizations for the lepton mixing matrix to quantify the minimal modifications needed in these mixing schemes. The parameterizations can be factorized in two parts: $U_{0}(a,b)$ and $R(\theta,\phi)$. The first factor can be viewed as a zeroth order mixing matrix coming from some flavor symmetry. It reproduces the popular mixing schemes based upon flavor symmetries for suitable values of $a$ and $b$. The second factor can be interpreted as a minimal modification to the mixing matrix and is responsible for non zero $\theta_{13}$, non-maximal $\theta_{23}$ and CP violation. We also find the experimentally allowed parameter space for the parameters $a$ and $b$ and compare it with the symmetry based values for these parameters.
15951627
Texture 4 zero Fritzsch-like lepton mass matrices
For Majorana or Dirac neutrinos, using Fritzsch-like texture 4 zero mass matrices with parallel texture structures for the charged leptons and the Dirac neutrino mass matrix (${M}_{\ensuremath{\nu}D}$), detailed predictions for cases pertaining to normal/inverted hierarchy as well as degenerate scenarios of neutrino masses have been carried out. The inverted hierarchy as well as degenerate scenarios seem to be ruled out at $3\ensuremath{\sigma}$ C.L. for both Majorana and Dirac neutrinos. For normal hierarchy, Jarlskog's rephasing invariant parameter $J$, the $CP$ violating Dirac-like phase $\ensuremath{\delta}$, and the effective neutrino mass $⟨{m}_{ee}⟩$ have been calculated. For this case, lower limits of ${m}_{{\ensuremath{\nu}}_{1}}$ and ${\ensuremath{\theta}}_{13}$ would have implications for the nature of neutrinos.
119298119
Unitarity constraints on trimaximal mixing
When the neutrino mass eigenstate {nu}{sub 2} is trimaximally mixed, the mixing matrix is called trimaximal. The middle column of the trimaximal mixing matrix is identical to tribimaximal mixing and the other two columns are subject to unitarity constraints. This corresponds to a mixing matrix with four independent parameters in the most general case. Apart from the two Majorana phases, the mixing matrix has only one free parameter in the CP conserving limit. Trimaximality results in interesting interplay between mixing angles and CP violation. A notion of maximal CP violation naturally emerges here: CP violation is maximal for maximal 2-3 mixing. Similarly, there is a natural constraint on the deviation from maximal 2-3 mixing which takes its maximal value in the CP conserving limit.
15505916
Exact Superpotentials from Matrix Models
Dijkgraaf and Vafa (DV) have conjectured that the exact superpotential for a large class of = 1 SUSY gauge theories can be extracted from the planar limit of a certain holomorphic matrix integral. We test their proposal against existing knowledge for a family of deformations of = 4 SUSY Yang-Mills theory involving an arbitrary polynomial superpotential for one of the three adjoint chiral superfields. Specifically, we compare the DV prediction for these models with earlier results based on the connection between SUSY gauge theories and integrable systems. We find complete agreement between the two approaches. In particular we show how the DV proposal allows the extraction of the exact eigenvalues of the adjoint scalar in the confining vacuum and hence computes all related condensates of the finite-N gauge theory. We extend these results to include Leigh-Strassler deformations of the = 4 theory.
122510459
Exact Bianchi Type-I Cosmological Models in a Scalar-Tensor Theory
Abstract
In this paper, a spatially homogeneous and anisotropic Bianchi type-I space-time filled with perfect fluid is investigated within the framework of a scalar-tensor theory proposed by Saez and Ballester. Two different physically viable models of the universe are obtained by using a special law of variation for Hubble’s parameter that yields a constant value of deceleration parameter. One of the models is found to generalize a model recently investigated by Reddy et al. (Astrophys. Space Sci. 306:171, 2006). The Einstein’s field equations are solved exactly and the solutions are found to be consistent with the recent observations of type Ia supernovae. A detailed study of physical and kinematical properties of the models is carried out.

118862615
Systematic Study on System Size Dependence of Global Stopping: Role of Momentum-Dependent Interactions and Symmetry Energy
Using the isospin-dependent quantum molecular dynamical (IQMD) model, we systematically study the role of momentum dependent interactions in global stopping and analyze the effect of symmetry energy in the presence of momentum dependent interactions. For this, we simulate the reactions by varying the total mass of the system from 80 to 394 at different beam energies from 30 to 1000 MeV/nucleon over central and semi-central geometries. The study is carried in the presence of momentum dependent interactions and symmetry energy by taking into account hard equation of state. The nuclear stopping is found to be sensitive towards the momentum dependent interactions and symmetry energy at low incident energies. The momentum dependent interactions are found to weaken the finite size effects in nuclear stopping.
117887312
Influence of momentum dependent interactions on nuclear stopping in symmetric heavy-ion collisions
The role of momentum dependent interactions is studied in nuclear stopping at intermediate energy using an isospin-dependent quantum molecular dynamics model. Present calculations are performed at incident energy between 50 and 1000 MeV/nucleon. Our findings show that nuclear stopping is sensitive towards the impact parameter, incident energies as well as towards the mass of the colliding system. Further, the degree of stopping is suppressed by the inclusion of momentum dependent interactions, whereas the particle production is not affected by the MDI.
119276827
Observational constraints on Hubble constant and deceleration parameter in power-law cosmology
In this paper, we show that the expansion history of the Universe in power-law cosmology essentially depends on two crucial parameters, namely the Hubble constant $H_{0}$ and deceleration parameter $q$. We find the constraints on these parameters from the latest $H(z)$ and SNe Ia data. At 1$\sigma$ level the constraints from $H(z)$ data are obtained as $q=-0.18_{-0.12}^{+0.12}$ and $H_{0}=68.43_{-2.80}^{+2.84}$ km s$^{-1}$ Mpc$^{-1}$ while the constraints from the SNe Ia data read as $q=-0.38_{-0.05}^{+0.05}$ and $H_{0}=69.18_{-0.54}^{+0.55}$ km s$^{-1}$ Mpc$^{-1}$. We also perform the joint test using $H(z)$ and SNe Ia data, which yields the constraints $q=-0.34_{-0.05}^{+0.05}$ and $H_{0}=68.93_{-0.52}^{+0.53}$ km s$^{-1}$ Mpc$^{-1}$. The estimates of $H_{0}$ are found to be in close agreement with some recent probes carried out in the literature. The analysis reveals that the observational data successfully describe the cosmic acceleration within the framework of power-law cosmology. We find that the power-law cosmology accommodates well the $H(z)$ and SNe Ia data. We also test the power-law cosmology using the primordial nucleosynthesis, which yields the constraints $q\gtrsim 0.72$ and $H_{0}\lesssim 41.49$ km s$^{-1}$ Mpc$^{-1}$. These constraints are found to be inconsistent with the ones derived from the $H(z)$ and SNe Ia data. We carry out the statefinder analysis, and find that the power-law cosmological models approach the standard $\Lambda$CDM model as $q\rightarrow -1$. Finally, we conclude that despite having several good features power-law cosmology is not a complete package for the cosmological purposes.