16189897
PHENOMENOLOGICAL IMPLICATIONS OF A CLASS OF LEPTON MASS MATRICES
Phenomenological implications of a class of lepton mass matrices with parallel texture structure have been examined and phenomenologically interesting constraints on charged lepton and neutrino mass matrix parameters have been obtained.
119117378
Hadron energy response of the Iron Calorimeter detector at the India-based Neutrino Observatory
The results of a Monte Carlo simulation study of the hadron energy response for the magnetized Iron CALorimeter detector, ICAL, proposed to be located at the India-based Neutrino Observatory (INO) is presented. Using a GEANT4 modeling of the detector ICAL, interactions of atmospheric neutrinos with target nuclei are simulated. The detector response to hadrons propagating through it is investigated using the hadron hit multiplicity in the active detector elements. The detector response to charged pions of fixed energy is studied first, followed by the average response to the hadrons produced in atmospheric neutrino interactions using events simulated with the NUANCE event generator. The shape of the hit distribution is observed to fit the Vavilov distribution, which reduces to a Gaussian at high energies. In terms of the parameters of this distribution, we present the hadron energy resolution as a function of hadron energy, and the calibration of hadron energy as a function of the hit multiplicity. The energy resolution for hadrons is found to be in the range 85% (for 1 GeV) – 36% (for 15 GeV).
16931053
CP-odd weak basis invariants and texture zeros
We construct the CP-odd weak basis invariants from the neutrino mass matrix in a weak basis, in which the charged lepton mass matrix is diagonal, and find the necessary and sufficient conditions for CP conservation. We study the interrelationships between different CP-odd weak basis invariants to examine their implications for the Dirac- and Majorana-type CP violating phases for the phenomenologically allowed Frampton-Glashow-Marfatia texture zero structures of the neutrino mass matrix.
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 .
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.
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.
118619694
On nuclear stopping in asymmetric colliding nuclei
Abstract Using the isospin-dependent quantum molecular dynamics (IQMD) model, nuclear stopping is analyzed in asymmetric colliding channels by keeping the total reacting mass fixed. The calculations have been performed by varying the mass asymmetry of the colliding pairs with different neutron–proton ratios at an incident beam energy of 250 MeV/nucleon. We find sizable effects of mass asymmetry on nuclear stopping and on the equilibrium of the nuclear matter. A reasonable agreement is also observed between the experimental data and our present calculations.
118577769
Effect of density dependent symmetry energy on Elliptical flow
Nuclear Physics in general and heavy-ion collisions in particular is of central interest in investigating the matter under the extreme conditions of temperature and compression. Among the different observables, collective flow and its various forms enjoys a special status, due to its sensitivity towards model ingredients that define equation of state. The elliptical flow, which is the squeeze out of spectator matter out of the reaction plane, is more suited to study the collective flow,, as compared to the directed flow, which is constrained only along the reaction plane.
117717582
The Bottom of the Main Sequence and Beyond: Speculations, Calculations, Observations, and Discoveries (1958-2002)
In this paper, I briefly review the theoretical and observational work done since 1958 on the gaseous objects with mass below the H-burning limit. Special attention is paid to the theory that I developed during the period 1958-1962 for the hydrogen-rich gaseous objects with mass below the minimum main sequence mass of ~ 0.08 Msun. The three main predictions of this theory (Kumar 1962a; Kumar 1962b; Kumar 1963a; Kumar 1963b) are discussed. Fragmentation processes for interstellar clouds are discussed, and it is pointed out that the minimum mass of a gaseous fragment may be as low as 0.001 Msun. Observational results obtained since 1995 on the luminous and dark objects of very low mass are briefly reviewed. Comments are made on the basic nature of the stars and planets, and it is pointed out that processes of star formation are fundamentally different from those of planet formation. Arguments are presented to show that some of the very-low-mass dark companions, discovered since 1995, were most probably formed by the star formation processes and not by the planet formation processes.
119227233
Phase space analysis of fragmentation and the role of mass asymmetry
Based on the quantum molecular dynamics picture, we aim to understand heavy-ion collisions in terms of participant spectator matter leading to various fragments of different sizes. The study is performed for symmetric as well as asymmetric reactions at E = 200 MeV nucleon−1 for central collisions. Our results highlight the importance of a phase space analysis of the fragment distribution in symmetric and asymmetric collisions in terms of light mass fragments that are a component of participant matter and intermediate mass fragments, which come from the spectator region.
123091744
Supercurrent Anomaly in the Framework of Analytic Regularization