119261053
Renormalization Group Evolution of Neutrino Parameters in Presence of Seesaw Threshold Effects and Majorana Phases
We examine the renormalization group evolution (RGE) for different mixing scenarios in the presence of seesaw threshold effects from high energy scale (GUT) to the low electroweak (EW) scale in the Standard Model (SM) and Minimal Supersymmetric Standard Model (MSSM). We consider four mixing scenarios namely Tri–Bimaximal Mixing, Bimaximal Mixing, Hexagonal Mixing and Golden Ratio Mixing which come from different flavor symmetries at the GUT scale. We find that the Majorana phases play an important role in the RGE running of these mixing patterns along with the seesaw threshold corrections. We present a comparative study of the RGE of all these mixing scenarios both with and without Majorana CP phases when seesaw threshold corrections are taken into consideration. We find that in the absence of these Majorana phases both the RGE running and seesaw effects may lead to θ13<5° at low energies both in the SM and MSSM. However, if the Majorana phases are incorporated into the mixing matrix the running can be enhanced both in the SM and MSSM. Even by incorporating non-zero Majorana CP phases in the SM, we do not get θ13 in its present 3σ range. The current values of the two mass squared differences and mixing angles including θ13 can be produced in the MSSM case with tan⁡β=10 and non-zero Majorana CP phases at low energy. We also calculate the order of effective Majorana mass and Jarlskog Invariant for each scenario under consideration.
118483048
TRIBIMAXIMAL MIXING IN NEUTRINO MASS MATRICES WITH TEXTURE ZEROS OR VANISHING MINORS
We study the existence of one/two texture zeros or one/two vanishing minors in the neutrino mass matrix with μτ symmetry. In the basis where the charged lepton mass matrix and the Dirac neutrino mass matrix are diagonal, the one/two zeros or one/two vanishing minors on the right-handed Majorana mass matrix having μτ symmetry will propagate via seesaw mechanism as one/two vanishing minors or one/two texture zeros in the neutrino mass matrix with μτ symmetry respectively. It is found that only five such texture structures of the neutrino mass matrix are phenomenologically viable. For tribimaximal mixing, these texture structures reduce the number of free parameters to one. Interesting predictions are obtained for the effective Majorana mass Mee, the absolute mass scale and the Majorana-type CP violating phases.
2063566
Phenomenology of Two-Texture Zero Neutrino Mass Matrices
The generic predictions of two-texture zero neutrino mass matrices in the flavor basis have been examined especially in relation to the degeneracies between mass matrices within a class and interesting constraints on the neutrino parameters have been obtained. It is shown that the knowledge of the octant of ${\ensuremath{\theta}}_{23}$, the sign of $\mathrm{cos}﻿\ensuremath{\delta}$, and neutrino mass hierarchy can be used to lift these degeneracies.
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.
119300069
Parallel hybrid textures of lepton mass matrices
We analyse the parallel hybrid texture structures in the charged lepton and the neutrino sector. These parallel hybrid texture structures have physical implications as they cannot be obtained from arbitrary lepton mass matrices through weak basis transformations. The total sixty parallel hybrid texture structures can be grouped into twelve classes, and all the hybrid textures in the same class have identical physical implications. We examine all the twelve classes under the assumption of non-factorizable phases in the neutrino mass matrix. Five out of the total twelve classes are found to be phenomenologically disallowed. We study the phenomenological implications of the allowed classes for 1-3 mixing angle, Majorana and Dirac-type CP violating phases. Interesting constraints on effective Majorana mass are obtained for all the allowed classes.
119206892
Strange freezeout
We argue that known systematics of hadron cross sections may cause different particles to freeze out of the fireball produced in heavy-ion collisions at different times. We find that a simple model with two freezeout points is a better description of data than that with a single freezeout, while still remaining predictive. The resulting fits seem to present constraints on the late stage evolution of the fireball, including the tantalizing possibility that the QCD chiral transition influences the yields at √
55918485
Phase transition in QCD with broken SU(2) flavor symmetry
We report the first investigation of the QCD transition temperature T c for two flavors of staggered quarks with unequal masses at lattice spacings of ¼T. On changing the u/d quark mass ratio in such a way that m 2 π0 /m 2 π±> changes from 1 to 0.78, thus bracketing the physical value of this ratio, we find that T c remains unchanged in units of both m ρ and Λ MS - .
121860723
Possibility of structure in projectile fragmentation in high energy heavy ion reactions
Abstract We show that a quantum mechanical analogue of the Goldhaber model predicts a structure in the momentum distribution of α's fragmenting from the projectile 6 Li. This structure should be measurable.
67811342
GRAPES-3¿A high-density air shower array for studies on the structure in the cosmic-ray energy spectrum near the knee
Abstract The change in the spectral index from about - 2.7 to - 3.1 at ∼ 3 × 10 15  eV in the all-particle energy spectrum of primary cosmic rays is very significant for learning about the nature of cosmic sources of ultra-high energy particles and their acceleration and propagation in the galactic disk. Any observation of a fine structure in the spectrum would be important for improving our understanding of these physical processes. The GRAPES-3 air shower array has been designed to achieve higher precision in determination of various shower parameters to enable observation of any fine structure in the energy spectrum, if it exists. The details of the shower detectors, shower trigger and the data acquisition system are presented here along with estimates of trigger efficiencies from Monte Carlo simulations for primary photons ( γ -rays) and several nuclei.
118646248
Predictions from High Scale Mixing Unification Hypothesis
We investigate the renormalization group evolution of masses and mixing angles of Majorana neutrinos under the ``high scale mixing unification'' hypothesis. Assuming the unification of quark-lepton mixing angles at a high scale, we show that all the experimentally observed neutrino oscillation parameters can be obtained, within the $3\text{\ensuremath{-}}\ensuremath{\sigma}$ range, through the running of corresponding renormalization group equations provided neutrinos have the same charge parity and are quasidegenerate. One of the novel results of our analysis is that ${\ensuremath{\theta}}_{23}$ turns out to be nonmaximal and lies in the second octant. Furthermore, we derive new constraints on the allowed parameter space for the unification scale, supersymmetry breaking scale and $\mathrm{tan}\ensuremath{\beta}$, for which the high scale mixing unification hypothesis works.