10127072
Phenomenological Analysis of Hybrid Textures of Neutrinos
Abstract We present a comprehensive phenomenological analysis of the allowed hybrid textures of neutrinos. Out of a total of sixty hybrid textures with one equality between the elements of neutrino mass matrix and one texture zero only twenty three are found to be viable at 99% C.L. whereas the earlier analysis found fifty four to be viable. We examine the phenomenological implications of the allowed hybrid textures including Majorana type CP-violating phases, 1–3 mixing angle and Dirac type CP-violating phase, δ. We, also, obtain lower bound on effective Majorana mass for all the allowed hybrid textures.
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.
118520803
Corrections for tribimaximal, bimaximal and democratic neutrino mixing matrices
A bstractIn this work we analyze the corrections to tribimaximal (TBM), bimaximal (BM) and democratic (DC) mixing matrices for explaining large reactor mixing angle θ13 and checking the consistency with other neutrino mixing angles. The corrections are parameterized in terms of small orthogonal rotations (R) with corresponding modified PMNS matrix of the form Rij·U·Rkl where Rij is rotation in ij sector and U is any one of these special matrices. We showed the rotations R13·U·R23, R12·U·R13 for BM and R13·U·R13 for TBM perturbative case successfully fit all neutrino mixing angles within 1σ range. The perturbed PMNS matrix R12·U·R13 for DC, TBM and R23·U·R23 for TBM case is successful in producing mixing angles at 2σ level. The other rotation schemes are either excluded or successful in producing mixing angles at 3σ level.
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.
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.
119252719
Near maximal atmospheric mixing in neutrino mass matrices with two vanishing minors
Abstract In the flavor basis there are seven cases of two vanishing minors in the neutrino mass matrix which can accommodate the present neutrino oscillation data including the recent T2K data. It is found that two of these cases, namely B 5 and B 6 predict near maximal atmospheric neutrino mixing in the limit of large effective neutrino mass. This feature remains irrespective of the values of solar and reactor mixing angles. A non-zero reactor mixing angle is naturally accommodated in these textures.
118904356
Multiplicity distributions of intermediate mass fragments in the thermodynamic model
Multiplicity distributions of intermediate mass fragments (IMFs) seen in intermediate energy heavy ion collisions have been of great interest in the last ten years. The distributions of single intermediate sized elements are close to Poissonian and have been subjected to widely different physical interpretations. We calculate the multiplicity distributions in a thermodynamic model whose physical basis is equal populations in phase space, which implies equilibrium statistics. We found distributions of a single element are to a good approximation Poissonian, and this result is attributed to the small emission probability of a given IMF among all the possible channels. We also found significant deviation from a Poisson distribution for a range of IMFs, and suggest strong correlations as an explanation. The systematics of the multiplicity distributions are explored in both one-component and two-component models. In the one-component model, sudden changes for the multiplicity distributions are found at the phase transition region. In the two-component model, the multiplicity distributions have more subtleties. Results from the current model are compared with available data, and good agreements are found. New signals for the multiparticle correlations are also suggested.
14927510
A Transport Model for Nuclear Reactions Induced by Radioactive Beams
Major ingredients of an isospin and momentum dependent transport model for nuclear reactions induced by radioactive beams are outlined. Within the IBUU04 version of this model we study several experimental probes of the equation of state of neutron‐rich matter, especially the density dependence of the nuclear symmetry energy. Comparing with the recent experimental data from NSCL/MSU on isospin diffusion, we found a nuclear symmetry energy of Esym(ρ) ≈ 31.6(ρ/ρ0)1.05 at subnormal densities. Predictions on several observables sensitive to the density dependence of the symmetry energy at supranormal densities accessible at GSI and the planned Rare Isotope Accelerator (RIA) are also made.
119297909
High Scale Mixing Unification for Dirac Neutrinos
Starting with high scale mixing unification hypothesis, we investigate the renormalization group evolution of mixing parameters and masses for Dirac type neutrinos. Following this hypothesis, the PMNS mixing angles and phase are taken to be identical to the CKM ones at a unifying high scale. Then, they are evolved to a low scale using renormalization-group equations. The notable feature of this hypothesis is that renormalization group evolution with quasi-degenerate mass pattern can explain largeness of leptonic mixing angles even for Dirac neutrinos. The renormalization group evolution "naturally" results in a non-zero and small value of leptonic mixing angle $\theta_{13}$. One of the important predictions of this work is that the mixing angle $\theta_{23}$ is non-maximal and lies only in the second octant. We also derive constraints on the allowed parameter range for the SUSY breaking and unification scales for which this hypothesis works. The results are novel and can be tested by present and future experiments.
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 - .
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.