Investigating the sterile neutrino parameters with QLC in 3 + 1 scenario

In the scenario with four generation quarks and leptons and using a 3 + 1 neutrino model having one sterile and the three standard active neutrinos with a $4 \times 4$ unitary transformation matrix, $U_{PMNS_{4}}$, we perform a model-based analysis using the latest global data and determine bounds on the sterile neutrino parameters i.e. the neutrino mixing angles. Motivated by our previous results, where, in a quark-lepton complementarity (QLC) model we predicted the values of $\theta_{13}^{PMNS}=(9_{-2}^{+1})^{\circ}$ and $\theta_{23}^{PMNS}=(40.60_{-0.3}^{+0.1})^{\circ}$. In the QLC model the non-trivial correlation between $CKM_4$ and $PMNS_4$ mixing matrix is given by the correlation matrix $V_{c_{4}}$. Monte Carlo simulations are performed to estimate the texture of $V_{c4}$ followed by the calculation of $PMNS_4$ using the equation, $U_{PMNS_{4}}= (U_{CKM_{4}} . \psi_{4})^{-1}.V_{c_{4}}$, where $\psi_{4}$ is a diagonal phase matrix. The sterile neutrino mixing angles, $\theta_{14}^{PMNS}$, $\theta_{24}^{PMNS}$ and $\theta_{34}^{PMNS}$ are assumed to be freely varying between $(0-\pi/4)$ and obtained results which are consistent with the data available from various experiments, like No$\nu$A, MINOS, SuperK, Ice Cube-DeepCore. In further investigation, we analytically obtain approximately similar ranges for various neutrino mixing parameters $\mid{ U_{\mu 4}}\mid ^2$ and $\mid{ U_{\tau 4}}\mid ^2$.Comment: 16 pages, 4 tables, 7 figures(with subfigures, total 14 figures

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.Comment: Latex 10pages including 3 postscript figure

Superfield Approach to Nilpotency and Absolute Anticommutativity of Conserved Charges: 2D non-Abelian 1-Form Gauge Theory

We exploit the theoretical strength of augmented version of superfield approach (AVSA) to Becchi-Rouet-Stora-Tyutin (BRST) formalism to express the nilpotency and absolute anticommutativity properties of the (anti-)BRST and (anti-)co-BRST conserved charges for the two $(1+1)$-dimensional (2D) non-Abelian 1-form gauge theory (without any interaction with matter fields) in the language of superspace variables, their derivatives and suitable superfields. In the proof of absolute anticommutativity property, we invoke the strength of Curci-Ferrari (CF) condition for the (anti-)BRST charges. No such outside condition/restriction is required in the proof of absolute anticommutativity of the (anti-)co-BRST conserved charges. The latter observation (as well as other observations) connected with (anti-)co-BRST symmetries and corresponding conserved charges are novel results of our present investigation. We also discuss the (anti-)BRST and (anti-)co-BRST symmetry invariance of the appropriate Lagrangian densities within the framework of AVSA. In addition, we dwell a bit on the derivation of the above fermionic (nilpotent) symmetries by applying the AVSA to BRST formaism where only the (anti-)chiral superfields are used.Comment: LaTeX file, 33 pages, journal referenc

Solar Neutrinos: Spin Flavour Precession and LMA

The time dependence that appears to be hinted by the data from the first 13 years of the solar neutrino Gallium experiments is viewed as resulting from a partial conversion of active neutrinos to light sterile ones through the resonant interaction between the magnetic moment of the neutrino and a varying solar field. A summary of the model and its predictions are presented for the forthcoming experiments Borexino and LENS.Comment: 6 pages, 3 figures, contribution to 12th Lomonosov Conference in Elementary Particle Physics, Moscow, Aug 24-31 (2005

Modified 2D Proca Theory: Revisited Under BRST and (Anti-)Chiral Superfield Formalisms

Within the framework of Becchi-Rouet-Stora-Tyutin (BRST) approach, we discuss mainly the fermionic (i.e. off-shell nilpotent) (anti-)BRST, (anti-)co-BRST and some discrete dual-symmetries of the appropriate Lagrangian densities for a two (1+1)-dimensional (2D) modified Proca (i.e. a massive Abelian 1-form) theory without any interaction with matter fields. One of the novel observations of our present investigation is the existence of some kinds of restrictions in the case of our present St\"{u}ckelberg-modified version of the 2D Proca theory which is not like the standard Curci-Ferrari (CF)-condition of a non-Abelian 1-form gauge theory. Some kinds of similarities and a few differences between them have been pointed out in our present investigation. To establish the sanctity of the above off-shell nilpotent (anti-)BRST and (anti-)co-BRST symmetries, we derive them by using our newly proposed (anti-)chiral superfield formalism where a few specific and appropriate sets of invariant quantities play a decisive role. We express the (anti-)BRST and (anti-)co-BRST conserved charges in terms of the superfields that are obtained after the applications of (anti-)BRST and (anti-)co-BRST invariant restrictions and prove their off-shell nilpotency and absolute anticommutativity properties, too. Finally, we make some comments on (i) the novelty of our restrictions/obstructions, and (ii) the physics behind the negative kinetic term associated with the pseudo-scalar field of our present theory.Comment: LaTeX file, 58 pages, Journal reference give

Predictions from non trivial Quark-Lepton complementarity

The complementarity between the quark and lepton mixing matrices is shown to provide robust predictions. We obtain these predictions by first showing that the matrix V_M, product of the quark (CKM) and lepton (PMNS) mixing matrices, may have a zero (1,3) entry which is favored by experimental data. We obtain that any theoretical model with a vanishing (1,3) entry of V_M that is in agreement with quark data, solar, and atmospheric mixing angle leads to $\theta_{13}^{PMNS}=(9{^{+1}_{-2}})^\circ$. This value is consistent with the present 90% CL experimental upper limit. We also investigate the prediction on the lepton phases. We show that the actual evidence, under the only assumption that the correlation matrix V_M product of CKM and PMNS has a zero in the entry (1,3), gives us a prediction for the three CP-violating invariants J, S_1, and S_2. A better determination of the lepton mixing angles will give stronger prediction for the CP-violating invariants in the lepton sector. These will be tested in the next generation experiments. Finally we compute the effect of non diagonal neutrino mass in "l_i -> l_j gamma" in SUSY theories with non trivial Quark-Lepton complementarity and a flavor symmetry. The Quark-Lepton complementarity and the flavor symmetry strongly constrain the theory and we obtain a clear prediction for the contribution to "mu -> e gamma" and the "tau" decays "tau -> e gamma" and "tau -> mu gamma". If the Dirac neutrino Yukawa couplings are degenerate but the low energy neutrino masses are not degenerate, then the lepton decays are related among them by the V_M entries. On the other hand, if the Dirac neutrino Yukawa couplings are hierarchical or the low energy neutrino masses are degenerate, then the prediction for the lepton decays comes from the CKM hierarchy.Comment: 15 pages, 5 figures, ws-ijmpa class included, Proceedings of the CTP Symposium on Sypersymmetry at LH

(Anti-)Chiral Superfield Approach to Interacting Abelian 1-Form Gauge Theories: Nilpotent and Absolutely Anticommuting Charges

We derive the off-shell nilpotent (fermionic) (anti-)BRST symmetry transformations by exploiting the (anti-)chiral superfield approach (ACSA) to Becchi-Rouet-Stora-Tyutin (BRST) formalism for the interacting Abelian 1-form gauge theories where there is a coupling between the U(1) Abelian 1-form gauge field and Dirac as well as complex scalar fields. We exploit the (anti-)BRST invariant restrictions on the (anti-)chiral superfields to derive the fermionic symmetries of our present D-dimensional Abelian 1-form gauge theories. The novel observation of our present investigation is the derivation of the absolute anticommutativity of the nilpotent (anti-)BRST charges despite the fact that our ordinary D-dimensional theories are generalized onto the (D, 1)-dimensional (anti-)chiral super submanifolds (of the general (D, 2)-dimensional supermanifold) where only the (anti-)chiral expansions of the (anti-)chiral superfields have been taken into account. We also discuss the nilpotency of the (anti-)BRST charges and (anti-)BRST invariance of the Lagrangian densities of our present theories within the framework of ACSA to BRST formalism.Comment: LaTeX file, 20 pages, journal versio