119118215
AUGMENTED SUPERFIELD APPROACH TO NON-YANG–MILLS SYMMETRIES OF JACKIW–PI MODEL: NOVEL OBSERVATIONS
We derive the off-shell nilpotent and absolutely anti-commuting Becchi–Rouet–Stora–Tyutin (BRST) as well as anti-BRST symmetry transformations corresponding to the non-Yang–Mills (NYM) symmetry transformations of (2+1)-dimensional Jackiw–Pi (JP) model within the framework of "augmented" superfield formalism. The Curci–Ferrari (CF) restriction, which is a hallmark of non-Abelian one-form gauge theories, does not appear in this case. One of the novel features of our present investigation is the derivation of proper (anti-)BRST symmetry transformations corresponding to the auxiliary field ρ that cannot be derived by any conventional means.
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.
118739941
Novel symmetries in vector Schwinger model
We derive nilpotent and absolutely anticommuting (anti-)co-BRST symmetry transformations for the bosonized version of (1+1)-dimensional (2D) vector Schwinger model. These symmetry transformations turn out to be the analog of co-exterior derivative of differential geometry as the total gauge-fixing term remains invariant under it. The exterior derivative is realized in terms of the (anti-)BRST symmetry transformations of the theory whereas the bosonic symmetries find their analog in the Laplacian operator. The algebra obeyed by these symmetry transformations turns out to be exactly same as the algebra obeyed by the de Rham cohomological operators of differential geometry.
118367187
A NOTE ON THE (ANTI-)BRST INVARIANT LAGRANGIAN DENSITIES FOR THE FREE ABELIAN 2-FORM GAUGE THEORY
We show that the previously known off-shell nilpotent and absolutely anticommuting (sb sab + sab sb = 0) Becchi–Rouet–Stora–Tyutin (BRST) transformations (sb) and anti-BRST transformations (sab) are the symmetry transformations of the appropriate Lagrangian densities of a four (3+1)-dimensional (4D) free Abelian 2-form gauge theory which do not explicitly incorporate a very specific constrained field condition through a Lagrange multiplier 4D vector field. The above condition, which is the analogue of the Curci–Ferrari restriction of the non-Abelian 1-form gauge theory, emerges from the Euler–Lagrange equations of motion of our present theory and ensures the absolute anticommutativity of the transformations s(a)b. Thus, the coupled Lagrangian densities, proposed in our present investigation, are aesthetically more appealing and more economical.
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.
118967100
PSEUDO-HERMITIAN INTERACTIONS IN DIRAC THEORY: EXAMPLES
We consider a couple of examples to study the pseudo-Hermitian interaction in relativistic quantum mechanics. Rasbha interaction, commonly used to study the spin Hall effect, is considered with imaginary coupling. The corresponding Dirac Hamiltonian is shown to be parity pseudo-Hermitian. In the other example we consider parity pseudo-Hermitian scalar interaction with arbitrary parameter in Dirac theory. In both cases we show that the energy spectrum is real and all the other features of nonrelativistic pseudo-Hermitian formulation are present. Using the spectral method, the positive definite metric operator (η) has been calculated explicitly for both the models to ensure positive definite norms for the state vectors.
51734656
Screening correlators with chiral fermions
We study screening correlators of quark-antiquark composites at T=2T{sub c}, where T{sub c} is the QCD phase transition temperature, using overlap quarks in the quenched approximation of lattice QCD. As the lattice spacing is changed from 1/4T to a=1/6T and 1/8T, we find that screening correlators change little, in contrast with the situation for other types of lattice fermions. All correlators are close to the ideal gas prediction at small separations. The long distance falloff is clearly exponential, showing that a parametrization by a single screening length is possible at distances z{>=}1/T. The correlator corresponding to the thermal vector is close to the ideal gas value at all distances, whereas that for the thermal scalar deviates at large distances. This is examined through the screening lengths and momentum space correlators. There is strong evidence that the screening transfer matrix does not have reflection positivity.
118484055
Symmetry energy from fragment observables in the canonical thermodynamic model
Different formulas relating measurable fragment isotopic observables to the symmetry energy of excited nuclei were proposed and applied to the analysis of heavy ion collision data in the recent literature. In this article, we examine the quality of the different expressions in the framework of the McGill canonical thermodynamic model (CTM). We show that even in the idealized situation of canonical equilibrium and in the absence of secondary decay, these formulas do not give a precise reconstruction of the symmetry energy of the fragmenting source. However, both isotopic widths and isoscaling appear very well correlated to the physical symmetry energy.
125232875
THE EMC EFFECT AND HIGH TRANSVERSE MOMENTUM JETS
118620767
Neutrino Mass Matrices with a Texture Zero and a Vanishing Minor
We study the implications of the simultaneous existence of a texture zero and a vanishing minor in the neutrino mass matrix. There are 36 possible texture structures of this type, 21 of which reduce to two texture zero cases which have, already, been extensively studied. Of the remaining 15 textures only six are allowed by the current data. We examine the phenomenological implications of the allowed texture structures for Majorana type CP-violating phases, 1-3 mixing angle, and Dirac type CP-violating phase. All these possible textures can be generated through the seesaw mechanism and realized in the framework of discrete Abelian flavor symmetry. We present the symmetry realization of these texture structures.
14702466
Right-Chiral Sneutrino LSP in mSUGRA: Event characteristics of NLSP at the LHC
We study a supersymmetric scenario where the lighter tau-sneutrino is the lightest supersymmetric particle, while the lighter stau-state is the next lightest. Such a scenario can be motivated within the framework of minimal supergravity, with just the addition of a right-chiral neutrino superfield. Such a spectrum leads to rather unusual signals of supersymmetry, showing stable tracks of the stau in the muon chambers. We study the event characteristics of the long-lived staus at the LHC and demonstrate that the stau tracks can be distinguished from the muonic ones through proper kinematic cuts which also enable one to remove all standard model backgrounds.