118476324
Inflamagnetogenesis redux: Unzipping sub-Planckian inflation via various cosmoparticle probes
Abstract In this paper I introduce a precise constraint on primordial magnetogenesis, for a generic class of single-field inflationary model followed by small field excursion below the Planck scale. I also establish a connection between the magnetic field at the present epoch and primordial gravity waves (r) via non-vanishing CP asymmetry parameter ( ϵ CP ), which triggers the leptogenesis scenario. Finally, I explore various hidden cosmophenomenological features of theoretical CMB B-mode polarization spectra, which can be treated as a significant probe to put further stringent constraint on low and high scale small field inflationary models after releasing the Planck B-mode polarization data.
119187831
Reheating and leptogenesis in a SUGRA inspired brane inflation
Abstract We have studied extensively phenomenological implications in a specific model of brane inflation driven by background supergravity (Choudhury and Pal, 2011) [1] , via thermal history of the universe and leptogenesis pertaining to the particle physics phenomenology of the early universe. Using the one loop corrected inflationary potential we have investigated for the analytical expression as well as the numerical estimation for brane reheating temperature for standard model particles. This results in some novel features of reheating from this type of inflation which have serious implications in the production of heavy Majorana neutrinos needed for leptogenesis through the reheating temperature. We have also derived the expressions for the gravitino abundance during reheating and radiation dominated era. We have further estimated different parameters at the epoch of phase transition and revealed their salient features. At the end we have explicitly given an estimate of the amount of CP violation through the effective CP phase which is related to baryon asymmetry as well as gravitino dark matter abundance.
119262207
Higgs inflation from new Kähler potential
Abstract We introduce a new class of models of Higgs inflation using the superconformal approach to supergravity by modifying the Kahler geometry. Using the above-mentioned mechanism, we construct a phenomenological functional form of a new Kahler potential followed by construction of various types of models which are characterized by a superconformal symmetry breaking parameter χ . Depending on the numerical values of χ we classify the proposed models into three categories. Models with minimal coupling are identified by χ = ± 2 3 branch which are made up of shift symmetry preserving flat directions. We also propose various other models by introducing a non-minimal coupling of the inflaton field to gravity described by χ ≠ 2 3 branch. We employ all these proposed models to study the inflationary paradigm by estimating the major cosmological observables and confront them with recent observational data from WMAP9 along with other complementary data sets, as well as independently with PLANCK. We also mention an allowed range of non-minimal couplings and the Yukawa type of couplings appearing in the proposed models used for cosmological parameter estimation.
115768362
Collider constraints on Gauss-Bonnet coupling in warped geometry model
In this paper the requirement of a warp solution in an Einstein-Gauss-Bonnet 5D warped geometry is shown to fix the signature of Gauss-Bonnet coupling ($\alpha_{5}$). Further, imposing the phenomenological constraints, obtained from the recently observed Higgs like scalar mass as well as $\mu$ parameter of the decay channels ${H}_{0}\rightarrow\gamma\gamma,\tau{\bar \tau}$ explored in ATLAS and CMS detectors, we obtain a stringent bound on $\alpha_{5}$ within $(4.8 - 5.1)\times 10^{-7}$.
118404858
Brane inflation: A field theory approach in background supergravity
We propose a model of inflation in the framework of brane cosmology driven by background supergravity. Starting from bulk supergravity we construct the inflaton potential on the brane and employ it to investigate for the consequences to inflationary paradigm. To this end, we derive the expressions for the important parameters in brane inflation, which are somewhat different from their counterparts in standard cosmology, using the one loop radiative corrected potential. We further estimate the observable parameters and find them to fit well with recent observational data. We have studied extensively reheating phenomenology, which explains the thermal history of the universe and leptogenesis through the production of thermal gravitino pertaining to the particle physics phenomenology of the early universe.
119286198
A step toward exploring the features of Gravidilaton sector in Randall–Sundrum scenario via lightest Kaluza–Klein graviton mass
In this paper we study the role of the 5D Gauss–Bonnet corrections and two-loop higher genus contribution to the gravity action in type IIB string theory inspired low energy supergravity theory in the light of gravidilatonic interactions on the lightest Kaluza–Klein graviton mass spectrum. From the latest constraints on the lightest Kaluza–Klein graviton mass as obtained from the ATLAS dilepton search in 7 TeV proton–proton collision experiments, we have shown that due to the presence of Gauss–Bonnet and string loop corrections, the warping solution in an $$\mathbf{AdS_{5}}$$AdS5 bulk is quite distinct from the Randall–Sundrum scenario. We discuss the constraints on the model parameters to fit with the present ATLAS data.
123597715
QUARK MODEL ANALYSIS OF RADIATIVE PION DECAY
We present a relativistic quark model analysis of radiative pion decay using a systematic application of Low’s bremsstrahlung theorem. Our findings agree reasonably with recent definitive experimental results by the Russian group on the structure-dependent components of the πγA and πγV amplitudes, with the latter agreeing remarkably well with the CVC prediction. Finally we analyze between the quark model calculation and the current algebra prediction and establish the equivalence of the two within the limit of a local πqq interaction.
17728622
A note on low scale unification and gamma–gamma scattering
Abstract In this note we study an interesting effect of low energy gravity on photon-photon scattering at high energies.
121418463
Tests of second-class currents
Abstract We argue that the presence of second-class neutral currents can be tested from the observations of η→π 0 ν l ν l and electron polarisation in η → π 0 e + e - . Consequences of this model in η → π ± e ∓ ν e , τ ± → ηπ ± ν τ and τ ± → ωπ ± ν τ decays which would establish second-class charged currents are also discussed.
7618332
SIGNATURES OF NEW PHYSICS IN DILEPTONIC B-DECAYS
Leptonic decays of B-mesons are theoretically very clean probes for testing the Standard Model (SM) and possible physics beyond it. Amongst the various leptonic decays of the B-meson, the pure dileptonic decay B → l+ l- is very important, as this mode is helicity suppressed in the SM but can be substantially enhanced in some of the models beyond the SM, such as supersymmetric (SUSY) theories and the two Higgs doublet model (2HDM). Although the purely dileptonic decay mode is helicity suppressed in the SM its associated mode B → l+ l-γ does not have the same suppression, due to the presence of γ in the final state. In this paper we will also analyze the effects of enhanced Z-penguins on these two decay modes.
119921028
Confinement in a Bethe-Salpeter model with logarithmic potential
We show that the covariant Bethe-Salpeter equation for two scalar quarks confined through a kernel of the form $K\ensuremath{\sim}{[{(p\ensuremath{-}{p}^{\ensuremath{'}})}^{2}]}^{\ensuremath{-}\frac{3}{2}}$ possesses a discrete spectrum: this kernel is a simple covariant generalization of the potential in configuration space proportional to $\mathrm{ln}r$. To investigate the spectrum, we adopt a new approximation scheme to convert the covariant Bethe-Salpeter equation into a three-dimensional one, the consistency of the scheme being checked by applying it to the Wick-Cutkosky equation for the covariant Coulomb problem and obtaining a Balmer-type formula. The spectrum as revealed by investigating the $S$-wave part of the resulting three-dimensional equation by semiclassical methods is essentially of the type obtained from the Schr\"odinger equation with a $\mathrm{ln}r$ potential; relativistic effects depress the energy levels.