18903505
DARK MATTER CANDIDATE IN A HEAVY HIGGS MODEL: DIRECT DETECTION RATES
We investigate direct detection rates for Dark Matter candidates arise in a SU(2)L×U(1)Y with an additional doublet Higgs proposed by Barbieri, Hall and Rychkov. We refer to this model as "Heavy Higgs Model". The Standard Model Higgs mass comes out from this model is very heavy, so there is very slim chance that there is no Higgs boson mass below 200 GeV. The additional Higgs boson develops neither any VEV due to the choice of coefficient of the scalar potential of the model nor it has any coupling with fermions due to the incorporation of a discrete parity symmetry. Thus, the neutral components of the extra doublet are stable and can be considered as probable candidate of Cold Dark Matter. We have made calculations for three different types of Dark Matter experiments, namely, 76Ge (like GENIUS), DAMA (NaI) and XENON (131Xe). Also demonstrated the annual variation of Dark Matter detection in case of all three
15935653
Effect of flavour oscillations on the detection of supernova neutrinos
Neutrinos and antineutrinos of all three flavours are emitted during the post-bounce phase of a core-collapse supernova with having average energies more than that of They can be detected by the new earthbound detectors like SNO and Super-Kamiokande which are sensitive to neutrinos of all three flavours. In this letter we consider the effect of flavour oscillations on the neutrino flux and their expected number of events at the detector. We do a three-generation analysis and for the mass and mixing schemes we first consider the threefold maximal mixing model consistent with the solar and the atmospheric neutrino data and next a scenario with one m2~10-11 eV2 (solar range) and the other m2~10-18 eV2, for which the oscillation length is of the order of the supernova distance. In both these scenarios there are no matter effects in the resultant neutrino spectrum and one is concerned with vacuum oscillations. We find that though neutrino oscillations result in a depletion in the number of e and coming from the supernova, the actual signals at the detectors are appreciable enhanced as the e and energy spectra become harder.
16847898
Mass and Scalar Cross-sections for Neutralino Dark Matter in Anomaly Mediated Supersymmetry Breaking Model
We consider the neutralino to be the lightest supersymmetric particle in the framework of the minimal anomaly mediated supersymmetry breaking (mAMSB) model. We have studied the variation of the neutralino mass with the supersymmetric parameters. Considering these neutralinos to be candidates for weakly interacting massive particles (WIMPs) or cold dark matter, we have calculated the neutralino nucleon scalar cross sections and compared them with the results of the DAMA-NaI neutralino direct detection search. From this study, we observe that the mAMSB model results cannot explain the allowed region in WIMP mass and WIMP–nucleon scalar cross-section space obtained from the annual modulation signature in the DAMA-NaI experiment.
118940895
"Bimaximal + Democratic"type neutrino mass matrix in view of quark-lepton complementarity
We demonstrate that `Bimaximal + Democratic' type neutrino mass matrix can accommodate the deviation of $\theta_\odot$ from its maximal value which referred in the literature as `quark-lepton complementarity' along with the other present day neutrino experimental results, namely, atmospheric, CHOOZ, neutrinoless double beta decay ($\beta\beta_{0\nu}$) and result obtained from WMAP experiment. We define a function $\chi_p$ in terms of solar and atmospheric neutrino mass squared differences and solar neutrino mixing angle (obtained from different experiments and our proposed texture). The masses and mixing angles are expressed in terms of three parameters in our proposed texture. The allowed region of the texture parameters is obtained through minimization of the above function. The proposed texture crucially depends on the value of the experimental results of $\beta\beta_{0\nu}$ experiment among all other above mentioned experiments. If, in future, $\beta\beta_{0\nu}$ experiments, namely, MOON, EXO, GENIUS shift the lower bound on $$ at the higher side by one order, the present texture will be ruled out.
11939062
Unparticle decay of neutrinos and it's effect on ultra high energy neutrinos
The unparticle is proposed by Georgi as a conceptual new physics beyond the standard model to describe the low energy sector of a nontrivial scale invariant sector of an effective theory. We consider the neutrino decay in unparticle scenario and investigate the effect of such decay for the case of ultra high energy neutrinos from GRB. The effect on the detection yield of these neutrinos are also probed for a kilometer scale ice-Cerenkov detector.
118595488
Generalizing thawing dark energy models: the standard vis-à-vis model independent diagnostics
We propose a two parameter generalization for the dark energy equation of state (EOS) wX for thawing dark energy models which includes PNGB, CPL and Algebraic thawing models as limiting cases and confront our model with the latest observational data namely SNe Ia, OHD, CMB, BOSS data. Our analysis reveals that the phantom type of thawing dark energy is favoured upto 2� confidence level. These results also show that thawing dark e nergy EOS is not unique from observational point of view. Though different thawing dark energy models are not distinguishable from each other from best-fit values (upto 2� C.L.s) of matter density parameter ( 0) and hubble parameter (H0) at present epoch, best-fit plots of linear growth of matter perturbation (f ) and average deceleration parameter (qav); the difference indeed reflects in best-fit variations of thawing dark energy EOS, model-independent geometrical diagnostics like the statefinder pair {r, s} and Om3 parameter. We are thus led to the conclusion that unlike the standard observables ( 0, H0, f , qav), the model-independent pa� � ,
120089980
ELECTROMAGNETIC MASS DIFFERENCES.
Abstract In Cottingham's approach to electromagnetic masses ( δm ) one encounters the problem of unknown subtractions in the fixed mass dispersion relations for the virtual Compton scattering amplitude. We avoid this problem and express δm in terms of measurable quantities, assuming knowledge of light-cone singularities of the electro-magnetic current commutator.
121043964
INELASTIC e--p SCATTERING DATA AND A NEW PARTON MODEL.
120289082
NOTE ON THE MOST PROBABLE NUMBER OF PARTONS IN PARTON MODELS.