1,247 research outputs found
Dark Matter in B-L Extended MSSM Models
We analyze the dark matter problem in the context of supersymmetric
U(1)_{B-L} model. In this model, the lightest neutalino can be the B-L gaugino
widetilde {Z}_{B-L} or the extra Higgsinos widetilde{chi}_{1,2} dominated. We
compute the thermal relic abundance of these particles and show that, unlike
the LSP in MSSM, they can account for the observed relic abundance with no
conflict with other phenomenological constraints. The prospects for their
direct detection, if they are part of our galactic halo, are also discussed.Comment: 11 pages, 9 figures. Published versio
Impact of Satellite Sea Surface Salinity Observations on ENSO Predictions from the NASA/GMAO Seasonal Forecast System
We assess the impact of satellite sea surface salinity (SSS) observations on dynamical ENSO forecasts. Assimilation of SSS improves the mixed layer depth (MLD) and modulates the Kelvin waves associated with ENSO. In column 2, the initialization differences between experiments that assimilate SSS minus those withholding SSS assimilation are presented. Column 3 shows examples of forecasts generated for the different phases of ENSO assimilating the different satellite SSS. In general, for all phases of ENSO, SSS assimilation improves forecasts. The far right column compares ensemble means for assimilation of individual and combined SMOS, Aquarius, and SMAP SSS forecasts. Finally, the latest forecasts are presented comparing assimilation versus no- assimilation of satellite SSS for single forecasts over the last year
Electroweak Symmetry Breaking and Proton Decay in SO(10) SUSY-GUT with TeV W_R
In a recent paper, we proposed a new class of supersymmetric SO(10) models
for neutrino masses where the TeV scale electroweak symmetry is SU(2)_L\times
SU(2)_R\times U(1)_{B-L} making the associated gauge bosons W_R and Z'
accessible at the Large Hadron Collider. We showed that there exists a domain
of Yukawa coupling parameters and symmetry breaking patterns which give an
excellent fit to all fermion masses including neutrinos. In this sequel, we
discuss an alternative Yukawa pattern which also gives good fermion mass fit
and then study the predictions of both models for proton lifetime. Consistency
with current experimental lower limits on proton life time require the squark
masses of first two generations to be larger than ~ 1.2 TeV. We also discuss
how one can have simultaneous breaking of both SU(2)_R\times U(1)_{B-L} and
standard electroweak symmetries via radiative corrections.Comment: 31 pages, 5 figures, 4 tables
The Symmetries of Nature
The study of the symmetries of nature has fascinated scientists for eons. The application of the formal mathematical description of
symmetries during the last century has produced many breakthroughs in
our understanding of the substructure of matter. In this talk, a number
of these advances are discussed, and the important role that George
Sudarshan played in their development is emphasize
Are There Diquarks in the Nucleon?
This work is devoted to the study of diquark correlations inside the nucleon.
We analyze some matrix elements which encode information about the
non-perturbative forces, in different color anti-triplet diquark channels. We
suggest a lattice calculation to check the quark-diquark picture and clarify
the role of instanton-mediated interactions. We study in detail the physical
properties of the 0+ diquark, using the Random Instanton Liquid Model. We find
that instanton forces are sufficiently strong to form a diquark bound-state,
with a mass of ~500 MeV, which is compatible with earlier estimates. We also
compute its electro-magnetic form factor and find that the diquark is a broad
object, with a size comparable with that of the proton.Comment: Final version, accepted for publication on Phys. Rev.
Identification of a Nerve Growth Factor-Regulated and Epidermal Growth Factor-Regulated Protein-Kinase That Phosphorylates the Protooncogene Product C-Fos
Nerve growth factor (NGF) treatment of rat pheochromocytoma (PC12) cells induces the synthesis of the transcription factor c-Fos, which becomes highly phosphorylated relative to that produced as a result of depolarization of the cell. A peptide derived from the carboxyl terminus of c-Fos (residues 359-370, RKGSSSNEPSSD) containing putative phosphorylation sites was used to detect a NGF-stimulated Fos kinase. NGF treatment of PC12 cells resulted in a rapid activation of a protein kinase which phosphorylated both the c-Fos peptide and authentic c-Fos at its carboxyl terminus. The kinase was selectively activated by NGF and epidermal growth factor but was not induced by depolarization or other agents. The c-Fos peptide was phosphorylated at a serine corresponding to Ser362, a site critically implicated in the capacity of c-Fos to exhibit transrepressive activity [Ofir, R., Dwarki, V. J., Rashid, D. & Verma, I. M. (1990) Nature (London) 348, 80-82)]. The NGF-stimulated Fos kinase may play an important role in regulating the expression and transforming potential of c-Fos
Model Independent Tests for Time Reversal and CP Violations and for CPT Theorem in \Lambda_b and \bar\Lambda_b Two Body Decays
Weak decays of beauty baryons like \Lambda_b (\bar\Lambda_b) into \Lambda
(\bar\Lambda) and V (J^P = 1^-), where both decay products are polarized, offer
interesting opportunities to perform tests of time reversal and CP violations
and of CPT invariance. We propose a model independent parametrization of the
angular distribution and of the polarization of the final resonances, by means
of the spin density matrix. The transverse component of the polarization is
sensitive to time reversal violations, moreover CP-and CPT-sensitive
observables are defined.Comment: 14 page
Extended-soft-core Baryon-Baryon Model II. Hyperon-Nucleon Interaction
The YN results are presented from the Extended-soft-core (ESC) interactions.
They consist of local- and non-local-potentials due to (i) One-boson-exchange
(OBE), with pseudoscalar-, vector-, scalar-, and axial-vector-nonets, (ii)
Diffractive exchanges, (iii) Two-pseudoscalar exchange, and (iv)
Meson-pair-exchange (MPE). This model, called ESC04, describes NN and YN in a
unified way using broken flavor SU(3)-symmetry. Novel ingredients are the
inclusion of (i) the axial-vector-mesons, (ii) a zero in the scalar- and
axial-vector meson form factors. We describe simultaneous fits to the NN- and
YN-data, using four options in the ESC-model. Very good fits were obtained.
G-matrix calculations with these four options are also reported. The obtained
well depths (U_\Lambda, U_\Sigma, U_\Xi) reveal distinct features of ESC04a-d.
The \Lambda\Lambda-interactions are demonstrated to be consistent with the
observed data of_{\Lambda\Lambda}^6He. The possible three-body effects are
investigated by considering phenomenologically the changes of the vector-meson
masses in a nuclear medium.Comment: preprint vesion 66 pages, two-column version 27 pages, 17 figure
Double Type-II Seesaw, Baryon Asymmetry and Dark Matter for Cosmic e^\pm Excesses
We construct a new realization of type-II seesaw for neutrino masses and
baryon asymmetry by extending the standard model with one light and two heavy
singlet scalars besides one Higgs triplet. The heavy singlets pick up small
vacuum expectation values to give a suppressed trilinear coupling between the
triplet and doublet Higgs bosons after the light singlet drives the spontaneous
breaking of lepton number. The Higgs triplet can thus remain light and be
accessible at the LHC. The lepton number conserving decays of the heavy
singlets can generate a lepton asymmetry stored in the Higgs triplet to account
for the matter-antimatter asymmetry in the Universe. We further introduce
stable gauge bosons from a hidden sector, which obtain masses and annihilate
into the Higgs triplet after spontaneous breaking of the associated non-Abelian
gauge symmetry. With Breit-Wigner enhancement, the stable gauge bosons can
simultaneously explain the relic density of dark matter and the cosmic
positron/electron excesses.Comment: 9 pages, 4 figures, minor rewording, final PRD version (in Press
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