121497646
Variational Approach to Higgs Mass Bound
We present a variational study of the Higgs sector of the standard model (with a single doublet Higgs) regarding it as an effective field theory with an ultraviolet cutoff. Our results yield a maximum value of the Higgs mass about 10.8 times the W-mass.
122154027
Relativistic oscillator in a Bethe-Salpeter model: Nonexistence of discrete bound states
We investigate the solutions of the covariant Bethe-Salpeter equation for bound states of a scalar quark-antiquark system with an effective confining kernel which in coordinate four-space behaves as ${R}^{2}$. Using a suitable set of new variables we separate the equation into one-dimensional equations and study the eigenvalue problem. We find that the covariant bound-state Bethe-Salpeter equation with the above kernel possesses only a continuous spectrum.
121960660
Neutral-current cross sections for double-pion production by neutrinos
We have derived expressions for the differential cross sections for two-pion production by the neutral current in a neutrino-induced hadron reaction. We assume a general V, A form of the neutral current with arbitrary admixture of isotopic scalar and vector parts and utilize the algebra of currents and the PCAC (partial conservation of the axial-vector current) hypothesis to obtain the amplitude for ..nu.. + N ..-->.. ..nu.. + N + ..pi.. + ..pi... Two different cases have been studied: (i) Both the outgoing pions are at threshold. (ii) They are produced via the formation of N*. The results are useful to examine the structure of the neutral current.
118238640
HIGH-ORDER LOW-ENERGY THEOREMS FOR NUCLEON COMPTON SCATTERING.
The well-known zero- and first-order (in photon energy) low-energy theorems for nucleon Compton scattering have recently been derived by Abarbanel and Goldberger using only the physical helicity amplitudes for the process and exploiting their kinematical singularities and zeros. We use this approach to study higher-order terms in photon energy and find the result, not entirely new, that four of the six independent helicity amplitudes are determined in second order by the mass, charge, and magnetic moment of the nucleon. Therefore, these parameters together with two structure-dependent constants, which can be interpreted approximately as electric and magnetic polarizabilities, completely determine the Compton scattering to second order in energy. Similar simplifications occurring in the structure of higher-order terms in energy are also discussed. The kinematical singularity structure of helicity amplitudes is a manifestation of Lorentz invariance. We claim to have fully exploited the requirements of Lorentz invariance and therefore to have derived the complete set of low-energy theorems for this process.
10367884
Comment on "New interaction for the enhancement of the Delta I=1/2 amplitude in weak decays"
125314068
Supersymmetric effects in B(s) ---> l+ l- gamma decays
118378176
Brane inflation 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 by confronting with WMAP7 using CAMB. We also analyze the typical energy scale of brane inflation with our model, which resonates well with present estimates from cosmology and standard model of particle physics.
119294991
Low & high scale MSSM inflation, gravitational waves and constraints from Planck
In this paper we will analyze generic predictions of an inflection-point model of inflation with Hubble-induced corrections and study them in light of the Planck data. Typically inflection-point models of inflation can be embedded within Minimal Supersymmetric Standard Model (MSSM) where inflation can occur below the Planck scale. The flexibility of the potential allows us to match the observed amplitude of the TT-power spectrum of the cosmic microwave background radiation with low and high multipoles, spectral tilt, and virtually mild running of the spectral tilt, which can put a bound on an upper limit on the tensor-to-scalar ratio, r ≤ 0.12. Since the inflaton within MSSM carries the Standard Model charges, therefore it is the minimal model of inflation beyond the Standard Model which can reheat the universe with the right thermal degrees of freedom without any dark-radiation.
119125522
Features of warped geometry in presence of Gauss-Bonnet coupling
A bstractWe study the role of the Gauss-Bonnet corrections and two loop higher genus contribution to the gravity action on the Kaluza-Klien modes and their interactions for different bulk fields which enable one to study various phenomenological implications of string loop corrected Gauss-Bonnet modified warped geometry model in one canvas. We have explicitly derived a phenomenological bound on the Gauss-Bonnet parameter so that the required Planck to TeV scale hierarchy can be achieved through the warp factor in the light of recently discovered Higgs like boson at 125GeV. Moreover due to the presence of small perturbative Gauss-Bonnet as well as string loop corrections we have shown that the warping solution can be obtained for both de-Sitter and anti-de-Sitter bulk which is quite distinct from Randall-Sundrum scenario. Finally we have evaluated various interactions among these bulk fields and determined the coupling parameters and the Kaluza-Klien mode masses which is crucial to understand the phenomenology of a string two loop corrected Einstein-Gauss-Bonnet warp geometry.
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.
73661546
Galileogenesis: A new cosmophenomenological zip code for reheating through R-parity violating coupling
In this paper we introduce an idea of leptogenesis scenario in higher derivative gravity induced DBI Galileon framework aka Galileog enesis in presence of one-loop R-parity violating couplings in the background of a low energy effective supergravity setup derived from higher dimensional string theory framework. We have studied extensively the detailed feature of reheating constraints and the cosmophenomenological consequences of thermal gravitino dark matter in light of PLANCK and PDG data. Finally, we have also established a direct cosmophenomenological connection among dark matter relic abundance, reheating temperature and tensor-to-scalar ratio in the context of DBI Galileon inflation.