116501299
Background gluon effects on B ---> X(s) gamma gamma
We consider non-perturbative QCD effects on the energy spectrum of either one of the photons in B -> X_s gamma gamma. These are due to the subprocesses in which a charm quark loop interacts with a self-consistently produced background static QCD field. The magnitude is estimated to be a few percents in B -> X_s gamma gamma, but can be quite substantial in B_s -> gamma gamma. An extension of the Euler-Heisenberg Lagrangian is given.
121540499
Study of the flavor changing neutral current decay mode B ---> K gamma gamma
We study the neutral current flavour changing rare decay mode $B\to K \gamma \gamma $ within the framework of Standard Model, including the long distance contributions. It is found that these long distance contributions can larger than the short distance contribution.
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.
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
118843594
Low-energy theorems for spin-1 Compton scattering
SummaryUsing analyticity, the classical low-energy theorems are derived for Compton scattering of a spin-1 target. Exploiting the threshold behavior we are also able to derive the quadrupole-moment theorem recently given by Pais.RiassuntoUsando l’analiticità, si derivano i teoremi classici di bassa energia per lo scattering Compton di un bersaglio di spin 1. Sfruttando l’andamento alla soglia siamo anche in grado di dedurre il teorema del momento di quadrupolo enunciato recentemente da Pais.РезюмеИспользуя аналитичность, выводятся классические теоремы малых энергий для комптоновского рассеяния на мишени со спином 1. Воспользовавшись пороговым поведением, мы также можем получить теорему квадрупольного момента, недавно полученную Пейсом.
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.
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.
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.
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.
56030556
Primordial blackholes and gravitational waves for an inflection-point model of inflation
Abstract In this article we provide a new closed relationship between cosmic abundance of primordial gravitational waves and primordial blackholes that originated from initial inflationary perturbations for inflection-point models of inflation where inflation occurs below the Planck scale. The current Planck constraint on tensor-to-scalar ratio, running of the spectral tilt, and from the abundance of dark matter content in the universe, we can deduce a strict bound on the current abundance of primordial blackholes to be within a range, 9.99712 × 10 − 3 Ω PBH h 2 9.99736 × 10 − 3 .