118190750
Production of two higgses at the Large Hadron Collider in CP-violating MSSM
A bstractProduction of two Higgs bosons is studied in a CP violating supersymmetric scenario at the Large Hadron Collider with Ecm = 14 TeV. There exists a region where a very light Higgs ≲ 50 GeV could not be probed by LEP experiment. This leads to so called ’LEP hole’ region. Recently LHC found a Higgs boson around ~ 125 GeV, which severely constrains the possibility of having lighter Higgs bosons, which cannot be detected, i.e., buried Higgs, in this model. We investigate the possibility of buried Higgs bosons along with the direct and indirect bounds coming from LEP, LHC and other experiments. In particular we take into account the constraints from EDM and from B-observables. We analyse first the case where a Higgs boson mass is around 125 GeV and the other two Higgs masses are below 100 GeV and not observed so far. In the second case the lightest Higgs boson mass is around 125 GeV and the other two are decoupled. We analyse the production of two Higgses and their decay modes leading to various final states for these benchmark points. We perform a collider simulation with PYTHIA and Fastjet where we consider all the major backgrounds. Among the final states we have analysed, we find that 2b + 2τ is promising and the signal significance is 5σ at an integrated luminosity ≲ 10 fb−1. For some benchmark points it is also possible to observe the light Higgs mass peak. We also explore the leptonic final state which could be instrumental in the precision measurement of a very light Higgs.
121486698
Working group report: Physics at the Large Hadron Collider
Abstract.This is a summary of the activities of the Physics at the LHC working group in the XIth Workshop on High Energy Physics Phenomenology (WHEPP-XI) held at the Physical Research Laboratory, Ahmedabad, India in January 2010. We discuss the activities of each sub-working group on physics issues at colliders such as Tevatron and Large Hadron Collider (LHC). The main issues discussed involve (1) results on W mass measurement and associated QCD uncertainties, (2) an attempt to understand the asymmetry measured at Tevatron in the top quark production, and (3) phenomenology of warped space dimension model.
117174894
Probing Higgs bosons via the type III seesaw mechanism at the LHC
We show that the type III seesaw mechanism opens up a promising possibility of searching the Higgs boson in the $b \bar b$ channel through the Higgs production associated with a charged lepton coming from the decay of the triplet seesaw particle. In particular we look for the $2b$ signals with trileptons or same-sign dileptons to construct the Higgs and the triplet fermion mass and calculate the reach with the integrated luminosity of 10 fb$^{-1}$ at the 14 TeV LHC.
118308113
Higgs production in CP-violating supersymmetric cascade decays: probing the ‘open hole’ at the Large Hadron Collider
A benchmark CP-violating supersymmetric scenario (known as ‘CPX-scenario’ in the literature) is studied in the context of the Large Hadron Collider (LHC). It is shown that the LHC, with low to moderate accumulated luminosity, will be able to probe the existing ‘hole’ in the $ {m_{{h_1}}} $-tan β plane, which cannot be ruled out by the LEP data. We explore the parameter space with cascade decay of third generation squarks and gluino with CP-violating decay branching fractions. We propose a multi-channel analysis to probe this parameter space some of which are background free at an integrated luminosity of 5-10 fb−1. Specially, multi-lepton final states (3l, 4l and like sign di-lepton) are almost background free and have 5σ reach for the corresponding signals with very early data of LHC for both 14 TeV and 7 TeV center of mass energy.
119292092
Boosted top quarks in supersymmetric cascade decays at the LHC
At the LHC, a generic supersymmetric cascade can be a source of top quark. Specifically third generation squarks and gluino are the major sources of top quark which could also be boosted. In this article, we have shown that jet substructure algorithm can be very useful in identifying such boosted top quarks in the cascade. We take inclusive three jets plus zero lepton plus missing energy final state and try to reconstruct at least one hadronically decaying top quark by using top tagging techniques which has good prospect at the LHC.
120699236
TOPOLOGICAL ASPECTS OF CHIRAL ANOMALY, ORIGIN OF MASS AND ELECTROWEAK THEORY
It is here shown that the topological property of a fermion which gives rise to the fermion number and is related to chiral anomaly may be taken to lead to weak interaction gauge bosons when currents are written in chiral form. The gauge bosons attain mass topologically through the generation of internal helicities and thus no Higgs scalar is needed to have spontaneous symmetry breaking. Moreover the group structure SU(2)×U(1) is inbuilt here for electroweak unification. The Weinberg angle gets a physical meaning and strangeness changing neutral lepton current interaction is automatically forbidden. This formalism also suggests that at very high temperature, weak interaction will be of long range in nature.
122605004
Clan structure and intermittency in proton-nucleus interactions at high energy
In this paper we examine the similarity between clan structure and self-similar cascading in high energy proton-nucleus interactions at 70 GeV/c in emulsion. The investigation shows that the negative bionomial fitting parameterk can be used for the evaluation of factorial moments in intermittency studies and that these exhibit similar behaviour with those derived from nonstatistical procedure. The results of our study signify compatibility between clan cascading and self-similar cascading in soft hadroization processes.
122353086
POSSIBLE WEAK INTERACTION OF PHOTONS AND EMISSION OF NEUTRINOS FROM STARS.
121399031
Geometrical aspects of magnetic monopoles
The possible topological structures of elementary particles have been investigated to explore the possibility of the existence of magnetic monopoles. It is pointed out that when an elementary charged particle is depicted as an extended body such that the orientation of the internal space (“internal helicity”) defines the fermion number, the global conservation of this does not allow the existence of a magnetic monopole. Again it is argued that when anisotropy is introduced in the microlocal space-time depicting the internal space of hadrons, this gives rise to the internal symmetry algebra and no non-Abelian gauge fields and Higgs scalars are necessary to have a grand unified scheme of interactions. This avoids theSU2 and GUT monopoles. Besides, in this formalism, baryon number corresponds to the orientation or internal helicity of the composite system and the global conservation of this quantum number is found to be a consequence of Lorentz invariance. This forbids the existence of any sort of cosmological monopole in this Lorentz invariant Universe.
123023180
Neutrino theory of light from the viewpoint of the Bethe-Salpeter equation
The possibility that the photon may be a composite state of a neutrino-antineutrino pair has been examined here in the framework of the Bethe-Salpeter equation. The formalism takes into account the photon-neutrino weak interaction. It is shown that in this special case, when the exchanged particle mass $\ensuremath{\mu}=0$ as well as the total mass of the interacting spinors $m=0$, we must introduce a cutoff factor $\ensuremath{\Lambda}$ corresponding to the introduction of a fundamental length ${l}_{0}(\ensuremath{\Lambda}\ensuremath{\sim}\frac{1}{{l}_{0}})$. The solution of the Bethe-Salpeter equation is found to be associated with a discrete spectrum and the energy expression is found to be of the form ${E}^{2}=2{\ensuremath{\Lambda}}^{2}[2\ensuremath{-}(\frac{1}{{n}^{2}}){(\frac{{g}^{2}}{4\ensuremath{\pi}})}^{2}]$, where $n=1,2,3\dots{}$, and $g$ denotes the photon-neutrino weak-coupling strength.