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R. M. Godbole

Publications and source records attributed to R. M. Godbole.

At least 37 records · Page 2Linked to original sources

Total photoproduction cross-section at very high energy

In this paper we apply to photoproduction total cross-section a model we have proposed for purely hadronic processes and which is based on QCD mini-jets and soft gluon re-summation. We compare the predictions of our model with the HERA data as well as with other models. For cosmic rays, our model predicts substantially higher cross-sections at TeV energies than models based on factorization but lower than models based on mini-jets alone, without soft gluons. We discuss the origin of this difference.

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Using Tau Polarization to probe the Stau Co-annihilation Region of mSUGRA Model at LHC

The mSUGRA model predicts the polarization of the tau coming from the stau to bino decay in the co-annihilation region to be +1. This can be exploited to extract this soft tau signal at LHC and also to measure the tiny mass differences between the stau and the bino LSP. Moreover this strategy will be applicable for a wider class of bino LSP models, where the lighter stau has a right component at least of similar size as the left.

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Electroweak Symmetry Breaking at the LHC

One of the major goals of the Large Hadron Collider is to probe the electroweak symmetry breaking mechanism and the generation of the masses of the elementary particles. We review the physics of the Higgs sector in the Standard Model and some of its extensions such as supersymmetric theories and models of extra dimensions. The prospects for discovering the Higgs particles at the LHC and the study of their fundamental properties are summarised.

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QCD and total cross-sections: photons and hadrons

In this contribution, we discuss a total cross-section model which can be applied to both photon and purely hadronic processes. We find that the model can reproduce photo-production cross-sections, as well as extrapolations of gamma* p processes to gamma p using vector meson dominance models, with minimal modifications from the proton case.

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Zero momentum gluons and the total pp and pbarp cross-sections

We describe a QCD motivated model for total cross-sections which uses the eikonal representation and incorporates QCD mini-jets to drive the rise with energy of the cross-section, while the impact parameter distribution is obtained through the Fourier transform of the transverse momentum distribution of soft gluons emitted in the parton-parton interactions giving rise to mini-jets in the final state. A singular but integral expression for the running coupling constant in the infrared region is part of this model.

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Dictionary of LHC Signatures

We report on a plan to establish a "Dictionary of LHC Signatures", an initiative that started at the WHEPPX workshop in January 2008. This study aims towards the strategy on distinguishing of 3 classes of dark matter motivated scenarios such as R-parity conserved supersymmetry, Little Higgs models with T-parity conservation and Universal Extra Dimensions with KK-parity for generic cases of their realization in wide range of the model space. Discriminating signatures are tabulated and will need a further detailed analysis.

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Minijets, soft gluon resummation and photon cross-sections

We compare the high energy behaviour of hadronic photon-photon cross-sections in different models. We find that the photon-photon cross-section appears to rise faster than the purely hadronic ones (proton-proton and proton-antiproton).

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Large rapidity gaps survival probabilities at LHC

We calculate the probability of large rapidity gaps in high energy hadronic collisions using a model based on QCD mini-jets and soft gluon emission down into the infrared region. Comparing with other models we find a remarkable agreement among most predictions.

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Probing CP properties of the Higgs Boson via \boldmath{e^+e^-\to t \bar{t}ϕ

One of the main endeavors at future high-energy colliders is the search for the Higgs boson(s) and, once found, the probe of the fundamental properties. In particular, the charge conjugation and parity (CP) quantum numbers have to be determined. We show that these are unambiguously accessible at future $e^+e^-$ colliders through the measurement of the total cross section and the top polarization in associated Higgs production with top quark pairs.

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Determining the CP properties of the Higgs boson

The search and the probe of the fundamental properties of Higgs boson(s) and, in particular, the determination of their charge conjugation and parity (CP) quantum numbers, is one of the main tasks of future high-energy colliders. We demonstrate that the CP properties of a Standard Model-like Higgs particle can be unambiguously assessed by measuring just the total cross section and the top polarization in associated Higgs production with top quark pairs in e+e- collisions.

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CP Studies and Non-Standard Higgs Physics

There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories which go beyond the Standard Model and its minimal, CP-conserving supersymmetric extension: two-Higgs-doublet models and minimal supersymmetric models with CP violation, supersymmetric models with an extra singlet, models with extra gauge groups or Higgs triplets, Little Higgs models, models in extra dimensions, and models with technicolour or other new strong dynamics. For each of these scenarios, this report presents an introduction to the phenomenology, followed by contributions on more detailed theoretical aspects and studies of possible experimental signatures at the LHC and other colliders.

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Total cross sections and soft gluon resummation

We discuss a model for total hadronic and photonic cross-sections which includes hard parton-parton scattering to drive the rise and soft gluon resummation to tame it. Unitarity is ensured by embedding the cross-section in the eikonal formalism. Predictions for LHC and ILC are presented.

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Les Houches Physics at TeV Colliders 2005, Standard Model and Higgs working group: Summary report

This Report summarises the activities of the "SM and Higgs" working group for the Workshop "Physics at TeV Colliders", Les Houches, France, 2-20 May, 2005. On the one hand, we performed a variety of experimental and theoretical studies on standard candles (such as W, Z, and ttbar production), treating them either as proper signals of known physics, or as backgrounds to unknown physics; we also addressed issues relevant to those non-perturbative or semi-perturbative ingredients, such as Parton Density Functions and Underlying Events, whose understanding will be crucial for a proper simulation of the actual events taking place in the detectors. On the other hand, several channels for the production of the Higgs, or involving the Higgs, have been considered in some detail. The report is structured into four main parts. The first one deals with Standard Model physics, except the Higgs. A variety of arguments are treated here, from full simulation of processes constituting a background to Higgs production, to studies of uncertainties due to PDFs and to extrapolations of models for underlying events, from small-$x$ issues to electroweak corrections which may play a role in vector boson physics. The second part of the report treats Higgs physics from the point of view of the signal. In the third part, reviews are presented on the current status of multi-leg, next-to-leading order and of next-to-next-to-leading order QCD computations. Finally, the fourth part deals with the use of Monte Carlos for simulation of LHC physics.

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Les Houches "Physics at TeV Colliders 2005'' Beyond the Standard Model working group: summary report

The work contained herein constitutes a report of the "Beyond the Standard Model'' working group for the Workshop "Physics at TeV Colliders", Les Houches, France, 2-20 May, 2005. We present reviews of current topics as well as original research carried out for the workshop. Supersymmetric and non-supersymmetric models are studied, as well as computational tools designed in order to facilitate their phenomenology.

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Supersymmetry Parameter Analysis: SPA Convention and Project

High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e+e- linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.

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Soft gluon radiation and energy dependence of total hadronic cross-sections

An impact parameter representation for soft gluon radiation is applied to obtain both the initial decrease of the total cross-section ($σ_{tot}$) for proton-proton collisions as well as the later rise of $σ_{tot}$ with energy for both $pp$ and $p\bar{p}$. The non-perturbative soft part of the eikonal includes only limited low energy gluon emission and leads to the initial decrease in the proton-proton cross- section. On the other hand, the rapid rise in the hard, perturbative jet part of the eikonal is tamed into the experimentally observed mild increase by soft gluon radiation whose maximum energy rises slowly with energy.

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