Sökresultat

We present a new model, based on color rearrangements, which at the same time can describe both hidden and open charm production in B-meson decays. The model is successfully compared to both inclusive decays, such as B→J/ψX and B→DsX, as well as exclusive ones, such as B→J/ψK(*) and B→D(*)D(*)K. It also gives a good description of the momentum distribution of direct J/ψ's, especially in the low-mo

The quark-gluon plasma (QGP) can be explored in relativistic heavy ion collisions by the jet quenching signature, i.e., by the energy loss of a high energy quark or gluon traversing the plasma. We introduce a novel QCD evolution formalism in the leading logarithm approximation, where normal parton radiation is interleaved with scattering on the plasma gluons occuring at a similar time scale. The i

We investigate the effects of an all order QCD resummation of soft gluon emissions for Higgs boson production in association with two hard jets. We consider both the gluon-gluon fusion and weak boson fusion processes and show how to resum a large part of the leading logarithms in the jet veto scale. Our resummation improves on previous analyses which also aim to include the effects of multiple sof

To properly discover a charged Higgs Boson (H) requires its spin and couplings to be determined. We investigate how to utilize t spin correlations to analyze the H couplings in the decay t bH + bτ + ν τ . Within the framework of a general Two-Higgs-Doublet Model, we obtain results on the spin analyzing coefficients for this decay and study in detail its spin phenomenology, focusing on the limi

Higgs boson production in association with a high pT photon at the CERN Large Hadron Collider is analyzed, in the framework of the MSSM model, for the heavier neutral Higgs bosons. The request of an additional photon in the exclusive Higgs boson final state selects b-quark pairs among the possible initial partonic states, since gluon-gluon initial states are not allowed by C-parity conservation. H

We report on detailed Monte Carlo comparisons of selection variables to separate tbH± signal events from the standard model tt background using an iterative discriminant analysis (IDA) method. While kinematic differences exist between the two processes whenever m_{Hpm≠}m_Wpm , the exploration of the spin difference between the charged Higgs and the W± gauge boson becomes crucial in the particularl

We investigate the viability of observing charged Higgs bosons ( H± ) produced in association with W bosons at the CERN large hadron collider, using the leptonic decay H+ → + ν τ and hadronic W decay, within different scenarios of the minimal supersymmetric standard model (MSSM) with both real and complex parameters. Performing a parton level study we show how the irreducible standard model backgr

At the Large Hadron Collider, we prove the feasibility to detect pair production of the lightest CP-even Higgs boson h of Type II 2-Higgs Doublet Models through qq (′) qq (′)hh (vector-boson fusion). We also show that, through the hh 4b decay channel in presence of heavy-flavour tagging, further exploiting forward/backward jet sampling, one has direct access to the λ Hhh triple Higgs coupling - wh

We show that partons traversing a quark-gluon plasma can lose substantial amounts of energy also by scatterings, and not only through medium-induced radiation as mainly considered previously. Results from Monte Carlo simulations of soft interactions of partons, emerging from a hard scattering, through multiple elastic scatterings on gluons in an expanding relativistic plasma show a sizeable jet qu

Charged Higgs boson production in association with a top quark could be the first indication of the existence of Higgs particles. The Tevatron Run-II started data-taking in April 2001 at √s = 1960 GeV and could probe the existence of a charged Higgs boson beyond the current mass limit. We study the pp̄ → tbH± production process with Monte Carlo simulations in HERWIG and PYTHIA, comparing expected

We study the process gg → bb̄H+H- at large tanβ, where it represents the dominant production mode of charged Higgs boson pairs in a Type II 2-Higgs doublet model, including the minimal supersymmetric standard model. The ability to select this signal would in principle enable the measurements of some triple-Higgs couplings, which in turn would help understanding the structure of the extended Higgs

The interaction potential V(Q2) between static test charges can be used to define an effective charge αv(Q2) and a physically based renormalization scheme for quantum chromodynamics and other gauge theories. In this paper we use recent results for finite-mass fermionic corrections to the heavy-quark potential at two loops to derive the next-to-Ieading order term for the Gell-Mann-Low function of t

A new model for hadronic string reinteractions based on a generalised area law is presented. The model describes both the hadronic final states in e+ e- annihilation and the diffractive structure function in deep inelastic scattering. The model also predicts a shift in the W-mass reconstructed from hadronic decays of W-pairs of the order 65 MeV.

We show that the asymmetry in the fractional energy of charm versus anticharm jets produced in high energy diffractive photoproduction is sensitive to the interference of the Odderon (C=-) and Pomeron (C=+) exchange amplitudes in QCD. We predict the dynamical shape of the asymmetry in a simple model and estimate its magnitude to be of the order 15% using an Odderon coupling to the proton which sat