Search

Higgs production in association with a $W$ boson and two energetic tag jets at the LHC is studied for $M_H = 120$ \GeV, with the Higgs decaying to $b\bar{b}$ and the $W$ to $\ell��$ ($\ell = e, ��$), guaranteeing high trigger efficiency. All parton level backgrounds are analyzed, including the effect of fake $b$--tagging. We discuss two detection strategies: in the first, more traditional, one, two jets are required to be $b$--tagged while in the second, which has not been previously examined in detail, only one tag is required. After all selection cuts about 80 and 200 events are foreseen in the two cases for a standard luminosity of 100 $fb^{-1}$ with a S/B ratio of 1/25 and 1/60 respectively. The corresponding statistical significancies, S/$\sqrt{\mathrm B}$ are 1.81 and 1.82., Version accepted for publication in JHEP. Improved analysis of double b-tagging case. Brief discussion of prospects at the SLHC added

Helicity amplitudes calculations with the program PHACT are explained. Some examples of their application in WPHACT and SIXPHACT MC's are given., 7 pages, 2 figs. Talk given at QFTHEP'99 Workshop Moscow, Russia, May 27 - June 2 1999. To be published in the proceedings

We review some recent results and open problems on four fermion physics at LEP2 and beyond, 5 pages, 5 figures. Invited talk given at the EPS Conference on High Energy Physics. Tampere, Finland, July 1999 - To appear in the Proceedings

We review some features and results of the calculations performed with the program SIXPHACT for six fermion final states at Linear Collider, Presented at the Zeuthen Workshop on Elementary Particle Physics - Loops and Legs in Gauge Theories - Rheinsberg, 19--24 April 1998 8 pages, 4 ps figures, uses epsfig,appb2,axodraw

We compute several total and differential cross sections relevant to top, WWZ and Higgs physics at future $e^+e^-$ colliders taking into account the full set of Feynman diagrams for six fermion final states. We examine in particular charged current processes, in which final particles cannot be formed by three Z's decay. We include in our calculations initial state radiation and beamstrahlung effects, and the most important QCD corrections in an approximate (naive) form. We also compare this complete approach with production $\times$ decay approximation., Comment: Latex, 16 pages, 8 ps figures included; to appear in the Proceedings of the "Joint ECFA/DESY Study on Physics and Detectors for the Linear Collider", February to November 1996, ed. R. Settles, Desy 97-123E

WPHACT (W W and Higgs Physics with PHACT) is a MC program and unweighted event generator which computes all Standard Model processes with four fermion in the final state at $e^+ e^-$ colliders. It is based on an helicity amplitude method which allows precise and fast evaluations of the matrix elements both for massless and massive fermions. Fermion masses for $b$ quarks are exactly taken into account. QED initial state and Coulomb corrections are evaluated, while QCD final state corrections are included in an approximate formulation. Cuts can be easily introduced and distributions for any variable at parton level can be implemented. The contributions to the processes of neutral Standard Model or Susy Higgs can be included. Anomalous couplings effects for the triple coupling can be computed. An interface to hadronization is provided and Jetset can be directly called from the program., Comment: 35 pages + 2 ps figures

An helicity formalism for perturbative calculations is presented. It is based on the formal insertion in spinor lines of a complete set of states built up with unphysical spinors. It is particularly convenient when massive spinors are present. Its application to $e^+\,e^-\,\rightarrow b\,\bar b\,W^+W^-$ is briefly discussed., To appear in Proceedings Nonlinear Phenomena in Complex Systems. Polatsk Belarus. February 94 - 8 pages, 2 figs. using feynman.tex

Heavy quark production in multijet events at $e^+e^-$ colliders is studied at tree level. Total production rates are given and compared with the corresponding results for massless quarks. A new method of computing helicity amplitudes is briefly sketched. Talk presented at the XXIXth Rencontres de Moriond, QCD and High Energy Hadronic Interactions, Meribel, France, March 19-26 1994., Comment: LateX, 6 pag + 2 figs uucompressed

We analyse some features of WW scattering processes at LHC. The severe cancellations between fusion diagrams and the other contributions evidence the necessity of complete calculations for studying the high WW invariant mass region and disentangling the standard Higgs case from new physics., To appear in Proceedings of the XVIII Workshop onQuantum Field Theory and High Energy Physics (QFTHEP04) - St. Petersburg June 2004

This document summarises the talks and discussions happened during the VBSCan Mid-Term Scientific Meeting workshop. The VBSCan COST action is dedicated to the coordinated study of vector boson scattering (VBS) from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders., Editors: I.Brivio, C.Charlot, R.Covarelli, R.L.Delgado, K.Lohwasser, M.Pellen, M.Slawinska, G.Ortona, K.Ozdemir, C.Petridou, I.Puljak, M.Zaro. Proceedings for the VBSCan Mid-Term Scientific Meeting of the VBSCan COST action