7 research outputs found
The automatic computation for SUSY processes
We have constructed a system for the automatic computation of cross-sections
for the processes of the SUSY QED by the extension of the GRACE system
including a Majorana fermion. The system has also been applied to another model
including Majorana fermions, MSSM, by the definition of the model file.Comment: total 4 page
PHASE, a Monte Carlo event generator for six-fermion physics at the LHC
PHASE is a new event generator dedicated to the study of Standard Model
processes with six fermions in the final state at the LHC. The code is intended
for analyses of vector boson scattering, Higgs search, three gauge boson
production, and top physics. This first version of the program describes final
states characterized by the presence of one neutrino, , at
O(). PHASE is based on a new iterative-adaptive multichannel
technique, and employs exact leading order matrix elements. The code can
generate unweighted events for any subset of all available final states. The
produced parton-level events carry full information on their colour and flavour
structure, enabling the evolution of the partons into fully hadronised final
states. An interface to hadronization packages is provided via the Les Houches
Protocol.Comment: 27 pages, Latex, 6 figure
signals at LEP2 energies in the Minimal Supersymmetric Standard Model
In this paper we compare and into four-fermion production
at centre-of-mass energies typical of LEP2 and somewhat larger. The theoretical
framework considered is the Minimal Supersymmetric Standard Model. The interest
in exploiting the CERN collider at values of greater than
192 GeV could come from the discovery of Supersymmetric signals during runs at
lower energy. If these indicate that a charged Higgs boson exists in the mass
range \MH\approx95-105 GeV, then a few years of running at
GeV and nominal luminosity could make the detection of such scalars feasible,
in the purely leptonic channel and, for small
\tb's, also in the semi-hadronic(leptonic) one . Charged
Higgs bosons of the above nature cannot be produced by the beam energies
approved at present for LEP2. However, if runs beyond the so-called `192 GeV
cryogenic limit' will be approved by the CERN Council, our selection procedure
will enable us to establish the presence, or otherwise, of charged Higgs bosons
in the mentioned mass rangeComment: 30 pages, latex, epsfig, 12 postscript figures, complete paper
available at ftp://axpa.hep.phy.cam.ac.uk/stefano/cavendish_9615 and at
http://www.hep.phy.cam.ac.uk/theory/papers
ALPGEN, a generator for hard multiparton processes in hadronic collisions
This paper presents a new event generator, ALPGEN, dedicated to the study of
multiparton hard processes in hadronic collisions. The code performs, at the
leading order in QCD and EW interactions, the calculation of the exact matrix
elements for a large set of parton-level processes of interest in the study of
the Tevatron and LHC data. The current version of the code describes the
following final states: (W -> ffbar') QQbar+ N jets (Q being a heavy quark, and
f=l,q), with N f fbar)+QQbar+Njets (f=l,nu), with N
ffbar') + charm + N jets (f=l,q), N f fbar') + N jets (f=l,q) and
(Z/gamma* -> f fbar)+ N jets (f=l,nu), with N<=6; nW+mZ+lH+N jets, with
n+m+l+N<=8 and N<=3 including all 2-fermion decay modes of W and Z bosons, with
spin correlations; Q Qbar+N jets (N b f fbar' decays and relative
spin correlations included if Q=t; Q Qbar Q' Qbar'+N jets, with Q and Q' heavy
quarks (possibly equal) and N b f fbar'
decays and relative spin correlations included if Q=t; N jets, with N<=6.
Parton-level events are generated, providing full information on their colour
and flavour structure, enabling the evolution of the partons into fully
hadronised final states.Comment: 1+38 pages, uses JHEP.cls. Documents code version 1.2: extended list
of processes, updated documentation and bibliograph
Standard Model Large-E_T Processes and Searches for New Physics at HERA
Existing and missing calculations of standard model processes producing large
transverse energy in electron-proton interactions at HERA are reviewed. The
adequacy of the existing standard model Monte Carlo programs for generic
searches of exotic processes is analyzed.Comment: 9 pages, LaTeX, uses iop style files, Contribution to the 3rd UK
Phenomenology Workshop on HERA Physics, September 1998, Durha