4,753 research outputs found
Effects of QCD Resummation on and Production at the Tevatron
The resummation of multiple soft gluon emission affects the production rate
and kinematic distributions of (where h is a Higgs boson) and
pairs at the Tevatron with TeV. Using the Collins-Soper-Sterman
resummation formalism, the production rate is enhanced over the
next-to-leading-order (NLO) prediction by 2-3% for the process, for
Higgs boson masses between 80-120 GeV, and over 3% for the process
for GeV. After resummation, the rate changes by 12-13% when
is varied by GeV. Various kinematic distributions are presented
for the individual final state particles and for the pair. The explicit
radiation of hard gluons in NLO QCD is included also for the final
state.Comment: 9 pages, 12 Postscript figures, in RevTeX format, uses epsf.te
The complementarity of LEP, the Tevatron and the LHC in the search for a light MSSM Higgs boson
We study the properties of the Higgs boson sector in the MSSM, putting
special emphasis on radiative effects which can affect the discovery potential
of the LHC, Tevatron and/or LEP colliders. We concentrate on the V b b-bar
channel, with V=Z or W, and on the channels with diphoton final states, which
are the dominant ones for the search for a light Standard Model Higgs boson at
LEP/Tevatron and LHC, respectively. By analyzing the regions of parameter space
for which the searches in at least one of these colliders can be particularly
difficult, we demonstrate the complementarity of these three colliders in the
search for a light Higgs boson which couples in a relevant way to the W and Z
gauge bosons (and hence plays a relevant role in the mechanism of electroweak
symmetry breaking).Comment: 35 pages, including 11 Postscript figures, using JHEP.cl
Matching parton showers to NLO computations
We give a prescription for attaching parton showers to next-to-leading order
(NLO) partonic jet cross sections in electron-positron annihilation. Our method
effectively extends to NLO the scheme of Catani, Krauss, Kuhn, and Webber for
matching between m hard jets and (m+1) hard jets. The matching between parton
splitting as part of a shower and parton splitting as part of NLO matrix
elements is based on the Catani-Seymour dipole subtraction method that is
commonly used for removing the singularities from the NLO matrix elements.}Comment: 45 pages, new introduction, more detailed discussion of the Sudakov
reweightin
Detecting a Light Stop from Top Decays at the Tevatron
We study the possibility of discovering or excluding a light top squark
(stop) based on top quark decays in the t-tbar events produced at the Fermilab
Tevatron. In particular, we consider the Minimal Supersymmetric Standard Model
with the sparticle spectrum m_{chi^+_1}+m_b, M_W+m_{chi^0_1}+m_b > m_{stop} >
m_{chi^0_1}+m_c, where chi^0_1 is the lightest neutralino and chi^+_1 is the
lightest chargino, so that t -> stop chi^0_1 and stop -> c chi^0_1. All other
sparticle masses are assumed to be heavier than m_t. Such a spectrum seeks to
explain the experimental values of alpha_s(M_Z^2), R_b and A_{LR} obtained from
LEP/SLC data. We find that the prospect to observe a light stop via this
channel at the Tevatron is very promising.Comment: 12 pages with 1 Postscript figure using psfig.sty. Postscript file
available at http://sgi2.hep.anl.gov:8001/index.htm
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