5,871 research outputs found
Searches for SUSY at LHC
One of the main motivations of experiments at the LHC is to search for SUSY
particles. The talk is based on recent analyses, performed by CMS
Collaboration, within the framework of the Supergravity motivated minimal SUSY
extension of the Standard Model. The emphasis is put on leptonic channels. The
strategies for obtaining experimental signatures for strongly and weakly
interacting sparticles productions, as well as examples of determination of
SUSY masses and model parameters are discussed. The domain of parameter space
where SUSY can be discovered is investigated. Results show, that if SUSY is of
relevance at Electro-Weak scale it could hardly escape detection at LHC.Comment: LaTeX, 6 pages, 8 eps figures. Presented at XXXII Rencontres de
Moriond: QCD and High Energy Hadronic Interactions, Les Arcs, Savoie, France,
March 22-29, 199
Polarization at HERA-
The production of mesons in fixed target collisions is
considered. It is shown that Non-Relativistic QCD predicts states to
be produced with sizeable transverse polarization. The possibility of a
measurement of the polarization at the HERA- experiment is
discussed.Comment: 9 pages, LaTeX, with 3 eps figs included with epsfig.st
Top Mass Determination in Leptonic Final States with
Taking advantage of large top production rates at the LHC, the leptonic final states with J/psi are explored for a precise determination of the top quark mass. The top is partially reconstructed by combining the isolated lepton from the W with the J/psi from the decays of the corresponding b-quark. The method relies, to a large extent, on the proper Monte-Carlo description of top production and decay. The main emphasis is put on the expected systematics uncertainties. Mass measurement accuracy is dominated by the current understanding of theoretical uncertainties which result in a systematic error of <~1 GeV
Search for the next-to-lightest neutralino
We study the inclusive production of the next-to-lightest neutralino chi2,
decaying directly, or via slepton, into two leptons and the lightest
neutralino. The dilepton invariant mass spectrum in these decays has a
characteristic sharp edge near the kinematical upper limit. We propose to
exploit this feature as a search strategy for the chi2, and thereby for SUSY.
The possibilities to determine neutralinos and slepton masses are also
discussed.Comment: LaTeX, 10 pages, 7 eps figures; submitted to Nuclear Physics B; a
more detailed version is available under
ftp://cmsdoc.cern.ch/documents/97/note97_065.ps.
Corporate Governance in Companies with State Participation
In modern conditions the ongoing development of corporate governance in our country due to several factors. First of all, the Russian economy is increasingly involved in the economic processes of globalization, increased interaction of large Russian companies with the global financial market. In addition, Russia’s largest company significantly expanded its international activities, including through the acquisition of foreign assets. Joint-stock medium-sized companies have realized the need to attract external financing through the search for a strategic investor or access to stock markets. Significant changes made to the corporate legislation
The Presampler for the Forward and Rear Calorimeter in the ZEUS Detector
The ZEUS detector at HERA has been supplemented with a presampler detector in
front of the forward and rear calorimeters. It consists of a segmented
scintillator array read out with wavelength-shifting fibers. We discuss its
desi gn, construction and performance. Test beam data obtained with a prototype
presampler and the ZEUS prototype calorimeter demonstrate the main function of
this detector, i.e. the correction for the energy lost by an electron
interacting in inactive material in front of the calorimeter.Comment: 20 pages including 16 figure
Color Octet Contribution to J/psi Photoproduction Asymmetries
We investigate photoproduction asymmetries in the framework of the
NRQCD factorization approach. It is shown that the color octet contribution
leads to large uncertainties in the predicted asymmetries which rules out the
possibility to precisely measure the gluon polarization in the nucleon through
this final state. For small values of the color octet parameters being
compatible with photoproduction data it appears possible that a
measurement of asymmetries could provide a new test for the NRQCD
factorization approach, on one hand, or a measurement of the polarized gluon
distribution from low inelasticity events , on the otherComment: 12 pages, LaTeX, with 6 figs. Final version published in Phys.Rev.
Bottom Production
We review the prospects for bottom production physics at the LHC.Comment: 74 pages, Latex, 71 figures, to appear in the Report of the ``1999
CERN Workshop on SM physics (and more) at the LHC'', P. Nason, G. Ridolfi, O.
Schneider G.F. Tartarelli, P. Vikas (conveners
NLO QCD corrections to off-shell top-antitop production with leptonic decays at hadron colliders
We present details of a calculation of the cross section for hadronic
top-antitop production in next-to-leading order (NLO) QCD, including the decays
of the top and antitop into bottom quarks and leptons. This calculation is
based on matrix elements for \nu e e+ \mu- \bar{\nu}_{\mu}b\bar{b} production
and includes all non-resonant diagrams, interferences, and off-shell effects of
the top quarks. Such contributions are formally suppressed by the top-quark
width and turn out to be small in the inclusive cross section. However, they
can be strongly enhanced in exclusive observables that play an important role
in Higgs and new-physics searches. Also non-resonant and off-shell effects due
to the finite W-boson width are investigated in detail, but their impact is
much smaller than naively expected. We also introduce a matching approach to
improve NLO calculations involving intermediate unstable particles. Using a
fixed QCD scale leads to perturbative instabilities in the high-energy tails of
distributions, but an appropriate dynamical scale stabilises NLO predictions.
Numerical results for the total cross section, several distributions, and
asymmetries are presented for Tevatron and the LHC at 7 TeV, 8 TeV, and 14 TeV.Comment: 61 pp. Matches version published in JHEP; one more reference adde
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