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F. Charles

Publications and source records attributed to F. Charles.

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The Beyond the Standard Model Working Group: Summary Report

Report of the "Beyond the Standard Model" working group for the Workshop `Physics at TeV Colliders', Les Houches, France, 21 May - 1 June 2001. It consists of 18 separate parts: 1. Preface; 2. Theoretical Discussion; 3. Numerical Calculation of the mSUGRA and Higgs Spectrum; 4. Theoretical Uncertainties in Sparticle Mass Predictions; 5. High Mass Supersymmetry with High Energy Hadron Colliders; 6. SUSY with Heavy Scalars at LHC; 7. Inclusive Study of MSSM in CMS; 8. Establishing a No-Lose Theorem for NMSSM Higgs Boson Discovery at the LHC; 9. Effects of Supersymmetric Phases on Higgs Production in Association with Squark Pairs in the Minimal Supersymmetric Standard Model; 10. Study of the Lepton Flavour Violating Decays of Charged Fermions in SUSY GUTs; 11. Interactions of the Goldstino Supermultiplet with Standard Model Fields; 12. Attempts at Explaining the NuTeV Observation of Di-Muon Events; 13. Kaluza-Klein States of the Standard Model Gauge Bosons: Constraints From High Energy Experiments; 14. Kaluza-Klein Excitations of Gauge Bosons in the ATLAS Detector; 15. Search for the Randall Sundrum Radion Using the ATLAS Detector; 16. Radion Mixing Effects on the Properties of the Standard Model Higgs Boson; 17. Probing Universal Extra Dimensions at Present and Future Colliders; 18. Black Hole Production at Future Colliders.

hep-ph

Higgs and Supersymmetry searches at the Large Hadron Collider

We present here the results for Higgs and Supersymmetry prospective searches at the Large Hadron Collider. We show that for one year at high luminosity, Standard Model and MSSM Higgs should be observed within the theoretically expected mass range. MSUGRA and restricted phenomenological MSSM searches lead to discovery of up to 2.5 TeV squarks and gluinos.

hep-ph

Study of leptoquark pair production at the LHC with the CMS detector

We study the discovery potential of the CMS detector for the scalar leptoquark pair production at the LHC. Present and future exclusion limits are considered. We find that the maximal leptoquark mass reach is about 1.47 TeV for the branching ratio of Br(LQ_l -> l q)=100 %, while for Br(LQ_l -> l q)=50 % the upper limit is 1.2 TeV for an integrated luminosity of 100 fb-1. We obtain comparable results for electron and muon-type leptoquarks. The pileup effect at high luminosity is discussed.

hep-ph

Search for SUSY in (Leptons +) Jets + E_T^miss final states

We study the observability of the squarks and gluinos in CMS at LHC. Classical E_T^miss + jets final state as well as a number of additional multilepton signatures (0 leptons, 1 lepton, 2 leptons of the same sign, 2 leptons of the opposite sign and 3 leptons) are investigated . The detection of these sparticles relies on the observation of an excess of events over Standard Model background expectations. The study is made in the framework of a minimal SU(5) mSUGRA model as a function of m_0, m_1/2 for 4 sets of model parameters : tan(beta) = 2 or 35 and sign(mu) = +/- 1 and for fixed value of A_0 = 0. The CMS detector response is modelled using CMSJET 4.51 fast MC code (non-GEANT). The results obtained are presented as 5 sigma detection contours in the m_0, m_1/2 planes and with optimized selection cuts in various regions of the parameter space. The result of these investigations is that with integrated luminosity L=10^5 pb^-1 the squark and gluino mass reach is about 2.5 TeV and covers most of the interesting parts of parameter space according to neutralino relic density expectations. The influence of signal and background cross-section uncertainties on the reach contours is estimated. The effect of pile-up on signal and background is also discussed. This effect is found to be insignificant for E_T^miss and single lepton signatures, whilst only a minor deterioration is seen for multilepton final states.

hep-ph

Report of the GDR working group on the R-parity violation

This report summarizes the work of the "R-parity violation group" of the French Research Network (GDR) in Supersymmetry, concerning the physics of supersymmetric models without conservation of R-parity at HERA, LEP, Tevatron and LHC and limits on R-parity violating couplings from various processes. The report includes a discussion of the recent searches at the HERA experiment, prospects for new experiments, a review of the existing limits, and also theoretically motivated alternatives to R-parity and a brief discussion on the implications of R-parity violation on the neutrino masses.

hep-ph

Discovery potential for supersymmetry in CMS

This work summarizes and puts in an overall perspective studies done within CMS concerning the discovery potential for squarks and gluinos, sleptons, charginos and neutralinos, SUSY dark matter, lightest Higgs, sparticle mass determination methods and the detector design optimisation in view of SUSY searches. It represents the status of our understanding of these subjects as of Summer 1997. As a benchmark model we used the minimal supergravity-inspired super- symmetric standard model (mSUGRA) with a stable LSP. Discovery of SUSY at the LHC should be relatively straightforward. It may occur through the observation of a large excesses of events in missing E_T + jets, or with one or more isolated leptons. An excess of trilepton events or of isolated dileptons with E_T^miss, exhibiting a characteristic signature in the l^+l^- invariant mass distribution could also be the first manifestation of SUSY production. Squark and gluino production may represent a copious source of Higgs bosons through cascade decays. The lightest SUSY Higgs h->bbbar may be reconstructed with a signal/background ratio of order 1. The lightest supersymmetric particle of SUSY models with conserved R-parity represents a very good candidate for the cosmological dark matter. The region of parameter space where this is true is well-covered by our searches, at least for tan(beta)=2. If supersymmetry exists at electroweak scale it could hardly escape detection in CMS, and the study of supersymmetry will form a central part of our physics program.

hep-ph