gg -> h -> tau(+)tau(-) at the upgraded Fermilab Tevatron

We study the neutral Higgs boson production via the gluon fusion process with the tau(+)tau(-) final state at the upgraded Fermilab Tevatron, including a complete simulation of signal channels and leading background processes. For the SM Higgs boson, this h --> tau(+)tau(-) channel may provide important addition for the Higgs boson discovery in the mass range 120 - 140 GeV. In minimal supersymmetric models, natural enhancement for the signal rate over the SM expectation makes the h, H, A --> tau(+)tau(-) signal observable for large tan beta and low MA, which may lead to full coverage for SUSY Higgs parameters at the Tevatron with a moderate integrated luminosity.

Search for R-parity violating supersymmetry via the LL(E)over-bar couplings lambda(121), lambda(122) or lambda(133) in p(p)over-bar collisions at root s=1.96 TeV

A search for gaugino pair production with a trilepton signature in the framework of R-parity violating supersymmetry via the couplings; lambda(121), lambda(122), or lambda(133) is presented. The data, corresponding to an integrated luminosity of L approximate to 360 pb(-1), were collected from April 2002 to August 2004 with the D0 detector at the Fermilab Tevatron Collider, at a center-of-mass energy of root s = 1.96 TeV. This analysis considers final states with three charged leptons with the flavor combinations eel, mu mu l, and ee tau (l = e or mu). No evidence for supersymmetry is found and limits at the 95% confidence level are set on the gaugino pair production cross section and lower bounds on the masses of the lightest neutralino and chargino are derived in two supersymmetric models. (c) 2006 Elsevier B.V. All rights reserved.

Heavy-flavor tagging and the supersymmetry reach of the CERN Large Hadron Collider

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Search for New Physics with Same-Sign Isolated Dilepton Events with Jets and Missing Transverse Energy

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Supergraph approach in a higher-order linear delta expansion calculation of the effective potential for F-type broken supersymmetry

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Search for electroweak production of charginos and neutralinos using leptonic final states in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Probing neutralino properties in minimal supergravity with bilinear R-parity violation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Signatures of spontaneous breaking of R-parity in gluino cascade decays at LHC

We study the pattern of gluino cascade decays in a class of supersymmetric models where R-parity is spontaneously broken. We give a detailed discussion of the R-parity violating decays of the lightest neutralino, the second lightest neutralino and the lightest chargino. The multi-lepton and same-sign dilepton signal rates expected in these models are compared with those predicted in the Minimal Supersymmetric Standard Model. We show that these rates can be substantially enhanced in broken R-parity models. © 1997 Elsevier Science B.V.

Signals for CP violation in scalar tau pair production at muon colliders

We discuss signals for CP violation in μ + μ - → Τ̃ i - Τ̃ j +, where i, j = 1, 2 label the two scalar Τ mass eigenstates. We assume that these reactions can proceed through the production and decay of the heavy neutral Higgs bosons present in supersymmetric models. CP violation in the Higgs sector can be probed through a rate asymmetry even with unpolarized beams, while the CP-odd phase associated with the Τ̃ mass matrix can be probed only if the polarization of at least one beam can be varied. These asymmetries might be O (1).

Multilepton signatures for leptoquarks

The production of third generation leptoquarks can give rise to multilepton events accompanied by jets and missing ET. In this work we study the signals of these leptoquarks at the CERN Large Hadron Collider and compare them with the ones expected in supersymmetric models. ©1998 The American Physical Society.

R-parity-violating signals for chargino production at LEP II

We study chargino pair production at LEP II in supersymmetric models with spontaneously broken R-parity. We perform signal and background analyses, showing that a large region of the parameter space of these models can be probed through chargino searches at LEP II. In particular, we determine the attainable limits on the chargino mass as a function of the magnitude of the effective bilinear R-parity violation parameter ∈, demonstrating that LEP II is able to unravel the existence of charginos with masses almost up to their kinematical limit even in the case of R-parity violation. This requires the study of several final state topologies since the usual MSSM chargino signature is recovered as ∈ → 0. Moreover, for sufficiently large ∈ values, for which the chargino decay mode χ ± → τ ± J dominates, we find through a dedicated Monte Carlo analysis that the χ ± mass bounds are again very close to the kinematic limit. Our results establish the robustness of the chargino mass limit, in the sense that it is basically model-independent. They also show that LEP II can establish the existence of spontaneous R-parity violation in a large region of parameter space should charginos be produced. © 1999 Elsevier Science B.V.

Gg → h → τ+τ- at the upgraded Fermilab Tevatron

We study the neutral Higgs boson production via the gluon fusion process with the τ+τ- final state at the upgraded Fermilab Tevatron, including a complete simulation of signal channels and leading background processes. For the SM Higgs boson, this h → τ +τ- channel may provide important addition for the Higgs boson discovery in the mass range 120 -140 GeV. In minimal supersymmetric models, natural enhancement for the signal rate over the SM expectation makes the h, H, A → τ+τ- signal observable for large tan β and low MA, which may lead to full coverage for SUSY Higgs parameters at the Tevatron with a moderate integrated luminosity. © SISSA/ISAS 2003.

Search for pair production of third-generation leptoquarks and top squarks in pp collisions at √s=7 TeV

Results are presented from a search for the pair production of third-generation scalar and vector leptoquarks, as well as for top squarks in R-parity-violating supersymmetric models. In either scenario, the new, heavy particle decays into a τ lepton and a b quark. The search is based on a data sample of pp collisions at √s=7 TeV, which is collected by the CMS detector at the LHC and corresponds to an integrated luminosity of 4.8 fb -1. The number of observed events is found to be in agreement with the standard model prediction, and exclusion limits on mass parameters are obtained at the 95% confidence level. Vector leptoquarks with masses below 760 GeV are excluded and, if the branching fraction of the scalar leptoquark decay to a τ lepton and a b quark is assumed to be unity, third-generation scalar leptoquarks with masses below 525 GeV are ruled out. Top squarks with masses below 453 GeV are excluded for a typical benchmark scenario, and limits on the coupling between the top squark, τ lepton, and b quark, λ333′ are obtained. These results are the most stringent for these scenarios to date. © 2013 CERN.

Search for supersymmetry in final states with a single lepton, b-quark jets, and missing transverse energy in proton-proton collisions at √s=7 TeV

A search motivated by supersymmetric models with light top squarks is presented using proton-proton collision data recorded with the CMS detector at a center-of-mass energy of √s=7 TeV during 2011, corresponding to an integrated luminosity of 4.98 fb-1. The analysis is based on final states with a single lepton, b-quark jets, and missing transverse energy. Standard model yields are predicted from data using two different approaches. The observed event numbers are found to be compatible with these predictions. Results are interpreted in the context of the constrained minimal supersymmetric standard model and of a simplified model with four top quarks in the final state. © 2013 CERN.

Search for physics beyond the standard model in events with τ leptons, jets, and large transverse momentum imbalance in pp collisions at √s = 7 TeV

A search for physics beyond the standard model is performed with events having one or more hadronically decaying τ leptons, highly energetic jets, and large transverse momentum imbalance. The data sample corresponds to an integrated luminosity of 4.98 fb-1 of proton-proton collisions at √ = 7 TeV collected with the CMS detector at the LHC in 2011. The number of observed events is consistent with predictions for standard model processes. Lower limits on the mass of the gluino in supersymmetric models are determined. © 2013 CERN for the benefit of the CMS collaboration.