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Title: Technicolor contribution to lepton+photon+Ee{sub T} events at the Fermilab Tevatron

Abstract

Events with one lepton, one photon, and missing energy are the subject of recent searches at the Fermilab Tevatron. We compute possible contributions to these types of events from the process pp{yields}{gamma}l{nu}{sub l}{nu}{sub {tau}}{nu}{sub {tau}}, where l=e, {mu} in the context of a low scale technicolor model. We find that with somewhat tighter cuts than the ones used in the CDF search, it could be possible to either confirm or exclude this model in a small region of its parameter space.

Authors:
; ;  [1];  [2];  [3]
  1. Instituto de Fisica, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia (Chile)
  2. (Chile)
  3. (Brazil)
Publication Date:
OSTI Identifier:
21020524
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 9; Other Information: DOI: 10.1103/PhysRevD.75.097702; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COLOR MODEL; FERMILAB COLLIDER DETECTOR; FERMILAB TEVATRON; LEPTONS; NEUTRINOS; PHOTONS; PROTON-PROTON INTERACTIONS; SPACE; TRANSVERSE ENERGY

Citation Formats

Zerwekh, Alfonso R., Dib, Claudio O., Rosenfeld, Rogerio, Department of Physics, Universidad Tecnica Federico Santa Maria, Valparaiso, and Instituto de Fisica Teorica-Sao Paulo State University, Rua Pamplona, 145, 01405-900, Sao Paulo, SP. Technicolor contribution to lepton+photon+Ee{sub T} events at the Fermilab Tevatron. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.097702.
Zerwekh, Alfonso R., Dib, Claudio O., Rosenfeld, Rogerio, Department of Physics, Universidad Tecnica Federico Santa Maria, Valparaiso, & Instituto de Fisica Teorica-Sao Paulo State University, Rua Pamplona, 145, 01405-900, Sao Paulo, SP. Technicolor contribution to lepton+photon+Ee{sub T} events at the Fermilab Tevatron. United States. doi:10.1103/PHYSREVD.75.097702.
Zerwekh, Alfonso R., Dib, Claudio O., Rosenfeld, Rogerio, Department of Physics, Universidad Tecnica Federico Santa Maria, Valparaiso, and Instituto de Fisica Teorica-Sao Paulo State University, Rua Pamplona, 145, 01405-900, Sao Paulo, SP. Tue . "Technicolor contribution to lepton+photon+Ee{sub T} events at the Fermilab Tevatron". United States. doi:10.1103/PHYSREVD.75.097702.
@article{osti_21020524,
title = {Technicolor contribution to lepton+photon+Ee{sub T} events at the Fermilab Tevatron},
author = {Zerwekh, Alfonso R. and Dib, Claudio O. and Rosenfeld, Rogerio and Department of Physics, Universidad Tecnica Federico Santa Maria, Valparaiso and Instituto de Fisica Teorica-Sao Paulo State University, Rua Pamplona, 145, 01405-900, Sao Paulo, SP},
abstractNote = {Events with one lepton, one photon, and missing energy are the subject of recent searches at the Fermilab Tevatron. We compute possible contributions to these types of events from the process pp{yields}{gamma}l{nu}{sub l}{nu}{sub {tau}}{nu}{sub {tau}}, where l=e, {mu} in the context of a low scale technicolor model. We find that with somewhat tighter cuts than the ones used in the CDF search, it could be possible to either confirm or exclude this model in a small region of its parameter space.},
doi = {10.1103/PHYSREVD.75.097702},
journal = {Physical Review. D, Particles Fields},
number = 9,
volume = 75,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}
  • If the technicolor {omega}{sub T} particle exists, a likely decay mode is {omega}{sub T}{r_arrow}{gamma}{pi}{sub T} , followed by {pi}{sub T}{r_arrow}b{bar b} , yielding the signature {gamma}b{bar b} . We have searched 85 pb{sup {minus}1} of data collected by the CDF experiment at the Fermilab Tevatron for events with a photon and two jets, where one of the jets must contain a secondary vertex implying the presence of a b quark. We find no excess of events above standard model expectations. We express the result as an exclusion region in the M{sub {omega}{sub T}}-M{sub {pi}{sub T}} mass plane. {copyright} {ital 1999}more » {ital The American Physical Society }« less
  • If the technicolor [omega][sub T] particle exists, a likely decay mode is [omega][sub T][r arrow][gamma][pi][sub T] , followed by [pi][sub T][r arrow]b[bar b] , yielding the signature [gamma]b[bar b] . We have searched 85 pb[sup [minus]1] of data collected by the CDF experiment at the Fermilab Tevatron for events with a photon and two jets, where one of the jets must contain a secondary vertex implying the presence of a b quark. We find no excess of events above standard model expectations. We express the result as an exclusion region in the M[sub [omega][sub T]]-M[sub [pi][sub T]] mass plane. [copyright]more » [ital 1999] [ital The American Physical Society ]« less
  • A search for new physics using three-lepton (trilepton) data collected with the CDF II detector and corresponding to an integrated luminosity of 976 pb{sup -1} is presented. The standard model predicts a low rate of trilepton events, which makes some supersymmetric processes, such as chargino-neutralino production, measurable in this channel. The {mu}{mu}+l signature is investigated, where l is an electron or a muon, with the additional requirement of large missing transverse energy. In this analysis, the lepton transverse momenta with respect to the beam direction (p{sub T}) are as low as 5 GeV/c, a selection that improves the sensitivity tomore » particles that are light as well as to ones that result in leptonically decaying tau leptons. At the same time, this low-p{sub T} selection presents additional challenges due to the non-negligible heavy-quark background at low lepton momenta. This background is measured with an innovative technique using experimental data. Several dimuon and trilepton control regions are investigated, and good agreement between experimental results and standard-model predictions is observed. In the signal region, we observe one three-muon event and expect 0.4{+-}0.1 {mu}{mu}+l events from standard-model processes.« less
  • We study the contributions of the neutral pseudo Goldstone bosons (technipions and top pions) to the t{bar t} production cross sections at the Fermilab Tevatron and the CERN LHC in top-color-assisted multiscale technicolor (TOPCMTC) models via the gluon-gluon fusion process from the loop-level couplings between the pseudo Goldstone bosons and the gluons. The MRS set A{sup {prime}} parton distributions are used in the calculation. It is shown that the new CDF datum on the t{bar t} production cross section gives constraints on the parameters in the TOPCMTC models. Models with a large portion of technicolor contributed top-quark mass are disfavored.more » With reasonable values of the parameters in TOPCMTC models, the cross section at the Tevatron is larger than that predicted by the standard model, and is consistent with the new CDF data. The enhancement of the cross section and the resonance peaks at the LHC are more significant, so that it is testable in future experiments. {copyright} {ital 1997} {ital The American Physical Society}« less
  • We examine the processes {ital p{bar p}}{r arrow}{ital {tilde g}{tilde g}}, {ital {tilde q}{tilde g}}, and {ital {tilde q}{tilde q}} at Fermilab Tevatron collider energies and find an observable signal for {ital Z}{sup 0}+{ge}2 jets+missing {ital p}{sub {ital T}} events due to cascade and loop decays of squarks and gluinos. This signal occurs in a substantial region of the supersymmetric parameter space provided only that the Higgsino-mixing mass parameter is small. We evaluate several different standard-model backgrounds, and show that the signal (which can yield up to 25 events in the next Tevatron run) exceeds background for {ital m}{sub {italmore » {tilde q}}} or {ital m}{sub {ital {tilde g}}} as large as 200 GeV. Distributions which discriminate the supersymmetric signal from background are also shown.« less