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Title: New results for light gravitinos at hadron colliders: Fermilab Tevatron limits and CERN LHC perspectives

Abstract

We derive Feynman rules for the interactions of a single gravitino with (s)quarks and gluons/gluinos from an effective supergravity Lagrangian in nonderivative form and use them to calculate the hadroproduction cross sections and decay widths of single gravitinos. We confirm the results obtained previously with a derivative Lagrangian as well as those obtained with the nonderivative Lagrangian in the high-energy limit and elaborate on the connection between gauge independence and the presence of quartic vertices. We perform extensive numerical studies of branching ratios, total cross sections, and transverse-momentum spectra at the Fermilab Tevatron and the CERN LHC. From the latest CDF monojet cross section limit, we derive a new and robust exclusion contour in the gravitino-squark/gluino mass plane, implying that gravitinos with masses below 2x10{sup -5} to 1x10{sup -5} eV are excluded for squark/gluino masses below 200 and 500 GeV, respectively. These limits are complementary to the one obtained by the CDF Collaboration, 1.1x10{sup -5} eV, under the assumption of infinitely heavy squarks and gluinos. For the LHC, we conclude that supersymmetric scenarios with light gravitinos will lead to a striking monojet signal very quickly after its startup.

Authors:
;  [1];  [2]
  1. Institut fuer Theoretische Physik, Universitaet Goettingen, Friedrich-Hund-Platz 1, D-37077 Goettingen (Germany) and Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier/CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble (France)
  2. (France)
Publication Date:
OSTI Identifier:
20929565
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 11; Other Information: DOI: 10.1103/PhysRevD.75.115003; (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; BRANCHING RATIO; CERN LHC; FERMILAB COLLIDER DETECTOR; FERMILAB TEVATRON; GEV RANGE 100-1000; GLUONS; GRAVITONS; LAGRANGIAN FUNCTION; MASS; NUMERICAL ANALYSIS; PARTICLE DECAY; PARTICLE WIDTHS; S QUARKS; SIGNALS; SUPERGRAVITY; SUPERSYMMETRY; TOTAL CROSS SECTIONS; TRANSVERSE MOMENTUM

Citation Formats

Klasen, Michael, Pignol, Guillaume, and Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier/CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble. New results for light gravitinos at hadron colliders: Fermilab Tevatron limits and CERN LHC perspectives. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.115003.
Klasen, Michael, Pignol, Guillaume, & Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier/CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble. New results for light gravitinos at hadron colliders: Fermilab Tevatron limits and CERN LHC perspectives. United States. doi:10.1103/PHYSREVD.75.115003.
Klasen, Michael, Pignol, Guillaume, and Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier/CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble. Fri . "New results for light gravitinos at hadron colliders: Fermilab Tevatron limits and CERN LHC perspectives". United States. doi:10.1103/PHYSREVD.75.115003.
@article{osti_20929565,
title = {New results for light gravitinos at hadron colliders: Fermilab Tevatron limits and CERN LHC perspectives},
author = {Klasen, Michael and Pignol, Guillaume and Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier/CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble},
abstractNote = {We derive Feynman rules for the interactions of a single gravitino with (s)quarks and gluons/gluinos from an effective supergravity Lagrangian in nonderivative form and use them to calculate the hadroproduction cross sections and decay widths of single gravitinos. We confirm the results obtained previously with a derivative Lagrangian as well as those obtained with the nonderivative Lagrangian in the high-energy limit and elaborate on the connection between gauge independence and the presence of quartic vertices. We perform extensive numerical studies of branching ratios, total cross sections, and transverse-momentum spectra at the Fermilab Tevatron and the CERN LHC. From the latest CDF monojet cross section limit, we derive a new and robust exclusion contour in the gravitino-squark/gluino mass plane, implying that gravitinos with masses below 2x10{sup -5} to 1x10{sup -5} eV are excluded for squark/gluino masses below 200 and 500 GeV, respectively. These limits are complementary to the one obtained by the CDF Collaboration, 1.1x10{sup -5} eV, under the assumption of infinitely heavy squarks and gluinos. For the LHC, we conclude that supersymmetric scenarios with light gravitinos will lead to a striking monojet signal very quickly after its startup.},
doi = {10.1103/PHYSREVD.75.115003},
journal = {Physical Review. D, Particles Fields},
number = 11,
volume = 75,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 2007},
month = {Fri Jun 01 00:00:00 EDT 2007}
}
  • We study the discovery potential of the CERN LHC, Fermilab Tevatron and CERN LEP colliders in the search for the neutral CP-even Higgs boson of the MSSM which couples to the weak gauge bosons with a strength close to the standard model one and, hence, plays a relevant role in the mechanism of electroweak symmetry breaking. We place special emphasis on the radiative effects which influence the discovery reach of these colliders. We concentrate on the Vbb(bar sign) channel, with V=Z or W, and on the channels with diphoton final states, which are the dominant ones for the search formore » a light standard model Higgs boson at LEP or Tevatron and LHC, respectively. By analyzing the parameters of the MSSM for which the searches become difficult at one or more of these three colliders, we demonstrate their complementarity in the search for a light Higgs boson which plays a relevant role in the mechanism of electroweak symmetry breaking. (c) 2000 The American Physical Society.« less
  • We analyze the prospects for discovering supersymmetry at the Fermilab Tevatron and CERN LEP colliders in the scenario that the lightest supersymmetric particle is a gravitino of mass {approx_lt}1 keV. We consider in particular the case that the lightest neutralino has a nearly 100{percent} branching fraction into gravitino+photon within the detector. This implies that supersymmetric events should contain both missing (transverse) energy and two energetic photons. Therefore, one can search for supersymmetry simply through inclusive production of superpartners. We consider the exclusion and reach capabilities of the Tevatron in exploring the supersymmetric parameter space, and study the efficiencies which canmore » be achieved in this search. We also consider the discovery reach and backgrounds at LEP with {radical}{ital s}=160, 175, and 190 GeV. {copyright} {ital 1996 The American Physical Society.}« less
  • New heavy quarks with {ital m}{sub {ital Q}}{lt}{ital M}{sub {ital Z}}, if they exist, are produced rather copiously at existing hadronic colliders. If they predominantly decay via unusual modes, thus giving rise to novel signatures, they could have so far evaded detection. The fourth-generation {ital b}{prime} quark, with its diverse decay modes, is studied as an illustration. We focus on the signatures {ital ee}+2{ital j}, {ital p}{sub {ital T}}+2{ital j}, and {gamma}+3{ital j}, while more intriguing signatures are also discussed. Exotic quarks, such as vectorlike quarks, possess signatures that form a subset of these. However, the possible existence of themore » {gamma}+jets mode is unique to {ital b}{prime}. Such quarks, if they exist in the appropriate mass range, could constitute a source of large background to the signals for supersymmetric particles, the Higgs boson, techniparticles, etc. We find that existing hadronic colliders should be able to discover these new heavy quarks if they fall inside the {ital M}{sub {ital Z}}/2{approx lt}{ital m}{sub {ital Q}}{approx lt}{ital M}{sub {ital Z}} range, and {ital m}{sub {ital Q}}{lt}{ital M}{sub {ital H}}{sup 0}.« less
  • We calculate the production cross sections for the vector and pseudoscalar bound states of two gluinos. It is shown that existing and future colliders imply a realistic chance of observing gluinonium as a narrow peak in the two-jet invariant mass spectrum. With an integrated luminosity of 0.2 fb{sup {minus}1} at the Fermilab Tevatron, and the high efficiency for tagging heavy quark jets at CDF, one should be able to detect vector gluinonium for gluino masses up to about 170 GeV, or up to about 260 GeV for an upgraded Tevatron with a center of mass energy of 2 TeV andmore » an integrated luminosity of 1 fb{sup {minus}1}. The significantly higher energy and luminosity of the CERN LHC should allow pseudoscalar gluinonium to be detected for gluino masses up to about 1500 GeV for an assumed luminosity of 200 fb{sup {minus}1}. These results are insensitive to the details of supersymmetry models, provided that {ital R} parity is conserved and the gluinos are lighter than the squarks. In addition, gluinonium detection implies a relatively accurate measure of the gluino mass, which is difficult to determine by other means. {copyright} {ital 1996 The American Physical Society.}« less
  • Recent measurements of the single inclusive jet cross section at the Fermilab Tevatron by the CDF Collaboration may suggest a modified picture of QCD in the large {ital E}{sub {ital T}} range. One possible explanation of the measured jet excess is the introduction of a neutral heavy vector boson {ital Z}{sup {prime}}. A parameter fit of this new model to the CDF data, in leading order perturbation theory, is performed, and the question of how the corresponding single inclusive jet cross sections and the dijet angular distributions at the CERN LHC are affected by this additional {ital Z}{sup {prime}} ismore » discussed. We conclude that the {ital Z}{sup {prime}} will play a pivotal role for typical LHC center-of-mass energies, thus providing a direct test of this theory. {copyright} {ital 1996 The American Physical Society.}« less