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Explore how data from the ILC can enhance LHC triggers, optimizing new physics discovery. Propose scenarios for success with a small expert team to identify key physics signals.
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Discussion: How could ILC influence LHC triggers? • Our first report gave many examples of • how LHC+ILC data interpreted together could give new insights • how ILC data could be fed back into the LHC data analyses • All of this could in principle be done even after the completion of LHC • data taking (although it will certainly work better if both machines are • alive simultaneously). • Already in the very first discussion about LHC/ILC studies, it was realized • that an even clearer argument for concurrent running could be made if • a scenario should arise where information from ILC can be used to • modify/upgrade LHC triggers and therefore optimize the acceptance for • certain new physics signals.
In those first discussions some people felt that constructing such a scenario • might be too artificial. • Nevertheless, this question came back to us by people who read our first • report. • Should we make another attempt to work into this direction? • In order to make it a success (given limited human resources) • we should identify one promising scenario to work with • We should find a small team consisiting at least of • a theory expert for the chosen scenario • an LHC trigger (simulation) expert • an ILC contact person • It is clear that in particular without person #2 the project will fail.
Identifying a scenario 2 suggestions from J. Ellis: „Suppose that the LC discovers a (meta)stable massive charged particle, such as a stau in a model with a gravitino LSP. It might be that the LHC experiments would/could modify their trigger and/or even their TOF systems so as to collect these more efficiently.“ „Alternatively, suppose that the LC discovers a massive charged particle that decays rapidly into a lighter neutral particle with a very small mass difference, as occurs in models with a neutralino LSP in the coannihilation region. Perhaps the LHC experiments would/could modify their lepton p_T triggers (replacing them by some other event characteristic? at the expense of some other triggers?) so as to collect these more efficiently.“
H1H2bbbb H1H2bbττ,Yukawa production H2ZbbZ H2ZH1H1ZbbbbZ H1ZbbZ Identifying a scenario Another idea: MSSM Higgs sector with CP-violation LEP cannot exclude a very light (mainly CP-odd) Higgs Detection of H2 seems guaranteed at LHC and ILC but H1 may be more difficult. Question: could LHC see a low-mass (20-50) GeV bbbar resonance if ILC tells its mass? mH1(GeV)
Other ideas from previous CERN meeting: • heavy stable charged particles ( R- hadrons) • ILC input: charginos/neutralinos (not too light but not too heavy) • - then use GUT relation to predict m(gluino) • heavy charginos with low-pt leptons ? • ILC can predict chi03/chi04/chi+2 from chi01/chi02/chi+1 • if cascades at LHC are complicated mass/coupling predictions may help • going down in energy ? • (move from g-dominated to q-dominated pdf’s to reduce bkgd if • low-mass hadronic resonance exisits) • very light rare di-lepton resonance (e.g. gg->“A”-> mumu in CPV MSSM) • Z’ with BR(Z’->hadrons) = 1: • open a mass-window in jet-jet trigger