Discovering Gluinos at Hadron Colliders SLAC Theory Group Jay Wacker December 5, 2008 In collaboration with: M. Lisanti, J. Alwall, M. Le

Discovering Gluinos at Hadron Colliders High Energy Theory Group 30 Members + 10 Associates from Stanford & UCSC Collider Physics Model BuildingParticle Astrophysics Cosmology String Theory Formal Field Theory

Discovering Gluinos at Hadron Colliders At the Energy Frontier we’re looking for the Nature of Electroweak Symmetry Breaking One big question: Is the Higgs vev radiatively stabilized? Tevatron Final answer requires measuring many couplings, first step is discovery of new particles

Discovering Gluinos at Hadron Colliders Natural Theories of EWSB Technicolour MSSM Low Scale Gravity Warped Dimensions Little Higgs Dimopoulos, Georgi Susskind Arkani-Hamed, Dimopoulos, Dvali Randall, Sundrum Arkani-Hamed, Cohen, Georgi

Discovering Gluinos at Hadron Colliders Supersymmetry Adds 100+ new parameters quarksquark gauge boson gaugino leptonslepton 2 Higgs Higgsinos Lightest susy particle stableDark Matter Susy TeV scale gauge coupling unification Masses and Mixing Angles

Discovering Gluinos at Hadron Colliders Gauge Coupling Unification Susy particles at 100 GeV leads prediction of unification Unification prediction independent of 100+ parameters

Discovering Gluinos at Hadron Colliders Unification restricts Susy parameter space Gaugino masses Independent of other susy parameters Seemed like: Unification

Discovering Gluinos at Hadron Colliders Gauginos Scalar matter Sample Spectra Hadron colliders produce gluinos and squarks Lots of hard jets and missing energy! Leptons aren’t a universal signal

Discovering Gluinos at Hadron Colliders Jets + Missing Energy Searches at D0 1fb -1 analysis (Not exclusive searches)

Discovering Gluinos at Hadron Colliders Results of Searches

Discovering Gluinos at Hadron Colliders Another form of Susy breaking discovered Murayama, Giudice, Rattazzi, Luty, Sundrum, Randall ~ 1999 Anomaly Mediated Susy Breaking Maintained unification had different spectrum for gauginos Should be searching in non-susy theories: Universal Extra Dimensions Choi, Falkowski, Nilles, Olechowski, Pokorski ~ 2004 Later realized that you can mix both types Spectrum of gauginos not predictable from unification Mirage Mediation

Discovering Gluinos at Hadron Colliders What if gluino becomes degenerate with LSP? Missing Energy Cancels! Need to unbalance the momenta:

Discovering Gluinos at Hadron Colliders More Effective Parameter Space Gaugino Unification No obvious mapping between:

Discovering Gluinos at Hadron Colliders Calculating Additional Jets Parton ShoweringMatrix Elements Classical QCD Bremstrahlung Soft/Collinear Approximation Necessary for well-separated jets Includes quantum interference Fixed order calculation Computationally expensive Limited number of partons Resums large logs Computationally Cheap Unlimited number of partons Matching merges best of both worlds Necessary to avoid double counting Need it for the BSM Signal! J. Alwall first to implement in MadGraph

Discovering Gluinos at Hadron Colliders Exclusive Jets + MET Search 4 Separate Searches Leave Free Functions of& Almost identical to existing searches

Discovering Gluinos at Hadron Colliders Proposal for Model Independent Search For each jet multiplicity Set a limit on 4 jets All efficiencies included

Discovering Gluinos at Hadron Colliders No QCD background included 50% background uncertainty Only needs SM Background No missed discoveries Easy to make model dependent exclusions BackgroundsLimits

Discovering Gluinos at Hadron Colliders Tevatron Expected Sensitivity Direct Decay 1 Step Cascade Decay

Discovering Gluinos at Hadron Colliders Being taken forward at Tevatron (4fb -1 ?) Working on the LHC reach 120 GeV Gluino A lot of events, but could look like low p T, QCD, missing energy More generally: Dangers/complications of model dependent searches Need for collaboration between theorists & experimentalists Collaboration between Monte Carlo authors & collider physicists