SUSY08 Seoul 17 June 081 Daniel Teyssier RWTH Aachen University Searches for non-standard SUSY signatures in CMS on behalf of the CMS collaboration

SUSY08 Seoul 17 June 082 Outline : - physics goals - the CMS detector - two photons searches in GMSB - HSCP searches - conclusion

SUSY08 Seoul 17 June 083 Physics goals mGMSB (minimal Gauge Mediated Supersymmetry Breaking) model, with SUSY breaking transmitted via gauge interactions (from hidden sector to visible sector), alternative to mSUGRA 6 parameters to define the model : – Λ (SUSY breaking scale) – M m (messenger mass scale) – N m (number of SU(5) messenger multiplets) – C grav (NLSP lifetime) – tan β – sign(µ) Some sets of parameters give the neutralino as the NLSP and the gravitino as LSP, with BR(χ → γ) > 80% : as sparticles are produced in pairs, final states contain γγ with high p T γγ final states in GMSB G ~ ~

SUSY08 Seoul 17 June 084 Physics goals HSCP (Heavy Stable Charged Particles), τ, g, t Other sets of parameters in mGMSB model predict quasi-stable sleptons (stau) with masses greater than hundred GeV UED (Universal Extra Dimension) model predicts also such quasi-stable sleptons, called KK (Kaluza-Klein) states, with cross-sections of the order of few fb split SUSY (model with high scalar masses) permits the existence of long lived gluino MSSM allows light stop to be the NLSP, with the only possible decay t->cХ and then a long lived stop g and t hadronize to form R-hadrons : R-baryons (gqqq, t 1 qq), R-mesons (gqq, t 1 q) and R-gluonball gg ~ ~ ~ ~ ~~ ~ ~ ~ ~ ~ ~ __

SUSY08 Seoul 17 June 085 CMS detector Tracker : σ pT /p T ≈ 1.5 ∙10 -4 p T (GeV) + 0.5% ECAL : σ E /E ≈ 2.9%/√E(GeV) + 0.5% HCAL : σ E /E ≈ 120%/√E(GeV) + 6.9% Muons : σ pT /p T ≈ 5% for 1 TeV muons Performances of the detector :

SUSY08 Seoul 17 June 086 γγ GMSB Signature : 2 high p T photons, large transverse missing energy (gravitino) and high p T jets Selection based on : – high level trigger used : single γ – photon isolation criteria – p T ( γ) > 80 GeV – p T miss > 160 GeV – p T 4j > 50 GeV gqχ+χ+ qqν l l χ0χ0 γ G ~ ~ ~~ ~ ~

SUSY08 Seoul 17 June 087 γγ GMSB Main background : – QCD multijets and γ+jets : fake MET from mismeasured jets – tt and W+jets : electron could be misidentified as a photon, and possible large MET from neutrinos - - dataset selection non-pointing pointing GMSB Λ=140 TeV Z+jets W+jets QCD TTbar (incl.) Sum background

SUSY08 Seoul 17 June 088 γγ GMSB Significance estimated using likelihood ratio and toy experiments ∫ L dt to get 5 σ for  =140 TeV

SUSY08 Seoul 17 June 089 HSCP : detection techniques Muon-like signature but : - β lower than high relativistic muons (for both lepton-like and R-hadrons) - charge flipping for R-hadrons (trajectory modified and neutral R-hadrons not visible) R-hadrons do not shower in calorimeters : Average R-hadron energy loss per nuclear interaction according to different models hep-ph/

SUSY08 Seoul 17 June 0810 HSCP : β measurement dE/dx using inner tracker : Non Relativistic Particle β -2 ≈ k dE/dX in 0.1< β γ<0.9 region k measured from proton sample Z → µµ sample used as control sample TOF (Time Of Flight) using muon system : Non Relativistic Particle RPC (Resistive Plate Chamber) used to confirm the track, and reject the background, mainly badly measured muons and cosmic muons

SUSY08 Seoul 17 June 0811 HSCP selection SM background t 1 500GeV Samples used : Samples used : Signal : g, t 1, mGMSB τ 1, KK τ 1 (full Geant4 and specific simulation for R-hadrons interactions : R Mackeprang, A Rizzi : Eur.Phys.J.C50: ,2007) SM background : QCD, W/Z+jets, tt Selection criteria : Selection criteria : Muon : p T >30 GeV Tracker : β -1 tk >1.1, N hits >8, χ ² /ndof < 5 Combined: β -1 DT > 1.25, β -1 tk > 1.25 with m avg > 100 GeV Mass measurement : β taken as the average between (β tk,β DT ) and momentum measured in muon system the HSCP mass is calculated ~~ ~~ β -1 tk β -1 DT ~ β -1 tk - CMS AN-2007/049

SUSY08 Seoul 17 June 0812 HSCP results mGMSB τ ~ KK τ 1 t1t1t1t1 SM background and cosmic muons negligible gluino and stop channels to be easily seen after the start-up stau and KK states channels need more integrated luminosity ~ ~ ~ √s=14 TeV ∫ L dt to get 5 σ g Mass spectrum Mass (GeV)

SUSY08 Seoul 17 June 0813 Conclusion γγ GMSB : - discovery possible at startup of the LHC - to cover models up to Λ~200 (300) TeV would need an integrated luminosity of 1 (100) fb -1 HSCP : - high cross-sections and discovery potential from the startup at LHC - mGMSB staus or R-hadrons up to few hundred GeV could be seen in the first 100 pb -1 - KK states more challenging but feasible with more than 1fb -1 - other searches exist on stopped HSCP, that are decaying up to few hours/days after the production

SUSY08 Seoul 17 June 0814 BACKUP

SUSY08 Seoul 17 June 0815 Cross-sections