SUSY searches at CMS. Claudio Campagnari UC Santa Barbara

Transcription

1 SUSY searches at CMS Claudio Campagnari UC Santa Barbara 1

2 Outline Brief re- cap of results (7 TeV) Next fronfer (1): Natural SUSY Next fronfer (2): EWK- ino Next fronfer (3): compressed spectra A few words about RPV SUSY (also Stealth SUSY) 8 TeV data, first look CommunicaFon of results Conclusions 2

3 SUSY searches at 7 TeV The inifal SUSY program at CMS was designed to be 1. Generic Signature based searches not tuned to a parfcular SUSY model 2. Broad Cover many possible signatures. Use different methods eg: 4 methods/variables for the all hadronic channel (α T, MHT, MT2, razor) CounFng as well as shapes 3. Robust As data driven and MC- less as possible eg: standard method of normalizing MC to control region and extrapolate to signal region is used as li_le as possible 3

4 Example: E T miss spectrum in single leptons ContribuFon from SM dileptons esfmated from data dilepton sample BG from dileptons + SM single lepton, esfmated from data lepton P T spectrum 4

5 Final states we looked at (all with E T miss ) Fully hadronic 1 lepton 2 leptons Same- sign Opposite sign, but not Z Z MulFleptons 1 photon 2 photons In almost all cases lepton also means τ Most of these searches have a version with b- tags 5

6 We find no excess of events over the SM 6

7 CMSSM interpretafon 7

8 SMS interpretafon 8

9 The next fronfer (1): Natural SUSY CMS & ATLAS searches have excluded light squarks and gluinos up to ~ 1 TeV But are generally not as sensifve to 3 rd generafon squarks RelaFvely light stops are needed for naturalness Gluino cannot be too heavy either Stop is the flavour du jour at the CERN cafeteria 9

10 Looking for natural SUSY Search for stops and sbo_oms in gluino decays Because in natural SUSY the gluino cannot be too heavy Because if the other squarks are very heavy, then the gluino will decay into sbo_oms and stops with high BR Search for stop and sbo_om pair producfon To close the loophole that the gluino is too heavy ExisFng generic searches can be re- interpreted in this context There is sensifvity! New targeted searches are being developed for pair producfon A change of modus operandi at CMS.no real results yet 10

11 Stop from gluino decays Simplified 11

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13 Same as previous page, but for sbo3oms 13

14 Sbo_oms from gluinos again, but different sbo_om decay mode Early 8 TeV result 14

15 Stop Pair ProducFon More dedicated searches in the works 15

16 Sbo_om pair producfon (1) b P 2 b χ 0 1 P 1 b χ 0 1 b 16

17 Sbo_om pair producfon (2) Early 8 TeV result 17

18 The next fronfer (2): EWK producfon High Luminosity à begin to be sensifve to EWK producfon 10 Prospino2.1 tot!pb": pp SUSY S = 7 TeV o 1+ 2o g t 1t 1* q g q q q q * g g 10-3 e e* 2o q LO average SUSY particle mass [GeV]" 18

19 Models with decays into sleptons Models with decays into W and Z P 2 χ 0 2 l l l χ 0 1 P 2 χ 0 2 Z χ 0 1 P 1 χ ± 1 l ν l χ 0 1 P 1 χ ± 1 W χ 0 1 l Z P 2 χ 0 2 l l χ 0 1 P 2 χ 0 3 χ 0 1 P 1 χ ± 1 Trilepton + MET final states Same- sign dileptons to increase eff. ν l ν χ 0 1 P 1 Zà ll + l + MET Zà ll + W/Zà jet- jet + MET Four leptons χ 0 2 Z χ

20 χ+χ 0 Limits Limits in GMSB model with high rate of ZZ+MET [GeV] 0 1 χ m CMS Preliminary LEP2 slepton limit -1 s = 7 TeV, L = 4.98 fb int LEP2 chargino limit miss ~ 3l+E T ( l, BF(3l)=0.5) L miss ~ + - 3l+E T ( l, BF(l l τ)=1) R ~ 3l+M ll +M T & 2l(SS) ( l, BF(3l)=0.5) L ~ + - 3l+M ll +M T & 2l(SS) ( l, BF(l l τ)=1) R ~ 2l2j & 3l+M ll +M T (no l, BF(WZ)=1) σ [fb] 3 10 CMS Preliminary -1 s = 7 TeV, L = 4.98 fb int combined observed UL combined median expected UL (±1σ) 2l2j observed UL 4l observed UL σ NLO theory (±1σ) miss GMSB ZZ + E T m χ ± 1 = m χ 0 χ > m m~ l = m 0 = m ± [GeV] 0.5m ± + 0.5m 0 χ χ χ 1 New 7 TeV result χ [GeV] [1] K. Matchev and S. Thomas, " [2] P. Meade, M. Reece, and D. Shih " [3] J. Ruderman and D. Shih 20 µ

21 Next FronFer (3) : compressed spectra This area is (conservafvely?) not probed unfl the producfon details are be_er understood SensiFvity turns over as spectrum becomes compressed 21

22 Compressed spectra what s coming New analysis techniques under development Parked triggers Lower thresholds on MET and jets To be processed at the end of

23 What about RPV SUSY? Not studied in a great deal of detail Lots of possibilifes However: many of the exofca searches are de- facto sensifve to RPV signatures Because they tend to look at high mass scales Example: 3 rd generafon leptoquark search interpreted as stop search in RPV SUSY (EXO ) Same- sign SUSY dilepton searches are also sensifve Because the E T miss requirements are quite loose A systemafc characterizafon is missing Is it even possible? 23

24 An RPV example: gluinoà 3 quarks Exclude gluino masses below 460 GeV (assuming 100% BR into three jets) 24

25 Stealth SUSY Almost degenerate hidden sector parfcles, results in very li_le E T miss Two photons and at least 4 jets First search of this kind Signal is excess of high S T = H T + E t miss + ΣP T (γ) This is a variable that is sensifve to high mass scales 25

26 Exclude squark masses below 1430 GeV 26

27 8 TeV data A few searches updated with ~ 4 t - 8 TeV Hadronic α T Same- sign dileptons with b- tags Photon(s) + MET Unfortunately, no excess to report 27

28 Extend the gluino exclusion in these scenarios which are interesfng because of naturalness by ~ 60 GeV Early 8 TeV results 28

29 Gauge- mediated SUSY breaking scenarios Depending on the nature of χ 0, single or double photon final states can dominate Early 8 TeV results γγ + MET γ + MET 29

30 CommunicaFon of Results (1) Three years ago many were hoping (dreaming?) that at SUSY12 we would be basking in the glory of the discovery of SUSY And we would be having spirited discussions on how to disentangle the SUSY spectrum LHC Inverse Problem anyone? Alas, it s limits- all- the- 9me 30

31 CommunicaFons of Results (2) We make many pre_y colorful plots. There have been many discussions on how to make our results as useful as possible for the community Some quite ambifous At CMS we pursue two complementary relafvely simple avenues 31

32 Avenue 1: SMS efficiency maps Can be used by a phenomenologist to calibrate a simple MC Example efficiency map for α T search for well defined Simplified Model q P 2 g q χ 0 1 χ 0 1 P 1 g q q 32

33 Avenue 2: Provide efficiency and turn on curves To be used by phenomenologist to build a simple MC Example from SameSign dilepton analysis: lepton efficiencies and H T turn- on curves Feedback by users of these informafon appreciated 33

34 Conclusions Probed a wide variety of SUSY- mofvated final states Nothing found so far, but developed detailed understanding of BG à prerequisite for discovery TransiFoning to targeted searches opfmized for specific, well- mofvated models (eg. ewk SUSY, natural SUSY) Analyses of 8 TeV data are in progress. Expect ~ 20 t - 1 by the end of the year Stay tuned 34

35 Much more on CMS SUSY results in B. Casal Larana Searches for SUSY in hadronic final states at CMS I. Melzer- Pellmann Searches for SUSY in final states with single leptons at CMS D. Sprenger Searches for SUSY in events with di- leptons at CMS K. Theofilatos Searches for SUSY in final states with photons at CMS C. Sanders Searches for SUSY in events with taus at CMS parallel sessions W. Waltenberger InterpretaFons of CMS SUSY analyses in the simplified model space (SMS) M. D'Alfonso Searches for top and bo_om squarks at CMS D. Dobur Search for chargino or neutralino producfon at CMS Y. Chen New results using the razor at the LHC A. Bhay Search for Dark Ma_er at CMS h_ps://twiki.cern.ch/twiki/bin/view/cmspublic/physicsresultssus 35

36 The End 36

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