Interpre'ng a CMS lljjp T Excess With the Golden Cascade of the MSSM

Transcription

1 Interpre'ng a CMS lljjp T Excess With the Golden Cascade of the MSSM Natsumi Nagata October 1st, 214 Journal Club Ben Allanach, Are R. Raklev, and Anders Kvellestad [ ]

2 Mo?va?on CMS (19.4 C - 1, 8 TeV) Opposite- sign same flavor (OSSF) leptons + 2 jets + missing E T events / 5 GeV gnd CMS -1 Preliminary 19.4 fb (8 TeV) Data Background DY (data-driven) Sys. Stat Central Leptons m ll [GeV] CMS- PAS- SUS

3 Mo?va?on CMS (19.4 C - 1, 8 TeV) Opposite- sign same flavor (OSSF) leptons + 2 jets + missing E T events / 5 GeV gnd CMS -1 Preliminary 19.4 fb (8 TeV) Data Background DY (data-driven) Sys. Stat Central Leptons m ll [GeV] 2.6 σ excess!! CMS- PAS- SUS

4 Samples and event selec?on Signal consists of a pair of opposite- sign same- flavor leptons e + e - or μ + μ - p T > 2 GeV and η < 2.4 Exclude 1.4 < η < 1.6 Opposite- sign opposite- flavor leptons (eμ) are used to es?mate the background. Jets (at least two) an?- k T algorithm Jet radius parameter R =.5 p T > 4 GeV and η < 3. Missing energy N jets >= 2 and E T miss > 15 GeV, or N jets >= 3 and E T miss > 1 GeV

5 Background es?mates Flavor- symmetric background - BGs that produce OF pairs as ogen as SF pairs - dominated by h- bar processes - BGs in the signal regions es?mated from events with OF pairs Drell- Yan events - Drell- Yan produc?on of Z / γ * boson (with jets) - yield same- flavor events - es?mated by a control region in the event kinema?cs which does not overlap with the signal region

6 Fit results Events / 5 GeV CMS Preliminary 19.4 fb (8 TeV) Data Fit FS DY Signal m ll [GeV] SF Central Leptons Right triangular shaped kinema?c m ll = 78.7 ± 1.4 GeV Pull m ll [GeV] CMS- PAS- SUS

7 CMS benchmark model Events / 5 GeV CMSPreliminary Data + - DY+jets (e e,µ + µ DY+jets (ττ) WW,WZ,ZZ Madgraph tt single-top - ) Other SM Scaling Uncert. JEC & Pileup Uncert. m~ = 225 GeV m = 15 GeV χ b m~ b m~ b fb = 35 GeV m = 275 GeV 2 χ = 4 GeV m = 15 GeV χ Central Signal Region ee+µµ 2 2 (8 TeV) m ll [GeV] Data / Background Only Data / Background + Signal Data / Background + Signal Roughly Data / Background + Signal in agreement with data CMS- PAS- SUS

8 Today s topic Ben Allanach, Are R. Raklev, and Anders Kvellestad [ ] Interpreta?on in terms of the first two genera?on squark decay In this case, there exists an edge in m ll m max ll = (m2 e 2 m 2 e l )(m 2 e l m 2 e 1) m 2 e l - due to kinema?cs - gives a constraint on parameter space with m ll max = 78.7 GeV

9 Constraint on SUSY par?cle masses m ll max = 78.7 GeV

10 Goal Look for parameter space which accounts for the excess

11 Strategy Free parameters M 2 Right- handed sog mass m elr (Common to first and second genera?on) M 1 is determined by the condi?on for m ll max = 78.7 GeV Squark mass is taken such that the signal rate for the excess is realized Other assump?ons m ell =2m elr All other sog masses decoupled tanβ = 1 (changing it has a negligible effect)

12 Constraints Jets + missing E T, simplified model (gluino decoupled) m χ1 /TeV ATLAS, CMS, ATLAS jets ptmiss CMS jets ptmiss m sq /TeV m χ1 /TeV ATLAS slepton search slepton.1.2 m l /TeV ATLAS,

13 Results 1 8 Allanach, Kvellestad, Raklev, 214 Fails ATLAS jets ptmiss Fails ATLAS slepton m sq /GeV Allanach, Kvellestad, Raklev, 214 Fails ATLAS jets ptmiss Fails ATLAS slepton m sq /GeV m lr /GeV m lr /GeV m χ2 /GeV m χ1 /GeV 6 Some parameter region can explain the excess.

14 Example (fit) 2 15 Allanach, Kvellestad, Raklev, 214 example signal background observed Events/5 GeV m ll /GeV M 2 = 3 GeV, m elr = 2 GeV, m eq = 15 GeV

15 Example (mass spectrum) Mass / GeV 12 1 q L q R l L ν L 2 l R χ 2 χ ± 1 χ 1 h M 2 = 3 GeV, m elr = 2 GeV, m eq = 15 GeV

16 g Allanach, Kvellestad, Raklev, 214 1/2 (g-2) µ /1-1 Fails ATLAS jets ptmiss Fails ATLAS slepton 5 4 m lr /GeV m χ2 /GeV (g 2) µ /2 = (29.4 ± 8.8) 1 1

17 DM relic abundance 1 8 Allanach, Kvellestad, Raklev, 214 Ωh 2 Fails ATLAS jets ptmiss Fails ATLAS slepton.3.25 m lr /GeV Wino dominate m χ2 /GeV h 2 =.1198 ±.26 Coannihila?on with sleptons

18 Prospects m lr /GeV Allanach, Kvellestad, Raklev, 214 Fails ATLAS jets ptmiss Fails ATLAS slepton log 1 (σ qq (LHC-13)/fb) m χ2 /GeV More than 1 C - 1 is required to observe squarks

19 Note ATLAS has not provided a similar analysis of 8 TeV LHC data

20 Some ideas for future work Focusing on DM phenomenology (laher scenario) We have the neutralino DM. Coannihila?on with sleptons play important role Indirect detec?on, direct detec?on, Lithium problem Higgsino in less relevant to the excess g- 2 is also interes?ng

21 Some ideas for future work Focusing on DM phenomenology (CMS interpreta?on) We have the neutralino DM, as well as light sbohom Direct detec?on may be promising χ χ χ χ b b b b g b g Twist- 2 interac?ons Scalar gluon interac?ons

22 Some ideas for future work SUSY breaking models?? Light electroweak gauginos Light sleptons Heavy gluino It may be impossible in CMSSM 1 TeV squarks Heavy or extreemely degenerate staus Heavy or extreemely degenerate 3 rd genera?on squarks

23 Backup

24 OPOF Events / 5 GeV CMSPreliminary fb Data DY+jets (e e,µ + µ ) DY+jets (ττ) WW,WZ,ZZ Madgraph tt single-top Other SM Scaling Uncert. JEC & Pileup Uncert. m~ = 225 GeV m = 15 GeV χ b m~ b m~ b = 35 GeV m = 275 GeV 2 χ = 4 GeV m = 15 GeV χ Central Signal Region eµ 2 2 (8 TeV) m ll [GeV] Data / Background Only Data / Background + Signal Data / Background + Signal Data / Background + Signal