Recent results from proton-proton collisions at CMS

Transcription

1 Recent results from proton-proton collisions at CMS Ernest Aguiló Physik Institut - Universität Zürich LPHE, Lausanne, Oct. 3st 0

2 Outline Introduction to CMS Detector performance Results on Standard Model Physics: QCD Electroweak B-Physics Top Higgs Results on Physics beyond the SM: SUSY Heavy bosons Fourth generation Leptoquarks Extra dimensions Model-independent searches Ernest Aguiló (UniZh) LPHE, Oct. 3st 0

3 Introduction to CMS Ernest Aguiló (UniZh) 3 LPHE, Oct. 3st 0

4 Detector Performance Tracker: Pixels (440 sensors, 66M pixels) 3 barrel layers, discs / end cap Size: 0 x 50 µm Strips (548 sensors) barrel layers, discs / end cap Width: µm Ernest Aguiló (UniZh) 4 LPHE, Oct. 3st 0

5 Detector Performance Calorimeters: ECAL: PbWO4 crystals HCAL: Cu + scintillator Muon chambers: Drift Tubes Cathode Strip Chambers Resistive Plate Chambers Ernest Aguiló (UniZh) 5 LPHE, Oct. 3st 0

6 Detector Performance Trigger & DAQ: L Trigger: 0kHz maximum rate. Uses multi-object algorithms. HLT: 300Hz maximum rate. Single object + >00 multi-object triggers. Mitigates pile-up. Operational channels RPC 98.5% DT 99.4% CSC 98.3% HB 99.9% HE 0.0% HF 99.9% ES 95.9% EE 98.6% EB 99.% STRIP 97.8% PIXEL 96.9% Ernest Aguiló (UniZh) 6 LPHE, Oct. 3st 0

7 Detector Performance Particle Flow: Use information from all the sub-detectors to build 5 kinds of particles: muons, electrons, photons, charged and neutral hadrons. Use these to build jets, taus and MET. Systematics greatly reduced. B-Tagging: Used to identify b-jets. Uses track IP s, SV s & soft leptons. a.u CMS Preliminary 0, Data Z #!! W+jets tt/ewk QCD s=7 TeV, 36 pb number of events CMS Preliminary 0, s=7 TeV, 36 pb Data * Z/# "! + QCD W + jets * Z/# " µ + tt + jets -! - µ number of events CMS Preliminary 0, s=7 TeV, 36 pb Data * Z/# "! + QCD W + jets * Z/# " µ + tt + jets -! - µ 0 " "" 0 (s) """ reconstructed! decay mode µ! jet visible mass (GeV/c Ernest Aguiló (UniZh) 7 LPHE, Oct. 3st 0 ) µ! jet visible mass (GeV/c )

8 Results on Standard Model Physics

9 QCD Inclusive jet production cross section Inclusive prompt photon production cross section Phys. Rev. Lett. 7 (0) 300 Phys. Rev. D 84 (0) 050 Ernest Aguiló (UniZh) 9 LPHE, Oct. 3st 0

10 Electroweak Ernest Aguiló (UniZh) LPHE, Oct. 3st 0

11 B-Physics Quarkonia: cross-section, B-fraction. Eur.Phys.J. C7 (0) 575 Inclusive cross-sections and angular correlations. Exclusive cross-sections (B +, B 0, Bs). CMS s = 7 TeV, L = 3. pb Phys. Rev.Lett. 6:00(0) Phys. Rev. Lett. 6:500(0) Phys. Rev. D 84:05008 (0) R Ernest Aguiló (UniZh) LPHE, Oct. 3st 0 ratio to PYTHIA B p T PYTHIA MadGraph MC@NLO Cascade > 5 GeV, η B <.0 η Jet < 3.0 Data (p Data (p Data (p Jet T Jet T Jet T > 56 GeV) > 84 GeV) > 0 GeV) Normalisation region JHEP 3 (0) 36

12 Top Re-discovered single top with only 36 pb Phys. Rev. Lett. 7 (0) 0980 Measurement of the pair cross-section at 7 TeV Properties: Mass Mass difference Charge asymmetry TOP-04 Ernest Aguiló (UniZh) LPHE, Oct. 3st 0

13 Higgs H WW: High sensitivity but low resolution (~30 GeV). H gg: Low sensitivity, high resolution (- GeV). Challenging with increasing pile-up. H ZZ: Low sensitivity, high resolution (- GeV) at low masses. Other channels: H tt; associated production (VH Vbb). HIG-0 Ernest Aguiló (UniZh) 3 LPHE, Oct. 3st 0

14 Results on Physics Beyond the SM

15 SUSY Every SM particle has its super-partner with / difference in spin. All hadronic + MET Dominant at the LHC: squark-gluino associated production. Searches: All hadronic + MET Leptons (SS or OS) + jets + MET CMS Preliminary 0 Events / " L dt =. fb, s = 7 TeV Data Standard Model QCD MultiJet tt, W, Z + Jets LM4 LM6 SS leptons ! T Ernest Aguiló (UniZh) 5 LPHE, Oct. 3st 0

16 SUSY ) (GeV/c m / CMS Preliminary & % = LSP 0 Limits q ~ (50)GeV 0 Limits tan# =, A 0 q~ (00)GeV q ~ (750)GeV Lepton = 0, µ > 0 MT SS Dilepton s = 7 TeV, " Ldt =. fb! T CDF D0 LEP LEP Jets+MHT g~, q ~, tan#=5, µ<0 g~, q ~, tan#=3, µ<0 % $ ~ l ± ± g ~ (50)GeV g ~ (00)GeV 300 OS Dilepton g ~ (750)GeV 00 q ~ (500)GeV g ~ (500)GeV m (GeV/c ) 0 ~ Ernest Aguiló (UniZh) 6 LPHE, Oct. 3st 0

17 SUSY MSSM H tt HIG-00 Ernest Aguiló (UniZh) 7 LPHE, Oct. 3st 0

18 Leptoquarks Why leptoquarks? Remarkable symmetry between the 3 generations of quarks and leptons. It s natural to predict (GUT, compositeness, technicolor) particles that carry both baryon and lepton number. Properties: Color-triplet bosons with weak isospin, Can have spin 0 (scalar) or (vector), Fractional electric charge, Couple to a quark and a lepton via Yukawa coupling λ, different for right/left handed, Coupling to one generation only assumed due to absence of FCNC. At the LHC expected to be produced in pairs from gluons (they have color!). Ernest Aguiló (UniZh) 8 LPHE, Oct. 3st 0

19 Leptoquarks β eνjj So far in CMS only 34 pb : st generation LQ search: eejj & enjj channels combined. nd generation LQ serach: only mmjj channel. Physics Letters B 703:3(0) 46 Phys. Rev. Lett.6:080 (0) eejj CMS D exclusion ( fb ) s = 7 TeV eejj 95% CL limit (obs., 33. pb ) eνjj 95% CL limit (obs., 36 pb ) Combined 95% CL limit (obs.) Combined 95% CL limit (exp.) M LQ [GeV] Ernest Aguiló (UniZh) 9 LPHE, Oct. 3st 0

20 Fourth Generation Why 4th generation? mn>45 GeV does not contradict LEP. 4x4 CKM matrix accomodates Belle & D new physics results + matter/anti-matter asymmetry With a 4th generation: successful unification of gauge couplings, hierarchy problem solved. Higgs mass less constrained by electroweak precision measurements. Ernest Aguiló (UniZh) 0 LPHE, Oct. 3st 0

21 Fourth Generation Mt - Mb < MW favored by electroweak measurements then look for t bw. In this analysis both W ln. Select two isolated leptons with pt > 0 GeV, two jets with pt > 30 GeV (not matched to leptons, at least one b-tagged) and MET > 30 GeV. Cut Z mass window. Signal region: both Mlb > 70 GeV. Systematics: b-tagging (%), trigger (%), lepton selection (%), jet & MET energy scale (8%), luminosity (4.5%). ) 500 ) 500 Generated M lb (GeV/c CMS Simulation t't' (M =350 GeV/c ) t' tt (GeV/c Reconstructed M lb Table CMS 3: Simulation Summary of the observed and predicted yields. systematic t't' (M =350 errors, GeV/c apart ) from for di-boson and single top where uncertainties ar tt t' Uncertainties inclu Sample Yield Source t t +.35 ± 0.67 Data Fake leptons Data 0.07 Data DY e + e or µ + µ DY τ + τ 0. ± 0. Simulation Di-boson 0.0 ± 0.0 Simulation Single top 0.07 ± 0.04 Simulation Total prediction Data Generated M lb (GeV/c ) Since no excess beyond the SM background is found, 95% C.L. upper limits Reconstructed section M lb of t t (GeV/c as a function ) of t 36 mass are set, using the CL s method [3, 4]. 37 The limit calculation is based on the information provided by the observed event values and the uncertainties of the luminosity measurement, the background pre 38 Ernest Aguiló (UniZh) LPHE, Oct. 3st 0

22 Fourth Generation No excess beyond SM. Events CMS Preliminary.4 fb at s=7 TeV Events with ee/µµ/eµ Data tt (dileptonic) 95% CL Limits: expected: Mt > 45 GeV EXO-050 Signal Region Other backgrounds t't', M = 350 GeV/c t' observed: Mt > 4 GeV " (pp! t't') pb CMS Preliminary.4 fb s=7 TeV NLO Theory 95% CL s Expected Limits 95% CL s Observed Limits CL s ± " CL s ± " Events (GeV/c ) for M > 70 GeV/c M lb CMS Preliminary.4 fb at s=7 TeV Events with ee/µµ/eµ lb Data tt (dileptonic) Other backgrounds Signal Region t't', M = 350 GeV/c t' M t' (GeV/c ) Ernest Aguiló (UniZh) LPHE, Oct. 3st (GeV/c ) for M > 70 GeV/c M lb lb

23 Other searches: [pb]! 3 CMS preliminary µ Fourth Generation [GeV] M t' EXO-05 "(pp! b'b') [pb] ) (GeV/c = m b' m t' CMS 0 Preliminary Prediction.4 fb observed limit expected limit > 495 GeV/c Limit at 95% CL: M b' CMS Preliminary L =.fb s M b' s = 7 TeV " " [GeV/c = 7TeV expected limit 95% C.L. observed limit 95% C.L. ±! EXO-036 ] EXO-054 arxiv: (hep-ex) > 95% C.L. (Tevatron) V tb Ernest Aguiló (UniZh) 3 LPHE, Oct. 3st 0 A

24 Extra Dimensions Hierarchy Problem: SM interactions can be unified at the energy scale of 6 GeV. GN << a: gravity too weak to be unified at the same scale. Natural energy scale: Planck scale (MP =. 9 GeV). Possible solution: extra dimensions. ADD model (Arkani-Hamed, Dimopoulos and Dvali): n large extra-dimensions of size d >> /MP. At short distances F ~ /r +n. Then MP ~ MD +n d n. For TeV scales d ~ mm if n=. RS-I model (Randall and Sundrum): one wrapped extra-dimension. From both massive Kaluza Klein gravitons appear. Ernest Aguiló (UniZh) 4 LPHE, Oct. 3st 0

25 Extra Dimensions ADD: emission of a KK graviton. Signature: jet + MET Selection: or jets, pt(j)> GeV, h(j) <.4, pt(j)>30 GeV, Df(j,j) < Events / 5 GeV/c 6 CMS Preliminary ADD M D δ L dt =. fb at s=7 TeV Z νν W lν tt QCD + Z l Data - l Events / CMS Preliminary L dt =. fb at s=7 TeV ADD M D δ Z νν W lν tt QCD + Z l Data - l Events / 5 GeV CMS Preliminary L dt =. fb at s=7 TeV EXO-059 ADD M D δ Z νν W lν tt QCD + Z l Data - l! (pb) p CMS Preliminary s=7 TeV, L T int (Jet ) [GeV/c] =. fb ADD, "=! (pb) φ(jet CMS Preliminary s=7 TeV, L =. fb int ADD, "=4, Jet )! (pb) E miss T CMS Preliminary s=7 TeV, L =. fb int ADD, "=6 [GeV] 95% CL Expected limits 95% CL Observed limits Theor. prediction (LO) Theor. prediction (NLO) M D (TeV) 95% CL Expected limits 95% CL Observed limits Theor. prediction (LO) Theor. prediction (NLO) M D Ernest Aguiló (UniZh) 5 LPHE, Oct. 3st 0 (TeV) - 95% CL Expected limits 95% CL Observed limits Theor. prediction (LO) Theor. prediction (NLO) M D (TeV)

26 Extra Dimensions Di-photons: Off-shell ADD KK graviton Entries/0 GeV CMS Preliminary. fb at 7 TeV Observed Diphoton!+jet Dijet Syst. Uncertainty Events/0 GeV CMS Simulation ~ k ~ = 0., M = 750 GeV = 0., M k ~ k = 0., M ~ k = 0., M ~ k = 0., M ~ k = 0., M = 00 GeV = 50 GeV = 500 GeV = 750 GeV = 000 GeV On-shell RS-I KK graviton - - EXO [GeV] M!! M!! [GeV] RS graviton! [pb] median expected 68% expected 95% expected ~ G KK k = % CL limit CMS Preliminary. fb at 7 TeV RS graviton! [pb] median expected 68% expected 95% expected ~ G KK k = % CL limit CMS Preliminary. fb at 7 TeV RS graviton! [pb] median expected 68% expected 95% expected ~ G KK k = 0. 95% CL limit CMS Preliminary. fb at 7 TeV M [GeV] M [GeV] M [GeV] Ernest Aguiló (UniZh) 6 LPHE, Oct. 3st 0

27 Extra Dimensions Photon + MET Cross section (fb) 3 EXO-058 CMS Preliminary s = 7 TeV n=4, Theory NLO n=4, Theory LO n=6, Theory NLO n=6, Theory LO " Ldt =.4 fb 95% CL Obs. Limit 95% CL Exp. Limit ±! Exp. Limit ±! Exp. Limit Di-muon M D (TeV) EXO-039 Ernest Aguiló (UniZh) 7 LPHE, Oct. 3st 0

28 Heavy Bosons Many theories predict the existence of heavier gauge bosons W and Z : Sequential Standard Model GUT s Extra Dimensions (KK bosons) Little, Littlest Higgs Model Technicolor Typical decays: Z to quark or lepton pair (even top pair) W to lepton neutrino or quarks (even bt) W to WZ WR nr " BR(Z'! tt) (pb) Upper Limit # Z' CMS top pair search: All-jets decay channel Divide event in hemispheres Type : 3 sub-jets merged in one Type : The W sub-jets merged in one + b-jet EXO-006 CMS Preliminary, 886 pb at Combined type + & tt Observed (95% CL) Expected (95% CL) ± # Expected ± # Expected KK Gluon, Agashe et al s = 7 TeV Topcolor Z', 3.0% width, Harris et al Topcolor Z',.% width, Harris et al Invariant Mass (TeV/c ) Ernest Aguiló (UniZh) 8 LPHE, Oct. 3st 0

29 Heavy Bosons W en / W mn 0.4 < pt(e/m)/met <.5 EXO-04 Df(e/m,MET) >.5 Limits from fits to MT distributions Events / GeV 7 CMS Preliminary Diboson TTJets+SingleTop $ L dt =.03 fb s = 7 TeV W' % e! DY->ll W->"! W->µ! # +Jets QCD W->e! Data W' (m =.5 TeV) W' M T [GeV] overflow bin +!) (pb) BR(W' " e / µ # CMS Preliminary s = 7 TeV 95% Observed Limit Electron.03 fb 95% Observed Limit Muon.3 fb 95% Observed Combined 95% Expected Combined Theoretical Cross Section W' mass (GeV) Ernest Aguiló (UniZh) 9 LPHE, Oct. 3st 0 Events / GeV CMS Preliminary W " µ! 3 - $ L dt =.3 fb s = 7 TeV W' " µ! WW, WZ, ZZ tt + single-top QCD Z " µµ W " #! Z " ## Data W' (m =.5 TeV) W' M T [GeV] overflow bin

30 Heavy Bosons W WZ EXO-04 Z: pt(m,m) < (5,5) GeV; pt(e,e) < (0,) GeV W: pt(m/e) > 0 GeV; MET > 30 GeV Events / GeV CMS Preliminary 0 s = 7 TeV! L dt =.5 fb Data W+Jets VV tt Z+Jets WZ#3l" W' 600 Optimize HT cut for each signal MC mass BR (pb) "! - -3 CMS Preliminary 0 s = 7 TeV Obs. Limit Exp. Limit ± " ± " " W' # L dt =.5 fb M WZ W' Limit = 784 GeV (GeV) Events / GeV CMS Preliminary 0 s = 7 TeV M WZ Lepton Pt Sum: H T (GeV) ! L dt =.5 fb Data W+Jets VV tt Z+Jets WZ#3l" W' 600 (GeV) Ernest Aguiló (UniZh) 30 LPHE, Oct. 3st 0

31 Model-independent Searches EXO-09 Resonance decaying to dileptons: pt > 35 GeV (40 GeV for ee in EC) Vertex with 4 tracks + cosmic protection Main bakground: Drell-Yan (MC) -4 R σ CMS preliminary, Ldt =.fb - ee+µ + µ median expected 68% expected 95% expected Z' SSM Z' Ψ G KK k/m Pl =0. G KK k/m Pl = % C.L. limit ttbar & QCD estimated from data M [GeV] Events / 5 GeV CMS preliminary s = 7 TeV DATA + - Z/"*!e e tt + other prompt leptons jets (data) # L dt =. fb Events / 5 GeV CMS preliminary s = 7 TeV DATA + - Z/"*!µ µ tt + other prompt leptons jets # L dt =. fb Events / 0 GeV DATA CMS preliminary s = 7 TeV tt + other prompt leptons jets! L dt =. fb m(ee) [GeV] m(µ + µ ) [GeV] Ernest Aguiló (UniZh) 3 LPHE, Oct. 3st m(µ + e /e + µ ) [GeV] -

32 Heavy Stable Charged Particles: Model-independent Searches Using detector information: EXO-0 Tracker: de/dx and p compatible with slow. Muons: time of flight. Stopped HSCP: EXO-00 Created at collision, decays later. Dedicated trigger to select bunch crossings with no collisions. jet pt > 70 GeV. Ernest Aguiló (UniZh) 3 LPHE, Oct. 3st 0

33 Model-independent Searches Other searches: Long lived resonances decaying to leptons: H XX 4 displaced leptons. Bs(d) mm (rare b-decay): BR <.9 8 (4.6 9 ).(0.3) s away from BG only hypothesis. Combination with LHCb: BR>. 8 ~ 3 SM BPH--09 EXO-004 Ernest Aguiló (UniZh) 33 LPHE, Oct. 3st 0

34 Conclusions CMS has shown an excellent performance since start-up in 009. SM physics results in agreement with expectation. Wide range of beyond the SM searches. None found... yet. Tevatron sensitivity surpassed. I had to leave out many results: Ernest Aguiló (UniZh) 34 LPHE, Oct. 3st 0