cms status report
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CMS Status ReportCMS Status Report
Darin AcostaUniversity of Florida
Welcome to the inverse femtobarn era!
21 September 2011 LHCC CMS Status Report -- D. Acosta 2
Recorded 3.1fb-1 of 3.4 fb-1
delivered Data-taking efficiency is
about 90%
Certification for physics analyses (up to August Stop) 84% for all systems perfect 91% for muon analyses
(without calorimeters)
Used in 2011 physics analyses reported here: 0.23 – 1.7 fb-1
most at 1.1 fb-1
Luminosity uncertainty is 4.5%
Pile-Up
The number of reconstructed vertices after the August Technical Stop increased by factor 1.5 (β*=1.5m 1m ) Fills start with ~15 pile-up
interactions Vertex reconstruction still quite
linear with luminosity
Total inelastic cross section also has been measured from pile-up
σinel(pp)= 68.0 ± 2.0 (Syst) ± 2.4 (Lum) ± 4 (Extrap.) mb.
21 September 2011 LHCC CMS Status Report -- D. Acosta 3
Pile Up
20 vertices
Averaged over fills.
Nrec~ 0.7 x Npu
(PAS FWD-11-001)
before after
Operational Status
Live detector channels Very stable over 2010-11 Forward pixels recovered some channels
Preshower has slight drop due to leakage current in one sensor type
Computing Data rates and storage have been as expected
(LHC live time and trigger rate)21 September 2011 LHCC CMS Status Report -- D. Acosta 4
95%
2010 2011
CMS High Level Trigger Performance
The CMS HLT is performing well in the high luminosity environment
Trigger algorithms and menus have increased in complexity Over 200 multi-object triggers
including tau and b-jet triggers, in addition to single object triggers for electrons, photons, muons, jets, total energy, & missing transverse energy (400 total paths)
Successfully using algorithms such as Particle Flow tau reconstruction
21 September 2011 LHCC CMS Status Report -- D. Acosta 5
Isolated Muon PT > 12 GeV & Hadronic Tau ET > 20 GeV trigger
TAU + MUON
Physics Analyses on 2010 Data
21 September 2011 LHCC CMS Status Report -- D. Acosta 6
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResults Papers, and Physics Analysis Summaries (PAS): http://cdsweb.cern.ch/collection/CMS
69 published, 7 in CWR, 18+ in preparation
Physics Analyses on 2010 Data
21 September 2011 LHCC CMS Status Report -- D. Acosta 7
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResults Papers, and Physics Analysis Summaries (PAS): http://cdsweb.cern.ch/collection/CMS
69 published, 7 in CWR, 18+ in preparation
CMS reached 100 publications on August 3rd 75 from LHC collision data, 24 from the cosmic-ray runs of late 2009 1 is the CMS detector paper.
Physics Analyses on 2011 Data
21 September 2011 LHCC CMS Status Report -- D. Acosta 8
https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResults Papers, and Physics Analysis Summaries (PAS): http://cdsweb.cern.ch/collection/CMS
Summer conference results all new since last LHCC meeting !
Cannot cover it all here
5 submitted, 45 PAS
PAS PHY-11-000
Standard Model
Electroweak: access to proton PDFs
Wμν charge asymmetry vs. ημ W+charm access to strange
21 September 2011 LHCC CMS Status Report -- D. Acosta 10
PAS EWK-11-005, 013
R±c = σ(W+c)/σ(W-c)=0.92 ±0.19(stat.)±0.04(syst.)
Rc = σ(Wc)/σ(W+jets)=0.143 ±0.015(stat.)± 0.024(syst.)NLO predictions:R±
c = 0.91±0.04 Rc =0.13±0.02
Secondary vertex decay length discriminator
Top: tt Cross Section, 1.1 fb-1
21 September 2011 LHCC CMS Status Report -- D. Acosta 11
PAS TOP-11-003, 5, 6, 7
σ(NLO)=158±24 pb
Lepton+jets+b-tag CMS most precise to-date !
Dilepton channel (ee,eμ,μμ) Require at least 1 b-tag
Dilepton channel (μ-τ) Reconstruct hadronic tau decay
All-hadronic channel kinematic fit for mtop
QCD shape from anti-b-tag data
20
11
Top Charge, Mass Asymmetries, 1.1fb-1
Top charge asymmetry Larger than expected
@ Tevatron Lepton+Jets channel Δ(|η|) = |ηt| - |ηtbar|
AC = [N(Δ>0) - N(Δ<0)]/Ntot
= -1.6 ± 3.0(stat) +1.0-1.9(syst) %
AC (theory) = 1.3%
t-tbar mass difference Muon+jets channel Kinematic fit to the mass of the hadronically decaying top Ideogram method
Likelihood calculated for each event to be consistent with mt
Ideogram method applied separately to μ++jets and μ-+jets Δm(t-tbar) = -1.20±1.21(stat)±0.47(syst) GeV
21 September 2011 LHCC CMS Status Report -- D. Acosta 12
PAS TOP-11-014, 019
Exceed’s Tevatron precision
Search for Bs(d) μμ, 1.1 fb-1
Decays are highly suppressed in the SM BR(Bs μμ): (3.2±0.2)x10-9, Bd μμ: (1.0±0.1)x10-10
Indirect sensitivity to new physics MSSM: BR∝(tanβ)6
Blind analysis B+ J/ψ K+ used for normalization B0 J/ψ ϕ used as control regions for efficiencies
Events observed in the unblinded windows are consistent with bkg. plus SM expectations.
CMS BR Limits at 95% CL Bsµ+µ− < 1.9×10−8
Bdµ+µ− < 4.6×10−9
21 September 2011 LHCC CMS Status Report -- D. Acosta 13
arXiv 1107.5834accepted by PRL
CMS + LHCb Combination Bs μμ
CMS BR Limit Bsµ+µ− < 1.9×10−8
LHCb BR limit Bsµ+µ− < 1.5×10−8
Combination of LHCb+CMS: Bsµ+µ− < 1.08×10−8
The value of CLs is in good agreement with background + SM
21 September 2011 LHCC CMS Status Report -- D. Acosta 14
LHCb-CONF-2011-047CMS PAS BPH-11-019
The Higgs
Overview of Searches
Light Higgs Hbb Hττ Hγγ HWW HZZ4l
Medium to Heavy Higgs HWW2l2v (+jets) HZZ (2l2j, 2l2v, 4l, 2l2τ)
21 September 2011 LHCC CMS Status Report -- D. Acosta 16
Hbb, 1.1 fb-1
Search strategy: Associated production with W/Z Boosted W/Z topology, with
H back-to-back with W/Z 2 b-jets (~10% mass resolution) 5 topologies:
WH μvbb, evbb ZH μμbb, eebb ZH vvbb
Two complementary analyses: Cut and count in Mbb
MVA with boosted decision tree
Yields are in good agreementwith data-driven backgroundestimates
21 September 2011 LHCC CMS Status Report -- D. Acosta 17
PAS HIG-11-012
BDT analysis
Hγγ, 1.7 fb-1
21 September 2011 LHCC CMS Status Report -- D. Acosta 18
PAS HIG-11-021
MC for illustration only
Strategy 2 isolated γ’s with PT>40, 30 GeV Data divided into 8 categories
depending on resolution and pT(H) σeff(mass) varies from 1.4 – 7.9 GeV
Background shape fitted by2nd order polynomial in each category
Signal energy resolution extractedfrom Zee data
Hτau τau, SM and MSSM, 1.1-1.6 fb-1
SM categories VBF: 2 jets with Δη>3.5, mjj>350 Non-VBF: <2jets or 2 failing VBF tag
MSSM categories B-tag: ≥1 b jet pT>20 Non-b-tag: <2 jets and no b-tags
Topologies μτh, eτh, eμ (1.6 fb-1), μμ (1.1fb-1) τh ID by “hadron plus strips”,
6% efficiency uncertainty Fit visible mass distribution
21 September 2011 LHCC CMS Status Report -- D. Acosta 19
PAS HIG-11-020
Hτau τau, MSSM Exclusion
21 September 2011 LHCC CMS Status Report -- D. Acosta 20
HWW2l2v, 1.6 fb-1
2 isolated leptons, large MET,no b-tags (to suppress top)
3 categories 0, 1, 2 jets (VBF)
No mass peak Kinematic discrimination by
Mll and Δϕll , exploiting scalar decay
21 September 2011 LHCC CMS Status Report -- D. Acosta 21
Exclude 147–194 GeV @ 95% CL (130-200 expected)
PAS HIG-11-014 EWK-11-010
σ(ppW+W-+X)= 55.3 ± 3.3(stat.)±6.9(syst.)±3.3(lumi) pbσ(NLO)=43±2pb
HZZ 4l (l=e,μ 1.7 fb-1), 2l2τ (1.1 fb-1)
21 September 2011 LHCC CMS Status Report -- D. Acosta 22
PAS HIG-11-015, 013 EWK-11-010
“Golden” decay mode
4l mass resoln. is O(2-3) GeV
σ(ppZZ+X)= 3.8+1.5
-1.2(stat.)±0.2(syst.) ± 0.2(lumi) pb
σ(NLO)=6.4±0.6pb
HZZ 2l2v, 2l2j
21 September 2011 LHCC CMS Status Report -- D. Acosta 23
PAS HIG-11-016, 017
CMS Preliminary
ZZ2l2v Zll Large MET No b-tag jets MT (2l2v) window
ZZ2l2j Likelihood
discriminant based on angular correlations
4 categories based on # b-tags, and a quark/gluon discriminant
Summary of all Searches
Solid lines: observed limits @ 95% CL Dashed lines: expected limits
21 September 2011 LHCC CMS Status Report -- D. Acosta 24
PAS HIG-11-022
Σ (all this work)
SM Higgs Combination
Disfavoured mass region for minimal SM Higgs: Expected: 130 – 440 GeV Observed: 145-216, 226-288, 310-400 GeV
21 September 2011 LHCC CMS Status Report -- D. Acosta 25
PAS HIG-11-022
Higgs with 4 Fermion Generations, 1.1 fb-1
Combination of analyses
Heavy 4th fermion generation coupling to SM Higgs disfavoured over mH=120—600 GeV @ 95% CL
21 September 2011 LHCC CMS Status Report -- D. Acosta 26
PAS HIG-11-011
Overall Search Strategy Inclusive topologies not tied to specific models,
typically but not always with assumption of MET (dark matter)
Generally several approaches within each category, as well as several search regions
Additionally add b-tagging to some categoriesTargeting strongly produced squarks and gluinosEstablish data-driven estimates of backgrounds
21 September 2011 LHCC CMS Status Report -- D. Acosta 28
High yield, high bkgnds. Rare, low bkgnds.(With Z+MET) (And γ+MET)
0 Lepton: new search using MT2, 1.1 fb-1
21 September 2011LHCC CMS Status Report -- D. Acosta29
“Stransverse” mass:
Extension of transverse mass totwo undetected particles (LSPs)
Endpoint corresponds to particle massesUsed here as a discovery discriminant for SUSY: MT2~0 for fake MET, MT2~MET for signalTwo signal regions (high MT2, low MT2 + b-tag)
MT2>400Nj ≥ 3
PAS SUS-11-005
X1
X2
0 Lepton: “αT” Approach, and traditional jets+MET, 1.1fb-1
QCD dijets have edge at 0.5 Processes with real MET have
tail above 0.5 Events with >2 jets are
clustered into 2 pseudo-jets Perform shape analysis of
vs. HT
Traditional jets + MHT
≥3 jets and 3 signal regions in HT (500, 800)and MHT (350, 500)
No excess observed over data-driven bkgds.
21 September 2011 LHCC CMS Status Report -- D. Acosta 30
arXiv:1109.2352
Nj≥2, HT>375
PAS SUS-11-004
MHT (n.b.
)
Single Lepton Search, 1.1 fb-1
Exactly 1 isolated lepton pT>20 (e or μ), ≥3-4 jets, large MET and HT
Two approaches to define signal regionsand to measure backgrounds Use relationship between lepton pT
spectrum and MET (in SM) to predict bkgnd. with HT > 500
Use helicity structure of V-A coupling to W
21 September 2011 LHCC CMS Status Report -- D. Acosta 31
PAS SUS-11-015
Total bkg
Consistent with SM.Similar limits achieved in both approaches
Same Sign Dileptons, 1 fb-1
Clean signature with low SM bkgnds. Consider ee, eμ, μμ, eτh, μτh, τhτh
Complementary baseline selections, used to check bkgnd predictions Inclusive SS dileptons with HT>200 High PT SS dileptons with HT>80 Dileptons with τh and HT>350, MET>80
Define several search regions per selection with tighter cuts on HT and MET:
21 September 2011 LHCC CMS Status Report -- D. Acosta 32
PAS SUS-11-010
Inclusive and τh
High PT
Putting it all Together in CMSSM
21 September 2011 LHCC CMS Status Report -- D. Acosta 33
Summary in Several Simplified Models
21 September 2011 LHCC CMS Status Report -- D. Acosta 34
T1
T2
T5zz
T1lnu
GGM SUSY: Photon(s) + MET, 1.1 fb-1
Diphoton search for general gauge mediated SUSY with the gravitino as the LSP, extended to single photons
Two topologies with large MET 2 or more isolated photons
ET>45, 30 and 1 jet 1 isolated photon ET>75, ≥3 jets
Backgrounds without real MET(QCD with fake γ’s) from data
21 September 2011 LHCC CMS Status Report -- D. Acosta 35
PAS SUS-11-009
Di-γ
Other Exotica
Dilepton Resonance Search,1.1 fb-1
Search for new gauge bosons or new symmetries (EDs) yielding high mass narrow dilepton resonances (ee, μμ)
95% CL mass limits:
21 September 2011 LHCC CMS Status Report -- D. Acosta 37
PAS EXO-11-019
Z’ SSM Z’ Psi RS G* k =0.05 RS G* k =0.1
1.94 TeV 1.62 TeV 1.45 TeV 1.78 TeV
Upper limit on the ratio of Z’ or GKK to SM Z production
W’ Gauge Boson Search, 1.1 fb-1
Isolated single electrons, muons
21 September 2011 LHCC CMS Status Report -- D. Acosta 38
PAS EXO-11-024
W’ with SM couplings excluded @ 95% CL with mass below 2.27 TeV
eμ
combined
e
μ
Dijet Resonance Search, 1.0 fb-1
Search for new narrow resonances in the dijet mass spectrum Templates based on qq, qg, and gg final states
Utilize wide jets to recover radiation (ΔR<1.1)
21 September 2011 LHCC CMS Status Report -- D. Acosta 39
arXiv:1107.4771
String resonance
E6 Diquark q* Axigluon/coloron
W’
4.0 TeV 3.52 TeV 2.49 TeV 2.47 TeV 1.51 TeV
95% CL mass limits:
tt Resonance Search in Boosted Hadronic State, 0.9 fb-1
21 September 2011 LHCC CMS Status Report -- D. Acosta 40
PAS EXO-11-006
Type 1Type 2
Using l+jets sample
Search for heavy resonances (Z’) decaying to top pairs in boosted regime
Classify boost of hadronic decay:1. Merged into single jet2. 2 out of 3 jets merged
Search for types 1+1 and 1+2 2 algorithms to tag merged jets using C-A algo with
R=0.8 using mjet, # subjets, etc. Particle flow inputs
Vector-like Top Quark and 4th Generation
Tt Z Search for FCNC decay of a heavy quark T t Z0
If vector-like, as in Little Higgs theories, could have large BR Full topology: Search for Z(ee or μμ) + additional lepton + at least 2 jets m(T) > 475 GeV @ 95% CL
b’tW Search for trileptons or same-sign leptons, + b-jet m(b’)>495 GeV @ 95% CL
t’bW l+jets: Search for isolated e/μ, large MET, ≥4 jets, b-tag Dileptons: (ee, eμ, μμ), MET, ≥2 jets, 2 b-tags m(t’)>450 GeV (l+jets), 422 GeV (dilep)
21 September 2011 LHCC CMS Status Report -- D. Acosta 41
PAS EXO-11-005
PAS EXO-11-036, 050, 051
Exotica Grand Summary
21 September 2011 LHCC CMS Status Report -- D. Acosta 42
TeV TeV
95% CL exclusion limits
Summary
These are definitely NOT austere times for our science! A very rich physics program has opened up with the first
inverse femtobarn from the LHC ! A broad set of tools and strategies have been developed
SM Reaching precision era, confronting predictions
Higgs No evidence yet, although wide mass regions for minimal SM
Higgs are becoming disfavoured at 95% CL (also heavy 4th generation fermion coupling)
SUSY and Exotica Sensitivity to squark and gluino masses in range 0.5 – 1 TeV Many resonant/non-resonant signals sought
It is a challenge to keep pace with the LHC, but it’s also a very nice situation to be in. Exciting times! Thanks to CERN and the LHC team !
21 September 2011 LHCC CMS Status Report -- D. Acosta 43
Backup
21 September 2011LHCC CMS Status Report -- D. Acosta 44
Electroweak: Dibosons (WW, WZ, ZZ), 1.1fb-1
Measure backgrounds to high mass Higgs search Test for anomalous TGCs
WW (ee,eμ,μμ) Jet and soft b-tag veto Use MET transverse to closest lepton
WZ (eee,eeμ,eμμ,μμμ)
ZZ4l (l=e, μ, or τ)
21 September 2011 LHCC CMS Status Report -- D. Acosta 45
σ(ppW+W-+X)= 55.3 ± 3.3(stat.)±6.9(syst.)±3.3(lumi) pb;
σ(ppWZ+X)= 17.0 ± 2.4(stat.)±1.1(syst.)±1.0(lumi) pb;
σ(ppZZ+X)= 3.8+1.5-1.2(stat.) ± 0.2(syst.) ± 0.2(lumi) pb;
PAS EWK-11-010
WZ
WW
σ(NLO)=43±2pb
σ(NLO)=19.8±0.1pb
σ(NLO)=6.4±0.6pb
Hbb Combined Limits, 1.1fb-1
21 September 2011 LHCC CMS Status Report -- D. Acosta 46
BDT analysis Mbb analysis
PAS HIG-11-012
Local significances and combination
p-value estimates probability of upward background fluctuation as high or higher than the excesses observed in data
Global p-value estimated to be ~0.4
21 September 2011 LHCC CMS Status Report -- D. Acosta 47
CMS PAS 11-022
Dilepton Resonance Search,1.1 fb-1
Search for new gauge bosons or new symmetries (EDs) yielding high mass narrow dilepton resonances
Relatively clean final state
21 September 2011 LHCC CMS Status Report -- D. Acosta 48
PAS EXO-11-019
Combined Dilepton Limits, 1.1 fb-1
Z’ SSM Z’ Psi RS G* k =0.05 RS G* k =0.1
1.94 TeV 1.62 TeV 1.45 TeV 1.78 TeV
21 September 2011 LHCC CMS Status Report -- D. Acosta 49
PAS EXO-11-019
95% CL mass limits:
Upper limit on the ratio of Z’ or GKK to SM Z production
WR and Heavy Neutrino Search, 0.24 fb-1
L-R symmetric extension to SM with parity spontaneously broken Generates WR and Z’ bosons
plus heavy RH neutrinos
Search for resonance structure in ljj and lljj Impose cuts m(ll)>200 and m(lljj)>520 Search in 200 GeV wide bins
21 September 2011 LHCC CMS Status Report -- D. Acosta 50
PAS EXO-11-002
4th Generation Search: b’tW, t’bW
b’ Search for trileptons or same-sign leptons, + b-jet
t’ l+jets: Search for isolated e/μ, large MET, ≥4 jets, b-tag Dileptons: (ee, eμ, μμ), MET, ≥2 jets, 2 b-tags
21 September 2011 LHCC CMS Status Report -- D. Acosta 51
PAS EXO-11-036, 050, 051
m(b’)>495 GeV @ 95% CL
m(t’)>450 GeV (l+jets), 422 (dilep)
tt Resonance Search, 0.9-1.1 fb-1
Boosted top high mass and intermediate mass search:
Semileptonic search in μ+jets: Similar sensitivity
21 September 2011 LHCC CMS Status Report -- D. Acosta 52
PAS EXO-11-006
PAS EXO-11-055
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