Flavour changing neutral currents and Higgs interactions in top - - PowerPoint PPT Presentation
Flavour changing neutral currents and Higgs interactions in top quark production and decay Gr egory Hammad on behalf of the ATLAS and CMS collaborations Mons University, Belgium ghammad@cern.ch (Umons) Search for FCNC/H in the top sector
Gr´ egory Hammad
Mons University, Belgium
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 1 / 24
tqX interactions with q = u, c and X = γ, Z, g, H, ?
Standard Model
No FCN interaction at tree level Higher order processes suppressed by the GIM mechanism Ex: B(t → qZ) = O(10−14)
Beyond the Standard Model
Various models (SUSY, ED, etc...) predict higher branching ratios Up to O(10−4) Signs of FCN interactions at a measurable rate at the LHC
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 2 / 24
Theoretical (Optimistic) upper limits on branching ratios
Process SM 2HDM MSSM / R SUSY RS t → cγ 4.6 × 10−14 ∼ 10−6 2 × 10−6 1 × 10−6 ∼ 10−9 t → cZ 1.0 × 10−14 ∼ 10−7 2 × 10−6 3 × 10−5 ∼ 10−5 t → cg 4.6 × 10−12 ∼ 10−4 8 × 10−5 2 × 10−4 ∼ 10−9 t → cH 3.0 × 10−15 ∼ 10−3 ∼ 10−5 ∼ 10−6 ∼ 10−9 Similar values for t → uX except for t → uH (lower values). [J. A. Aguilar-Saavedra, Acta Phys. Pol. B 35 (2004)]
Effective field theory approach
describes effects of new physics at a high energy scale Λ allows to parametrize anomalous couplings in a model-independent way
◮ suitable for model-independent searches for new physics! ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 3 / 24
A very successful Physics Run I
Proton run ended on Dec. 2012. Recorded luminosity: > 21 fb−1 (93 %) A major discovery: Brout-Englert-Higgs boson First observations of rare processes: Bs → µµ, tW, t¯ t + V, etc.
1 M a y 1 J u n 1 J u l 1 A u g 1 S e p 1 O c t 1 N
1 D e c
Date (UTC)
5 10 15 20 25
Total Integrated Luminosity (fb¡1 )
Data included from 2012-04-04 22:37 to 2012-12-16 20:49 UTC LHC Delivered: 23.30 fb¡1 CMS Recorded: 21.79 fb¡1 5 10 15 20 25
CMS Integrated Luminosity, pp, 2012,
ps = 8 TeV
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 4 / 24
7 TeV
Exp. U.L. on BR (95 % C.L.) References tqZ 2.1 fb−1 ATLAS 0.73 %
JHEP 09 (2012) 139
5 fb−1 CMS 0.21 %
8 TeV tqZ 19.7 fb−1 CMS 0.07 % CMS-PAS-TOP-12-037 2 tqH 20.3 fb−1 ATLAS 0.79 % ATLAS-CONF-2013-0813 19.5 fb−1 CMS 1.28 % CMS-PAS-SUS-13-0024
7 TeV
Exp. U.L. on BR (95 % C.L.) tqZ, q=u/c 5 fb−1 CMS 0.51/11.4 % { CMS-PAS-TOP-12-021 tqg, q=u/c 5 fb−1 CMS 0.56/7.12 % 5 fb−1 CMS 0.036/0.034 % CMS-TOP-14-007 5 fb−1 ATLAS 0.0057/0.027 %
8 TeV
Exp. U.L. on BR (95 % C.L.) tqg, q=u/c 14.2 fb−1 ATLAS 0.0031/0.016 % ATLAS-CONF-2013-063 tqγ, q=u/c 19.1 fb−1 CMS 0.016/0.182 % CMS-PAS-TOP-14-003
27+8 TeV data combination: ArXiv:1312.4194, accepted by PRL. 3ArXiv:1403.6293, accepted by JHEP 4ArXiv:1404.5801, submitted to PRD
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 5 / 24
JHEP 09 (2012) 139: tqZ coupling, 2.1 fb−1@7TeV
Tri-lepton final state Event selection
3 isolated leptons (3ID) OR 2 isolated leptons + 1 iso. track (2ID+TL) / ET > 20 GeV at least 2 jets pT > 25 GeV/c ≥ 1 b-tagged jet (2ID+TL)
Event reconstruction
lepton and jet combination:
χ2 =
j1l1l2 − mt 2 σ2 t +
j2l3ν − mt 2 σ2 t +
l3ν − mw 2 σ2 w +
l1l2 − mz 2 σ2 z
select event if reco. masses compatible with mtop/mw/mz
[GeV]
llq
m 140 160 180 200 220 Events / 10 GeV 2 4 6 8 10 12
dibosons Z+jets (SM) t t W/Z t t WbZq signal → t t data
ATLAS
L dt = 2.1 fb
∫
3ID [GeV]
llq
m 140 160 180 200 220 Events / 10 GeV 1 2 3 4 5 6 7 8
data WbZq signal → t t fakes W/Z t t dibosons
L dt = 2.1 fb
∫
2ID + TL ATLAS
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 6 / 24
JHEP 09 (2012) 139: tqZ coupling, 2.1 fb−1@7TeV
Background estimation
No fake lepton: VZ backgrounds, estimated using simulations ≥ 1 fake lepton:
◮ 1 fake lepton (3ID): Z+jets background ⋆ extrapolated from a control region with exactly 1 Z-candidate (2 OSSF leptons) ◮ 1 fake lepton (2ID+TL): fake TL background ⋆ jet-faking-TL rate (vs. jet pT , Nvtx) from γ+jets data sample ◮ ≥ 2 fake leptons (3ID): multi-jet and W+jets backgrounds ⋆ extrapolated from number of same-sign events (l+l+l+ or l−l−l−)
95% CL. upper limits on B(t → qZ)
channel
(−1σ) expected (+1σ) 3ID 0.81% 0.63% 0.95% 1.4% 2ID+TL 3.2% 2.15% 3.31% 4.9% Combination 0.73% 0.61% 0.93% 1.4%
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 7 / 24
CMS-PAS-TOP-12-037: tqZ coupling, 19.7 fb−1@8TeV
Tri-lepton final state Event selection
2 isolated leptons, pT > 20 GeV/c |mll − mZ| < 12 GeV/c2 exactly 1 additional isolated lepton / ET > 30 GeV at least 2 jets pT > 30 GeV/c exactly 1 b-tagged jet
Background estimation
Dominant background processes: VZ, t¯ t and t¯ t + V, with V = W, Z Method based on the number of b-tagged jets observed in data:
Ntot N1 b−tagged jet N2 b−tagged jets = 1 1 1 α0 α1 α2 β0 β1 β2 N0 b−jet ∼ NVZ N1 b−jet ∼ Nsignal N2 b−jets ∼ Nt¯
t+X
with αi, βi = f(ǫbtag, ǫmistag)
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 8 / 24
CMS-PAS-TOP-12-037: tqZ coupling, 19.7 fb−1@8TeV
Event reconstruction and limit settings
Top quark candidate reconstruction:
◮ jet combination maximizing ∆φ(Zj, Wb)
Event yields in 50x70 GeV mass windows: NEst.
Dominant systematic uncertainties:
◮ b-tagging efficiency ◮ top quark candidate mass acceptance ◮ jet energy scale and resolution
Exclusion limits at 95% CL.
B(t → qZ) <0.06% (8 TeV data) B(t → qZ) <0.05% (7+8 TeV data)
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 9 / 24
ATLAS-CONF-2013-081: tqH coupling, 5 + 20 fb−1@7+8TeV
Event selection
g g g b γ γ H t ¯ t Hadronic selection: ≥ 4 jets, pT > 25 GeV/c ≥ 1 b-tagged jet Leptonic selection: ≥ 2 jets, pT > 25 GeV/c mW
T > 30 GeV/c2
Event selected if reco. masses compatible with mtop 2 iso. photons ET > 40/30 GeV mγγ ∈ [100, 160] GeV/c2 Further event classification according to W decay: W → jj or W → lν
[GeV]
j γ γm 50 100 150 200 250 300 350 400 450 500 Events / 5 GeV 10 20 30 40 50 60
Data = 10% Br Signal, j Sherpa γ γ
ATLAS Preliminary
s = 8 TeV √ ,
L dt = 20.3 fb
∫
[GeV]
jjjm 50 100 150 200 250 300 350 400 450 500 Events / 10 GeV 2 4 6 8 10 12 14 16 18 20 22
Data = 10% Br Signal, j Sherpa γ γ
ATLAS Preliminary
s = 8 TeV √ ,
L dt = 20.3 fb
∫
[GeV]
j γ γm 50 100 150 200 250 300 350 400 450 500 Events / 10 GeV 5 10 15 20 25
Data = 10% Br Signal, j Sherpa γ γ
ATLAS Preliminary
s = 8 TeV √ ,
L dt = 20.3 fb
∫
[GeV]
j ν lm 50 100 150 200 250 300 350 400 450 500 Events / 10 GeV 2 4 6 8 10
Data = 10% Br Signal, j Sherpa γ γ
ATLAS Preliminary
s = 8 TeV √ ,
L dt = 20.3 fb
∫
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 10 / 24
ATLAS-CONF-2013-081: tqH coupling, 5 + 20 fb−1@7+8TeV
Statistical analysis
Hadronic selection: template fit to mγγ
◮ template from simulation ◮ compared to data in mγγ side-band regions
Leptonic selection: counting experiment
◮ signal region: mγγ ∈ [123, 129] ◮ bckd. estimated from side band regions
Systematic uncertainties
Photon identification Jet energy scale Effect of ISR/FSR modelling on signal acceptance
[GeV]
γ γ
m 100 110 120 130 140 150 160 Events / 1 GeV 1 2 3 4 5 6 7 8 9
Data j Sherpa γ γ
ATLAS Preliminary
s = 8 TeV √ ,
L dt = 20.3 fb
∫
s = 7 TeV √ ,
L dt = 4.7 fb
∫
Hadronic selection [GeV]
γ γ
m 100 110 120 130 140 150 160 Events / 4 GeV 2 4 6 8 10 12 14 ATLAS Preliminary
s = 8 TeV √ ,
L dt = 20.3 fb
∫
s = 7 TeV √ ,
L dt = 4.7 fb
∫
Hadronic selection Data 2011+2012 Sig+SM Higgs (126.8 GeV)+Bkg fit SM Higgs+Bkg
nd
Bkg (2
Exclusion limits (95 % C. L.): B(t → cH) < 0.79 % →
tuH + λ2 tcH < 0.17
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 11 / 24
CMS-PAS-SUS-13-002: tqH coupling, 19.5 fb−1@8TeV
Model independent search for new physics
Search in events multi-lepton events Search regions divided in HT and / ET bins. Results interpreted in the context of a search for tqH interactions Sensitive to t¯ t → bWqH → blνqH with:
◮ H → WW ∗ → lνlν, ◮ H → ττ, ◮ H → ZZ ∗ → ll + X
Background estimation
DY/t¯ t + (jets faking leptons or γ conversions), normalised from data Simulated / ET or HT distributions, corrected to match data (using dilepton samples)
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 12 / 24
CMS-PAS-SUS-13-002: tqH coupling, 19.5 fb−1@8TeV
Most sensitive regions
OSSF pair Nτhad Emiss
T
[GeV] HT [GeV] Nb-jets data background signal below Z 50–100 0–200 ≥ 1 48 48 ± 23 9.5 ± 2.3 n/a 50–100 0–200 ≥ 1 29 26 ± 13 5.9 ± 1.3 below Z 0–50 0–200 ≥ 1 34 42 ± 11 5.9 ± 1.2 n/a 0–50 0–200 ≥ 1 29 23 ± 10 4.3 ± 1.1 below Z 50–100 > 200 ≥ 1 10 9.9 ± 3.7 3.0 ± 1.1 below Z 0–50 > 200 ≥ 1 5 10 ± 2.5 2.8 ± 0.8 below Z 50–100 0–200 142 125 ± 27 9.7 ± 2.1 n/a 1 0–50 0–200 ≥ 1 237 240 ± 113 13.1 ± 2.6 n/a 50–100 0–200 35 38 ± 15 4.3 ± 1.1 above Z 0–50 0–200 ≥ 1 17 18 ± 6.7 2.8 ± 0.8
Signal yields assumes B(t → qH) = 1%
Rosetta stone
OS: opposite-sign SF: same flavour below Z: mll < 75 GeV/c2 above Z: mll > 105 GeV/c2
95 % C.L. limits on B(t → cH)
Higgs boson decay mode Upper limits on B(t ! cH) Obs. Exp. 1σ range B(H ! WW∗) = 23.1% 1.6 % 1.6% (1.0–2.2)% B(H ! ττ) = 6.2% 7.01% 5.0 % (3.5–7.7)% B(H ! ZZ∗) = 2.9% 5.3% 4.11% (2.9–6.5)% Combined 1.3% 1.2% (0.9–1.7)%
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 13 / 24
CMS-PAS-TOP-12-021: tqg&tqZ couplings, 5 fb−1@7TeV
Single top quark production in association with a Z boson
Tri-lepton final state: pp → t + Z → blν + ll, l = e, µ Sensitive to both tqg and tqZ anomalous couplings Complementary search to:
◮ tqZ interactions with t¯
t events
◮ tqg interactions with single top quark events: qg → t ⋆ Smaller cross-section but smaller background contamination... ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 14 / 24
CMS-PAS-TOP-12-021: tqg&tqZ couplings, 5 fb−1@7TeV
Event selection
3 isolated leptons, pT > 20 GeV/c |mll′ − mZ| < 15 GeV/c2 mW
T = mT(l′′, /
ET) > 20 GeV/c2 at most 1 b-tagged jet
Signal extraction
Boosted Decision Trees (BDT): kinematic variables (pZ
T , ηZ, ηlead.jet, ...)
angular variables (∆φ(Z, /
ET), ∆φ(Z, lW))
(b-tagged) jet multiplicity, ... Template fit to the BDT output including syst. uncertainties as nuisance parameters
Events
20 40 60 80 100 120 BDT output for gut
0.2 0.4 0.6 0.8 1
1 2 3 CMS Preliminary = 7 TeV s at
4.9 fb
channels µ , ee µ µ , e µ µ µ eee,
Data VV non-prompt Lept. , single top t t tZq SM tZ 0.1 pb
Events
20 40 60 80 100 BDT output for Zct
0.2 0.4 0.6 0.8 1
1 2 3 CMS Preliminary = 7 TeV s at
4.9 fb
channels µ , ee µ µ , e µ µ µ eee,
Data VV non-prompt Lept. , single top t t tZq SM tZ 0.1 pb
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 15 / 24
CMS-PAS-TOP-12-021: tqg&tqZ couplings, 5 fb−1@7TeV
Background estimation
Template fit to mW
T distribution:
Z+jets: template derived from data:
◮ Control region obtained by inverting the
isolation criterium on the 3rd lepton
WZ+jets: template from simulations
95 % C. L. exclusion limits
couplings Expected Observed B(t ! gq/Zq) κgut/Λ 0.096 0.096 0.56 % κgct/Λ 0.427 0.354 7.12 % κZut/Λ 0.492 0.451 0.51 % κZct/Λ 2.701 2.267 11.40 % and observed exclusion limits at 95% CL, and the corresponding
Competitive results for κZut with that from t¯ t Results statistically limited
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 16 / 24
CMS-PAS-TOP-14-007: tqg couplings, 5 fb−1@7TeV
Single top (t-ch) event selection
Exactly 1 isolated muon, pT > 20 GeV/c Veto on loose leptons 2 or 3 jets, pT > 30 GeV/c ≥ 1 b-tagged jet
Signal extraction
Bayesian Neural Networks (BNN): kinematic variables:
◮ pb
T , ηµ, ηlead.jet, ...
angular variables:
◮ cos(W, µ)|W, ∆R(j1, j2)
Template fit to the BNN output including syst. uncertainties
#Events
500 1000 1500 2000 2500 3000 3500
Data = 0.04 Λ /
tug
κ = 0.06 Λ /
tcg
κ t-chan s-chan tW-chan t t W+light Wc WQQ W(other) Diboson Drell-Yan QCD
= 5.0 fb L = 7 TeV, s CMS preliminary, tug FCNC BNN
0.0 0.2 0.4 0.6 0.8 1.0
MC Data-MC
0.0 0.2 0.4
#Events
500 1000 1500 2000 2500 3000
Data = 0.04 Λ /
tug
κ = 0.06 Λ /
tcg
κ t-chan s-chan tW-chan t t W+light Wc WQQ W(other) Diboson Drell-Yan QCD
= 5.0 fb L = 7 TeV, s CMS preliminary, tcg FCNC BNN
0.0 0.2 0.4 0.6 0.8 1.0
MC Data-MC
0.0 0.2 0.4
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 17 / 24
CMS-PAS-TOP-14-007: tqg couplings, 5 fb−1@7TeV
Multijet background
rejected with a dedicated BNN:
◮ Variables: mW
T , /
ET , pµ
T , ...
◮ +10 % in signal eff. wrt to a cut on mW
T
Statistical analysis
Simultaneous fit for κtug and κtcg Account for correlated uncertainties Marginalisation of nuisance parameters (JES,JER, b/mis-tag eff., ...)
95 % C. L. (1D) exclusion limits
B(t → ug) < 3.55 × 10−2% B(t → cg) < 3.44 × 10−1%
QCD efficiency | QCD BNN cut 0.2 0.4 0.6 0.8 1 Signal efficiency 0.2 0.4 0.6 0.8 1
= 5.0 fb L = 7 TeV, s CMS preliminary,
MtW cuts QCD BNN cuts QCD BNN cut vs sig.eff. QCD BNN = 0.7 points
discriminator for the trained (”train”) and tested
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 18 / 24
ATLAS-CONF-2013-063: tqg couplings, 14.2 fb−1@8TeV
Dedicated search for qg → t → W(→ lν)b (production via FCNC)
Main difference w.r.t to SM single top production (t-ch.): pt
T ∼ 0 (arises only from ISR)
◮ back-to-back decay products (W,b)
Differences w.r.t. to SM W/Z+jets and diboson prod.: W boson with higher momentum decay products (l, ν) with small opening angles u/c g t b W
Event selection
Exactly one isolated lepton (e,µ), pT > 25 GeV/c and |η| < 2.5 Exactly one jet, pT > 30 GeV/c with tight b-tagging requirement. / ET > 30 GeV mW
T > 50 GeV/c2
Background processes
Multi-jet: estimated from data
◮ template fit to /
ET (elec. chan.)
◮ matrix method (mu. chan.)
Other SM processes estimated with simulations:
◮ W+(LF/HF) jets ◮ SM single top and t¯
t prod.
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 19 / 24
ATLAS-CONF-2013-063: tqg couplings, 14.2 fb−1@8TeV
Statistical analysis:
Bayesian analysis using a binned likelihood applied to a Neural Network output Neural Network:
◮ 13 variables: pb
T ,pW T ,∆φ(W, ν)...
◮ modelling checked in control region
(b-tagging requirement inverted)
Dominant syst. uncertainties:
◮ jet energy scale ◮ b/mis-tagging efficiency
(b) [GeV]
Tp 50 100 150 Data/Expected 0.8 1 1.2 Events / 6 GeV 50 100 150 200
310 ×
data single-top t t W+jets W+HF+jets Z+jets multijets MC stat. uncert. multijets norm. + = 8 TeV s ,∫
Preliminary ATLAS
control region (W) [GeV]
Tp 50 100 150 Data/Expected 0.8 1 1.2 Events / 8 GeV 50 100
310 ×
data single-top t t W+jets W+HF+jets Z+jets multijets MC stat. uncert. multijets norm. + = 8 TeV s ,∫
Preliminary ATLAS
control region | [rad]
t-rest) ν (W, φ ∆ | 1 2 3 Data/Expected 0.8 1 1.2 Events / 0.2 rad 20000 40000 60000 80000
data single-top t t W+jets W+HF+jets Z+jets multijets MC stat. uncert. multijets norm. + = 8 TeV s ,∫
Preliminary ATLAS
control region
Events / 0.13 5000 10000 15000 20000 25000
data =20 pb) σ FCNC ( single top t t W+HF+jets W+jets Z+jets, diboson multijets MC stat. uncert. multijets norm. += 8 TeV s
L dt = 14.2 fb
∫
Preliminary ATLAS signal region NN output
0.2 0.4 0.6 0.8 1 Data/Expected 0.8 0.9 1 1.1 1.2
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 20 / 24
CMS-PAS-TOP-14-003: tqγ couplings, 19.1 fb−1@8TeV
Event selection
Exactly 1 iso. photon, pT > 50 GeV/c Exactly 1 iso. muon, pT > 26 GeV/c Loose lepton veto, pT > 10 GeV/c ≥ 2 b-tagged jet event veto / ET > 30 GeV u/c g u/c b ν µ+ W + t γ
Signal extraction
Boosted Decision Tree (BDT): kinematic variables (pγ
T, pb T, pµ T , ...)
angular variables (∆R(γ, µ), ∆R(γ, b)) jet multiplicity, ... Template fit to the BDT output including syst. uncertainties as nuisance parameters
h_copy Entries 46 Meanγ BDT output for tu
0.2 0.4 0.6 0.8 DATA/MC 1 2
h_copy Entries 46 MeanEvents / 0.1
100 200 300 400 500 600 700 800 900 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb
Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst mu_BDT__zjethist Entries 3641 Mean
RMS 0.1104 mu_BDT__zjethist Entries 3641 Mean
RMS 0.1104
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 21 / 24
CMS-PAS-TOP-14-003: tqγ couplings, 19.1 fb−1@8TeV
Background estimation
Template fit to cos(W, γ) distribution: W+jets: template derived from data
◮ Control region: inverted cut on the
EM shower shape σiηiη
Wγ+jets: template from simulations
) γ Cos(W,
0.2 0.4 0.6 0.8 1
Events / 0.07
20 40 60 80 100 120 140 160 180 BDT output
= 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3639 Mean
RMS 0.6225 mu_BDT__zjethist Entries 3639 Mean
RMS 0.6225
95 % C. L. exclusion limits
σtuγ × Br(W ! lνl) 0.0404 pb 0.0234 pb 0.0408 pb 0.0217 pb σtcγ × Br(W ! lνl) 0.0411 pb 0.0281 pb 0.0410 pb 0.0279 pb κtuγ 0.0367 0.0279 0.0315 0.0229 κtcγ 0.113 0.094 0.0790 0.0652 Br(t ! uγ) 0.0279% 0.0161% 0.0205% 0.0108% Br(t ! cγ) 0.261% 0.182% 0.193% 0.132%
First results for κtqγ at the LHC Significant improvement w.r.t. to HERA’s measurement (ZEUS,H1).
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 22 / 24
Growing interest in indirect but model-independent searches for new physics No sign of FCN interactions in the top quark sector so far Limits on B(t → qZ) and B(t → qg):
◮ getting close to theoretical predictions for some BSM models...
First limits on B(t → qH):
◮ already at the % level. Just a beginning...
First limits on B(t → qγ) from the LHC:
◮ significant improvements w.r.t. HERA limits.
) γ q → BR(t
10
10
10
10
10 1
qZ) → BR(t
10
10
10
10
10 1
CDF D0 DELPHI ATLAS CMS (q=u) (q=c) Preliminary CMS ZEUS (q=u) (q=u) H1 EXCLUDED REGION 95% C.L
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 23 / 24
Preliminary projections for the High-Luminosity LHC Run at 13/14 TeV: 3000 fb−1 of integrated luminosity < 140 > pile-up events per bunch-crossing Exclusions limits at 95 % C.L.: B(t → qZ) < 10−4
◮ [ATL-PHYS-PUB-2012-001] ◮ [CMS-FTR-13-016]
B(t → qγ) < 3 × 10−5
◮ [ATL-PHYS-PUB-2012-001]
B(t → qH) < 1.5 × 10−4
◮ [ATL-PHYS-PUB-2013-012] ) γ q → BR(t
10
10
10
10
10 1 qZ) → BR(t
10
10
10
10
10 1
LEP
(q=u only)
ZEUS
(q=u only)
H1 D0 CDF )
ATLAS (2 fb )
CMS (4.6 fb ATLAS preliminary (simulation) extrapolated to 14 TeV:
300 fb (sequential)
3 ab (sequential)
3 ab (discriminant)
95% C.L. EXCLUDED REGIONS
Exciting times ahead in the top quark sector!
Thank you.
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
JHEP 09 (2012) 139: tqZ coupling, 2.1 fb−1@7TeV
3ID 2ID+TL ZZ and WZ 9.5 ± 4.4 1.0 ±
0.5 0.6
t¯ tW and t¯ tZ 0.51 ± 0.14 0.25 ± 0.05 t¯ t, WW 0.07 ± 0.02 7.6 ± 2.2 Z+jets 1.7 ± 0.7 Single top 0.01 ± 0.01 2+3 fake leptons 0.0 ±
0.2 0.0
Expected background 11.8 ± 4.4 8.9 ± 2.3 Data 8 8 Signal efficiency (0.205 ± 0.024)% (0.045 ± 0.007)%
Table 1. Expected number of background events, number of selected data events and signal efficiency (normalized to all decays of the W and Z bosons), after the final event selection. The t¯ t backgrounds correspond to SM decays of the top quarks. The third entry in the 2ID+TL column corresponds to the fake TL background and includes all sources of events in the left-hand column except ZZ, WZ, t¯ tW and t¯ tZ.
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
JHEP 09 (2012) 139: tqZ coupling, 2.1 fb−1@7TeV
3ID 2ID+TL Source Background Signal Background Signal Luminosity 4% 4% <1% 4% Electron trigger 4% 1% <1% <1% Electron reconstruction modelling 10% 3% <1% 2% Muon trigger 3% 1% <1% <1% Muon reconstruction modelling 7% 1% <1% 1% TL reconstruction modelling — — 2% 1% Jet energy scale 11% 1% 1% 1% Jet reconstruction efficiency 5% 2% <1% <1% Jet energy resolution 1% 3% 1% 4% Emiss
T
modelling 4% 1% <1% <1% LAr readout problem 3% 1% <1% 1% Pile-up 4% <1% <1% <1% b-tagging — — 1% 6% Top quark mass <1% 2% — 3% σt¯
t
<1% 8% — 8% ISR/FSR <1% 3% — 6% PDFs — 3% — 3% ZZ and WZ shape 33% — 5% — ZZ and WZ cross section 4% — <1% — ZZ and WZ heavy-flavour content — — <1% — Fake leptons 1% — 17% — Total 38% 12% 18% 15%
Table 2. Relative changes in the expected number of background events and signal yield for differ-
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
JHEP 09 (2012) 139: tqZ coupling, 2.1 fb−1@7TeV
[GeV]
miss T
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L dt = 2.1 fb
3ID [GeV]
miss T
E 40 80 120 160 200 Events / 10 GeV
10 1 10
2
10
3
10
4
10
data fakes W/Z t t dibosons
L dt = 2.1 fb
2ID + TL ATLAS
(a) (b)
Figure 2. Emiss
T
distributions in control regions for the (a) 3ID and (b) 2ID+TL events. The 3ID control region is defined by two same-flavor, opposite-charge leptons with an invariant mass within 15 GeV of MZ = 91.2 GeV. The 2ID+TL control region is defined by two ID leptons, one TL and exactly one jet. In the 2ID+TL case, backgrounds from t¯ t and W and Z plus jets are included in the ‘fakes’ contribution.
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
CMS-PAS-TOP-12-037: tqZ coupling, 19.7 fb−1@8TeV
Table 2: Expected number of signal t → Zq events, background composition, and observed events corresponding to an integrated luminosity of 19.7 fb−1 for all dilepton channels; back- ground estimates included. The uncertainties in the background estimation include the statis- tical and systematic components shown separately, in that order. Process Estimation from data MC prediction t → Zq (B = 0.1%) — 6.4 ± 0.1 ± 1.3 WZ 1.4 ± 0.1 ± 0.3 0.9 ± 0.1 ± 0.3 ZZ < 0.1 Drell–Yan < 0.1 tt 1.7 ± 0.8 ± 0.4 0.7+1.1
−0.4 ± 1.2
ttZ 1.1 ± 0.1 ± 0.8 ttW 0.1 ± 0.1 ± 0.1 tbZ 0.3 ± 0.1 ± 0.2 Total background 3.1 ± 0.8 ± 0.8 3.2 ± 1.2 ± 1.5 Observed events 1 —
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
CMS-PAS-TOP-12-037: tqZ coupling, 19.7 fb−1@8TeV
Table 3: Summary of the systematic uncertainties for the signal selection acceptance. An addi- tional 2.6% uncertainty is due to the luminosity measurement. Source Uncertainty % Renormalization/factorization scales 12 Parton distribution functions 7 tt cross section 7 Parton matching threshold 6 Lepton selection 6 Trigger efficiency 5 b-tagging 5 Top-quark mass 4 Jet energy scale 4 Missing transverse energy resolution 3 Pileup modeling 3 Total 20
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
CMS-PAS-FTR-13-016: tqZ coupling, 300 − 3000 fb−1@14TeV
[GeV]
Zj
m
100 150 200 250 300
Events / 20 [GeV]
200 400 600 800 1000 1200 1400 1600 1800 2000
= 0.1%) B Zq ( → t W/Z + Jets + Jets t t , tqV t Vt WW/WZ/ZZ
CMS Projection = 14 TeV s at
3 ab
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
CMS-FTR-13-016: tqZ coupling, 300 − 3000 fb−1@14TeV
Projections of exclusion limits at 14 TeV
analysis similar to CMS-TOP-12-037 parametrized detector simulation (DELPHES) high pile-up scenario: 140 collisions/event
Exclusion limits at 95% CL. on B(t → qZ)
B(t ! Zq) 19.5 fb−1 @ 8 TeV 300 fb−1 @ 14 TeV 3000 fb−1 @ 14 TeV
3.2 26.8 268 Expected limit < 0.10% < 0.027% < 0.010% 1 σ range 0.06 − 0.13% 0.018 − 0.038% 0.007 − 0.014% 2 σ range 0.05 − 0.20% 0.013 − 0.051% 0.005 − 0.020%
systematic uncertainties decreased by a factor 0.25 19.5 fb−1/La
aexcept on the /
ET resolution
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
CMS-PAS-FTR-13-016: tqZ coupling, 300 − 3000 fb−1@14TeV
Table 2: The expected SM background contributions at 14 TeV with 3000 fb−1 data. The cross sections of each process shown are based on leading order (LO) calculations times the corre- sponding k-factors, which are obtained from the next-to-next-to-leading logarithmic (NNLL) + next-to-next-to-leading order (NNLO) [12] or next-to-leading order (NLO) cross section calcu- lations [13, 14]. The uncertainties shown contain only the statistical uncertainty on simulated samples. Process Cross section (pb) Order Expected @ 3000 fb−1 top FCNC signal 1.91 NNLL 578 ± 13 vector boson + jet 338 × 103 NLO < 55 di-boson + jets 412 NLO 40 ± 31 top pair + jets 954 NNLL 70 ± 57 single top + jets 323 NLO < 8 boson + top + jets 97.3 NLO 15 ± 15 boson + top pair + jets 3.97 NLO 144 ± 14
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CMS-PAS-FTR-13-016: tqZ coupling, 300 − 3000 fb−1@14TeV
Table 4: Summary of the systematic uncertainties for the background estimation in percent. Uncertainty (%) 19.5 fb−1 @ 8 TeV 300 fb−1 @ 14 TeV 3000 fb−1 @ 14 TeV Jet energy scale 13.5 3.5 3.4 ET / resolution 3.2 3.2 3.2 MC Statistics 5.3 1.4 1.3 σ(tqZ)/ σ(Vtt) 3.1 1.0 0.8 b-tagging 17.7 4.5 4.2 Total 23 7 7
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ATLAS-CONF-2013-081: tqH coupling, 5 + 20 fb−1@7+8TeV
Table 2: Number of selected events at different levels of the fully hadronic analysis, at 7 and 8 TeV. The row “Weighted events” includes for each MC event the weight as defined in Sec. 2.5. For each column, “Protos” corresponds to the sum of the hadronic and the leptonic samples weighted by the ratio of the W decays to leptonic and hadronic modes (0.48). Events Protos-8TeV Protos-7TeV Sherpa Data-8 TeV Data-7 TeV Simulated 44379 44379 107
15076 15452 1257544 118893 23683 4-jets (or more) 6596 6709 23101 1357 227 Preselected (mass cuts) 2662 2614 3022 211 36 Selected (1 b-tag or more) 1896 1907 690 43 7 Weighted events 1835 1925 701 43 7
62 55 34
41.3·10−3 43.4·10−3 70·10−6
1.4·10−3 1.2·10−3 3.4·10−6
Search for FCNC/H in the top sector 27/05/2014 24 / 24
ATLAS-CONF-2013-081: tqH coupling, 5 + 20 fb−1@7+8TeV
Table 3: Number of selected events at different levels of the analysis, in the leptonic decay mode, at 8 TeV. The row “Weighted events” includes for each MC event the weight as defined in Sec. 2.5. The column “Protos” corresponds to the sum of the leptonic and of the hadronic samples weighted by the ratio of the W decays to hadronic and leptonic modes (2.09). Events Protos-had Protos-lep Protos Sherpa Data Simulated 30000 30000 92593 107
10054 10478 31454 1257544 118893 1ℓ, 2 j, mT > 30 GeV 3 3450 3456 40 30 + mass cuts 2 1680 1684 6 4 Selected (1 b-tag or more) 2 1171 1175 1 Weighted events 4.0 1190 1198 1 Efficiency 0.1·10−3 39.7·10−3 12.9·10−3
0.1·10−3 1.5·10−3 0.6·10−3
Search for FCNC/H in the top sector 27/05/2014 24 / 24
ATLAS-CONF-2013-081: tqH coupling, 5 + 20 fb−1@7+8TeV cH) → Br(t 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016
S
CL
10
10
10 1 ATLAS Preliminary
s = 8 TeV √ ,
L dt = 20.3 fb
s = 7 TeV √ ,
L dt = 4.7 fb
Observed Expected σ 1 ± σ 2 ±
Figure 7: Evolution of CLs as a function of Br for the observation (full line) and the expectation in the absence of signal (dashed line). The bands at 1 and 2 σ around the expected curve are also shown.
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
CMS-PAS-SUS-13-002: tqH coupling, 19.5 fb−1@8TeV Source of Uncertainty Uncertainty Luminosity 4.4% PDF 14% Renormalization Scale 10% Emiss
T
Resolution/Smearing: 0 − 50 GeV, 50 − 100 GeV, > 100 GeV (-3%, +4%, +4%) Jet Energy Scale W±Z 0.5% (WZ) B-Tag Veto 0.1% (WZ), 6% (t¯ t) Muon ID/Isolation at 10 (100) GeV 11% (0.2%) Electron ID/Isolation at 10 (100) GeV 14% (0.6%) Tau ID/Isolation at 10 (100) GeV 2% (1.1%) t¯ t cross-section/fake rate 50% WZ normalization 6% ZZ normalization 12% Internal conversion fake rate 100% Table 5: The systematic uncertainties associated with this analysis. The Emiss
T
resolution sys- tematic is given for WZ background on Z for different cuts on Emiss
T
and for different cuts on MT given a cut of Emiss
T
> 50 GeV.
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CMS-PAS-TOP-12-021: tqg&tqZ couplings, 5 fb−1@7TeV Cut signal (0.1 pb) t¯ t SingleTop DY lepton selection 98.6 ± 3.6 12.0 ± 0.5 0.9 ± 0.3 233.0 ± 12.8 Z mass cut 89.7 ± 3.5 3.8 ± 0.3 0.4 ± 0.2 187.8 ± 8.2 jet multiplicity 78.6 ± 3.3 3.5 ± 0.3 0.3 ± 0.2 55.6 ± 4.5 b-jet multiplicity 73.8 ± 3.2 3.1 ± 0.3 0.3 ± 0.2 55.6 ± 4.5 mW
T
62.4 ± 2.9 2.8 ± 0.2 0.2 ± 0.2 40.2 ± 3.8 Cut Diboson tZq total Background Data lepton selection 775.9 ± 2.2 5.0 ± 0.2 1026.7 ± 13.0 891.0 ± 29.8 Z mass cut 471.1 ± 2.1 4.4 ± 0.2 667.6 ± 8.4 667.0 ± 25.8 jet multiplicity 197.6 ± 1.4 4.4 ± 0.2 261.4 ± 4.7 245.0 ± 15.7 b-jet multiplicity 179.3 ± 1.3 3.1 ± 0.1 241.5 ± 4.7 231.0 ± 15.2 mW
T
157.1 ± 1.3 2.8 ± 0.1 203.2 ± 4.0 195.0 ± 14.0 Table 1: Event yield after the different steps of the event selection. Uncertainty is statistical
0.1 pb.
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ATLAS-CONF-2013-063: tqg couplings, 14.2 fb−1@8TeV
(b) [GeV]
Tp 50 100 150 Data/Expected 0.8 1 1.2 Events / 6 GeV 50 100 150 200
310 ×
data single-top t t W+jets W+HF+jets Z+jets multijets MC stat. uncert. multijets norm. + = 8 TeV s ,∫
Preliminary ATLAS control region(W) [GeV]
Tp 50 100 150 Data/Expected 0.8 1 1.2 Events / 8 GeV 50 100
310 ×
data single-top t t W+jets W+HF+jets Z+jets multijets MC stat. uncert. multijets norm. + = 8 TeV s ,∫
Preliminary ATLAS control region| [rad]
t-rest) ν (W, φ ∆ | 1 2 3 Data/Expected 0.8 1 1.2 Events / 0.2 rad 20000 40000 60000 80000
data single-top t t W+jets W+HF+jets Z+jets multijets MC stat. uncert. multijets norm. + = 8 TeV s ,∫
Preliminary ATLAS control regiona) b) c)
(b) [GeV]
Tp 50 100 150 Data/Expected 0.8 1 1.2 Events / 6 GeV 10000 20000 30000
data single-top t t W+jets W+HF+jets Z+jets multijets MC stat. uncert. multijets norm. + = 8 TeV s ,∫
Preliminary ATLAS signal region(W) [GeV]
Tp 50 100 150 Data/Expected 0.8 1 1.2 Events / 8 GeV 5000 10000 15000 20000
data single-top t t W+jets W+HF+jets Z+jets multijets MC stat. uncert. multijets norm. + = 8 TeV s ,∫
Preliminary ATLAS signal region| [rad]
t-rest) ν (W, φ ∆ | 1 2 3 Data/Expected 0.8 1 1.2 Events / 0.2 rad 5000 10000 15000
data single-top t t W+jets W+HF+jets Z+jets multijets MC stat. uncert. multijets norm. + = 8 TeV s ,∫
Preliminary ATLAS signal regiond) e) f) Figure 3: Kinematic distributions of the three most significant variables: transverse momentum of the b- jet pT(b) a),d), the transverse momentum of the W boson pT(W) b),e), and the difference of the azimuthal angle between the W boson and the neutrino in the top quark rest frame |∆φ(W, ν)t−rest| c),f) shown in the control region a)-c) and the signal region d)-f). All processes are normalised using the scale factors
T
from the simulated samples size and the uncertainty on the multijet normalisation. ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
ATLAS-CONF-2013-063: tqg couplings, 14.2 fb−1@8TeV
(b) [GeV]
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p 50 100 150 Event fraction / 6 GeV 0.1 0.2 0.3 0.4
FCNC t t W+HF+jets multijets Simulation Preliminary ATLAS
signal region (W) [GeV]
T
p 50 100 150 Event fraction / 8 GeV 0.1 0.2 0.3
FCNC t t W+HF+jets multijets Simulation Preliminary ATLAS
signal region
a) b)
| [rad]
t-rest
) ν (W, φ ∆ | 1 2 3 Event fraction / 0.2 rad 0.1 0.2
FCNC t t W+HF+jets multijets Simulation Preliminary ATLAS
signal region
c) Figure 4: Kinematic distributions of the three most significant variables in the signal region normalised to unit area: transverse momentum of the b-jet pT(b) a), the transverse momentum of the W boson pT(W) b), and the difference of the azimuthal angle between the W boson and the neutrino in the top quark rest frame |∆φ(W, ν)t−rest| c). The last histogram bin includes overflow events.
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ATLAS-CONF-2013-063: tqg couplings, 14.2 fb−1@8TeV
Table 3: Variables used as input to the neural network ordered by their importance, as estimated from the total correlation loss to the target caused by its removal. loss of total loss of total Variable correlation (%) Variable correlation (%) pT(b) 34 ∆φ(`, W) 6 pT(W) 19 ∆φ(b, `νb) 5 ∆φ(W, ν) in the top quark rest frame 13 ∆R(`, `νb) 5 Charge of the lepton q(`) 12 ∆φ(W, `νb) 4 η(`) 11 η(ν) 4 ∆φ(`, b) 9 Emiss
T
4 η(`νb) 9
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ATLAS-CONF-2013-063: tqg couplings, 14.2 fb−1@8TeV
Table 4: Uncertainties on the number of expected candidate events on each signal and background source for the systematic variations explained in Section 5. Systematic Signal W+jets W+HF+jets Jet energy scale < ±1% ±13% ±3% Jet energy resolution ±4% ±20% ±3% b-tagging efficiency ±5% ±1% ±1% c-tagging efficiency < ±1% ±3% ±20% Mistag rate < ±1% ±26% < ±1% Muon momentum scale < ±1% < ±1% < ±1% Muon identification ±1% ±1% ±1% Electron energy scale < ±1% < ±1% < ±1% Electron identification ±1% ±1% ±1% Missing transverse momentum < ±1% < ±1% < ±1% PDF ±3% ±4% ±8% W+jets modelling — < ±1% < ±1% Cross section — 24% 55% Systematic t¯ t single-top Z + jets Jet energy scale ±13% ±4% ±4% Jet energy resolution ±1% ±2% ±6% b-tagging efficiency ±5% ±5% ±4% c-tagging efficiency < ±1% < ±1% ±5% Mistag rate < ±1% < ±1% ±3% Muon momentum scale < ±1% < ±1% < ±1% Muon identification ±1% ±1% ±1% Electron energy scale < ±1% < ±1% < ±1% Electron identification ±1% ±1% < ±1% Missing transverse momentum < ±1% < ±1% ±3% PDF ±4% ±2% ±5% ISR/FSR ±3% ±5% — Cross section 8% 10% 24%
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
ATLAS-CONF-2013-063: tqg couplings, 14.2 fb−1@8TeV
Wb) [pb] → B(t ×
t → qg
σ 1 2 3 4 5 Posterior Density 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Preliminary ATLAS
= 8 TeV s
L dt = 14.2 fb
∫
Expected limit @ 95% C.L. Wb) < 2.2 pb → B(t ×
t → qg
σ Wb) [pb] → B(t ×
t → qg
σ 1 2 3 4 5 Posterior Density 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Preliminary ATLAS
= 8 TeV s
L dt = 14.2 fb
∫
Observed limit @ 95% C.L. Wb) < 2.5 pb → B(t ×
t → qg
σ
a) b)
]
[TeV Λ
ugt
κ 1 2 3 4 5
10 × ]
[TeV Λ
cgt
κ 2 4 6 8 10 12 14
10 ×
Observed Expected
Preliminary ATLAS Excluded region
= 8 TeV s
L dt = 14.2 fb
∫
ug) → B(t 5 10 15 20 25 30
10 × cg) → B(t 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22
10 ×
Observed Expected
Preliminary ATLAS Excluded region
= 8 TeV s
L dt = 14.2 fb
∫
c) d) Figure 7: a) Signal posterior probability density for the Asimov dataset and b) for the observed data sample as a function of the signal cross section times the t ! Wb branching fraction, c) upper limit on the coupling constants κugt/Λ and κcgt/Λ and d) on the branching fractions t ! ug and t ! cg.
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
CMS-PAS-TOP-14-003: tqγ couplings, 19.1 fb−1@8TeV
(GeV)
T
Photon P
50 100 150 200 250 300
Events / 10 GeV
100 200 300 400 500 600 700 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3712 Mean 81.56 RMS 36.62 mu_BDT__zjethist Entries 3712 Mean 81.56 RMS 36.62η Photon
1 2 3
Events / 0.4
50 100 150 200 250 300 350 400 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3639 Mean 0.03649 RMS 1.378 mu_BDT__zjethist Entries 3639 Mean 0.03649 RMS 1.378(GeV)
T
Muon P
20 40 60 80 100 120 140 160 180 200 220
Events / 13 GeV
100 200 300 400 500 600 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3625 Mean 60.14 RMS 31.29 mu_BDT__zjethist Entries 3625 Mean 60.14 RMS 31.29η Muon
1 2 3
Events / 0.4
50 100 150 200 250 300 350 400 450 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3639 Mean 0.02614 RMS 1.123 mu_BDT__zjethist Entries 3639 Mean 0.02614 RMS 1.123(GeV)
T
b-jet P
50 100 150 200 250 300
Events / 13 GeV
50 100 150 200 250 300 350 400 450 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3633 Mean 69.83 RMS 38.49 mu_BDT__zjethist Entries 3633 Mean 69.83 RMS 38.49η b-jet
1 2 3
Events / 0.4
50 100 150 200 250 300 350 400 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 4042 Mean 0.01399 RMS 1.198 mu_BDT__zjethist Entries 4042 Mean 0.01399 RMS 1.198Figure 2: Distributions of pT and η of the photon (top), muon pT and η (middle), and b-jet pT and η (bottom) after the final event selection and background estimations. The uncertainty band includes all sources of the uncertainties, although the dominant contribution is the statis- tical error on the normalization fit. ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
CMS-PAS-TOP-14-003: tqγ couplings, 19.1 fb−1@8TeV
Number of Jets
1 2 3 4 5 6 7 8
Events / 1
100 200 300 400 500 600 700 800 900 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3641 Mean 2.05 RMS 1.145 mu_BDT__zjethist Entries 3641 Mean 2.05 RMS 1.145b-Jet Discriminator
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Events / 0.05
100 200 300 400 500 600 700 800 900 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3637 Mean 0.2966 RMS 0.262 mu_BDT__zjethist Entries 3637 Mean 0.2966 RMS 0.262R (Photon,muon) Δ
1 2 3 4 5 6
Events / 0.42
100 200 300 400 500 600 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3640 Mean 2.61 RMS 0.7843 mu_BDT__zjethist Entries 3640 Mean 2.61 RMS 0.7843R (Photon,b-jet) Δ
1 2 3 4 5 6
Events / 0.42
100 200 300 400 500 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3639 Mean 2.701 RMS 0.7647 mu_BDT__zjethist Entries 3639 Mean 2.701 RMS 0.7647) γ Cos(W,
0.2 0.4 0.6 0.8 1
Events / 0.07
20 40 60 80 100 120 140 160 180 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3639 Mean) γ Cos(top,
0.2 0.4 0.6 0.8 1
Events / 0.07
20 40 60 80 100 120 140 160 180 200 220 240 BDT output = 8 TeV s ,
CMS Preliminary, 19.1 fb Data Other γ W W+jets ) 1 pb γ Signal(tu Stat) ⊕ Uncertainties (Syst
mu_BDT__zjethist Entries 3639 MeanFigure 3: Distributions of jet multiplicity and b-tagging discriminator (top), ∆R(µ, γ) and ∆R(b − jet, γ) (middle), and the cos(W, γ) and the cos(top, γ) (bottom) after the final event selection and background estimations. The uncertainty band includes all sources of the uncer- tainties, although the dominant contribution is the statistical error on the normalization fit. ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24
CMS-PAS-TOP-14-003: tqγ couplings, 19.1 fb−1@8TeV
γ tu
κ
0.01 0.02 0.03 0.04 0.05 0.06
) (pb) ν l → Br(w ×
γ tu
σ
0.02 0.04 0.06 0.08 0.1 0.12 0.14 Predicted 95% CL Observed Limit 95% CL Expected Limit Exp.Limit σ 1 ± Exp.Limit σ 2 ± = 8 TeV s ,
CMS Preliminary, 19.1 fb γ tc
κ
0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2
) (pb) ν l → Br(w ×
γ tc
σ
0.02 0.04 0.06 0.08 0.1 0.12 0.14 Predicted 95% CL Observed Limit 95% CL Expected Limit Exp.Limit σ 1 ± Exp.Limit σ 2 ± = 8 TeV s ,
CMS Preliminary, 19.1 fb
Figure 5: The 95% CL upper limit on the signal cross section as a function of κtuγ and κtcγ, as well as the predicted cross section calculated by Protos.
ghammad@cern.ch (Umons) Search for FCNC/H in the top sector 27/05/2014 24 / 24