Summary of EPS Conference 2013
Jimmy McCarthy
University of Birmingham
27/11/2013
The 2013 European Physical Society Conference on High Energy Physics Stockholm, Sweden, 18-24 July, 2013
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 1 / 44 Introduction Summary of EPS-HEP 2013 MANY results presented over 6 days This is a biased summary The conference: Stockholm, Sweden, 18-24 July, 2013 Highlights: Reception at City Hall Invited talk from Peter Higgs Conference dinner at Vasa Museum
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 2 / 44 700 physicists present:
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 3 / 44 EPS HEPP Prize 2013 The 2013 High Energy and Particle Physics Prize, for an outstanding contribution to High Energy Physics, is awarded to the ATLAS and CMS collaborations,“for the discovery of a Higgs boson, as predicted by the Brout-Englert-Higgs mechanism”, and to Michel Della Negra, Peter Jenni, and Tejinder Virdee,“for their pioneering and outstanding leadership roles in the making of the ATLAS and CMS experiments”.
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 4 / 44 Higgs Physics Contents
1 Higgs Physics
2 Top Physics
3 Heavy Ions
4 Flavour Physics 0 + − B(s) µ µ b →sll transitions Λ0→ Λη(′) b →
5 Conclusions
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 5 / 44 Higgs Physics Higgs Physics
New Boson discovered July 2012. Is it the Higgs Boson? Enough statistics now to start measuring.
Phys. Lett. B 716 (2012) 1
Phys. Lett. B 716 (2012) 30
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 6 / 44 Higgs Physics High statistics decay channels
CMS: MELA (angular analysis), FSR recovery, untagged + VBF
ATLAS Collaboration, arXiv:1307.1427 CMS PAS HIG-13-002
40 Data 2011+ 2012 ATLAS SM Higgs Boson H ZZ m =124.3 GeV (fit) H→ZZ* →4l 35 H s = 7 TeV ∫Ldt = 4.6 fb -1 Background Z, ZZ* = 8 TeV s = 8 TeV ∫Ldt = 20.7 fb -1 → Events/5 GeV Background Z+jets, t t Both experiments now have 30 Syst.Unc. 6.6 σ (4.4 σ exp.) > 6σ in this channel alone. 25 20 m = High resolution channel. 15 10 +0.6+0.5 mH = 124.3−0.5−0.3 GeV 5 0 100 150 200 250 6.7 σ (7.2 σ exp.) m4l [GeV]
10000 2 ATLAS 1.8 ATLAS Preliminary data syst. unc. 8000 Data 2011+2012 SM Higgs boson m =126.8 GeV (fit) gg →H NLO+PS ( POWHEG +PY8) + X H H γγ H 1.6 Bkg (4th order polynomial) [fb/GeV] X T gg →H NNLO+NNLL ( HR ES 1.0 ) + H
6000 p → 1.4 X Events / 2 GeV H = VBF + VH + t Ht
H γγ→ / d
4000 fid 1.2 σ H→ γγ , s = 8 TeV
High backgrounds. d -1 1 = 7 TeV s = 7 TeV Ldt = 4.8 fb L dt = 20.3 fb -1 2000 ∫ ∫ = 8 TeV s = 8 TeV Ldt = 20.7 fb -1 mH = 126.5 GeV 0.8 ∫ signal significance: Sensitive to spin. 500100 110 120 130 140 150 160 0.6 400 7.4 σ observed 300 4.3 σ expected 0.4 200 100 0.2 CMS show similar results. 0 0 1 2 3 -100 0 -200 100 110 120 130 140 150 160 Events - Fitted bkg OWHEG Some tension in differential m γγ [GeV] 2 Ratio to P 0 production spectra. 0 20 40 60 80 100 120 140 160 180 200 Particle level p [GeV] T γγ
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 7 / 44 Higgs Physics Associated production
Starting to add different production mechanisms into the mix. Associated production with a vector boson (VH). Observed in WH channel. Other mechanisms (i.e. VBF): searched still ongoing.
Adding VH(WW)
35 median expected
SM CMS preliminary ✦ expected ± 1 σ -1 A bit extra help from the VH(WW) in 3- σ L = 19.5 fb = 8 TeVs 30 expected ± 2 σ /
σ observed lepton (ATLAS+CMS), 4-lepton 25 CMS PAS HIG-13-009 (ATLAS), and lljj (CMS) final states 20 ✦ ATLAS: combination with the H(WW) 15 V(jj)H(WW) analysis: 10 95% CL limit on 95% CL ๏ 4.0 σ (3.8 σ exp.) significance at 5 mH = 125 GeVeV 110 115 120 125 130 135 140 Higgs mass (GeV) ATLAS-CONF-2013-075 SM SM 2 ATLAS Preliminaryliminary VH →VWW → 3 or 4 leptons observed 10 σ CMS preliminary σ
/ 2 / Obs. -1 10 → ν σ σ median expected VH 3l3 (shape-based) Exp. s = 7 TeV:∫ Ldt = 4.7 fb -1 expected ± 1 σ L = 4.9 fb -1 (7 TeV) + 19.5 fb -1 (8 TeV) ±1σ s = 8 TeV:∫ Ldt = 20.7 fb expected ± 2 σ ±2σ ν W(l )H(WW) + CMS PAS HIG-13-009 10 Z(ll)H(WW) 10 W(l ν)H(WW) 95% CL Limit on 95% CL limit on 95% CL
Greg Landsberg - Higgs Bosons in the SM and Beyond EPS 2013 Landsberg Greg 1 1
25 110 120 130 140 150 160 170 180 190 200 110 120 130 140 150 160 170 180 190 200 mH [GeV] Higgs mass [GeV] Slide J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 8 / 44 Higgs Physics Spin-Parity measurements
Spin-Parity of the SM model Higgs boson should be JP =0+. Test against various hypotheses: 0−, 1+, 1−, 2+.
CMS preliminary s = 7 TeV, L = 5.1 fb -1 s = 8 TeV, L = 19.6 fb -1
+ 0.25 ATLAS Data 0.1 0 → → - H ZZ* 4l P + 0 •1 J = 0 = 7 TeV s = 7 TeV ∫Ldt = 4.6 fb CMS data 0.2 P • 0.08 = 8 TeV s = 8 TeV ∫Ldt = 20.7 fb •1 J = 0
J = 1 states disfavoured by 0.15 Normalised to unity 0.06 Pseudoexperiments Landau/Yang. 0.1 0.04
Observation of H → γγ. 0.05 0.02
0 •15 •10 •5 0 5 10 15 H ZZ used to rule out 0 − q -30 -20 -10 0 10 20 30 P→ YE(( -2 × ln(L - / L +) 0 J =0 f (%) 0 qq CMS preliminary = 7 TeV, L = 5.1 fbs -1 = 8 TeV, L = 19.6 fbs -1
0+ 0.1 + ATLAS at 97.8% C.L. 2m(gg) CMS data (CL obs. = 0.6%) CMS at 99.8% C.L. 0.08 s Graviton-like JP =2+ ruled out. Probability density 0.06 0.04
ATLAS >99.9% (γγ + ZZ + 0.02
0 WW ) -30 -20 -10 0 10 20 30 -2 × ln(L / L +) YE(( + 0 CMS 99.4% (ZZ01(2%"34(6.,6(N(\!=NK\!(=*#GD#:I((YBZ[(+ WW ) 2m(gg)
Both experiments favour SM quantum numbers.
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 9 / 44 Higgs Physics
Signal Strength µ = σ/σSM
ATLAS (stat) Total uncertainty s = 7 TeV, L ≤ 5.1 fb -1 s = 8 TeV, L ≤ 19.6 fb -1 (sys) -1 mH = 125.5 GeV " 1 on ! Tevatron Run II, L $ 10 fb (theo) CombinedCombin ed CMCMS Preliminary m H = 125.7 GeV int + 0.23 arXiv:1307.1427 µ = 0.80 ± 0.14 2 - 0.22 p = 0.65 m =125 GeV/c H " !! SM H + 0.17 +0.33 - 0.13 ! = 1.55 + 0.17 Combined (68% C.L.)C.L. ) -0.28 - 0.12 H → bb + 0.35 arXiv:1307.1427 Single channelchann el H " ZZ* " 4l - 0.32 µ = 1.15 ± 0.62 + 0.20 +0.40 - 0.13 ! = 1.43 + 0.17 -0.35 - 0.10 H! ## + 0.20 arXiv:1307.1427 H → ττ H " WW* " l l - 0.21 + 0.23 µ = 1.10 ± 0.41 +0.31 - 0.19 + - ! = 0.99 + 0.15 H! W W -0.28 - 0.09 Combined + 0.13 arXiv:1307.1427arXi v:13 07.1 427 - 0.14 H → γγ + - H! !!" , ZZ*,ZZ *, WWW*W* + 0.17 H! +0.21 - 0.13 µ = 0.77 ± 0.27 ! = 1.33 + 0.12 -0.18 - 0.10
ATLAS-CONF-2013-079S-CONF-2013- 079 H → WW VH ! Vb b W,Z H " b b "0.5 µ = 0.68 ± 0.20 Preliminary "0.4 ! = 0.2 +0.7 ,%-( -0.6 <0.1 012345678910 H " (8TeV: 13 fb -1 ) ATLAS-CONF-2012-160S-CONF-2NF-2 012- 160 H → ZZ Best Fit ( ! Br)/SM Preliminary µ = 0.92 ± 0.28 ! = 0.7 +0.7 - 0.6 0 0.5 1 1.5 2 2.5 = 7 TeV s = 7 TeV Ldt = 4.6-4.8 fb -1 -0.5 0 0.5 1 1.5 2 Best fit σ/σ ( SM = 8 TeV s = 8 TeV Ldt = 13-20.7 fb -1 Signal strength ( !)
• 2#I8C/%A( µ(!(.%'*(9GG3"9GO( 83*( /#('*"#/F($+O'CG'(I#&J9&#/ M( – N!N (g γγX( $$q( &A)( %%q h(((((((((((((((((( µ (g w`yy((v`xv h( (` Z1Y[ B1Zl( C/G:3AC/F( 88( 9/A( ττ a( – = ((g γγ, ττX( '' X( $$q( &A)( %%q h((((((( µ (g v`v((v`w h( – !4#N! (g '' X( γγ, ττX( $$q h(((((((((((( µ (g w`((v`v h(( =B@C&H'90( S6G5( (^644F('BFBA( 0TC0(G&HBAY( N((QE&(U (r(w( (
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J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 10 / 44 Top Physics Contents
1 Higgs Physics
2 Top Physics
3 Heavy Ions
4 Flavour Physics 0 + − B(s) µ µ b →sll transitions Λ0→ Λη(′) b →
5 Conclusions
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 11 / 44 Top Physics Top Pair Production
LHC is a top factory:
ATLAS: σ ¯ = 232 2(stat) 31(syst) 9(lumi) pb tt ± ± ± t t ATLAS data /dy t t -1 NLO (MCFM) σ 1 L dt = 2.05 fb
d ∫ t ALPGEN t
σ MC@NLO Differential cross-sections measured: 1/ Consistent with theoretical models. 10 -1
Vs. kinematics of 1.2 1 -3 -2 -1 0 1 2 3
Theory/Data y tt Mass measurements - decay products Good agreement ATLAS measured using a 3D fit to reco reco reco Mtop , MW , and Rlb . CMS using a lifetime-based technique.
ATLAS: Mtop = 172.31 0.23(stat) 0.27(JSF) 0.67(bJSF) 1.35(syst) GeV ± ± ± ± CMS: Mtop = 173.5 1.5(stat) 1.3(syst) 2.6(pT) GeV ± ± ± J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 12 / 44 Top Physics Spin Correlations
• Spins of top and anti-top are correlated in SM.
• Short top quark lifetime ( ∼ 5 × 10 −25 s) means spin information is carried on to decay products. • Measure fraction of SM-like 900 data ATLAS events, f SM , using template fit t (SM)t -1 Events 800 tt (uncorrelated) Ldt = 2.1 fb single top ∫ to ∆φ(ℓℓ ) distribution. 700 Z/ γ*+jets diboson SM → 600 fake leptons - f = 0 no correlations. SM 500 - f = 1 → correlations (SM). 400 SM +0 .27 ATLAS: f = 1 .30 ± 0.14 −0.22 → 5.1σ 300 Phys. Rev. Lett. 108, 212001 (2012) 200 SM CMS: f = 0 .74 ±0.08( stat )±0.24( syst ) 100 CMS-TOP-12-004 0 SM 0 0.5 1 1.5 2 2.5 3 D0: f = 0 .85 ± 0.29 → 3.1σ φ∆ Phys. Rev. Lett. 108, 032004 (2012)
SARA STRANDBERG , S TOCKHOLM UNIVERSITY P. 21 EPSHEP 2013, S TOCKHOLM , J ULY 22, 2013 J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 13 / 44 Top Physics Single Top Production
Single-top production occurs in several channels. t-channel production already observed at Tevatron and LHC. New: Evidence for s-channel production at D0. New: Observation of Wt-channel process at CMS. (a) -1 5 DØ 9.7 fb 1 SD 2 SD 50 4 (b) DØ 9.7 fb -1 3 SD 100 Data ATLAS Data 40 tb JES uncertainty -1 Wt tqb 3 80 ∫ L dt = 2.05 fb tt W+jets WW/ZZ/WZ = 7 TeVs Z(ee/ µµ )+jets Z+jets/Diboson Z( )+jets 30 Dilepton 1 jet ττ Events / 0.03 60 Fake dileptons tt Measurement Multijets tqb cross section [pb] 2 SM 40 20 Four generations Top-flavor20 10 1 Top pion Yield [Events/0.04] 0 FCNC -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 BDT output 0 0 0.7 0.8 0.9 1 0 1 2 3 4 5 +5 .5 ± ± Ranked s-channel discriminant σ = 23 .4−5.4 pb tb cross sectionσ = 16 .8 [pb]2.9( stat ) 4.9( syst ) pb 6.0σ significance 3.3σ significance CMS-PAS-TOP-12-040 Phys. Lett. B 716, 142 (2012) Also lots of activity looking for new physics with top quarks: CP Violations, FCNC, Baryon Number Violation etc. J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 14 / 44 Heavy Ions Contents
1 Higgs Physics
2 Top Physics
3 Heavy Ions
4 Flavour Physics 0 + − B(s) µ µ b →sll transitions Λ0→ Λη(′) b →
5 Conclusions
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 15 / 44 Heavy Ions Heavy Ion Collisions
Recently results from LHC compare Pb-Pb and p-p collisions. Looking for signatures of new states of matter e.g Quark Gluon Plasma (QGP) Uses p-p collisions as a control channel. Problem is big differences between Pb-Pb and p-p collisions. Recent run at LHC in 2013 dedicated to investigating p-Pb collisions. Disentangle initial state effects. Highlights any effects to to cold nuclear matter. Lets LHCb into the Heavy Ion game! Collide p-Pb and Pb-p to get forward and backward measurements.
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 16 / 44 Heavy Ions Baryon Anomaly
0 Enhanced ratio of Λ/KS at medium pT. Observed in Pb-Pb collisions. Also observed at RHIC. More enhanced for more central collisions.
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J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 17 / 44 Heavy Ions Nuclear Modification Factor
Yield in AA 1 RAA = Yield in pp × Ncoll
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J. McCarthy (University"=>&)?34??@3AB)3=+0$$$$$$$$$$ of Birmingham) ,-"$.,-/$.0&12$345)/$6782$Summary of EPS 2013 !! /$ !"#$ 27/11/2013 18 / 44 Flavour Physics Contents
1 Higgs Physics
2 Top Physics
3 Heavy Ions
4 Flavour Physics 0 + − B(s) µ µ b →sll transitions Λ0→ Λη(′) b →
5 Conclusions
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 19 / 44 − Flavour Physics B0 → µ+µ (s) Contents
1 Higgs Physics
2 Top Physics
3 Heavy Ions
4 Flavour Physics 0 + − B(s) µ µ b →sll transitions Λ0→ Λη(′) b →
5 Conclusions
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 20 / 44 − Flavour Physics B0 → µ+µ (s) 0 + B µ µ− (s) → LHCb and CMS both presented results in the search for these rare decays.
Will concentrate on details of LHCb analysis C 5 ^NN2B6@?D6>D:2<C:D:F6@B?36C7?B+9IC:4C 6I?>5-( 276G
− b t 0 Interesting decays: 6H2=@<6C Z 0, H,h0 ... µ 0 + + B W , H # ( , d/s C 5 ^NN`D2> S2>5=# FCNC process: forbidden at tree level. t µ+ d/s ''&,#- '
New physics/particles enter via the loops. + ~+ b W , χ + (--( , C 5 ^NN`D2> S µ Theoretically very clean. 0 ~ ~ B ++0.!'%0, t,c,u q l ν 0 d/s |Vts| > |Vtd| =⇒ B decay supressed µ− '6@D?AE2B;Cd/s − ~− W , χ high sensitivity to models with extended Higgs-boson /&",)( sectors (" #,!)-#,#()( -%$#(#+ -&)(-)* #& %.). , 0 )%" (+)($ .%0, #/ Branching fractions predicted in SM using Lattice QCD:
0 + − −9 (B µ µ )SM = (3.57 0.9) 10 B s → ± × 0 + − −10 (B µ µ )SM = (1.07 0.1) 10 B → ± ×
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 21 / 44 − Flavour Physics B0 → µ+µ (s) LHCb Analysis
0 + − LHCb presented first evidence (3.5σ) for Bs µ µ based on 2011 data. Now analysing full 3 fb−1 2011 + 2012 dataset.→ Analysis performed blind. Using a Boosted Decision Tree (BDT). Uses kinematic and geometric variables. Trained using Monte Carlo calibrated to data. Unbinned maximum likelihood fit performed in bins of BDT response.
vs
+ – Bs→µ µ trained with MC calibrated on B0→µ +µ–
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 22 / 44 − Flavour Physics B0 → µ+µ (s) Normalisation
Two normalisation channels used to control systematics. − B+ → J/ψ(µ+µ )K + − B0 → K +π Use these to measure relative branching fractions.
ǫRECO×ǫSEL ǫTRG N cal cal cal fcal sig N = cal ǫRECO×ǫSEL ǫTRG f N = α(s) sig B B × sig sig × sig × d(s) × cal ×
Reco and sel efficiencies calculated from Monte Carlo, cross checked on data. Trigger efficiencies calculated from data sample of J/ψ µ+µ−. → fd 0 + − dominant systematic for Bs µ µ . fs → α measured for each control channel and averaged:
−11 αs = (9.41 0.65) 10 ± ×
α = (2.4 0.09) 10−11 ± ×
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 23 / 44 − Flavour Physics B0 → µ+µ (s) Results from LHCb )
2 16 c 14 LHCb 12 BDT>0.7 -1 UML fit to data, integrated over last 3 10 3 fb BDT bins: 8 6 Significance of signal = 4.0σ Candidates / (44 MeV/ 4 2 0 5000 5500 2 mµ+µ [MeV/c ]
0 + − +1.1 +0.3 −9 (B µ µ )=(2.9− (stat) (syst)) 10 B s → 1.0 −0.1 × Significance of the B0 signal is only 2.0σ. 0 + − +2.4 +0.6 −10 (B µ µ )=(3.7− (stat)− (syst)) 10 B → 2.1 0.4 ×
Use CLs method to place an upper limit on the branching fraction:
(B0 µ+µ−) < 6.3 (7.4) 10−10 at 90% (95%) CL B → ×
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 24 / 44 − Flavour Physics B0 → µ+µ (s) Results from CMS
CMS -- L L = = 5 20fb -1 fb s-1 = s7 =TeV, 8 TeV L = 20- Endcap fb -1 = 8 TeVs
50 0.33 < BDT < 0.45 data data 8 full fullPDF PDF 0 0→+ - + - Bs→Bµs µµ µ 0 0+ - + - 7 B →Bµ→µµ µ combinatorial bkg 40 combinatorial bkg yield cross checked on independent data set semileptonicsemileptonic bkg bkg 6 peakingpeaking bkg bkg
305 CMS employs a similar analysis strategy. Events / ( 0.04 GeV ) 4 20 Significance of signal = 4.3σ 3
2 10 S/(S+B) Weighted Events / ( 0.04 GeV) 1
0 4.9 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 m µµ (GeV)
0 + − +0.9 +0.6 −9 (B µ µ )=(3.0− (stat) (syst)) 10 B s → 0.8 −0.4 × Significance of the B0 signal is only 2.0σ. 0 + − +2.1 −10 (B µ µ )=(3.5− ) 10 B → 1.8 ×
Use CLs method to place an upper limit on the branching fraction: (B0 µ+µ−) < 1.1 10−9 at 95% CL B → × J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 25 / 44 − Flavour Physics B0 → µ+µ (s) Combined results
Very quick work from LHCb and CMS to combine results. LHCb-CONF-2013-012 Haven’t combined significance of signal properly, but clearly > 5σ No combined limit on B0 µ+µ−. → (B0 µ+µ−)=(2.9 0.7) 10−9 B s → ± × 0 + − +1.6 −10 (B µ µ )=(3.6− ) 10 B → 1.4 × d → B s →
adapted from arXiv:1012.3893
What does this mean for SUSY?
J. McCarthySignificantly (University of constrains Birmingham) parameter spaceSummary of of EPS 2013 27/11/2013 26 / 44 Flavour Physics b → sll transitions Contents
1 Higgs Physics
2 Top Physics
3 Heavy Ions
4 Flavour Physics 0 + − B(s) µ µ b →sll transitions Λ0→ Λη(′) b →
5 Conclusions
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 27 / 44 Flavour Physics b → sll transitions 0 + B K ∗µ µ− →
b s transitionsc are FCNC. New→ physics can alter angular correlations.
Altmannshofer et al. (2008)
J. McCarthy")#%!(#!"$* (University of Birmingham) Summary +-0*10**451*#!"$* of EPS 2013 27/11/2013 28 / 44 Flavour Physics b → sll transitions Results I
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 29 / 44 Flavour Physics b → sll transitions Results II
Forward-backward asymmetry of particular interest. Crossing point sensitive to new physics. LHCb present first measurement. q2 =4.9 0.9 GeV2/c2 0 ±
q2 SM =3.95 0.38 GeV2/c2 0 ±
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 30 / 44 Flavour Physics b → sll transitions New Angular Variables
Theorists propose new angular variables Slightly less dependant on form factor models.
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 31 / 44 Flavour Physics b → sll transitions Results III Results for new observables NEW LHCb collaboration (1fb -1 ), LHCb-PAPER-2013-037
LHCb LHCb Preliminary Preliminary
′ Some tension between measurement and theory for P5 ≈ 2.8σ when consider 24 independant measurements.
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 32 / 44 Flavour Physics b → sll transitions 0 + Λ Λµ µ− b → Other b s decays available. 0 → 0 + − 0 + − 0 + − B → K µ µ , Bs → φµ µ ,Λb → Λµ µ ... 0 + − First results from LHCb for Λb Λµ µ shown: 0 → Λb → ΛJ/ψ as control channel. Differential branching fraction measured in q2 bins. Total of 80 events in all bins. (Λ0 Λµ+µ−)=(0.96 0.16(stat) 0.13(syst) 0.21(norm)) 10−6 B b → ± ± ± × ψ
Predictions from Detmold et al. (2012) J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 33 / 44 0 → (′) Flavour Physics Λb Λη Contents
1 Higgs Physics
2 Top Physics
3 Heavy Ions
4 Flavour Physics 0 + − B(s) µ µ b →sll transitions Λ0→ Λη(′) b →
5 Conclusions
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 34 / 44 0 → (′) Flavour Physics Λb Λη Introduction
Search for Λ0 Λη′ and Λ0 Λη. b → b → Investigate the phenomena of η–η′ mixing. η(′) mass eigenstates described by mixing of flavour eigenstates. η cos φp sin φp ηq | ′i = − | i . η sin φp cos φp ηs | i | i 1 ηq = uu + dd | i √2| i
ηs = ss | i | i
Introduce gluonic component to η′ wavefunction.
η cos φp ηq sin φp ηs | i≈ | i− | i ′ η cos φG sin φp ηq + cos φG cos φp ηs + sin φG gg . | i≈ | i | i | i
Has interesting consequences for branching fractions.
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 35 / 44 0 → (′) Flavour Physics Λb Λη Branching Fractions
Extra Feynman Diagrams available for η′ decays =⇒ interference!
(B0 K 0η′) = (66 4) 10−6 B → ± × 0 0 +0.27 −6 (B K η)=(1.23− ) 10 B → 0.24 ×
Measure relative branching ratio of B X η′ to B X η decays. → → Many different decays needed to measure φp and φG No baryonic decay yet observed.
Expected: (Λ0 Λη(′)) (2 40) 10−6 arxiv:hep-ph/0305031 B b → ≈ − ×
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 36 / 44 0 → (′) Flavour Physics Λb Λη Analysis
Based on LHCb-CONF-2013-010 Preliminary results presented. − Using 2012 dataset (2 fb 1). 0 ′ Search for Λb → Λη . 0 0 ′ Using B → KS η as control channel.
Reconstruct η′ π+π−γ, K 0 π+π− Λ pπ− → S → → Selection is cut-based preselection + BDT. PID selection to separate π K and p. Data reweighted by PID efficiency. 0 Selection different depending where the KS /Λ decays. Upstream of VeLo: Long-Long selection (LL). Downstream of VeLo: Down-Down selection (DD). Selection optimised separately for two categories.
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 37 / 44 0 → (′) Flavour Physics Λb Λη Boosted Decision Tree (BDT)
Takes many variables which discriminate between signal and background Combines them into one powerful discriminant (BDT response) Trained using signal MC and data sidebands to model the background Particle Variables 0 0 2 2 2 B (Λb) pT , log(FD χ ), log(τχ ), log(1 - DIRA Angle), Decay Vertex χ 0 0 2 2 KS (Λ ) p, log(IP χ ), log(FD χ ) ′ 2 η pT , log(IP χ ) γ log(ET ) BDTResponse(LL) BDTResponse(DD)
TMVA overtraining check for classifier: BDT TMVA overtraining check for classifier: BDT
5 Signal (test sample) Signal (training sample) dx dx
5 / / Background (test sample) Background (training sample) 4 Kolmogorov-Smirnov test: signal (background) probability = 0.352 ( 0.55) Kolmogorov-Smirnov test: signal (background) probability = 0.877 (0.968) 4 (1/N) dN (1/N) dN
3 3
2 2
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0 U/O-flow (S,B): (0.0, 0.0)% / 0 U/O-flow (S,B): (0.0, 0.0)% / -0.6 -0.4 -0.2 0 0.2 0.4 -0.6 -0.4 -0.2 0 0.2 BDT response BDT response J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 38 / 44 0 → (′) Flavour Physics Λb Λη Normalisation
Measuring ratio of branching fractions: 0 0 ′ 0 0 0 0 + − B(Λ → Λ η ) NS (Λ ) ǫacc (B ) ǫtot (B ) f 0.5 × B(K → π π ) R b b d S = 0 0 ′ = 0 × 0 × 0 × × 0 − B(B → K η ) NS (B ) ǫacc (Λb) ǫtot (Λb) fΛb B(Λ → pπ )
Production fractions measured by LHCb
Function of pT Largest systematic uncertainty (27%)
fΛb = (0.404 ± 0.109) × [1 − (0.031 ± 0.005) × pT (GeV)] (fu + fd ) f f Λb = 0.319 ± 0.086 =⇒ d = 1.57 ± 0.42 (fu + fd ) fΛb
Ratio of selection efficiencies (ǫ) measure using Monte Carlo Second dominant systematic uncertainty (22%) Easily improved with more Monte Carlo
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 39 / 44 0 → (′) Flavour Physics Λb Λη Mass fits to B0
Selection applied to data and fit performed to reweighted B0 mass.
50 ) ) 2 2 c c 60 LHCb Preliminary Data LHCb Preliminary Data Fit Model Fit Model 0 40 0 B Ks ' B Ks ' 50 Combinatoric Background Combinatoric Background
40 30
30 20 Candidates / ( 30 MeV/ Candidates / ( 30 MeV/ 20 10 10
0 0 4900 5000 5100 5200 5300 5400 5500 5600 5700 5800 4900 5000 5100 5200 5300 5400 5500 5600 5700 5800 M(K ’) ( MeV/ 2 ) M(K ’) ( MeV/ 2 ) s c s c N(LL)=125 ± 13(14.8σ) N(DD)=75 ± 12(11.7σ)
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 40 / 44 0 → (′) Flavour Physics Λb Λη 0 Mass fits to Λb
After unblinding, no significant signal is observed. All parameters in signal model fixed to MC values. Yield left to float. Number of events extracted from fit used to place a limit on branching fraction.
) ) 2 2 c 14 LHCb Preliminary c LHCb Preliminary Data 12 Data 12 Fit Model Fit Model Combinatoric Background 10 Combinatoric Background 10 8 8 6 6 Candidates / ( 50 MeV/ Candidates / ( 50 MeV/ 4 4
2 2
0 0 5000 5200 5400 5600 5800 6000 6200 5000 5200 5400 5600 5800 6000 6200 2 2 M( ’) ( MeV/c ) M( ’) ( MeV/c ) N(LL)=1 N(DD)=–3
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 41 / 44 0 → (′) Flavour Physics Λb Λη Limits
Use Feldman-Cousins method and information from the fit to set an upper limit on branching fraction. Absolute branching fraction using (B0 K 0η′)=66 10−6. B → S × B 0 → 0 ′ (Λb Λ η ) −2 R = ′ < 9.6 10 at 90% CL B(B0→K 0η ) ×
(Λ0 Λ0η′) < 6.3 10−6 at 90% CL B b → ×
c.f. Theoretical prediction:
Expected: (Λ0 Λη(′)) (2 40) 10−6 arxiv:hep-ph/0305031 B b → ≈ − ×
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 42 / 44 Conclusions Contents
1 Higgs Physics
2 Top Physics
3 Heavy Ions
4 Flavour Physics 0 + − B(s) µ µ b →sll transitions Λ0→ Λη(′) b →
5 Conclusions
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 43 / 44 Conclusions Conclusions
All measurements are consistent with Standard Model predictions
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 44 / 44 Back-Up Slides
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 45 / 44 spectrum is harder, the results may be biased ATLAS-CONF-2013-072 1.2 122 ATLAS ATLAS Preliminary data syst. unc. [fb] Preliminary φ∆ X 1 gg →H NLO+PS ( POWHEG +PY8) + H 10 data syst. unc. [fb/GeV] X / d gg →H NLO+PS ( POWHEG +PY8) + X H T gg →H+1j NLO+PS ( MINLO PHJ+ Y8) + H fid p σ gg →H+1j NLO+PS ( MINLO PHJ+ Y8) + X H 0.8 X H = VBF + VH + t Ht d 8 / d
fid X H = VBF + VH + t Ht
σ H→ γγ , s = 8 TeV d 0.6 6 ∫ L dt = 20.3 fb -1 H→ γγ , s = 8 TeV ∫ L dt = 20.3 fb -1 0.4 4
0.2 2
0 0 3 OWHEG OWHEG 2 5 Ratio to P Ratio to P 1
0 0 0 20 40 60 80 100 120 140 0 0.5 1 1.5 2 2.5 3 Particle level p [GeV] Particle level φ∆ T,jet1 jj
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 46 / 44 Slide 23 Greg Landsberg - Higgs Bosons in the SM and Beyond - EPS 2013 ✦ ✦ ✦ cross-check ine channels (alsoasa for thesame-flavor and cut-basedanalysis vs. M CMS: 2DanalysisinM distribution ATLAS: fittotheM resolution channel High-yield, low- ๏ ๏ .MCrh Uiest fBirmingham) of (University McCarthy J. the ee,e and 2-jetcategories;in Search donein0-,1-, mass) (dilepton transverse variables: M Most discriminating channels T forthee µ , and ll andM µ channel channel µ µµ ) T
H(WW T ll
Data - Bkg. Events / 10 GeV Data / bkg. Events / 10 GeV 100 200 300 400 500 600 700 800800 100 -20 ATLAS Collaboration 100 200 300 400 500 600 700 20 40 60 80 0.6 0.8 1.2 1.4 0 1 arXiv:1307.1427 08 0 2 4 6 8 0 2 4 260 240 220 200 180 160 140 120 100 80 60 260 240 220 200 180 160 140 120 100 80 60 H ATLAS ATLAS → =8TeV =7TeV s s =8TeV s WW* Data2012 0101020250 2 200 200 150 150 100 100 50 → ∫ ∫ l ν Ldt=20.7fb Ldt=4.6fb l ν ∫ Ldt=20.7fb +0/1jets → SMsig.+bkg. -1 -1 H Bkg.subtracteddata SMHiggsbosonm → -1 WW* l Z/ W+jets SingleTop OtherVV t WW m SMHiggsboson Totalsig.+bkg. Data2011+2012Da → t γ Z/ WW m SingleTop OtherVV W+jets t SMHiggsboson Totalsig.+bkg. Data2012 e * t H ν ν γ =125GeV µ * H H ν m =125GeV =125GeV +0jets m T [GeV] ll [GeV] l ν
2 ) 2 CMS PAS HIG-13-003 data / MC events / 10 GeV/c 1000 0.5 1.5 2.5 data / MC events / 10 GeV/cV/c 200 400 600 800 0 2 1 0.5 1.5 2.5 100 150 200 250 0 50 0 0 300 200 300 100 250 200 150 0 100 50 0 0 2 1 0 0101020250 200 150 250 100 200 50 150 100 0 50 0 VV H125 data stat. Z/ Z/ VV H125 data stat. γ * γ ⊕ * syst. ⊕ syst. 100 WW T op W+jets m WW T op W+jets m H =125 GeV H =125 GeV 200 CMS Preliminary = 8 8 TeV,= fbsL 19.5 = CMS Preliminary = 7 7 = TeV, Lfbs 4.9 = = 8 8 = TeV, fbsL 19.5 = = 7 7 = TeV, Lfbs 4.9 = m m ll- E m m T ll- T [GeV/cm E [GeV/c ll ll T [GeV/c [G [GeV/c 0-jet e 0-jet e µ -1 µ -1 -1 -1
2 2 2 2 ] ] ] ] umr fES2013 EPS of Summary 71/034 44 / 47 27/11/2013 Slide 31 Greg Landsberg - Higgs Bosons in the SM and Beyond - EPS 2013 ✦ ✦ ✦ ✦ ✦ reconstruction Benefits significantlyfrom particle-flow (SVFIT) with~20%resolution Optimized Also includeVH( Updated tofullstatistics;basedone and 2-jet(VBF)categories Analysis isdoneseparatelyin0-,1-, μμ CMS PAS HIG-13-004 ๏ ๏ .MCrh Uiest fBirmingham) of (University McCarthy J. , e τ 1- and2-jetcategoriesare notsplit on thep each splitintwo,depending 0- and1-jetcategoriesare h τ τ h h doesn’t use0-jetcategoryandthe , μ τ h T ττ , and ofthe massreconstruction ττ τ h τ ) channels τ -decay products h H( channels normalization from controlnormalization shape from simulation;shape regions (10-20% syst.) (10-20% regions Dominated by W+jets;Dominated ττ ) in CMSin ) iue9 obndosre n expected and observed Combined 9: Figure μ w w ,
S/B Weighted dN/dm [1/GeV] ττ 1000 200 400 600 800 0 0 0 300 200 100 0 CMS Preliminary, CMS simulated simulated Embedding (replace µ with µ with (replace Embedding e µ normalization from Z(µµ) normalization e, τ h QCD: from SS sample , µ τ h , τ h τ h (5% syst.)(5% (10% syst.)(10% τ s m in Z(µµ) sample); Z(µµ) sample); in = 7-8 TeV, 7-8 = Lfb 24.3 = 20 40 0 itiuin o h e , the for distributions 0 150 100 electroweak t observed QCD Z H(125 GeV) t m ττ→ H(125 GeV) Bkg. Uncertainty Data -Background m ττ [GeV] ττ [GeV] -1 → →
ττ ττ umr fES2013 EPS of Summary 71/034 44 / 48 27/11/2013 Slide 35 Greg Landsberg - Higgs Bosons in the SM and Beyond - EPS 2013 ✦ ✦ ✦ 95% CL limit on (H !Z )/ (H !Z ) SM Decay canbeenhanced/suppressed independentlyofH( leptonic branchingfractionoftheZ Not sensitivetotheSMHiggsboson(yet),setfollowinglimits: Similar branchingfractiontoH( 10 15 20 25 30 35 40 45 ๏ ๏ ๏ 2 2 3 3 4 4 150 145 140 135 130 125 120 0 5 .MCrh Uiest fBirmingham) of (University McCarthy J. ATLAS: Sensitive tonewphysicsvialoops CMS: # # Ldt=20.7fb Ldt=4.6fb μ -1 <10@95%CL(10expected) , -1 μ , <18.2@95%CL(13.5expected) = 7 TeVs = 8 TeVs ATLAS-CONF-2013-009 H(Z ATLAS Expected Observed ! ! Preliminary Preliminary 1 2
γ m H [GeV] ) Results ) γγ ), butanadditionalpricetopayforthe
95% CL limit on σ/σSM 10 15 20 25 30 35 40 2 2 3 3 4 4 5 5 160 155 150 145 140 135 130 125 120 0 5 CMS S to appearonthearXivtomorrow s s = 7 TeV, =7TeV,L5.0fb= 7 5.0 L fb CERN-PH-EP-2013-113 CMS Collaboration H -1 γγ → g Z ) Expected Observed Expected s s γ = 8 TeV, 8 19.6L fb =8TeV,L19.6fb= ± ± m 2 1 H σ σ (GeV) -1 umr fES2013 EPS of Summary 71/034 44 / 49 27/11/2013 Slide 36 Greg Landsberg - Higgs Bosons in the SM and Beyond - EPS 2013
95% CL Limit on µ ✦ ✦ ✦ First search hasbeendonealready byATLAS Requires verylarge statisticsforobservation:astrong caseforHL-LHC Observing H( universal couplingsoftheHiggsboson 10 20 30 40 50 60 70 0 ๏ ๏ .MCrh Uiest fBirmingham) of (University McCarthy J. SM: Br(H SM: Br(H 1 1 2 2 3 3 4 4 150 145 140 135 130 125 120 115 110 ATLAS Sets limit N.B. Couplingtocharmisveryhard toprobe ± ± Bkg. Expected Observed 2 1 σ σ ATLAS-CONF-2013-010 Preliminary → μ μμ <9.8(8.2expected)@95%CL µµ) = 2x10 ) decaymaybetheonlywaytoprove non-flavor- ∫ H( Ldt=20.7fb H = 8 8 = TeVs → µ + -4 µ µµ - -1 m H [GeV] ) Results )
Events / 0.5 GeV 10 10 10 10 10 10 10 10 10 10 2 3 4 5 6 7 8 9 ∫ ATLAS 01010101010200 180 160 140 120 100 80
s L = 14 TeV
dt =3000fb Preliminary (Simulation) ATLAS-PHYS-PUB-2012-004 -1
Events - Bkg / 2 GeV -5000 5000 0 1 2 3 4 150 140 130 120 110 100 0 gg Z t WW t → → →
→ µ H µ µ ν
µ X → ν µ µ
ν ν µ µ X , m H m =125 GeV µ µ [GeV] umr fES2013 EPS of Summary 71/035 44 / 50 27/11/2013 Slide 38 Greg Landsberg - Higgs Bosons in the SM and Beyond - EPS 2013 ✦
Data/MC Events 10 20 30 40 50 60 0 2 1 New analysis;supersedesrecent publication arXiv:1303.0763basedon5+5fb Lepton + 08-. 04-. . . 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 ๏ ๏ ๏ ๏ 08-. 04-. . . 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 .MCrh Uiest fBirmingham) of (University McCarthy J. CMS Search in ttH(bb+in Search CMS t EWK (1.4) t t H125 (8.3t ≥ +bt +lf(71.1)t 6 jets+ each jetandb-taggedmultiplicity Signal extractionviaBDTs; separateBDTs for b-tagged jets H( tagged jetsrequired forthettH(bb)search tt decaysare reconstructed inthelepton+jetsanddileptonchannel;2ormore b- channel (8TeV only) Updated tothefull2012statistics(7TeV notreanalyzed) and addedthe (78.2)b ττ ≥ × 30) ≥ ) decaysare lookedforin 6 jets, 6 b-tags4 CMS Preliminary 4 b-tags Lepton + Data (260) single t(7.3) t +ct (51.8)c ≥ 6 jets+ = 8 8 TeV,= fbsL 19.4 = MVAoutput ttH(bb) Sum MC(249.0) t t + W,Z + 5.8)t ( +b(33.3)t ≥ 4 b-tags -1
Events
Data/MC 100 120 140 160 180 200 20 40 60 80 0 2 1 08-. 04-. . . . 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 08-. 04-. . . . 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 Dilepton+ τ ≥ ≥ h 3 3 b-tags 3 jets, t t t EWK (40.4) τ H125 (11.2x65.7)t H125 (288.7)t +bt h ≥ (79.9)b 3 jets+ channel,withttdecayinginlepton+jets,1or2 ≥ 3 b-tagsCMSPreliminary Data (774.0) t t +b(148.6)t(11.9)t V + nary ttH(bb) s BDT output = 8 8 8 = = TeV,TeV, fb fbs LL 19.45 19.45 = = Sum MC(733.7) t single t(17.3) +ct CMS PAS HIG-13-019 (146.9)c -1
Data/MC Events 10 15 20 25 30 0.5 1.5 2.5 5 2 1 1-. 06-. 020020406081 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 1-. 06-. 020020406081 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 τ h
τ h + + Collisions Z +jets t ≥ ≥ 6 jets + 2 b-tags, CMS Preliminary, CMS CMS b-tags, b-tags, 2 2 + + jets jets 6 t ≥ 6 6 jets, 2 b-tags Bkg. err. Bkg. single t/ WW,ZZ WZ, ττ Prelimin t decay ttH( ττ BDTresponse t t W +jets H(125) (t +W/Zt = 8 8 = TeV,L fbs 19.5 = 8 8 TeV,L fb 19.5 = ττ × 100) ) -1 ) -1 umr fES2013 EPS of Summary 71/035 44 / 51 27/11/2013 Slide 40 Greg Landsberg - Higgs Bosons in the SM and Beyond - EPS 2013 ✦ ✦ ✦
95% CL limit on σ/σSM Closing ontheSMHiggsbosonsensitivity! (once theanalysisisupdated) channels are addedandcombinedwithATLAS Would improve evenmore whenadditional CMS combinedresults: ๏ ๏ 10 1 1 2 2 3 3 140 135 130 125 120 115 110 4 0 2 6 8 .MCrh Uiest fBirmingham) of (University McCarthy J. CMS preliminaryb and canbemovedinto“visible”categoryofmytalk! Soon tobecomethe6thof“big”channels μ <3.4(2.7expected) ttH(125) injected Observed Expected Expected , b ± ± ττ , 2 1 ttH CombinationttH γγ σ σ ted CMS PAS HIG-13-019 CMS PAS HIG-13-015
and arXiv:1303.0763 = 7 7 = TeV,L fbs 5.0 = -1 ; = 8 8 = TeV,L fbs 19.5 = m H (GeV) -1
ttH( new - brand news Breaking ATLAS ATLAS-CONF-2013-080 ttHtH t Ht 95% CL limit on / SM γγ 10 15 20 25 30 35 40 0 5 ) 8 ) 8 TeV result: 95% CL Limit on /
2 2 2 2 2 130 128 126 124 122 120 SM 10 20 30 40 50 30 0 1 1 2 2 3 3 140 135 130 125 120 115 110 ATLAS-CONF-2012-135 A TLAS ! Expected ! Observed 2 1
Observed (CLs) ! ! ! Expected (CLs) 2 2 1
Preliminary CL CL s s limit limit μ <5.3(6.4exp.) # Data 2012 Ldt =20.3fb t ATLAS preliminary t H H (H t t = 7 TeV, s H channelscomb. " "
b !! ! )b Ldt=4.7fb =8TeV s -1 m H -1 m [GeV] H [GeV] umr fES2013 EPS of Summary 71/035 44 / 52 27/11/2013 Single Top Production
• Direct probe of W tb coupling and of
Vtb in CKM matrix. • Challenging, mainly due to the background from W +jets. • Need MVA techniques. • s + t-channel production observed at CDF and D0 in 2009. • t-channel observed both at Tevatron and LHC. • Evidence for s-channel production at D0. • Observation of W t -channel production at CMS. (Evidence by both ATLAS and CMS 2012/2013.)
SARA STRANDBERG , S TOCKHOLM UNIVERSITY P. 10 EPSHEP 2013, S TOCKHOLM , J ULY 22, 2013
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 53 / 44 New 3D Fit by ATLAS
0.045 0.05 ATLAS Preliminary JSF = 0.95 ATLAS Preliminary ATLAS Preliminary 0.03 m = 167.5 GeV bJSF = 0.95 Simulation, = 7 TeVs top 0.04 Simulation, = 7 TeVs Simulation, = 7 TeVs JSF = 1.00 m = 172.5 GeV bJSF = 1.00 0.025 top 0.035 0.04 m = 177.5 GeV JSF = 1.05 top 0.03 bJSF = 1.05 0.02 0.03 0.025 0.015 0.02
normalized events / 0.1 0.02 normalized events / GeV 0.01 normalized events / GeV 0.015 0.01 0.01 0.005 0.005 0 0 0 140 160 180 200 220 60 70 80 90 100 110 0.5 1 1.5 2 2.5 3 mreco [GeV] reco reco top mW [GeV] Rlb
reco reco reco • 3D fit to m , m and R . 600 top W lb ATLAS Preliminary =7 TeV datas btag 500 -1 Best Fit background reco ,1b pT Ldt=4.7 fb W W ∫ Best Fit Rlb = jet1 jet2 Events / GeV 400 m = 172.31 0.75 GeV (pT +pT )/2 top ± stat+JSF+bJSF JSF = 1.014 0.003 b ± stat b bJSF = 1.006 0.008 had lep 300 ± stat reco ,2b pT +pT R = W W lb jet1 jet2 200 pT +pT • In-situ calibration of JES and bJES. 100 0 130 140 150 160 170 180 190 200 210 220 mreco [GeV] • Systematic uncertainties reduced by top 40% w.r.t. previous measurement.
mtop = 172 .31 ± 0.23( stat ) ± 0.27( JSF ) ± 0.67( bJSF ) ± 1.35( syst ) GeV
SARA STRANDBERG , S TOCKHOLM UNIVERSITY P. 16 EPSHEP 2013, S TOCKHOLM , J ULY 22, 2013
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 54 / 44 New Lifetime-Based Measurement by CMS
• Lifetime-based technique, using ≈ · mt . Lxy = γbβBτB 0.4 mB βBτB • First used at CDF. Phys. Rev. D75, 071102 (2007) • Linear mass dependence,
∆Lxy /GeV = 25 − 30 µm • Complementary systematics to traditional measurements, e.g. minimal dependence on jet energy scale. • In each event, select secondary
vertex with largest Lxy . d • Median, Lxy , is used to extract mtop .
mtop = 173 .5 ± 1.5( stat ) ± 1.3( syst ) ± 2.6( pT (t)) GeV
SARA STRANDBERG , S TOCKHOLM UNIVERSITY P. 17 EPSHEP 2013, S TOCKHOLM , J ULY 22, 2013
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 55 / 44 Top Forward-Backward and Charge Asymmetries
• New physics in top sector can alter angular distributions. • Study forward-backward and charge asymmetries.
tt¯ N(∆ y > 0) − N(∆ y < 0) AF B = N(∆ y > 0) + N(∆ y < 0) with ∆y = yt − yt¯
tt¯ N(∆ |y| > 0) − N(∆ |y| < 0) AC = N(∆ |y| > 0) + N(∆ |y| < 0) with ∆|y| = |yt| − | yt¯| C A 0.2 Unfolded ATLAS Preliminary SM Axigluon m=300 GeV = 7 TeVs 0.15 Axigluon m=7000 GeV ∫ L dt = 4.7 fb -1 0.1
0.05
0
-0.05
-0.1 0 100 200 300 400 500 600 700 800 900 m [GeV] tt Phys. Rev. D 87 092002 (2013) Phys. Lett. B 717, 129 (2012) ATLAS-CONF-2013-078 • tt¯ ∼ Tevatron AF B measurements in tension with SM at 2.5σ. • tt¯ LHC AC measurements consistent with SM.
SARA STRANDBERG , S TOCKHOLM UNIVERSITY P. 19 EPSHEP 2013, S TOCKHOLM , J ULY 22, 2013
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 56 / 44 Top Quark Polarization
• Top quarks in tt¯events have negligible polarization in SM. • Can occur in BSM scenarios (e.g. models with large FB asymmetry). • Polar angle of decay product i distributed as: 1 W (cos θi) = 2 (1 + αiP cos θi) P = degree of polarization,
αi = spin-analyzing power. • At tree level, charged leptons and down-type quarks from
W-boson decays have αi = 1 .
• Fit cos θℓ distributions for αlPCPC = −0.035 ± 0.014 ± 0.037 e and µ to extract αℓP . ± +0 .013 αlPCPV = 0 .020 0.016 −0.017
SARA STRANDBERG , S TOCKHOLM UNIVERSITY P. 22 EPSHEP 2013, S TOCKHOLM , J ULY 22, 2013
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 57 / 44 Di-jet energy imbalance
• Parton energy loss manifests itself as a pronounced PRL 105 (2010) 252303 di-jet energy imbalance in central Pb+Pb collisions :
pp Pb Pb p p
PbPb
PbPb But jets are still back-to-back in ϕ: M. Lobodzinska, HI, Fri 12:28 PRC 84 (2011) 024906 P. Kurt, HI, Fri 12:44
gabor.veres@cern.ch EPS HEP 2013, Stockholm, 22 nd July, 2013 9
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 58 / 44 Di-jet energy imbalance
• Parton energy loss manifests itself as a pronounced PRL 105 (2010) 252303 di-jet energy imbalance in central Pb+Pb collisions :
pp Pb Pb p p
PbPb
PbPb But jets are still back-to-back in ϕ: M. Lobodzinska, HI, Fri 12:28 PRC 84 (2011) 024906 P. Kurt, HI, Fri 12:44
[email protected] EPS HEP 2013, Stockholm, 22 nd July, 2013 9
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 59 / 44 Results for new observables N EW LHCb collaboration (1fb -1 ), LHCb-PAPER-2013-037
LHCb LHCb Preliminary Preliminary
LHCb Preliminary Good agreement with SM predictions (from J.Matias et al. arXiv:1303.5794)
")#%!(#!"$* +-0*10**451*#!"$* "#*
J. McCarthy (University of Birmingham) Summary of EPS 2013 27/11/2013 60 / 44