Beauty 2013, Bologna. Measurements of CP violation and mixing in Bs. 0 decays at LHCb. on behalf of the LHCb collaboration

Transcription

1 LPHE Beauty 13, Bologna Meaurement of CP violation and mixing in B decay at Frédéric Dupertui on behalf of the collaboration Laboratoire de Phyique de Haute Energie (LPHE) Ecole Polytechnique Fédérale de Lauanne (EPFL), Switzerland 1 th April 13 F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 1 / 9

2 Outline In thi talk: Analyi of the reonant component in B J/ψπ + π. [Phy. Rev. D86 (1) 56] Meaurement of CP-violation and the B -meon decay width difference with B J/ψK + K and B J/ψπ + π decay. [arxiv:134.6] to be ubmitted to PRD Preciion meaurement of the B B ocillation frequency in the decay B D + π. (preliminary) [LHCB-PAPER-13-6] to be ubmitted to NJP F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 / 9

3 B J/ψπ + π decay: Introduction Phy. Lett. B77 (1) With.41 fb 1, meaured the CP content of the ππ ytem around the f (98) reonance (±9 MeV) in B J/ψπ + π decay. Pure CP-odd final tate! Next tep: Analye the full ππ range. Improve enitivity to CP violation parameter in thi mode. B Combination / 15 MeV } b 3 W - c } c J/ } + π π m(π - π ) (MeV) - F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 3 / 9

4 - B J/ψπ + π decay Phy. Rev. D86 (1) 56 With 1 fb 1, B J/ψπ + π candidate are recontructed in the full ππ ma range. To analye the reonant component, a modified Dalitz plot analyi of the final tate ha been ued: 13 = m (J/ψπ + ) 3 = m (π + π ) Helicity angle θ J/ψ Candidate / 5 MeV ) (GeV ) π m (π m( J/ψπ + π - ) (MeV) 15 5 m (J/ψ π + ) (GeV ) F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 4 / 9

5 Detection efficiency A ample of B J/ψφ obtained from data i ued to reweight the B J/ψπ + π MC ample and obtain the parameter of detection efficiency D function. (GeV ) + - ) m ( Simulation m (J/ + ) (GeV ) Acceptance in θ J/ψ i uniform. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 5 / 9

6 Reonance model ytem i in an iocalar tate at leading order. ππ wavefunction mut be ymmetric. Only pin- and - meon. ρ(77) component added to tet high order procee. B } b W - c } c J/ } + π π - Several cenario have been tried to get the bet ignificant Poion likelihood χ (goodne-of-fit). F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 6 / 9

7 Reult Phy. Rev. D86 (1) 56 The background PDF i parametried from a wrong-ign J/ψπ ± π ± ample and random J/ψ + ρ(77) from MC. The bet ignificant χ i obtained with the f (98)+f (17)+f (137) and non-reonant model. Exitence of B J/ψf (137) clearly etablihed now. Candidate /.6 GeV (a) 15 5 m (J/ψ π + ) (GeV ) Candidate /.5 GeV Pull (b) Pull (a) m (π + π ) (GeV ) m (π + π1 ) (GeV ) co θ J/ψ F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, - 1 th April 13 7 / 9 Candidate /.5 Candidate /.5 GeV (c)

8 Branching fraction ratio and CP content reult Branching fraction ratio with B J/ψφ a normaliation. With B(φ K + K ) = (48.7 ±.5)%, we find: Phy. Rev. D86 (1) 56 B(B J/ψπ+ π ) B(B J/ψφ) Main ytematic are detection efficiencie. = (19.79 ±.47(tat) ±.5(yt))% Larget component come from the f (98) reonance: B(B J/ψf (98))B(f (98) π + π ) B(B J/ψφ) = (13.9 ±.6(tat) (yt))% Except a CP admixture from f (17) with λ = 1 of (. ±.7)% and a ρ(77) component le than 95% CL, we find: CP-odd fraction in B J/ψπ + π i greater than 95% CL. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 8 / 9

9 B J/ψh + h decay with h = K, π phenomenology CP phae φ ariing in the interference between direct decay (φ D ) and decay via mixing (φ M φ D ). In Standard Model: φ = φ,m φ,d = = β + φ penguin β CKMFitter (global SM fit): β = (.36 ±.) rad B b W t, c, u W B B b W + t, c, u t, c, u B How to control penguin pollution: Stephen talk on Tueday. New phyic in box or/and penguin diagram: φ = φ SM + φ NP mall φ SM φ can be enlarged by φ NP. B b t, c, u W + b c c J/ψ B h + h b W u, c, t W + b c c J/ψ h + h F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 9 / 9

10 How to meaure φ with B J/ψh + h decay? In B J/ψh + h decay, the final tate are in CP eigentate f with eigenvalue η f. φ i included in term that look like, for example: Ingredient: η f in(φ ) in( m t) Meauring φ meauring amplitude of the inuoid. m from B D π + decay (in thi talk). Decay in a CP admixture need to be dientangled in CP-even/-odd tate. Angular analyi i required η f = +1, 1. Flavour of the B meon at production (t = ). Flavour tagging algorithm with wrong-tag probability ω. Decay time t. Finite reolution σ t. (1 ω)e 1 m σ t ηf in(φ ) in( m t) F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 1 / 9

11 B J/ψh + h CP content B J/ψK + K around φ(1) reonance: B J/ψφ: P VV decay CP admixture. Angular analyi i required. Three amplitude: A, A (CP-even) and A (CP-odd) y K x µ + φhel θk K + K B µ + µ θµ z K + µ B J/ψK + K non-reonant: S-wave CP-odd. One amplitude: A S B J/ψπ + π i pure CP-odd (> 95% CL) No angular analyi i needed! F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

12 B J/ψh + h differential decay rate B J/ψK + K : Four amplitude + interference term ten term d 4 Γ(B J/ψK + K ) dωdt 1 k=1 Two fold ambiguity in the differential decay rate: h k (t)f k (Ω) (φ, Γ, δ, δ, δ, δ S) (π φ, Γ, δ, δ, π δ, δ S) [rad] 4 arxiv:134.6 Ambiguity reolved by uing the running of phae difference between P-wave and S-wave. (Phyical olution: δ δ ) Γ >. - δ δ S m(k K ) [MeV/c ] B J/ψπ + π : Only h 7(t) term! F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 1 / 9

13 What new in B J/ψh + h analyi? B B J/ψK + K wrt 1 fb 1 preliminary reult of B J/ψφ analyi [LHCB-CONF-1-] Enlarge m KK ma window: m KK m φ(1) < 1 MeV 3 MeV. m KK range divided in 6 bin (gain enitivity to CP parameter). Switch to new fitting procedure ( Fit). Ue the Same Sign Kaon (SSK) tagger in addition to the Oppoite Side (OS) tagger. Enlarge the et of trigger line to be ued. Switch from tranverity angle to helicity angle (better decription of background). J/ψπ + π wrt 1 fb 1 reult of B J/ψπ + π analyi [Phy. Lett. B713 (1) ] Ue the Same Sign Kaon (SSK) tagger in addition to the Oppoite Side (OS) tagger. New decay time acceptance parametried uing B J/ψK in data + correction between B J/ψπ + π and B J/ψK from MC. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

14 B J/ψK + K fit procedure and ignal PDF Fit: A weighted maximum negative log likelihood fit where the weight ( Weight) are coming from the Plot technique when fitting the B ma with two Gauian + exponential background. Only ignal PDF i required! ) Candidate / (.5 MeV/c m(j/ψ K K ) [MeV/c ] Signal PDF for tag deciion q = {+1,, 1} are, for q = +1 for example: +1 = [ ] [ (1 ω) X (t, Ω; Z) + ω X (t, Ω; Z) ] R(t; σ t ) ε t (t) ε Ω (Ω). where X i d4 Γ(B J/ψK + K ) dωdt and X i d4 Γ(B J/ψK + K ) dωdt F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

15 Flavour tagging Oppoite Side (OS) tagger Charge of oppoite ide muon, electron, kaon Charge of oppoite ide vertex Same Side Kaon (SSK) tagger Charge of ame ide kaon Each tagger provide a flavour tag q with a wrong-tag probability etimate η. Candidate/ Candidate/ η OS η SSK F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

16 Flavour tagging performance Eur. Phy. J C7 (1) LHCB-PAPER-13-6 The OS tagger i calibrated uing B ± J/ψK ± decay and SSK tagger uing B D π + decay with linear dependence between true wrong-tag probability ω and etimate η: ω η OS The OS and SSK effective tagging power ɛ tagd : B D π + ɛ tagd OS = (.6 ±.4)% ɛ tagd SSK = (1. ±.3)% B J/ψK + K ɛ tagd OS = (.9 ±.6)% ɛ tagd SSK = (.89 ±.17)% (ee poter by Antonio Falabella: B meon Flavour Tagging at ) LHCB-CONF-1-3 arxiv:134.6 F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

17 Decay time reolution From vertex and track fit, an etimated per-event decay time reolution σ t i obtained. σ t i calibrated by fitting three Gauian to prompt J/ψ + two random kaon event decay time. Only event with t >.3 p are ued in the analyi. Not enitive to reolution detail. A ingle Gauian reolution i ued (with equal dilution). Scale factor: 1.45 ±.6 Single Gauian reolution: 45 f. Candidate / ( f) Candidate / (5 f) σ t [p] Decay time [p] F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

18 B J/ψK + K decay time acceptance The firt decay time biaing cut are coming from the trigger. The trigger decay time acceptance are obtained directly from data. Uing precaled unbiaed event a normaliation, we get: Acceptance 1.8 Acceptance Unbiaed 1 1 Decay time [p]..1 Excluively Biaed 1 1 Decay time [p] Second acceptance at high decay time i due to time-dependent Velo recontruction inefficiencie and ome election cut. Thi acceptance i parametried a (1 + βt) with β = ( 8.3 ± 4.) 1 3 p 1 obtained from a mix of data and MC ample. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

19 B J/ψK + K decay angle acceptance y K x µ + φhel θk K + K B µ + µ θµ z K + µ Uing MC imulation, the decay angle acceptance function: Scaled acceptance integral imulation coθ K Scaled acceptance integral 1.15 imulation coθ µ Scaled acceptance integral imulation - ϕ [rad] h Acceptance vary up to % peak-to-peak. Effect due mainly to: Forward geometry of. Implicit cut on the momentum track to reach the tracking tation downtream the magnet. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

20 B J/ψh + h reult With 1 fb 1, about 7,6 B Candidate / (.74 p) J/ψK + K are recontructed: Candidate / Decay time [p] coθ K Candidate / Candidate / (.67 π rad) arxiv:134.6 The updated analyi of B coθ µ φ J/ψK + K decay give: - ϕ [rad] h =.7 ±.9 (tat) ±.1 (yt) rad, Γ =.663 ±.5 (tat) ±.6 (yt) p 1, Γ =.1 ±.15 (tat) ±.3 (yt) p 1. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 / 9

21 B J/ψh + h reult () Main ytematic on φ, Γ and Γ : arxiv:134.6 Source Γ Γ φ [p 1 ] [p 1 ] [rad] Stat. uncertainty Background ubtraction B J/ψ K background.1.4 Ang. acc. reweighting.7.3 Ang. acc. tatitical..7 Lower decay time acc. model.3. Upper decay time acc. model.4 Length and mom. cale. Fit bia Quadratic um of yt Total uncertaintie The tagging and decay time reolution uncertaintie on the CP parameter are included in the tatitical error. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 1 / 9

22 B J/ψh + h reult (3) Event / 5 MeV With 1 fb 1, about 74 B J/ψπ + π are recontructed: m( J/ψπ - ) (MeV) + π Event / 15 MeV m(π π ) (MeV) Event /. p 5 1 Decay time (p) arxiv:134.6 The updated analyi of B J/ψπ + π decay give: φ = (tat) ±.1 (yt) rad Main ytematic are coming from: Direct CP parameter fixed to 1. Ma ignal-background and decay time background PDF parameter fixed. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 / 9

23 B J/ψh + h reult (4) arxiv:134.6 The combined fit to B J/ψK + K and B J/ψπ + π decay give: φ =.1 ±.7 (tat) ±.1 (yt) rad, Γ =.661 ±.4 (tat) ±.6 (yt) p 1, Γ =.16 ±.11 (tat) ±.7 (yt) p 1. World bet meaurement! New Γ φ / Γ Γ HFAG reult: HFAG fb 1 + CDF 9.6 fb 1 + D 8 fb 1 + ATLAS 4.9 fb 1 D CDF SM 68% CL contour ( ) Combined ATLAS HFAG April 13 [p -1 ] Contour of (logl) =.5 HFAG Spring 13 Meaurement Theory Combined [p-1] F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 3 / 9

24 B J/ψπ + π effective lifetime reult Phy. Rev. D86 (1) 147 arxiv:134.6 Theorically, the B effective lifetime i given by: τ eff = Γ 1 1 y [ 1 + Af y + y 1 + A f ] (1) y where y = Γ Γ. (ee previou talk by Robert Knegjen). B J/ψπ + π : 1 < A B J/ψπ+ π (φ ) < 1. In the limit φ A B J/ψπ+ π = +1. τ B J/ψπ+ π φ eff Γ 1,H Experimentally, τ eff i obtained from a ingle exponential e t/τ eff likelihood fit to the decay time pectrum. B J/ψπ + π effective lifetime meaurement: τ eff B J/ψπ+ π = 1.65 ±.4 (tat) ±.4 (yt) p, Γ eff B J/ψπ+ π =.65 ±.9 (tat) ±.9 (yt) p 1 φ Γ,H. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 4 / 9

25 arxiv: φ propect φ from B J/ψφ and B J/ψπ + π decay: arxiv: σφ tat Upgrade Theory (1 fb 1 ) 18 (5 fb 1 ) uncertainty B J/ψφ B J/ψπ+ π For more detail on the upgrade Maurizio talk, next eion. φ reult from B J/ψη, B J/ψη and B D + D decay 451 ± 3 B D + D (1 fb 1 ) φ may tart with. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 5 / 9

26 m meaurement with B D π + decay m i the ocillation frequency of the B B mixing: b t, c, u b W + B W W B B t, c, u t, c, u B t, c, u b W b Senitivity: σ( m ) ɛ(1 ω) e 1 m σ t = ɛd e 1 m σ t Important to have an excellent decay time reolution σ t and great tagging performance (bet ɛd ). Ingredient: Flavour tag at production uing OS and SSK tagging algorithm. Decay time with per-event reolution σ t and cale factor S σt. Same ingredient than B J/ψh + h analyi. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 6 / 9

27 B D π + decay (preliminary) LHCB-PAPER-13-6 B D π + decay are recontructed in five D decay channel: candidate / (15 MeV/c ) 4 a) D φπ data fit B D π + + B D K miid bkg. comb bkg (D π + ) invariant ma [MeV/c ] candidate / (15 MeV/c ) b) D K*K data fit B D π + + B D K miid. bkg. comb. bkg (D π + ) invariant 545 ma 55 [MeV/c 555 ] candidate / (15 MeV/c ) 1 c) + D K K π data fit B D π + + B D K miid. bkg. comb. bkg. candidate / (15 MeV/c ) 5 d) D K π + π data fit B D π + + B D K miid. bkg. comb. bkg. candidate / (15 MeV/c ) 1 e) D π + π π data fit B D π + + B D K comb. bkg (D π + ) invariant ma [MeV/c ] (D π + ) invariant ma [MeV/c ] (D π + ) invariant ma [MeV/c ] With 1 fb 1 34, B D π + candidate. Γ from latet B J/ψh + h analyi and Γ from PDG. σ t i calibrated by fitting a ingle Gauian to prompt D + random π + event decay time. Scale factor: 1.5 < S σt < 1.45 Average reolution: 44 f. Decay time acceptance E t(t) parametried from MC and free in the fit. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 7 / 9

28 m preliminary reult LHCB-PAPER-13-6 candidate / (.1 p) 4 Tagged mixed Tagged unmixed Fit mixed Fit unmixed decay time [p] m = ( ±.3(tat) ±.6(yt)) p 1 World bet meaurement of m! Main ytematic coming from the z- and momentum cale. F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 8 / 9

29 Concluion Phy. Rev. D86 (1) 56 LHCB-PAPER-13-6 Analyi of the reonant component in B J/ψπ + π. B(B J/ψπ+ π ) B(B J/ψφ) CP-odd fraction in B = (19.79 ±.47(tat) ±.5(yt))% J/ψπ + π i greater than 95% CL. Meaurement of CP-violation and the B -meon decay width difference with B J/ψK + K and B J/ψπ + π decay. φ =.1 ±.7 (tat) ±.1 (yt) rad, Γ =.661 ±.4 (tat) ±.6 (yt) p 1, Γ =.16 ±.11 (tat) ±.7 (yt) p 1. Preciion meaurement of the B B ocillation frequency in the decay D + π (preliminary). B m = ( ±.3(tat) ±.6(yt)) p 1 Reult with 1 fb 1 here, we have 3 fb 1 in total on tape! Stay tuned! Thank you for your attention! F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 9 / 9 arxiv:134.6

30 Backup Slide F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 3 / 9

31 detector F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

32 Detection efficiency and background compoition The background PDF i parametried from a wrong-ign J/ψπ ± π ± ample and a MC ample of random J/ψ + ρ (77). Candidate /.6 GeV (a) Candidate /.1 GeV (b) Candidate / m (J/ψ ψ π + ) (GeV ) m ( π + π - ) (GeV ) co θ J/ψ F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April 13 3 / 9

33 φ tatu before Moriond 13 Tagged angular time-dependent analyi of B (1 fb 1, prel.) J/ψφ φ J/ψφ =.1 ±.11 (tat) ±.7 (yt) rad Tagged time-dependent analyi of B J/ψπ + π (1 fb 1 ) φ J/ψππ = (tat) (yt) rad Combination of B J/ψφ and B J/ψπ + π reult: fb 1 + CDF 9.6 fb 1 + ATLAS 4.9 fb 1 D HFAG Fall 1 68% CL contour ( ) φ J/ψφ+J/ψππ =. ±.83 (tat) ±.7 (yt) rad.1.5 CDF SM Combined ATLAS F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

34 B J/ψK + K differential decay rate d 4 Γ(B J/ψK + K ) dωdt 1 k=1 h k (t)f k (Ω) C 1 λ λ in φ λ co φ, S, D. 1 + λ 1 + λ 1 + λ F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9

35 m meaurement with B D π + decay P ig The ignal decay time PDF look like: t (t, q σ t, η) {Γ e Γ t 1 Γ [coh( t) + q[1 ω(η)] co( mt)]θ(t)} G(t, S σt, σ t)e t(t)ɛ F. Dupertui (LPHE-EPFL-CH) φ, Γ, Γ, 1 th April / 9