Measurements of the CKM angle g at BaBar Fernando Martínez-Vidal, On behalf of the BaBar Collaboration CKM angle g • Apex of the CKM Unitary Triangle (UT) over constrained CP violation measurements give angles Semileptonic decay rates (and other methods) give sides • Precise measurement of SM parameters • Search for NP in discrepancies of redundant measurements • Still have some work to do on g: less precisely known UT angle (most difficult to measure) See also UTfit analysis at http://www.utfit.org/ Very impressive consistency ICHEP 2010, Paris Fernando Martinez Vidal 1 CKM angle g • Apex of the CKM Unitary Triangle (UT) over constrained CP violation measurements give angles Semileptonic decay rates (and other methods) give sides • Precise measurement of SM parameters • Search for NP in discrepancies of redundant measurements • Still have some work to do on g: less precisely known UT angle (most difficult to measure) This talk Experiments providing most of analyses today • Important to measure g since, together with |Vub|, selects r-h value independently of most types of NP SM candle type of measurement 3.1 GeV e+ 9 GeV e– 468M BB pairs ICHEP 2010, Paris 3.5 GeV e+ 8 GeV e– 657M BB pairs ~10-15o • The constraint on g come from tree-level B→DK decays Fernando Martinez Vidal 1 γ from B→DK decays B * Measure interference between tree amplitudes b→u and b→c • Use final state accessible from both D and D • Largely unaffected by New Physics • Clear theoretical interpretation of observables in terms of γ • Difficult because BFs are small due to CKM suppresion (10 0 * 0 -5- 10-7, so not many events) and rB=|Aub|/|Acb| is small due to further CKM and color suppressions (small interference) B All measurements are statistics limited ICHEP 2010, Paris Fernando Martinez Vidal 2 γ from B→DK decays Neutral B→D(*)0K*0 rB~0.3 Charged B→D(*)0K(*) rB~0.1 B GLW CP-odd CP-even f= * f= K- K+ π+ π- K0s π0 K0s ω ADS K+ πK+ π-π0 K+ π- π+ π- Dalitz plot π0 π+ Dalitz plot K0s π+ π- π- K0s π+ π- ADS K0s K+ K- K+π-π0 K+πK+π-π+ π- CP-conj CP-conj K0s Φ CP-conj CP-conj • Complementary methods applied on same B decay * modes share the same hadronic parameters (rB, dB) and g • Strategy: many decay chains are analyzed and then B combined to improve the overall sensitivity to γ • In this talk Atwood, Dunietz, Soni, PRL 78, 3357 (1997) Gronau, London, Wyler, PLB 253, 483 (1991); PLB 265, 172 (1991) ICHEP 2010, Paris we present new or recent results 3 γ from B→DK decays Decay amplitude s D K S 0 0 D K S s A( B [ K S ]K ) D0 decay strong phase variation Hadronic parameters rB e b→c rB=|A(b→u)|/|A(b→c)| dB (strong phase difference between A(b→u) and A(b→c)) Dalitz plot method 2 s m ( K ) S No D-mixing nor CPV ig id B s s b→u Hadronic parameters 0 s D K S A( B [ K S ]K ) s D 0 K S determined experimentally from data Giri, Grossman, Soffer, Zupan, PRD 68, 054018 (2003); Bondar, unpublished. ICHEP 2010, Paris rB e ig id B s b→c Fernando Martinez Vidal b→u s 4 γ from B→DK decays Decay amplitude No D-mixing nor CPV D K S 0 y rB sin( d B g ) 0 A( B [ K S ]K ) Interference terms in decay rates proportional to D K S rB e b→c x rB cos(d B g ) Dalitz plot method ig id B Relative weak phase g changes sign 0 b→u D 0 K S D K S Fit for x± and y± for each B decay mode A( B [ K S ]K ) rB e ig id B b→c ICHEP 2010, Paris Fernando Martinez Vidal b→u 5 γ from B→DK decays D K S Large interference in some regions of the Dalitz plot, e.g. D0→KSr D0→K*-+ vs D0→K*+- A( B [ K S ]K ) 0 D K S rB e b→c b→u D K S D 0 K S 0 CF K*(892)+π- rB e ig id B b→c ICHEP 2010, Paris ig id B CF K*(892)+π- A( B [ K S ]K ) No D-mixing nor CPV DCS K*(892)+π- Decay amplitude 0 Dalitz plot method Fernando Martinez Vidal DCS K*(892)+π- b→u 6 Experimental techniques • Exclusive reconstruction of multiple B decays: B±→DK±, B±→D* [D0]K± , B±→D* [Dg]K±, B±→DK*± • Exploit kinematic constraints from beam energies. mES=√E*2beam -|pB*|2 ΔE=EB*-E*beam • The main source of background : e e + - with q=u,d,s,c → qq, ΔE • Event shape variables combined into a linear signal region (Fisher) or non linear (Neural Network) combination. Tagging information sometimes used sidebands BB Dπ spherical e+ qq e- e+ jet-like e- mES • Signal is separated from background through unbinned maximum likelihood fits to B ± data using mES, DE and Fisher (or Neural Network) discriminant • Use large B ± → D(*) K(*)± → D(*) ± data control samples (rB~0.01, x10 smaller than for DK) ICHEP 2010, Paris Fernando Martinez Vidal 7 γ from D Dalitz plot method • BaBar analysis based on complete data sample (468 M BB pairs) • Reconstruct B →DK , B →D [D ]K arXiv:1005.1096. Sub. to Phys. Rev. Lett. , B±→D* [Dg]K±, and B±→DK*± final states with D→KSπ+π-, KSK+K- (eight different final states for each B charge) ± ± ± Only BaBar * 0 ± B±→DK± All components Continuum + BB BG Continuum + BB + D BG • Efficiencies improved substantially (20% to 40% relative) with respect to previous BaBar measurement (383 M BB) PRD78, 034023 (2008) • Reprocessed data set with improved track reconstruction • Improved particle identification • Revised K selection criteria: negligible background from D→ h h and B→Da (1260) + - + - S ICHEP 2010, Paris Fernando Martinez Vidal 1 8 D→KS+-,KSK+K- amplitude analysis arXiv:1004.5053. Accepted by Phys. Rev. Lett. • Extract D amplitude from an independent analysis of flavor tagged D mesons (D →D π ) • Experimental analysis using complete data sample benefits from synergy with D-mixing analysis 0 0 Model determined without (reference) and with D-mixing *+ 0 + See Matt Bellis talk in this session for more details • Fit for amplitudes relative to CP eigenstates [K r(770) and K a (980)] and assume no direct CPV S Wave ππ S-wave Parameterization K-matrix Main differences with Belle Kπ S-wave ππ P-wave K-matrix (LASS-like) S 0 Wave K±Ks S-wave K+K- S-wave BW: ω(782), G.S ρ(770) BW: CA and DCS K*(892), K+K- D-wave CA K*(1680) ππ D-wave Kπ D-wave ICHEP 2010, Paris BW: CA and DCS a0(980), CA a0(1450) K+K- P-wave Kπ P-wave Parameterization Flatte a0 (980), BW a0(1450) and f0(1370) BW Φ(1020) BW f2(1270)0 BW f2(1270)0 BW CA and DCS K2*(1430) Good fit quality (c2/ndof) taking into account statistical, experimental and model uncertainties Fernando Martinez Vidal 9 γ from D Dalitz plot method • CP violation parameters are extracted from simultaneous unbinned maximum likelihood fit to B ± → D(*) K(*)± data using mES, DE, Fisher and the Dalitz plot distributions (s+,s-) B-→DK- x rB cos(d B g ) y rB sin( d B g ) g arXiv:1005.1096. Sub. to Phys. Rev. Lett. B-→D*K- g dB B+→DK+ B+→DK+ B-→DK- Differences between B+ and B- gives information on g ICHEP 2010, Paris B+→D*K+ Fernando Martinez Vidal B-→DK*B+→DK*+ 10 γ from D Dalitz plot method • Use frequentist method to obtain the (common) weak phase g and the hadronic parameters r , B dB (different for each B decay channel) from 12 (x,y) observables arXiv:1005.1096. Sub. to Phys. Rev. Lett. rB ( DK ) 0.096 0.029 042 rB* ( D* K ) 0.13300..039 066 crS ( DK * ) 0.14900..062 d B ( DK ) (119 19 20 ) d B* ( D* K ) (82 21) d S ( DK * ) (111 32) g (mod 180) ( 68 14 4 3 ) stat syst model Our previous result: g (mod 180) ( 76 22 5 5 ) 3.5s significance of CPV [Error on g scales roughly as 1/rB] • Smaller stat error due to additional data + improved reconstruction + slightly higher r (DK) • Model error benefited from overlap with D-mixing analysis (e.g. reduction of experimental B uncertainties inherent to the model uncertainty) 10.8 g (mod 180) ( 78.4 11 .6 3.6 8.9 ) ICHEP 2010, Paris rB ( DK ) 0.16000..040 038 Fernando Martinez Vidal 11 γ from ADS method arXiv:1006.4241. Sub. to Phys. Rev. D • Update with final data sample (468 M BB pairs). Previous analysis used 232 M BB pairs • Reconstruct B →DK , B →D [D ]K ± ± ± * 0 ± , and B±→D* [Dg]K±, with +± D→K π (“same sign”) + D→K-± (“opposite sign”) • • CP asymmetry since “equalizes” the magnitudes of the interfering amplitudes “opposite sign” PRD72, 032004 (2005) “Maximizes” B±→DK± First sign of an ADS signal in B± → DK± (2.1s) and B± → D* K± (2.2s) ICHEP 2010, Paris 2.1s Fernando Martinez Vidal 12 γ from ADS method • Fit directly observables R ± ADS and B “same sign” yields reconstruct the ADS asymmetry RADS AADS ( B [ K ]D K ) Good sensitivity to rB 1 ( R R ) rB2 rD2 2rB rD cos(d B d D ) cos g 2 R R 2rB rD sin( d B d D ) sin g / RADS R R B+→DK+ R ( B [ K ] K ) D R ( B [ K ] D K ) AADS ( DK ) 0.86 0.47 00..12 16 ([ D ]K ) 0.018 0.009 0.004 0 * RADS ([ Dg ]K ) 0.013 0.014 0.008 ICHEP 2010, Paris to B-→DK- RADS ( DK ) 0.011 0.006 0.002 * ADS arXiv:1006.4241. Sub. to Phys. Rev. D * AADS ([ D 0 ]K ) 0.77 0.35 0.12 * 25 AADS ([ Dg ]K ) 0.36 0.94 00..41 Fernando Martinez Vidal 13 γ from ADS method arXiv:1006.4241. Sub. to Phys. Rev. D • Use frequentist interpretation (similar to Dalitz plot method) to obtain weak phase g and hadronic parameters rB, dB from RADS(*) and AADS(*) observables Inputs: rD = δD = arg [ |A(D0→ K-π+)| (HFAG) K-π+)| |A(D0→ A(D0→ K-π+) A(D0→ K-π+) rD = (5.78 ± 0.08)% ] (CLEOc) δD = (201.9 +11.4 -12.4 )ᵒ (HFAG, CLEOc) rB ( DK ) 0.09500..051 041 035 rB* ( D* K ) 0.09600..051 [54o ,83o ] [0.067,0.125] [0.094,0.175] BaBar Dalitz plot method ICHEP 2010, Paris Fernando Martinez Vidal 14 γ from GLW method arXiv:1007.0504. Sub. to Phys. Rev. D • Update with final data sample (468 M BB pairs). Previous analysis used 383 M BB pairs PRD77, 111102 (2008) • Reconstruct B →DK final states with D→K+K-,π+π- (CP even) and D→KS0,KSw,KSf (CP odd) (five different final states for each B charge) ± ± B-→DK- All components Continuum + BB BG Continuum + BB + D BG • Efficiencies improved substantially (40% to 60% relative) with respect to previous measurement • Reprocessed data set with improved track reconstruction • Improved particle identification • Introduce Fisher discriminant in the fit rather than apply cut on event shape variables ICHEP 2010, Paris Fernando Martinez Vidal 15 γ from GLW method • Extract signal yields fitting directly to observables R RK / ( B DCP K ) ( B DCP K ) ( B DCP ) ( B DCP ) ACP ± K/ arXiv:1007.0504. Sub. to Phys. Rev. D , RK/, and ACP± RK / 0 ( B D K ) ( B D K ) 0 ( B D ) ( B D ) 0 ( B DCP K ) ( B DCP K ) ( B DCP K ) ( B DCP K ) 0 RCP RK / RK / 3.6s significance of CPV in B±→DK± from ACP+ ACP 0.25 0.06 0.02 ACP 0.09 0.07 0.02 RCP 1.18 0.09 0.05 RCP 1.07 0.08 0.04 ICHEP 2010, Paris Fernando Martinez Vidal 16 γ from GLW method • Extract signal yields fitting directly to observables R RK / ( B DCP K ) ( B DCP K ) ( B DCP ) ( B DCP ) ACP ± K/ arXiv:1007.0504. Sub. to Phys. Rev. D , RK/, and ACP± RK / 0 ( B D K ) ( B D K ) 0 ( B D ) ( B D ) 0 ( B DCP K ) ( B DCP K ) ( B DCP K ) ( B DCP K ) 0 RCP RK / RK / 3.6s significance of CPV in B±→DK± from ACP+ ACP 0.25 0.06 0.02 x 0.057 0.039 0.015 ACP 0.09 0.07 0.02 RCP 1.18 0.09 0.05 RCP 1.07 0.08 0.04 1 x RCP (1 ACP ) RCP (1 ACP ) 4 x 0.132 0.042 0.018 Consistent with and of similar precision to Dalitz results x 0.103 0.037 0.006 0.007 x 0.060 0.039 0.007 0.006 [Dalitz results] ICHEP 2010, Paris Fernando Martinez Vidal 16 γ from GLW method • Extract signal yields fitting directly to observables R RK / ( B DCP K ) ( B DCP K ) ( B DCP ) ( B DCP ) ACP ± K/ arXiv:1007.0504. Sub. to Phys. Rev. D , RK/, and ACP± RK / 0 ( B D ) ( B D ) 0 RCP 3.6s significance of CPV in B±→DK± from ACP+ 0 ( B D K ) ( B D K ) ( B DCP K ) ( B DCP K ) ( B DCP K ) ( B DCP K ) 0 RK / RK / Dalitz ACP 0.25 0.06 0.02 ACP 0.09 0.07 0.02 RCP 1.18 0.09 0.05 RCP 1.07 0.08 0.04 ICHEP 2010, Paris 1 x RCP (1 ACP ) RCP (1 ACP ) 4 x x (Dalitz) 0.163 0.055 (3.0s ) x x (GLW) 0.189 0.062 (3.1s ) Fernando Martinez Vidal 16 γ from GLW method • Extract signal yields fitting directly to observables R RK / ( B DCP K ) ( B DCP K ) ( B DCP ) ( B DCP ) ACP ± K/ arXiv:1007.0504. Sub. to Phys. Rev. D , RK/, and ACP± RK / 0 ( B D ) ( B D ) 0 RCP 3.6s significance of CPV in B±→DK± from ACP+ 0 ( B D K ) ( B D K ) ( B DCP K ) ( B DCP K ) ( B DCP K ) ( B DCP K ) 0 RK / RK / Dalitz+GLW ACP 0.25 0.06 0.02 ACP 0.09 0.07 0.02 RCP 1.18 0.09 0.05 RCP 1.07 0.08 0.04 1 x RCP (1 ACP ) RCP (1 ACP ) 4 4.4s significance of CPV in B±→DK± ICHEP 2010, Paris x x (Dalitz GLW) 0.175 0.040 Fernando Martinez Vidal 16 γ from GLW method arXiv:1007.0504. Sub. to Phys. Rev. D • Use frequentist interpretation (similar to Dalitz plot method) to obtain weak phase g and hadronic parameters rB, dB from RCP± and ACP± observables RCP 1 rB2 2rB cos d B cos g Weak sensitivity to rB ACP 2rB sin d B sin g 1 rB2 2rB cos d B cos g [54o ,83o ] [0.067,0.125] BaBar Dalitz plot method ICHEP 2010, Paris Fernando Martinez Vidal 176 Summary and outlook • Recent progress on g, the hardest UT angle to measure • BaBar Dalitz plot method approach drives the measurement and benefited from synergy with Dmixing analysis (e.g. reduction of experimental uncertainties inherent to the model uncertainty) (see Matt Bellis talk later in this session) • First sign of an ADS signal in B ± → DK± and B± → D* K± • Compelling evidence of direct CPV in B± → D(*)K(*)± decays g (mod 180) ( 68 14 4 3 ) stat syst model 3.5s significance of CPV, B± → D(*)K(*)± combined, Dalitz only 3.6s significance of CPV, B± → DK± only, GLW only ICHEP 2010, Paris Fernando Martinez Vidal 18 Summary and outlook • Recent progress on g, the hardest UT angle to measure • BaBar Dalitz plot method approach drives the measurement and benefited from synergy with Dmixing analysis (e.g. reduction of experimental uncertainties inherent to the model uncertainty) (see Matt Bellis talk later in this session) • First sign of an ADS signal in B ± → DK± and B± → D* K± • Compelling evidence of direct CPV in B± → D(*)K(*)± decays x x (Dalitz GLW) 0.175 0.040 4.4s significance of CPV in B±→DK± only, Dalitz+GLW combined ICHEP 2010, Paris Fernando Martinez Vidal 18 Summary and outlook Experiments providing most of analyses today • Recent progress on g, the hardest UT angle to measure • BaBar Dalitz plot method approach drives the 3.1 GeV e+ 9 GeV e– 468M BB pairs measurement and benefited from synergy with Dmixing analysis (e.g. reduction of experimental uncertainties inherent to the model uncertainty) 3.5 GeV e+ 8 GeV e– (see Matt Bellis talk later in this session) o 657M BB pairs ~10-15 • First sign of an ADS signal in B ± → DK± and B± → D* K± Experiments that can also give results in near future • Compelling evidence of direct CPV in B± → D(*)K(*)± decays • Close to “last word” from BaBar (~10-15 error) • Still statistics limited, even with full data sets • BaBar “legacy” g average from GLW, ADS o ~2-3o Planned facilities and Dalitz plot methods in progress <1o ICHEP 2010, Paris • Need to reduce the error in order to see possible deviations Fernando Martinez Vidal 18 Backup BaBar detector and data sample Delivered luminosity Recorded luminosity Instrumented Flux return (Muon and hadron reco.) Recorded Υ(4S): 432 fb-1 Recorded Υ(3S): 30.2 fb-1 Recorded Υ(2S): 14.5 fb-1 3.1GeV e+ Off peak Magnet (1.5 T) Υ(3S) Υ(2S) e9GeV Υ(4S) Detector of Internally Reflected Cherenkov (PID, Kaon separation from pions) Drift Chamber (Main tracking system) Silicon Vertex Tracker (Tracking at low momentum and vertex reconstruction) Electromagnetic Calorimeter (Detection of neutral particles) • BaBar data taking ended on 7th April 2008 • BaBar recorded 470M BB at Υ(4S) γ from D Dalitz plot method • Signal yields as used in the final fit for CP parameters arXiv:1005.1096. Sub. to Phys. Rev. Lett. PRD81, 112002 (2010) B decay mode BaBar (KS+-) 468 M BB BaBar (KSK+K-) 468 M BB Belle (KS+-) 657 M BB B±→DK± 896±35 154±14 757±30 B±→D*(D0)K± 255±21 56±11 168±15 B±→D*(Dg)K± 193±19 30±7 83±10 B±→DK*± 163±18 28±6 (not updated to 657 M BB) • Efficiencies improved substantially (20% to 40% relative) with respect to previous BaBar measurement (383 M BB) PRD78, 034023 (2008) • Reprocessed data set with improved track reconstruction • Improved particle identification • Revised K selection criteria: negligible background from D→ h h and B→Da (1260) S + - + - 1 D→KS+-,KSK+K- amplitude analysis arXiv:1004.5053. Accepted by Phys. Rev. Lett. • Extract D amplitude from an independent analysis of flavor tagged D mesons (D →D π ) • Experimental analysis using complete data sample benefits from synergy with D-mixing analysis 0 0 *+ 0 Model determined without (reference) and with D-mixing + • Fit for amplitudes relative to CP eigenstates [K r(770) and K a (980)] and assume no direct CPV S 540 800±800 S 0 79 900±300 See Matt Bellis talk in this session for more details γ from D Dalitz plot method • CP violation parameters are extracted from simultaneous unbinned maximum likelihood fit to B ± → D(*) K(*)± data using mES, DE, Fisher and the Dalitz plot distributions (s+,s-) arXiv:1005.1096. Sub. to Phys. Rev. Lett. B-→DK- B+→DK+ Most precise measurement of (x,y) Consistent results with latest Belle results PRD81, 112002 (2010) ICHEP 2010, Paris γ from D Dalitz plot method arXiv:1005.1096. Sub. to Phys. Rev. Lett. γ from D Dalitz plot method arXiv:1005.1096. Sub. to Phys. Rev. Lett. Other hadronic parameters relevant for g • Updated search for B →D K and B+→D K • Can only proceed through annihilation or rescattering + + 0 + *0 •Allows an estimation of r for B from r for B needed for • B →D K measures r sin(2b+g) in time-dependent asymmetry • B →D K measures g in direct CPV (similar to B ) • BaBar analysis with full data sample: 468 M BB arXiv:1005.0068. Submitted to PRD • No evidence for signals 0 B 0 0 0 0 0 *0 0 B + 0 B + BaBar vs WA 24 -16 ( 73 ) Courtesy of V. Tisserand and the CKM fitter group 21 ( 71-25 ) Backup CKM angle g • ui u, c, t The electroweak coupling strength of W± to quarks described by the CKM matrix d s 2 u 1 2 2 c Vij 1 2 3 2 A ( 1 r i h ) A t d j d , s, b b A ( r ih ) 2 4 A O ( ) 1 3 Wolfenstein parameterization ~0.22 A~0.8 r~0.16 h~0.34 Unitarity condition from 1st and 3rd columns Overconstraint apex coordinates • CP violation measurements give angles • Semileptonic decay rates (and other methods) give sides • Precise measurement of SM parameters • Search for NP in discrepancies of redundant measurements CKM angle g γ from B→DK decays Decay amplitude No D-mixing nor CPV D K S 0 CP-even CP-odd 0 A( B [ K S ]K ) π+ π K- K + K0sπ0 K0sω K0sΦ K0sρ GLW-like method D K S rB e ig id B b→c b→u D K S D 0 K S GLW 0 A( B [ K S ]K ) Large interferences in some Dalitz plot regions Strong phases varying over the Dalitz plane Gronau, London, Wyler, PLB 253, 483 (1991); PLB 265, 172 (1991) rB e ig id B b→c b→u γ from B→DK decays K+π- D K S rB e ig id B b→c b→u D K S D 0 K S A( B [ K S ]K ) CF Large interferences in some Dalitz plot regions Strong phases varying over the Dalitz plane Atwood, Dunietz, Soni, PRL 78, 3357 (1997) 0 CF K*(892)+π- D K S A( B [ K S ]K ) K+π-π0 ADS K+π-π+π- No D-mixing nor CPV DCS K*(892)+π- Decay amplitude 0 ADS-like method 0 K*(892)+π- b→c rB e ig id B DCS K*(892)+π- b→u