CP Violation in the B system

Transcription

1 CP Violation in the B system Outline: Mixing induced CPV and B s mixing phase s Search for CPV in B s mixing Direct CPV in B DK and CKM phase Direct CPV in charmless B decays new Ulrich Uwer Heidelberg University On behalf of the LHCb Collaboration La Thuile 2013

2 Mixing induced CP Violation and s B s D f CP B s J/ (KK) B s J/ A mix A mix e i M M B s D Interference of mixing & decay: CPV phase Standard Model: NP? + small penguin pollution Precise prediction: SM s rad (CKMFitter) Possible New Physics contribution: 2

3 new B s J/ ( ) (KK) LHCb-Paper to be submitted to PRD experimentally clean VV final state: angular analysis to separate CP even/odd components Use helicity frame to describe decay angles (cos K, cos,, h ) Non-resonant KK (s-wave) comp.: CP odd 1 fb -1 Preliminary signal evts Helicity angles 3

4 Analysis procedure Unbinned maximum likelihood fit to proper time and angular distributions: Acceptance correction: Proper time acceptance from data Angular acceptance from simulation 1 fb -1 Preliminary Proper time resolution: Calibration of per-event error w/ prompt J/ s + random tracks t 45 fs 4

5 Flavor Tagging LHCb-Paper new Same Side Kaon Tagger Calibrated using B s D s Diff. calibration for B s / B s = 10.26%, =35.27% D 2 = ( )% Opposite Side Tagger (OST) Calibrated using B J/ K + Different calibration for B/B = 33.00%, =36.83% D 2 = ( )% Combined tagging performance = 39.36%, =35.9% D 2 = ( )% 5

6 Fitting procedure LHCb-Paper sfit approach to fit only signal events Fit in 6 bin of KK-mass: different s-wave component and p and s wave phase difference Preliminary 1 fb -1 Account for KK-mass dependence of the p+s wave interference terms: KK-mass dependent corrections C SP Allow for CPV in decay by fitting for: 1 CPV in decay CP q p A A f f 6

7 new Sign of LHCb-Paper Invariance: (, s,,,, ) s s 0 (, s,,,, ) s s 0 Resolved via m KK dependent phase difference between p and s-wave (resonant p-wave contribution changes phase from - /2 + /2) 1 fb -1 Preliminary Physical solution s > 0 7

8 Results LHCb-Paper Preliminary Preliminary CP-even CP-odd S-wave Preliminary Preliminary 8

9 new Mixing Phase s LHCb-Paper fb -1 Preliminary (stat. error only) Preliminary = (compatible w/ no CPV in decay) Systematics - s : Angular accept. ; : Bckg + t accept. 9

10 B s J/ B s J/ is (pure) CP odd state no angular analysis Phys.Lett. B713 (2012) Repeat analysis of PL B713 but using OST and SSKT information. (~7420 signal events) Constrain and to the J/ result: 1 fb -1 CP odd (>97.7%) new Preliminary LHCb-Paper f 0 Simultaneous fit of B s J/ and B s J/ new Preliminary LHCb-Paper

11 CP Violation in B s Mixing LHCb-CONF B 0 B 0 B 0 B 0 X CP + X a ( B X ) ( B 0 0 q q q sl 0 0 ( Bq X ) ( Bq X ) X ) Problem: Production asymmetry at LHC Use quickly oscillating B s mesons only Preliminary Main syst.: L0 -trigger efficiency Consistent with Standard Model (A.Lenz) 11

12 CKM Angle 12

13 Determination of from B DK decays V cb D 0 K i r D e D V ub B i( r B B e ) f D K D 0 K Gronau, London, Wyler (GLW) Atwood, Dunietz, Soni (ADS) f D = KK, (CP state) f D = K and K B D(KK) K B D( ) K LHCb B D(KK) B D( ) Phys. Lett. B 712 (2012) 203. LHCb B D( + K - ) K B D(K + - ) K B D( + K - ) B D(K + - ) Phys. Lett. B 712 (2012) 203. Giri, Grossman, Soffer, Zupan (GGSZ) Self conjugated Dalitz modes 13

14 ADS with B D(K3 )K LHCB-CONF ADS with K3 mode * ) B D ( + K ) K B D ( + K ) B D(K ) K B D(K ) favored B DK part. reco. First observation [5.7 of both modes Observables: e.g. D K R A DK ADS DK ADS ([ K ([ K ([ K ([ K ] ] ] ] D D D D K K K K ) ) ) ) ([ K ([ K ([ K ([ K ] ] ] ] D D D D K K K K ) ) ) ) r 2 B 2r B r D r 2 D sin 2r B r sin( D cos B cos( D ) / B R DK ADS D ) *) A. Powell, CERN-THESIS

15 GGSZ analysis: B D(K s h + h - )K x y r r B B cos( sin( B B ) ) D K S 690 signal events Giri, Grossman, Soffer, Zupan PLB 718(2012) 43 m ± = m(k S h ± ) B + B - D K S K + K signal events 2 r B r B (0,0) = ( ) ⁰ r B = 0.07 ± 0.04 N( B ) i K i ( x 2 y 2 ) K i 2 K K i i { x c i y s } i 15

16 GGSZ analysis: B D(K s hh)k x y r r B B cos( sin( B B ) ) D K S 690 signal events Giri, Grossman, Soffer, Zupan PLB 718(2012) 43 m ± = m(k S h ± ) B + B - CLEO binning D K S K + K signal events 2 r B r B (0,0) = ( ) ⁰ r B = 0.07 ± 0.04 N( B ) i K i ( x 2 y 2 ) K i 2 K K i i { x c i y s } i c i, s i from CLEO 16

17 Combination of B DK results LHCB-CONF fb -1 For comparision: BaBar : ( ) Belle : ( ) 17

18 Direct CPV in charmless decays Tree + Penguin s V ub s s s direct CPV First evidence for CPV in B s : 3.3 *) B s - K + B s + K - *) Corrected for production and detection asym. PRL 108, (2012) 18

19 Evidence for CPV in B h h + h - (h=k, ) LHCB-CONF fb -1 B - K - K + K - B + K + K + K - LHCB-CONF LHCB-CONF Use A CP (B J/ K ) to estimate production and detection asymmetry. 19

20 Phase space dependence B + - B K + K - LHCB-CONF Bkg J/ 0, f 0 f 2 (1270) K* K* 0 large pos. CPV outside resonances (>9 ) large negative CPV (>7 ) 20

21 Conclusion New LHCb measurement of B s mixing phase s and s = rad s = ps -1 Test of CPV in B s mixing agrees with Standard Model s First combined LHCb determination of angle Evidence of CPV in charmless 3-body B-decays All measurements use only 1 fb -1 of data (2011), Additional 2 fb -1 from 2012 is being analyzed now. 21

22 Backup 22

23 B s J/ ( ) (KK) Results 23

24 Correlations 24

25 B s J/ Systematic Uncertainties 25

26 Combined B s J/ and J/ Only B s J/ (corresponds to H in the limit of s = 0) 26

27 Penguin pollutions in B s J/ O. Leroy, La Thuile

28 CKM Angle 28

29 GLW and ADS measurements Phys. Lett. B712 (2012) 203. GLW D 0 decays to CP state: B D(KK) K B D(KK) B D( ) K B D( ) ADS D 0 decays suppressed: B D( + K - ) K B D( + K - ) B D(K + - ) K B D(K + - ) favored First observation of OS decay 29

30 ADS with B D(K3 )K 30

31 Combination of B DK results LHCB-CONF fb -1 For comparision: BaBar : ( ) Belle : ( ) 31

32 Combination of B + DK + and D + results LHCB-CONF If for first time also D + results are included: B D events: Preferred solution around 85 o consistent w/ unexpected positive asymmetry in B [ K ] D 32

33 = local minimum 33

34 B K K + K -, K + - LHCB-CONF B K K + K - B K K + K - B K + - B K

35 B + -, K + K - LHCB-CONF B B B - - K + K - B + + K + K - 35

36 Systematics LHCB-CONF LHCB-CONF

37 Phase space dependence LHCB-CONF B K K + K - B K + - large negative CPV at low m KK (region of resonances) large positive CPV at low m 37