La Belle Epoque. K.Trabelsi kek.jp Lausanne, 22 Jan, 2009

Transcription

1 La Belle Epoque K.Trabelsi kek.jp Lausanne, Jan, 9 Belle Epoque : was a period in European social history that began during th the late 19 and lasted until World War I... considered as a golden age... wikipedia

2 Belle Collaboration

3 8 GeV e 3.5 GeV e

4 Motivations Overconstrain the CKM matrix : measure fundamental parameters, constrain new physics effects Measure the 4 free paremeters in various ways : CP conserving { V us, V cb, V td, V ub } CP violating { K, s,, } Tree level {...,..., V ub, } Loop level {...,..., V td, }... CP violating tree

5 B Factory Physics Programme Test the Standard Model mechanism for flavour changing quark interactions Multiple measurements of sides and angles of the Unitarity Triangle Studies of rare non tree decays B, Bs Exploit huge data samples to probe several complementary sectors charm, tau, Upsilon, spectroscopy,...

6 B factories: BaBar and Belle 1 Luminosity fb Luminosity Peak Integrated Luminosity Peak Integrated 1 cumulated stat : ~14fb /cm /s 84 fb fb at 4S /cm /s fb fb at 4S 5 publications!!

7 Timedependent CP asymmetries in decays to CP eigenstates N B t f N B t f A CP f ; t = N B t f N B t f = S sin md ta cos md t Im 1 = sin md t cos md t 1 1 A B f i A f q = =e p A B f Af i A = and S = f sin for cc K S/L f = 1 A = and S = sin for if tree only

8 Measuring the CP parameters S and A t / dpsig e t, q = 1 q S sin md t A cos md t dt 4 B B

9 Measuring the CP parameters S and A Reconstruct BCP t / dpsig e t, q = 1 q S sin md t A cos md t dt 4 B B

10 Measuring the CP parameters S and A Reconstruct BCP z~c t t / dpsig e t, q = 1 q S sin md t A cos md t dt 4 B B

11 Measuring the CP parameters S and A Reconstruct BCP Flavor tag z~c t t / dpsig e t, q = 1 q Ssin md t A cos md t dt 4 B B

12 J / K S and J/ K L B B pairs [PRL ] CP odd N sig = 748 Purity = 97 % CP even N sig = 651 Purity = 59 % sin =.643 ±.38 A =.1 ±.8 sin =.641 ±.57 A =.45 ±.33

13 sin 1 with J/ K : la raison d ' e tre of the B factories sin =.64 ±.31 ±.17 A =.18 ±.1 ±.14 PRL anchor point of the SM still statistically limited! irreducible syst ~.13

14 sin with S K S B B pairs [PRD ] S l l S J / CP odd Nsig = 139 Purity = 94 % sin =.7 ±.9 ±.3 A =.4 ±.7 ±.5 soon other charmonium modes c1 K S, c K S...

15 What is the source of CP violation? The Kobayashi - Maskawa phase is the source

16

17 in other modes increasing tree diagram amplitude increasing sensitivity to new physics possible new sources of CPV?

18 tcpv in D D decays 6 SM expectation : S sin, A 3 % Z.Z.Xing, PRD Nsig ~ 13 evts Purity = 6 % performed with B B S = 1.13±.37±.9 A =.91±.3±.6

19 tcpv in D D decays S, A = 1.1,.9 zero CP violation S=A= excluded at 4.1 CL [PRL98, 18 7 ] First evidence of CP violation in D D decays 3. of direct CPV? but not indicated by other measurements need to check other modes D D etc...

20 S and A in b cc d modes * ** * [ PRD77, ] ** [ PRL98, 18 7 ] good agreement with b cc s modes result S=sin, A= more info needed for A in D D mode

21 B D D mode B B pairs [arxiv : ] Br B D D = 3.85±.31± BaBar [PRD73, ] 3.8±.6±.5 14 Belle [PRL95, ] 4 4.8±.8±.6 1 B B A CP B D D =.±.8±. no direct CP observed Br B D D.4 9 %C.L.

22 increasing tree diagram amplitude increasing sensitivity to new physics PRD 67, ' ' sin ' ' =.73 ±.64±.

23 Measurements of 1 with penguins ' K S : Nsig = 141±46 ',, 3 KS, BB pairs [PRL ] ' ' sin ' ' =.64 ±.1 ±.4 A =.1 ±.7 ±.5 ' K L : Nsig = 454±39 ', 3 bckg subtracted Observation of TCPV in a single well - defined mode Results consistent with J/ K average

24 BB pairs [ ArXiv : ] KS NS = 1944±98 evts focus on the low M KK region and extract CP parameters f 98 KS K K NS = 169±51 evts ' ' ' ' = ±. ±. 1.4 ' ' sin ' ' = A = ±.4 ±.9

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26 1 with b s penguins summary More statistics crucial for mode - by - mode studies

27 determination : A t = = S 1A sin m t A cos m t sin eff sin m t A cos m t from time dependent CP, we can measure eff, but we want! Isospin analysis: [Gronau- London, PRL65, ] A + - A = A + A + - A = A + can be resolved up to an 8fold ambiguity : ~ 1% longitudinally polarized similar isospin analysis

28 : system 6 observables for 6 parameters Br B, S, A, Br B, Br B, A A =.55 ±.8 ±.5 S =.61 ±.1 ±.4 Direct 5.5 PRL 98,181 7 difference is now 1.9 = 97±11 standard 1

29 system 5 observables for 6 parameters Br B, S, C, Br B, Br B f L PRD 76,1114 R % C.L. BR B? from BaBar [PRD78, ].9±.3± significance.11 f L = ±.5 A =.16 ±.1 ±.7.7 S =

30 mode 4 MC B B pairs [arxiv : ] MC Data MC 4dim E, M bc, M, M fit : 1. significance 6 BR B =.4± % C.L..5 significance 6 BR B 4 = 1.4± %C.L. BR is small! SU triangle even more squashed

31 ± measurements from B DK ± Theoretically pristine B DK approach Access via interference between B D K and B D K color allowed * B D K ~ V cb V us ~A 3 color suppressed * B D K ~ V ub V cs ~ A 3 i relative magnitude of suppressed amplitude is r B A suppressed V ub V *cs rb= ~ [color supp] =.1 -. * A favoured V cb V us relative weak phase is, relative strong phase is B

32 ± measurements from B DK ± Reconstruct D in final states accessible to both D and D D = DCP, CP eigenstates as K K,, K S GLW method Gronau - London - Wyler D = Dsup, Doubly - Cabbibo suppressed decays as K ADS method Atwood- Dunietz - Soni Three- body decays as D K S, K S K K GGSZ Dalitz method Giri - Grossman - Soffer - Zupan Largest effects due to charm mixing charm CP violation negligible [PRD 7, ] Different B decays DK, D* K, DK * different hadronic factors r B, B for each

33 * B D K * Dalitz analysis Reconstruction of threebody final states D, D K S Amplitude for each Dalitz point is described as: D K S ~ f m, m D K S ~ f m, m B K S D K : f m, m r e m m =M K S m =M K S i B f m, m m D D m i B K S D K : f m, m r e f m, m m Simultaneous fit of B and B to extract parameters r B, 3 and B Note : fold ambiguity on :, B, B

34 Sensitivity to sensitivity to / 3 varies across the Dalitz plot =75, =18, rb =.15 DCS K * 143 DCS K * 89 w=1/ d L /d GLW like Interference of B D K, D K S with B D K, D K S ADS like Interference of B D K, D K *+ with B D K, D K *+

35 * Dalitz B D K S K B B pairs [arxiv : ] * DK x± = r B cos B ± y ± = r B sin B ± * D K, D D = = 63.8 ±5. ±8.7 r B =.161 ±.11±.49 B = ±4. ± = 76 ±4.7 ±8.7 r B =.8 ±.15±.49 B = 34. ±3.7 ±.9 stat ±4 syst ±9 model

36 * Dalitz B D K S K B B pairs [arxiv : ] * DK x± = r B cos B ± y ± = r B sin B ± * D K, D D = = 63.8 ±5. ±8.7 r B =.161 ±.11±.49 B = ±4. ± = 76 ±4.7 ±8.7 r B =.8 ±.15±.49 B = 34. ±3.7 ±.9 stat ±4 syst ±9 model

37 Dalitz B DK x± = r B cos B ± y ± = r B sin B ± DK, BaBar DK, Belle = 8.8 r B =.161 B = ±5. ±8.7 ±.11±.49 ±4. ±.9 ~ 63 ±8 r B =.86 ± B = 19

38 * Dalitz B D K S K B B pairs [arxiv : ] * DK x± = r B cos B ± y ± = r B sin B ± * D K, D D = = 63.8 ±5. ±8.7 r B =.161 ±.11±.49 B = ±4. ± = 76 ±4.7 ±8.7 r B =.8 ±.15±.49 B = 34. ±3.7 ±.9 stat ±4 syst ±9 model

39 ADS method : D K interfering amplitudes are comparable introduce new parameters: r D, D but measured by CLEO BESIII continuum background dominates

40 ADS method D K B B pairs [PRD 78, ] same B, rb additional parameters D, r D 7.7 NS = = 1.5 continuum No signal observed yet, limit on r B :.19 at 9 % C.L.

41 * sin from B D decay Use B flavor tag, measure time - dependent decay rates 1 t / ± e [1 C cos m t S sin m t ] 8 B 1 t / * ± ± P B D = e [1 ± C cos m t S sin m t ] 8 B * ± P B D = B B ± S = r sin ± D * 1r C= 1 1r r. large stat available, small CP violation effect

42 * D with partial reconstruction BB pairs [ ArXiv : 89.33] partial reconstruction helps increase statistics lepton tag 5196±86 signal evts S =.57±.19±.1 S =.38±.±.1 HFAG notation a = S S / c = S S / a =.47±.14±.1 c =.9±.14±.1 significance of CPV is.6

43 * sin from B D decay summary for all measurements partial and full significance of CPV is ~4

44 Summary for the Angles 6.1 = WA, CKMfitter, summer8 = WA, CKMfitter, CKM8 = 1.1±.9 WA, HFAG, ICHEP8

45 b s, b d, b s l l, B forbidden at tree level

46 Branching ratio for fully inclusive B X s CM Find isolated clusters in calorimeter with E 1.4 GeV BB pairs [ ArXiv :84.158] Veto photon from,, and Bhabha Suppress continuum background using topology, subtract the remainder Subtract non - primary photons using data to correct MC spectra 6 ON resonance scaled OFF resonance continuum - subtracted signal secondaries Data signal MC

47 Branching ratio for fully inclusive B X s BB pairs [ ArXiv : ] Extracted photon energy spectrum of B X s, d 1.7 GeV Ecms.8 GeV ~97 % of total spectrum Correction to subtract X d component R d /s= 4.±.4 % BR B X s E B 4 = 3.31±.19± GeV

48 Branching ratio for B X s 4.98± ±.3 1

49 Operator product expansion for b s l l 1 Heff i=1 Ci Oi Short - distance Wilson coefficients: C C eff 7 eff 9.33 from photon penguin eff complementary to B X s C1 from vector axial - vector part of box

50 BB pairs * B K l l [ ArXiv :81.335] Exlusive modes K : K, K S, K * K, K S, K K * * J/ and K ' are excluded, used as control sample assuming lepton flavor ratio e/ 1.33 K *, 1. K Differential BF * K l l K l l NS = 166±15 NS = 33 4 R K =1.1±.5±.8 R K =.97±.18±.6 * theory prediction.5 7 BR = ± BR = ±.9 1 consistent with SM expectations Ali et al : PRD66, 34

51 BF is not sensitive to new physics due to theory uncertainty Many other observables are sensitive to new physics especially as functions of q = m l l * K polarization Forward Backward asymmetry d 3 3 = FL cos K 1FL sin K d cos K 4 * * * d = d cos Bl 3 3 FL sin Bl 1FL 1cos Bl A FB cos Bl 4 8 Standard Model C7 = CSM Kruger and Matias:PRD 71,

52 [ ArXiv :81.335] * Isospin asymmetry in B K l l AI = B / B BR K * l l BR K * ± l l B / B BR K * l l BR K * ± l l Mode K l l q 8.68 GeV /c ± K * l l.9 ±.16 ± K * l l ±.4

53 B SM: 1.59±.4 14 assuming V ub = [incl. charmless semi - lep] f B =.16±. GeV GF m B m m BR B = 1 f B V ub B 8 mb hadronic tag BB pairs [PRL ] Extra calorimeter energy : E ECL Tag side : * B D *,D *,D * a1, D * Ds Signal side :, e,,, Nsig = evidence First evidence! BR B = [dominant syst : background shape, tag rec. eff.]

54 B BB pairs [ ArXiv : ] semi - leptonic tag * BR B D l is large 17% S/N worse than with hadronic B tags D* / l, D l Signal side : 1 prong decay e e,, 1 Nsig = significance EECL GeV BR B = Charged Higgs contribution enhances/reduces the BR : BR B = BR B SM r H r H = 1 mb m H tan constraint on m H vs tan

55 Summary Belle continuing to produce a wealth of results in a wide range of topics No smoking gun for new physics BUT several interesting hints strong constraints for model builders powerful motivation for better measurements LHCb & Super Flavour Factory Expect more including more surprises from Belle as final data sets are analyzed and new data more 5S will be taken

56 Backup slides

57 3.1 significance BR B =.9±.3± significance BR B =.9±.3± SL =.3 ±.7 ±. CL =. ±.8 ±.3

58 constraint

59 and r B... BaBar example analysis with 7 16 BB [PRL95, ] r B DK =.1 ±.8 ±.3 ±.4 = 7 ±31 stat 1 1 syst model r B DK.14 analysis with BB [ hepex / 6714 ] = 9 ±41 stat ±11 syst ±1 model uncertainty on scales as 1/r B! r B = no constraint on DK case r B =.1 r B =.7 r B =.16 the r B assumption for the extrapolation is very relevant as the stat increases, the sophisticate statistical treatment not necessary anymore

60 GLW method no charge asymmetry yet observed BaBar ~35 fb1, Belle ~5 fb1 observables R CP, A CP ± ±

61 Predictions for LHCb MC Data LHCb Belle 1 Luminosity fb 65 B Dfav K yields 8, 1,

62 Improved measurements of B and First observed by Belle, confirmed by BaBar, now with 1.7 data BB [PRL 96, ] * B K is a severe background K - id fake rate Br B /Br B K * MK is now in the fit for B Mbc - E -MK fit MK : mass with mk assignment for / E : separation of ~ 5 MeV Excellent sample to fix signal and background shape 17 B 7616 events [PRL 11, ]

63 Improved measurements of B and 15 B Br B B ±1.3.6 B 8 B 177 events B 4614 events ± B, 11.4± Combined Br with assumption : B, = B = B = B = B, form factor ratio R, isospin violation factor 3 V 1m /m Br B, td, B R= = [1 R ] * 3 V ts 1m K /mb Br B K *

64 CPV in B First CPV in b d! S ~ in SM arg V td in mixing and decay cancel suppression due to photon polarization A could be nonzero in SM [PRL 1, 16 8 ] S =.83±.65±.18, A =.44±.49±.14

65 B V B K * charged and neutral charged and neutral, BS, asymmetry in B

66 B, results Belle BaBar this summer result PRL98, B Br B 7.6±1.7± B ±.4.6 B 11.9±.4± B, 11.3±.± Belle PRL 96, B B B Br B, Br ± ± ± ± ±.9

67 B X s l l

68 Correlations of C7, C9 and C1 new - physics shits

69 B versus sin

70 B K S

71 * B Bpairs B D [PRL ] W, H * D D, D K e e, Other B fully reconstructed c b Nonzero missing mass, small E vis X mis= signal * D Ebeam ED Ee, p pe, * * E * * beam D e MB Measure the Btag yield signal First observation! BR B D *.4 =..37 ±.37 %