Experimental Status of sin2β Measured from b s Penguin Decays. Mathew Graham SLAC FPCP06: Vancouver April 9, 2006

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1 Experimental Status of sin2β Measured from b s Penguin Decays Mathew Graham SLAC FPCP06: Vancouver April 9, 2006

2 Time-Dependent CP-Violation b B 0 A f W+ f CP A CP ( Δt) = Γ B f Γ B f ( ) Γ B f ( ) + Γ B f ( ) ( ) = 2Im λ 1+ λ sin Δm dδt 1 λ λ cos Δm dδt 2 b Bd 0 q 2 iβ p e B 0 W+ A f f CP S λ = η f q p C A A f f 2

3 Measuring sin2β with charmless B-decays J/ψ K 0 B 0 J/ψK 0 BR~ 10-3 sin2β=0.69±0.03 b d c,t s s φ s d K0 B 0 φk 0 B 0 BR~

4 Sources of Standard Model pollution There are many modes that dominantly decay via b s(qq) but not all modes were created equal B 0 b d b d c,t u u s d s d d B 0 K 0 K 0 This is ok; still gives sin2β in SM. d ω,π0,ρ 0,η (?),f 0 (?) ω,π 0,ρ 0,η (?),f 0 (?) CKM and color suppressed.. but will lead to slight deviation. 4

5 Expected deviations from sin2β QCDFA There are various estimates for the deviation from sin2β due to SM pollution most of them expect a larger value! S-sin2β 2-body: [Beneke; PL B620, 143 (2005)] 3-body: [Cheng,Chua,Soni; PRD72, (2005)] Measuring the rates of related modes help to pin down the magnitude of these deviations 5

6 Status of the B-Factories Belle : 500 fb 1 ; current results based on 357 fb 1 (almost) all results from hep-ex/ and are preliminary 330 fb 1 ; current results based on 210 fb 1 results come from variety of publications 6

7 Detecting a signal in general ΔE largest source of background comes from qq interactions use ΔE, m ES, and event shape to discriminate signal from background in case of quasi-2 body modes (φk 0, η K 0, etc) can also use invariant mass and helicity information = E B E beam B-Events qq Events M ES = E 2 beam p 2 B 7

8 Tagging the B and measuring Δt coherent BB production B-Flavour tagging Exclusive B meson reconstruction The Δt resolution function obtained from high stat. B DX Events tagged using the charge of the leptons, kaons, pions Effective tagging efficiency (including mistag-rate) ~30% 8

9 The golden mode: φk 0 Considered the golden mode because it s almost pure b sss Use both φk s and φk L N(φK s )=114 ± 12 N(φK L )=98 ± 18 Belle: N(φK s )=180 ± 16 N(φK L )=78 ± 13 φk s φk L φk s φk L No energy measurement for the K L constrain m ES to m B 9

10 The golden mode: φk 0 φk s φk L sin2β=0.50±0.25±0.06 C=0.00±0.23±0.05 Belle: sin2β=0.44±0.27±0.05 C=-0.14±0.17±0.07 φk s φk L fit both the Ks and KL samples to a common S/C good agreement between experiments! 10

11 NEW for 06 SM pollution to φk 0 : φπ φπ 0 φπ + N(φπ 0 )= 4.0 ± 3.5 N(φπ + )=-1.5 ± 5.9 BR(φπ 0 )<2.8x10-6 BR(φπ + )<2.4x

12 NEW for 06 SM pollution to φk 0 : K* 0 K s N(K* 0 K s )= 1.0 ± 4.3 BR(K* 0 K 0 +C.C.)<1.9x

13 K s K s K s The K s fly utilize the beam spot constraint in order to determine the vertex Allow (at most) one K s to decay to π 0 π 0 N(3K s )= 129 ± 13 Belle: N(3K s )=105 ± 12 13

14 K s K s K s time-dependent results one of the cleanest modes w/r to SM pollution also quite clean experimentally because of the 3K s s sin2β=0.63±0.30±0.04 C=-0.10±0.25±0.05 Belle: sin2β=0.58±0.36±0.08 C=-0.50±0.23±

15 NEW for 06 K s K s K L Excluding φk s Like KsKsKs, this is a very clean mode w/r to SM pollution the K L makes it more difficult experimentally N(K s K s K L )= 23.0 ± 23 ± Assuming phase space BR(K s K s K L )<6.4x No Assumptions BR(K s K s K L )<14x10-6 The prediction** for this mode is BR~6x10-6 **Cheng,Chua,Soni; PRD72, (2005) 15

16 K + K K 0 CP content Excluding φk s K + K - K 0 compliments φk 0 nicely with higher statistics two problems not in a definite CP eigenstate tree contribution to NR component Fortunately, this decay is almost entirely CP-even (for K s -mode) N(K + K - K s )=452 ± 28 f even =0.89 ± 0.08 ± 0.06 (moments) Belle: N(K + K - K s )=536 ± 29 f even =0.93±0.09±0.05 (SU2) 16

17 Excluding φk s K + K K 0 time-dependent results K + K - K s K + K - K s K + K - K L sin2β=0.41±0.18±0.07±0.11(cp) C=0.23±0.13 Belle: sin2β=0.60±0.18±0.04±0.16(cp) C=0.06±0.11±0.07 The BaBar result includes 777 ± 80 K + K - K L events(preliminary) 17

18 η K 0 : the second golden mode? very high statistics most models predict small SM pollution N(η K s )=804 ± 40 N(η K L )=440 ± 53 Belle: N(η K s )=830 ± 35 N(η K L )=187 ± 18 18

19 η K 0 time-dependent results η K s η K s η K L η K L sin2β=0.36±0.13±0.03 C=-0.16±0.09±0.02 Belle: sin2β=0.62±0.12±0.04 C=-0.04±0.08±

20 η K 0 SM pollution: η π 0,ηπ 0,η η All plots for η π 0 NEW for 06 These 3 modes help constrain the tree and colorsinglet penguin contributions to η K 0 Expectations for the BRs are ~0.2-2 x 10-6 new! BaBar result accepted by PRD-RC; hep-ex/ See talk by J. Smith for more details on η π 0 BR(η π 0 )<2.1x10-6 BR(ηπ 0 )<1.3x10-6 BR(η η)<1.7x10-6 Belle: BR(η π 0 )=(2.8±1.0±0.3)x10-6 BR(ηπ 0 )<2.3x

21 sin2β eff from B 0 π + π K s final states ρ 0 f 0 f??? quite a few CP events in this decay including ρ 0 K s and f 0 K s also a higher (f?) resonance ~1500 MeV there is a possible tree diagram which contaminates the sin2β measurement time-dep CP has been measured for f 0 K s and (now) ρ 0 K s Last summer, Belle presented a (time and tag independent) DP analysis of this mode this approach will be important in the future! 21

22 NEW for 06 ρks: a new mode N(ρK s )= 111 ± 19 Complications high bkg ρ is broad CP-even under the ρ? 22

23 NEW for 06 ρks results B 0 tags B 0 tags Asymmetry sin2β=0.17±0.52±0.26 C=0.64±0.41±0.25 A large source of error comes from the possible CP-even under the rho (including interference effects) still statistically limited 23

24 other modes.which I don t have time to go into detail about. Mode B 0 π 0 K s B 0 f 0 K s B 0 ωk s B 0 π 0 π 0 K s <sin2β eff > 0.31± ± ± ±0.72 Comments Novel vertexing technique SM pollution well understood? possible tree contribution; what s an f 0? tree contribution gives possibly large SM pollution Low stat BaBar only 24

25 Current status Taken on averge, there decent agreement with the SM expectation However, (almost) all measurements are lower than sin2β from J/ψK 0 most models predict SM pollution to increase sin2β eff 25

26 The future of sin2β eff summer 06?! looks good! The error on η Ks alone should get down to <5%! will remain statistics limited for foreseeable future 26