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ϕ 3 measurements at B factories

ϕ 3 measurements at B factories. Yasuyuki Horii Kobayashi- Maskawa Institute, Nagoya University, Japan Epiphany Conference, Cracow, 9th Jan. 2012. Experiments Contributing to ϕ 3 Determination. Belle e + e − collision at 10.6 GeV. BaBar e + e − collision at 10.6 GeV. CDF

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ϕ 3 measurements at B factories

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  1. ϕ3 measurements at B factories Yasuyuki Horii Kobayashi-Maskawa Institute, Nagoya University, Japan Epiphany Conference, Cracow, 9th Jan. 2012

  2. Experiments Contributing to ϕ3 Determination Belle e+e− collision at 10.6 GeV BaBar e+e− collision at 10.6 GeV CDF pp collision at 1.96 TeV LHCb pp collision at 7 TeV _ With charm inputs by CLEO, etc.

  3. CKM Matrix and Unitary Triangle • Charged-current interaction Lagrangian: • CKM matrix and unitary triangle: orthogonal

  4. CKM Parameters and ϕ3 • Precision on ϕ3 has been improved in recent years (20°10°). • Good agreement with measurements of other CKM parameters. Recent Result by CKMfitter Full Frequentist Method Recent Result by UTfit Bayesian Method ϕ3 = 68°+10°−11° ϕ3 = 74°±11°

  5. Definition and Golden Mode for ϕ3 • Definition: • Golden mode: BDK Only large complex element. L. Wolfenstein, PRL 51, 1945 (1983) Tree processes ϕ3 ~ −arg(Vub) • Color suppressed. • Final state contains D. _ • Color allowed. • Final state contains D.

  6. Method of ϕ3 Measurement _ ① B-D0K- D0f B- f K- φ3 _ _ B-D0K- D0f If no interference, angle disappears. ② Decay rate ∝ |A(①) + A(②)|2 • Exploit the interference betweenthe decay chains through D and D. • Angle ϕ3 (as well as strong phases)appears in the decay rates. • Several choices of the D decays: • DKK, ππ, KSπ0, KSφ, KSω, … (Gronau, London, and Wyler) • DKπ, Kππ0, … (Atwood, Dunietz, and Soni) • DKSππ, KSKK, … (Bondar, Giri, Grossman, Soffer, and Zupan)

  7. Current constraint on ϕ3 mainly obtained by GGSZwhile additional improvement is provided by GLW and ADS.

  8. GLW: Amplitude Triangles and Observables • Amplitude triangles: • Usually-measured observables: Magnitude of one sideis ~0.1 of the otherswhile relative magnitude ofthe others help ϕ3 constraint.

  9. GLW by Belle LP 2011 preliminary,772M BB CP+ (K+K−, π+π−): 582 ± 40 events CP− (KSπ0, KSη): 476 ± 37 events B-DCP+K- B+DCP+K+ B-DCP-K- B+DCP-K+ Red: signal Magenta: BDπ Green: BB BG Blue: qq BG (q=u, d, s, c) Light blue: peaking BG Significant CP asymmetry for CP+ mode. Opposite asymmetry btw CP+ and CP−. Systematics dominated by peaking BG.

  10. GLW by LHCb EPS 2011 preliminary,35.6 pb-1 • Result obtained by using data taken in 2010. Signal clearly seen. Promising result for obtaining nice RCP+/ACP+ at higher statistics.

  11. GLW up to 2010 BaBar, 467M BB, PRD82, 072004 (2010) CDF, 1 fb-1, PRD81, 031105(R) (2010) DCP+K− DCP−K− D(KK)K− D(KK)K+ DCP+K+ DCP−K+ D(ππ)K− D(ππ)K+ Opposite asymmetry btw CP+ and CP−. Consistent with the results of Belle. Good agreement with other measurements.

  12. Summary for GLW • All results for BDCPK obtained in 2010-2011. • Good agreement in measurements by different experiments. • CP violation clearly established for CP+ (ϕ3 information).

  13. ADS: Amplitude Triangles and Observables • Amplitude triangles: • Usually-measured observables: Magnitudes of the sides are small relatively to the GLW ones (small signal)while three sides of the triangleshave similar magnitudes (large CPV). Larger contribution from continuum BG. Additional parameters: Inputs from charm factories.

  14. ADS by Belle PRL106, 231803 (2011),772M BB • First evidence is reported byBelle with significance of 4.1σ. • Improved continuum suppressionwith NeuroBayes neural network. • Observables: • Indication of importantinformation for ϕ3 measurement: continuum Signal Dπ BB RADS and AADS varies in [0.2, 2.5] x 10-2 and [-0.9, 0.9], respectively, depending on ϕ3 and strong phases (assuming rB = 0.1).

  15. ADS by LHCb EPS 2011 Preliminary,343 pb-1 • LHCb also obtain evidence of ADS signal: 4.0σ significance Good agreement with the results of Belle.

  16. ADS by CDF Accepted by PRD(RC)in 2011, 7fb-1 • CDF also obtain evidence of ADS signal (3.2σ): Good agreement with other measurements.

  17. ADS D*K by Belle LP 2011 preliminary,772M BB • Continuum suppression with: • Signal seen with 3.5σsignificance for D*Dγ mode. • Ratio to favored mode: • Difference between RDπ0 and RDγ: indication of the effect of the interference term 2rB*rDcos(δB*+δD)cosϕ3 (opposite sign for RDπ0 and RDγ). continuum continuum Signal Signal D*π D*π DK/Dπ DK/Dπ BB BB

  18. ADS D*K by Belle LP 2011 preliminary,772M BB • Asymmetry: • Indication of opposite signfor ADπ0 and ADγ:consistent with expectation.(Opposite strong phasebetween D*Dπ0 and D*Dγ.) • Combining RDπ0, RDγ, ADπ0, and ADγ: indication of negative cos(δB*+δD)cosϕ3 and positive sin(δB*+δD)sinϕ3. Consistent with BD(*)K GGSZ result.

  19. Summary for ADS RADSfor DK AADSfor DK Signal established. Negative asymmetry. Promising for ϕ3 determination. RADSfor D*K AADSfor D*K Signal seen also for BD*K ADS. Encouraging for improving ϕ3 measurement.

  20. Additional Update: B0DK*0 ADS by Belle New772M BB • ADS method can be extended toB0DK*0 by tagging B0 from K*0. • K*0 cannot be separated by K+π−and effective parameters rS andδS are included in ‘ADS fit’. • Result: DK*0 qq Dρ BB No significant signal for main mode: 7.7+10.6-9.5. Both color suppressed. DK*0 Dρ qq BB Dh… Signal seen for calibration mode: 190+22-21. (NB’: variable for continuum suppression.)

  21. GGSZ, Model-Dependent Approach • Amplitude of B±DK± process can be expressed by • Procedure of analysis: • Fit tom± by M± to obtainx± = rBcos(±ϕ3+δB) and y± = rBsin(±ϕ3+δB). • Extract ϕ3 (as well as rB and δB) from x± and y±. Example:DKSπ+π− Amplitude of DKSh+h- decaydetermined from Dalitz plot of large continuum data(Flavor is tagged by soft-pion charge in D*±Dp±soft). Isobar-model assumption with BW for resonances.

  22. GGSZ by Belle PRD81, 112002 (2010),657M BB • Examples of Dalitz plots and confidence contours onxandy: • Result on ϕ3 obtained by combiningDK and D*K: B− B+ Dalitz plots for BDK. D decay modeling (isobar model)

  23. GGSZ by BaBar PRL105, 121801 (2010),468M BB Dalitz plots for BDK Contours for x and y BDK BD*K Effective hadronic parametersfor BDK* to take interference with other BDKS0π. BDK*

  24. GGSZ, Model-Independent Approach • Divide the Dalitz plot into several regions(averaged strong phase of DKShh obtained without assuming model). Number of events in ith bin is a function of x±/y± where ψ(3770) by CLEO DKSπ+π− Optimal binning: uniform divisionof the strong phase difference.(Binning is model-dependent while result model-independent.) Values of ϕ3, rB, and δB are extracted from Ni±’s(simultaneous equations for ϕ3, rB, and δB).

  25. GGSZ Model-Independent by Belle Moriond 2011 preliminary, 772M BB • Result of the fit of B±DK± sample in each bin: • Result on ϕ3 as well as contours on x and y: Black: flavor sample Third error due to ci and si uncertainty. Will decrease to 1° or less by BES-III.

  26. Summary • Recent improvement on ϕ3 (20°10°) is achieved by updates on BD(*)K(*)by Belle, BaBar, LHCb, and CDF. • GLW • CP asymmetry for CP+ mode established by BaBar and Belle. • ADS • Evidence of signal obtained by Belle, CDF, and LHCb. • Evidence also obtained for D*K by Belle. • GGSZ • First model-independent measurement by Belle. • Promising to obtain a precision of O(1°) in near future.

  27. 2ϕ1 + ϕ3 Belle, PRD84, 021101(R) (2011), 657M BB ± • Result of partial reconstruction for BD*π± published by Belle.(Preliminary result shown in 2008.) Mixing-induced CP violation to extract 2ϕ1 + ϕ3.

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