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CP Violation and CKM Angles Status and Prospects

This presentation by Klaus Honscheid from Ohio State University at C2CR 2007 discusses the state of CP violation studies and the CKM matrix in particle physics. Highlighting two asymmetric energy B factories, PEP-II and KEKB, it delves into their roles in recording B decay events and measuring the unitary properties of the CKM matrix. The talk elaborates on the phenomenology of CP violation, with a focus on the analysis of B0→Kπ decays and quantum coherence effects in meson oscillations, emphasizing the implications for understanding fundamental symmetries in the Standard Model.

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CP Violation and CKM Angles Status and Prospects

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  1. CP Violation and CKM AnglesStatus and Prospects Klaus Honscheid Ohio State University C2CR 2007

  2. Two asymmetric-energy B factories 13 countries, 57 institutes, ~400 collaborators The Two Asymmetric Energy B Factories PEP-II at SLAC 9 GeV (e-)  3.1 GeV (e+) peak luminosity: 1.21034cm-2s-1 Belle BaBar KEKB at KEK 8 GeV (e-)  3.5 GeV (e+) peak luminosity: 1.71034cm-2s-1 11 nations, 77 institutes, ~600 persons K. Honscheid, Ohio State University, C2CR 2007

  3. Experimental Landscape (early 2007) Tevatron > 2.4 fb-1 # of B decays recorded 1.3 Billion 0.8 Billion Belle 710 fb-1 400 fb-1 BaBar Total Integrated Luminosity (fb-1) CLEO II.5 CLEO II K. Honscheid, Ohio State University, C2CR 2007

  4. CP Violation in the Standard Model CP Operator: coupling q’ q’ g g* CP( ) = q q J J Mirror To incorporate CP violation g ≠ g* (coupling has to be complex) K. Honscheid, Ohio State University, C2CR 2007

  5. CP Violation in the SM: The CKM Matrix • The CKM matrix Vij is unitary with 4 independent fundamental parameters • Unitarity constraint from 1st and 3rd columns: i V*i3Vi1=0 d s b u Vud Vus Vub Vcd Vcs Vcb Vtd Vts Vtb c t CKM phases (in Wolfenstein convention) a = p-g-b g ~ arg[Vub*] b ~ arg[Vtd*] K. Honscheid, Ohio State University, C2CR 2007

  6. Interfering Amplitudes in Bo Kp Decays Penguin decay Tree decay g G(B) – G(B) G(B) + G(B) A2 = a2e-if2 eid2 A1 = a1e-if1 eid1 |A|2 – |A|2 |A|2 + |A|2 Interference(A1+A2)2≠ (A1+A2)2 A1 = a1eif1 eid1 B0K-p+ + A2 = a2eif2 eid2 B0K+p- + ~ 2sin(f1 - f2) sin(d1 - d2) = 0 Asymmetry = = K. Honscheid, Ohio State University, C2CR 2007

  7. CP Violation in Bo Kp Decays BABAR background subtracted 227 x 106 B0 Mesons CountB0K+Decays 227 x 106 B0 Mesons CountB0K-+Decays Is N(B0K+) equal to N(B0K-+)? K. Honscheid, Ohio State University, C2CR 2007

  8. Mixing Induced CP violation B0 J/yKs ei0 B0 ei2b + Two Amplitudes Interference ACP ~ sin2b Golden mode B0J/yKs:CP eigenstate, high rate, theoretically clean No weak phase ei0 Two Vtd vertices ei2b K. Honscheid, Ohio State University, C2CR 2007

  9. A Complication: Quantum Coherence t =0 Dz = Dt gbc bg =0.56 l - (e-, m -) The two mesons oscillate coherently : at any given time, if one is a B0 the other is necessarily a B0 Dt picoseconds later, the B 0 (or perhaps its now a B 0) decays. In this example, the tag-side meson decays first. It decays semi-leptonically and the charge of the lepton gives the flavour of the tag-side meson : l -= B 0l+ = B 0. Kaon tags also used. (4S) We need to know the flavor of the B at a reference t=0 Flavor Tagging and measure the difference in decay time Dt Time Dependence At t=0 we know this meson is B0 B 0 rec B 0 B 0 tag Time dependent asymmetry ACP = SCPsin(DmDt)  CCPcos(DmDt) SCP = fCPsin2b (fCP= ±1), CCP “direct” CP violation = 0 forJ/yK K. Honscheid, Ohio State University, C2CR 2007

  10. CP Violation in B0J/yKs PRL 98, 031802 (2007) BaBar preliminary, hep-ex/0607107 Belle preliminary, hep-ex/0608039 B0J/yKL B0J/yKS Dt for B0 tag  B0J/yK Dt for B0 tag  B0J/yK Background Dt asymmetry J/yKLis fCP= +1 J/yKS is fCP= 1 Belle Preliminary Belle Preliminary B0 tags B0 tags B0 tags B0 tags Dt oscillation Period = B mixing Dm Amplitude = D sin2b (Dilution D due to mistags; measured experimentally) K. Honscheid, Ohio State University, C2CR 2007

  11. Sin(2b) World Average Statistics limited Consistent with zero: no evidence for NP in tree decay Heavy Flavors Averaging Group E.Barberio et al., hep-ex/0603003 b = 21.2o± 1.0o Extracting b from sin2b has ambiguities; removed by J/yK*, D*D*KS and Dp0/h/h'/w analyses K. Honscheid, Ohio State University, C2CR 2007

  12. Is “b” Universal? News Flash hep/ex 0702031 Possible contribution from New Physics (NP): new heavy particles in the loop See the following talk by Tom Browder BD+D- S = -1.12 ± 0.37 ± 0.09 A = 0.91 ± 0.23 ± 0.06 (= -C) (expected to be close to 0) Can use 3 different categories of B0 decays to measure b: golden mode K. Honscheid, Ohio State University, C2CR 2007

  13. Let’s try this for the next angle: a Tree decay B0B0mixing Penguin decay  Access to a from the interference of a b→u decay (g) with B0B0 mixing (b) g Inc. penguin contribution How can we obtain α from αeff ? Time-dep. asymmetry : NB : T = "tree" amplitude P = "penguin" amplitude K. Honscheid, Ohio State University, C2CR 2007

  14. How to estimate |a-aeff| : Isospin analysis • Use SU(2) to relate decay rates of different hh final states (h  {p,r}) • Need to measure several related B.F.s 2|-eff| Limiting factor in analysis Gronau, London : PRL65, 3381 (1990) K. Honscheid, Ohio State University, C2CR 2007

  15. Measuring a in Bpp hep-ex/0608035 hep-ex/0607106 +-  ±0 1464±65  0 0 Da Sp+p- = -0.61 ± 0.1 ± 0.04 Ap+p- (=-C) = 0.55 ± 0.08 ± 0.05 BRp+p- = (5.1±0.2±0.2) x 10-6 |Da|<41°@90% C.L. K. Honscheid, Ohio State University, C2CR 2007

  16. Sometimes you have to be lucky hep-ex/0607092 hep-ex/0607097 hep-ex/0607098 • B  rr is almost completely polarized • B r0r0 is small better constraint on Da B0r+r- B+r+r0 B0r0r0 615±57 390±49 K. Honscheid, Ohio State University, C2CR 2007

  17. Combining all methods: a Other solutions disfavoured CL=0.683 Combined:a = [93+119] Global fit without a: aGlobalFit = [ 98+5-19] º K. Honscheid, Ohio State University, C2CR 2007

  18. g = arg[Vub*]: CP violation in DK modes GLW: Gronau, London, Wyler (2001) ADS: Atwood, Dunietz, Soni (1997) GGSZ: Giri, Grossman, Soffer, Zupan (2003) E.g. B+D0 /D0K+ D decays do not involve Vub or Vtd: no contribution to phase ei0 ei0 D0K+ D0/D0 CP state (GLW) D0/D0Kp+/K+p, CA/DCS (ADS) D0/D0KSp+p, Dalitz(GGSZ) B+ V*ub vertex eig D0K+ eig ei0 Relative phase =eig B±  DK: no time dependence; extractgfrom rates and CP asymmetriesbut b  u amplitude is small (for example rB (DK−) = 0.16 ± 0.05 ± 0.01 ± 0.05 Belle) K. Honscheid, Ohio State University, C2CR 2007

  19. The GGSZ method – an example Look for deviations in B±D0K±plots Map out Dalitz plot from all D0 Ksp+p- decays B+ B Belle Belle BaBar preliminary; hep-ex/0607104 Belle; Phys.Rev.D 73, 172009 (2006) K. Honscheid, Ohio State University, C2CR 2007

  20. Combined Result for g Combined: g = [62+3824 ] Indirect (CKM) g = [59+94] K. Honscheid, Ohio State University, C2CR 2007

  21. The CKM Model has passed the experimental test [93 +11-9]o a g b (0,0) [62+38-24]o [21.2 ± 1.0]o New Targets • Effects of TeV new physics  deviations from SM • LFV and new source of CPV • Hidden flavor symmetry and its breaking K. Honscheid, Ohio State University, C2CR 2007

  22. The next few years (2007 – 2010) Belle and BaBar 1 ab-1 (2006) 2 ab-1 (2008) Tevatron 2 fb-1 (2006) 8 fb-1 (2009) LHCb is nearing completion ICHEP08 K. Honscheid, Ohio State University, C2CR 2007

  23. LHCb Prospects (Some of the things they can do) • Bs Mixing phase (s) using BsJ/ • Signal yield: 130k events per L=2fb-1 with a B/S0.1, Sensitivity s ~ 0.021 • Sensitive probe of New Physics effects in the Bs mixing • s = s(SM) + s(NP) with s(SM)=-2l2h ~ -0.037±0.002 V. Vagnoni CKM2006 LHCb atL=2fb-1 now now pre-LHCb LHCb at L=10fb-1 s(s) pre-LHCb LHCb at L=10fb-1 LHCb atL=2fb-1 year year • Sensitivity to g • Standard methods • Golden Mode Bs DsK • Sensitivity ~ 4.2o with 2 fb-1 now s(s) s(g) [o] pre-LHCb with LHCbat L=2fb-1 with LHCb at L=10fb-1 year K. Honscheid, Ohio State University, C2CR 2007

  24. From B-Factories to LHCb – without new physics 2014 Summer 2006 2008* LHCb L=10 fb-1 K. Honscheid, Ohio State University, C2CR 2007

  25. Super B-Factory Plans at KEK and Frascati ILC ring ILC FF IP Design Luminosity ~ 1 x 1036 /cm2/secSynergy with ILCRecycle components (PEP, BaBar)Lots of R&D needed New Beam pipe More RF power Interaction Region Crab crossing q=30mrad. by*=3mm New QCS Damping ring Linac upgrade L = 81035/cm2 /sec Frascati KEK K. Honscheid, Ohio State University, C2CR 2007

  26. Summary • CKM Model is now a tested theory • Great success for theorist • Great success for experimentalist • Great success for the Standard Model a = (93+11-9)o b = (21.2 ± 1.0)o g = (62+38-24)o • Search for Deviations from SM and New Physics • Near Term Future Looks Promising • B Factories only half way done • Tevatron will triple data sample • LHC(b) turn on • Long Term Prospects • LHC(b) upgrades • Super B Factories (KEK, INFN) K. Honscheid, Ohio State University, C2CR 2007

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