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CP Violation and CKM Angles Status and Prospects Klaus Honscheid Ohio State University C2CR 2007
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K. Honscheid, Ohio State University, C2CR 2007 PEP-II at SLAC KEKB at KEK Belle BaBar 9 GeV (e ) 3.1 GeV (e + ) peak luminosity: 1.2 10 34 cm 2 s 1 Two asymmetric-energy B factories 8 GeV (e ) 3.5 GeV (e + ) peak luminosity: 1.7 10 34 cm 2 s 1 11 nations, 77 institutes, ~600 persons 13 countries, 57 institutes, ~400 collaborators The Two Asymmetric Energy B Factories
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K. Honscheid, Ohio State University, C2CR 2007 Experimental Landscape (early 2007) Total Integrated Luminosity (fb -1 ) CLEO II CLEO II.5 BaBar Belle 710 fb -1 400 fb -1 Tevatron > 2.4 fb -1 # of B decays recorded 1.3 Billion 0.8 Billion
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K. Honscheid, Ohio State University, C2CR 2007 CP( ) = CP Violation in the Standard Model CP Operator: q q’ J g q JJ g* Mirror coupling To incorporate CP violation g ≠ g* (coupling has to be complex)
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K. Honscheid, Ohio State University, C2CR 2007 CP Violation in the SM: The CKM Matrix The CKM matrix V ij is unitary with 4 independent fundamental parameters Unitarity constraint from 1st and 3rd columns: i V * i3 V i1 =0 CKM phases ( in Wolfenstein convention ) u d t c bs V ud V us V ub V cd V cs V cb V td V ts V tb arg[V ub *] arg[V td *]
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K. Honscheid, Ohio State University, C2CR 2007 Interfering Amplitudes in B o K Decays B 0 - + B 0 + - A 1 = a 1 e i 1 e i 1 A 1 = a 1 e -i 1 e i 1 Asymmetry = = ~ 2 sin( ) sin( 2 ) = 0 A 2 = a 2 e i 2 e i 2 A 2 = a 2 e -i 2 e i 2 + + |A| 2 – |A| 2 |A| 2 + |A| 2 (B) – (B) (B) + (B) Tree decay Penguin decay Interference (A 1 +A 2 ) 2 ≠ (A 1 +A 2 ) 2
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K. Honscheid, Ohio State University, C2CR 2007 227 x 10 6 B 0 Mesons Count B 0 K + Decays 227 x 10 6 B 0 Mesons Count B 0 K - + Decays Is N( B 0 K + ) equal to N( B 0 K - + )? CP Violation in B o K Decays BABAR background subtracted
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K. Honscheid, Ohio State University, C2CR 2007 Golden mode B 0 J/ K s :CP eigenstate, high rate, theoretically clean Mixing Induced CP violation B0B0 J/ K s e i0 e i0 No weak phase B0B0 e i2 Two Amplitudes InterferenceA CP ~ sin2 Two V td vertices e i2 +
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K. Honscheid, Ohio State University, C2CR 2007 (4S) t =0 A Complication: Quantum Coherence We need to know the flavor of the B at a reference t=0Flavor Tagging and measure the difference in decay time tTime Dependence B 0 The two mesons oscillate coherently : at any given time, if one is a B 0 the other is necessarily a B 0 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 0 l = B 0. Kaon tags also used. tag B 0 l (e-, -) =0.56 z = t c rec t picoseconds later, the B 0 (or perhaps its now a B 0 ) decays. B 0 At t=0 we know this meson is B 0 Time dependent asymmetry A CP = S CP sin( m t) C CP cos( m t) S CP = f CP sin2 (f CP = ±1), C CP “direct” CP violation = 0 for J/ K
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K. Honscheid, Ohio State University, C2CR 2007 CP Violation in B 0 J/ K s t for B 0 tag B 0 J/ K Background BaBar preliminary, hep-ex/0607107 Belle preliminary, hep-ex/0608039 B 0 J/ K S B 0 J/ K L Belle Preliminary Belle Preliminary B 0 tags t asymmetry J/ K L is f CP = +1 J/ K S is f CP = 1 t oscillation Period = B mixing m Amplitude = D sin2 (Dilution D due to mistags; measured experimentally) PRL 98, 031802 (2007)
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K. Honscheid, Ohio State University, C2CR 2007 Extracting from sin2 has ambiguities; removed by J/ K*, D* D *K S and D 0 / / '/ analyses Sin(2 ) World Average Heavy Flavors Averaging Group E.Barberio et al., hep-ex/0603003 Statistics limited Consistent with zero: no evidence for NP in tree decay = 21.2 o ± 1.0 o
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K. Honscheid, Ohio State University, C2CR 2007 Is “ ” Universal? Can use 3 different categories of B 0 decays to measure : golden mode Possible contribution from New Physics (NP): new heavy particles in the loop See the following talk by Tom Browder News Flash hep/ex 0702031 B D + D - S = -1.12 ± 0.37 ± 0.09 A = 0.91 ± 0.23 ± 0.06 (= -C) (expected to be close to 0)
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K. Honscheid, Ohio State University, C2CR 2007 Let’s try this for the next angle: Access to from the interference of a b → u decay ( ) with B 0 B 0 mixing ( ) B 0 B 0 mixing Tree decayPenguin decay Inc. penguin contribution How can we obtain α from α eff ? Time-dep. asymmetry : NB : T = "tree" amplitude P = "penguin" amplitude
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K. Honscheid, Ohio State University, C2CR 2007 How to estimate | eff | : Isospin analysis Use SU(2) to relate decay rates of different hh final states (h { }) Need to measure several related B.F.s Gronau, London : PRL65, 3381 (1990) 2| eff | Limiting factor in analysis
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K. Honscheid, Ohio State University, C2CR 2007 Measuring in B hep-ex/0607106 ±0 ±0 0 0 0 0 °@90% C.L. hep-ex/0608035 1464±65 S + - = -0.61 ± 0.1 ± 0.04 A + - (=-C) = 0.55 ± 0.08 ± 0.05 BR + - = (5.1±0.2±0.2) x 10 -6 +-+-
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K. Honscheid, Ohio State University, C2CR 2007 Sometimes you have to be lucky 615±57 390±49 B is almost completely polarized B is small better constraint on hep-ex/0607092 hep-ex/0607097 hep-ex/0607098 B B B B B B
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K. Honscheid, Ohio State University, C2CR 2007 Combining all methods: Combined: = [93 +11 9 ] CL=0.683 Other solutions disfavoured Global Fit = [ 98 +5 -19 ] º Global fit without :
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K. Honscheid, Ohio State University, C2CR 2007 = arg[V ub *]: CP violation in DK modes Relative phase = e i B+B+ D0K+D0K+ eiei eiei V* ub vertex e i E.g. B + D 0 / D 0 K + D0K+D0K+ D 0 / D 0 CP state (GLW) D 0 / D 0 K + /K + , CA/DCS (ADS) D 0 / D 0 K S + , Dalitz (GGSZ) D decays do not involve V ub or V td : no contribution to phase GLW: Gronau, London, Wyler (2001) ADS: Atwood, Dunietz, Soni (1997) GGSZ: Giri, Grossman, Soffer, Zupan (2003) eiei eiei B ± DK: no time dependence; extract from rates and CP asymmetries but b u amplitude is small (for example r B (DK − ) = 0.16 ± 0.05 ± 0.01 ± 0.05 Belle)
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K. Honscheid, Ohio State University, C2CR 2007 The GGSZ method – an example BaBar preliminary; hep-ex/0607104 Belle; Phys.Rev.D 73, 172009 (2006) Belle Map out Dalitz plot from all D 0 K s + - decays B+B+ BB Look for deviations in B ± D 0 K ± plots
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K. Honscheid, Ohio State University, C2CR 2007 Combined Result for Indirect (CKM) = [59 +9 4 ] Combined: = [62 +38 24 ]
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K. Honscheid, Ohio State University, C2CR 2007 The CKM Model has passed the experimental test New Targets Effects of TeV new physics deviations from SM LFV and new source of CPV Hidden flavor symmetry and its breaking [21.2 ± 1.0] o (0,0) [93 +11 -9 ] o [62 +38 -24 ] o
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K. Honscheid, Ohio State University, C2CR 2007 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
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K. Honscheid, Ohio State University, C2CR 2007 LHCb Prospects (Some of the things they can do) B s Mixing phase ( s ) using B s 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 B s mixing s = s (SM) + s (NP) with s (SM)=-2 2 ~ -0.037±0.002 now pre-LHCb LHCb at L=2fb -1 LHCb at L=10fb -1 year (s)(s) now pre-LHCb LHCb at L=2fb -1 LHCb at L=10fb -1 (s)(s) Sensitivity to Standard methods Golden Mode B s D s K Sensitivity ~ 4.2 o with 2 fb -1 ( ) [ o ] now pre-LHCb with LHCb at L=2fb -1 with LHCb at L=10fb -1 year V. Vagnoni CKM2006
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K. Honscheid, Ohio State University, C2CR 2007 Summer 2006 From B-Factories to LHCb – without new physics 2008* LHCb L=10 fb -1 2014
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K. Honscheid, Ohio State University, C2CR 2007 Super B-Factory Plans at KEK and Frascati Interaction Region Crab crossing =30mrad. y*=3mm New QCS Linac upgrade More RF power Damping ring New Beam pipe L = 8 10 35 /cm 2 /sec Design Luminosity ~ 1 x 10 36 /cm 2 /sec Synergy with ILC Recycle components (PEP, BaBar) Lots of R&D needed KEK Frascati IPIP ILC ring ILC FF
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K. Honscheid, Ohio State University, C2CR 2007 Summary CKM Model is now a tested theory Great success for theorist Great success for experimentalist Great success for the Standard Model = (93 +11 -9 ) o = (21.2 ± 1.0) o = (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)
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