CP violation in the quark sector: What have we learned? Patricia Burchat, Stanford University World Summit on Physics Beyond the Standard Model Galapagos Islands, June 22-25, 2006 1 Notes for Printed Version of Presentation • I delivered this presentation on June 22, 2006, at the World Summit on Physics Beyond the Standard Model in San Cristobal Island, Galapagos. • I deliberately do not put much distracting text on my presentation slides. Therefore, the logic of the presentation may not be clear from this printed version. • This talk is not intended to be a review of heavy-flavor physics or CP violation. • For summarizing our current knowledge of results, I have relied heavily on the invaluable compilations by the Heavy Flavor Averaging Group, the CKMfitter Group, and the UTfit Group. • For most decays, I include the minimum number of Standard-Model or New-Physics Feynman diagrams needed to make a pedagogical point, rather than all possible diagrams. • This talk was prepared with Keynote and LaTeX Equation Editor (Mac OS X). 2 3 Last year’s World Summit on Evolution was a natural for the Galapagos. How can we compete?? • Evidence for CP Violation: difference in the time evolution of matter and anti-matter. • Evidence for Neutrino Mass: evolution of neutrino flavor in space and time. • Evidence for Dark Energy: unexpected evolution of the expansion rate of the universe. 4 Back to the Skeptics Society Excerpt from http://www.skeptic.com/about_us/discover_skepticism.html: Some people believe that skepticism is the rejection of new ideas, or worse, they confuse “skeptic” with “cynic” and think that skeptics are a bunch of grumpy curmudgeons unwilling to accept any claim that challenges the status quo. This is wrong. Skepticism is a provisional approach to claims. It is the application of reason to any and all ideas — no sacred cows allowed. In other words, skepticism is a method, not a position. Ideally, skeptics do not go into an investigation closed to the possibility that a phenomenon might be real or that a claim might be true. When we say we are “skeptical,” we mean that we must see compelling evidence before we believe. 5 Ideas to treat with healthy skepticism... • Supersymmetry: solution to the large quantum corrections to the Higgs mass. • R-parity conservation in SUSY: prevents proton decay -- and provides attractive Dark Matter candidate. • Cosmological Constant: solution to Dark Energy mystery? Motivation for best possible experimental investigation... 6 bd = B0 B Factories bu = B− Hadron machines bs = Bs (Tevatron, bc = Bc LHC) bud = Λb · · · 7 ≈ 1, 000, 000, 000 BB pairs served... CLEO 10M BABAR 360M Belle 600M ... plus ≈ 1, 000, 000, 000 cc pairs and ≈ 1, 000, 000, 000 τ +τ − pairs 8 Outline • Radiative decays • Direct CP violation • The angles α, β, γ • CP violation in b → sss decays with loops • → + − B(s) µ µ • Two recent results: 1. Observation of Bs mixing 2. Observation of B → τν • Putting it all together. 9 0 W χ˜ µ ˜ e˜ νµ νe µ x x γ γ e − 2 2 → 13 ∆mν −50 B(µ eee) could be of order 10 Suppressed by M 2 ≤ 10 ! ! W " with “New Physics” (e.g., MSSM). Experimental Results: B(µ → eγ) < 1.2×10−11, B(µ → eee) < 1.0×10−12 10 0 W χ˜ − τ ντ ν! ! τ˜ !˜ x x γ Experimental Results (BABAR and Belle): − B(τ → µγ) < 0.7 × 10 7 − B(τ → eγ) < 1.1 × 10 7 − B(τ → eee, µµµ, eµµ, µee) < (1 − 3) × 10 7 11 W d, u B K, K∗, Kπ, ... b t d, s ! χ˜0 q˜ 12 Keeping track of it all... Charmless B Branching Fractions Review of Particle Physics K0K0 CLEO CDF K+K0 HFAG Belle PDG2004 00 • 0 0 BABAR New Avg. April 2006 K+ K+ + + K 0 0 + K 0K 0 + 0 K + 0K 0 0 K +0 K+0 + + + + K KSKS K (NR) !+ K00 + K+0 K + + + K KSKSKS + !K+ K 0 0 + !K K + ! K +f + 0 + 0 0 K KK K + + K 0+ K KK + + 0 + + 0 K f0(980) 0 K+f (980) K 0 K0 + + K K + 0 + K 0 0 + 0 K0(1430) + K0(1430) 0 + 0.0 10.0 K0(1430) + 20.0 a1 + 0 K 0 + Heavy Flavor Averaging Group K + + K 0 • 0K + 0K 0.0 50.0 100.0 Branching Ratio x 106 • CKMfitter Group (primarily frequentist) • UTfit Group (primarily Bayesian) 13 (B X ! ) + B ! s d (B Xs` ` ) ! B ! HFAG CLEO HFAG Belle April 2006 BABAR April 2006 + PDG2004 New Avg. 0 CLEO Belle BABAR + p Kl l PDG2004 New Avg. + K0 K + K+ Ke e + 0 + K K e e + + K+ K 0 + K0 K 0 K+e+e K2(1430) + + K(892)l l K2(1430) + K+0 K(892) 0 + 0 + K K(892) 0 + K (892)++ K + + + K(892)e e K 0 + + 0 K(892) e e K + + K0+0 K(892) e e + + K(892) sl l + 0 s K(892) + + se e K1(1270) s 1/10 0.0 5.0 10.0 0.0 40.0 80.0 Branching Ratio x 106 Branching Ratio x 106 14 b → sγ BaBar ’05 Cleo ’01 Belle ’04 Neubert ’04 Buras et al. ’02 x 10-4 0 0.5 1 1.5 2 2.5 3 3.5 4 b " s! Branching Fraction BaBar ’05 * + - ∗ + − Belle ’04 B →K lKl ! ! Ali ’02 Zhong ’02 + - + − B →Kl lK! ! -5 !10 0 0.05 0.1 0.15 0.2 0.25 Branching Fraction 15 Outline • Radiative decays • Direct CP violation • The angles α, β, γ • CP violation in b → sss decays with loops • → + − B(s) µ µ • Two recent results: 1. Observation of Bs mixing 2. Observation of B → τν • Putting it all together. 16 0 + − W B → π K P B0 → π+K− + Is ( ) = 0 π P (B0 → π−K+)? B b Vub s − ∗ K Vus t V V ∗ tb ts u u d 17 0 + − W B → π K 0 + Two diagrams with π different weak phases ... B b Vub s − ∗ K Vus t V V ∗ tb ts u u d 18 0 + − W B → π K 0 + and different (uncalculable) π strong phases. B b Vub s − ∗ K Vus t V V ∗ tb ts u u d 19 Direct CP Violation 2 700 2 700 600 K!"! Belle 600 K!"! 500 500 400 400 300 300 Entries/2MeV/c Entries/2MeV/c 200 200 100 100 0 0 5.2 5.25 5.3 5.2 5.25 5.3 2 2 Mbc (GeV/c ) Mbc (GeV/c ) 700 700 600 World600Average: ! ! ! ! 500 0K " 500 K " Γ(B → π+K−) − Γ(B0 → π−K+) 400 400 0 + − 0 − + Entries/20MeV B → π K Entries/20MeV B → π K 300 Γ( 300) + Γ( ) 200 = −0.200108 ± 0.017 100 100 0 0 0 0.5 0 0.5 20 #E (GeV) #E (GeV) CP Asymmetries Measured in RCP areAsymmetry B inDecays Charmless B Decays +1.0 CLEO HFAG Belle + BABAR + 0 APRIL 2006 CDF 0 K + PDG2004 K + New Avg. + K ) ) + + 0 0 0 0 B B K + 0 K + ( ( K + + 0 0 + + + + + Γ Γ K K 0 K K + K K K K + ! + − 0 s ` + ! K + ) ) s` K B B ( ( 0.0 Γ Γ S + K + S + 0 + K + K K K K 0 0 0 + 0 f + K + K + K + -1.0 2 1 CP Asymmetry in Charmless B Decays +1.0 CLEO HFAG Belle + BABAR + 0 APRIL 2006 CDF 0 K + CP Asymmetries Measured in PDG2004 K + New Avg. K RCP areAsymmetry B inDecays Charmless B Decays + + + 0 0 0 +1.0 0 CLEO K HFAG + Belle 0 K + + K + BABAR + 0 APRIL+ 2006 0 0 + CDF 0 K + + + + + K PDG2004 + K K 0 New Avg. K K + K K + K + ) ) K + K + ! 0 0 0 0 B B K + 0 0 K + + ( ( K + ` ! K + s 0 0 + + + + + + Γ Γ K K 0 s` K K + K K K K + ! + − 0 K s ` + ! K + ) ) s` K B B ( ( 0.0 Γ Γ 0.0 S + K + S + 0 + K + K K S K K + K + 0 S 0 0 + + 0 + 0 K f + + K K K + K + K K K + 0 -1.0 0 0 + 0 f + K + K + K + -1.0 2 2 Outline • Radiative decays • Direct CP violation • The angles α, β, γ • CP violation in b → sss decays with loops • → + − B(s) µ µ • Two recent results: 1. Observation of Bs mixing 2. Observation of B → τν • Putting it all together. 23 The Quark Mixing Matrix and the Unitarity Triangle d s b u ∗ V V ∗ ub ud α V V c tb td γ β t ∗ VcbVcd apply unitarity constraint to these two columns 24 CP Violation observed in interference between decays with and without mixing. World Average: sin 2β = 0.69 ± 0.03 25 History of Statistical Uncertainty on sin2β in BABAR Statistical error on first measurement (2000) Expected reduction in statistical error due to increase in data sample size: 1 N BB ! ( ) 26 History of Statistical Uncertainty on sin2β in BABAR 27 The angle α: B → ππ: large penguin contributions; many ambiguities. B → ρπ: use interference in Dalitz plot. B → ρρ: small penguin contributions; longitudinal polarization dominates. +15 ◦ α = (100− 9 ) + 5 ◦ α = (97−16) 28 The angle γ from B+ → D(∗)K(∗)+: ! + 0(∗) + ! r ≡ A(B →D K ) Depends on B ! 0(∗) !. ! A(B+→D K+ ! GLW: B → DCP K ADS: B → DK±π± K B → D 0 + − K GGSZ: Ks π π ; Dalitz analysis ⇒ measure γ and rB.