CKM phase and CP Violation in B Decays
CKM phase and CP Violation in B Decays l l l David Brown Lawrence Berkeley National Lab Ba. Bar Collaboration August 14, 2007 D. Brown, CKM phase and CP Violation in B Daegu, Korea. Decays
Talk Outline l l l l Review of CPV in the B system Results on the CKM unitarity angle = 1 Results on the CKM unitarity angle = 2 Results on the CKM unitarity angle = 3 Results on the Bs phase angle s Results on Direct CPV Conclusions I will concentrate on (some) New Results 2 D. Brown, CKM phase and CP Violation in B Decays
Quark-Sector Flavor in the SM l 3 known generations of quark doublets (u, d) (c, s) (t, b), EM charge (2/3, -1/3) l Origin of families unknown in SM l l l Only the charged-current EW interaction can change flavor in the SM EW eigenstates aren’t mass eigenstates l Only SM connection between generations! VCKM 3 D. Brown, CKM phase and CP Violation in B Decays
The CKM matrix l Relates EW flavor and quark mass eigenstates l l 3 generations, Unitarity 3 rotations, 1 phase l l No prediction of values within SM Non-zero phase implies CPV in flavor transitions New Physics (NP) with non-SM flavor couplings would make the CKM description incomplete l Eg: 4 th generation, SUSY, … Wolfenstein parameterization Vud Vus Vub VCKM = Vcd Vcs Vcb Vtd Vts Vtb 4 1 - 2 = - 1 - 2/2 A 3( -i ) A 2 A 3(1 - -i ) -A 2 1 ≈0. 23, A≈0. 8, ≈0. 2, ≈0. 4 D. Brown, CKM phase and CP Violation in B Decays + O( 4)
The Unitarity Triangle(s) l Graphical expression of unitarity condition(s) l l 1 triangle has roughly equal-length sides CKM Unitarity violation would imply New Physics l Test SM + CKM by over-constraining angles and sides h 5 -i D. Brown, CKM phase and CP Violation in B Decays
Consequences of CPV l CPV can occur when multiple B F amplitudes interfere CPV in decay (direct CPV) l CPV in mixing (original CPV seen in KS, KL) l l Very small for B system (exp. limit <10 -2, predicted ~10 -3 in SM) CPV in mixing + decay (indirect CPV) B system uniquely situated for CPV studies l Mixing, long lifetime, large production X-section, rich decay set, heavy quarks theoretically accessible, … Direct CPV B 0 and B EW 1 S 1 Mixing+Decay CPV B e-2 i 0 EW 2 S 2 6 CP † S 1 EW 1 † †≠ A S 2† EW 2† de F ca y D. Brown, CKM phase and CP Violation in B Decays B 0 0 AF FCP d y a c e
Detecting Indirect CPV in B-decays Coherent evolution B-factories e- e+ (4 S) B 0(b) K- m+ mix ing z≈ c t 7 Flavor tagging Q≈30% at B-factories ≈few % at Tevatron e- m- + - D. Brown, CKM phase and CP Violation in B Decays B f. CP exclusive reconstruction ~10%
The B-factories l Asymmetric e+e- colliders make boosted (4 S) l l General-purpose detectors l l Tracking EM calorimetery, muon system, PID, … Ba. Bar/PEP-II Total Sample ≈ 450 fb-1 KEK-B/Belle Total Sample ≈ 700 fb-1 Data sets have increased ~10% in the last year l l c B~200 m in the lab frame Many new results from data ‘backlog’! Tevatron Run 2 results on ≥ 1 fb-1 coming out now 8 D. Brown, CKM phase and CP Violation in B Decays
Beta B 0 h 9 D. Brown, CKM phase and CP Violation in B Decays
B 0 charmonium K 0: b c cs f= CP eigenvalue = -1(KS), +1(KL) No EW phase l SM decay dominated by a single tree diagram l Leading order (Tree) diagram has no weak phase l l Higher-order diagrams are smaller by factor ~O(10 -2 10 -3) l l l asymmetry directly measures most have same EW phase BF ≈10 -3 (color suppressed) SM expectation: S = - f sin 2 C≈0 10 D. Brown, CKM phase and CP Violation in B Decays
B 0 charmonium K 0: b c cs NB B = 535 M Nsig = 7484± 87 NB B = 383 M Nsig = 4748 Purity=55% background PRL 98, 031802 (2007) hep-ex/0703021 MB (Ge. V/c 2) l Easily reconstructed final states l Charmonium l+l- has high efficiency, low background l l background KS + - easily recognized in tracking detectors Strong kinematic variables separate B from background MB constrained to known beam energies to improve resolution l E EB-Ebeam is an independent kinematic variable l 11 D. Brown, CKM phase and CP Violation in B Decays
sin 2 in B 0 → charmonium K 0 : b c cs J/ KS NB B = 383 M NB B = 535 M B 0 tags J/ KL background PRL 98, 031802 (2007) Ba. Bar Preliminary (hep-ex/0703021) t (ps) 12 D. Brown, CKM phase and CP Violation in B Decays f t (ps)
from B 0 → charmonium K 0 : b c cs Sf = sin 2 95%CL contours Sin 2 =0. 678± 0. 026 New world average Sets the gold standard for CPV measurements 13 2 -fold ambiguity resolved by several cos 2 measurements new B 0 → D 03 -bodyh 0 Dalitz Analysis (Ba. Bar) B 0 → KS + - Dalitz Analysis (Ba. Bar) B 0 → KSK+K- Dalitz Analysis (Ba. Bar) + older results on B 0 → J/ K*, … D. Brown, CKM phase and CP Violation in B Decays
B 0 → D+D- : b → c cd D- NP particle can enter in loop DD+ B 0 l B 0 Two decay amplitudes interfere D+ Standard Model predicts: b → c tree diagram with S = -sin 2 l b → d penguin diagram with S ~ 0 l l Penguin is expected to be small l l ~2 -10% (PRD 61, 014010, 2001) Larger backgrounds Y. Grossman and M. Worah, Phys. Lett. B 395, 241 (1997) 14 D. Brown, CKM phase and CP Violation in B Decays
S and C in B 0 → D+D- : b → c cd C B 0 tags (0, 0) NB B = 383 M Nsig =131± 14 B 0 tags NB B = 535 M Nsig =128± 14 background Belle claims evidence for direct CP violation at 3. 2 S CCP(B 0 D+D-) = -0. 91 ± 023 ± 0. 06 CCP(B 0 D+D-) = +0. 11± 022 ± 0. 07 hep-ex/0702031 PRL 98, 221802(2007) Agreement on C has CL=0. 003 ⇒ >3. 0σ discrepancy 15 New Belle Result: ACP(B+ D+D 0) = 0. 01 ± 0. 08 ± 0. 02 BELLE-CONF-0762 Preliminary D. Brown, CKM phase and CP Violation in B Decays
CPV in B 0 → D*+D*- : b → c cd l Same diagram as B 0 → D+D-, but Vector-Vector final state l f (CP) depends on helicity, analyzed using D* decay angles Ba. Bar preliminary NB B = 383 M Nsig =617± 33 background hep-ex/0708. 1549 16 D. Brown, CKM phase and CP Violation in B Decays
S and C in b → c cd -Sf Cf sin 2 Silver modes: generally good agreement with golden mode S= -sin 2 C=0 17 D. Brown, CKM phase and CP Violation in B Decays
Purely Penguin decays: b s qq SM New Physics s q q l q New Physics can enter at equal order as SM Comparison with charmonium sin 2 provides a direct test for NP Many accessible modes l l SUSY, … SM predicts same EW phase as b → c. Wl l q No tree-level contributions l l s NP might couple to some or all More challenging experimentally l BF ~10 -5, large backgrounds from continuum 18 D. Brown, CKM phase and CP Violation in B Decays
B 0 → KS 0 0 : b s qq LR>0. 9 (Spherical) LR>0. 9 (Jet-like) Nsig = 307± 32 LR LR>0. 9, good tag B 0 tags MB(Ge. V/c 2) NB B = 657 M E(Ge. V) Preliminary S =+0. 43 ± 0. 49 ± 0. 09 C=+0. 17 ± 0. 24 ± 0. 06 BELLE-CONF-0723 t (ps) 19 2. 0 from the SM expectation S= -sin 2 t (ps) D. Brown, CKM phase and CP Violation in B Decays
B 0 → KS + - : b s qq l Measure TDCPA at each point on the Dalitz plot l Include interference between + -, KS ± resonances l l l 0, f 0, K*, … Supersedes previous results on B 0 → KS , KSf 0 + Direct CPV in B 0 → K*+ relative phases 2 2 B 0 → KSf 0(980) B 0 → KS (770) 2 eff hep-ex/? ? 2 eff 2. 1 > 2 from charmonium 2 -fold ambiguity (partially) resolved 20 D. Brown, CKM phase and CP Violation in B Decays
sin 2 in b s qq Penguins Sf= -sin 2 eff sin 2 1% CL for the average New naïve HFAG average <1 from the naïve golden mode sin 2 value 21 New/Updated Ba. Bar/Belle Result D. Brown, CKM phase and CP Violation in B Decays
Alpha l h l l 22 In principle measurable using any b u dominated B 0 f. CP Very rare decays! BF~10 -6 In practice, penguin modes have similar magnitude, different EW phase extracting is a challenge! D. Brown, CKM phase and CP Violation in B Decays
B 0 → + - : b u ud B 0 tags NB B = 383 M Nsig = 1139± 39 NB B = 535 M Nsig = 1464± 65 PRL 98, 211801 (2007) PRD 75 (2007) 012008 2. 1 tension in C 23 D. Brown, CKM phase and CP Violation in B Decays
Extracting from B 0 → + - l l l CPV well established Problem: extract from eff Solution: Isospin l Measure isospin-related modes l l Rates and C/ACP (if possible) Adds another discrete ambiguity! M. Gronau and D. London, Phys Rev. Lett. 65, 3381 (1990) 9 ° BR(B 0→ π0 π0) = (1. 47 ± 0. 25 ± 0. 12)× 10 -6 C(B 0 → π0 π0) = -0. 49 ± 0. 35 ± 0. 05 BR(B± → π± π0) = (5. 02 ± 0. 46 ± 0. 29)× 10 -6 hep-ex: 0707. 2798 A(B± → π± π0) = 0. 03 ± 0. 08 ± 0. 01 24 D. Brown, CKM phase and CP Violation in B Decays 97 ± °
B 0 → a 1+ : b u ud l First TDCPV analysis of a 1+ Large signal observed l significant background NB B = 383 M B 0 tags background B 0 → K 1+ B 0 Nsig = 608 ± 53 tags PRL. 97, 051802 (2006) MB (Ge. V/c 2) NB B = 535 M Nsig = 654 ± 70 PRL 98 181803 αeff = 78. 6°± 7. 3° l hep-ex/0706. 3279 25 MB (Ge. V/c 2) l use SU(3) to relate states l BF B 0 → K 1+ l BF and ACP in B 0 → a 1 - Next step: constrain D. Brown, CKM phase and CP Violation in B Decays
B 0 → 0 : b u ud l Vector+Vector final state l l Analyze helicity to separate CP admixture as in B 0 → D*+D*- Use Isospin triangle to constrain as in TDCPV in NB B = 535 M NB B = 383 M Nsig=729 ± 60 hep-ex/0705. 2157 t (ps) PRD 76, 011104(R) (2007) C = 0. 01 ± 0. 15 ± 0. 06 S = -0. 17 ± 0. 20 26 f. L = 0. 992 ± 0. 024 D. Brown, CKM phase and CP Violation in B Decays t (ps)
The critical side: B 0 → 0 NB B = 520 M NB B = 427 M Nsig = 85 ± 27 ± 17 Ba. Bar Preliminary Nsig=34± 16 MB Ge. V/c 2 M Ge. V/c 2 Lsig/ Lsum signal Preliminary BELLE-CONF-0747 hep-ex/0708. 1630 27 Preliminary First TDCPV analysis of 0! D. t Brown, (ps)CKM phase and CP Violation in B Decays
Constraining using b u ud B 0 → ( 0 Ba. Bar Preliminary @68%CL ° 28 D. Brown, CKM phase and CP Violation in B Decays
Gamma D 0 BK- B h 29 KD 0 B+, B- rate asymmetry (DCPV) is sensitive to The problem: How to distinguish EW phase from strong phase? Can also measure 2 + via TDCPV in B 0 D+ -, + D. Brown, CKM phase and CP Violation in B Decays
from B± D 0 K± l Three Answers l D 0 decays to 2 -body CP eigenstates (K+K-, + -, …) GLW l l D 0 decays to non-CP eigenstates (K+ -, K+ - 0, …) ADS l l Better match in rates (Cabbio suppression enhances interference) D 0 decays to 3 -body (K 0 S + -) GGSZ l l large + unknown asymmetry in B+, B- BFs Uses (~known) variation of resonance strong phase across Dalitz plot Requires detailed model of resonant substructure All methods have (varying) weakness due to unknown or under-constrained parameters Constrain by combining results from all methods GLW Gronau, London (1991), Gronau, Wyler (1990) ADS Atwood, Danietz, Soni (1997) GGSZ Giri, Grossman, Soffer, Zupan (2003) 30 D. Brown, CKM phase and CP Violation in B Decays
Combined constraint on = 88 ± 16 ° Includes a new preliminary result: B± D 0 K± GLW (Ba. Bar) ° 31 D. Brown, CKM phase and CP Violation in B Decays
The Unitarity Triangle: angles only 32 D. Brown, CKM phase and CP Violation in B Decays
The Unitarity Triangle: all constraints A consistent picture across a huge array of measurements 33 D. Brown, CKM phase and CP Violation in B Decays
Bs J/ ( s): b c cs l l l Same quark decay as B 0 charmonium K 0 Bs mixing goes as Vts ~ no CPV phase Hep-ph/0612167 as in Bd mixing SM prediction of s = 4. 2 ± 1. 4 X 10 -3 Simultaneous fit to s, s Consistent with SM 34 D. Brown, CKM phase and CP Violation in B Decays
Direct CPV in charmless B Decays K*0 3. 8 K+ 0 3. 0 K+ ~8 K+ 3. 0 Isospin analogs AK (B+ K 0 )=0. 009 ± 0. 025 AK (B+ K+ )=0. 050 ± 0. 025 AK (Bd)=− 0. 095 ± 0. 012 (WA) Effect from EW penguins? 35 D. Brown, CKM phase and CP Violation in B Decays
Direct CPV in Bs Decays AK (Bd)=-0. 086 ± 0. 023 ± 0. 009 3. 5 significance AK (Bs)=0. 39 ± 0. 15 ± 0. 08 2. 3 significance Comparing AK (Bd, Bs) Consistent with SM prediction ≈1. 0 H. J. Lipkin, Phys. Lett. B 621, 126 (2005) 36 D. Brown, CKM phase and CP Violation in B Decays
Conclusions l Standard Model CKM CPV is well established l l Confirmed by many analyses, several experiments Unitarity angle precision continues to improve Sin 2 is still statistics limited! l New, innovative techniques are still being developed l l CPV provides a unique window on the SM l l Data constrain the unsolved problems of flavor/ generation mixing, matter-anti-matter asymmetry The existing B-factories will soon be turned off Ba. Bar, Belle complete in ~2008, Tevatron in ~2009 l Look for final analyses in 2009 -2010! l l Future flavor physics depends on future facilities l LHCB, super-Belle, … 37 D. Brown, CKM phase and CP Violation in B Decays
BACKUP D. Brown, CKM phase and CP Violation in B Decays
The B-factories Belle KEK-B PEP-II 39 D. Brown, CKM phase and CP Violation in B Decays
Datasets Pep-II Ba. Bar 40 Total ≈ 450 fb-1 KEK-B BELLE Total = ≈ 700 fb-1 D. Brown, CKM phase and CP Violation in B Decays
B 0 → J/ 0: b → c cd NP particle can enter in loop l Enhanced sensitivity to higher-order (penguin) diagrams l Cross-check on assumption that Cgold≈0 M. Ciuchini, M. Pieriniand. L. Silvestrini, Phys. Rev. Lett 95, 221804(2005) C NB B = 535 M 290 J/ψπ0 candidates Purity=88± 7% S=− 0. 65 ± 0. 21± 0. 05 C= -0. 08 ± 0. 16 ± 0. 05 (0, 0) hep-ex/0708. 0304 (submitted to PRD. RC) MB (Ge. V/c 2) 41 D. Brown, CKM phase and CP Violation in B Decays S
B 0 → D*+- D-+ : b → c cd l Final state not a CP eigenstate Could show time-integrated charge asymmetry l TDCPA modified by strong phase difference (S+- ≠ S-+, C+- ≠ C-+) l l l If penguin contribution is zero, C-+ = -C+- , eff= If S-+= -S+- , No CPV sin(2 eff) = 0 42 D. Brown, CKM phase and CP Violation in B Decays
S and C in B 0 → D*+- D-+ : b → c cd B 0→D*+DNB B = 383 M 280 ± 19 signal events B 0→D*-D+ 219 ± 18 signal events Hep-ex/0705. 1190 Time-integrated asymmetry consistent with 0 sin(2 cosd 0 @ 4 No significant direct CPV 43 D. Brown, CKM phase and CP Violation in B Decays
B 0 → D 03 -bodyh 0 : b → c ud l l D 0→KS + - = coherent ensemble of quasi 2 -body decays (Known) variation of strong phase over Dalitz plot allows extraction of strong and weak phase differences! Must measure TDCPA at all points in the Dalitz plot l 2 -fold ambiguity on can (in principle) be resolved l NB B = 383 M Nsig = 335 ± 32 Ba. Bar Preliminary (update) hep-ex/? ? 44 D. Brown, CKM phase and CP Violation in B Decays
B 0 → D 03 -bodyh 0 Dalitz Analysis : b → c ud Ba. Bar Preliminary B 0 tagged h 0 = 0, ('), B 0 tagged K*- 0 Asymmetry K*+ cos 2 >0 at 84% CL 45 D. Brown, CKM phase and CP Violation in B Decays
B 0 → KSK+K- : b s qq l Measure TDCPA at each point on the Dalitz plot l Includes interference between K+K-, KSK± resonances hep-ex/0706. 3885 ACP = − 0. 015 ± 0. 077 ± 0. 053 eff = 0. 352 ± 0. 076 ± 0. 026 rad 46 D. Brown, CKM phase and CP Violation in B Decays 4. 8 significance
B 0 → D 0 CPh 0 : b → c ud NB B = 383 M Nsig =335± 32 background l l b → c ud tree dominates b → u cd suppressed ~1/50 D 0 CP D 0 → KK, KSw l also D*0 → D 0 CP h 0 w h SM predicts S=-sin 2 , C≈0 hep-ex/0703019 First TDCPA in these modes! 47 D. Brown, CKM phase and CP Violation in B Decays
B 0 → KSKS : b d ss EW decay phase cancels mixing K 0 phase No CPV Vtd expected! B 0 d K 0 R. Fleischer and S. Recksiegel, Eur. Phys. J. C 38: 251 -259, 2004 Raw Asymmetry C (0, 0) B 0 Nsignal=33± 6 tags B 0 tags background BELLE-CONF-0723 S = - 0. 38 0. 77 0. 08 C = +0. 38 0. 05 Ba. Bar result PRL 97 (2006) 171805 S 48 NB B = 657 M Entries/2. 5 ps SM expectation: S≈0, C≈0 A. K. Giri and R. Mohanta, JHEP, 11, 084(2004) D. Brown, CKM phase and CP Violation in B Decays
l l l Constraining in B → a 1 via SU(3) No phase-space overlap between a 1+, a 1 -, and a 10 Can use SU(3) to relate p K and a 1 K 1 A Gronau & Zupan, Phys. Rev. D 73, 057502 (2006) Necessary BFs are measured, not yet computed B 0 → a 1 - B 0 → K 1+ Ba. Bar Preliminary MK Ge. V/c 2 BF(B 0 K 1+(1270) -) = 12. 0 ± 3. 1 +9. 3 -4. 5 X 10 -6 BF(B 0 K 1+(1400) -) = 16. 7 ± 2. 6 +3. 5 -5. 0 X 10 -6 49 MB Ge. V/c 2 BF(B 0 a 1 - K+) • BF(a 1 - + - -) = 8. 2 ± 1. 5 ± 1. 2 X 10 -6 Ach(B 0 a 1 - K+)= -0. 16 ± 0. 12 ± 0. 01 BF(B+ a 1+ K 0) • BF(a 1+ + + -) =17. 4± 2. 5 ± 2. 2 X 10 -6 Ach(B+ a 1+ K 0) =0. 12± 0. 11 ± 0. 02 D. Brown, CKM phase and CP Violation in B Decays
B 0 → : b u ud l Can use Isospin as in + l New method: use (known) resonance phase variation over Dalitz to analyze EW phase l Eliminates some ambiguities Interference Region. Monte Carlo ρ+ π - ρ-π+ 0 B 0 0 π 50 ρ Monte Carlo B 0→ρ- π+ → B 0→ρ+ π- l ‘pentagon’ relationship -> more terms to measure ρ0 π 0 D. Brown, CKM phase and CP Violation in B Decays
B 0 → : b u ud N(B 0→π+ π- π0) = 2067 ± 86 Aρπ (ρ± π∓) = -0. 14 ± 0. 05 ± 0. 02 C (ρ± π∓) = 0. 15 ± 0. 09 ± 0. 05 S (ρ± π∓) = -0. 03 ± 0. 11 ± 0. 04 ΔC (ρ± π∓) = 0. 39 ± 0. 09 ΔS (ρ± π∓) = -0. 01 ± 0. 14 ± 0. 06 C 00 (ρ0 π0) = -0. 10 ± 0. 40 ± 0. 53 S 00 (ρ0 π0) = 0. 02 ± 0. 22 ± 0. 09 hep-ex/0703008 87° 74° 51 NB B = 383 M PRL 98, 221602 (2007) TDPA + isospin NB B = 449 M 132° D. Brown, CKM phase and CP Violation in B Decays TDPA only
GLW results 4 observables, 3 unknowns 52 CP-even: D K+K−, + − CP-odd: D KS 0, KSw, KS D. Brown, CKM phase and CP Violation in B Decays
ADS results 2 observables, 5 unknowns AADS =− 0. 22 ± 0. 61 ± 0. 17 53 D. Brown, CKM phase and CP Violation in B Decays
GGSZ Results Physical Variables r. B , δ B , γ Modes in DKK (*)K(*) 54 Gaussian Variables x+ = r. B cos( δ B+γ ), y+ = r. B sin( δ B+γ ) x− = r. B cos( δ B−γ ), y− = r. B sin( δ B−γ ) Similar for Y+, YD. Brown, CKM phase and CP Violation in B Decays
CPV in (4 S) Decay l If large, would invalidate sin 2 from TDCPA results Method: partial reconstruction Full reconstruction (4 S) B 0 NB B = 535 M + J/y +- K S J/y, hc Partial reconstruction Nsig = -1. 5 +3. 6 -2. 8 events Br( (4 S) B 0 B 0 J/ KS+J/ (hc)KS) < 4 x 10 7(90%C. L. ) SM expectation: ~1. 4 x 10 -7 55 D. Brown, CKM phase and CP Violation in B Decays ar. Xiv: 0707. 4336 (submitted to PRL) l
How this all started. . . In the early universe, for every billion ordinary particles annihilating with antimatter, one was left standing… • CKM CPV is too small to account for observed matter/anti-matter asymmetry by a factor of ~10 -20 • Due to ‘Heavy’ Higgs, 12 factors of lambda for simplest process resulting in matter/anti-matter asymmetry 56 D. Brown, CKM phase and CP Violation in B Decays
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