Babar risultati e prospettive Concezio Bozzi INFN Ferrara
Babar: risultati e prospettive Concezio Bozzi, INFN Ferrara - 18 Settembre 2006
Physics reach of Ba. Bar Data Just about any physics that is accessible at CP Studies with B’s & B Physics e+e- X Charm Physics Tau physics Continuum e+e- hadrons ISR: e+e- hadrons from threshold to ~5 Ge. V 2* m B
Luminosity Our competitors: 550/fb The challenge: • new ideas • more channels • more sophisticated analyses 354/fb
Babar @ ICHEP 06 Semileptonic B: 10 papers Radiative and leptonic B decays: 12 papers CP Violation, a: 5 papers Charmless Hadronic B: 19 papers Charm(onium) prod and decay 13 papers B to charm decays: 12 papers Tau and low-energy: 8 papers Charm(onium) spectroscopy: 16 papers CP Violation g: 8 papers CP Violation, b: 14 papers http: //www-public. slac. stanford. edu/babar/ICHEP 06_papers_temp. htm
ICHEP 2006 • 114 contributed papers! – 69 in 2005, 72 in 2004 – 70 submitted to journals – 44 conference papers Belle submitted 28 papers only • Two plenary talks • 24 parallel talks in 6 different sessions • All updates are on 345 fb-1 (315 onpeak) – Up to June 1 st
Paper luminosity Since Sep. 1 st 2005: Ba. Bar: 70 Belle 28
Non B physics (1/3) Semileptonic B: 10 papers Radiative and leptonic B decays: 12 papers CP Violation, a: 5 papers Charmless Hadronic B: 19 papers Charm(onium) prod and decay 13 papers B to charm decays: 12 papers Tau and low-energy: 8 papers Charm(onium) spectroscopy: 16 papers CP Violation g: 8 papers CP Violation, b: 14 papers Reviewed in http: //ichep 06. jinr. ru/reports/4_11 p 30_pakhlov. ppt
0 0 D -D mixing highly suppressed in SM- a powerful window for NP searches Observables: CP even state: width G 1 , mass m 1 ; CP odd state: width G 2 , mass m 2 y = (G 1 - G 2) / (G 1 + G 2) = DG / 2 G x = (m 1 – m 2) / G = Dm / G Belle has another “ 2 ” effect in D K Close to observation?
Charm spectroscopy Keep finding New Charm Meson and Baryon states! Wc * W c 0 New 2860 candidate in m(DK) 3 modes combined, bkg subtr. Resonance structure at ~2690? Properties of 2860? Spin 3? First observation of a new excited charm baryon Wc * W c 0 Last missing L=0 single charm baryon
FCNC in D decays Standard Model: BF(D Xul+l-) = O(10 -8) R-parity violating SUSY : BF(D Xul+l-) ≤ O(10 -5) BABAR uniquely measures all D->Xll’ modes. Most limits are better than previous results
Y(4260) new excitement Search for e+e- Y(4260)g. ISR Y Y(2 S) J/Y The b does road Y(4 26 not s how 0) up Hints of something close to the “second peak”
Initial State Radiation Hadrons • e+e- from threshold to ~5 Ge. V • Determination of R, goes into calculation of muon g-2. e+e pp, + 2 +2 K+K- + 2 K+2 K-, 3 +3 2 +2 K+K-2 +2 K+K + K+K f 0 New structure m~2. 175 Ge. V, G~60 -80 Me. V, JPC=1 -“Strange” partner of Y(4260) with cquark replaced by s-quark? ssss-state?
CKM Physics (1/3) Semileptonic B: 10 papers Radiative and leptonic B decays: 12 papers CP Violation, a: 5 papers Charmless Hadronic B: 19 papers Charm(onium) prod and decay 13 papers B to charm decays: 12 papers Tau and low-energy: 8 papers Charm(onium) spectroscopy: 16 papers CP Violation g: 8 papers CP Violation, b: 14 papers Reviewed in http: //ichep 06. jinr. ru/reports/2_hazumi_ichep 2006. ppt and 3_10 p 20_Kowalewski. pdf
UT Roadmap Charm(less) Semileptonic decays * |Vud. Vub| Loops (might be) involved New physics Interference between Time-dependent measurements mixing and decay a 2 * |Vcd. Vcb| g 3 Interference between Tree level processes b→u and b→c Time-independent SM only measurements * BB mixing, b→d /b→s |Vtd. Vtb| * |Vcd. Vcb| b 1
Bread and butter… Repeated standard set of measurements hep-ex/0607107 2. 5 s direct CPV in CP=-1 modes Belle has only updated J/YK 0 still without publication
Hunt for new physics sin 2 b with penguin-dominated modes How well do we know DSf within the SM? SM: Sf~ -hcpsin 2 b NP: Sf~ -hcpsin 2 b Measure DSf=-hcp. Sf – sin 2 b & search for deviation from zero sin 2 beff-sin 2 b
b s penguins Larger Ba. Bar errors because of full Dalitz (see next slide) Moving up towards SM Naïve average of all b g s modes sin 2 beff = 0. 52 ± 0. 05 2. 6 deviation between penguin and tree (b g s) (b g c) New result not yet in averages (more work needed) Ba. Bar still exploits luminosity significantly better than Belle Ba. Bar: 347 M BB Belle : 535 M BB
B K+K-K 0 First ambiguity free measurement of b in b s penguins hep-ex/0607112 • toy Dalitz plot 75% of B KKK 0 is not B Ks – Important to understand the underlying background and its interference • Full time-dependent Dalitz analysis performed – Knowledge of strong phase and interference between CP-even and CPodd components allows to extract weak phases without ambiguities • Assuming SM (i. e. same weak phase for all final states) – b=0. 38± 0. 08 rad [SM=0. 35] very good agreement with SM – ambiguity on b resolved at the 4 level (SM favored) Twice more sensitive than Belle in B Dh 0 K 0 f 0(980)K 0 X 0(1550)K 0 Nonreson ant D
B KSKS Old Result: No report from Belle First TD analysis in b d penguins
The (long) way to a Tree M. Gronau, D. London, Phys. Rev. Lett. 65, 3381 (1990) B-> r r sets the scale of the Da correction Penguin
It was unbelievably good… First evidence of B→ r r 0 0 m. ES 0 f 0 N 0 0 = 98+32 − 31 ± 22 3. 0 significance hep-ex/0607097 ΔΕ +0. 37 Br 0 0 = (1. 16 − 0. 36 ± 0. 27) 10− 6 Error on a from B→rr dominated by B→ r r limit: (a from 11 o to 18 o Belle: no news, never presented a result
2 -body update B 0 tags N 0 0 = 140 ± 25 0 0 _ B 0 tags asymmetry S = − 0. 53 ± 0. 14 ± 0. 02 C = − 0. 16 ± 0. 11 ± 0. 03 3. 6 evidence of CPV Br 0 0 = (1. 48 ± 0. 26 ± 0. 12) 10− 6 C 0 0 = − 0. 33 ± 0. 36 ± 0. 08 hep-ex/0607106
Comparison with Belle’s (C = A) 2. 3 diff. btw. Belle and Ba. Bar
Religious wars… Indirect meas. Direct measurements
g: no golden channel + B- (D f)KF=common to D 0 & anti D 0 Solve for , & d=(, d 1 -d 2) – r. B=(|A 1|/ |A 2|) f=DCP (Gronau-London-Wyler)(GLW method) (small asymmetry) f=DCSD (Atwood-Duniets-Soni)(ADS Method) (additional problem of d. D) f= Dalitz analysis of D 0 ->Ksp+p- (GGSZ) (combines features of GLW & ADS depending on the location in Dalitz plot)- the dominant method [Giri, Grossman, Soffer, & Zupan, PRD 68, 054018 (2003), Bondar (Belle), PRD 70, 072003 (2004)]
Interference gets smaller! Dalitz analysis update hep-ex/0607104 Errors shrink (in particular systematics), but r. B is smaller error on g increases … (was 70± 31 ± 1210± 1411 ) No update from Belle
BABAR + Belle constraints on g from direct measurements From the Dalitz Analysis alone: Error due to uncertainties in treatment of the (Ba. Bar) D Ks -Dalitz plot (amplitudes and phases) g=(92+/- 41 11 +/- 12 φ3=53° +15 -18 3° 9°) Belle )o -CLEO-c data can help. Projected error 3 -5 deg (@1/ab The method highly sensitive to r. B: fits favor r. B ~ 0. 1 (Ba. Bar) ; r. B >0. 2 (Belle). Main cause of the difference in errors • Error on g depends crucially on value of r. B • Combined direct constraint: g= (78 +/- 30)o
|Vub| measurements Exclusive Inclusive Tagged Untagged
b ul exclusive: probing theory New “loose cuts method” Old technique, 80 fb-1 4 more results on Vub and 2 on Vcb
Inclusive channels Exclusive channels ~7% measurement now Aiming for 5% accuracy Must resolve exclusive & inclusive discrepancy
“There is a tension…” …really?
Prospects in the “ 1/ab” phase (~ +1/ab from Ble) Aiming for: Now ~7% ~30° ~18° ~0. 04 Also counting on improved systematics in most areas & help from theory side r. B=0. 1
Other B decays (1/3) Semileptonic B: 10 papers Radiative and leptonic B decays: 12 papers CP Violation, a: 5 papers Charmless Hadronic B: 19 papers Charm(onium) prod and decay 13 papers B to charm decays: 12 papers Tau and low-energy: 8 papers Charm(onium) spectroscopy: 16 papers CP Violation g: 8 papers CP Violation, b: 14 papers Reviewed in http: //ichep 06. jinr. ru/reports/5_12 p 10_Barlow. ppt
B→ : easy to interpret New BABAR result: 320 M BB events, Tagged with B DXln decays EMiss Data New physics: Replace W+ by H+? BF(B+ + )= (0. 88 +0. 68 0. 11) x 10 -4 -0. 67 EMiss Signal MC BR< 1. 80 10 -4 @ 90%CL • Sensitivity nearly at SM expectation • Additional hadronic B decay tagged sample hep-ex/0608019
B : a year of emotions • April: Belle announces at FPCP a >4 evidence for B • May-July: Ba. Bar struggles to reproduce the accuracy of Belle (in an area where we were traditionally more advanced) • August: – Ba. Bar presents only one of the two independent analyses while still investigating – Belle presents an errata of the efficiencies by a factor 2!!!! • Significance down to 3. 5 , BF a factor 2 larger • Ba. Bar and Belle have similar accuracies • Soon: Ba. Bar is ready to publish both analyses expect an error which is 40% smaller than Belle’s BF(B+ + )
Impact on new physics PRD 48, Limits on e. g. 2 Higgs doublet model W. S. Hou, 2342 (1993) SM prediction enhanced/reduced by factor r. H Or: Within the SM, use the value of BF(B+ + ) to give a measurement of f. B
Radiative B decays FCNC process suppressed in SM: sensitive to new particles in loops b s : Inclusive and many exclusive measurements b sl+l-: More information from kinematics b d : strongly suppressed but open to different physics b d l+l -: on the way
Observation of b dg decays: B rg B+ + B 0 0 • First observation of B r+g 4. 1 • Good agreement with predictions based on Standard Model amplitudes hep-ex/0607099 No update from Belle
FCNC: B K(*)ll • Rarest B decays yet observed • New analysis adds measurements of decay kinematics B Kll (46 events) B K*ll (57 events) PRD 73, 092001 (2006)
Forward-backward asymmetry Experimental results Theoretical curves • Theoretical uncertainty on kinematics generally smaller than on branching fraction • Beyond SM particles in loops may have dramatic effect on short distance physics – flip sign of AFB?
Summary Ba. Bar is entering in its “ 1/ab” phase. Expected major outcomes are: Ø Precision knowledge of the flavor sector of the SM Ø Measurements of CP violation and decay properties in penguin-dominated decay modes Ø Measurements of rare decays in charm and tau physics With the possiblity to reveal deviations from the SM [If we continue to see no deviation at these precisions- the results will likely serve as major constraints on the flavor structure of New Physics- to be seen at LHC. ]
“See your tax dollars at work!” http: //www-public. slac. stanford. edu/babar/ICHEP 06_papers_temp. htm • At ICHEP’ 06 Ba. Bar has achieved record productivity, overwhelming the direct competitor • In the topics where the luminosity matters the refined statistical analysis technique makes Ba. Bar competitive even with 35% less luminosity (345 M BB/547 M BB) • Showed dominance in several areas such as: – CPV in b s penguins • New modes – Measurements related to a • First observation of B r r – Dalitz Time Dependent analyses • First full analysis of B KKK 0 (including K 0) – D-mixing in multibody D decays • Innovative technique to exploit also these decay modes – Leptonic B Decays • After Belle corrected a mistake in their efficiencies, we have a measurement of BF(B ) with same accuracy as them and potentially 40% better by fall – semileptonic B decays, Charm and Charmonium spectroscopy, …
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