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B A B AR : ACTIVITY REPORT

B A B AR : ACTIVITY REPORT. @. G. Finocchiaro on behalf of the LNF-BABAR group: F. Anulli, R. Baldini, A. Calcaterra, R. de Sangro, G.F., S. Pacetti, P. Patteri, I. Peruzzi (PI), M. Piccolo, M. Rama, A. Zallo. Final collisions 12:43pm, Monday 7 Apr 2008. Final data sample.

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B A B AR : ACTIVITY REPORT

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  1. BABAR: ACTIVITY REPORT @ G. Finocchiaro on behalf of the LNF-BABAR group: F. Anulli, R. Baldini, A. Calcaterra, R. de Sangro, G.F., S. Pacetti, P. Patteri, I. Peruzzi (PI), M. Piccolo, M. Rama, A. Zallo

  2. Final collisions 12:43pm, Monday 7 Apr 2008 ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  3. Final data sample Total data collected until September 2007: • 470M BB pairs, • 630M cc events, • 440M t Run 7 (Dec 07- Apr 08), collected: • 30/fb at Y(3S) [100M Y(3S)] • [6M from CLEO, 11M from Belle] • searches, lepton universality • detailed bottomonium spectroscopy • 14/fb at Y(2S) (140M Y(2S)] • [9M from CLEO] • Scan above the 4S • exotic bottomonium? ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  4. BABAR ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  5. The BABAR detector ElectroMagnetic Calorimeter 6580 CsI crystals e+ ID, π0 and γ reco Čerenkov Detector 144 quartz bars K, π, p separation Drift CHamber 40 layers tracking + dE/dx Silicon Vertex Tracker 5 layers (double-sided Si sensors) vertexing + tracking (+ dE/dx) Instrumented Flux Return 12-18 layers of RPC/LST μ, KL ID ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  6. Instrumented Flux Return (IFR) • Absorber-detector alternating layers for  and KL detection: • Bwd endcap: original RPC (18 layers); • Fwd endcap: new RPC (16 layers) in streamer or avalanche mode; • Barrel: old degraded RPC replaced by LST in summer 2004/2006 (12 layers) -ID performance • Italy + US teams • Detectors and read-out built in Italy (both RPC and LST) • System Managers: 1 Italy + 1 US for each subsystem; • Operation Managers: 2/3 Italy + 1/3 US ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  7. Analyses discussed in this talk • Latest update of sin2b in b→ccs • Latest measurement of g • B0→ D*+Ds*- • B0→ D*+D*- time-dependent • e+e-→KKp, KKh with ISR ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  8. Analyses discussed in this talk • Latest update of sin2b in b→ccs • Latest measurement of g • B0→ D*+Ds*- • B0→ D*+D*- time-dependent • e+e-→KKp, KKh with ISR ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  9. Independent of phase convention amplitude ratio q/p mixing mixing Preamble: time-dependentmeasurements at the B factories (I) CPV can arise from interference between two paths, e.g. decay with and without mixing Time-dependent (TD) CP asymmetry: ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  10. Quick recipe for TD measurements at B-factories • reconstruct final (CP eigen)state • determine (‘tag’) B0 flavor at decay time • measure decay vertices • fit… Coherent B meson production (L=1) Exclusive B meson reconstruction B-Flavor Tagging bg≈0.55 ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  11. J/y B0 B0 K0 • Flagship B-factory measurement • background-free • Latest sin2b update from BABAR (383M BB), featuring: • Detailed study of CP properties of background • reduced systematics • Updated hcKS selection • Independent measurements for each charmonium mode • Add J/yKL and J/yK* samples (larger backgrounds) to measure |l| sin2b from b→ccs a g b ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  12. DE IFR mm DE IFR ee DE EMC ee DE EMC mm pT(miss): missing measured-expected transverse momentum in the event projected along the KL direction • J/y KL second most abundant CP sample • Theoretically clean • KLdetection • 1 ≤ p ≤3 GeV/c • no signal in DCH • interaction onEMCorIFR • IFR `Neutral Hadron’ • measure direction with Dq~40/60mrad [control sample: fg→KsKLg (ISR)] • energy not measured • close kinematics with m2B0=(pJ/y+pKL)2 • use DE=|E*J/y+E*KL|-E*beam • sizeable background: fit more difficult than J/yKs • relative fractions from fit to DE ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  13. Ntag= 1056 P = 66% Ntag= 4748 P = 55% Ntag= 6873 P = 92% sin2b from B0 → charmonium + K0S,L 383M BB, PRL 99 171803 (2007) • Measure sin2b and |l| in 7 different modes (cc) K0S (CP odd modes) (cc) K0L (CP even mode) CP admixture ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  14. Flavor eigenstate sample used to determine tagging and vertexing performance in CP sample D(*)h+ (h+ = p+ , r+ ,a1+ ) J/yK*0 (K*0→ K+p-) Ntag= 123893 P = 85% sin2b from B0 → charmonium + K0S,L : fully reconstructed B flavor eigenstate channels • Simultaneous fit to incorporate statistical uncertainty of tagging and vertexing parameters into the sin2b statistical error ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  15. sin2b from B0 → charmonium + K0S,L : tagging algorithm performance • 6 mutually exclusive categories • category 1, ‘lepton’: primary leptons • categories 2-6 split based on estimated mistag rates (from neural net) • e≡ efficiency,w≡ mistag fraction, Dw≡ mistag fraction difference • Measure of tagging performance isQ = e(1-2w)2 ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  16. sin2b from B0 → charmonium + K0S,L : results sin2b =0.714±0.032±0.018 |l|=0.952±0.022±0.017 ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  17. New sin2b from charmonium decays ( ): comparison with other results • Experimental measurement sin2b[WA]=0.680±0.025 as precise as ‘indirect’measurement sin2b[UTFit]=0.690±0.023 • improving the experimental precision has still direct impact on UT fits • reference for loop-sensitive decay channels • Update on full dataset (470M BB) expected this summer ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  18. Analyses discussed in this talk • Latest update of sin2b in b→ccs • Latest measurement of g • B0→ D*+Ds*- • B0→ D*+D*- time-dependent • e+e-→KKp, KKh with ISR ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  19. b→ucs b→cus Measurement of g a g b • The phase of Vub • From direct CPV in the decay of charged B’s • Interfering tree amplitudes w/ CP-violating relative weak phase g and CP-conserving relative strong phase d • theoretically clean (i.e., no penguins involved) • Interference if D0/D 0 decay into identical final state • Dalitz plot (DP) analysis of 3-body decays, e.g., D0→Kspp • CP-eigenstate decay: Gronau-London-Wyler (GLW) • Doubly-Cabibbo-suppressed (DCS) decay: Atwood-Dunietz-Soni (ADS) ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  20. D 0 D0 +rBei(-g+dB) A(B-)=|A(B→D0K-)|× Dalitz Plot analysis of B→DK • The idea in pictures: • CP-conjugate B- and B+ decay amplitudes • B± Dalitz Plot distribution depends on , rb and . It is convenient to write the Likelihood as a function of the cartesian coordinates x± and y± • Likelihood is Gaussian and unbiased D0→Kspp m±2=m(KS±)2 Assume D decays conserve CP… ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  21. 383M BB Latest g measurement a g b • Newfeatures: • Added D0→KSKK (first time) • Improved D0 →KS pp Dalitz model • Added B→D0K* (D0 →KS pp only) • Increased reconstruction efficiency ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  22. 487k Evts purity:97.7% D0 → Ksp+p- 69k Evts purity:99.3% D0 → KsK+K- DP analysis of D0/D0 decays arXiv:0804.2089 subm. to PRD • Extract D0(bar) decay amplitudes from DP analysis of independent high-statistics cc sample with flavor-tagged D0→KS p+p- and D0→KS K+K- decays from D*+→D0 p+ • For D→Kspp we use theK-matrix model: 9 BW resonances + K-matrix formalism for  S-wave • Deals with broad, overlapping, multi-channel scalar resonances ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  23. Selection of signal • Select B±→ D(*)0K±, D*0→D0p0/g and B±→ D0K*±, K*±→Ksp±, with D0→Kspp/KsKK • mES, DE and Fisher are used in a max. likelihood fit to discriminate between signal and background • Control samples B→D(*)p and B→Da1 are also reconstructed to determine the shape parameters 386 106 BB B → DK, D→Kspp B→DK, D→KSKK Nsig: 610±34 Nsig: 132±14 ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  24. B→D0K* CPV 1.5s B→D0*K CPV 2.5s B→D0K CPV 2.2s Results arXiv:0804.2089 subm. to PRD Distance between (B+B-) points is 2rb|sin 2g| combined CPV: 3.0s extract CL for g, rb and db from x±,y± with frequentist stat. procedure includes exp. (5O) and Dalitz (5O) errors ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  25. 386 106 BB 657 106 BB Comparison with Belle Despite BABAR errors on x,y are better than Belle, error on g is worse: the “1/rb effect” ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  26. g summary From the BABAR physics book, 1999 • In fact, we can measure g! • g = (80±13)O • (Winter 2008 WA) • Together with Vub, defines • New Physics-free region(s) • in the r-h plane which any • NP model must take into • account ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  27. Analyses discussed in this talk • Latest update of sin2b in b→ccs • Latest measurement of g • B0→ D*+Ds*- • B0→ D*+D*- time-dependent • e+e-→KKp, KKh with ISR ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  28. Measurement of BF(B0 Ds+*D*-) and BF(Ds+ fp+) • B(Ds+→f p+)is necessary to normalize all DS branching fractions • consequently, all B Ds+X branching fractions as well • absolute charm branching fractions are difficult to measure because in general • backgrounds are sizeable • normalization (number of produced D’s) is unknown • both difficulties circumvented by BABAR’s measurement using partial reconstruction: • x2 improvement in BF accuracy ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  29. D 0 p- • D*+→D0p+ ; D0 to K-p+, K-p+p0, K-p+ p+p-, Ksp+p- • Do not reconstruct Ds+from Ds*+→ Ds+g: combineD* and g, and • calculate (EB=Ebeam) • f(BDs*) unmeasured • fixed arbitrarily (=0): no bias, small additional spread • calculate D*- B0 DS*+ g (DS+) all the rest NDs=7488±348 g from Ds*+ x3 improvement on WA Test of factorization at ‘high’ q2 Soft photon selection: p0veto;Energy and shower shape cuts ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  30. Exclusive reconstruction of Ds+→ fp+ • Measure from ratio • Most systematic uncertainties cancel out • x2 error improvement  benefit on all channels with DS NDs→fp=247±19 ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  31. Analyses discussed in this talk • Latest update of sin2b in b→ccs • Latest measurement of g • B0→ D*+Ds*- • B0→ D*+D*- time-dependent • e+e-→KKp, KKh with ISR ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  32. D(*)+ D(*)+ u,c,t D(*)+ D(*)- D(*)- D(*)- • Not a tree-level-only decay • |S+sin2b|teor.= 0.020.05 (factorization) • s(SD*D*)exp.= 0.19 (BABAR, exclusive reconstruction, statistics-dominated) • Partial reco: eExcl. reco x5 • aiming at comparable error as exclusive reco • samples almost statistically independent D* selection P(vtx)>1%;Dmlo <mD*-mD0 < Dmhi, with Dm{lo,hi} depending on D0 decay mode and nHIT(DCH) of psoft; |mD0-mpeak| < 3smD0; flight length and mKsper Ksp+p-; best D* from c2(Dm,mD0) and expected purity ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  33. Kaon tags Lepton tags BB bkg. BB bkg. qq bkg. qq bkg. D*+ + p-soft recoil mass(470M BB pairs) • Fractions of components determined on data from mmiss fit • B0 →D*+D*- is VV decay • not a CP eigenstate • ACP diluted by (1-2RT) RT= CP-odd fraction • ad-hoc tagging algorithm: exclude tracks from unreconstructed D0 ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  34. (blind) B0/B0bar Dt distributions for Kaon tags 383M BB Expect to publish by 2008 on full data set (Run 1-6) ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  35. Analyses discussed in this talk • Latest update of sin2b in b→ccs • Latest measurement of g • B0→ D*+Ds*- • B0→ D*+D*- time-dependent • e+e-→6p, KKp, KKh with ISR ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  36. Initial State Radiation • ISR processes at the (4S) can yield the same observables as low energy e+e-experiments, allowing for: • Precise measurements of hadronic cross section • JPC=1-- hadron spectroscopy for 1 < s < 5 GeV • Form Factor measurements • Discovery potential for new states [e.g. Y(4260), X(2175)] • Advantages: • All q at the same time  reduced uncertainties • CM boost • e≠0 at threshold • s(E) is O(few MeV) • Disadvantages: • L ~ DS bin width • More backgrounds ISR luminosity 0.35<qg(rad)<2.40 ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  37. Motivation: Hadron spectroscopy PRD73: 052003,2006 ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  38. Cross section measurement from production threshold to ~4.6 GeV for: • e+e- →K+K p0 • e+e- →KSK p+ • e+e- →fp0 OZI suppressed, never measured before, search for isovectorexotic states • e+e- →fhsearch for f(I=0) recurrences • e+e- →K+K h • Measured cross sections contribute to R in the corresponding energy range • Measurement of the J/y decay rates in all observed final states Mainly throughe+e-→KK*→KKpDalitz plot analysis to disentangle the different isospin contributions to the cross section and the relative phase Measurement of the KKp and KKh cross sections with ISR arXiv:0710.4451 [hep-ex] Accepted by PRD ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  39. e+e- →KS K±p∓ cross section • 3734 signal evts, purity 97% • Only stat. errors in figure • Syst. errors ~5% • B(J/y→KSKp) = (3.20 ± 0.23 ± 0.18)x10-3 Good agreement w/ old data much higher precision ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  40. e+e- →K+K-p0 cross section • 1378 signal evts, puprity 90% • Only stat. errors in figure • Syst. errors ~6.5% • B(J/y→KKp0) = (1.97 ± 0.16 ± 0.13)x10-3 Good agreement with old data much higher precision ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  41. K+K-p0 1524 evts KS K±p∓ 3860 evts Dalitz plot analysis of e+e- →K K p • Main process: e+e- → VP • Two isospin components: • FK*± K∓ (s) = F0(s) - F1(s) • FK*0 KS(s) = F0(s) + F1(s) K2*(1430) K*(890) Symmetric Dalitz no isospin separation |F0-F1| Asymmetric Dalitz  isospin separation |F0|, |F1| and relative phase ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  42. e+e-→K*(892)K→KS K±p∓: isospin analysis • K*(892)K dominant for Ecm<2GeV • I=0 component has clear evidence of f(1680) → K*(892)K • Resonant isovector component [r(1500)?] favored by relative phase • green bandwould correspond to non-resonant I=1 component ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  43. e+e- →fp0→K+K-p0 • fp0 is OZI-suppressed • pure isovector  r-like contributions • Broad structure (r) at ~1.6GeV • Sharp peak at Ecm~1.9 GeV compatible with the “dip” seen in multi-hadronic final states • adding a “r(1900)” the fit quality improves slightly ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  44. Non resonant KK First measurement of B(J/y→K+K-h) = (8.7±1.3±0.7) 10-4 f→K+K- 492 evts, purity 98% fit with `X(2175)’ and `f(1680)’ First observation of f(1680) → fh decay The parameters of f are compatible with the ff0(980) state already observed by BABAR [X(2175)] e+e- →K+K-h ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  45. Global fit of e+e- →KKp / KKh Global fit using all available information (KK*,K+K-p0, fh, fp0) to extract the parameters of observed states (f, f, r, r, r(1900)) ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

  46. 50 ab-1, NP 50 ab-1, SM Now Summary and outlook • BABAR data taking is now concluded • the SM survived all challenges so far • More, improved measurements using final data set • data with the “final reprocessing” will feature the best of the best in reconstruction, PID, analysis algorithms • Next step could be SuperB • group is responsible for the SuperB Drift Chamber upgrade ― G. Finocchiaro - LNFSC36 - 21 May 2008 ―

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