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Comprehensive Report on BABAR Project in Particle Physics Field with Detailed Analyses

This report provides insights into the BABAR project, detailing the data collected, detector specifications, analyses, and measurements related to CP violation and meson reconstruction in particle physics research.

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Comprehensive Report on BABAR Project in Particle Physics Field with Detailed Analyses

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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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