BaBar physics, recent highlights and future prospects Owen Long, BaBar physics analysis coordinator U. C. Riverside & SLAC December 5, 2008

BaBar physics, recent highlights and future prospects Page 2 Outline General overview Highlights from core CKM measurements and searches for New Physics in the Y(4S) data e + e -   +  - (  ) cross section from ISR Highlights from the 2008 data –Discovery of the  b –Search for a light Higgs –Precision scan of R b above the Y(4S) Looking forward

BaBar physics, recent highlights and future prospects Page 3 The BaBar physics program Perform the first precision tests of CP violation within the Standard Model. Over constrain the CKM quark mixing matrix parameters with measurements of CP asymmetries in B decays and semileptonic B decays. Search for signs of New Physics in rare B decays. Studies of open charm: mixing and CP violation in D decays, leptonic and semileptonic D decays. Tau lepton physics: tests of unversality, searches for lepton flavor violation, determination of |V us |. Continuum studies using initial state radiation (ISR) events. Quarkonium spectroscopy. b W s t 

BaBar physics, recent highlights and future prospects Page 4 BaBar datasets Totals up to Sept M 630 M 460 M Quick decision in Dec. 07 to run on Y(3S) and Y(2S). 120 M Y(3S) [20x Cleo] 100 M Y(2S) [12x Cleo] Data taking ended on April 7, 2008 Average efficiency 96% Peak luminosity 12 x cm -2 s -1 Average efficiency 96% Peak luminosity 12 x cm -2 s -1 About 4 times design value! BaBar

BaBar physics, recent highlights and future prospects Page 5 BaBar publications Total published papers PRL 165 PRD 188

BaBar physics, recent highlights and future prospects Page 6 Highlights of the CKM program and searches for New Physics Y(4S) analyses

BaBar physics, recent highlights and future prospects Page 7 sin2  from b  (cc)s One dominant decay amplitude No direct CPV expected Final analysis: 465 M BB stat.syst. Theoretical uncertainty in predictions ~1% Still statistics limited! Consistent with Belle measurement (CP odd) (CP even) arXiv:

BaBar physics, recent highlights and future prospects Page 8 sin2  from loop-dominated B decays All new measurements. All use full dataset: 465 M BB Expect S=sin2  in SM. Large deviations possible if NP in the loop. All consistent with SM but statistics limited. No significant direct CPV, as expected in SM.

BaBar physics, recent highlights and future prospects Page 9 Testing the CKM model BaBar and Belle have established the CKM matrix as the dominant source of CP violation. Kobayashi and Maskawa awarded 2008 Nobel prize in physics. Cabibbo Kobayashi Maskawa matrix u c t dsb

BaBar physics, recent highlights and future prospects Page 10 Search for New Physics in b  s  “Radiative penguin” b W s t  16 exclusive, self-flavor-tagging final states with 0.6 GeV < M Xs < 2.8 GeV Standard Model: A CP < 1% New Physics: A CP up to 15% Published: PRL, 101, (2008)

BaBar physics, recent highlights and future prospects Page 11 e + e -   +  - (  ) cross section from ISR

BaBar physics, recent highlights and future prospects Page 12 e + e -   +  - (  ) and the muon g-2 SM prediction: ( ± ± ± 0.2 ) x Uncertainty on direct measurment of a  is ± 6.3 x is the limiting factor in SM prediction. Measure dominant contribution to with  decays or  [e + e -  hadrons]. from  decay15.1 ± 9.3 (1.6  ) from e + e ± 8.4 (3.3  ) ~73% of a  had is  +   dominant uncertainty) 

BaBar physics, recent highlights and future prospects Page 13 e + e -   +  - (  ): experimental technique Use ISR process to scan e + e -   +  - (  ) cross section as a function of energy Measure the ratio of  (  )  ISR and  (  )  ISR cross sections to cancel many systematics. ISR

BaBar physics, recent highlights and future prospects Page 14 e + e -   +  - (  ): results and interpetation 0.6% measurement in rho region ( GeV)! Measurement agrees better with  results. (g-2)  discrepancy significantly reduced. Preliminary result shown by Michel Davier at tau’08

BaBar physics, recent highlights and future prospects Page 15 Highlights from data taken in 2008 Discovery of the  b Search for a light Higgs Precision scan of R b above the Y(4S)

BaBar physics, recent highlights and future prospects Page 16 The bottomonium spectrum Bottomonium (bb) first discovered ~30 years ago. Many states below the open beauty (BB) threshold yet to be discovered. Measurement of  b mass useful for testing lattice QCD and potential models. J PC

BaBar physics, recent highlights and future prospects Page 17 Y(nS)   b : analysis technique Inclusive search for Signal is a mono-chromatic photon peak. Two peaking backgrounds close to expected signal ~770 MeV ~855 MeV For M(  b ) = 9.4 GeV, E  = ~911 MeV

BaBar physics, recent highlights and future prospects Page 18 Y(3S)   b : discovery PRL 101, (2008)

BaBar physics, recent highlights and future prospects Page 19 Y(2S)   b : confirmation  (2S) spectrum  (3S) spectrum bb bb ISR  b (1P)  b (2P)  (2S) analysis:  (3S) analysis: Shown at QWG by Peter Kim

BaBar physics, recent highlights and future prospects Page 20 Search for a light Higgs: Y(3S)   A 0 Next-to-minimal SUSY adds a singlet Higgs field. Extra CP-odd Higgs state (A 0 ) can be light (m A < 2m b ) and dominantly decay into a pair of LSPs (invisible). Search for Y(3S)   A 0 : 2-body decay with a mono-chromatic photon recoiling against something undetected. Special single photon triggers added (E  * > 1 GeV and E  * > 2 GeV).

BaBar physics, recent highlights and future prospects Page 21 Light Higgs search: analysis results Sample fits showing a particular assumed A 0 mass. Fitted signal yield as a function of A 0 mass. High energy sample Low energy sample

BaBar physics, recent highlights and future prospects Page 22 Light Higgs search : analysis results Non-singlet fraction of the A 0 Scan of NMSSM parameters upper limit vs Higgs mass Higgs mass ranges for colored points in NMSSM parameter scan. arXiv: PRD 76, (2007)

BaBar physics, recent highlights and future prospects Page 23 Precision scan of R b above the Y(4S) Motivated by recently observed exotic cc states –Tetraquarks, molecular states, hybrid qqbar+gluon states, …? –The bb J PC = 1 -- states should be above the Y(4S), below 11.2 GeV. Collected 10 days of data in E cm from GeV to 11.2 GeV. –5 MeV steps (x4 finer than previous scans) –Integrated luminosity of 25 pb -1 / step (>x30 higher than previous scans) –Energy of positron beam fixed at 3.12 GeV, electron beam energy varied. –Previous scan was ~25 years ago.

BaBar physics, recent highlights and future prospects Page 24 Precision scan of R b above the Y(4S) Structures above 4S in region of threshold openings qualitatively match predictions of coupled channel model. Simple fit above 10.8 GeV gives substantial differences w.r.t. the PDG for the Y(10860) and Y(11020) (or “Y(5S)” and “Y(6S)”). Prediction of coupled channel model (circa 1984). PRL 53, 878 (1984) arXiv: , submitted to PRL

BaBar physics, recent highlights and future prospects Page 25 BaBar looking forward

BaBar physics, recent highlights and future prospects Page 26 BaBar plans IFC Intense Steady BaBel Archival Build up Writing Launch  150 New publications Final Editing Pier-review TaskForce BaBar Beyond 2010

BaBar physics, recent highlights and future prospects Page 27 Taskforce BaBar beyond

BaBar physics, recent highlights and future prospects Page Nobel Prize in physics “Please accept our deepest respect and gratitude for the B factory achievements. In particular, the high-precision measurement of CP violation and the determination of the mixing parameters are great accomplishments, without which we would not have been able to earn the prize.” - Makoto Kobayashi and Toshihide Maskawa