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Charm Physics at Super B Factories after BESIII, Belle and B A B AR

Charm Physics at Super B Factories after BESIII, Belle and B A B AR. David Hitlin The Future of Heavy Flavor Physics ITEP, Moscow July 24, 2006. Charm Physics - What is to be done ?.

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Charm Physics at Super B Factories after BESIII, Belle and B A B AR

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  1. Charm Physics at Super B Factories after BESIII, Belle and BABAR David Hitlin The Future of Heavy Flavor Physics ITEP, Moscow July 24, 2006

  2. Charm Physics - What is to be done? The current state of the art in charm physics is CLEO-c , which will compile ~.75/fb per physics objective BESIII will extend the data sample to ~20/fb It is beyond a cliché to point out that a B Factory is also a t/charm or Flavor Factory Thus a Super B Factory is also a Supert /charm or Super Flavor Factory BABAR and Belle have already produced many very interesting results in charm physics A Super B Factory can increase the data by 50 to 100 There is a strong motivation to do so for B decay studies CP asymmetries, BR, and kinematic distributions in rare B decays, primarily those involving Is there a similar motivation to do so for charm (or ) studies? David HitlinITEP Meeting July 24, 2006

  3. The question then naturally arises as to whether the t and charm data that a Super B factory would acquire in the 10 GeV region is sufficient, or whether it is interesting to take data in the 3.77 - 5 GeV region as well? • That is, are there specific physics topics that substantially benefit from threshold kinematics? • Are these objectives important enough to warrant the expense and running time taken from high energy running? • If there are such topics, what is the impact the designof a Super B Factory to allow it to run at lower CM energies? • In this context, a small group of SuperB adherents, most with t/charm experience, has been looking into this question John Back, Jose Bernabéu, Marcello Giorgi, David Hitlin, Antimo Palano, Frank Porter, Patrick Roudeau David HitlinITEP Meeting July 24, 2006 3

  4. Impact on SuperB design of low energy capability • Conventionally, for an e+e- collider:for a given tune shift, if below the RF power limit Use of wigglers is required to increase emittance, raise luminosity • The low emittance SuperB design under study for Tor Vergata has a different tune shift limit behavior and may therefore have a different energy dependence for the luminosity • Cost of low energy capability • Extra wigglers (?) • Running time lost to B physics • Savings on power David HitlinITEP Meeting July 24, 2006 4

  5. Working assumptions • CLEO-c: .75 fb-1 at (3770) and .75 fb-1 at (4170) by 2008 • BESIII: 20 fb-1 at (3770) and 12 fb-1 at (4170) (8 years) (BEPCII does not have enough energy to produce charmed baryons) • BABAR+Belle: 2 ab-1 total in ~2009 • SuperB at (and below) Ecm=10.58: L=1036: 1 year: 15 ab-1 5 years: 75 ab-1 in 4 GeV region: L~few x 1035: 1 month/year: 150-200 fb-1/topic We use an updated Snowmass Year: 1.5x107 sec (was 107 sec), based on PEP-II/BABAR and KEK-B/Belle experience (trickle injection, highly reliable detectors) David HitlinITEP Meeting July 24, 2006 5

  6. If low energy running proves desirable • It is unlikely that a Super B Factory would spend a large period of time running at low energies • A potentially realistic running strategy: • Assume a Super B Factory runs 10 months/year • 9 months with L=1036 at the (4S), producing =13.5/ab • 1 month (includes tuneup) in the 3.77-5 GeV region, at L=1.3 to 2.2 x 1035, producing ~120 to ~200/fb in each run, with the running time divided between: (3770), (4040), (4160), (4XXX), charmed baryons,running at 4.24 ……. David HitlinITEP Meeting July 24, 2006 6

  7. Super B Factory sample sizes David HitlinITEP Meeting July 24, 2006 7

  8. Charm production cross section ECM (GeV) ECM (GeV) David HitlinITEP Meeting July 24, 2006 8

  9. Charmed hadron production at B Factories? • Cross sections are large • Can use “off peak” data • Very high statistics (~1.4 x 106D’s / fb-1). Also: • Continuum production above and below 4S. • B decays – allow measurement of absolute B’s, and, perhaps, spins ? • D tagging - ~107 reconstructed D’s. • Can study charm baryons • ISR events • , - events On Off ECM (GeV) David HitlinITEP Meeting July 24, 2006 9

  10. Charmed mesons Absolute branching fractions CKM physics Dalitz plots Rare decays DD mixing CP violation Charmed baryons Lc Absolute Branching Fractions Form factors Precision R scan Charmonia Study of J/ , ’, ccj Y(4260), (4160), (4040) Search for charmonium hybrids Charm physics opportunities Which topics are better addressed at Ecm~4 GeV, and which at ~10 GeV ? David HitlinITEP Meeting July 24, 2006 10

  11. QCD tests + as Non-strange spectral function (much better resolution!) Strange spectral function (real measurement, v/a, … ) Second class currents Chiral perturbation theory Exclusive decays Branching ratios Light meson spectroscopy Michel parameters t lifetime – universality tests Vus from inclusive decays CP violation in t production and decay Rare decays LFV Neutral current couplings nt mass t physics opportunities Which topics are better addressed at Ecm~4 GeV, and which at ~10 GeV ? David HitlinITEP Meeting July 24, 2006

  12. Methodology • A first order comparison of measurement capability can be made by scaling from existing data sets • For example, for rare decays with little or no anticipated background, scaling is done as • When background is expected, scale by • Systematic limits must also be considered • With high statistics, can trade statistics for reduced systematic errors, but this is difficult to estimate with any degree of precision • In some rare decay cases, naïve scaling by sample size may favor high energy, but background may be better at the (3770) • Near threshold, use of mES improves resolution over minv, improving background rejection David HitlinITEP Meeting July 24, 2006 12

  13. Exclusive production at the (3770) • Exclusive DD with ED = Ebeam • s (DD) = 6.4 nb • Low multiplicity ~ 5-6 charged particles/event • High tagging efficiency: ~22% ,(~0.1%at the (4S)) 100 pb-1 @(3770) yields the same number of fully reconstructed events as 500 fb-1 @ (4S) CLEO-c Absolutely normalized hadronic, leptonic and semileptonic decays David HitlinITEP Meeting July 24, 2006 13

  14. Rare Charm Decays – FCNC and LFV Due to the large mass difference between up type quarks, the GIM mechanism suppresses short distance FCNCmore for up type quarks than for down type quarks Leptonic SM: The lepton flavor-violating mode is strictly forbidden. New Physics may enhance FCNC and LFV,e.g., R parity violating SUSY: Best limits are from BABAR Burdman et al. David HitlinITEP Meeting July 24, 2006 14

  15. Leptonic decays • Calibration of lattice QCD, search for FCNC Process CLEO-c BESIII SuperB @ 4GeV BABAR+Belle SuperB SuperB 1 month final 1 year 5 years 0.6%(e-6,e-7) 0.6%0.6% e-8e-8e-8 What does precision of lattice QCD calculation require of experiment? David HitlinITEP Meeting July 24, 2006 15

  16. Charm decays via FCNC Semileptonic heavily GIM suppressed: BF(cull)~10-8 New physics can introduce new particles into the loop: Some New Physics models increase B(cull) to 10-6—10-5 Potentially measurable! David HitlinITEP Meeting July 24, 2006 16

  17. Charm FCNC Branching Fraction Limits (preliminary) P. Jackson, Charm 2006 Upper limits on BF (x10-6) at 90% CL L (fb-1) BF Limits BABAR 250 1-3 x 10-5 SuperB 50000 6 – 18 x 10-7 David HitlinITEP Meeting July 24, 2006

  18. D0 Dalitz plot examples CLEO II.V: D. Cronin-Hennessey et al.PR D72 031102 (2005) John Back David HitlinITEP Meeting July 24, 2006

  19. CLEO II.V: D. Cronin-Hennessey et al.PR D70 091101 (2004) David HitlinITEP Meeting July 24, 2006 19

  20. CLEO II.V Comparison of Dalitz plots for 250/pb 91.5/fb David HitlinITEP Meeting July 24, 2006 20

  21. D branching fractions BABAR or Belle BABAR+Belle final SuperB 1 year SuperB 5 years Frank Porter David HitlinITEP Meeting July 24, 2006

  22. D branching ratios Statistical errors only Normalization relative to decays whose absolute BR’s can be measured at low energy Frank Porter David HitlinITEP Meeting July 24, 2006

  23. D0 mixing, CP violation n.b. extrapolations include statistical errors only Frank Porter David HitlinITEP Meeting July 24, 2006

  24. mixing • Achieving sensitivity at the 10-3 level requires distinguishing wrong sign decays due to mixing from DCSD decays • Rate of wrong sign decays • Measurement of time dependence is crucial (10GeV) • However, need to know d • At the (3770) can use quantum correlations between fully reconstructed D decays to determine d • At 10 GeV can determine d by measuring related DCSD modes (requires K0 modes) David HitlinITEP Meeting July 24, 2006 24

  25. Process CLEO-c BESIII SuperB @ 4GeV BABAR+Belle SuperB SuperB 1 month final 1 year 5 years 0.15% 0.06% 0.01% mixing comparison Statistical errors only David Asner David HitlinITEP Meeting July 24, 2006 25

  26. JP=1/2+ (L=0) JP=3/2+(L=0) Charm Isospin Strangeness JP=1/2+ (L=0) Charmed baryon states • |C| = 1: • L=0 Ground State – almost full: JP=1/2+: {6}qqSc(2455), Xc(2470), Wc(2698) All seen JP=1/2+: {3}qqLc(2285), X0c(2575) All seen JP=3/2+: {6}qqSc(2520), Xc(2645), ?? All but Wc* • L>1 – filling up ? JP=1/2-:Lc(2593), Xc(2790), … JP=3/2-:Lc(2625), Xc(2815), … • Several more new states from BABAR and Belle … and more No JP have yet been measured … from CLEO II (or )c(2880), (or )c (2765) ?? David HitlinITEP Meeting July 24, 2006 26

  27. 287fb-1hep-ex/0603052 First Charm Baryon  Charm MesonLc(2940) • Observed in cc continuum production inD0pdecay mode(D0 K-p+, K-p+p-p+) Λc(2940)+ : M = (2939.8±1.3±1.0) MeV/c2 Γ = (17.5±5.2±5.9) MeV Λc(2880)+ Λc(2940)+ New data on Λc(2880)+ : New Decay Mode D0p BABAR: M = (2881.9±0.1±0.5) MeV/c2 Γ = (5.8±1.5±1.1) MeV PDG: (“Could be Sc”) M = (2880.9±2.3) MeV/c2 ; Γ < 8 MeV Wrong sign D0p D0 mass sidebands David HitlinITEP Meeting July 24, 2006 27

  28. Charmonium hybrids • Charmonium hybrids are expected to exist in the mass range 2.8 – 5 GeV • Decays of higher mass resonances in the 4.2-4.5 GeV may be an excellent source of charmonium hybrids • (4.4-4.5) cross section ~ 10nb • Assume hybrids are produced in 10-3 of decays • Then in a 1 month run at SuperB: Antimo Panalano David HitlinITEP Meeting July 24, 2006 28

  29. Conclusions • There will be several areas of real interest in charm (and t) physics remaining after BESIII completes data-taking • Several charm measurements require running near charm threshold • These are typically Standard Model calibration or engineering measurements • Absolute hadronic, leptonic and semileptonic branching fractions • Pseudoscalar coupling constants • Measurements of d in correlations • Charmed baryon studies (abs. B) • Charmonium hybrid searches • Some of these measurements can also be done well in the (4S) region • Most New Physics-related measurements are better done in the (4S) region David HitlinITEP Meeting July 24, 2006 29

  30. Conclusions, continued • A low energy program at a Super B Factory could be developed by “stealing” one month per year from the primary B physics program • It is possible to do so at some (small) capital cost, which would be partly offset by power savings • Whether this is worth doing or not depends to some extent on the state of New Physics explorations at the LHC, on the accomplishments of BESIII, and on the progress of lattice QCD • Whether or not a Super B Factory has low energy running capability, it will produce significant new results in t and charm physics David HitlinITEP Meeting July 24, 2006 30

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