CLEOc Hot Topics Ron Poling CLEO Collaboration and

CLEO-c Hot Topics Ron Poling CLEO Collaboration and University of Minnesota FPCP Vancouver April 9, 2006

Outline Introduction and overview of CLEO-c n Leptonic D decays n Semileptonic D decays n Closed and open charm production n Ecm=3970 – 4260 Me. V n Conclusions 9 April 2006 R. Poling – FPCP Vancouver 2

CESR-c CESR – 6. 5 Ge. V + 12(wigglers) Initial luminosity < original design. Various challenges, energy sensitivity in solenoid compensation →“antisolenoid” a la DA NE. Initial results: +20% instantaneous (6. 7 1031) and “best day” (4. 2 pb-1), expect >5 pb-1/day. CLEO-c CLEO III – SVX + ZD – 0. 5 T CLEO-c Still at the top of its game: p/p = 0. 6% at 1 Ge. V/c E/E = 2. 2% at 1 Ge. V, 5% at 100 Me. V Excellent electron and particle ID 9 April 2006 R. Poling – FPCP Vancouver 3

Goals and Impact of CLEO-c n n Significant input for worldwide CKM program, both direct and indirect Precision charm measurements + theory → reduced uncertainties in B measurements Validation of lattice for QCD and (potentially) other stronglycoupled theories Crucial “engineering” input for others: branching fractions for normalization modes, etc. 9 April 2006 R. Poling – FPCP Vancouver 4

CLEO-c Data Samples w (3770) – for D decays • • w Above (3770) – for Ds decays • • w w w Initial results from 57 pb-1 Updates with 281 pb-1 (some at FPCP) Preliminary – scan to determine optimal energy First run under way now (initial results at FPCP) (2 S) – one-stop charmonium shopping • Appetizer: 5. 6 pb-1 → 3 M (2 S) → 40 analysis results Scheduled to run through April, 2008. Luminosity improving, but still short of projections. What are the priorities for apportioning the remainder of the full CLEO-c data sample? (Stay tuned for “Conclusions”) 9 April 2006 R. Poling – FPCP Vancouver 5

D Physics at (3770)→DD D+→K- + + D-→K+ - - Tag D e+ + n n e. Signal D Tagging D gives pure sample of D of known 4 -momentum “Golden Modes” for best purity Additional modes (higher multiplicity, 0) for best efficiency Typical tagging efficiencies 15% for D 0 and 10% for D+. 9 April 2006 R. Poling – FPCP Vancouver 6

Tags in action… D Hadronic Decays (Details in talk of S. Stone) Single Tags n Double Tags Single Tags + Double Tags → Hadronic BFs • 57 pb-1 - PRL 95, 121801 (‘ 05) – update (281 pb-1) coming soon • 3 D 0, 6 D+ modes, including key normalization modes • Precision already comparable to PDG, benefits from cancellation of many systematic uncertainties 9 April 2006 R. Poling – FPCP Vancouver 7

Other CLEO-c Results on Hadronic D Decays § § § 9 April 2006 Non-tagged analyses, including Cabibbosuppressed decays D→ 2 to 5 pions. (Stone) Measurements of mixing, strong phases in D decays through quantum correlations at (3770) and above. (Cinabro, Stone) First results on hadronic decays of Ds. (Stone) R. Poling – FPCP Vancouver 8

Leptonic and Semileptonic D Decays See also the review from J. Wiss. B decays: use leptons to get to unknown Standard Model parameters. D decays: use leptons to master hadronic effects (LQCD training/testing). |Vcs| , |Vcd| c 9 April 2006 R. Poling – FPCP Vancouver W+ e+ 9

D+ → + Leptonic D Decays 281/pb PRL 95 251801 (’ 05) 160 K charged D tags (6 modes) Demand exactly 1 additional muon-like track, minimal extra energy. Mode Events Data 50 D+ + 0 1. 4 D+ Klong + 0. 33 D+ + 1. 08 Total Bck: 2. 81 BF(D+→ + )=(4. 4± 0. 7± 0. 1) 10 -4 f. D+ = (223± 17± 3) Me. V Same procedure, select e’s: BF(D+→e+ )<2. 3 10 -5 9 April 2006 (90% CL) f. D+ = (201± 3± 17) Me. V LQCD (PRL 95 251801, ’ 05) R. Poling – FPCP Vancouver 10

Leptonic D Decays D+ → + 281 pb-1 to be submitted to PRD Complementary info: SM/lepton universality predicts BF 2. 65 . Complementary analysis: selection of D+→ ( +→ + ) in events with tags selected as for D+→ +. Sample subdivided based on energy deposit of candidate track: (a) <300 Me. V and (b) >300 Me. V. Very slow MM 2 peaks at low values 9 April 2006 (a) (b) Signal Region 12 8 Estimated BG 6. 1± 0. 6± 0. 3 5. 0± 0. 6± 0. 2 Net 5. 9± 3. 5± 0. 3 3. 0± 2. 9± 0. 2 BF(D+→ + )<2. 1 10 -3 (90% CL) Ratio to SM rate <1. 8 R. Poling – FPCP Vancouver 11

Semileptonic D Decays § § § Cross-check with exclusives: saturation by lightest V & PS modes? Check equality of charged and neutral – evidence of WA? Input for others: BF and spectra. Use only purest tags: • • § § 281 pb-1 to be submitted to PRL Motivations: § § Inclusive D → Xe+ 47 K D 0→K- + (S/B 60) 74 K D+→K- + + (S/B 25) e ID by d. E/dx and RICH, p>200 Me. V/c Unfold right- and wrongsign electrons to obtain true lab-frame spectra. 9 April 2006 R. Poling – FPCP Vancouver 12

D → Xe+ Results § § § Lab-frame momentum spectra d /dpe Fit observed spectra to models, including FSR. Use results to correct for p<200 Me. V/c production. BF(D+→Xe+ )=(16. 13± 0. 20± 0. 33)% (Exclusive sum: 15. 1%) BF(D 0→Xe+ )=(6. 46± 0. 17± 0. 13)% (Exclusive sum: 6. 2%) (D+→Xe+ )=(0. 1551± 0. 0020± 0. 0035)ps-1 (D 0→Xe+ )=(0. 1574± 0. 0041± 0. 0032)ps-1 9 April 2006 R. Poling – FPCP Vancouver 13

D→Xe Exclusive with D Tags D+ PRL 95, 181801 (2005) D 0 PRL 95, 181802 (2005) * 57 pb-1 – 60 K D 0 tags, 32 K D+ tags Select semileptonic decays among non-tag tracks, requiring U = Emiss – c|pmiss| 0 ( 10 Me. V) * Note – Not updated with winter 2006 preliminary BES results. Upcoming: updated branching fractions with 281 pb-1 and form factors for Ke and e. Longer term: more modes, form factors in D→Ve. 9 April 2006 R. Poling – FPCP Vancouver 14

D→Pe Branching Fractions and Form Factors with Reconstruction CLEO-c Preliminary No D tag required: reconstruct semileptonic D decay from its decay products, including the . P Pmiss=Pevent – Pvisible Get all the true showers/tracks, no false ones or duplicates. q 2=(Pe+P’miss)2 P’miss= Pmiss ( gives E=0) Emiss (Ge. V) Tricks of the trade: Exclude impossible events! pmiss (Ge. V) q 2 (Ge. V 2) MC: Reconstructed – True for D 0→ +e- 9 April 2006 R. Poling – FPCP Vancouver 15

D→Pe Branching Fractions and Form Factors with Reconstruction Using the reconstructed and a signal K or , reconstruct D in the usual way: E = EK + Ee + |pmiss| - Ebeam Mbc = E 2 beam – (p. K + pe + p’miss)2 Mbc distributions fitted simultaneously in 5 q 2 bins to obtain d(BF)/dq 2. Integrate to get branching fractions and fit to obtain form-factor parameters. 9 April 2006 R. Poling – FPCP Vancouver 16

Mbc fits for the four D→Pe modes (all q 2) D 0→K-e+ D+→KSe+ D 0→ -e+ D+→ 0 e+ 9 April 2006 R. Poling – FPCP Vancouver 17

PRELIMINARY 9 April 2006 R. Poling – FPCP Vancouver 18

PRELIMINARY Form Factor Results Simp. Pole Mod. Pole 9 April 2006 R. Poling – FPCP Vancouver 19

PRELIMINARY Vcs and Vcd Results Combine |Vcx|f(0) with LQCD value for f(0) PRL 94, 011601 (2005) Precision comparable to exclusives with tags; much independent information. Combined results will give best precision. 9 April 2006 R. Poling – FPCP Vancouver 20

Open Charm and Charmonium Production in e+e- Annihilations ECM = 3970 -4260 Ge. V § Primary CLEO-c Motivations: • • § Determine optimal energy for Ds studies. Assess capabilities for D physics above (3770). Additional Objectives: • • Detailed study of “intricate behavior” of hadronic cross section in the region above opencharm threshold. Y(4260): confirmation, more details. § Scan Data Sample: • § First real Ds Run at 4170 Me. V: • • 9 April 2006 12 energies, 60 pb-1 Part 1: 76 pb-1 (results at FPCP) Part 2: under way, expected total >150 pb-1 R. Poling – FPCP Vancouver 21

Objective: Determine Optimal Energy for Ds Physics Procedure: Measure Cross Sections for 8 Event Types § Use 3 D 0, 5 D+, and 8 Ds+ modes to select charmed mesons. § Do not reconstruct D*, since momentum (or Mbc), differentiates event types. § For DD and Ds. Ds cut on E and use Mbc to extract yields. § For other event types cut on Mbc and use invariant mass to extract yield. § Cut values determined by kinematics – no double counting allowed, cross-feed small and calculable. 9 April 2006 MC D 0 K at Ecm=4160 Me. V D 0 in DD D 0 in D*D R. Poling – FPCP Vancouver MC D 0 in D*D* 22

Closer look: selecting Ds MC Ds Ecm = 4160 Me. V DD D s Ds. Ds* DD* D*D* 9 April 2006 R. Poling – FPCP Vancouver 23

Complication: Not all charm events fall into one of the 8 final states, with two charmed mesons and nothing else! Evidence for “multibody” (MB) events, e. g. e+e-→DD* : *D ** DD*D D 0 Momenta MC 4160 Me. V DT 4160 Me. V No MB Clear MB DD** DD DD DD 9 April 2006 R. Poling – FPCP Vancouver 24

PRELIMINARY Partial systematic uncertainties Multibody correction not applied Not radiatively corrected D*D Enhancement at D*D* threshold Plateau in D*D* Very little DD 9 April 2006 R. Poling – FPCP Vancouver 25

PRELIMINARY Partial systematic uncertainties Not radiatively corrected Location that maximizes the Ds+ yield. Peak structure in Ds. Ds 9 April 2006 R. Poling – FPCP Vancouver 26

Cross-Check: Inclusive vs. Exclusive PRELIMINARY Partial systematic uncertainties Not radiatively corrected § Exclusive: Sum of (up to) 8 modes with two charmed mesons (no MB) • Inclusive charm: D 0 + D+ + Ds ▲ Inclusive Hadrons: Excess over uds Good agreement between two inclusives. Excess of inclusive over exclusive reaffirms MB. 9 April 2006 R. Poling – FPCP Vancouver 27

§ Scan Conclusion § § Ds “Mini-Factory” at ECM=4170 Me. V has been selected and is in operation. (Ds. Ds*) 1 nb § § Precise value depends on Ds branching fractions. Analysis is under way of the first 76 pb-1 for the Ds program. Some preliminary results on hadronic Ds decays will be presented by Sheldon Stone on Tuesday morning. 9 April 2006 R. Poling – FPCP Vancouver 28

CLEO Investigations of Y(4260) Ba. Bar discovery CLEO III Confirmation PRL 95, 142001 (2005) PRELIMINARY – 4. 9 233 fb-1 13. 3 fb-1 Many possible explanations: hybrids, tetraquarks, molecular states, conventional (4 S)+QM e+e-→ ( + -J/ ) JPC=1 - …at a minimum in the cross section for e+e-→hadrons 9 April 2006 What can CLEO-c say? R. Poling – FPCP Vancouver 29

Charmonium Decays of (4040), (4160), and Y(4260) CLEO-c hep-ex/0602034 Submitted to PRL Search for 16 final states with J/ , (2 S), c. J, Use e+e-→ (2 S) to verify efficiency, background, luminosity. § § 9 April 2006 Y(4260)→ + -J/ confirmed (11 ) First observation of Y(4260)→ 0 0 J/ (5. 1 ) and first evidence for Y(4260)→K+K-J/ (3. 7 ), plus in-progress opencharm studies should narrow the explanations. R. Poling – FPCP Vancouver 30

CLEO-c: Summary and Prospects § CLEO-c is already having major impact on our knowledge of charm, with broader implications for all of flavor physics. § § Measurements of leptonic D decays, hadronic D decays, semileptonic D decays (including exclusive form factors), charm production, Y(4260), …. Excellent prospects for much more: § • Scheduled to run through April, 2008; plan designed to achieve maximum physics returns on the likely luminosity budget. 750 pb-1 at 3770 for D physics, 750 pb-1 at 4170 for Ds (and D) physics and 30 million psi(2 S). 9 April 2006 Quantity BF(D 0→K- +) BF(D+→K- + +) Exp. Precision 1. 25% 1. 4% BF(Ds→ +) 4% BF(D+→ ) BF(Ds→ ) 9% 9% BF(D 0→ -e+ ) |Vcd| 2. 3% 2% FF param. 0. 05 R. Poling – FPCP Vancouver 31