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Charm and  Decays

Charm and  Decays. Results from Babar and Belle Jens Sören Lange (University of Giessen) 43 th Rencontres de Moriond QCD and High Energy Interactions La Thuile. March 9, 2008. Outline. Charm Decays D sJ decays into D*K: D s1 (2536) into DK: D sJ (2700), D sJ (2860)

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Charm and  Decays

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  1. Charm and  Decays Results from Babar and Belle Jens Sören Lange(University of Giessen)43th Rencontres de MoriondQCD and High Energy Interactions La Thuile. March 9, 2008

  2. Outline Charm Decays • DsJ decays into D*K: Ds1(2536)into DK:DsJ(2700), DsJ(2860) • Ds+!+  , fDs • Charmed baryons, c Decays • Hadronic  decayswith  in final state • Hadronic  decayswith  in final state

  3. Nucl. Instr. Meth A479(2002)117 Integrated Luminosity 773.7 fb–1 Nucl. Instr. Meth. A479(2002)1 Integrated Luminosity 512.2 fb–1

  4. Charm Production at B Factories • from B decays~99% of all B mesons decay into charm final states • in continuumcross section (~1.2 nb) is as high as B meson cross section (~1.1 nb) D+ D+ D– D–

  5. A brief history of DsJ states • Babar observed Ds0*+(2317)Ds+oPhys. Rev. Lett. 90(2003)242001 • Cleo observed Ds1+(2460)Ds+*oPhys. Rev. D 68(2003)032002 • Ds in final state> most probable assignment[c s] L=1 states • ~100 MeV too low comparedto early quark modelsGodfrey, Isgur, PRD 32(1985)189 • Properties of other states in Ds system?

  6. JP 2+ DsJ(2573) jq = 3/2 L = 1 D*K threshold 1+ Ds1(2536) D K threshold jq = 1/2 1+ Ds1(2460) 0+ Ds0(2317) [cs] multiplets There are two 1+ states, mass difference m ' 76 MeV ! investigation of mixing jq = sq + L, J = jq+ sQ L = 2 ….. mix? spin-orbit tensor spin-spin Ds* 1- jq = 1/2 L = 0 Ds 0-

  7. DsJ decays 0 DsJ+ Ds+ D0 DsJ+ K+

  8. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c DsJ Decays into D*K Ds1(2536)

  9. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c 1st Observation of Ds1(2536) in B Decays • B !D(*)D(*) K at Babar347 fb–1 , PRD-RC 77(2008)011102Ds1(2536)+! D*+Ks0, D*0 K+ • Analysis of Ds1(2536) helicityfor quantum number confirmation • JP=1+ in pure S-wavewould be flat • JP=1– in pure P-waveand JP=1+with S/D-wave admixturefit both well (2/n.d.f.=9.6/9 vs. 9.3/9) PDG2007 1- 1+ 2+,–disfavoured

  10. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c Observation of Ds1(2536)→D+π–K+ • Formerly known decay modes of Ds1(2536) ! D*+Ks! D*0K+! Ds +– • Bellee+e-→Ds1(2536)X462 fb-1 Ds1(2536)→D+–K+3-body1st observationDs1(2536)→D*+Ks2-bodyused for partial wave analysis 3-body 2-body hep-ex/0709.4184 PRD 77(2008)032001

  11. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c Partial Wave Analysis Ds1(2536)→D*+K0s • Mixing of jq=1/2 and jq=3/2 states • HQET prediction for P-wave cs states: • 1+(jq=3/2)→D*K should be pureD-wave decay • 1+(jq=1/2)→D*Kshould be pureS-wave decay • If HQET not exact: mixing of S/D waves possible (by LS interaction)

  12. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c Partial Wave Analysis Ds1(2536)→D*+K0s • Helicity formalism • Fit results (syst. errors): • S-wave dominates in Ds1(2536)→D*K(72  3  1)% might contradict HQET (c quark is not infinitely heavy)note: D-wave might be suppressed by centrifugal barrier • Ds1(2460) and Ds1(2536) mix 3-dim analysisprojections shown hep-ex/0709.4184 PRD 77(2008)032001

  13. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c DsJ Decays into DK DsJ(2700), DsJ(2860)

  14. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c New DsJ meson in B+→D0D0K+ • Belle, 414 fb-1 • DsJ(2700)dominating resonance in this B decay M(D0D0)>3.85 GeV (4160) reflection arXiv:0707.3491Phys. Rev. Lett. 100(2008)092001 DsJ(2700)

  15. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c D0 K+ Quantum numbers of DsJ(2700) →D0K+ • Helicity angle distribution • J=1 preferred • 1→0–0– decay implies L=1!negative parity • DsJ(2700) JP=1– state could be: • radial excitation 23S1predicted by potential models at m~2720 GeVClose, Swanson, PLB 647(2007)159 • chiral doublet state 1–to 1+ Ds1(2536) predicted from chiral symmetryat m=2721±10MeVNowak, Rho, Zahed, Acta Phys. Polon. B35, 2377 (2004) J=02/ndf=112/5 J=12/ndf= 11/5 J=22/ndf=146/5

  16. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c DsJ(2860) and DsJ(2700) at Babar and Belle • Babar, 240 fb–1in e+e– continuumPRL 97(2006)222001 • evidence for a new DsJ statem=2856.6±1.5±5.0 MeV=48±7±10 MeV • Babar observes 3 structures • Ds2(2573)+ • a broad structure peaking around 2.7 GeV! DsJ(2700)? • DsJ(2860)!not seen in Belle dataprobably in B decays suppressed by high spin? DsJ(2700)? DsJ(2860) Ds2(2573) DsJ(2700)? DsJ(2860)

  17. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c Ds+!+ '1 • Pure leptonic decay, mediated by single W boson • Br measurement allows determination of fDs

  18. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c Ds+!+  • Babar, 230.2 fb–1PRL 98(2007)141801489§55 events • Belle, 548 fb-1arXiv:0709.1340subm. to Phys. Rev. Lett.169§16§8 events • Signal peaks inM()–M()=143.5 MeVormrecoil(DKX)=m=0 • Background shapeDs+! e+suppressed by factor (m/me)2 ~105

  19. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c Ds+!+ and fDs • Comparison to theorysee Rosner, Stone, arXiv:0802.1043 • recent Lattice QCD calculationPhys. Rev. Lett. 100(2008)062002fDs=241§3 MeVa=0.09 fm, grid 283 x 96,incl. sea quarks • indication for new physics?

  20. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c cccc Charmed Baryons: Studies of the c system

  21. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c A brief history of c charmed baryons • c+K–+ final state is usedfor searches of double charm baryon ground states (ccq) weak decays • However, Belle observed two new statesc(2980)+,0!c+ Ks0–c(3077)+,0!c+ Ks0 • These are strong decays • Why is this surprising?formerly only knowndecays c* ! c  or c  • Here, the strange and the charm quark are observed in different hadrons Belle, hep-ex/0606051 Phys.Rev.Lett. 97(2006)162001

  22. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c Evidence for two new c states • Babar 384 fb-1Phys. Rev. D 77(2008)012002 • Confirmation ofc(2980) and c(3077) • Final state c K but require  invariant mass • Evidence for two new statesc(3055)+!c(2455)++ K–6.4(JP=1/2+) and c(3122)+!c(2520)++ K–3.6(JP=3/2+) • A new Puzzlewhy decay into c(isospin=1) K?usc ! uucus c(2980) c(3055) c(3077) Cut on c(2455) c(3122) c(3055) Cut on c(2520)

  23. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c Excited c Transistions • Belle, 414 fb-1, hep-ex/0802.3968 subm. to Phys. Lett. B • Is the c (2980) the first positive parity excitation of the c? (mass could be high enough) • Or higher radial (n¸2) excitation? • New decay mode observedc*(2980) !c*(2645)  • Single  transitions give hintsfor quantum number assignmente.g. c(2815)(3/2–) !c  is forbiddenc(2815)(3/2–) !c(2645)  ! c   seen by Cleo • This decay mode (assume S-wave) is predicted dominant for c1(½+) c(2815) c(2980)

  24. Ds1(2536)DsJ(2700)Ds!Charmed Baryons c Indication of another c state • BABARPRD-RC 77, 031101 (2008) 210 fb-1in B decaysB–! [K–c+] c–Dalitz analysis • c(2930) ? • Predicted density of states in this mass region is high

  25. Hadronic Tau Decays Hadronic  Decays with Hadronic  Decays with 

  26. Hadronic  Decays with Hadronic  Decays with   Decays with  final state • Belle, hep-ex/0708.0733485 fb-1, 446x106 +–Uncertainties on Br‘s improved by factor 4-6 • 3 pseudoscalar meson case:Wess-Zumino termmight increase Br by factor ¸10–! K–0Br = (4.7§1.1§0.4) x 10–5–!–0Br = (1.39§0.03§0.07) x 10–3 • –!–0also breaks G parity! suppressed by factor ~(md – mu)2 • Ongoing work(requires separation of resonant and non-resonant part)

  27. Hadronic  Decays with Hadronic  Decays with  F peak in t- K-p-K+n & t- K-K+K-n  Decays with  final state K-K+K- • BABAR342 fb–1Phys.Rev.Lett.100(2008)011801 • –! K+ K– K– • Cabbibo suppressed (Vus~0.2) • Resonant  is saturating! excluding , upper limit Br < 2.5 x 10–6 • consistent with BellePhys. Lett B643(2006)5

  28. Hadronic  Decays with Hadronic  Decays with  F peak in t- K-p-K+n & t- K-K+K-n  Decays with  final state K-p-K+ • BABAR342 fb–1Phys.Rev.Lett.100(2008)011801 • First measurement of –! K+ K– –Br = (3.42§0.55§0.25) x 10-5 • OZI suppressed –

  29. Summary • Results from Belle and Babar presented forDs1(2536), DsJ(2700), DsJ(2860), c**, Ds!, fDsHadronic  decays with  and  final statesThank you for your attention.

  30. Backup Slides

  31. Ds+!+ analysis technique • Analysis technique: • full reconstructione+ e–! Ds* D,0 K,0Xwhere X=n and · 1 • Tag side:DK, with D ! K n, n=1,2,3 • Signal side:Ds*! Ds (reconstructed in the recoilagainst DKX) • In the Ds sample • Require 1  • Use Ds!e eas background shape(expected Br factor ~105 smaller) 32100 §1490 inclusive Ds decays

  32. Ds+!+ Reconstruction Method Lauranz Widhalm, HEPHY

  33. Ds+!, Comparison of Analyses Belle • Efficiency depends strongly on number of pions • p*(D)>2.0 GeV/c • p*(Ds)>3.0 GeV/c • p*(K) < 2.0 GeV/cElab()>150 MeV • Mass-constrained vertex fitfor Ds* and Ds Babar • Efficiency cancels in partial width ratio (Ds+!+)/ (Ds+!+) • p*(+ )>1.2 GeV/c • *>38o • |p(Ds*+)| cut • E*>115 MeV • cos(,D)<0.9 • Emiss* cut

  34. Ds+!, Comparison of Backgrounds Belle • MC studies show • Non-Ds decays ~18% • Leptonic  decays ~7%(!) • Semileptonic Ds decays ~3.6%with undetected low p hadrons • Hadronic Ds decays <2% Babar • e+ e–! f anti-fwith no charmor incorrect tag ~42% • Leptonic  decays ~26%(!) • Pure leptonic D! or Ds! missing the signal chain~20% • Other backgrounds • charged  misidentified as  ~1% • incorrectly chosen  candidate ~10%

  35. fD • fD+=222.6§16.7 +2.8–3.4 MeVCLEOfor 47§7 D+!+ eventsPhys. Rev. Lett. 95(2005)251801 • Lattice fD+=208§4 MeV

  36. fB – Lattice QCD vs. Experiment • BellePhys.Rev.Lett. 97 (2006)251802 hep-ex/0604018v3414 fb-1 • Br(B-!–tau) = (1.79 +0.56–0.49(stat) +0.46–0.51(syst))*10–4 • This implies that fB = 0.229+0.036–0.031(stat) +0.034–0.037(syst) GeV • The B meson decay constant from unquenched lattice QCDHPQCD CollaborationAlan Gray et al.Phys.Rev.Lett. 95(2005)212001hep-lat/0507015

  37. Status of Charmed Baryons R. MizukarXiv:0712.0310

  38. Charmed Baryon 5/2 States • Rosner et al.hep-ph/0612332 • L ' 300 MeV 3122 3077 3055 2980 2940!D0p 2880!D0p c(2880)+!c(2455)0,+++,− 5/2+ 5/2- Belle

  39. Possible  transitions in c system • hep-ph/0610283Chen and Chui • L is orbital momentumof light quark

  40. G. Marchiori, NOW 2006

  41. D** • assume heavy quark symmetrymcharm • light quark couples to L first • thenL=1 states are 2 doubletsjq=1/2broad (decay by  S wave)jq=3/2narrow (decay by  D wave)

  42. D** • BELLE observes the two broad D** (jq=1/2) L=1 statesPhys. Rev. D69(2004)11200265.4 Mill. BB • mass widthD*0(J=0) 2308171528 MeV 276211860 MeVD´1(J=1) 2427262015 MeV 384+107-752470 MeV D+K+D*+Do+DoK+DoK++ D2* can decay to D and D*

  43. Confirmation of new DsJ States • BELLE confirmed bothand observed DsJ+(2460)Ds+ Phys. Rev. Lett. 92(2004)012002 • seen in both production mechanisms • e+ecc • B decay > important for determination of quantum number not Ds* !

  44. DsJ quantum numbers • observation in B decays enables helicity analysis (fixed initial state) JP=0+ JP=1-

  45. Theory Experiment Compare D and Ds systems • should be similar (except smaller mass splitting jq=1/23/2 due to s quark mass) • why are the Ds jq=1/2 states narrow (and the D states broad) ?isospin violation (from I=0 to I=1) • but measured DsJ masses >100 MeV lower than potential model

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