Charmed Meson Spectroscopy

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Charmed Meson Spectroscopy. Robert K. Kutschke Fermilab HQL04 June 4, 2004. For L=1:. Heavy-Light Mesons: Coupling Angular Mommenta. L. Spin of Q can be treated as a small perturbation. S q. q=u,d,s. Heavy Quark Symmetry (HQS):. S Q. - PowerPoint PPT Presentation

Text of Charmed Meson Spectroscopy

  • Charmed Meson SpectroscopyRobert K. KutschkeFermilab HQL04 June 4, 2004

    Heavy Quarks and Leptons. 2004

  • Heavy-Light Mesons: Coupling Angular MommentaSqHeavy Quark Symmetry (HQS):jl = total angular momentum of the light degrees of freedom.Spin of Q can be treated as a small perturbation.Main features understood by treating jl as a good Q#!q=u,d,sSQL

    Heavy Quarks and Leptons. 2004

  • P-Wave Charmed Mesons For each of cd, cu, cs, expect two doublets: Narrow doublet:JP = ( 2+, 1+) jlight = 3/2 D(*)p decay: D wave. G O( 10 MeV ) All well established.Broad doublet:JP = ( 1+, 0+) jlight = D(*)p decay: S wave. G O( 100 MeV ) First observations recently.

    Heavy Quarks and Leptons. 2004

  • Cartoon of Dominant Decay ModesWhen permitted by conservation of Energy, J and P.

    Heavy Quarks and Leptons. 2004

  • Whats Overly Simplified in the Ideal Picture? Doublets may overlap ( which 1+ is more massive?)

    Are all states above Dp and DK thresholds? Is suppression of S wave widths complete? Ds1 right at threshold for D*K: Very narrow, G < 2.3 MeV/c2 @ 90% CL. Data suggests mostly S-wave!

    Heavy Quarks and Leptons. 2004

  • Where Were We at HQL02?All data consistent with simple picture of HQS.Narrow doublet well established: D0, D+, DS.Broad states not observed ( except for an unpublished CLEO result ).Delphi D still not confirmed by anyone.Whats New Since HQ&L 2002?Observation of the expected broad DJ states.Observation of two new narrow DSJ states which decay to DSp0 and DS*p0.Are these the expected broad states ?

    Heavy Quarks and Leptons. 2004

  • FOCUS Starting Point: D and D* SignalsK-p+K-p+p+p-K-p+p+D*+ D0p+

    Heavy Quarks and Leptons. 2004

  • FOCUS Phys. Lett. B586, 11-20 (2004)M(D0p+)Feeddown:Neutrals are unobservedBG Function:A,B,C,D Free parametersHorrible Fit!FOCUS

    Heavy Quarks and Leptons. 2004

  • Same problem for M(D+p-): Horrible FitM(D+p-)FOCUS explored many BG models but all failed.Idea: We expect a broad state so add one to the fit. Caveat: 2 broad statesFOCUS

    Heavy Quarks and Leptons. 2004

  • FOCUSAdd a single S-wave resonance to the fit.Get excellent fit quality.Fit is robust against many variations in background.Yield of broad resonance:18754 22008.5 stnd. dev.Relative yields of signals and feed-downs consistent with expectations.

    Heavy Quarks and Leptons. 2004

  • Add a single S-wave resonance to the fit.Get excellent fit quality.Fit is robust against many variations in background.Yield of broad resonance:9810 27003.6 stnd. dev.Relative yields of signals and feed-downs consistent with expectations.

    FOCUS

    Heavy Quarks and Leptons. 2004

  • Changing of the GuardTo date all published measurements of D** come from inclusive measurements.A more powerful way of doing charm spectroscopy is to look at the Dalitz plots in BD(*)pp Dalitz decays.The penalty is small product branching ratios.We have been waiting a long time for this.Remember the power of D Dalitz plots for light quark spectroscopy.CLEO CONF-99-6, unpublished, uses this technique but with partial reconstruction of the final state.Last year Belle submitted the first use of this technique with full reconstruction.

    Heavy Quarks and Leptons. 2004

  • Belle: hep-ex/0307021 To Appear in PRD.Good signal to background ratio. Delta E cut kills Feed-down.

    Heavy Quarks and Leptons. 2004

  • Belle BD+pp Dalitz PlotSignal RegionDE Sideband

    Heavy Quarks and Leptons. 2004

  • Resonances Included:Free M and G:D2*(2460)D0*Virtual States:B*D*0D+ p-All have significant fit fractions.Most new features established by interference effects.No constant term in final fit. It does not improve the likelihood.Belle

    Heavy Quarks and Leptons. 2004

  • BelleBelleSignal RegionDE SidebandBelle BD*+pp Dalitz Plot

    Heavy Quarks and Leptons. 2004

  • Resonances included:D2*(2460)Free M and G D1(2420)D1(broad)Virtual States:B*D*All have significant fit fractions.Most new features established by interference effects.No constant term in final fit. It does not improve the likelihood.Belle

    Heavy Quarks and Leptons. 2004

  • Summary of D2* Data

    Heavy Quarks and Leptons. 2004

  • Summary of Data for D1(2420)0

    Heavy Quarks and Leptons. 2004

  • FOCUS measurements are of an unknown superposition of D1*0 and D10. So it does not make sense to take an average of BELLE and FOCUS.

    Heavy Quarks and Leptons. 2004

  • Summary of Charm Non-Strange SpectroscopyBroad states have now been seen.Above threshold for decay to D(*)p.Masses and widths approximately as expected.Angular distributions in the B Dalitz plots supports the conventional spin parity assignments:D1(2427): 1+D0*(2308): 0+ Mass ordering of the two 1+ states is not yet resolved.More statistics will help, especially the broad states.

    Heavy Quarks and Leptons. 2004

  • A Surprise from BaBar: PRL 90, 242001 (2003)Could this be the DS*0?Mass is below most, but not all predictions, Nowak, Rho and Zahed, PRD 49, 4370 (1993).Bardeen and Hill, PRD 49, 409 (1994).BABAR91 fb-1+Narrow peak in DSp0.JP = naturalWidth consistent with detector resolution, about 9 MeV.Mass near 2317 MeV.About 40 MeV below DK threshold.Second state near 2456?

    M(DSp0)

    Heavy Quarks and Leptons. 2004

  • Where to Look if DK and D*K are ForbiddenmixingIsospin violating! Cho and Wise, PRD 49, 6228 (1994)

    Heavy Quarks and Leptons. 2004

  • CLEO Sees Two StatesConfirms BaBar state at 2317 MeV.Establishes new state near 2460 MeV.

    Heavy Quarks and Leptons. 2004

  • Belle Confirms Both StatesM(Ds+ 0 )-M(Ds+)M(Ds*+ 0 )-M(Ds*+)Ds sidebands*Sidebands: DS solid, p0 dashed.

    Heavy Quarks and Leptons. 2004

  • A Conspiracy !Feed-down:DS(2460) DS*p0 (DS*g)p0Miss gamma and reconstruct as: DSp0Makes a narrow peak near 2317 MeV.Feed-up:DS(2320) DSp0.Add a random photon and require that DSg combination fall in DS* mass region. Plot mass of DSgp0 combinations.Makes a narrow peak near 2460 MeV.Most signal are about 75% pure and 25% feed up/down. CLEO, BaBar, Belle: different methods to deconvolve.

    Heavy Quarks and Leptons. 2004

  • Example: BaBars MethodPoints: M(DSg) in DS* region. Shaded: DS* sidebandSubtract distributions on the right.

    Heavy Quarks and Leptons. 2004

  • Belle: Two New Decay Modes of DS(2460)Forbids J=0DS1(2536) !DS(2460) Histogram: DS sidebands.DS(2320) DS*(2112)

    Heavy Quarks and Leptons. 2004

  • Belle: Sees the Decays BDDsJHistograms: DE sidebandsDs(2317)poDsDs(2460)poDs*Ds(2460)gDs2+1+DSJ FrameDSDS in B Frame

    Heavy Quarks and Leptons. 2004

  • Focus Sees DS(2317) in PhotoproductionHistograms: DS and p0 sidebands.First observation outside of e+e- at 10 GeV.M = 2323 2 MeV ( stat only; uses PDG DS mass).About 2 sigma above average of other experiments.Width consistent with detector resolution.Energy calibration: DS* DSp0 and D0 K-p+p0.

    Heavy Quarks and Leptons. 2004

  • Some Suggestions?HQS plus chiral symmetry explain low masses below DK threshold.Bardeen, Eichten & Hill hep-ph/0305049. Nowak, Rho & Zahed hep-ph/0307102.DK molecule Barnes, Close & Lipkin hep-ph/0305025Mixture with 4-quark state above DK threshold Browder et al. hep-ph/0307054Unitarized meson model Van Beveran & Rupp hep-ph/0305049Masses using QCD Sum RulesDai, Huang & Zhu hep-ph/0306274

    Heavy Quarks and Leptons. 2004

  • Some Suggestions?Can the lattice explain these as csbar states?No: Bali hep-ph/0305049,Yes: Dougall et al hep-ph/0307001On the importance of radiative decays:Colangelo & De Fazio hep-ph/0305140Godfrey hep-ph/0305122 Branching Fractions in B decay DDSJ are much smaller than for DDS. Factorization suggests that they should be similar. Is this a sign of non c-sbar nature?Chen and Li hep-ph/0307075 Datta and Odonnel hep-ph/0307106 Cheng and Hou hep-ph/0305038

    Heavy Quarks and Leptons. 2004

  • MiscellanyNo signals seen in DSp ( CLEO and CDF ).Excludes some molecule interpretations.

    Heavy Quarks and Leptons. 2004

  • Summary of New DS StatesM=2317.6 0.8 MeVM=2459.2 1.1 MeVG < 4.6 MeV (90% CL)G < 5.5 MeV (90% CL)JP=0+ FavoredJP=1+ Favored

    Heavy Quarks and Leptons. 2004

  • An Important Measurement to DoSet the scale of the partial widths. This will help sort out competing models.Hard to impossible with g and p0 final states.An idea:Measure the width of the DS1(2536).Better measurements of DS1(2536) DSpp.Measure: DS1(2536) DS(*)g.This can calibrate the models which can then be applied to the 0+ and 1+ states.

    Heavy Quarks and Leptons. 2004

  • Whats Interesting to do NextIncrease statistics on BD(*)pp Dalitz plot analyses.Improve measurements of the broad states and find charged broad 1+ state.Look for new states.Discover DS2 D*K.Dalitz plot analyses of B decays with DSJ in final state.This will be hard and require lots of data but Belle has shown that it is not out of the question.CDF, D0, LHC-b and BTeV. Combinatoric BG kills inclusive measurements.Should do well with analysis of B Dalitz plots.

    Heavy Quarks and Leptons. 2004

  • Summary and ConclusionsThe charmed-non-strange P-wave broad states are established with their expected properties.Waiting for BaBars results.Can CDF and D0 compete here?.The charmed-strange broad states are really strange. They are narrow!Below threshold for decay to D*K so they appear in unexpected decay modes, DS*p0, DSg and DSpp.Their JP are constrained but not fully determined.Lots still to do. Especially important to establish the widths of the narrow