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Charmed mesons

Charmed mesons. J. Brodzicka (KEK) for Belle Charm07, Ithaca US. Outline. J. Brodzicka for Belle @ Charm07. Introduction to c s multiplets Observation of D s1 (2536) → D + π - K + Partial Wave Analysis of D s1 (2536) → D* + K 0 s

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Charmed mesons

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  1. Charmed mesons J. Brodzicka (KEK) for Belle Charm07, Ithaca US

  2. Outline J. Brodzicka for Belle @ Charm07 • Introduction to cs multiplets • Observation of Ds1(2536)→D+π-K+ • Partial Wave Analysis of Ds1(2536)→D*+K0s • Observation of new DsJ(2700) →D0K+ in B+→D0D0K+ • Summary

  3. cs multiplets J. Brodzicka for Belle @ Charm07 jq = sq + L, J = jq+ sQ L = 2 JP ….. 2+ DsJ(2573) jq = 3/2 L = 1 1+ ? Ds1(2536) BaBar CLEO ‘03 Belle mix 1+ D*K jq = 1/2 ? 1+ 0+ Ds1(2460) D K 0+ D*s0(2317) spin-orbit tensor s-o spin-spin Ds* 1- jq = 1/2 L = 0 Ds 0- • HQS based potential model predictions • two doublets for orbitally excited L=1 cs states: (Godfrey-Isgur ‘85) • 0+, 1+ (jq=1/2) and 1+, 2+ (jq=3/2) • M(jq=1/2), M(jq=3/2) > MD+MK • Γ(jq=1/2) >> Γ(jq=3/2) Experiment: • jq=1/2 doublet 0+ : D*s0(2317)→Dsπ0 1+ : Ds1(2460)→D*sπ0 • jq=3/2 doublet 1+: Ds1(2536)→D*K(Argus ‘89) 2+: DsJ(2573)→DK(CLEO ‘94) jq=1/2 states:very narrow, masses below D(*)K →don’t match the potential model predictions

  4. Observation of Ds1(2536)→D+π-K+ J. Brodzicka for Belle @ Charm07 BELLE-CONF-0706 angular distribution studied for this Ds1(2536)→D*+Ks sample • Known decay modes of Ds1(2536) : D*+Ks, D*0K+, Dsπ+π- • Study of e+e-→Ds1(2536)X, Ds1(2536)→D+π-K+, D*+Ks • 462 fb-1 data sample used (normalization mode) • xP=pDs1/pmax >0.8 in e+e- cms • Two-body mass spectra consistent with Phase Space

  5. Mixing of jq=1/2 and jq=3/2 states J. Brodzicka for Belle @ Charm07 θ θ0 • HQET prediction for P-wave cs states: • 1+(jq=3/2)→D*K pure D-wave: Ds1(2536)→D*K • 1+(jq=1/2)→D*K pure S-wave: but Ds1(2460)→D*K forbidden • If HQET not exact: mixing of S-D waves possible (In Ds1(2536)→D*K D wave suppressed → small S-wave component can contribute much to the width) • Exp. knowledge on the mixing: • from BF’s ratio of Ds1(2460) radiative decays: D*sγ/Dsγ=0.31 ± 0.14 • switch from |jq>to |2S+1LJ >basis • tan2(θ+θ0)=0.8 ± 0.4 where tan2θ0=2 (no-mixing case)

  6. Partial Wave Analysis of Ds1(2536)→D*+K0s J. Brodzicka for Belle @ Charm07 BELLE-CONF-0706 • Angular distribution depends on α, β, γ angles defined as: • ρ: helicity density matrix; ρ00: probability of Ds1’s helicity=0 ρ11=ρ-1-1=(1-ρ00)/2 • √RΛ exp(iξ)=A10/A00A10 , A00: ampl. of D*‘s helicity= ±1, 0 ( A10 = (S+D/√2)/√3 A00 = (S-√2D)/√3 ) D/S =√ΓD/ΓS exp(iη)D, S: partial-wave ampl. in Ds1 decay • If no angle integrated → ξ-dependent term survives

  7. Fit to angular distribution of Ds1(2536)→D*+K0s J. Brodzicka for Belle @ Charm07 • 3D maximum-likelihood fit with PDF: • Background PDF: from M(D*+Ks) sidebands, normalized • fbck: background fraction in M(D*+Ks) signal region: ~9% • ε(α,β,γ)/<ε> → efficiency correction • Fit result projections (bckgd subtracted and efficiency corrected): • From χ2 of the fit: goodness-of-fit probability: 60%

  8. Results of Ds1(2536)→D*+K0sPWA J. Brodzicka for Belle @ Charm07 • Fit results (include systematic errors): • ΓS/ΓTOT = 0.72 ± 0.05 (η=43.9 ± 1.7°) S-wave dominates, contradicts HQET Ds1(2460) - Ds1(2536) mixing • Ds1’s helicity=0 preferred, agrees with HQET (aligned production of jq=3/2 states is predicted) • First full analysis for P-wave charmed mesons (CLEO integrated over βin PWA of D1(2420)→D*π)

  9. New DsJ meson in B+→D0D0K+ J. Brodzicka for Belle @ Charm07 hep-ex/0707.3491 (submitted to PRL) ΔE Mbc (4160) (3770) • b→ccs tree process; cs→D0K+ and cc→D0D0 states can contribute • B+→D0D0K+ signal identified using: ΔE=EB-Ebeam , Ebeam=√s/2 : cms energy difference Mbc= √E2beam-p2B : beam-constrained mass • S=399±40 for 449M BB pairs used • BF(B+→D0D0K+)=(22.2±2.2+2.6-2.4) x10-4 • Dalitz plot and mass projections different from 3-body Ph. Space new DsJ points: events from 1.5σ ΔE-Mbc signal box ■:background from sidebands

  10. Resonance contributions J. Brodzicka for Belle @ Charm07 fitted B signal yield ψ(4160) in ½ helicity distr. ψ(3770) • Non-coherent approach; possible interference effects included in syst. errors • 2D ΔE-Mbc fits in invariant mass bins → B signal extracted • Obtained background-free mass spectra used to estimate the resonance contributions: M(D0K+)for M(D0D0)>3.85 GeV fitted with: Breit-Wigner +ψ(4160) reflection + Ph. Space (shapes from MC) + exponential function (to describe the threshold enhancement (?) ) DsJ(2700)

  11. DsJ(2700) →D0K+ in B+→D0D0K+ J. Brodzicka for Belle @ Charm07 fitted B signal yield • Helicity angle distribution ofDsJ(2700): background free and efficiency corrected (reflections from threshold and ψ(4160) subtracted) • J=1 preferred; 1→0-0- decayimpliesP=-1 • Contributions to the observed mass spectra • Most observed features well described J=02/ndf=112/5 J=12/ndf= 11/5 J=22/ndf=146/5 ■DsJ(2700)■ψ(3770)■ψ(4160)■3body■threshold component (MC predicted shapes)

  12. DsJ(2700) interpretation J. Brodzicka for Belle @ Charm07 • DsJ(2700)→D0K+ 1- state can be: • radial excitation 23S1 (predicted by potential models at M~2720GeV) • chiral doubler state 1- to 1+ Ds1(2536)(predicted from chiral symmetry considerations at M=2721±10MeV) • BaBaR sees structure at M(DK)~2.69GeV produced in e+e- continuum. Is that due to DsJ(2700)? • DsJ(2860) observed by BaBar not seen in our data. Its production in B decays suppressed by its high spin? BaBar Coll. PRL 97, 222001 (2006) Godfrey, Isgur PRD 32, 189 (1985) Close, Swanson PLB 647, 159 (2007) Nowak, Rho, Zahed Acta Phys. Polon. B 35, 2377 (2004)

  13. Summary J. Brodzicka for Belle @ Charm07 • New info to cs multiplets: • new decay mode: Ds1(2536)→D+π-K+observed • from PWA of Ds1(2536)→D*+Ks (first full analysis for P-wave charmed mesons): • S-wave dominates: ΓS/ΓTOT = 0.72 ± 0.05 • Ds1(2536) and Ds1(2460) mix • longitudinal polarization: ρ00 = 0.490±0.013 → Falk-Peskin HQET parameter: w3/2 = 0.266 ± 0.019 • new DsJ(2700) meson observed: M=2708±9+11-10MeV Γ=108±26+36-31MeV JP=1- It opens a box of higher radial/orbital excitations of cs states

  14. J. Brodzicka for Belle @ Charm07 Backup

  15. Ds1 recoil mass study J. Brodzicka for Belle @ Charm07 • Ds1(2536) recoil mass: • Mrec spectrum indicates 2-body reactions: e+e-→Ds1(2536)X, where X=Ds ,D*s , higher D**s’s • Mrec resolution: ~70MeV at 2GeV, 1/Mrec dependence • 3D fits to angular distribution in bins of Mrec (RΛ and ξfixed) • Polarization at low Mrec: show structures expected for: e+e-→Ds1(2536)Ds ,Ds1(2536)D*s

  16. HQET Falk-Peskin parameter w3/2 (prob. of light quark’s helicities) • ρ00=2/3(1- w3/2) w3/2 = 0.266 ± 0.019 • (w3/2<0.24 @90%CL from D2*(2460)→Dπ by ARGUS) • Parameters: ρ00, RΛ, cosξ

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