Open Charm Spectroscopy Klaus Peters GSI/GU Frankfurt Nov 19, 2009 Mainz Charm Production at B-Factories D-Meson Spectrum D s -Meson Spectrum Spectroscopy in D (S) decays Outlook

Motivation Until 2003: D/D s spectra was not very exciting D (Godfrey,Isgur) Prediction Godfrey,Isgur/ DiPierro, Eichten Measurement 2Klaus Peters – Open Charm Spectroscopy

Motivation D Evidence for 2 new states4 new states (Godfrey,Isgur) (nat. J P ) Prediction Godfrey,Isgur/ DiPierro, Eichten Measurement After 2003: Further states, partly very narrow (D s system) inconsistent with theoretical expectations  D s0 *(2317), D s 1(2460) 3Klaus Peters – Open Charm Spectroscopy

Motivation Nature of the recently found states? - cu/cd, cs states (+c.c.) - tetraquark states (e.g. csdd) - molecular states (near threshold, e.g. cd-ds) Experimental observables - masses - lifetime/width/partial decay widths - spin-parity - isospin (via decay) - mixing angles (singlett, triplett) 4Klaus Peters – Open Charm Spectroscopy

qq Charm Production at B-Factories Resonant e + e -  γ *  bb favored decay: b  c W - non-resonant qq production: e + e -  γ *  qq cc-events rich source for D and D s mesons e+e-e+e- σ [nb] bb1,05 cc1,30 ss0,35 dd0,35 uu1,39 B 0, B +, B s b qq W+W+ c d c 5Klaus Peters – Open Charm Spectroscopy

6K. Peters - Charm Spectroscopy Heavy-Light Systems Heavy qq ordered by L approximate L degeneracy m(η c )≈m(J/ψ) m(χ c0…2 )≈m(h c1 ) Light qq spectra as well same structure In Heavy-Light systems like H-atom ordered by property of the light quark approximate j degeneracy But the large gap between j=1/2,L=1 and j=3/2,L=1 was unexpected L=0L=1 J P =1 - J P =0 - J P =1 + J P =0 + J P =2 + η ω f0f0 f1f1 h1h1 f2f2 S=s 1 +s 2 J=L+S j=L+s L J=j+s H DsDs Ds*Ds* D sJ * D s1 D sJ D sJ * not to scale M M } j=1/2 } j=3/2 ηcηc J/ψ χ c0 χ c1 h c1 χ c2

L = 0 jqjq D-Meson Spectrum S-wave states (L=0) D 0 /D ± Mark I, 1975 D *0 /D *± Mark I, 1975 P-wave state candidates (L=1) D 0 * (2400) Belle, 2004 D 1 (2420) Argus, 1986 D 1 ‘ (2430) Belle, 2004 D 2 * (2460) E691, 1989 Neutral and charged states L = 1 mass 1/2 1/2 1/2 1/2 3/2 3/2 Experiment Theory Godfrey,Isgur, Phys. Rev. D32, 189 (1985) 7Klaus Peters – Open Charm Spectroscopy

D-Meson Spectrum predicted broad narrow Decay S-wave, ~ q 2L+1  q Decay D-wave ~ q 2L+1  q 5 q breakup momentum Mass / 8Klaus Peters – Open Charm Spectroscopy holds also for D s

D 0, D ± - Production D0D0 D±D± First seen in continuum events 232 fb -1 Phys. Rev. D (2006) D 0, 2006 Mark I, 1975 D0D0 9Klaus Peters – Open Charm Spectroscopy shows the extreme qualitiy of data, which every new generation has to compete with

D 2 * (2460) - Production First observed in γN  (D)X B  (D)B  (D*) In B decays e + e -  (D)X 62 fb -1 Phys. Rev. D (2004) E691, 1989 Argus In continuum 10Klaus Peters – Open Charm Spectroscopy progress is not as gigantic as with light D mesons  reason: very complicated final state

D 1 (2420) – Production and Decays e + e -  (D * )X and D *  D First observed in continuum B-Decays B  (D * ), B  (D) a) 62 fb - 1 Phys. Rev. D (2004) b) 145 fb -1 Phys. Rev. Lett (2005) a) Argus, 1986 b) 11Klaus Peters – Open Charm Spectroscopy Angular analysis consistent with spin 1 Phys. Lett. B232, 398 (1989) Argus, 1989

D 0 * (2400) – Production, Parameters  11P0 11P0 Only decay mode D J P = 0 + favored First observed in B  (D Focus (seen in γA) Use decay pattern for indirect J P measurement Allowed decay modes for J P = 0 + D 1 + D *  2 + (D, D * ) m = 2308 ± 17 ± 22 MeV/c 2 = 276 ± 21 ± 63 MeV m = 2407 ± 21 ± 35 MeV/c 2 = 240 ± 55 ± 59 MeV 100 MeV difference m = 2403 ± 14 ± 35 MeV/c 2 = 283 ± 24 ± 34 MeV 62 fb -1 Phys. Rev. D (2004) Phys. Lett. B586, 11 (2004) 12Klaus Peters – Open Charm Spectroscopy

D 1 (2430) – Production, Parameters… B 0  (D *+  - )ω 221 fb -1 Phys. Rev. D (2006) M = 2477 ± 28 MeV/c 2 = 266 ± 97 MeV No evidence for the narrow resonances at 2420 and 2460 MeV/c 2 ? Color suppressed B ±  (D * ) First seen in B decays Color favored M = 2427 ± 36 MeV/c 2 = 384 ± 117 MeV 62 fb -1 Phys. Rev. D (2004) D 1 (2430) Only decay mode D *  J P = 1 + favored 13Klaus Peters – Open Charm Spectroscopy

D s -Meson Spectrum States known until 2003 L = 0L = 1 1/2 1/2 1/2 1/2 3/2 3/2 jsjs cs + c.c. 14Klaus Peters – Open Charm Spectroscopy (CLEO, 1983) (Argus, 1989) (Cleo, 1994) (PEP4, 1984)

(BaBar, 2003) (BaBar, 2006) (Cleo, 2003) (BaBar/Belle 2006) Discovered after 2003 L = 0L = 1 1/2 1/2 1/2 1/2 3/2 3/2 jsjs natural spin parity D s -Meson Spectrum States known until 2003 (CLEO, 1983) (Argus, 1989) (Cleo, 1994) (PEP4, 1984) cs + c.c. 15Klaus Peters – Open Charm Spectroscopy

D s0 * (2317) + - Production cc continuum events first observation of this state by BaBar in e + e -  D s +  0 +X B decays first seen in B-decays by Belle B  D s0 * (2317)D, D s0 *  D s  0 Bckgr.1) D s *  D s   2) D s * (  D s )+wrong  3) D s1 (2460) (  D s  0 )-missing  1) 2) 3) 232 fb -1 Phys. Rev. D (2006) B  D s0 * (2317)K 368 fb -1 hep-ex/ Klaus Peters – Open Charm Spectroscopy

D s0 * (2317) + – Parameters and Decays Mass m = ± 0.6 MeV/c 2 Decay width  < 3.8 MeV (PDG 08) Observations - Mass too low compared with old potential models (Godfrey, Dipierro) New models work better - Mass lies below DK threshold  only isospin-violating and electromagnetic decays possible  Explanation of small width Very narrow 17Klaus Peters – Open Charm Spectroscopy

D s0 * (2317) + – Parameters Decay pattern J=1 J=0 261 fb -1 Belle Conf 0461 (2004) B  DD s0 *, D s0 *  D s   Spin-Parity J P = 0 + Angular distribution D s0 ¤ (2317) +    0 B D s (D s0 -CMS) D s0 (B-CMS) HH 18Klaus Peters – Open Charm Spectroscopy

D s0 * (2317) + – Nature of State Molecular state? Search for D s0 * (2317) 0 and D s0 * (2317) ++ companions no signal in D s +  - and D s +  + Isospin = 0 compatible with cs state D s0 * (2317) 0  D s +  - D s0 * (2317) ++  D s +  fb -1 Phys. Rev. D (2006) 19Klaus Peters – Open Charm Spectroscopy

D s0 * (2317) + – Nature of State Lots of tools Production in B-decays (HQET) Radiative production (D s -cascade) Radiative decays Hadronic decays Everything we know points to a cs state, which is lowered in mass due to chiral corrections But more exciting interpretations are still not excluded need a flavor factory for more precise BR Need a pp facility to measure or get better limits on the with All this also holds for the next object in this talk 20Klaus Peters – Open Charm Spectroscopy

D s1 (2460) + - Production cc continuum events first observation of this state by CLEO in e + e -  D s *  0 +X B decays first seen in B decays by Belle in B  D s1 (2460)D 368 fb -1 hep-ex/ B  D s1 (2460)K 232 fb -1 Phys. Rev. D (2006) 21Klaus Peters – Open Charm Spectroscopy

22 BUT – already in April 2003 BABARBABAR Klaus Peters – Open Charm Spectroscopy

D s1 (2460) + – Parameters and Decays Mass m = ± 0.6 MeV/c 2 Decay width  < 3.5 MeV (PDG 08) Observations -Mass too low compared with old potential models (Godfrey, Dipierro) New models work better - Mass lies below D*K threshold Missing modes: more statistic needed 23 Klaus Peters – Open Charm Spectroscopy

D s1 (2460) + – Parameters B  DD s1 D s1  D s  Angular distribution J=1 J=2  Spin-Parity J P = fb -1 Belle Conf 0461 (2004)  J=1 Continuum, D s1  D s *  fb -1 Phys. Rev. D (2006) J P = 1 +, 2 -, 3 +, … J P = Klaus Peters – Open Charm Spectroscopy

D s1 (2460) + – Nature of State Different branching fractions  not from same spin doublet Relative Branching fractions There are two 1 + states, (D s1 (2460) +, D s1 (2536) + ) mass difference m ~ 76 MeV  investigation of mixing with D s1 (2536) + seem to be small ! Mixing angle 25Klaus Peters – Open Charm Spectroscopy

D s1 (2536) + - Production cc continuum events first seen in e + e -  D * K, D *  D B decays first seen in B decays by BaBar B  D (*) D (*) K ARGUS 1989 D  K, K D  K 0 Large signals observed  very precise Measurements of mass and width possible 347 fb -1 Phys. Rev. D (2008) 26Klaus Peters – Open Charm Spectroscopy

D s1 (2536) + - Parameters 232 fb -1 hep-ex/ (preliminary) First measurement of D s1 (2536) decay width: Large signals  Precise measurement of mass, width continuum events e + e -  (D * + K)X, D * +  D 0  + PDG: ± 0.6 ± 0.1 MeV/c 2 27Klaus Peters – Open Charm Spectroscopy

D s2 * (2573) + – Production and Decays No angular distribution measured Decay mode consistent with events First seen in cc continuum Inclusive study of e + e -  (DK)X Large signal: Improvement in precision for D s2 (2573) Phys. Rev. Lett (2006) 240 fb -1 13P213P2 CLEO 28Klaus Peters – Open Charm Spectroscopy

D sJ * (2700) + - Production Seen by Babar in cc continuum Inclusive study of e + e -  (DK)X Seen by Belle in B + → D 0 D sJ (2700) +, D sJ (2700) + → D 0 K + Phys. Rev. Lett (2008) 414 fb -1 Same state? Phys. Rev. Lett (2006) 240 fb -1 29Klaus Peters – Open Charm Spectroscopy

D sJ * (2700) + – Parameters Possible interpretations - Radially excited 2 3 S 1 (excited D s * ) predicted mass ~2720 MeV/c 2 [ref 1] - Chiral doublet 1 - state to 1 + D s1 (2536) + predicted (2721 ± 10) MeV/c 2 [ref 2] Confirmation needed !! preferred angular distribution J P =1 - 1) Godfrey, Isgur PRD 32, 189 (1985) Close et al., PLB 647, 159 (2007) 2) Nowak et al., Acta Phys. Pol. B 35, 2377 (2004) final state  natural spin-parity J=1 J=0 J=2 Phys. Rev. Lett (2008) 414 fb -1 30Klaus Peters – Open Charm Spectroscopy Important !! D * K and D s (*) η

D sJ * (2860) + - Production, Parameters … D sJ * (2860) First observed in e + e -  (DK)X D sJ * (2860) not seen in B decays.  high spin for this meson ?  high spin supports small width D * K and D s (*) η important final state  natural spin-parity Phys. Rev. Lett (2008) 414 fb -1 Phys. Rev. Lett (2006) 240 fb -1 31Klaus Peters – Open Charm Spectroscopy

Dalitzplot Analysis for D-Decays Lorentz invariant, and phase space flat. – Allows resonance parameters and spin to be well measured. – Starts from a well-defined spin 0 particle – Expect intermediate resonances to have J≤2 (because of limited two-body-mass range, and centrifugal barrier suppression) – however, parity and isotopic spin are not conserved in the decay Charm Dalitz plots have many uses: – New measurements in light meson spectroscopy – Key role in CKM-measurement – Fundamental information needed to understand heavy mesons decay – Mixing and CP violation studies 32Klaus Peters – Open Charm Spectroscopy

D0 K0π+π-D0 K0π+π- 33Klaus Peters – Open Charm Spectroscopy Relevant for measurement of γ in B  DK Belle BW, 2σ resonances but χ 2 =2.72 arXiv: , Phys.Rev.D73:112009,2006 Babar K-Matrix, χ 2 = ,000 events Phys.Rev.D78:034023,2008

Model independent D +  K - π + π + E791 Phys.Rev.D73:032004,2006 Kπ P-wave  K ∗ (892),K ∗ 1 (1410),K ∗ 1 (1680) Breit-Wigners. Kπ D-wave  K ∗ 2 (1430) Breit-Wigner. Kπ S-wave extracted by spline- interpolation over 40 points. At each point amplitude and phase are free parameters. c 0 (s k )eiφ 0 (s k ) Kπ S-wave: Broad structure with dip at the K ∗ 0 (1430) resonance. 34Klaus Peters – Open Charm Spectroscopy

some more details LASS curve normalized to the E791 data at 1.3 GeV. Phase normalized to the same mass shifting down by 700. Watson theorem requires elastic phase to be the same 35Klaus Peters – Open Charm Spectroscopy

Model independent D +  π - π + π + 36Klaus Peters – Open Charm Spectroscopy Phys. Rev. D 79, (2009)

Scalar studies in semileptonic D (s) decays Scalar waves are always problematic and unambiguous coupled channels are hard to identify (overlaps, crossings etc.) New concept: Semileptonics D s -decays Example: e + e -  ψ(4040)  D s + D s - and D s +  ππl + ν (π + π -, π 0 π 0 )  η (‘) η (‘) l + ν  KKl + ν (K S K S, K + K - ) and l=e,μ  Model independent analysis possible  Use K-Matrix to analyze data  Coupled channel fit simple 37GSI - Group Report for M M M W M M M W or lν

Outlook for the D (S) -Spectrum  Necessary ingredients to differentiate among models accurate total width measurements / partial decay widths hadronic and radiative transitions to D s0 * (2317)/D s1 (2460) from higher mass states test of mixing schemes  Tools ongoing BaBar / Belle / Cleo / CDF / D0 analyses high luminosity B-factories LHCb (B s decays) charm production with FAIR (see T. Stockmanns) for the hadronic (light) D (s) -Decays ongoing BaBar / Belle analyses may be soon be superseded by BES3 38Klaus Peters – Open Charm Spectroscopy

D s1 (2536) + – Nature of State 1 + Mixing angle Belle: D s1 (2536) +  D * + K S 0, D * +  D 0  + D s1 is produced in e + e - continuum processes with (small) polarization Observables: 3 angles (,,) Fit to 3-dimensional angular distribution as function of polarization ( 00 = 2/3(1-w 3/2 )) and D/S-wave ratio Results:  00 = 0.49 ± ± (corresponds to HQET prediction) D/S = 0.63 ± 0.07 ± 0.02 x exp[±i(0.76 ± 0.03 ± 0.01)]  mixing angle (theoretical input) S-wave dominates contribution to total width ( S / total =0.72 ± 0.05 ± 0.01) in contrast to HQET prediction (SLAC-PUB-6311) Phys. Rev. D (2008) 39Klaus Peters – Open Charm Spectroscopy

40k. peters - experimental evidences for new charm-states D +  -  - Amplitude Analysis in B-Decays Belle

41k. peters - experimental evidences for new charm-states D *+  -  - Amplitude Analysis in B-Decays Belle

L = 0 Experiment Theory jqjq D-Meson Spectrum cu, cd ( = D 0(*), D +(*) ) and c.c. L = 1 ScSc j q = L + S q J = j q + S c 1/2 1/2 1/2 1/2 3/2 3/2 Heavy-light quark system HQET: spin S c decouples j q good quantum number Hydrogen-like not Positronium-like SqSq L q c Godfrey,Isgur, Phys. Rev. D32, 189 (1985) angular momentum L D 42Klaus Peters – Open Charm Spectroscopy

D s + – Parameters and Decays (PDG 08) ~ 100 decay modes studied: hadronic, (semi)leptonic  Dalitz Plot Analyses Ground state 1 1 S 0 J P =0 - (Spin assignment from angular analysis of , KK*) m = ± 0.34 MeV/c 2 c = m CLEO events First seen in continuum e + e -   X BABAR ,000 events 43Klaus Peters – Open Charm Spectroscopy

D s *+ – Parameters and Decays (PDG 08) m = ± 0.5 MeV/c 2 < 1.9 MeV Natural J P, decay modes consistent with J P = 1 -  1 3 S 1 First seen in e + e -  D s  X,D s  KK = M 2 (KK)-M 2 (KK) 60 events = M(KK)-M(KK) 15,600 events PEP-4 44Klaus Peters – Open Charm Spectroscopy

D s0 * (2317) + – Nature of State Belle: B 0 → D s0 * (2317) - K + Strange process: Both initial quarks undergo weak decay (bd  cssu ) Possible diagrams: a) PQCD factorization b) W exchange tree with FSI c) Exotic: Tetraquark 140 fb -1 Phys. Rev. Lett (2005) a) b) c) in constrast to HQET ~ 1 Conclusion: cs state, but other explanations not excluded 45Klaus Peters – Open Charm Spectroscopy