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New hadrons spectroscopy @ BaBar

New hadrons spectroscopy @ BaBar. Maurizio Lo Vetere University of Genova & INFN. Representing the Collaboration. Particles and Nuclei International Conference October 24-28, 2005 (PANIC05). Outline of the talk. Charmonium spectroscopy X(3870) Y(4260)

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New hadrons spectroscopy @ BaBar

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  1. New hadrons spectroscopy @ BaBar Maurizio Lo Vetere University of Genova & INFN Representing the Collaboration Particles and Nuclei International Conference October 24-28, 2005 (PANIC05)

  2. Outline of the talk • Charmonium spectroscopy • X(3870) • Y(4260) • Ds spectroscopy • D*sJ(2317) • DsJ(2460) • DsJ(2632) • Charmed barions • c+ • c0 @

  3. Charmonium spectrum States below open charm threshold well known and in agreement with potential models Most states above open charm threshold are missing. Those known have quantum numbers JPC=1- - because are produced through virtual  in e+e- annihilation Other kind of states are possible (DD* molecules, diquark-antidiquark, hybrids) DD* y’ DD hc’ hc ccJ y hc New states discovered at B factories. Among others: X(3872), Y(4260).

  4. The X(3872) observation Discovered by Belle(1) in B KX, XJ/yp+p-(compatible with J/yr0) BELLE PRL 92, 262001 (2003) CDF PRL 93, 072201 (2004) BABAR PRD 71, 071103 (2005) D0 PRL 93, 162002 (2004) MX= 3871.9 ± 0.5 MeV/c2slightly above D0D*0 threshold GX<2.3 MeV/c2 at 90%CL; JPC=1++favoured(2) (1) PRL 91, 262001; (2) hep-ex/0505038

  5. What is the X(3872)? • B(cc)K is a typical B decay mode • Isospin violating decay into J/yr0 would be against charmonium hypothesis • No state predicted at this mass • Exactly at DD* threshold Possible interpretations • Charmonium (1)(2) • D0-D0* molecule (3)(4) • Diquark-antidiquark state (5) • others… Need experimental result to test models: • Quantum numbers, decay modes, possible charged partners (1) Barnes et all. , PRD 69, 054008 (2004) (2)Eichten et all., PRD 69, 094019 (2004) (3) Swanson, PLB 588, 189 (2004) (5) Maiani et all., PRD 71, 014028 (2005) (4) Tornqvist, PLB 590, 209 (2004)

  6. BX(3872)K, X(3872)J/yp+p- 211 fb-1 hep-ex/0507090 B±X(3872)K± If X(3872) is a charmonium state models predict similar production rates in B0 and B+decays; If X(3872) is a DD* molecule, models(1) predict suppression in B0 decays; If X(3872) is a tetra-quark: states produced in B0e B+ decays differ and it is expected Dm ~ (7 ± 2) MeV/c2 (2) Babar preliminary 6.1s B0X(3872)Ks (1)Braaten and Kusunoki, PRD 71, 074005 (2005); (2)Maiani et all. , PRD 71, 014028 (2005). Babar preliminary 2.5s More data needed to discriminate between models

  7. y’ 3.872 m(J/yh) GeV/c2 Search for X(3872) charged partners 212 fb-1 B0X-(J/yp-p0)K+ B-X-(J/yp-p0)Ks PRD 71, 031501 (2005) Isospin multiplet predicted by molecolar models: BR(B X-K) ~ 2 BR(B X0K) No charged partner observed Isovectors rejected @ C.L.10-4 Search for BX(3872)K, XJ/ 82 fb-1 PRL 93, 041801 Some models(1) predict large branching ratios No signal observed (1) PLB 574, 210

  8. Inclusive charmonia in B decay 210 fb-1 B±XCCK± K± X Recoil B Y(4S) Reconstructed B • Novel variation on the recoil techniqueMeasurement of the K± momentum spectrumin B center-of-mass frame • No signal is observed for B+X(3872)K+: • BR(B+ X(3872)K+) < 3.210-4  • BR(X(3872) J/+–) >4.2%, 90% C.L. • No signal is observed for charged partners • in B0X(3872)+K-: • BR(B0X (3872)+K-)<5·10-4 at 90% C.L. Babar preliminary Recoil Mass High mass states: cc1, y’, y’’ and hc’ seen

  9. The Y(4260) observation 233 fb-1 hep-ex/0506081 e+e- gISR J/y(l+l-) p+p- No X(3872) evidence. No (4040), (4160), (4415). Observed (>8) a broad structure Y(4260): N = 125 ± 23 M = 4259 ± 8+2-6 MeV/c2  = 88 ± 23+6-4 MeV/c2 (Ye+e-) · BR(YJ/yp+p-)=5.5±1.0+0.8-0.7 eV/c2 JPC=1-- Impossible to distinguish between 1 or more resonances. Babar preliminary  may go undetected

  10. 4.260 GeV Search for Y(4260) in B decay 211 fb-1 hep-ex/0507090 B±Y(4260)K±;Y(4260)J/yp+p- Excess of event observed at 4260 MeV M, G fixed to the ISR analysis values N = 128 ± 42 events Significance: 3.1s BR(B-YK-)·BR(YJ/yp+p) = (2.0±0.7±0.2)×10-5 Babar preliminary R measurements compatibility (e+e-Y(4260)  J/ +-) ~4% (e+e-hadrons) BR(Y J/ +-) must be high despite state above D(*)D(*) threshold

  11. Charmonium summary • X(3872) (1) • Observed in neutral and charged B decay: • BX(3872)K, X(3872)->J/+- • BR( X(3872)->J/+- )>4.2% @ 90% C.L. • No isovector charged partners observed • No X(3872)->J/ decay observed • Not seen in ISR events • Y(4260) consistent with assignment JP=1--: • recently observed by Babar in ISR events • evidence for B± -> Y(4260)K± decay • statistic doesn’t allow to distinguish between one or more state hypotheses • Further investigations are needed to understand the nature of these states. • (1) BELLE favuor JP=1+ assignement.

  12. New charmed mesons Four states known before B-factories data Ds(1968)+, Ds*(2112)+, Ds1(2536)+, Ds2*(2573)+ in good agreement with theoretical predictions. Two new states discovered by BABAR(1) and CLEO(2): DsJ*(2317)+ (into Ds+0 ), DsJ(2460)+ (into Ds*+0). • Missing 0+,1+ states? • Masses significantly lower than predictions. • Isospin violation decay. SELEX(3) claims a state at M= 2632 MeV decaying into Ds+ and D0K+. Quantum numbers needed • Other possible interpretations? • tetraquark(4) or molecules(5). (1) PRL 90, 242001; (2) PRD 68, 032002; (3) PRL 93, 242001. (4) PRD 71, 014028; (5) PRD 68, 054006

  13. DsJ*(2317)Ds0 and DsJ(2460)Ds*0 123 fb-1 hep-ex/0408067 High Ds* sideband DsJ(2460) DsJ*(2317) DsJ*(2317)ɣ Ds*ɣɣ Ds*ɣ DsJ(2460)Ds*(Dsɣ)0 DsJ(2460) Low Ds* sideband m(DsJ*(2317))=2318.90.3(stat.) 0.9(syst.) MeV/c2(below D(*)K threshold) m(DsJ(2460))=2459.11.3(stat.) 1.2(syst.) MeV/c2(below D*K threshold)

  14. DsJ(2460) Reflections: DsJ*(2317)Ds0(ɣɣ) DsJ(2460)Ds0 (ɣɣ)ɣ More Dsj(*) decay modes 123 fb-1 hep-ex/0408067 Search for radiative and dipion transitions in order to confirm or rule out someof these hypotheses Ds+ɣ (JP=1,2,…) Ds++- (JP=0-,1,2…) Ds1(2536) DsJ(2460) DsJ*(2317) DsJ(2460)Dsɣ excludesJP=O± Absence consistent with JP=0+; allowed for all other natural parity

  15. Side bands m(DsJ(*)) fit results Search for B  D(*) DsJ(*)+ 113 fb-1 hep-ex/0408041 Compatible with predictions from: Bardeen et all., Phys.Rev. D68, 054024 (2003) • qh helicity angle for DsJ(2460)  Ds. Solid line expectation for J=1, dotted line expectation for J=2. J=1 good agreement J=2 excluded

  16. DsJ*(2317)0 DsJ*(2317)++ Search for DsJ(*) isovector partners 123 fb-1 hep-ex/0408067 Some authors*have discussed the possibility of a four quark content in DsJ states in order to explain the low mass of these states • T. Barnes, F.E.Close and H.J.Lipkin, Phys. Rev., D68, 054006(2003) • H. J. Lipkin, Phys. Lett. B580, 50(2004) • T.E. Browder, S. Pakvasa, and A. A. Petrov, Phys. Lett. B578, 365(2004) BaBar sees no evidence for DsJ(2317)0Ds+ - or DsJ(2317)++Ds+ +

  17. Search for DsJ(2632) Ds ,D0K+,D*Ks 125 fb-1 • Ds+(1020)+, K*(892)0K+ • ɣɣ where • ɣ0ɣɣ • ɣDs*+Ds+ɣ hep-ex/0408087 BaBar sees no evidence for DsJ (2632)  Ds, D0K+, D*+Ks

  18. DsJ mesons summary • DsJ*(2317)+ consistent with assignment JP=0+: • observed in Ds*0 system • not seen in Ds* or Ds* +  - • DsJ*(2460)+ consistent with assignment JP=1+: • observed in Ds*0 ,Ds+ , Ds*+ - • helicity in B  DDsJ(2460)+ decays consistent • No evidence for isovector DsJ*(2317)+ partners • No evidence for DsJ*(2460)+ state Evidence so far points out that DsJ may be interpreted as two ordinary cs mesons; yet the low mass of the DsJ states has still to be understood.

  19. C+ mass measurement Best measurement from CLEO (1) (1) P. Avery et al., Phys. Rev. D43, 3599 BABAR: large sample of charmed hadrons high momentum and vertex resolution well known alignment precise knowledge of field and material distribution Systematic uncertainties scale with Q-value: a  b + c + … Q = m(a) - m(b) - m(c) - … JP = ½ + We choose to recostruct C+ in its lower Q-value final states: c+ 0 KsK+( 0p- , Ks+-)Q-value: 178 MeV/c2 c+0KsK+ ( 0 0 ) Q-value: 101 MeV/c2 Systematic uncertainties considerably smaller than higher statistic modes: c+pK-+ Q-value: 713 MeV/c2 c+pKs Q-value: 850 MeV/c2

  20. c+ 0KsK+, 0KsK+ 232 fb-1 hep-ex/0507009 Higher statistic and Q-value mode: systematic errors dominate c+ 0KsK+ c+ 0KsK+ 4627 events 267 events Lower statistic and lower Q-value mode: statistical errors dominate

  21. Systematic uncertainties • Materials effect • Main syst. uncertainty due to energy loss corrections due to detector materials • Ks0,  fitted mass values indicate under-estimated amount of material • Fitted masse values studied as a function of radial decay distance • Largest deviations at low decay radii Increased SVT density by 20% in track reconstruction algorithms • Magnetic field effect • Solenoidal field well measured • Effects due to PEP II permanent magnet material magnetized by solenoid field Increased magnetization of PEP II magnets by 20% Systematic effects evaluated and assigned proper error m( c+ 0 KsK+ ) = 2286.501 ± 0.042 (stat) ± 0.144 (syst) MeV/c2 m( c+ 0 KsK+ ) = 2286.303 ± 0.181(stat) ± 0.126 (syst) MeV/c2 combined measurement: m( c+) = 2286.46 ± 0.14

  22. Backups

  23. BaBar detector SVT: 97% efficiency – 20mm z resol SVT+DCH: s(pt)/pt=0.13%·pt+0.45% EMC: s(E)/E=2.32%·E-1/4+1.85% 1m

  24. Experimental technique C=+1 C=-1

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