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Galina Pakhlova ITEP&Belle

International Workshop on Heavy Quarkonia 2008 2-5 December 2008, Nara Women's University. Galina Pakhlova ITEP&Belle. Charm components of R using ISR at Belle. R(s) = σ (e + e – → hadrons, s )/ σ (e + e – → μ + μ – , s). Two main reasons to know charm components of R.

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Galina Pakhlova ITEP&Belle

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  1. International Workshop on Heavy Quarkonia 2008 2-5 December 2008, Nara Women's University Galina Pakhlova ITEP&Belle Charm components of R using ISR at Belle

  2. R(s) = σ(e+e–→hadrons, s)/ σ(e+e–→μ+μ–, s) Two main reasons to know charm components of R • To shed light on the nature of the charmoniumlike “1–– family” with masses above open charm threshold • To provide model independent information on the parameters of the JPC = 1–– charmonium states spectrum above open charm threshold Galina Pakhlova

  3. Y(4260) Y(4325) Y(4008) Y(4660) Curious 1– –family Galina Pakhlova

  4. e+ e+ e- e– s=E2cm-2EEcm 1– – c c e+e−→ 1– – final states via ISR • ISR physics at B-factories • Quantum numbers of final states are fixed JPC = 1– – • Continuous ISR spectrum: access to the whole s interval • emsuppression compensated by huge luminosity • comparable sensitivity to energy scanning (CLEOc, BES Galina Pakhlova

  5. Two or one states in e+e–→J/π+π–γISR ? arXiv:0808.1543 NEW Y(4260) 344±39 ev Y(4008) 454 fb-1 Br(J/π+π–)Γee , eV Solution1 Y(4008)Solution2 < 0.7 90% CL Solution1 Y(4260)Solution2 7.5±0.9±0.8 Absence of open charm production is inconsistent with conventional charmonium Galina Pakhlova

  6. e+e–→(2S) π+π–γISR Y(4360), Y(4660) ... PRL 98, 212001 (2007) Y(4360)→(2S)ππ Y(4660) ? PRL 99, 142002 (2007) 298 fb-1 Y(4660) 5.8 Y(4360) 8σ 670 fb-1 Y(4360) Y(4360) 2-BW fit with interference Absence of open charm production is inconsistent with conventional charmonium Galina Pakhlova

  7. (4415) (4040) (3770) (4160) Y(4325) Y(4008) Y(4260) Y(4660) Durham Data Base if Ruds=2.285±0.03 Y states vs inclusive cross section e+e–→hadrons • Peak positions forM(J/) & M((2S))significantly different • Y(4008) mass is close to (4040) • Y(4260)mass corresponds to dip ininclusivecross section Galina Pakhlova

  8. Interpretations of Y states Problem: No room for Y states among conventional 1– – charmonium quark model S.Godfrey and N.Isgur PRD32,189 (1985) 33S1= (4040), 23D1 = (4160), 43S1 =(4415) are measured masses of predicted 33D1 (4520),53S1 (4760), 43D1(4810) higher(lower) Y masses Options Y(4325) = 33D1 , Y(4660) = 53S1with shifted masses G.J Ding et al Phys.Rev.D77:014033 (2008) A.M.Badalyan et al arXiv:0805.2291 Charmonium hybrids Zhu S.L.; Close F.E.; Kou E.and Pene O. are expected by LQCD in region 4.2-5 GeV the dominant decay Y(4260)→DD1 (threshold 4287 MeV) Hadro-charmonium Specific charmonium state “coated” by excited light-hadron matter S.Dubinskiy, M.B.Voloshin, A.Gorsky Multiquark states [cq][cq] tetraquark Maiani L., Riquer V., Piccinini F., Polosa A.D. DD1 or D*D0 molecules Swanson E.; Rosner J.L., Close F.E. S-wave charm meson thresholdsLui X. Galina Pakhlova

  9. Charmonium states contribution to inclusive cross sectione+e−→ hadrons above open charm threshold • ψ(3770), ψ(4040), ψ(4160), ψ(4415)have been known for more then 25 years • M,Γtot, Γeeare quite uncertain • To fix the resonance parameters one needs to know their decay channels to take into account their interference: • How to take into account non-resonant contribution? • How to take into account many open charm thresholds? Galina Pakhlova

  10. Phys.Lett.B660,315(2008) Rres=RBW+Rint Resonance shapes Interference term Last fit to the inclusive R spectrum • The interference is taken into account • model dependent • Significant effect of interference To reduce model dependence need to measure exclusive cross sections e+e−→D(*)D(*) Galina Pakhlova

  11. not reconstructed if undetectable  e+ e+ e– s=E2cm-2EEcm reconstructed D D e+e–→DD via ISR with full reconstruction • Full reconstruction of hadronic part • ISR photon detection is not required • but used if it is in the detector acceptance Galina Pakhlova

  12. Phys.Rev.D77,011103(2008) D0D0 DD D+D– 670 fb-1 γISRis not detected • Combinatorial bgs are estimated from D sb • Other bgs are small and taken into account Consistent with ISR production • D0D0or D+D– (full reconstruction) • no extra tracks • detection of γISRis not required • if γISRis detected • M(DDγISR) is required ~ Emc e+e−  DD at s~3.7−5 GeV via ISR γISRis detected Galina Pakhlova

  13. D(*)D(*) e+e– D(*)D(*)cross section calculation • Translate measured mass spectra to cross sections: MeasuredD(*)D(*)mass spectra Total efficiency Differential ISR luminosity Galina Pakhlova

  14. (4040) (4160) 670 fb-1 (3770) (4415) σ(e+e− →DD) σ(ee→D+D−)/σ(ee →D0D0) = 0.72±0.16±0.06 at MDD≈M(3770) is consistent with BES&CLEOc • Broad structure around 3.9 GeV is in qualitative agreement ?? with coupled-channel model Phys.Rev.D21, 203 (1980) • Some structure between (4040) and (4160) • Statistics is small • Hint of (4415) Galina Pakhlova

  15. σ(e+e− →DD) Phys.Rev.D77,011103(2008) Phys.Rev. D76, 111105(2007) arXiv:0801.3418 Durham Data Base Galina Pakhlova

  16. e+ e+ reconstructed D(*) e– s=E2cm-2EEcm π D* D not reconstructed but constrained e+e–→D(*)D* via ISR with partial reconstruction DD* & D*D* • D* partial reconstruction • increase eff ~ 10-20 times • detection of ISR photon Galina Pakhlova

  17. e+e–→D(*)D* with partial reconstruction Phys. Rev. Lett. 98, 092001 (2007) D+D*- D*+D*- MD* MD* Mrec(D*+γISR) Mrec(D*+γISR) ΔMrec ΔMrec • Reconstruction of D(*)γISR • wide peak inMrec(D(*)γISR)atM D* • contribution from e+e–→D(*)D* (n)πγ • Reconstruction of D(*) γISR+πslowfrom unreconstructed D* • wide peak inMrec(D(*)π-γISR)atMD • Use recoil mass difference Mrec = Mrec(D(*)γISR) - Mrec(D(*)πγISR) • narrow peak at(MD* - MD) • cancellation of momentum smearing • Tight ΔMrec cut small background • Use kinematical constraint Mrecoil(D(*)γISR) →MD* to improve resolution with ΔMrec cut σRMD~1 MeV Galina Pakhlova

  18. Exclusive e+e–→D(*)D*cross-sections arXiv:0801.3418 Phys. Rev. Lett. 98, 092001 (2007) D*+D*- (4040) (4415) (4160) (4040) (4160) Y(4260) D+D*- (4160) (4040) 550/fb Backgrounds are reliably estimated from the data Y(4260) signal DD* : hint, but not significant D*D* : clear dip (similar to inclusive R) • Systematic errors ≈ statistical errors Durham Data Base Galina Pakhlova

  19. not reconstructed if undetectable  e+ e+ e– s=E2cm-2EEcm D reconstructed D π Three body final states D0 D− + • full reconstruction of hadronic part • ISR photon detection is not required • but used if it is in the detector acceptance Galina Pakhlova

  20. 670 fb-1 Consistent with ISR production e+e− D0D–+ at s ~ 4−5 GeV via ISR D0 D− π+ • full reconstruction • no extra tracks Clear (4415)DD signal • similar analysis and bgs • no major bgs except for combinatorial Galina Pakhlova

  21. Phys.Rev.Lett.100,062001(2008) 670 fb-1 DD*2(2460) ~10σ M = 4411± 7 MeV Γtot =77±20 MeV Nev= 109± 25 DDπ non DD*2(2460) Consistent with BES, Phys.Lett.B660,315(2008) PDG06, Barnes at.al Phys. Rev. D72, 054026 (2005) Resonant structure in (4415)DD • M(D0π+) vs M(D–π+) from (4415) region • Clear D*2(2460) signals • Constructive interference • No non-D*2(2460) contribution Br((4415)  D(D)non D2(2460))/Br((4415) DD*2(2460))<0.22 σ(e+e–→(4415))×Br((4415)→DD*2(2460))×Br(D*2(2460) →Dπ)=(0.74±0.17±0.07)nb Galina Pakhlova

  22. e+ e+ reconstructed Λc+ e– s=E2cm-2EEcm p tag p ─ ─ Λc– X not reconstructed Partial reconstruction with anti-proton tag Charm baryons final states Reconstruct Λc+ • anti-proton tagfrom inclusive Λc–→p–XBr(Λc+→pX) = (50±16)% • combinatorial background suppressed by a factor of 10 • detect the high energy ISR photon Galina Pakhlova

  23. e+e–→Λc+Λc–γISR partial reconstruction with p tag ─ no Σ– Λc– Λc–(2765) Λc–(2880) Λc–(2595) Λc–(2625) Λc sidebands Mrecoil(Λc+γISR) • Clear peak in Mrec(Λc+ISR ) distribution at Λc mass. • Wide shoulder for mass >2.5GeV/c2 • contributions from Λc+Λc–π0 • could proceed via Λc+Σ– ;violates isospin and should be highly suppressed • andΛc+Λc–ππ • could proceed via Λc+Λc(2595)–, Λc+Λc(2625)–, Λc+Λc(2765)–, Λc+Λc(2880)– • Apply asymmetric requirement on Mrec(Λc+ISR ) to suppress tail from Λc+Λc–π0 and Λc+Λc–ππ reflection • Total refection contributions < 5% (included in systematics) • Use kinematical constraint Mrecoil(ΛcISR)  M Λc to improve resolution • Look atMrecoil(ISR) ≡Mass spectra ofΛc+Λc– Galina Pakhlova

  24. Phys.Rev.Lett.101,172001(2008) e+e–→Λc+Λc–γISR • no peak-like structure X(4630) 8.2 NEW 670 fb-1 • dibaryon threshold effect • like in B→pΛπ, J/→γpp • X(4630) = Y(4660)? JPC=1–– e+e–→Λc+Λc–γISR Interpretations for the new X(4630) • 53S1 charmonium state • in some models M (53S1) ~4670MeV • Something else... Galina Pakhlova

  25. D*D* DD* DD DDπ Λc+Λc– Contribution to the inclusive cross section Galina Pakhlova

  26. σ(e+e–→open charm) via ISR PRD77,011103(2008) DD ? DD* (4160) Y(4360) PRL98, 092001 (2007) Belle:Sum of all measured exclusive contributions Y(4008) D*D* Y(4260) (4415) (4040) (3770) (4160) Y(4008) Y(4360) PRL100,062001(2008) (4415) Y(4660) DDπ Y(4260) Y(4660) Phys.Rev.Lett.101,172001(2008) (4040) Λc+Λc– NEW Durham Data Base if Ruds=2.285±0.03 Y states vs exclusive cross sections • Y(4008) mass coincides with DD* peak • Y(4260)mass corresponds to dip inD*D* X-sect. • Y(4660) mass is close to Λc+Λc–peak • Enhancement near 3.9 GeV in ee→DDcoupled channel effect? (4415) more contributions to be measure Galina Pakhlova

  27. In conclusion Five exclusive open charm final states were measured DD, DDπ, D*D, D*D*, ΛcΛc • Their sum is close to e+e– → hadrons • Belle & BaBar &Cleo_c cross sections measurements are consistent with each other in corresponding energy ranges • D*D*(main contribution) • complicated shape of cross section • clear dip at M(D*D*) ~ 4260GeV (similar to inclusive R) • DD*(main contribution) • broad peak at threshold (shifted relative to 4040 GeV) • DD • complicated shape of cross section • broad enhancement ~ 3.9 GeV – coupled channel effect? • DDπ • (4415) signal observed, dominated by (4415)→DD2(2460) • ΛcΛc • Enhancement at threshold, mass and width are consistent with Y(4660) Galina Pakhlova

  28. In conclusion All presented cross sections could be found in Durham Data Base Theoretical efforts to describe charm components of R are kindly requested! Galina Pakhlova

  29. To do list Galina Pakhlova

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