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Observation of a State at 2463 MeV Decaying to D s * p 0 , and

Observation of a State at 2463 MeV Decaying to D s * p 0 , and Confirmation of D sJ *(2317) at CLEO Jon Urheim, U. of Minnesota CIPANP 2003, 20 May 2003. Study of D s p 0 and D s * p 0 final states Investigations of other possible final states

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Observation of a State at 2463 MeV Decaying to D s * p 0 , and

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  1. Observation of a State at 2463 MeV Decaying to Ds* p0, and Confirmation of DsJ*(2317) at CLEO Jon Urheim, U. of Minnesota CIPANP 2003, 20 May 2003 • Study of Dsp0 and Ds* p0 final states • Investigations of other possible final states • results as reported in CLEO Conf 03-01, hep-ex/0305017 • special acknowledgements to: Selina Li, JC Wang and also to: Dave Cinabro, Sheldon Stone

  2. Initial Look at DsJ*(2317)  Dsp0 Started out trying to confirm BaBar signal, and measure properties of this state  use 13.5 /fb from CLEO II / II.V ( ~ 15 % of BaBar sample)  use simple cuts, similar to those used in BaBar analysis  huge signal: 231 +/- 30 evts  width of Gaussian 8.4 +/- 1.3 MeV exp. resolution: 6.4 +/- 0.4 MeV  generic e+e-  qq Monte Carlo describes combinatoric background perfectly !

  3. Second Look: Dsp0 and Ds*p0 2.32 GeV Now: more restrictive selection of photons to reduce comb. backgrounds.  Signals in both channels, at nearly the same value of DM  Dsp0 mode: signal remains robust  Ds* p0 mode: 53.3 +/- 9.7 events, width matches resol’n (~ 6.5 MeV) BaBar also saw a peak here 1+ partner of 0+ DsJ*(2317) ?  are these two separate particles? 2.11 GeV Dsp0 2.46 GeV 2.32 GeV Ds* p0

  4. Possible ambiguity: Feed-down: state at 2463  Ds* p0 will generate peak at 2317 if photon unseen or ignored ! (but note that peak is smeared) Feed-up: state at 2317  Ds p0 will generate peak at 2463 if random photon makes Ds* ! (but note that peak is smeared) We try to address this in three ways: Monte Carlo simulations  use as basis for ‘unfold’ Use sidebands from the data to estimate background Study lineshapes of peaks Are there really two states ?

  5. Feed down and Feed up All possible p0 and g transitions DsJ* (2463) g DsJ* (2317) p0 p0 Ds* (2112) g Ds (1969) fp

  6. Feed down and Feed up Assume unseen g transitions small DsJ* (2463) DsJ* (2317) p0 p0 Ds* (2112) g Ds (1969) fp

  7. Feed down and Feed up case of no DsJ*(2317) (feed down) DsJ* (2463) DsJ* (2317) p0 Ds* (2112) g Ds (1969) fp

  8. Feed down and Feed up case of no DsJ*(2463) (feed up) DsJ* (2463) DsJ* (2317) p0 random Ds* (2112) g Ds (1969) fp

  9. Possible ambiguity: Feed-down: state at 2463  Ds* p0 will generate peak at 2317 if photon unseen or ignored ! (but note that peak is smeared) Feed-up: state at 2317  Ds p0 will generate peak at 2463 if random photon makes Ds* ! (but note that peak is smeared) We try to address this in three ways: Monte Carlo simulations  use as basis for ‘unfold’ Use sidebands from the data to estimate background Study lineshapes of peaks Are there really two states ?

  10. Feed up:MC Simulations Ds* (2463) Ds* p0 Signal MC Ds* (2317) Dsp0 + Random g s= 6.6 ± 0.5 MeV s= 14.9 ± 0.6 MeV • Feed-up prob is small (9%) & well modeled by MC • Feed-down effect is larger (but easier to model), and also results in similar smearing

  11. Feed up: Ds* Sidebands 2.46 GeV If there is a state at 2317 that decays to Ds p0, and can pick up random photons to mimic Ds* p0, then there should still be a peak when photons are selected that don’t form a Ds* !  Look in sidebands  Only a small excess of events in the 2463 signal region from the Ds* sidebands !  Will make this quantitative in following slide Ds* signal region Ds* side- bands

  12. Observation of DsJ*(2463) Two methods of determining feed-up from 2317 into 2463:  Use Monte Carlo-based unfolding method  Fit to Ds*-sideband subtracted DM dist’n for data Statistical signficance ~ 5.3s To check feed-down from 2463  2317  Use MC-based unfolding method  Fit Ds p0 DMto two Gaussians: wide Gaussian measures feed-down, narrow one for signal.  Two methods are consistent. ~22% of evts are feed-down

  13. Searches for other decays Limits for DsJ*(2317) decay @ 90 % CL Yield MC Effcy (%) Limit Prediction • Theory prediction for Ds*g by Bardeen, Eichten and Hill • Working on limits for DsJ*(2463) decay… **After correction for feed-down from DsJ*(2463)

  14. Observation of two states by CLEO: DsJ*(2463): decaying to Ds* p0, as expected for JP= 1+  Evidence is strong enough to claim this state exists ! DsJ*(2317): decaying to Ds p0, as expected for JP = 0+  Confirms BaBar discovery of this state Studies: Masses: [preliminary] M[DsJ*(2317)] – M[Ds] = 350.4 +/- 1.2 +/- 1.0 MeV M[DsJ*(2463)] – M[Ds*] = 351.6 +/- 1.7 +/- 1.0 MeV Widths -- [preliminary] G < 7 MeV, for both states Decays -- no other decays seen, yet… Results are compatible w/ models based on HQET and chiral symmetry, that predict 1+ & 0+ are the chiral partners of the 1- & 0- states, with same mass splitting (Bardeen et al) Summary & Conclusions

  15. Calc’n of BG-subtracted yields R0  reconstructed DsJ*(2317)Dsp0 excluding feed-down. R1  reconstructed DsJ*(2463)Ds*p0excluding feed-up. N0 # of events from fit to Dsp0 mass spectrum (DATA)160.2  18.5 N1 # of events from fit to Ds*p0 mass spectrum(DATA)53.3  9.7 F1 prob for a DsJ*(2463) w/ reconstructed Dsp0 to f/d divided by photon finding effcy (MC) 0.840 ± 0.044 F0prob. that a Ds picks up a random gto form Ds* (MC) 0.091 ± 0.007 N0 = R0 + f/d = R0 + R1 x f1 N1 = R1 + f/u = R1 + R0 x f0 R0 = 124.9  22.5 R1 = 41.9 10.7

  16. Fits to Dsp0 Mass Diff. Dist’n Fit to Single Gaussian + bg 231 +/- 30 events s = 8.4 ± 1.3 MeV Fit to Two Gaussians + bg 144 +/- 36 / 125 +/- 50 evts s = 6.4(fixed)/ 16 ± 5 MeV

  17. Search for DsJ*(xxxx)  Dsp+p-

  18. Search for DsJ*(xxxx)  Ds(*) g

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