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Charmed Hadron Spectroscopy At

Charmed Hadron Spectroscopy At. Introduction D ** D S ** S C , S C * L C *. Robert K. Kutschke Fermilab FCP01 March 7, 2001. At Fermilab g BeO charm. g. FOCUS: The Successor to E687. Segmented BeO Target interleaved with SMDs. Upgraded: EM Calorimetry. Cerenkov system.

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Charmed Hadron Spectroscopy At

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  1. Charmed Hadron Spectroscopy At • Introduction • D** • DS** • SC , SC* • LC* Robert K. Kutschke Fermilab FCP01 March 7, 2001

  2. At Fermilab g BeO charm g Frontiers in Contemporary Physics, 2001.

  3. FOCUS: The Successor to E687 • Segmented BeO Target interleaved with SMDs. • Upgraded: • EM Calorimetry. • Cerenkov system. • Muon ID capability. • Data taken in 1996-1997. • More than 10 times the Luminosity • >106 reconstructed “Golden Mode” Decays: D0K-p+, K-p+p-p+and D+K-p+p+. Frontiers in Contemporary Physics, 2001.

  4. Candidate Driven Vertexing • Find charm candidate: good vertex, good particle ID. • Seed primary vertex finder with the charm candidate. • Require isolated secondary. One measure: L/sL> cut. • Add tracks from primary to form Lc p combinations. Frontiers in Contemporary Physics, 2001.

  5. - - - - - - u,d,s u,d,s P-wave Charmed Mesons • L=1 between c and light quark ( q=u,d,s ). • jlight = Slight + L , approximately good Q number if mC >> LQCD Rosner: “the hydrogen atom of QCD” • Idealized picture is a “doublet of doublets”. • Strong decays to D(*)p ( or D(*)K for DS ) c D*, D - c q q p, r, (K, K*) Frontiers in Contemporary Physics, 2001.

  6. JP 2+ 1+ 1+ 0+ Decays D*, D D* D* D G(MeV/c2) 20 >100 Observed? D2*+, D2*0, Ds2* D1+, D10, Ds1 No confirmed candidates mc>>QCD jlight mc No spins 3/2 1/2 Idealized Picture of P-wave Charmed Mesons Heavy quark symmetry: jl=3/2 dominant decays are D-wave jl=1/2 dominant decays are S-wave Reminder: D: JP = 0- D*: JP = 1- JlightP =1/2- Frontiers in Contemporary Physics, 2001.

  7. Angular Momentum and Parity Selection Rules 1+3/2 Decays via D-wave 1+1/2 Decays via S-wave All 5 decays in the multiplet are described by 2 parameters, the S wave and D wave amplitudes (x Wigner 6-j, x phase space) Frontiers in Contemporary Physics, 2001.

  8. What’s Overly Simplified in the Ideal Picture? • Doublets may overlap ( which 1+ is more massive?) • Is suppression of S wave widths complete? • Ds1 right at threshold for D*K: • Very narrow, G < 2.3 MeV/c2 @ 90% CL. • Data suggests mostly S-wave! Frontiers in Contemporary Physics, 2001.

  9. S-Wave Charm States at FOCUS D0 K-p+ D0 D+ D0 K-p+ p+ p- Entries / 5 MeV/c2 D+ K-p+ p+ For S/B > 7, > 330,000 D candidates (GeV/c2) M(Kp or K3p) M(Kpp) D*+ D0p+ D*+ 30000 K-p+ 20000 K- p+ p+ p+ Entries / 0.5 MeV/c2 10000 For S/B > 5,  70,000 D*+ candidates 0.140 0.144 0.148 (GeV/c2) M(D0p+)-M(D0) Frontiers in Contemporary Physics, 2001.

  10. D0p+and D+p- Mass Distributions Feed down from D2*, D1 partial reconstruction Feed down from D2*, D1 partial reconstruction Entries / 10 MeV/c2 Entries / 10 MeV/c2 FOCUS FOCUS Wrong sign Wrong sign M(D0p+)-M(D0)+1.8646 (GeV/c2) M(D+p-)-M(D+)+1.8693 (GeV/c2) [ Shorthand: MF(D0p+) MF(D+p-) ] Frontiers in Contemporary Physics, 2001.

  11. D*op+ D1 + *+ Dopo ,Dog D*op+ D2 Dopo ,Dog 400 600 Entries / 10 MeV/c2 Entries / 10 MeV/c2 300 400 200 200 100 2.0 2.0 2.2 2.2 2.4 2.4 2.6 2.6 2.8 2.8 3.0 3.0 MF(D0p+) (GeV/c2) MF(D0p+) (GeV/c2) Get Feed-down Line Shapes from Monte Carlo MC MC Frontiers in Contemporary Physics, 2001.

  12. Beyond Signal Region all Shapes are Exponential D2*0 D+- D2*+ Do+ Right sign: e-2.530.01 Right sign: e-2.350.01 Entries / 10 MeV/c2 Entries / 10 MeV/c2 Wrong sign: e-2.270.01 Wrong sign: e-2.380.01 Side band: e-2.670.04 Side band: e-2.650.03 MF(D0p+) (GeV/c2) MF(D+p-) (GeV/c2) Frontiers in Contemporary Physics, 2001.

  13. Fitting the D0p+ MassDistribution (1) Fit Results: Terms in the Fit: c2 / dof= 3.1 • Signal: D-wave Rel. BW, convoluted with a gaussian, s = 7 MeV/c2. • Exponential extrapolated from 2.4 – 4.5 GeV/c2. • MC D1 Feed-down. • MC D2 Feed-down Entries / 10 MeV/c2 G=724 MeV/c2 FOCUS Get horrible fit! MF(D0p+) (GeV/c2) ( GPDG(D2*+) = 25  8 MeV/c2 ) Frontiers in Contemporary Physics, 2001.

  14. Fitting the D0p+ MassDistribution (2) Fit Results: M=2468.21.5 MeV/c2 c2 / dof= 3.1 G= 28.6±1.3 MeV/c2 Entries / 10 MeV/c2 c2 / dof= 1.8 G=724 MeV/c2 FOCUS FOCUS MF(D0p+) (GeV/c2) MF(D0p+) (GeV/c2) Add 5th term to the fit: S-wave Rel. BW Frontiers in Contemporary Physics, 2001.

  15. D*+ Dop+ *+ D2  Do+ Pion momentum (GeV/c) Reducing BG from Soft p+ From D*+ Decays M = 2468.5  2.1 MeV/c2 G = 30.3  3.6 MeV/c2 Entries / 10 MeV/c2 MC D2*+ FOCUS pp > 10 GeV/c MC MF(D0p+) (GeV/c2) Frontiers in Contemporary Physics, 2001.

  16. Fitting the D+p- MassDistribution c2 / dof = 0.9 GPDG ( D2*0 ) = 23  5MeV/c2 M = 2463.5  1.5 MeV/c2 c2 / dof= 2 G =30.5  1.9 MeV/c2 Entries / 10 MeV/c2 Entries / 10 MeV/c2 G = 55  3 MeV/c2 FOCUS FOCUS MF(D+p-) (GeV/c2) MF(D+p-) (GeV/c2) Signal + Exp + D1 + D2 + S-Wave Rel. BW Frontiers in Contemporary Physics, 2001.

  17. Pp < 18 GeV/c Pp > 18 GeV/c Pp < 18 GeV/c Pp > 18 GeV/c PD> 70 GeV/c PD< 70 GeV/c PD< 70 GeV/c PD> 70 GeV/c Antiparticle Antiparticle L/s < 30 L/s > 30 Particle L/s > 30 L/s < 30 Particle D2* Mass and Width Systematics D2*+Mass D2*+Width D2*+ Mass MeV/c2 D2*+ Width MeV/c2 FOCUS D2* Results Mass (MeV/c2) G (MeV/c2) D2*+ 2468.2  1.5  1.428.6  1.3  3.8 D2*0 2463.5  1.5  1.530.5  1.9  3.8 Preliminary PDG 2000: M+=24594, M0=2458.92.0, G+=258, G0=235 MeV/c2. Frontiers in Contemporary Physics, 2001.

  18. D*+p- Mass Distribution D10 Yield = 889  92 D2*0 Yield = 977  101 1200 Entries / 10 MeV/c2 800 Preliminary 600 400 200 Wrong sign 2.1 2.4 2.7 2.7 (GeV/c2) M((D0p+)p-)-M(D0p+)+2.0100 [ Shorthand: MF(D*+p-)] Frontiers in Contemporary Physics, 2001.

  19. c D*, D - c q DS** - u q K, K* - u Observation of the DS2* and DS1 DS2* D0 K+  D+ KS0 DS1 D*+ KS0 D*+ D0 + D0 K-+, K- ++- D+ K-++ Frontiers in Contemporary Physics, 2001.

  20. Observation of the Ds2* at Focus D0K+ D+KS0 First observation of the D+KS0 mode! FOCUS Preliminary There are some real KS0 in the sideband sample. Frontiers in Contemporary Physics, 2001.

  21. Simultaneous Fits to D0K+ and D+KS0 Spectra Preliminary Terms in the fit: • DS2 Signal: D-wave Rel. BW • Smooth background shape • MC DS1 feeddown shape • MC DS2 feeddown shape. Significance is not stable with cut variations! • Simultaneous: M and G same. • Errors are statistical only PDG: M = 2573.5 ± 1.7 MeV/c2 G = 15 ± 5 MeV/c2 First observation of D+KS0 mode Frontiers in Contemporary Physics, 2001.

  22. Observation of the DS1 at FOCUS Terms in the fit: Preliminary • DS1 Signal: Non Rel BW, convoluted with a gaussian. • Smooth background shape. • DS2* Signal: D-wave Rel BW. • Errors are statistical only PDG: D = 525.35 ± 0.34 MeV/c2 G < 2.3 MeV/c2 @ 90 % CL. M(D*+Ks0)-M(D*+) Frontiers in Contemporary Physics, 2001.

  23. Definition: L: I=0 S: I=1 Some Charmed Baryons: cud JP 3/2- Lc(2625) cdd cud cuu JP Lc(2593) 1/2- Sc*0 Sc*+ Sc*++ 3/2+ Sc0 Sc+ Sc++ 1/2+ Lc*Lc p p Lc*Lc p Sc(*)Lc p Lc+ P-Wave Baryon Frontiers in Contemporary Physics, 2001.

  24. Lc+ p+ K-p+ • L/sL > 6. • Isolated secondary vertex. • affirmative Id for p and K • consistency for p • For Sc+study • L/s > 4, Looser . • Yield = 18346 248 • S/B = 1.19 Č Č Č ± Selection of Lcfor Sc++and Sc0Studies Yield=12410  180 5000 • =7.890.11 MeV/c2 Entries / 5 MeV/c2 4000 S/B = 1.7 FOCUS Cut  2s 3000 Sidebands 2000 1000 2.4 2.2 2.1 2.3 (GeV/c2) M(p+K-p+) Frontiers in Contemporary Physics, 2001.

  25. Sc++and Sc0Masses Yield = 362  36 M(Sc0) – M(Lc+) = 167.38  0.21 MeV/c2 SC0 LC+ p- 60 40 ( CLEO 2.5 ICHEP 2000 20 167.20.10.2 MeV/c2 ) Entries / 500 KeV/c2 0.17 0.19 0.15 (GeV/c2) SC++ LC+ p+ Yield = 461  39 M(Sc++) – M(Lc+) = 167.35  0.19 MeV/c2 60 FOCUS 40 20 ( CLEO 2.5 ICHEP 2000 167.40.10.2 MeV/c2 ) 0.19 0.17 0.15 (GeV/c2) M(LC+p) – M(LC+) Frontiers in Contemporary Physics, 2001.

  26. Systematic Errors M(Sc0) – M(Lc+) = 167.38  0.21  0.13 MeV/c2 M(Sc ) – M(Lc ) = 167.35 0.19  0.12 MeV/c2 M(Sc++) – M(Sc0) =-0.03  0.28  0.11 MeV/c2 • Phys. Lett. B488, 218-224, 2000. Frontiers in Contemporary Physics, 2001.

  27. Frontiers in Contemporary Physics, 2001.

  28. Observation of Sc+ Lc+ p0 p0 gg Reconstructed in EMCAL. 80 200 N / 3 MeV/c2 N / 1 MeV/c2 60 150 40 100 ± Yield =118 40 s = 50 20 FOCUS 3.040.84 MeV/c2 0.2 0.3 0.4 0.16 0.20 0.14 0.18 (GeV/c2) M(Lc+ p0) – M(Lc+) Preliminary ± ± M(Sc+) –M(Lc+) = 168.0 1.0 0.3 MeV/c2 ± ± M(Sc+) –M(Sc0) = 0.6 1.0 0.3 MeV/c2 ( CLEO hep_ex/0007041: M(Sc+) – M(Lc+) = 166.4 0.2 0.3 MeV/c2 ) ± ± Frontiers in Contemporary Physics, 2001.

  29. Isospin Mass Differences Preliminary Theory has canceling contributions: quark masses, strong potential, Coulomb interaction, hyperfine ( EM + QCD ). Frontiers in Contemporary Physics, 2001.

  30. +0.51 +0.51 -0.55 -0.56 Natural Widths (MeV/c2) Signal Shape: BW convoluted with a gaussian. FOCUS 80 80 Preliminary Entries / 0.5 MeV/c2 60 60 40 40 20 20 s++ = 1.49 0.02 MeV/c2 s0 = 1.48 0.01 MeV/c2 0.14 0.16 0.18 0.20 0.14 0.16 0.18 0.20 M(Lc+ p-) – M(Lc) M(Lc+ p+) – M(Lc) (GeV/c2) G(Sc0) = 2.58  0.79 G(Sc++) = 2.53  0.77 ( CLEO 2.5 ICHEP 2000: G0 = 2.40.2 0.4 G++ = 2.50.20.4 MeV/c2 ) Frontiers in Contemporary Physics, 2001.

  31. G(Sc++) and G(Sc0) +0.51 +0.51 -0.55 -0.56 Frontiers in Contemporary Physics, 2001.

  32. Observation of Sc*++ and Sc*0 Preliminary ± ± Yield = 593 146 Yield = 1284 225 Stat errs only 300 300 FOCUS Entries / 1.0 MeV/c2 200 200 100 100 G = 9.4  3.7 MeV/c2 G = 23.6  4.5 MeV/c2 0.15 0.20 0.25 0.30 0.15 0.20 0.25 0.30 M(Lc+p-) – M(Lc) M(Lc+p+) – M(Lc) (GeV/c2) DM(Sc0) = 232.7  1.2 MeV/c2 DM(Sc++) = 234.21.5 MeV/c2 M(Sc*0) - M(Sc*++) = -1.5  1.9 MeV/c2 ( CLEO II: DM0=232.61.00.8 G0=13.03.74.0 DM++=234.51.10.8 G++=17.93.84.0 ) Frontiers in Contemporary Physics, 2001.

  33. Observation of Excited Lc States Lc(2625): DM = 341.6 ± 0.3 MeV/c2 250 Entries / 2 MeV/c2 Preliminary ( PDG 2000: 341.7  0.6 ) 200 Yield = 371 ± 32 150 Lc(2593): DM = 308.1 ± 0.7 MeV/c2 100 50 FOCUS ( PDG 2000: 308.9  0.6 ) Yield = 100 ± 20 0.30 0.35 0.40 0.45 Errors are Stat only. (GeV/c2) M(Lc+p+p-) – M(Lc+) Frontiers in Contemporary Physics, 2001.

  34. Summary and Conclusions • Preliminary masses and widths in D** and DS** sectors. • First observation of DS2* D+KS0. • Confronting a new level of systematics in the D** sector • We require something like the expected broad state to fit the mass difference spectrum successfully. • Measurements of SC++ and SC0 Masses and Widths • Published: M(Sc++) – M(Sc0) =-0.03  0.28  0.11 MeV/c2 • Confirm SC+, SC*++, SC*0 previously seen only by CLEO II. • A good start onLC* Frontiers in Contemporary Physics, 2001.

  35. References for Theory on Page 30 • M.A. Ivanov et al., Phys. Lett. B442, 435 (1998). • M.A. Ivanov et al., Phys. Rev. D60, 094002 (1999). • S. Tawfig et al., Phys. Rev. D58, 054010 (1998). • M.-Q. Huang et al., Phys. Rev. D52, 3986 (1995). • D. Pirol and T.-M. Yan, Phys. Rev D56, 5483 (1997). • J.L. Rosner, Phys. Rev. D52, 6461 (1995). Frontiers in Contemporary Physics, 2001.

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