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Update on X(3872) J PC determination

Update on X(3872) J PC determination. Soo-Kyung Choi Stephen L. Olsen Gyeongsang Univ. Univ. of Hawai’i. In Japan & Korea; not in Hawai’i. April Fool’s day 2005 Quarkonium group meeting. Possible J PC values (for J ≤ 2). Use 250 fb -1  ~275M BB prs. Signal

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Update on X(3872) J PC determination

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  1. Update on X(3872) JPC determination Soo-Kyung Choi Stephen L. Olsen Gyeongsang Univ. Univ. of Hawai’i In Japan & Korea; not in Hawai’i April Fool’s day 2005 Quarkonium group meeting

  2. Possible JPC values (for J ≤ 2)

  3. Use 250 fb-1  ~275M BB prs Signal (47 ev) Sidebands (114/10 = 11.4 ev)

  4. Changes since BAM • Use this value for c2 • recommended by PDG • (& Golob) for low statistics • measurements L= PDG Eq32.12 l(q) is the likelihood ratio: • Use MC-generated • histograms. Use EvtGen • to generate different JPC • scenarios. (Thanks to help • from Ishikawa-san.)

  5. Product Branching Fraction Use PDG for y’

  6. Areas of investigation • Search for radiative decays • Angular correlations in XppJ/y decays • Fits to the M(pp) distribution

  7. Search for X(3872)g J/y

  8. Select BK J/yg(include both K± & Ks) • Tight J/y cuts • K± id>0.5 / Belle-standard “good Ks” • Eg>40 MeV • p0 veto (c2>4.0) • K* veto (M(Kg)>1.0 GeV) • R2<0.4; |cosqB| < 0.8 • |Mbc – 5.28|<0.0055 GeV (2s) • |DE|<0.034 GeV (2s) • E7  E37

  9. Select BKg J/y BKcc1; cc1g J/y Fit to Mbc & DE use MC to scale parameters to the X(3872) M(gJ/y)

  10. Look in X(3872) region X(3872)? Look here M(gJ/y) 13.6 ± 4.4 events @ 3872 MeV (5.7s significance)

  11. Clear signal in DE as well

  12. M(g J/y) around 3872 MeV M(gJ/y) “look-back” plot Bkgd level @ 3872 MeV: 2.6 ± 0.6 evts Prob 3.1evts 13.6 evts <2x10-5

  13. Br(Xg J/y) MC:0.19±0.01

  14. Evidence for X(3872)p+p-p0 J/y(reported last summer hep-ex/0408116) 12.4 ± 4.2 evts B-meson yields vs M(p+p-p0)

  15. Evidence for C=+1is now overwhelming • Bg J/y only allowed for C=+1 • same for B”w”J/y (reported earlier) • M(pp) for Xp+p-J/y looks like a r

  16. Possible JPC values (for J ≤ 2)

  17. Angular Correlations

  18. Strategy: for each JPC, find a distrib 0if we see any events there, we can rule it out example1--: sin2qKm y’is 1-- Use y’ as a check. qKm c2/dof = 16.3/9 K compute angles in J/y restframe |cos qKm| D.V. Bugg hep-ph/0410168v2

  19. |cosqKl| for X(3872) events Signal MC + bkgd see 8 evts/bin c2/dof = 45/9 expect 2~3evts/bin background scaled from sidebands X(3872) is not 1-- !

  20. 1+- and 2-- use J/y helicity angle qJ/y c2/dof = 32/9 1+- K X qJ/y c2/dof = 20/9 2-- J/y |cosqJ/y| rule out 1+-

  21. 0-+Rosner(PRD 70 094023) 0-+ : sin2q sin2y c2/dof=18/9 q |cosq| y c2/dof=34/9 safe to rule out 0-+ |cosy|

  22. 0 ++Rosner(PRD 70 094023) again In the limit where X(3872), pp, & J/y rest frames coincide: dG/dcosqlp sin2qlp qlp c2/dof = 30/9 c2/dof = 41/9 rule out 0++ |cosqlp|

  23. 1++ 1++: sin2ql sin2c Rosner (PRD 70 094023) c2/dof = 10/9 ql K |cosql| c c2/dof = 13/9 1++ looks okay! |cosc|

  24. Possible JPC values (for J ≤ 2)

  25. Fits to the M(pp)Distribution J/y XrJ/y in P-wave has a q*3 centrifugal barrier q* X r q*

  26. Acceptance vs M(p+p-)

  27. M(pp) can distinguish r-J/y S- & P-waves P-wave: c2/dof = 71/39 S-wave: c2/dof = 43/39 (CL=0.1%) (CL= 28%) q* roll-off q*3 roll-off Shape of M(pp) distribution near the kinematic limit favors S-wave

  28. Possible JPC values (for J ≤ 2)

  29. Summary • Rule out all possibilities except: • 1++ • Nicely passes all tests • 2++ • Not seriously challenged by this anaysis • BK (2++) should be suppressed • 2++  DD is allowed, should be wide • this is ruled out by Garima et al & Jolanta et al observation of X DD* Important result! Needs to be made public

  30. Could the X(3872) be the cc1’? • Mass is off: theory range 39563990 MeV • G(gJ/y)/G(ppJ/y) = 0.14 ± 0.05 is too small • Naïve expectation for cc1’ is ~ 40 or higher • (cc1’ppJ/y violates isospin) For more details about the results reported here see Belle Note 800 (ver.2 posted today)

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