1 / 30

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

ankti
Télécharger la présentation

Update on X(3872) J PC determination

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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)

More Related