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

Possible J PC values (for J ≤ 2) 0 -- exotic violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) 2- -(2)2- -(2) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed

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

Changes since BAM L=L= (  ) is the likelihood ratio: Use this value for  2 recommended by PDG (& Golob) for low statistics measurements Use MC-generated histograms. Use EvtGen to generate different J PC scenarios. (Thanks to help from Ishikawa-san.) PDG Eq32.12

Product Branching Fraction Use PDG for  ’

Areas of investigation Search for radiative decays Angular correlations in X   J/  decays Fits to the M(  ) distribution

Search for X(3872)   J/ 

Select B  K J/   (include both K ± & K s ) Tight J/  cuts K ± id>0.5 / Belle-standard “good Ks” E  >40 MeV  0 veto (  2 >4.0) K* veto (M(K  )>1.0 GeV) R 2 <0.4; |cos  B | < 0.8 |M bc – 5.28|< GeV (2  ) |  E|<0.034 GeV (2  ) E7  E37

Select B  K  J/  B  K  c1 ;  c1   J/  M(  J/  ) Fit to M bc &  E use MC to scale parameters to the X(3872)

X(3872)? Look here M(  J/  ) 13.6 ± MeV (5.7  significance) Look in X(3872) region

Clear signal in  E as well

M(  J/  ) around 3872 MeV Bkgd 3872 MeV: 2.6 ± 0.6 evts Prob 3.1evts  13.6 evts <2x10 -5 M(  J/  ) “look-back” plot

Br(X   J/  ) MC:0.19±0.01

Evidence for X(3872)        J/   reported last summer hep-ex/ ) 12.4 ± 4.2 evts B-meson yields vs M(       )

Evidence for C=+1 is now overwhelming B   J/  only allowed for C=+1 same for B  ”  ”J/  (reported earlier) M(  ) for X      J/  looks like a 

Possible J PC values (for J ≤ 2) 0 -- exotic violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) (  2 ) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed

Angular Correlations

Strategy: for each J PC, find a distrib  0 if we see any events there, we can rule it out  example 1 -- : sin 2  K  K compute angles in J/  restframe D.V. Bugg hep-ph/ v2 Use  ’ as a check.  ’ is 1 -- |cos   |  2 /dof = 16.3/9

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

1 +- and 2 -- use J/  helicity angle  J/  K X J/   J/  |cos  J/  |  2 /dof = 32/9  2 /dof = 20/9 rule out 1 +-

0 -+ Rosner (PRD ) 0 -+ : sin 2  sin 2  safe to rule out 0 -+    2 /dof=18/9 |cos  | |cos  |  2 /dof=34/9

0 ++ Rosner (PRD ) again ll rule out 0 ++ |cos  l  | In the limit where X(3872), , & J/  rest frames coincide: d  /dcos  l   sin 2  l   2 /dof = 41/9  2 /dof = 30/9

1 ++ ll  1 ++ : sin 2  l sin 2  K 1 ++ looks okay! Rosner (PRD ) |cos  l | |cos  |  2 /dof = 13/9  2 /dof = 10/9

Possible J PC values (for J ≤ 2) 0 -- exotic violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) (  2 ) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed

Fits to the M(  ) Distribution X   J/  in P-wave has a q* 3 centrifugal barrier X J/   q*

Acceptance vs M(     )

M(  ) can distinguish  -J/  S- & P-waves S-wave:  2 / dof = 43/39 q* roll-off (CL= 28%) Shape of M(  ) distribution near the kinematic limit favors S-wave (CL=0.1%) P-wave:  2 / dof = 71/39 q* 3 roll-off

Possible J PC values (for J ≤ 2) 0 -- exotic violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) (  2 ) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed

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

Could the X(3872) be the  c1 ’ ? Mass is off: theory range 3956  3990 MeV  (  J/  )/  (  J/  ) = 0.14 ± 0.05 is too small –Naïve expectation for  c1 ’ is ~ 40 or higher (  c1 ’   J/  violates isospin) For more details about the results reported here see Belle Note 800 (ver.2 posted today)