Determination of the JPC of the X(3872)

(Reviews of BN800)

S.L. Olsen & S.K. Choi

Apr 06, 2005 Belle General Meeting

JPC possibilities for J ≤ 2

0 - -

exotic

violates parity

0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S))

1-+

exotic

DD allowed

1++

(c1’)

1+-

(hc’)

2- -

(2)

2- +

(c2)

2++

DD allowed

c2’)

2+-

exotic

DD allowed

P-viol’n & DD-allowed JPCs unlikely(reduce type size of these entries by x1/2)

0 - -

exotic

violates parity

0-+

”)(Not 2 prod)

0++

DD allowed

(c0’)(Not

2prod)

0+-

exotic

DD allowed

1- -

DD allowed

((3S))

Not ee X

1-+

exotic

DD allowed

1++

(c1’)

1+-

(hc’)

2- -

(2)

2- +

(2)

(Not 2 prod)

2++

DD allowed

2’)(Not 2 prod)

2+-

exotic

DD allowed

Use e7 – e37 data(include BKS J/)

Signal(47 ev)Sidebands

(114/10 = 11.4 ev)

Product BF determination

Br(BKX(3872)) x Br(XJ/)

= (1.31±0.24(stat)±0.13(syst))x10-5

Use PDG for ’

Areas of investigation

• Search for radiative decay

• Angular correlations • Fits to the M(pipi) distribution

Search for X(3872) J/

Select BK J/ (include both K± & Ks)

• 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)• R2<0.4; |cosB| < 0.8• |Mbc – 5.28|<0.0055 GeV (2)• |E|<0.034 GeV (2)• E7 E37

BKc1; c1J/

M( J/)

X(3872)?

Use these fits to getmeans & sigmas

for Mbc and EOf X(3872)

|M(J/) – mc1| < 25 MeV (± 2.4)

Mbc & E for 64 MeV-wide M(J/) bins

Nev(X3872) = 13.6±4.4 5.7significance

Background 2.6±0.6Prob : 13.6 <2x10-5

Product BF determination

Br(BKX(3872)) x Br(XJ/)

Nev(XJ/)NBB Br(J/l +l-) (XJ/)

=

= (1.8 ± 0. 6(stat) ± 0.1(syst)) x 10-6

MC:0.19±0.01

Evidence for X(3872) J/( reported last summer hep-ex/0408116

also BN 761)

12.4 ± 4.2 evts

B-meson yields vs M()>755 MeV

C = -1 is ruled outreduce typesize of C=-1 entries

0 - -

exotic

violates parity

0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S))

1-+

exotic

DD allowed

1++

(c1’)

1+-

(hc’)

2- -

(2)2-

+

(c2)

2++

DD allowed

c2’)

2+-

exotic

DD allowed

Angular Correlations

Changes from BAM - Use EvtGen to generate different JPC scenarios. (Thanks to help from Ishikawa-san.) - Use likelihood (<-c2 ) recommended by PDG (& Golob) for low statistics measurements

Strategy: for each JPC, find a distrib 0if we see any events there, we can rule it

out

example1--: sin2K

K

compute angles inJ/ restframe

D.V. Bugg hep-ph/0410168v2

’2/dof = 16.3/9’ is 1--

2/dof = 45.1/9 for X(3872)

events

|cosKl|

signal MC+

background

histogram

backgroundscaled fromsidebands

X(3872) is not 1-- !

Expect 4 binProb : 16 evts ~5x10-5

1+- and 2--

use J/ helicity angle J/

KX

J/

J/

|cosJ/|

For the ’J/,this should be ~flat

1+-: sin2J/

2--: sin2J/ cos2J/

|cosJ/|

2/dof =31.6 /9

2/dof =19.5 /9

rule out 1+-

2-- unlikely

0-+

Rosner (PRD 70 094023)

0-+ : sin2 sin2

safe to rule out 0-+

2/dof=17.7/9

|cos|

|cos|

2/dof=34.2/9

0 ++

Rosner (PRD 70 094023) again

l

In the limit whereX(3872), , & J/rest frames coincide:d/dcosl sin2l

|cosl|rule out 0++

2/dof = 41.0/9

2/dof = 30.1/9

1++

l

1++: sin2l sin2

K

Rosner (PRD 70 094023)

2/dof = 5.0/9

2/dof = 13.5/9

2/dof = 11.4/9

2/dof = 10.0/9

compute in X and J rest frame

compute in X and rest frame

|cos||cosl| 1++ looks okay!

Reduce type size for JPC values that fail angle tests

0 - -

exotic

violates parity

0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S))

1-+

exotic

DD allowed

1++

(c1’)

1+-

(hc’)

2- -

(2)

2- +

(c2)

2++

DD allowed

c2’)

2+-

exotic

DD allowed

Remaining states

•1++ & J/ in an S-wave •2-+ “ “ a P-wave

Fits to the M()

DistributionXJ/ in P-wave has aq*3 centrifugal barrierX

J/

q*

q*

M()- dependence of the detection efficiency

M() can distinguish -J/ S- & P-waves

S-wave: 2/dof = 43.1/39 P-wave: 2/dof = 71.0/39

q*roll-off

q*3

roll-off

(CL=0.1%)(CL= 28%)

Shape of M() distribution nearthe kinematic limit favors S-wave

-J/ in a P-wave is unlikelyreduce type-size of all J-+ entries

0 - -

exotic

violates parity

0-+

(c”)

0++

DD allowed

(c0’)

0+-

exotic

DD allowed

1- -

DD allowed

((3S))

1-+

exotic

DD allowed1++

(c1’)

1+-

(hc’)

2- -

(2)

2- +

(c2)

2++

DD allowed

c2’)

2+-

exotic

DD allowed

• Mass is way off: 3872 vs 3929 3990 MeV

• we measure

• Rough Expectation for pure charmonium

Could the X(3872) be the c1’ ?

(23P1 J/) ~ 11 keV

(23P1 J/) ~ (’ J/) ~ 0 (0.3 keV)~ 30

isospin violating

Barnes, Godfrey hep-ph/0311162

0.14+-0.05 is too small compare to 30

c1’ component of the X(3872) must be small

theory range

Summary

• 1++ passes all the tests • consistent with observations of:

X J/& X”” J/• angular distributions & M() fitted well

• c1’ assignment unlikely (Br(J/) is too small)

– DD* molecule models favor 1++ » Tornqvist hep-ph/0308277» Swanson PLB588, 189(2004)

• 2++ : this is ruled out by Garima et al & Jolanta et al by observation of X DD* ( but not by this analysis)