S.L.Olsen

1
Non-standard mesons

• S.L.Olsen
• Hawaii

S.L.Olsen Hawaii
Exotic Hadrons WS Nara May 27,2005
2
Representing Belle
Exotic Hadrons WS, Nara May 27, 2005
3
test of QCD running as
4
Probe QCD from other directions

• non-qq or non-qqq hadron spectroscopies
• Pentaquarks
• e.g. an S1 baryon
• Glueballs
• gluon-gluon color singlet states
• Multi-quark mesons
• qq-gluon hybrid mesons

d
u
u
d
s
u
c
u
c
c
c
5
non-standard mesons with hidden charm
u
c
u
c
c
c
(i.e containing c c)

• standard cc mesons are
• best understood theoretically
• narrow non overlapping
• c c systems are commonly produced in B meson
  decays.

c
c
Vcb
b
W-
cosqC
s
CKM favored
6
Thanks to KEKB, Belle has lots of B mesons(gt1M
BB pairs/day)
gt1fb -1/day
Design 10 34
7
Is the X(3872) non-standard?

• B?K pp-J/y

y?pp-J/y
X(3872)?pp-J/y
M(ppJ/y) M(J/y)
8
Its existence is well establishedseen in 4
experiments
PRL 93, 072001
CDF
9.4s
11.6s
X(3872)
PRL 93, 162002
D0
PRD 71, 071103(R)
X(3872)
hep-ex/0406022
9
Is it a cc meson?
Could it be one of these?
3872 MeV
These states are already identified
10
no obvious cc assignment
hc hc cc1 y2 hc2 y3
M too low and G too small
angular distn rules out 1-
3872
G(gJ/y) way too small
G(gcc1) too smallM(pp-) wrong
pp hc should dominate
G( gcc2 DD) too small
SLO hep-ex/0407033
11
go back to square 1

• Determine
• JPC
• quantum numbers
• of the X(3872)
• with minimal assumptions

12
JPC possibilities (for J 2)
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
13
JPC possibilities0-- ruled out JP0,1- 2
unlikely
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
14
Areas of investigation

• Search for radiative decays
• Angular correlations in X?ppJ/y decays
• Fits to the M(pp) distribution
• Search for X(3872)?D0D0p0

15
Search for X(3872)?g J/y
16
Kinematic variables
B?K gJ/y

Ecm/2
e
e-
B? ?B
?(4S)
Ecm/2
DE
CM energy difference
B?K gJ/y
Beam-constrained mass
Mbc
17
Select B?Kg J/y
B?Kcc1 cc1?g J/y
X(3872)?
M(gJ/y)
Mbc
Mbc
13.6 4.4 X(3872)?gJ/y evts (gt4s significance)
Bf(X?gJ/y) Bf(X?ppJ/y)
0.14 0.05
18
Evidence for X(3872)?pp-p0 J/y(reported last
summer hep-ex/0408116)
B-meson yields vs M(pp-p0)
A virtual w(782)?
M(pp-p0) MeV
12.4 4.2 evts
Br(X?3pJ/y) Br(X?2pJ/y)
Large (near max) Isospin violation!!
1.0 0.5
19
C1 is established

• X?g J/y only allowed for C1
• same for X?wJ/y (reported earlier)
• M(pp) for X?pp-J/y looks like a r

CDF
20
JPC possibilities (C-1 ruled out)
0-- exotic Violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
21
Angular Correlations
J/y
Jz0
J0
X3872
J0
K
z
Rosner (PRD 70 094023) Bugg (PRD 71
016006) Suzuki, Pakvasa (PLB 579 67)
pp
22
Use 253 fb-1 ? 275M BB prsexploit the
excellent S/N
X(3872)?pp-J/y
y?pp-J/y
Signal (47 ev)
Sidebands (114/10 11.4 ev)
23
Example 1--
J/y
y
Use B?K y
K
z
y is 1--
dN/dcosq ? sin2qKm
pp
y c2/dof 8.9/9
qKm
K
compute angles in J/y restframe
D.V. Bugg hep-ph/0410168v2
cosqKm
24
cosqKl for X(3872) events
fit with 1--MC bkgd
see 8 evts/bin
c2/dof 45/9
expect 13evts/bin
background scaled from sidebands
X(3872) is not 1-- !
25
0
M ? eJ/y er
In the limit where X(3872), pp, J/y rest frames
coincide dN/dcosqlp ? sin2qlp
qlp
c2/dof 34/9
rule out 0
cosqlp
26
0-
M ? pJ/y (eJ/y x er)
c2/dof18/9
0- sin2q sin2y
q
cosq
c2/dof34/9
y
cosy
safe to rule out 0-
27
1
M ? eX x eJ/y x er
dN/dcosqdcosc ? sin2ql sin2c
c2/dof 11/9
ql
K
cosql
c
c2/dof 5/9
1 looks okay!
cosc
compute angles in X(3872) restframe
28
JPC possibilities (0- 0 ruled out)
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
29
Fits to the M(pp)Distribution
J/y
X?rJ/y has a q(2l1) centrifugal barrier
q
X
q
r
30
M(pp) can distinguish r-J/y S- P-waves
P-wave c2/dof 71/39
S-wave c2/dof 43/39
(CL0.1)
(CL 28)
q roll-off
q3 roll-off
Shape of M(pp) distribution near the kinematic
limit favors S-wave
31
Possible JPC values (J- ruled out)
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
32
X(3872)?D0D0p0?
33
Select B?K D0D0p0 events
D0?D0p0?
M(D0D0p0)
DE
DE
11.33.6 sig.evts (gt5s) Bf(B?KX)Bf(X?DDp)2.20.
70.4x10-4
Preliminary
34
X(3872)?DDp rules out 2

• 1 DD in an S-wave ? q
• 2 DDp in a D-wave ? q5

Strong threshold suppression
35
Eliminate all other factors and the one which
remains must be the truth
Sherlock HolmesThe Sign of Four
36
Possible JPC values (2 ruled out)
0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
1
1
37
can it be a 1 cc state?

• 1 ? cc1
• Mass is 100 MeV off
• cc1 ? r J/y not allowed by isospin.
• Expect
• Bf(cc1?ppJ/y)lt0.1
• BaBar measurement
• Bf(X?ppJ/y)gt4

3872
- G(cc1?gJ/y) / G(cc1?ppJ/y) Expect
40
cc1 component of X(3872) is few

• G(X3872?gJ/y) / G(X3872?ppJ/y)
• Measure 0.14 0.05

38
ee-?BB- K-X0
From BaBar
D()p
fully reconstructed
Jon Coleman Moriond-QCD March 2005
244 fb-1

• Can measure absolute
• B.F.s of B-?K-X0

J/y
Lower limit on BF(X?J/ypp) gt 4.3 _at_ 90 C.L
cc2
cc1
cc0

• Very clear J/y and hc signals
• N J/y258- 42
• N hc 266 -42

• cc2,cc0ltltcc1
• X(3872) production much lower than for other
  Charmonium states
• can set lower limit on B.F.

39
Intriguing fact

• MX3872 3872 0.6 0.5 MeV
• mD0 m D0 3871.2 1.0 MeV

lowest mass charmed meson
lowest mass spin1 charmed meson
X(3872) is very near DD threshold. is it somehow
related to that?
40
D0D0 bound state (deuson)?
Voloshin Okun JETP Lett 23, 333 (1976) Bander
et al PRL 36, 695(1976) DeRujula et al PRL 38,
317 (1977) Manohar Wise, NP B339, 17 (1993)
Tornqvist, Z Phys C61, 525(1994)
Tornqvist hep-ph/0308277
deuteron
deuson
attractive nuclear force
attractive force??
c
c
p
n
D
D
p
p
u
u
2 loosely bound qqq color singlets with Md
mpmn- e
2 loosely bound qq color singlets with M mD
mD - d
41
X(3872) D0D0 bound state?

• JPC 1 is favored
• M mD0 mD0
• Maximal isospin violation is natural ( was
  predicted)
• I1 Iz 0gt 1/?2(DD-gt D0D0gt)
• I0 Iz 0gt 1/?2(DD-gt - D0D0gt)
• ? D0D0gt 1/?2(10gt - 00gt)
• G(X?gJ/y) lt G(X?ppJ/y) was predicted

Tornqvist PLB 590, 209 (2004)
Equal mixture of I1 I 0
Swanson PLB 588, 189 (2004)
Swanson PLB 598, 197 (2004)
42
X(3872) conclusion

• JPC 1
• cc content is small
• matches all(?) expectations for a D0D0 bound
  state

C
C
u
c
u
c
a non-qq meson
43
Are there others?Is the X(3872) a one-of-a-kind
curiousity? or the 1st entry in a new
spectroscopy?

• Look at other B decays ? hadronsJ/y

B?K h J/y
B?K p J/y
B?K w J/y
44
B?K wJ/y in Belle
Y(3940) M3940 11 MeV G 92 24 MeV
Mbc
Mbc
Mbc
Bf(B?KY)Bf(Y?wJ/y)7.11.33.1x10-5
S.K. Choi et al, PRL 94, 182882
45
Y(3940) What is it?
Brambilla et al (QWG) hep-ph/0412158 Eichten,
Lane Quigg PRD 64, 094019 Barnes, Godfrey
Swanson hep-ph/0505002

• Charmonium?
• Conventional wisdom wJ/y should not be a
  discovery mode for a cc state with mass above DD
  DD threshold!
• Some kind of w-J/y threshold interaction?
• the J/y is not surrounded by brown muck can it
  act like an ordinary hadron?

w
J/y
46
Y(3940) What is it (contd)?

• another 4-quark state?
• M 2mDs
• not seen in Y?hJ/y
• (h contains ss)
• width too large??
• no p exchange for DSDS

c
s
s
c
??


PRL 93, 041801
M(h J/y)
47
Y(3940) What is it (contd) ?

• cc-gluon hybrid?
• predicted by QCD,
• decays to DD and DD are suppressed
• (open-charm thresh mD m D 4.3 GeV)
• large hadronJ/y widths are predicted
• masses expected to be 4.3 4.4 GeV (higher than
  what we see)

Horn Mandula PRD 17 898 (1978)
Isgur et al PRL 54, 869 (1995)
Close PLB 342, 369 McNiele et al PRD 65 094505
c
c
48
Summary

• X(3872)
• JPC established as 1
• cc component is small ( few )
• all properties consistent with a D0D0 bound
  state

u
c
a non-standard meson
u
c

• Y(3940)
• No obvious cc assignment
• 4-quark state seems unlikely
• cc-gluon hybrid?

????? needs more study
c
c
49
Mahalo
50
Announcement
51
Back-up slides
52
M(gJ/y) look-back plot
53
Fit cosqlp with 1 MC
c2/dof11.9/9
cosqlp