Transcript Quest in low-energy QCD Are there exotics beyond meson(qq) /baryon (qqq) ? Sakata Model (p, n, L) 6 quark model I II III u c t up Gell-Mann (u,d,s) q q s d down b strange flavor top color （R,G,B） bottom New Hadrons（Exotics） Ordinal Hadrons meson charm q=u, d,

Quest in low-energy QCD
Are there exotics beyond meson(qq) /baryon (qqq) ?
Sakata Model
(p, n, L)
6 quark model
I
II
III
u
c
t
up
Gell-Mann
(u,d,s)
q
q
s
d
down
b
strange
flavor
top
color （R,G,B）
bottom
New Hadrons（Exotics）
Ordinal Hadrons
meson
charm
q=u, d, s, c, b, t
baryon
Tetra-quark
Penta-quark
Molecule
q
q
q
QCD just require hadrons to be colorless, and allow exotics.
Such exotic states exist ?
2
Existence of such exotics have long been discussed
since the birth of the quark model.
Exotic Charmonium-like Spectroscopy
Heavy quarkonium is an ideal tool to study “mesons”.
• Below DD threshold;
– All charmonium states have
been observed.
– Spectra are in good agreement
with naïve quark model
VQCD  
4 S
 kr
3 r
However,
• Above DD threshold;
Observed states DO NOT fit to the
predicted spectrum.
cc
states cannot be

JPC• Charged
Z (4430),
Z  (4050), Z  (4250)
We do not understood yet how hadrons are formed
 from QCD.
4
B Factories
High luminosity e+e- collider and high
performance 4p detectors are essential
for the “bonus” discoveries.
Data taking not only on U(4S) but also
on U(nS) [n=1,2,3,5] and continuum.
• Good acceptance
• Good tracking
• Good Particle ID (e,m,p,K,p)
• Minimum-bias triggers
5
Production of cc in B Factories
B factories can produce charmonium (-like) states in four ways.
6
XYZ at B Factories
State
Mass (MeV)
Width (MeV)
Decay
Production
Ys(2175)
2175±8
58±26
ff0
ISR
X(3872)
3871.84±0.33
<0.95
J/ypp, J/yg
B decay
X(3872)
3872.8 +0.7/-0.6
3.9 +2.8/-1.8
D*0D0, J/yw
B decay
Y(3915)
3915±4
17±10
J/yw
gg
Z(3940)
3929±5
29±10
DD
gg
X(3940)
3942±9
37±17
DD*
Double-charm
Y(3940)
3942±17
87±34
J/yw
B decay
Y(4008)
4008 +82/-49
226 +97/-80
J/ypp
ISR
Z(4051)+
4051 +24/-43
82 +51/-28
pcc1
B decay
X(4160)
4156±29
139 +113/-65
D*D*
Double-charm
Z(4248)+
4248 +185/-45
177 +320/-72
pcc1
B decay
Y(4260)
4264±12
83±22
J/ypp
ISR
X(4350)
4350 +4.7/-5.1
13 +18/-14
J/yf
gg
Y(4350)
4361±13
74±18
y’pp
ISR
Z(4430)+
4433±5
45 +35/-18
y’p
B decay
Y(4660)
4664±12
48±15
y’pp
ISR
Yb(10890)
10889.6±2.3
54.7 +8.9/-7.6
ppΥ(nS)
e+e- annihilation
Zb(10610)
10608.4±2.0
15.6±2.5
(Υ(nS) or hb) p
Υ(5S) /Yb decay
Zb(10650)
10653.2±1.5
14.4±3.2
(Υ(nS) or hb) p
Υ(5S) /Yb decay
Tetraquark
u
c “Di-quark”
c u
D(*)D(*) Molecule
π c
c
u
u
Hybrid
c
c
g
7
Charmonium-like
exotics
8
X (3872)
Discovery by Belle in 2003, followed by D0, CDF, BaBar.
(90%CL)
More recently, also by LHCb, CMS.
9
Properties of X(3872)
• C = +1
X(3872)  J/y g, J/y r seen
Q
• JPC = 1++ or 2-+ Q
Angular distribution
Q
• I=0
No charged partner found so far
 isospin violating decay X(3872)  J/y r (p+p-)
 around D*D MX  M *0  M 0   0.12  0.35 MeV
• Mass just
D
D


MX  MD*  MD    7.74  0.35 MeV
• Possible interpretation
• Conventional cc : cc1(23P1) for 1++, hc2(11D2) for 2-+
• Exotics: 
• D*0 D0 molecule : [cq ][c q]
• Tetra-quark : [cq][c q ]

D*0 D0 molecule
Tetra-quark
10
JPC of X(3872)
CDF(780pb-1) PRL 98, 132002 (2007)
1++
2-+
1-0++
Belle (711fb-1) PRD 84, 052004 (2011)
BaBar (420fb-1) PRD 82, 011101 (2010)
• All JPC values other than 1++ or 2-+ are ruled out with high confidence.
• Need more statistics to distinguish 1++ vs 2-+.
X(3872) in B+ vs B0 decays
PRD 84, 052004 (2011)
DM X  M(X in B  K  X)
Belle (711fb-1)
 M(X in B 0 K 0 X)
 [0.71 0.96  0.19]MeV
B+→K+X(3872)

Prediction by a tetra-quark
model; DM ~ 8 MeV
Maiani et al PRD71, 014028
B0→K0X(3872)
By combining:
M X (3872)
 [3871.85  0.27  0.19]MeV
X (3872)  1.2MeV (90% C.L.)

12
X(3872) at LHC
CMS (40 pb-1,√s = 7 TeV)
R
CMS PAS BPH-10-018
 ( pp  X (3872) K )  Br(X(3872)  J /y p p  )
 ( pp  y (2S) K )  Br(y (2S)  J /y p p  )
 0.087 0.017 0.009
LHCb (34.7 pb-1,√s = 7 TeV)
arXiv: 1112.5310
 ( pp  X(3872) K )
 Br(X(3872) J /y p p  )
 [4.7  1.1  0.7] nb
M X (3872 )  [3871.95  0.48  0.12]MeV
Looking forward to results with >1fb -1 data.
13
Y(4260) / Y(4005)
• BaBar found Y(4260) in ISR e+e- → J/y p+ p- (2005)
• CLEO-c/CLEO III/Belle confirmed, and Belle found also
enhancement near 4005 MeV.
• New BaBar result
Belle (548fb-1)
– Mass/width
M  4244 5  4 MeV
 = 114
+16
-15
 7MeV
PRL99,182004 (2007)
– but, does not confirm Y(4005).

Stay tuned for Belle result
with the full data set.
14
Y(4360) / Y(4660)
• BaBar found Y(4360) in ISR e+e- → y(2S) p+ p- (2005)
• Belle confirmed Y(4360) and found another peak Y(4660)
• New BaBar results confirms Y(4660) [QNP2012/Charm2012]
BaBar 520fb-1, preliminary
Belle 673fb-1
PRL99, 142002 (2007)
(unit: MeV)
M (Y(4360))
 (Y(4360))
M (Y(4660))
 (Y(4660))
Belle (673fb-1)
4361 ± 9 ± 9
74 ± 15 ± 10
4664 ± 11 ± 5
48 ± 15 ± 3
BaBar (520fb-1)
4340 ± 16 ± 9
94 ± 32 ± 13
4669 ± 21 ± 3 104 ± 48 ± 10
15

Z(4430)+, Z (4050)+, Z(4250)+ by Belle
• Belle found Z(4430)+ in BK p+ y’ decays.
– One-dimensional fit on y’p+ distribution after
K*(890) /K*(1430) vetos.
PRD80, 031104(2009)
– Confirmed by analysis with a full Dalitz plot.
15 19
12 13
M  (4443
  (107 86
43
74
56
)MeV/c
2
PRD80, 031104(2009)
)MeV
M2(ψ’π+)
• Belle found also another two states,
Z(4050)+ & Z(4250)+, in BK p+ cc1 decays.
2
M1  (405114 20
41 )MeV/c
M 2  (424844
29
1  (82 21
17
2  (177 54
39
47
22
)MeV
Their minimum quark content
must be exotic:
180
35
316
61
)MeV/c 2
)MeV
cc ud
16
PRD79, 112001(2009)
Z+ (cont’d)
Belle
• BaBar does not confirm Z+’s
– Z(4430)+ search in BKp+y’
– Z(4050)+/Z(4250)+ search in BKp+cc1
– Excess is < 2 w.r.t. Kp reflection.
BaBar
• But, do not rule out Belle’s results.
– UL is statistically compatible with Belle results
Br(B 0 Z K  )  Br(Z  p y ' / cc1)

BaBar U.L.
Belle
Z(4430)+
< 3.1 (95%CL)
Z(4050)+
< 1.8 (90%CL)
4.1 ± 1.0 ± 1.4
3.7
3.0 1.5
0.8 1.6
Z(4250)+
< 4.0 (90%CL)
4.0 2.3
0.9
PRD85, 052003(2012)
19.7
0.5
Note: In the BaBar analyses, Z+ amplitudes are added

Incoherently, therefore, interference
effects are not included.

They are included in the Belle analyses
(see S.Olsen’s summary
talk at CHARM2012, and also backup) .
• Looking forward to the results from LHCb w/ full 2011 data set
!Better statistics than Belle + BaBar ? (ref. A.A.Alves Jr. @ CHARM2012) 17
Bottomonium-like
exotics
18
Nature of (5S)
• Unexpectedly large rate for U(5S)→U(nS)p+p- (n=1,2,3).
(MeV)
PRL100,112001(2008)
PRD82,091106R(2010)
102
• Y(4260) with anomalous
（Y(4260) →J/yp+p-)
line shape
of Yb
(5S)
Exotic Yb just nearby Y(5S) ?
• CLEO observed e+e- → hc p+p- near
Y(4260).
e+e- → hb p+p- near Yb ?
Up+p- peak shifted by 2
w.r.t. U(5S)
19
Search for hb
• Use the missing mass in the reaction;
e+e- → “U(5S)” → X p+p-
2
2
Mmiss
 PU(5S)
 Pp2p 
After background subtraction

hb(2P)
hb(1P)
Mass;
M[hb (1P)]  9898.2
1.1 1.0
1.0 1.2
M[hb (2P)]  10259.8  0.6

MeV/c 2
1.4
1.0
MeV/c 2

P-wave Hyperfine splittings;
DM HF [cbJ (1P)  hb (1P)]  (1.7 1.5) MeV/c 2
2
DM HF [cbJ (2P)  hb (2P)]  (0.51.6
1.2 ) MeV/c
20
Exotic Production Mechanism
Unusually large production rate!
spin-flip
0.07
 [U(5S) hb (nP)p p  ] 0.46  0.080.12 for hb (1P)
 
 
 [U(5S) U(2S)p p ] 0.77  0.080.22
for hb (2P)
0.17
No spin-flip

“(5S)” → (nS)p+p-
“(5S)” → hb(nP)p+p-
Intermediate resonance ?
Charged Bottomonium-like ?
cf) Charm: B → y ‘ pK
B → cc1 pK
Z+(4430)
Z+(4050), Z+(4250)
21
Charged Bottomonium-like Zb+ in (nS)p+
Two peaks at the same positions in the 3 modes.
(1S)
(2S)
(3S)
Two resonances: Zb+(10510), Zb+(10560)
22
hb (1P, 2P) p+ phb(1P) p+
hb(2P) p+
M miss (p ) to look at hb p


Fit with A(Zb1 )  A(Zb 2 )  A(NR)
Two peaks at the positions
same as (nS)pp

23
Zb(10610) & Zb(10650)
M=10608.42.0 MeV
M=10653.21.5 MeV
=15.62.5 MeV
=14.43.2 MeV
24
Nature of Zb+
B*B and B*B* molecule interpretation
Zb+(10510)
[Bondar et al. arXiv:1105.4473]
•
•
•
•
•
•
Masses just above B*B and B*B*
Similar production rate for Zb1 and Zb2
Similar decay width (Zb1)~(Zb2)
+(10560)
Z
b
Why U(5S)→hbp+p- is not suppressed
Relative phase: ~0° for Up and ~180° for hbp
JP=1+ assignment (0± forbidden, 1-, 2± disfavored at ~3)
ū
Bū
B*-
Other interpretation
• Tetra-quark: Karliner-Lipkin (arXiv: 0802.0649),
A. Ali, C. Hambrock, W. Wang (PRD85,
054011(2012))
• Coupled channel resonance: Daniklin et al. (arxiv:1106.1552)
and mode,…
• Cusp: Bugg (arXiv: 1105.5492)
25
Exotics in light flavors ?
• e+e- ISR :
Y(4260)  p+ p- J/y; Y(4360)  p+ p- y’
Y(2175)  p+ p- f (f0 f)
seen by BaBar, Belle, BES III
• gg (two-photon)
X(3915)  w J/y; X(4350)  f J/y
What about wf,ff?
26
gg  VV(wf, ff, ww)
Belle
• 870 fb-1 near U(nS)[n=1,…5]
• 4 charged tracks + p0;
fK+K-, wp+p-p0
• Signals are extracted by fitting
distribution for each M(VV) bin.
hc
cc0 cc2
• Obvious structures in low M(VV)
region.
– JP of the structure is extracted from
angular distributions.
arXiv: 1202.5632, to appear in PRL
27
Summary
• High luminosity e+e- B factories have brought discoveries of
many “exotic” hadrons (unexpected bonus of the B factories).
• Need more statistics to elucidate their properties (spin, parity,
decay modes etc.)
– Super-KEKB/Belle II and INFN
SuperB will improve our
knowledge.
• Possibility to increase c.m.s energy
to cover the bottom flavor region.
– Looking forward to results from
LHC experiments as well.
This is also the area where (super) B factories
and LHC communities can work together !
28
Apology:
Many recent results not covered by this talk
Charmonium(-like)
•
•
•
•
•
•
• Belle: Search for U(2S)ccJ/hc/X/Y + g
• Belle: Search for cbJ  J/yJ/y, J/yy’,
yy
• Belle: Observation of U(1S), U(2S) decay
into light hadrons
• LHCb: Search for X(4140) and X(4274)
Belle: Evidence of 13D2 = y2 in cc1g
Belle: Search for C=-1 state in J/y h
Belle: Search for X(3872) and y2 in cc2g
Belle: Search for ZC+ in BJ/y pK
BaBar: Search for gg  hcp+pBaBar: Confirmation of X(3915) by gg  J/y w
Bottomonium(-like)
•
•
•
•
•
•
•
•
ATLAS/D0: Observation of 33PJ = cb(3P)
Dobbs et al (CLEO data), excess in radiative decay of U(2S)
BaBar: Search for U(3S)  hb p+pApology if I miss any…
Belle: Evidence of 21S0=hb(2S) by hb(2P)hb(2S)g
Apology for missing reference.
Belle: Confirmation of hb(1S) by hb(1P)hb(1S)g
Belle: Confirmation of 13DJ=U(1D)
First meas. of the width
The best precise mass meas.
Belle: Search for U(2S)  hU(1S), U(2S)p0U(1S)
Belle: Search for U(5S)  hU(1S,2S), U(5S)h’U(1S)
29
Backup
30
Search for hb
• Use the missing mass in the reaction;
e+e- → “U(5S)” → X p+p-
2
2
Mmiss
 PU(5S)
 Pp2p 
U(1S)
U(2S) U(3S)
hb(1P) hb(2P)

U(1S)

Accurate background subtraction using high statistics data !
31
(nS)→(nS) pp
M 2 (U(ns) p  )
max
PRL 108, 122001 (2012)
GeV 2 /c 4
(1S)
(2S)
(3S)
M 2 (p p  ) GeV 2 /c 4
• Two horizontal bands in (nS) p

Charged !
• Dalitz plot amplitude analysis;
fitted with

A  A(Zb1
)  A(Zb2 )  A( f 0 (980))  A( f 2 (1275))  A(NR)
32
Search for Charged X
PRD 84, 052004 (2011)
Belle (711fb-1)
B0→K- p+p0 J/y
Br(B KX  )  Br(X   r  J /y )
 4.2  106 for K  K 
 6.1  106 for K  K 0
for 3850 −3890 MeV (90%C.L.)

B+→K0 p+p0 J/y
cf) Br(B  K  X(3872))
Br(X(3872)  p p  J /y )
 [8.63  0.82  0.52]  106
Mbc (GeV)
M (J/y p+ p0) (GeV)

33
Evidence of 13D2 = y2
34
Charged
+
Z
in

p cc1
system?
constr. interf
BaBar (Gradl)
Belle PRD 78, 072004
(2008)