Searching for new forms of hadronic matter

1
Searching for new forms of hadronic matter
Wuhan ?? 10/15/07
Stephen L. Olsen University of Hawaii ?????
??
2
History(sub-atomic particles)

• 1932 proton neutron
• ..all we need???
• 1937 muon
• Who ordered that?
• 1947 pion
• predicted in 1935
• 1950s ?,?,?,?,?,
• Had I foreseen that, I would have
• gone into botany Fermi

Joliet-Curie
chadwick
Rabi
Yukawa
Fermi
Ting
Peters
Jones
3
Hadron zoo
mesons
baryons
No economy
4
Constituent Quark Model 1964
3 quarks
( 3 antiquarks)
Gell-Mann
u2/3
u-2/3
d-1/3
s-1/3
d1/3
s1/3
Zweig
Baryons qqq
Mesons q
q
u2/3
u2/3
p
u2/3
p
d-1/3
d1//3
u-2/3
u-2/3
u-2/3
p
p-
d1/3
d-1/3
5
Constituent Quark Model 2007
6 quarks
( 6 antiquarks)
c-2/3
t-2/3
u-2/3
c2/3
t2/3
u2/3
b1/3
s1/3
b-1/3
d1/3
d-1/3
s-1/3
Baryons qqq
Mesons q
q
c2/3
s1/3
Wc
u2/3
B
s-1/3
b1//3
C-2/3
u-2/3
S1/3
Wc
B-
s1/3
b-1/3
6
Fabulously successful at bringing order to the
hadron zoo
q
q
mesons
q
baryons
q
q
economyis recovered
7
Fabulously successful, but

• Why are isolated quarks are not seen?
• why only qqq and qq combinations?
• What about spin-statistics?

8
W-
s-1/3
s-1/3
s-1/3
three s-quarks in the same quantum state
??
9
The charge for the strong forceis a 3-dim
spinor
Each quark can have 3 different color charges
W-
Y. Nambu
O. Greenberg
s-1/3
s-1/3
s-1/3
the 3 s-1/3 quarks in the W- have different
color charges evade Pauli
10
QCD Gauge theory for color charges
Yang Mills
Nambu Fritzsch GellMann
generalization of QED
QED
er eb eg
QCD
scalar charge e
triplet charge
QED gauge Xform
QCD gauge Xform
? ? ? i e A
? ? ? i a li Gi
8 vector fields (gluons)
1 vector field (photon)
eight 3x3 SU(3) matrices
11
Attractive configurations
eijk eiejek i ? j ? k
dij ei
ej
same as the rules for combining colors to get
white add 3 primary colors or add
colorcomplementary color
quarks eiejek ? color charges
antiquarks ? anticolor charges
ej
ei
ek
Hence the name Quantum Chromodynamics
12
Difference between QED QCD

• QED photons have no charge
• QCD gluons carry color charges
• gluons interact with each other

a
Coupling strengths
distance
13
Test QCD with 3-jet events( deep inelastic
scattering)
as
gluon

as
rate for 3-jet events should decrease with Ecm
dist
?Energy
14
running as
Winners of the 2004 Nobel Prize
15
Running as tests QCD at short distances only
The long-distance regime, where the matter we are
made of exists, remains untested.
a
distance
16
Are there other color-singlet arrangements?
Non-quark model states expected in QCD

• Pentaquarks
• e.g. an S1 baryon
• (only anti-s quark has S1)
• Glueballs
• gluon-gluon color singlet states
• Multi-quark mesons
• qq-gluon hybrid mesons

d
u
u
d
s
u
c
u
c
c
c
17
Spring8 electron Ring in Japan
18
A pentaquark?
g n ? K- K n
Q(1530)?
S1 baryon impossible with only qqq
d-1/3
u2/3
u2/3
d-1/3
s1//3
M(Kn)
T.Nakano et al (LEPS) PRL 91 012002 (2003) ? 742
citations!!
19
Experimental situation is messy(some
contradictory experiments)
CLAS (2005)
SAPHIR (2004)
4.8?
Counts/4 MeV
Same reaction
M(nK)(GeV)
20
Some groups contradict themselves
gd?pK-Kn
CLAS-D (2005)
CLAS-D (2003)
5.2?
???
21
Pentaquark Scoreboard
Positive signals
Negative results
Also Belle Compass L3
CLAS
Yes 17
No 18
22
Status in 2006

• The conclusion that pentaquarks in general, and
  the Q in particular, do not exist, appears
  compelling.
• -

George Trilling LBL
23
This is a risky business
You never know if nature is smiling at you
or something else
24
Another approach look for non-qq mesons
4 ( 6) quark states
d
u
u
c
u
d
u
u
c
u
hybrid qq-gluon states
theory mc2gt4.2 GeV
c
c
25
The Beijing Electron Positron Collider (BEPC)
???????
e
e-
26
Beijing Spectrometer (BES)
27
ee- annihilation cross section
BES Energy Range


ss
cc
bb
q
q
Ecm(GeV)
28
J/y ? g pp
g

c2/3
C-2//3
p
d
u
u
u
d
u
p
29
J/y ? g pp
What is this???
BESII
This is the hc?pp the J/ys well known S0 partner
M(pp) GeV
J.Z. Bai et al. (BESII) PRL 91 022001 (2003)
30
Fit the M(pp) distribution
Best fit to this peak is a resonance with peak
mass below the pp mass threshold

• M1830.6 6.7 MeV/c2
• lt 153 MeV/c2 (90 CL)
• matches to no known state.

31
A pp bound state (baryonium)?
There is lots lots of literature about this
possibility
deuteron
baryonium
attractive nuclear force
attractive force?
p
n
p
p
loosely bound 3-q 3-q color singlets with Md
2mp- e
loosely bound 3-q 3-q color singlets with Mb
2mp-d ?
32
An old idea
33
Fermi Yang in 1949 (7 years before p
discovery) If NN potential is attractive,
they could bind to form p-like states.
34
Expectation for pp bound state meson
below-threshold p and p annihilate to mesons
Above threshold X?pp 100
I0, JPC0- init. state pp ? pp-h is common
mp mp
Ding Yan Phys.Rev.C72015208,2005.
35
BES looked at J/y ? g pp-h
mpmp
BESII
These values match those for the pp peak (as
predicted by DingYan)
M1833 MeV G ? 70MeV
M(pp-h)
M. Ablikim et al. (BESII) PRL 95, 262001 (2005)
36
X(1835) a6-quark meson?
u
d
3 quarks
u
u
u
3 antiquarks
d

• Need to confirm JPC of the pp-h peak is 0-
• Need to find it in other common 0- pp
  annihilation channels

job for BESIII
37
Move over to Japan
Tsukuba Mountain
KEKB Collider

KEK laboratory
38

39
International Collaboration Belle
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ee- annihilation cross section
KEK B-factory


ss
cc
bb
q
q
Ecm(GeV)
41
B meson decays
C2/3
Charmonium
b-1/3
C-2/3
W-
u-2/3
S-1/3
K-
u-2/3
42
Primer on Charmonium
43
Charmonium
mesons formed from c- and c-quarks
r
c
c
c-quarks are heavy mc 1.5 GeV ? 2mp
velocities small v/c1/4 non-relativistic QM
applies
44
QM of cc mesons
c
c
r
What is V(r) ??
derive from QCD
quantum chromodynamics
45
Cornell potential
c
c
r
slope1GeV/fm
0.1 fm
confining large distance component
V(r)
1/r coulombic short distance component
G.S.Bali hep-ph/0010032
2 parameters slope intercept
46
Charmonium spectrum
y
y
All of these states are well established
hc
hc
cc0,1,2
J/y
hc
47
Study B?K-pp-J/y
p
look here
J/y
C2/3
p-
b-1/3
C-2/3
W-
u-2/3
S-1/3
u-2/3
K-
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The X(3872)

• B?K pp-J/y

y?pp-J/y
X(3872)?pp-J/y
M(ppJ/y) M(J/y)
S.K. Choi et al PRL 91, 262001
49
Its existence is well establishedseen in 4
experiments
CDF
9.4s
11.6s
X(3872)
D0
X(3872)
hep-ex/0406022
50
Is it a cc meson?
Could it be one of these?
3872 MeV
These states are already identified
51

• The JPC quantum numbers
• of the X(3872) are 1
• From studying different decay processes
• angular correlations among decay products

52
can it be the 1 cc state?
1?cc1 (the only charmonium possibility)
23P1 cc state
M3872 MeV is low,
3872
X?pp- J/y decay is a forbidden decay
g
pp-
(Isospin violating)
Allowed E1 transition
53
Intriguing fact

• MX3872 3871.2 0.5 MeV
• mD0 m D0 3871.6 0.4 MeV

lowest mass charmed meson
lowest mass spin1 charmed meson
Deuson? deuteron-like DD bound state?
2 loosely bound qq color singlets with M mD
mD - d
c
c
D
D
p
u
u
Tornqvist PLB 590, 209 (2004) Braaten et al, PRL
93, 162001
one p exchange attractive for 1
54
Another old ideaDeRujula, Georgi,Glashow, PRL
38, 317 (1977)
X(3872)??
55
X(3872) summary

• Existence well established
• JPC 1
• Br(X?pp- J/y) too high for charmonium
• Mass too low for hybrid

Four years after discovery, theorists are still
puzzling over what it may be
56
Next, California
Stanford Linear Accelerator Ctr
BaBar Detector
57
Radiative return
B-factory energies

g

ss
cc
bb
35 GeV
10.58 GeV
Ecm(GeV)
58
Y(4260)
10.58 GeV
M4259 ? 8 MeV G 88 ? 23 MeV
4.26 GeV
not seen in s(ee-?hadrons) at Ecm 4.26 GeV
Y(4260)
BES
s(ee-?hadrons)
J/? sideband
B. Aubert et al. (BaBar) PRL 95 142001 (2005)
J.Z. Bai et al. (BESII) PRL 88 101802
Well above DD DD threshold but wide found in
a suppressed mode??
59
a 1-- cc slot for the Y(4260)?
X.H. Mo et al, hep-ex/0603024
4260

4260
no cc slot for it!
J.Z. Bai et al. (BESII) PRL 88 101802
60
Theorists favorite interpretation
hybrid qq-gluon states
c
c
just about the right mass for theory
61
A pp-y peak at 4325MeV
D2D
298 fb-1 (BaBar) hep-ex/0610057
ee-?gISR pp- y
D1D
Nevt 68 (lt5.7 GeV/c2)

Nbkg 3.1 ?1.0
M4324 ? 24 MeV G 172 ? 33 MeV
Not Compatible with the Y(4260)
?2-prob lt 5.7 GeV/c2
Y(4260) 6.5 ?10-3
?(4415) 1.2 ?10-13
Y(4320) 29
BaBar PRL 98 252001 (2007)
S.W.Ye QWG-2006 June 2006
62
New results on the pp-y peak from Belle

It is really two peaks!
(both relatively narrow)

(neither one consistent with 4260)
M4361 ? 9 9 MeV G 74 ? 15 10 MeV




4260
M4664 ? 11 5 MeV G 48 ? 15 3 MeV
X.L. Wang et al (Belle) arXiv0707.3699
548 fb-1
63
Need 2 more 1-- cc slots for Y(4630) Y(4660)
X.H. Mo et al, hep-ex/0603024
4660
4260
4360

4260
Excited hybrid states?
c
c
64
Latest News
electrically charged!!
65
M(py) from B?K p y
M 4433 4 1 MeV Gtot 45 17 30 MeV
Nsig 124 31evts
-13
-11
6.5 ?
M(py) GeV
K. Abe et al (Belle) arXiv0708.1790
66
Cant be a cc meson or a hybrid
4660

4360
4260
No charged cc hybrid states gluons have zero
charge
C2/3
C-2/3
67
Summary
Mesons with no qq assignment
X(1835)
Y(4260)



BESII
X(3872)?pp-J/y
M(ppJ/y)
M(pp) GeV
M(ppJ/y) M(J/y)
Z(4430)
Y(4360)
Y(3940)
Y(4660)
M(wJ/y) MeV
M(py) GeV
548 fb-1
68
Concluding remarks

• A number of mysterious mesons that dont fit
  into the simple quark model picture have been
  found
• If they are related to each other, these
  particles cant be the hybrid states predicted by
  QCD
• Are these curiosities, each with its own story?
• or are they 1st signs of a spectroscopy of
  new forms of hadronic matter?
• Hopefully, time, more experimentation, will
  tell

69
??
70
Thank you
71
Back-up slides
72
Conclusion

• either
• The constituent quark model for mesons needs
  major revision
• or
• There is a new, non-qq, hadron spectroscopy,
  maybe more than one.

73
Difference between QED QCD

• QED photons have no charge
• QCD gluons carry color charges
• gluons interact with each other

74
Vacuum polarization QED vs QCD
2nf
11CA
in QCD CA3, this dominates
75
The LEPS observation of Q(1530)
Q(1530)
K
K-
n
g n ? K- Q ?K- K n
n
M(K n)
d-1/3
u2/3
g
g n ? K- K n
u2/3
d-1/3
s1//3
S1
Physical Review Letters, 91, 012002 (2003)
76
Charmonium state?
No place for it!
No sign of it s(ee-?hadrons) at Ecm 4.26 GeV
4260
BES
s(ee-?hadrons)
J.Z. Bai et al. (BESII) PRL 88 101802
77
Actual fit
fitted peak location
J/y?gpp in the BES expt
M1830.6 6.7 MeV/c2 G lt 153 MeV/c2 (90 CL)

c2/dof56/56
0
0.1
0.2
0.3
78
A pp bound state (baryonium)?
There is lots lots of literature about this
possibility
These are very famous papers
deuteron
baryonium
attractive nuclear force
attractive force?
!!!

• E. Fermi, C.N. Yang, Phys. Rev. 76, 1739 (1949)
• Y.Nambu, G. Jona-Lasinio Phys Rev 122, 345 (1961)
  
• I.S. Shapiro, Phys. Rept. 35, 129 (1978)
• C.B. Dover, M. Goldhaber, PRD 15, 1997 (1977)
• Datta, P.J. ODonnell, PLB 567, 273 (2003)
• M.L. Yan et al., hep-ph/0405087
• B. Loiseau et al., hep-ph/0411218

p
n
p
p
loosely bound 3-q 3-q color singlets with Md
2mp- e
loosely bound 3-q 3-q color singlets with Mb
2mp-d ?
79
The X(3872)
Study pp-J/y produced in B?K pp- J/y decays
????
80
hadronic moleculesa new spectroscopy?
may be more particles to find
81
summary

• X(1835)
• Existence well established
• JPC 0-
• Br(X?pp) too high for qq meson
• X?pp-h is expected for sub-thresh pp state

82
0 0-
er?eJ/y
k?(erxeJ/y)
Ruled out by Belle
qlp
y
c2/dof34/9
c2/dof 34/9
cosq
cosqlp
cosy
rule out 0 0 -
83
C1 is established
M(pp) looks like a r
X(3872)?gJ/y seen in
CDF
PRL 96 102002
Belle
hep-ex/0505037
Belle

X(3872)?wJ/y seen
Belle
84
Angular analysis from CDF
1 or 2-
CDF Collab. PRL 98, 132002 (2007)
85
Use Angular Correlations to determine J P
r?pp-
Jz0
J0
X3872
J0
K
z
Rosner (PRD 70 094023) Bugg (PRD 71
016006) Suzuki, Pakvasa (PLB 579 67)
J/y?mm- (ee-)
86
Possible JPC values
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
87
X(3872) D0D0 bound state?

• JPC 1 is favored
• M mD0 mD0
• Large isospin violation is natural ( was
  predicted)
• ? D0D0gt 1/?2(10gt - 00gt)
• G(X?gJ/y) lt G(X?ppJ/y) was predicted
• G(X?D0D0p0) too large?
• Bf(B0?K0X3872)/Bf(B?KX3872) too large?

Tornqvist PLB 590, 209 (2004)
Equal mixture of I1 I 0
Swanson PLB 588, 189 (2004)
Swanson PLB 598, 197 (2004)
Braaten Kusunoki PR D71, 074005 predict
lt0.08 BaBar measurement (hep-ex/0507090) 0.5
? 0.3
88
Y(3940) in B?K wJ/y
Belle PRL94, 182002 (2005)
M3940 11 MeV G 92 24 MeV
M2(wJ/y) GeV2
M2(Kw) GeV2
M(wJ/y) MeV
89
If not charmonium, what?
c
c
hybrid cc-gluon state?
But why does it decay to pp- J/y, and not to D
and D mesons?
90
Y(4260) summary

• Existence well established
• JPC 1--
• G(X?pp- J/y) too high for charmonium
• Br(X?D()D()) too low for hybrid

Another mystery!!
91
J/y ? g pp
g

c2/3
p
C-2//3
u2/3
u2/3
d-1/3
p
u-2/3
u-2/3
d1/3