1. Introduction and Status of QCD Exotics
K. Peters
GSI Darmstadt/JWGU Frankfurt
Hadron Physics at COSY 2005
Bad Honnef, July 25-29

2. Status of Spin-Exotics Status of Glueball-Search Future Experiments
Overview
K. Peters - Status of QCD Exotics
Introduction
Status of Spin-Exotics
Status of Glueball-Search
Future Experiments
Not covered
Pentaquarks
Baryonium
Charmonium-Spectrum

3. What are EXOTIC hadrons ?
K. Peters - Status of QCD Exotics
Unconventional hadrons
Depends on what is the convention
Convention
Matter is build out of quarks
proton consists of 3 quarks
pion consists of a quark and an antiquark
Unconventional
Hadronic matter is not made entirely out of quarks
Quark configurations different from baryons and mesons
But not forbidden !

4. Classification (Close & Lipkin)
K. Peters - Status of QCD Exotics
Exotics of the first kind
External quantum numbers unambiguously incompatible with assignment to baryons or mesons
B=1 – baryon-like
Q>2, Q<-1, S<-3, S>0, I>3/2, ....
B=0 – meson-like
|Q|>1, I>1, |S|>2, |C|>2, |S-C|>1, .... 1

5. Classification (Close & Lipkin)
K. Peters - Status of QCD Exotics
Exotics of the second kind
Combination of quantum numbers not allowed for leading Fock-term
Only possible for B=0
JPC = 0--, 0+-,1-+, 2+-, ...
cannot be formed by any unexcited qq-System 2

6. Classification (Close & Lipkin)
K. Peters - Status of QCD Exotics
Exotics of the third kind – Crypto-Exotics
Internal exotic structure
like gluonic excitations
like N-quarks
but no model free signature
approach:
overpopulation of hadron multiplets
unexpected masses and decay properties
a well understood conventional meson picture is mandatory 3

7. Meson Spectrum after the LEAR Era
K. Peters - Status of QCD Exotics
The LEAR Era with
the experiments
@ CERN
Asterix/Obelix
Crystal Barrel
Jetset/PS185
WA102/Gams
@ BNL
E818/E852
@ FNAL
E760/E835
@Serpukhov
VES/Gams
produced impressive results with high statistics and high resolution

8. SPIN-PARITY EXOTICS (2nd Kind) Search for Hybrids
K. Peters - Status of QCD Exotics
SPIN-PARITY EXOTICS
(2nd Kind)
Search for Hybrids

9. Intermediate State Mixing
K. Peters - Status of QCD Exotics
Many states may contribute to a final state
not only ones with well defined
(already measured) properties
not only expected ones
Many mixing parameters are poorly known
K-phases
SU(3) phases
In addition
also D/S mixing (b1,a1 decays)

10. S-Wave+Gluon (qq)8g with ()8=coloured 1S0 ­¯ 3S1 ­­
Simplest Hybrids
K. Peters - Status of QCD Exotics
S-Wave+Gluon (qq)8g with ()8=coloured
1S0 ­¯ 3S1 ­­
combined with a 1+ or 1- gluon
Gluon
1– (TM)
1+(TE)
1S0, 0–+
1++
1––
3S1, 1––
0+-
0–+
1+-
1–+
2+-
2–+
Meson – Hybrid Mixing q
g MIX
g FSI

11. Fluxtube Predictions (u,d)g (n,s)g ccg
K. Peters - Status of QCD Exotics
N. Isgur, R. Kokoski und J. Paton, Phys. Rev. Lett. 54 (1985) 869 and refs therein
F.E. Close und P. R. Page, Nucl. Phys. B443 (1995) 233
(u,d)g
(n,s)g
ccg

12. recent new determination of exotic 1-+ hybrid meson
Light-quark hybrids
K. Peters - Status of QCD Exotics
recent new determination of exotic 1-+ hybrid meson
improved staggered fermions (lighter quark masses)
quenched and unquenched, Wilson gluon action
a ~ 0.09 fm
lightest mass still above experiment
(around strange quark mass)
quenched continuum limit
MILC, hep-lat/

13. Rediscovery of the p1(1400) pd  π-π0η p @ Rest in liq.D2
K. Peters - Status of QCD Exotics
pd  π-π0η Rest in liq.D2
πp  π-η p (and π0η n)

14. Proof of evidence for exotic wave - CB
K. Peters - Status of QCD Exotics

15. Controversary in E852 FSI Description in ηπ-
K. Peters - Status of QCD Exotics
FSI Description in ηπ-
Szczepaniak, et al., PRL 91, (2003)

16. Controversary in E852, cont‘d
K. Peters - Status of QCD Exotics
in E852 in ηπ0
the amplitudes are different for different regions
BW solution fails

17. 1400 MeV/c2 region well established
π1(1400) Summary
K. Peters - Status of QCD Exotics
1400 MeV/c2 region well established
phase motion against a2(1320) in π-p
interference with ρ(770) in rest
signal in πη is at b1π and f1π threshold
influences results
line shapes and pole positions affected
exotic wave is evident
it might span over a wide range
is it a Hybrid? probably not – decuplet state?

18. E852 ρπ
K. Peters - Status of QCD Exotics
π-p  π-ρ0p  π-π-π+p
shows a clear resonance in the 1-+ wave around
1600 MeV/c2

19. VES η‘π resonant structure η and η‘ are coupled via SU(3) Verification
K. Peters - Status of QCD Exotics
resonant structure
in η‘π at 1600 MeV/c2
in ηπ at 1400 MeV/c2
η and η‘ are coupled via SU(3)
any interpretation of the π1 resonances have to explain the difference
Verification
of πη(') results
in ρπ channel
ρ(16xx) observed
by two independent
experiments in ρπ and η‘π
E852

20. E852 f1π and b1π blue one 1-+ pole black two poles c2=70.6/47=1.5 E852
K. Peters - Status of QCD Exotics
E852
E852
E852
blue one 1-+ pole
black two poles
c2=70.6/47=1.5

21. E852 more b1π first observation of a non 1-+ exotic
K. Peters - Status of QCD Exotics
first observation of a non 1-+ exotic
h2(1950) with JPC=2+-
M=1954±8
Γ=138±3
another h2 may be at M=2300

22. Spin-exotic Summary K. Peters - Status of QCD Exotics
thanks to G. Adams, RPI

23. P P S S Charmed Hybrids LQCD:
K. Peters - Status of QCD Exotics
LQCD:
gluonic excitations of the quark-antiquark-potential may lead to bound states
S-potential
for one-gluon exchange
P-potential
from excited gluon flux
mHcc ~ GeV/c2
Light charmed hybrids could be narrow if open charm decays are inaccessible or suppressed
V(R)/GeV P P
Hcc 4
J/ψ χc ψ‘ S S DD
3.5 3
R/r0 1 2
important <r2> and rBreakup

24. K. Peters - Status of QCD Exotics
GLUEBALLS
(usually 3rd Kind)

25. SU(N) Glueballs on the Lattice
K. Peters - Status of QCD Exotics
recent study of 0++,2++, 0++* glueballs in SU(N), N=2,3,4,5
masses depend linearly on N
large N limits differ little from N=3
Lucini, Teper, JHEP 06, 050 (2001).
Morningstar und Peardon, PRD60 (1999)
Morningstar und Peardon, PRD56 (1997) 4043

26. f0(1500) – Crystal Barrel @ LEAR
K. Peters - Status of QCD Exotics
f0(1500) – Crystal Barrel LEAR:
Das f0(1500) wurde in vielen Zerfallskanälen gefunden:
(Bilder von pipi, etaeta, etaeta‘, 4pi und KSKS.)
Das Zerfallsmuster und die sehr geringe Breite deuten auf eine exotische Natur hin.
Insbesondere sind f0(1370) und f0(1500) nicht kompatibel als isoskalares Paar der skalaren Mesonen.
(Kleine Tabelle hierzu.)
In allen anderen Nonetts lassen sich alle Zerfälle mit SU(3) gut beschreiben.
[Verweis auf Folie SU(3).]
f0(1500) is very narrow (~100 MeV/c2)
and decays dominantly to (2n)π

27. fj(1710) in radiative J/y decays
K. Peters - Status of QCD Exotics
Mark III and DM2
found a scalar resonance @ 1700 MeV/c2
in KK in radiative decays of the J/y
It took more than a decade to establish the scalar nature of this object
MarkIII
DM2

28. SOZI - DOZI - Analysis f0(1500) in 4π and fj(1710) in KK
K. Peters - Status of QCD Exotics
f0(1500) in 4π and
fj(1710) in KK
“DOZI”-enhanced
both should contain remarkable gg content

29. Central Production CERN-experiments: WA76, WA91, WA102
K. Peters - Status of QCD Exotics
CERN-experiments: WA76, WA91, WA102
Important results in the
scalar (ππ,KK,KsKs,4p)
tensor (ππ,KK,KsKs,4p)
pseudoscalar (KKπ,ππη)
sectors
But:
s ~ 1/M2
no charm-sector
partial wave (moment)-analysis complicated
little фф,ωω statistics
Future:
Compass, much higher statistics

30. Meson Glueball Mixing Physical Masses f0(1370),f0(1500),f0(1710)
K. Peters - Status of QCD Exotics
Physical Masses
f0(1370),f0(1500),f0(1710)
Bare Masses:
m1,m2,mG
(G) (S) (N)
f0(1370) -0.69  0.07
f0(1500) -0.65 0.04 –0.700.07
f0(1710) 0.39  0.02
octet
piece
m1=137720 m2=167410 mG=144324
Lattice of about 1600

31. K-Matrix approach M= 280 – 1900 MeV
Anisovich & Sarantsev
K. Peters - Status of QCD Exotics
Anisovich and Sarantsev, hep-ph/
K-Matrix approach M= 280 – 1900 MeV
Uses data from
GAMS at small and large nucleon momentum
E852
CERN-Munich scattering
Crystal Barrel
For the channels ππ, ηη, ηη‘, KK, ππππ
No f0(600) = σ
Found f0(980), f0(1300), f0(1500),
f0(1750) and f0( )

32. DS+  π+π-π+ (+c.c) E791 848 E. D DS BaBar 2903 E.
K. Peters - Status of QCD Exotics
E791
848 E.
E.M. Aitala et al., PRL 765 (2001) D DS
BaBar
2903 E.
PRELIMINARY
B. Lewandowski, Proc. Meson 2002
PHD Th. Deppermann, Bochum 2003
non-unitary approach needs interference of 4 resonances for the strange peak  K-Matrix approach resolves it

33. D+  π+π-π+ (+c.c) non-unitary approach yields 50% σ
K. Peters - Status of QCD Exotics
non-unitary approach yields 50% σ
 K-Matrix approach removes any σ contribution
E791
E.M. Aitala et al., PRD 770 (2002)
1172 E.

34. Problems in Analysis and Interpretation
K. Peters - Status of QCD Exotics
I=0,p
KK* or c.c. _ p+ W c s _
direct
FSI
many processes, therefore no trivial production amplitude
coupled channels contain very many production amplitudes
complicated interferences
in K0SK0S contr.
from K0K0 and K0K0 W c s _
DCS no
only K0K0*+c.c. W c s _
ColorS
FSI
direct W c s _
FSI
direct

35. most interpretations assume
The scalar particles
K. Peters - Status of QCD Exotics
most interpretations assume
the doubtless K0*(1430) from LASS to be the I=1/2-state
and that the a0(1400) is the I=1-state
two classes of arrangements
a0(980) & f0(975) are isospin-partner
a0(980) & f0(975) are completely independent
a reasonable model must be able to handle the mixing of isoscalars
as well as t- and u-channel exchange

36. Scalar Summary Puzzle still unsolved ....
K. Peters - Status of QCD Exotics
Puzzle still unsolved ....

37. 2 GeV Tensors Sorted by measured final state Structure unclear
K. Peters - Status of QCD Exotics
Sorted by measured
final state
Structure unclear

38. f2(1920)
K. Peters - Status of QCD Exotics

39. f2(2200) Broad resonance at 2.2 GeV/c2
K. Peters - Status of QCD Exotics
Broad resonance
at 2.2 GeV/c2

40. Many Spin-Parity Exotics
SUMMARY and OUTLOOK I
K. Peters - Status of QCD Exotics
Hybrids
Many Spin-Parity Exotics
π1(1400) ***
π1(1600) ****
π1(2000) **
h2(1950) *
h2(2300) (*)
Future investigations
GlueX for the light quark sector
Panda for the onia and heavy light sector

41. Too many scalars with an unclear nature
SUMMARY and OUTLOOK II
K. Peters - Status of QCD Exotics
Glueballs
Too many scalars with an unclear nature
experimental situation fairly good, saturated
D(s)-decays can not help solving this issue
Many unconfirmed tensors
important field for the future to settle the spectrum
BESIII and Panda are well suited

42. K. Peters - Status of QCD Exotics
FUTURE EXPERIMENTS

43. Implications for exotic meson searches
K. Peters - Status of QCD Exotics
Possible narrow QCD exotic (M=1.6 GeV) (E852 π-p  π+π-π-p)
pion
Szczepaniak & Swat (01)
photon
π-p  X0n
γp  X+n
exotic/non-exotic ~ 0.1
exotic/non-exotic ~ 1

44. Hall D @ JLab and the 12 GeV Upgrade
K. Peters - Status of QCD Exotics
Upgrade magnets and power supplies
CHL-2
Construction start ?
Physics ?+4

45. The GSI Future Facility
K. Peters - Status of QCD Exotics
Panda
Existing GSI Facilities

46. Accessible Charmed Hadrons at PANDA @ GSI
K. Peters - Status of QCD Exotics 2 4 6 8 12 15 10
p Momentum [GeV/c]
Mass [GeV/c2]
Two body
thresholds
Molecules
Gluonic
Excitations
qq Mesons 1 3 5
Hybrids
Hybrids+Recoil
Glueball
Glueball+Recoil ΛΛ ΣΣ ΞΞ
ΛcΛc
ΣcΣc
ΞcΞc
ΩcΩc ΩΩ DD
DsDs
qqqq
ccqq
nng,ssg
ccg
ggg,gg
light qq
π,ρ,ω,f2,K,K* cc
J/ψ, ηc, χcJ
ggg
exotic
charmonium
conventional
charmonium
Other exotics with identical decay channels ® same region

47. BES III @ BEPC2 BEPC2 will operate as τcf and synchrotron light source
K. Peters - Status of QCD Exotics
BEPC2 will operate as τcf and synchrotron light source
Start of operation 2007

48. BES III Physics Performance Example
K. Peters - Status of QCD Exotics
J/ψ  ρ0ηπ0
Well identified
ρ(1390)
ρ(2300)
via partial wave
analysis