Introduction and Status of QCD Exotics K. Peters GSI Darmstadt/JWGU Frankfurt Hadron Physics at COSY...
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Transcript of Introduction and Status of QCD Exotics K. Peters GSI Darmstadt/JWGU Frankfurt Hadron Physics at COSY...
Introduction and Status of QCD Exotics
K. PetersGSI Darmstadt/JWGU Frankfurt
Hadron Physics at COSY 2005Bad Honnef, July 25-29
2
K. Peters - Status of QCD Exotics
Overview
IntroductionStatus of Spin-ExoticsStatus of Glueball-SearchFuture Experiments
Not coveredPentaquarksBaryoniumCharmonium-Spectrum
3
K. Peters - Status of QCD Exotics
What are EXOTIC hadrons ?
Unconventional hadronsDepends on what is the convention
ConventionMatter is build out of quarks
• proton consists of 3 quarks
• pion consists of a quark and an antiquark
UnconventionalHadronic matter is not made entirely out of quarksQuark configurations different from baryons and mesons
But not forbidden !
4
K. Peters - Status of QCD Exotics
Classification (Close & Lipkin)
Exotics of the first kind
External quantum numbers unambiguously incompatible with assignment to baryons or mesons
B=1 – baryon-likeQ>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
K. Peters - Status of QCD Exotics
Classification (Close & Lipkin)
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
K. Peters - Status of QCD Exotics
Classification (Close & Lipkin)
Exotics of the third kind – Crypto-Exotics
Internal exotic structurelike gluonic excitationslike N-quarks
but no model free signature
approach:overpopulation of hadron multipletsunexpected masses and decay propertiesa well understood conventional
meson picture is mandatory 3
7
K. Peters - Status of QCD Exotics
( )14 0
( )54 8
'( )95 7
K( )49 51 S1
0
( )1300
( 1295)
'(1490 )
K( )14602 S1
0
( )1800
( )1775
K( )18303 S1
0
( )77 0
( )78 2
(10 20 )
K*( )89 21 S3
1
( )1450
( 1420)
( )1680
K *( )14102 S3
1
a 2
( )1320
a 1
( )1260
f2
( )1270
f1
( )1285
f '2
( )1525
K 2
( )1430
K 1
( )1400
b 1
( )1235
h 1( 1170)
h '1
( )1380
K 1
( )12701 P1
1
a 0
( )1450
f0
( )1370
f0
( )1710
K 0
(1430)1 P3
0
1 P31
1 P32
f2
( )1810
f '2( 2040)
K 2
( )19802 P3
2
2 P31
2 P30
2 P11
L=0 L=1
F ( )0 975
a ( )0 980
f ( )0 1515
1( )1400
1( )1600
( )1410
f ( )2 1565
f ( )2 1640
M
seen at single decayunam biguousestablished (PDG)
LEAR
notq q ?!
1 GeV/ c2
2 GeV/ c2
a 1
( )1700
a 2
(1 650)
b 1
( )1700
Meson Spectrum after the LEAR Era
The LEAR Era withthe 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
K. Peters - Status of QCD Exotics
SPIN-PARITY EXOTICS (2nd Kind)Search for Hybrids
9
K. Peters - Status of QCD Exotics
Intermediate State Mixing
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-phasesSU(3) phases
In additionalso D/S mixing (b1,a1 decays)
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K. Peters - Status of QCD Exotics
Simplest Hybrids
S-Wave+Gluon (qq)8g with ()8=coloured1S0 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
gMIX
gFSI
q
q
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K. Peters - Status of QCD Exotics
Fluxtube Predictions
N. Isgur, R. Kokoski und J. Paton, Phys. Rev. Lett. 54 (1985) 869 and refs thereinF.E. Close und P. R. Page, Nucl. Phys. B443 (1995) 233
(u,d)g
(n,s)g
ccg
12
K. Peters - Status of QCD Exotics
Light-quark hybrids
recent new determination of exotic 1-+ hybrid mesonimproved staggered fermions (lighter quark masses)quenched and unquenched, Wilson gluon actiona ~ 0.09 fmlightest mass still
above experiment
MILC, hep-lat/0301024
quenched continuum limit
sduf mmmN ,3
sdu mmm 4.0(around strange quark mass)
13
K. Peters - Status of QCD Exotics
Rediscovery of the 1(1400)
peak @ 1.4 GeV/ cphasem otion at a tail visible
2
2
B N LE 852
B N LE 852
^ ( ) 1400
Advantage: I = 1 and no S calars
GeV / c2 4
Ge
V/c
24
m ( )
m(
)
1.
1.
2.
2.
3.( )770
a2( )1320
^ ( ) 1400
Cr ystalB ar r el
52.500 E.
πp π-η p (and π0η n) pd π-π0η p @ Rest in liq.D2
14
K. Peters - Status of QCD Exotics
Proof of evidence for exotic wave - CB
Posit ive (F it - D at a)
Ne g a tive
2 (F it - D at a)
5
5
no 1 in F it
1 in F it
2
a2
a2
a2
a2
0 1
1
2
2
3
3
GeV / c2 4
GeV / c2 4
0 1
1
2
2
3
3
GeV / c2 4
GeV / c2 4
0 1
1
2
2
3
3
GeV / c2 4
GeV / c2 4
0 1
1
2
2
3
3
GeV / c2 4
GeV / c2 4
Cr ystalBar r el
15
K. Peters - Status of QCD Exotics
Controversary in E852
FSI Description in ηπ-
Szczepaniak, et al., PRL 91, 092002 (2003)
16
K. Peters - Status of QCD Exotics
Controversary in E852, cont‘d
in E852 in ηπ0
the amplitudes are different for different regions
BW solution fails
17
K. Peters - Status of QCD Exotics
π1(1400) Summary
1400 MeV/c2 region well establishedphase motion against a2(1320) in πp
interference with ρ(770) in pd @ rest
signal in πη is at b1π and f1π thresholdinfluences resultsline shapes and pole positions affected
exotic wave is evidentit might span over a wide rangeis it a Hybrid? probably not – decuplet state?
18
K. Peters - Status of QCD Exotics
E852 ρπ
BN LE 852
1
(X - 1 )- +
2
1 (I =1) 1 (I =1)
2
2 f 2
0 f 0
π-p π-ρ0p π-π-π+pshows a clear resonance in the 1-+ wave around 1600 MeV/c2
19
K. Peters - Status of QCD Exotics
VES η‘π
resonant structurein 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
Verificationof πη(') resultsin ρπ channel
ρ(16xx) observedby two independentexperiments in ρπand η‘π
V E S
1
(2 - 1 )++ - +
V ES , H adron ‘95 /’97
V E SI ( J ) = 1 (1 )G PC - - +
1(14 0 0 )
1(16 0 0 )
E852
20
K. Peters - Status of QCD Exotics
E852 f1π and b1π
blue one 1-+ poleblack two poles2=70.6/47=1.5
E852
E852
E852
21
K. Peters - Status of QCD Exotics
E852 more b1π
first observation of a non 1-+ exotic
h2(1950) with JPC=2+-
M=1954±8Γ=138±3
another h2 may be at M=2300
22
K. Peters - Status of QCD Exotics
Spin-exotic Summary
thanks to G. Adams, RPI
23
K. Peters - Status of QCD Exotics
Charmed Hybrids
LQCD: gluonic excitations of the quark-antiquark-potential may lead to bound states-potential
• for one-gluon exchange-potential
• from excited gluon flux
mHcc ~ 4.2-4.5 GeV/c2
Light charmed hybridscould be narrow if open charm decays are inaccessible or suppressed
important <r2> and rBreakup
3
3.5
4
1 2
R/r0
V(R)/GeV
J/ψ
χc
ψ‘
Hcc
DD
24
K. Peters - Status of QCD Exotics
GLUEBALLS(usually 3rd Kind)
25
K. Peters - Status of QCD Exotics
SU(N) Glueballs on the Lattice
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) 034509Morningstar und Peardon, PRD56 (1997) 4043
26
K. Peters - Status of QCD Exotics
f0(1500) – Crystal Barrel @ LEAR
f0(1500) is very narrow (~100 MeV/c2) and decays dominantly to (2n)π
und p 2 @ Ruhep 0 p 3p 0
GeV
/c2
4
G eV / c2 4
m ( )2 1 2 m ( )2
m(
)2
1
3
m(
)2
712.000 E.
1.
2.
3.
1. 2. 3.
f (1350)0
f (1500)0
f (1550)2
f (1270)2
f (975)0
C B , A ker et a l., P LB 260(1991)249C B , A m sle r et a l., PLB 342(1995)433
f ( 1350)0
f ( 1500)0
a (980)0
a (980)0
211.000 E .MeV / c2 4
MeV / c2 4
C B , A m sle r et a l., PLB 291(1992)347C B , A m sle r et a l., PLB 353(1995)571
K*
K*
1500 MeV
ein K beobachtetein K durch fehlende Masse
L
L
p p K KL L0
m (K )/GeV /2 0 2 4L c
m(K
)/G
eV/
20
24
Lc
02.55
7.510
12.515
17.520
22.5
1550 1600 1650 1700m(,) MeV
Einträ
ge
2300
2400
2500
2600
2700
2800
2900
3000x 103
1200 1300 1400 1500 1600 1700x 10
3m(0,)2
/MeV
/c24
m(, )2
/MeV/c2 4
m( ')
p ’p
m(4 )
p 5p
27
K. Peters - Status of QCD Exotics
fj(1710) in radiative J/ decays
Mark III and DM2found a scalar resonance @ 1700 MeV/c2
in KK in radiative decays of the J/
It took more than a decade to establish the scalar nature of this object
DM2
MarkIII
28
K. Peters - Status of QCD Exotics
SOZI - DOZI - Analysis
SOZI DOZI
DOZISOZI
MarkI I I
f0(1500) in 4π and
fj(1710) in KK
.........“DOZI”-enhanced
......... both should contain remarkable gg content
J /
c
c
G
J /
c
c
J /
c
c
f,f' (q )q
S OZI
DOZI suppression forconventional qq
29
K. Peters - Status of QCD Exotics
Central Production
CERN-experiments:WA76, WA91, WA102Important results in the
scalar (ππ,KK,KsKs,4) tensor (ππ,KK,KsKs,4)pseudoscalar (KKπ,ππη) sectors
But: ~ 1/M2
no charm-sectorpartial wave (moment)-
analysis complicated little фф,ωω statistics
Future:Compass, much
higher statistics
Pomeron-Pomeron
N
P
PSee-Quark-Formation
N
N
30
K. Peters - Status of QCD Exotics
Meson Glueball Mixing
Physical Massesf0(1370),f0(1500),f0(1710)
Bare Masses:m1,m2,mG
( )uu dd
2
+
ss
(G) (S) (N)f0(1370) -0.690.07 0.150.01 0.700.07f0(1500) -0.650.04 0.330.04 –0.700.07f0(1710) 0.390.03 0.910.02 0.150.02
m1=137720 m2=167410 mG=144324
octet piece
Lattice of about 1600
31
K. Peters - Status of QCD Exotics
Anisovich & Sarantsev
Anisovich and Sarantsev, hep-ph/0204328
K-Matrix approach M= 280 – 1900 MeV
Uses data from GAMS at small and large nucleon momentumE852CERN-Munich scatteringCrystal Barrel
For the channels ππ, ηη, ηη‘, KK, ππππNo f0(600) = σ
Found f0(980), f0(1300), f0(1500),
f0(1750) and f0(1200-1600)
32
K. Peters - Status of QCD Exotics
DS+ π+π-π+ (+c.c)
E791
BaBar
E.M. Aitala et al., PRL 765 (2001)
B. Lewandowski, Proc. Meson 2002PHD Th. Deppermann, Bochum 2003
848 E.
2903 E.PRELIMINARY
DDS
non-unitary approach needs interference of 4 resonances for the strange peak K-Matrix approach resolves it
33
K. Peters - Status of QCD Exotics
D+ π+π-π+ (+c.c)
E791E.M. Aitala et al., PRD 770 (2002)
1172 E.
non-unitary approach yields 50% σ K-Matrix approach removes any σ contribution
34
K. Peters - Status of QCD Exotics
Problems in Analysis and Interpretation
many processes, therefore no trivial production amplitude
coupled channels contain very many production amplitudes
complicated interferences
in K0SK0
S contr. from K0K0 and K0K0
direct FSI
directFSI
directFSI
+
Wc
s_
s
s_
Wc
s_ s
_s
I=0, KK* or c.c._
no only K0K0*+c.c.Wc
s_
s_
s_DCS
W
c
s_
s_
s
ColorS
35
K. Peters - Status of QCD Exotics
The scalar particles
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 arrangementsa00(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
K. Peters - Status of QCD Exotics
Scalar Summary
Puzzle still unsolved ....
37
K. Peters - Status of QCD Exotics
KK
’
4
4
re vie w
K* K*
NN
1.8 2.2
100
200
300
M
2.0
f (19 2 0 )2
f (18 10 )2
f (19 8 0 )2
(2 2 3 0 )
f (2 3 5 0 )2f (2 2 0 0 )2
f (2 0 5 0 )2
1.8
2.2
100
200
300
M
G .I.-Sta te s
0 ?+ +
2.0
2 GeV Tensors
Sorted by measured final state
Structure unclear
38
K. Peters - Status of QCD Exotics
f2(1920)
1.6 2.0 2.4GeV/c2
600
400
200
1.6 2.0 2.4GeV/c2
1.6 1.8 2.0
100
200
300
GeV/c2
GAMS
VES
cos <0.5
cos >0.5
all p cex.-
’
’ ’
t<0.06 0.2<t<0.35
0.35<t<0.6
39
K. Peters - Status of QCD Exotics
f2(2200)
MarkI I I
rad. J /
K KS S4K±
K K 2K±L S
MarkI I I
rad. J /
K KS S4K±
K K 2K±L S
c. prod.
t<0.06
GAMS
Broad resonanceat 2.2 GeV/c2
L3
K KS S
40
K. Peters - Status of QCD Exotics
SUMMARY and OUTLOOK I
Hybrids
Many Spin-Parity Exoticsπ1(1400) ***
π1(1600) ****
π1(2000) **
h2(1950) *
h2(2300) (*)
Future investigationsGlueX for the light quark sectorPanda for the onia and heavy light sector
41
K. Peters - Status of QCD Exotics
SUMMARY and OUTLOOK II
Glueballs
Too many scalars with an unclear natureexperimental situation fairly good, saturatedD(s)-decays can not help solving this issue
Many unconfirmed tensorsimportant field for the future to settle the spectrumBESIII and Panda are well suited
42
K. Peters - Status of QCD Exotics
FUTURE EXPERIMENTS
43
K. Peters - Status of QCD Exotics
pion
π-p X0n
exotic/non-exotic ~ 1exotic/non-exotic ~ 0.1
Szczepaniak & Swat (01)
photon
γp X+n
Possible narrow QCD exotic (M=1.6 GeV) (E852 π-p π+π-π-p)
Implications for exotic meson searches
44
K. Peters - Status of QCD Exotics
CHL-2CHL-2
Upgrade magnets Upgrade magnets and power and power suppliessupplies
Hall D @ JLab and the 12 GeV Upgrade
Construction start - 200?Physics - 200?+4
45
K. Peters - Status of QCD Exotics
The GSI Future Facility
Panda
Existing GSI Facilities
46
K. Peters - Status of QCD Exotics
0 2 4 6 8 12 1510
p Momentum [GeV/c]
Mass [GeV/c2]
Two bodythresholds
Molecules
GluonicExcitations
qq Mesons
1 2 3 4 5 6
Hybrids
Hybrids+Recoil
Glueball
Glueball+Recoil
ΛΛΣΣΞΞ
ΛcΛc
ΣcΣc
ΞcΞc
ΩcΩcΩΩ DDDsDs
qqqq ccqq
nng,ssg ccg
ggg,gg
light qqπ,ρ,ω,f2,K,K*
ccJ/ψ, ηc, χcJ
nng,ssg ccg
ggg
Accessible Charmed Hadrons at PANDA @ GSI
Other exotics with identical decay channels same region
conventionalcharmonium
exoticcharmonium
47
K. Peters - Status of QCD Exotics
BES III @ BEPC2
BEPC2 will operate as τcf and synchrotron light source
Start of operation 2007
Beam energy 1 – 2.1 GeV
Optimal energy 1.89 GeV
Luminosity 1 x 10 33 cm-2s-1 @ 1.89 GeV
Linac requirements Full energy injection: 1.55 1.89 GeV Positron injection rate > 50 mA/min
Dedicated SR 250 mA @ 2.5 GeV
48
K. Peters - Status of QCD Exotics
BES III Physics Performance Example
J/ψρ0ηπ0
Well identified ρ(1390) ρ(2300)via partial waveanalysis