klaus peters ruhr-universität bochum jinr dubna workshop, nov … · 2006. 1. 9. · 9 klaus...

Klaus PetersKlaus PetersRuhrRuhr--UniversitätUniversität BochumBochum

JINR JINR DubnaDubna Workshop, Nov 20, 2003Workshop, Nov 20, 2003

Exotic Hadrons @ PandaExotic Hadrons @ Panda

22 Nov 20, 2003Nov 20, 2003Klaus Peters, U Bochum, Hybrids and GlueballsKlaus Peters, U Bochum, Hybrids and Glueballs

Understanding QCD at small EnergiesUnderstanding QCD at small Energies

Increase precisionmeasure static properties of well known states

Increase the database of decayssearch for unusual decay modes to gain information

Put the hadrons to the limits put the hadrons in vacuum with different baryon density

Excite additional modessearch for gluonic and radial excitations of hadronssearch for gluonic excitation of the strong vacuum


Objects of InterestObjects of Interest

Mesons/Baryons

Molecules/Multiquarks

Hybrids

Glueballs

Quark AntiQuark


1.0

1.5

2.0

2.5

qq Mesons

L = 0 1 2 3 4

Each box correspondsto 4 nonets (2 for L=0)

Radial excitations

(L = qq angular momentum)

exoticnonets

0–+

0+–

1++

1+–

1–+

1––

2–+

2+–2++

0–+

2–+

0++

Glu

eballs

Hyb

rids

Lattice1-+ 1.9 GeV

Light Meson SpectrumLight Meson Spectrum

0++ 1.6 GeV


Hybrid mixing

Glueball mixing

Level MixingLevel Mixing

Light quark problemthe mixing

Mixingbroad stateshigh level density

I=1 I=0nn I=0ss I=½

a1 f1 f1’ K1B

b1 h1 h1’ K1A

JPC=JP+

JPC=JP-

Kaon mixingstrong interaction C undefined K1A-K1B

Isoscalar mixingstrong interaction IG, JPC identical ?-?‘

Isospin mixingelm interaction ? I=1 ?-?


Level MixingLevel Mixing

Light quark problemthe mixing

Mixingbroad stateshigh level density

Better:narrow states

and/or lower level densitycharmed systems !

Exo

tic

light

qq

Exo

tic

cc

1-- 1-+

0 2000 4000MeV/c2

10-2

1

102


Σ

Π

Charmed HybridsCharmed Hybrids

LQCD: gluonic excitations of the quark-antiquark-potential may lead to bound statesΣ-potential

for one-gluon exchangeΠ-potential

from excited gluon flux

mHcc ~ 4.2-4.5 GeV/c2

Light charmed hybrids could be narrow if open charm decays are inaccessible or suppressed

Σ

Π

important <r2> and rBreakup

3

3.5

4

1 2

R/r0

V(R)/GeV

J/?

?c

? ‘

Hcc

DD


S1

S2

S=S1+S2

J=L+S

P=(-1)L+1

C=(-1)L+S

L

Simplest HybridsSimplest Hybrids

S-Wave+Gluon (qq)8g with ()8=coloured1S0 ↑↓ 3S1 ↑↑ combined with a 1+ or 1- gluon

2–+2+-

1–+1+-

0–+0+-3S1, 1––

1––1++1S0, 0–+

1+(TE)1– (TM)Gluon

Exotic JPC cannot! be formed by qq


LQCD LQCD ccccgg 11--++ vs. cvs. ccc 11---- (J/(J/ψψ))

NPB93Supp(1999)264MILC99isotropic150±4317

PRL82(1999)4400JKM99isotropic4287

±

±

±

±

37

130

150

80

m(ccg)- m(cc)

37

80

m(ccg)

hep-lat 0206012ZSU02anisotropic99±1302

PRL82(1999)4400JKM99isotropic1190

PRL82(1999)4396CP-PACS99anisotropic±1323

NPB93Supp(1999)264MILC99isotropic±1220

PRD56(1997)7039MILC97isotropic200±1340

∆(1-+,1--)

hep-lat 0206012ZSU02anisotropic99±4369

PRD56(1997)7039MILC97isotropic200±4390

ReferenceGroupModel1-+


Charmed Hybrid Level SchemeCharmed Hybrid Level Scheme

1-- (0,1,2)-+ < 1++ (0,1,2)+-

JKM, NPB 83suppl(2000)304 and Manke, PRD57(1998)3829

L-Splitting?m ~ 100-250 MeV/c2

for 1-+ to 0+-

S-SplittingsPage thesis,1995 and PRD 35(1987)16684.14 (0-+) to 4.52 GeV/c2 (2-+)

consistent w/LQCDJKM, NPB 86suppl(2000)397, PLB478(2000) 151

0-+ 4.14

1-+ 4.37

2-+ 4.52

1-- 4.48

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

0+- 4.47

1+- 4.70

2+- 4.85

1++ 4.81

DD**


FluxtubeFluxtube

Meson

Hybrid

~ Simplified Lattice Approach

Flux (excited Gluon) carries angular momentumBali, priv. comm., 1991


Charmed Hybrids Charmed Hybrids –– DecaysDecays

Fluxtube-Model predicts DD**(+c.c.) decaysif mH< 4290 MeV/c2 below DD0(+c.c.)

→ ΓH < 50 MeV/c2

Some exotics can decay neither to DD nor to DD*(+c.c.)

e.g.: JPC(H)=0+-

J/? f2, J/? (pp)S, ?ch1

χc0ω, χc0φ, χc2ω, χc2φ, h1c?Small number of final states with small phase space

favours a narrow resonanceif DD**(+c.c.) possible → still very small phase space

But! be prepared for surprisesmeasure DD nor to DD*(+c.c.) waves as well


Charmed Hybrids Charmed Hybrids –– Decays of 1Decays of 1--++

a very likely decay mode will (could?) be χc(pp)S

aC. Michael, hep-lat 0207017preferably using p0p0 to avoid ?(770) contaminationuse charged mode p+p- for comparison

detect the χc in the radiative decay to J/?

detect the soft photonand the lepton pair

NeededSerious calculations for production and partial decay widths for ccg


ProtonProton--Antiproton AnnihilationAntiproton Annihilation

Production all JPC available

Formation only selected JPC

p

p recoil

p

p


Formation

ProtonProton--Antiproton AnnihilationAntiproton Annihilation

Gluon rich process creates gluonic excitation directlyss/cc requires the quarks to annihilate (no rearrangement)yield comparable to charmonium productioneven at low momenta large exotic content has been proven

G

M

p

p

G

p

p

Production all JPC available

only selected JPC

p

p

H

nng

H

p

p ssg/ccg

M

p

p

H

nng

M

Hp

p

ssg/ccg


Heavy GlueballsHeavy Glueballs

Light gg/ggg-systems are complicated to identify (mixing!)Exotic heavy glueballs

m(0+-) = 4140(50)(200) MeVm(2+-) = 4740(70)(230) MeV

Width unknown, but!nature invests more likely in mass than in momentumnewest proof: double cc yield in e+e-

Flavour-blindnesspredicts decays into charmed final states too

Same run period as hybridsIn addition: scan m>2 GeV/c2

Morningstar,Peardon, PRD60(1999)34509Morningstar,Peardon, PRD56(1997)4043

2++

0+-

2+-


44--Quark FormationQuark Formation

Proton-Antiproton contains already a 4-Quark-System

Idea: Dilepton-Tag from Drell-Yan-Production

AdvantagesTriggerless JPC-Ambiguities1200 E./day @ 12 GeV300 E./day @ 5-8 GeVantiproton-Beam(for L=1032cm-2s-1)

Bannikov, Gornuschkin, Kopeliovich, Krumshteinand Sapozhnikov, JINR E1-92-344 (1992)


TT + + @ @ variousvarious experimentsexperimentsLEPS(SPRingLEPS(SPRing--8), 8), Diana(ITEPDiana(ITEP), ), Clas(JLABClas(JLAB) ) Saphir (Elsa)Saphir (Elsa)


PentaQuarkPentaQuark PicturePicture

In a multi quark picturenK+ has an anti-strange quark and several light quarkspKS has no defined strangeness and thus only a supporting evidence

Jaffe-Wilczek pictureAnti-quark act as a junction between two diquarks

Basic ideaReplace the anti-quark by other anti-quarks – like anti-charmseveral quark combinations for each charge

T C-- |cdddd>, |cssss>

T C- |cuddd>, |cudds>, |cudss>, |cusss>

T C0 |cuudd>, |cuuds>, |cuuss>

T C+ |cuuud>, |cuuus>

T C++ |cuuuu>

plus all isomeres

Jaffe & Wilczek hep-ph/0307341Karliner & Lipkin hep-ph/0307343


TT CC00 ||ccuudduudd>, |>, |ccuudsuuds>, |>, |ccuussuuss>>

Is the most discussed anti-charm penta-quark|cuudd> would decay to ND final states like nD0 or pD-

problematic below the ND threshold of ~2.8 GeV/c2

(many weak channels NKX possible, signature unclear)|cuuds> would decay to pDS

-

but also below the open charm threshold (~2.91 GeV/c2) there is the clean channel pφπ- which would also be used for the pDS

-

selection|cuuss> would decay to S+DS

- and ?0D0

but also below the open charm threshold (~3.15 GeV/c2) there is the clean channel S+φp- which would also be used for the S+DS

- selection.(there are some other weak channels with ?KX with unclear signature)

Implies uncooled p beam or formation with Fermi-momentumon a nuclear target


Exotics in ProtonExotics in Proton--AntiprotonAntiproton

Exotics are heavily produced in pp reactions

High production yields for exotic mesons (or with a large fraction of it)

f0(1500)p → ~25 % in 3p0

f0(1500)p → ~25 % in 2?p0

p1(1400)p → >10 % in p±p0?

Interference with other well known (conventional) states is mandatory for the phase analysis

Crystal Barrel


0 2 4 6 8 12 1510p Momentum [GeV/c]

Mass [GeV/c2]

Two bodythresholds

Molecules

GluonicExcitations

qq Mesons

1 2 3 4 5 6

Hybrids

Hybrids+Recoil

Glueball

Glueball+Recoil

??SS??

? c? cScSc? c?c

OcOcOO DDDsDs

qqqq ccqq

nng,ssg ccg

ggg,gg

light qqp,?,? ,f2,K,K*

ccJ/? , ?c, ?cJ

nng,ssg ccg

ggg

Accessible Hadrons at PANDA @ GSIAccessible Hadrons at PANDA @ GSI

conventionalcharmonium

exoticcharmonium

Charmed states


0 2 4 6 8 12 1510p Momentum [GeV/c]

Mass [GeV/c2]

Two bodythresholds

Molecules

GluonicExcitations

qq Mesons

1 2 3 4 5 6

Hybrids

Hybrids+Recoil

Glueball

Glueball+Recoil

??SS??

? c? cScSc? c?c

OcOcOO DDDsDs

qqqq ccqq

nng,ssg ccg

ggg,gg

light qqp,?,? ,f2,K,K*

ccJ/? , ?c, ?cJ

nng,ssg ccg

ggg

Accessible Hadrons at PANDA @ GSIAccessible Hadrons at PANDA @ GSI

Other exotics with identical decay channels → same region

glueballs

Glueballs


Lessons from LEARLessons from LEAR

Eγ

3π0

Emin

cosθ

Full solid angleno missing particles (photons!)no “dead” regions

Merged p0 are easy to handle“moderate” angular resolution sufficient

Low thresholdsEmin~20 MeV in theelectromagnetic detector

φ (φ)-Tagφφ and recoil φ

K-Trigger/K-IdKS-TriggerKaon ID @ high energies


It’s All a Question of Statistics ...It’s All a Question of Statistics ...

pp → 3p0

with100 events


It’s All a Question of Statistics ... ...It’s All a Question of Statistics ... ...

pp → 3p0

with100 events1000 events


It’s All a Question of Statistics ... ... ...It’s All a Question of Statistics ... ... ...

pp → 3p0

with100 events1000 events10000 events


It’s All a Question of Statistics ... ... ... ...It’s All a Question of Statistics ... ... ... ...

pp → 3p0

with100 events1000 events10000 events100000 events


pp in Flight in Flight –– no longer a challenge!no longer a challenge!

Crystal Barrel provedannihilation in flight can be analyzed unambiguously

Formation:two body decays, where at least one particle carries spin!~10k events L up to 6

Production:small recoil momenta reduce the available phase space and the contributing waves dramaticallyalternative: integration of the production process

Peters, NPA 692(2001)295


Summary & OutlookSummary & Outlook

Investigation of exotics is thekey tool for the investigation ofgluonic degrees of freedom inside hadrons

Panda@HESR will survey the mass region from ~2 to more than 4 GeV/c2 in formation and production processes ...

... to measure the whole spectrum of heavy exotics

klaus peters ruhr-universität bochum jinr dubna workshop, nov … · 2006. 1. 9. · 9 klaus...

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