Pentaquarks in Chiral Soliton Models

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Pentaquarks in Chiral Soliton ModelsPentaquarks in Chiral Soliton Models

Bo-Qiang Ma Peking University Peking University

August 17,August 17, 200 2004, Talk at ICHEP04, Beijing4, Talk at ICHEP04, Beijing

In Collaboration with B. Wu Hep-ph/0312041, PRD69(2004)077501

Hep-ph/0312326, PLB586 （ 2004 ） 62

Hep-ph/0311331, Hep-ph/0402244

Hep-ph/0408121 all to appear in PRD

Pentaquark StatesPentaquark States

• Predictions of pentaquark states with both strange and charm (by Lipkin et al.),

with no evidence found yet.

Prediction in Chiral Soliton Model

• all baryons are rotational excitations of a rigid object

• reproduces mass splittings witin 1% of

– baryon octet (JP=½+) and decuplet (JP=3/2+)

• predicts new anti-decuplet (among many Ncartifacts)

• “only one” free parameter

D. Diakonov, V.Petrov, M.Polyakov, Z.Phys.A359, 305 (1997)

Identifying P11(1710) as member of anti-decuplet:

prediction for M1.53 GeV 15 MeV

I=0 S=+1 JP=½+

K0 p or K+n

the 3 corners are exotic

pK0 or nK+

Based on older predictions:Manohar(1984); Chemtob (1984); Praszalowicz (1987)

Suggestion for the existence of higher multipletsSuggestion for the existence of higher multiplets

M.-L.Yan and X.-H.Meng, Commun. Theor. Phys. 24 (1995) 435

• The corrections to the Gell-Mann-Okubo relations of baryons masses in SU(3) Skyrmen model are considered.

• The results could be regarded as a signal for the existence of the SU(3) rotation excitation states of baryons: 10*-let, 27-plet, and 35-let.

Nothing is “Exotic” in the Chiral Solition PictureNothing is “Exotic” in the Chiral Solition Picture

• Baryons are “solitons” in the chiral meson fields.

• No baryon is “exotic” except that it has different quantum numbers compared to other baryons.

““Exotic”-baryon (Pentaquark) DefinationExotic”-baryon (Pentaquark) DefinationH.Gao and B.-Q. MaH.Gao and B.-Q. Ma

Mod. Phys. Lett. A 14 (1999) 2313Mod. Phys. Lett. A 14 (1999) 2313

• A pentaquark qqqqq state can be clearly A pentaquark qqqqq state can be clearly distinguished from the conventional qqq-baryon distinguished from the conventional qqq-baryon state or their hybrids if the flavor of q is different state or their hybrids if the flavor of q is different from any of the other four quarks: from any of the other four quarks:

minimal Fock state of pentaquarkminimal Fock state of pentaquark

• Possible existence of uudds and uuuds states are Possible existence of uudds and uuuds states are suggested.suggested.

Suggestion for search of pentaquark uudds stateSuggestion for search of pentaquark uudds statein physics processin physics process

H.Gao and B.-Q. MaH.Gao and B.-Q. Ma Mod. Phys. Lett. A 14 (1999) 2313Mod. Phys. Lett. A 14 (1999) 2313

• Suggested:n Θ

missing mass method to construct Θ

• SPring8 and CLAS experiments: sub-process

n (Kn) an additional K is detected to reduce background for the missing

mass spectrum and real photon is used instead of virtual photon.

Summary of recent experiments (incomplete list)Summary of recent experiments (incomplete list)

world-average: : 15322.4 MeV

Summary of Null Results (incomplete list)

⇒ A null result cannot be considered to be decisiveif nearby known particles of the same decay mode (pK0 or nK+) are not seen.

no evidence no evidence forfor KK++p p in HERMESin HERMES

Suggesting ++ Being Isosinglet

I=0 is likely

I=2 is ruled out

I=1 is unlikely, but cannot be

ruled out

X.Chen, Y.Mao, and B.Q.Ma,

hep-ph/0407381

Pentaquark States from Theory:Pentaquark States from Theory:anti-decuplet in chiral soliton models-1st version

Prediction of Diquark modelPrediction of Diquark model

[ud]2s

3/2(1750)

+(1530)

[us]2d[ds]2u

R.L. Jaffe and F. Wilczek, PRL91 (2003) 232003

Evidence for New Pentaquark?Evidence for New Pentaquark?

SM: M(*--) = 2070 MeV

[qiqj]2q: M(*--) = 1750 MeV

C. Alt et al., hep-ex/0310014NA49 at CERN pp *-- X, *0 X, - - - +s = 17,2 GeV

1,862 0,002 GeV

But: It is not what theory predicted !

D. Diakonov et al., hep-ph/0310212

uud ds

sdd.. sdu.. suu(dd+ss)

(1754)

3/2(1862)

+(1539)

Anti-Decuplet in Chiral Soliton ModelAnti-Decuplet in Chiral Soliton Model - Version 2

N(1647)

ssu udssd du ssd (uu+dd) ssu..

duu(dd+ss)

108 MeV

D. Diakonov and V. Petrov hep-ph/0310212

B. Wu and Ma, hep-ph/0311331, PRD

Where are the missing members of antidecuplet?Where are the missing members of antidecuplet?

• For baryons with spin ½ and + parity, there is no N around, and a weak evidence for (1770),

so Diakonov and Petro (hep-ph/0310212) suggeted a missing N around 1650-1690 MeV;

the position of N(1710) is not at M=1710 MeV, but some where around M=1650 to 1690 MeV, suggested by Arndt et al(nucl-th/0312126) .

• We noticed ( hep-ph/9311331) that there are candidates of N(1650) and (1750) with spin ½ and negative (–) parity, in PDG

This may suggest a negative parity for antidecuplet members in the chiral soliton model:

parity in chiral solition has two parts: quantized part with positive parity and classical part with unknown parity;

the collective coordinate quantization can not inevitably fix the parity of the corresponding baryons.

The width formula and the widths in the case of negative parityThe width formula and the widths in the case of negative parity

decay width is excellent for S(1750), but poor for N(1650) , possible solution:

SU(3) breaking for baryons with strangeness,

or there is a missing N resonance around 1650 with narrow width.

Theories of Theories of positivepositive parity for parity for • Chiral Soliton Models (old version) Diakonov-Petrov-Polyakov, ZPA359(1997)305

• Analysis in Quark Model Stancu-Riska, PLB575(2003)242

• Diquark Cluster Model Jaffe-Wilczek, PRL91(2003)232003

• Diquark-Triquark Model Karliner-Lipkin, PLB575(2003)249

• Inherent Nodal Structure Analysis Y.-x.Liu, J.-s.Li, and C.-g. Bao, hep-ph/0401197

• Naive Quark Model Jaffe (1976)

• Some Quark Models Capstick-Page-Roberts, PLB570(2003)185

Huang-Zhang-Yu-Zhou, hep-ph/0310040 ， PLB586(04)69.

• QCD Sum Rules Zhu, PRL91(2003)232002, Sugiyama-Doi-Oka, hep-ph/0309271

• Lattice QCD Sasaki, hep-ph/0310014, Csikor et al, hep-ph/0309090,

but we heard difference voices recently

Theories of Theories of negativenegative parity for parity for

Where is the answer? Where is the answer? Experiment!Experiment!

• Many suggestions on detecting the parity

Oh-Kim-Lee, hep-ph/0310019

Zhao, hep-ph/0310350

Liu-Ko-Kubarovsky, nucl-th/0310087

Nakayama-Tsushima, hep-ph/0311112

Thomas-Hicks-Hosaka, hep-ph/0312083 ……

• Measurement of parity is crucial to test theories

What else if I=0 or s=1/2 What else if I=0 or s=1/2

• Answer: Most theories would need revision!

Predictions of New PentaquarksPredictions of New Pentaquarks -27-plet

Figure from Wu & Ma, PRD69(2004)077501.

The mass splitting of the 27-plet The mass splitting of the 27-plet from chiral solitonsfrom chiral solitons

The widths of the 27-plet The widths of the 27-plet baryonsbaryons

SU(3) Symmetric Case

The picture of the 27-plet The picture of the 27-plet baryons:baryons:

non-exotic members are well establishednon-exotic members are well established

We suggest that the quantum numbers of is JP=(3/2)+

Many new pentaquarksMany new pentaquarks to be discoveredto be discovered

Predictions ofPredictions of

• Walliser-Kopeliovich, hep-ph/0304058

mass=1650/1690 MeV

• Borisyuk-Faber-Kobushkin, hep-ph/0307370

mass=1595 MeV, width=80 MeV

• Wu-Ma, PLB586(2004)62

mass=1600 MeV, width less than 43 MeV

Predictions of New PentaquarksPredictions of New Pentaquarks -35-plet

Figure from Wu & Ma, hep-ph/0408121, PRD, to appear

Mass splitting of 35-plet from chiral Mass splitting of 35-plet from chiral solitonssolitons

The widths of the 35-plet baryonsThe widths of the 35-plet baryons

SU(3) Symmetric Case

Prediction of Pentaquarks Prediction of Pentaquarks in SU(4) Chiral Solition Modelin SU(4) Chiral Solition Model

B.Wu and B.-Q.Ma, hep-ph/0402244,

PRD to appear

Experiment Evidence at H1Experiment Evidence at H1

hep-ex/0403017 hep-ex/0403017

The pentaquark uuddcThe pentaquark uuddc• Prediction of the mass of the ground uuddcbar: Prediction of the mass of the ground uuddcbar:

m=2704 MeV, as pD statem=2704 MeV, as pD state Wu-Ma, hep-ph/0402244Wu-Ma, hep-ph/0402244

• Observation by H1 Collaboration: m=3099 MeVObservation by H1 Collaboration: m=3099 MeV

hep-ex/0403017 hep-ex/0403017

can be considered as pD* statecan be considered as pD* state

• From M(D*-D)~300 MeV, the observed uuddcbar can be From M(D*-D)~300 MeV, the observed uuddcbar can be

considered as an excited state (chiral partner) of the considered as an excited state (chiral partner) of the

predicted ground pentaquark state predicted ground pentaquark state

M. Nowak et al, TPJU-4/2004, BNL-NTBNL-NT-04/10M. Nowak et al, TPJU-4/2004, BNL-NTBNL-NT-04/10

ConclusionsConclusions

• The reported pentaquark The reported pentaquark ++ is still not yet is still not yet

established as a member of a well-defined anti-established as a member of a well-defined anti-

decuplet in chiral soliton models.decuplet in chiral soliton models.

• The non-exotic members of 27-plet and 35-plet in The non-exotic members of 27-plet and 35-plet in

the chiral soliton models are found to exist in the the chiral soliton models are found to exist in the

available PDG listing. available PDG listing.

• There should be new pentaquark states, if the There should be new pentaquark states, if the

chiral soliton picture is correct.chiral soliton picture is correct.

Pentaquarks in Chiral Soliton Models

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