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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
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Pentaquark StatesPentaquark States
• Predictions of pentaquark states with both strange and charm (by Lipkin et al.),
with no evidence found yet.
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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+
with
K0 p or K+n
the 3 corners are exotic
or or
pK0 or nK+
Based on older predictions:Manohar(1984); Chemtob (1984); Praszalowicz (1987)
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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.
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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.
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““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.
-
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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.
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Summary of recent experiments (incomplete list)Summary of recent experiments (incomplete list)
world-average: : 15322.4 MeV
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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.
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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
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Pentaquark States from Theory:Pentaquark States from Theory:anti-decuplet in chiral soliton models-1st version
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Prediction of Diquark modelPrediction of Diquark model
[ud]2s
*0
*- *0
S
I3
3/2(1750)
+(1530)
1-1
-1
1
[us]2d[ds]2u
R.L. Jaffe and F. Wilczek, PRL91 (2003) 232003
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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
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uud ds
sdd.. sdu.. suu(dd+ss)
*0
*- *0
S
I3
(1754)
3/2(1862)
+(1539)
Anti-Decuplet in Chiral Soliton ModelAnti-Decuplet in Chiral Soliton Model - Version 2
1-1
-1
N(1647)
ssu udssd du ssd (uu+dd) ssu..
duu(dd+ss)
sdu..
1
108 MeV
D. Diakonov and V. Petrov hep-ph/0310212
B. Wu and Ma, hep-ph/0311331, PRD
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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.
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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.
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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
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• 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
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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
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What else if I=0 or s=1/2 What else if I=0 or s=1/2
• Answer: Most theories would need revision!
//
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Predictions of New PentaquarksPredictions of New Pentaquarks -27-plet
Figure from Wu & Ma, PRD69(2004)077501.
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The mass splitting of the 27-plet The mass splitting of the 27-plet from chiral solitonsfrom chiral solitons
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The widths of the 27-plet The widths of the 27-plet baryonsbaryons
SU(3) Symmetric Case
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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)+
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Many new pentaquarksMany new pentaquarks to be discoveredto be discovered
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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
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Predictions of New PentaquarksPredictions of New Pentaquarks -35-plet
Figure from Wu & Ma, hep-ph/0408121, PRD, to appear
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Mass splitting of 35-plet from chiral Mass splitting of 35-plet from chiral solitonssolitons
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The widths of the 35-plet baryonsThe widths of the 35-plet baryons
SU(3) Symmetric Case
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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
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Experiment Evidence at H1Experiment Evidence at H1
hep-ex/0403017 hep-ex/0403017
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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
__
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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.
