Hadronic States with Large Multiquark Component Bing-Song Zou ( Institute of High Energy Physics, CAS, Beijing )

SU(3) 3q-quark model for baryons 1/2 + spin-parity 3/2 + n(udd) p(uud) -(dds) 0 (uds) 0 + (uus) -(dss) 0(uss) (sss) △0 △- △+ △++ 0 *- *+ (ddd) (udd) (uud) (uuu) (dds) (uds) (uus) *- *0 (uss) (dss) - 1232 1385 1530 1672 Successful for spatial ground states ! Prediction m- 1670 MeV experiment m- 1672.45 0.29 MeV

An outstanding problem for the classical 3q model Mass order reverse problem for the lowest excited baryons uud (L=1) ½ - ~ N*(1535) should be the lowest uud (n=1) ½ + ~ N*(1440) uds (L=1) ½ - ~ L*(1405) harmonic oscillator ( 2n + L + 3/2 ) hw To understand the full baryon spectroscopy, it is crucial to understand the lowest 1/2- baryon nonet and decuplet first !

Nature of N*(1535) and its 1/2- nonet partners `q `q ½+ [ud] }L=1 u d `q S `q ½ - [ud] [us] }L=0 Zhang et al, hep-ph/0403210 N*(1535) ~ uud (L=1) + e [ud][us]`s + … N*(1440) ~ uud (n=1) + x [ud][ud]`d + … L*(1405) ~ uds (L=1) + e [ud][su]`u + … N*(1535): [ud][us]`s  larger coupling to Nh, Nh’, Nf & KL, weaker to Np & KS, and heavier ! B.C. Liu, B.S. Zou, PRL96 (2006) 042002; PRL98 (2007) 039102

The new picture for the 1/2- nonet predicts： L* [us][ds]`s ~ 1575 MeV S* [us][du]`d ~ 1360 MeV very different from X* [us][ds]`u ~ 1520 MeV 3q model predictions Capstick 3q model Isgur 3q model

} SU(3) breaking } SU(3) allowed J/y decay branching ratio * 104 `p D(1232)+ 3/2+ < 1 `S- S(1385)+ 3.1  0.5 `X+ X(1530)- 5.9  1.5 `p N*(1535)+ 1/2- 10  3 `S- S(1360)+ ? `X+ X(1520)- ? It is very important to check whether under the S(1385) and X(1520) peaks there are 1/2 - components ? Presumed 3/2 + Sc* and Xc* should also be checked. } SU(3) breaking } SU(3) allowed

Nature of D*(1620) and its 1/2- 10-plet partners J.J.Xie, B.S.Zou, PLB649 (2007) 405 D*(1620)  ppN & ppnK+S+ extra-ordinary strong coupling of D*(1620) to rN  D*(1620) ½- rN molecule ? 1705 MeV S*(1750) ½- K*N molecule ? 1820 MeV X*(1950) ½-? K*L molecule ? 2010 MeV W*(2160) ½-? K*X molecule ? 2215 MeV 1/2- baryon decuplet ~ V8B8 molecules ?

`qqqqq in S-state seems more favorable Conclusion `qqqqq in S-state seems more favorable than qqq with L=1 ! 1/2- baryon nonet ~`qq2q2 state + … 1/2- baryon decuplet ~ V8B8 molecules + …

Similar problem for the lowest excited mesons `qq 3P0 or `q2q2 nonet ? f0(980) `ss , [`u`s ] [us] + [`d`s ] [ds] k(800) `sd , [`s`u ] [ud ] f0(600) `uu +`dd , [`u`d ] [ud] a0(980) `uu -`dd , [`u`s ] [us] - [`d`s] [ds] w(782) `uu +`dd r(770) `uu -`dd K(892) `sd f(1020) `ss `qq 3S1 nonet D*s0(2317) ~`sc (L=1) + [`q`s ] [q c] + DK + … D*s1(2460) ~`sc (L=1) + D*K + … X(3872) ~`cc (L=1) + [`q`c ] [q c] + D*D + …

A possible way to distinguish the nature of a0/f0 a0(980)-f0(980) mixing

No firm direct observation of a0-f0 mixing available ! Estimations from relevant measured parameters Model predictions `KK `q2q2 `qq For a very recent prediction from chiral unitary approach, cf. Hanhart, Kubis & Pelaez, arXiv:0707.0262  No firm direct observation of a0-f0 mixing available !

109 J/y events with BES3 detector + J.J.Wu, Q.Zhao & B.S.Zou, PRD75(2007)114012 : 109 J/y events with BES3 detector + BR(J/y  f f0  f a0  f hp ) ~ (2-20)*10-6 narrow 8 MeV peak ( 987.4 – 995.4 ) MeV Clear & precise determination of a0-f0 mixing !

J/y  fhp a0-f0 mixing BG contributions BR: a0-f0 mixing ~ (2-20)*10-6 , g* ~ 2.6*10-7 , K*K ~ (3.8 -12)*10-6

The lowest L=1 light hadronic states have Conclusion `q`q q q in S-state seems more favorable than`qq with L=1 ! The lowest L=1 light hadronic states have large multi-quark component . How about higher excited states ? Thank you !

 `d –`u ~ 0.12 Evidence for components other than 3q in the proton Deep Inelastic Scattering (DIS) + Drell-Yan (DY) process  `d –`u ~ 0.12 Garvey&Peng, Prog. Part. Nucl. Phys.47, 203 (2001) Meson cloud picture: Thomas, Speth, Weise, Oset, Brodsky, Ma, … | p > ~ | uud > + e1 | n ( udd ) p+ (`du ) > + e2 | D++ ( uuu ) p- (`ud ) > + e’ | L (uds) K+ (`su ) > … Penta-quark picture : Riska, Zou, Zhu, … | p > ~ | uud > + e1 | [ud][ud]`d > + e’ | [ud][us]`s > + …

Strange properties of N*(1535) From relative branching ratios of J/y  p`N*  p (K-`L) / p (`ph) gN*KL /gN*ph /gN*Np ~ 2 : 2 : 1 B.C. Liu, B.S. Zou, PRL96 (2006) 042002; PRL98 (2007) 039102 Evidence for large gN*Nh’ from g p  p h’ M.Dugger et al., PRL96 (2006) 062001

BES Collaboration, H. B. Li, B. S. Zou, H. C. Chiang, G. X. Peng, J. X BES Collaboration, H.B.Li, B.S.Zou, H.C.Chiang, G.X.Peng, J.X.Wang, J.J.Zhu, Phys. Lett. B510 (2001) 75

N*(1535) in J/y  p K-`L + c.c. Nx Nx Events/10MeV Nx (Arbitrary normalization) PS, eff. corrected Nx BES, Int. J. Mod. Phys. A20 (2005)

Evidence for large gN*KL from pp  p K+ L Total cross section and theoretical results with N*(1535), N*(1650), N*(1710), N*(1720) B.C.Liu, B.S.Zou, Phys. Rev. Lett. 96 (2006) 042002 pp  p K+ L Tsushima,Sibirtsev,Thomas, PRC59 (1999) 369, without including N*(1535)

FSI vs N*(1535) contribution in pp  p K+ L B.C.Liu & B.S.Zou, Phys. Rev. Lett. 98 (2007) 039102 (reply) A.Sibirtsev et al., Phys. Rev. Lett. 98 (2007) 039101 (comment) COSY-TOF data S. Abdel-Samad et al., Phys.Lett.B632:27(2006) FSI N*(1650) etc. Both FSI & N*(1535) are needed !

Evidence for large gN*KL from g p  K+ L B. Julia-Diaz, B. Saghai, T.-S.H. Lee, F. Tabakin, Phys. Rev. C 73, 055204 (2006)

G.Penner&U.Mosel, PRC66 (2002) 055212 Partial wave decomposition For the fit to SAPHIR92-94 Data Dashed line : 1/2 - Dot-dashed line : 3/2+ Shklyar,Lenske&Mosel, PRC72 (2005) 015210

Evidence for large gN*Nf from p- p  nf & pp  ppf Xie, Zou & Chiang, arXiv:0705.3950 pp  ppf r-ex h-ex p-ex with FSI no FSI p- p  nf Evasion of OZI rule by N*(1535) !

Evidence for small gN*KS from pp  p K+L /pp  p K+S0 A.Sibirtsev et al., EPJA29 (2006) 363 [2] P.Kowina et al., EPJA22 (2004) 293

Pentaquark vs Meson Cloud Weise, Oset et al: N*(1535) as K L-KS state, L*(1405) as KN state `S u S d u d `S S Pentaquark vs Meson Cloud More solid information on its coupling to KS and its 1/2- octet partner are needed !

Role of D++*(1620) in ppnK+S+ J.J.Xie, B.S.Zou, PLB649 (2007) 405 Why D++* ? uuu -- the most experimentally accessible system with 3 identical valence quarks -- suggested the color degree of freedom in 1960s Why D++* (1620) ? JP = ½ - -- The lowest excited uuu state with L=1 in classical 3q models

Our present knowledge on D++* resonances Why ppnK+S+ ? Our present knowledge on D++* resonances mainly comes from p+p experiments and is still very poor. D*++ p p +, r + n S+ K+ ppnK+S+ -- D++* production from r+p -- accessible at COSY and CSR

Status on the study of ppnK+S+ -- New COSY-11 data Resonance model Incohenrent p/K exchange model also fails to reproduce these data

Our calculation for ppnK+S+ D*++(1920) with p+ exchange D*++(1620) with r+ exchange D*++(1620) with p+ t-channel r-exchange plays important role !