Institute of High Energy Physics -- Beijing --

Near-threshold non-qq meson candidatesStephen Lars OlsenSeoul National University_Heavy-Quark Hadrons at J-PARC Symposium at Tokyo Inst. Tech., June 22,2012 2Constituent Quark Model1964 The model was proposed independently by Gell-Mann and Zweig with three fundamental building blocks: 1960s (p,n,l) 1970s (u,d,smesons are bound states of a of quark and anti-quark:baryons are bound state of 3 quarks:

Gell-Mann

Zwieg

Google Search: quark: 41,000,000 results (0.13 seconds)Fabulously successfulQuarks are probably the mostwell known particle physics quantityamong the general public

: 2,600,000 results (0.65 seconds) Superseded by QCD in the 1970s:observed particles are color singlets4

= (uds)

Mesons are color-anticolorpairsBaryons are red-blue-green triplets

3 primary colors white whitecolor + complementary color blue-yellowgreen-magentared-cyan QCD has other color-singlet combinations:Pentaquark:H-diBaryon

Glueball

Tetraquark mesons

qq-gluon hybrid mesons

ucuc

ccudusdOther possible white combinations of quarks & gluons:____udusds__ucuc___pD0D*0_S=+1 Baryontightly bound6-quark stateColor-singlet multi-gluon bound statetightly bounddiquark-diantiquarkloosely boundmeson-antimesonmoleculeWhere are they?

ucuc

ccudusd____udusds_ucuc___pD0D*0_some history: low-mass scalar mesonsThe light scalar mesons

JP=0+800980a0-a0+k+k0a00sf0600800800800980k-k0980_ the light scalar-meson nonetMore light scalar-mesons than quark model slots: s, f0(980), f0(1370), f0(1500), f0(1710), f0(1790), light scalar nonet: masses are inverted In qq meson nonets, the I=1 state (here the a0(980)) has no ss content.

No light JP=1+ and 2++ partner nonets in the same mass range.__pseudoscalarsscalarstypicaluniquess-quark content_If not qq, then what?_sqs__qsqs___sKK_tightly bounddiquark-diantiquarkloosely boundmeson-antimesonmoleculeqPossibilities that have been suggested:J.D.Weinstein & N.Isgur PRD 27, 588 (1983)

R.L.Jaffe PRD 15, 267 (1977)In color space:red+blue=magenta (antigreen)cyan+yellow=green (antimagenta)A colored diquarkis like a antiquarkA colored diantiquarkis like a quarknuclear forceInstitute of High Energy Physics-- Beijing --

To Tiananmen Square (~10 km)BESIIIBEPC11BEPCII storage rings

Beam energy: 1.0 - 2.3 GeVPeak Luminosity: Design:11033 cm-2s-1Achieved:0.65x1033 cm-2s-1Beam energy measurement: Using Compton backscattering technique. Accuracy: dEbeam/Ebeam 510 5 dEbeam 50 KeV @Ebeam mt

BESIII Collaboration

>300 physicists 49 institutions from 10 countries 11Turkey: Turkish accelerator center Helmholtz Institute Mainz Johannes Gutenberg-University Mainz 29

The a0(980) & f0(980) straddle the KK threshold

a0(980) (hp0)2mK

f0(980) K+K-f0(980) p+p-2mK_a0(980)0 f0(980) mixing

isospin violation enhanced by K0 K+ mass difference 2mK+ = 987.4 MeV2mK0 = 995.2 MeV

2mK+ 2mK0 expect a narrow line shape: G2(mK0-mK+)=7.8 MeV PDG2010: Mf0= 980 10 MeV f0= 40 ~ 100 MeV

Ma0= 980 20 MeV a0= 50 ~ 100 MeV

N.N. Achasov, S.A. Devanin & G.N. Shestakov, Phys. Lett. B88, 367 (1979)BES study of a0(980)0 f0(980) mixing

BESIII PRD 83, 032003 (2011)a0(980)0 f0(980) mixing results

different models &parameterizationsKK molecule model_90% CL upper limitsStatistics limited, but BESIII already has lots more data.J/f0(980)p0,f0(980)pp

f0(980)00f1(1285)3.7sf1(1285)1.2sf0(980)+-h(1405)h(1405)Large Isospin violations:from helicity analyses

1st observations: (1405)f0(980)p0 & J/ygf0(980)p0

BESIII PRL 108, 182001 (2012)Anomalous f0(980) lineshape in h(1405)f0(980)p0

Fitted mass: Mf0 = 989.9 0.4 MeVf0 = 9.5 1.1 MeVThe peak is midway between 2mK0 & 2mK+ & width 2(mK0 - mK+ ) PDG2010: Mf0= 980 10 MeV f0=40 ~ 100 MeV BESIII PRL 108, 182001 (2012)Effect of Triangle Singularity?J.J.Wu et al, PRL 108, 081803 (2012)

Triangle Singularity (TS)a0f0 mixingK*K and KK are on shellenhancing TS contributionand isospin violation __a0f0 mixing is too small toexplain anomaly by itselff0(980) and h(1405) strongly influenced by the nearby KK & KK* thresholds.__h(1405)Baryonium at the pp threshold?_J/y g pp @BESII

This is the hcppthe J/ysspin=0 partnerWhat is this???M(pp) GeVBESII PRL 91, 022001 (2003)Fit the M(pp) distribution

fit with a sub-threshold resonance_M(pp) GeV

Mpp-2mp (GeV)00.10.20.3BESII PRL 91, 022001 (2003)M=1859 MeV/c2

G < 30 MeV/c2 (90% CL) +3 +5-10 -25cartoonreal fitX(1835) has large BR to ppBESIII:

our estimate from unpublished Crystal Ball data:implies a huge Br(Xpp):

Since decays to pp are only possible from the tail of X(1835), such a BR indicates X(1835) has a huge coupling to pp !

J/y g XXtal Ball(unpublished)see L.Kopke, N.Wermes,Phys. Rep 174, 67 (1989)23X(3872) meson near the DD* threshold_KEK Laboratory, Tsukuba Japan

Fukushima

Belle Detectore-e+

KEKBMt Tsukubacc meson production in B decaysd1/3b-1/3C-2/3C+2/3d1/3S-1/3W-K0CharmoniumspectatorB0___Belles main purpose: Measure CP violations with B mesons that decay like this. Nobel prize for Kobayashi &Maskawa in 2008Charmonium (cc) meson spectrum_All of the states below 2mDhave been identifiedThe X(3872) in BK p+p-J/y discovered by Belle (140/fb)

M(ppJ/y) M(J/y)yp+p-J/yX(3872)p+p-J/yPRL 91, 262001 (2003)X(3872)p+p- J/yconfirmed by many experiments

~6000 evts!MX = 3871.61 0.16 0.19 MeV MX = 3871.85 0.27 0.19 MeV

MX = 3871.96 0.46 0.10 MeVCDF LHCb Belle: PRD 84 052004CDF: PRL 103 152001LHCb: arXiv:1112.5310

Belle

p+p-system in X(3872)p+p-J/y comes from rp+p-X3872rp+J/yp-CDF: PRL 96 102002

M(p+p- )

M(p+p- )rp+p- lineshapeBelle: PRD 84 052004Problem: (cc)r J/y violates Isospinand should be strongly suppressed_X(3872) not well matched toany unassigned cc level 3872 MeV_

X(3872) mass (in p+p-J/y channel only)MX(3872) (MD0 + MD*0) = -0.12 0.35 MeV_MD0+MD*0=3871.79 0.30 MeVucuc___pD0D*0_D0D*0 molecule??_Isospin Violation in X(3872) decay:on mass shell8 MeV off mass shellMX(3872) (MD+ + MD*-)= -7.74 0.35 MeVIf so, the binding energy is very smallX(3872)-J/y relative sizes How can such a fragile object be produced in H.E. pp collisions? heavy ion collisions??Volume(J/y) /Volume(X3872) 10-4-- arXiv 0906.0882: sCDF(meas)>3.10.7nb vs stheory(molecule)