Penta-quarks at J-PARC K. Imai (Kyoto) Introduction Width and - PowerPoint PPT Presentation

K.Imai: JPARC-WS K.Imai: JPARC-WS 04/5/8 (KEK) 04/5/8 (KEK) Penta-quarks at J-PARC K. Imai (Kyoto) • Introduction • Width and spin-parity of Θ + and E559 at KEK-PS • Exotic hadron spectroscopy at J-PARC • Summary

Discovery of Pentaquark Θ + Μ = 1540 ± 10 MeV Γ < 25 MeV SPring-8 LEPS Gaussian significance 4.6 σ • γ +n -> K - +K + +n, Θ + -> K + n 15 Θ + : uudd s-bar Events/(0.02 GeV/c 2 ) 10 T. Nakano et al., 5 Phys.Rev.Lett. 91 (2003) 012002 background hep-ex/0301020 0 1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8 MM c γ K − (GeV/c 2 )

Θ + ( Z + ) prediction of anti-decuplet Θ + (1530) D. Diakonov, V. Petrov, and M. Polyakov, Z. Phys. A 359 (1997) 305. • Exotic: S=+1 • Low mass: 1530 MeV • Narrow width: < 15 MeV • J p =1/2 + Jaffe & Wilzcek Jaffe & Wilzcek Diquark Diquark model predi odel predict also t also Anti-decoupl Anti-decouplet et pentaquark pentaquark J p =1/2+ (N(1440)) =1/2+ (N(1440)) M = [ 1890-180*Y] MeV

Confirmation from US and Russia CLAS/JLAB DIANA/ITEP γ d → p Κ + Κ − n K + Xe → Κ 0 p X 35 (Κ + n → Κ 0 p) 30 25 20 Events 15 10 5 0 1.5 1.6 1.7 1.8 1.9 Μ = 1539±2 MeV M(K + n) [ GeV/c 2 ] Γ < 9 MeV Μ = 1542±5 MeV Γ < 21 MeV hep-ex/0304040 hep-ex/0307018

Further confirmation with proton target 900 a b 22.5 32.58 / 27 40 counts counts P1 26.59 8.156 800 P2 1.537 0.3394E-02 20 35 Λ (1520) P3 0.1442E-01 0.4994E-02 700 P4 7.631 0.8350 Θ + (1540) 17.5 30 600 15 Μ = 1540±4±2 MeV Μ = 1537±10 MeV 25 N/20 MeV/c 2 500 12.5 Γ < 25 MeV Γ < 32 MeV 20 400 10 15 CLAS/Jlab 300 7.5 10 200 hep-ex/0307088 5 5 100 2.5 0 0 0 1.4 1.6 1.8 1.4 1.6 1.8 1.4 1.6 1.8 2 2.2 2.4 SAPHIR/ELSA mass(nK + )/GeV mass(n π + π - )/GeV M(nK + ), GeV/c 2 hep-ex/0307083 − − γ γ K K 0 * K π + π + 0 0 K K + + K K p p + + Z Z n n a) b)

Neut rino 24 scat t ering 22 Neon plus Deuterium 20 comb. / 10 MeV 18 16 14 12 Reanalysis of 10 8 bubble chamber 6 4 experiment s f rom 2 WA21, WA25, WA59, 0 1.4 1.6 1.8 2 2.2 2.4 2.6 0 m(K p) , GeV S E180, E632 18 Chi2 / ndf = 22.33 / 21 Chi2 / ndf = 22.33 / 21 ± ± mass = 1.533 mass = 1.533 0.004737 0.004737 16 ± ± sigma = 0.008379 sigma = 0.008379 0.002043 0.002043 ± ± excess = 25.56 excess = 25.56 6.417 6.417 14 ± ± comb. / 10 MeV p3 = 1.214 p3 = 1.214 0.5881 0.5881 A.Asrat yan,A.Dolgolenko, ± ± p4 = 17.71 p4 = 17.71 4.732 4.732 12 M.Kubant sev 10 hep-ex/ 0309042 8 6 Μ = 1533± 5 MeV 4 2 Γ < 20 MeV 0 1.5 1.6 1.7 1.8 1.9 0 m(K p) , GeV S M(K s p) spect rum ������ �� �� � ����� � ���� �� ��� � ������ �� ��� � ���� ��� ���� ��������� �� ����� � � � � ���� ������� ��� ���� ���� � ��� ����������� �� �������� !� �� ��� ���� � � � � � � ��� ������������ "��� ���� ������� ������� �� ��� "� �� ��� ������ ���� � �

COSY-ToF pp -> Σ + K o p

Summary of positive results Θ + Mass (MeV) Γ (MeV) Experiment : 1540 ± 10 ± 5 : 25 LEPS/SPring-8 : 1539 ± 2 ± few DIANA : 9 : 1542 ± 2 ± 5 CLAS(d) : 21 : 1540 ± 4 ± 2 SAPHIR : 25 ITEP( ν ) : 1533 ± 5 : 20 : 1555 ± 1 ± 10 : 26 ± 7 CLAS(p) : 19 ± 5 ± 2 : 1528 ± 2.6 ± 2.1 HERMES : 1526 ± 3 ± 3 ITEP(p) : 24 : 23 ZEUS : 1527+ 2 COSY : 1530+ 5 : 18

Increasing number of papers

First Manifestly Exotic Hadron in 40 Years • The discovery of the Θ +(1540) this year marks the beginning of a new and rich spectroscopy in QCD…. R.Jaffe Renaissance of Hadron Spectroscopy ! (Birth of Exotic Hadron Spectroscopy)

What is Θ + ? Theorest’s answer • Chiral Soliton ½+ • Quark model conventional ½ - correlated diquark ½+ • Hadronic bound state • Others Lattice QCD ½- Lattice QCD ½- ?

Questions about Θ + Spin-parity: J π = ½ + or ½ - or 3/2 -> selection of models s-wave or p-wave ? K+n -> K+n phase shift analysis pol .γ N -> K- Θ + decay distribution of Θ + angular dependence -> SPring-8 TPC project pp -> Σ+Θ+ (COSY) Hosaka

Questions about width • upper limit from direct measurement: 9 (20) MeV • – S.Nussinov (hep-ph/ 0307357) based on K + d scat t ering dat a Γ ( Θ +)< 6MeV – Arndt ,St rakovski & Workman (nucl-t h/ 0308012) based on exist ing K+N elast ic scat t ering dat a Γ ( Θ +) as small as 1 MeV KEK-SKS spectrometer K+p -> π+ Θ+ ( ∆ E~1.3 MeV)

High resolution spectroscopy of High resolution spectroscopy of pentaquark Θ + pentaquark (E559 at KEK-PS E559 at KEK-PS) • K.Imai, K.Miwa, M.Hayata, M.Miyabe, N.Muramatsu, M.Niiyama, N.Saito, M.Wagner, M.Yosoi (Kyoto U.) • T.Nagae, M.Ieiri, N.Noumi, Y.Sato, S.Sawada, M.Sekimoto, H.Takahashi, T.Takahashi, A.Toyoda (KEK) • H.Fujioka, T.Maruta (U. Tokyo) • T.Fukuda, P.K.Saha (Osaka ECU) • T.Nakano (RCNP) • K.Hicks (Ohio) • K+ p -> π + Θ + reaction with SKS spectrometer at KEK K6 beam line • excellent mass resolution ∆ E=1.0 MeV • Decay angular distribution for spin determination

Objective of the experiment Objective of the experiment • To confirm Θ+ with high statistics and in hadron reaction • -> 1500 events • To determine width (lifetime) of Θ+ • -> 1.3MeV resolution • To determine spin of Θ+ -> decay distribution ( Θ +->K+n)

SKS Spectrometer

Experimental setup around target Experimental setup around target and Range counter and Range counter

Yield estimation Yield estimation • ~1500 events/ 60shifts

p -> π + Θ + reaction reaction K + p ->

Total cross section for K+p-> π+Θ+ Total cross section for K+p-> Y. Y.Oh et al. Oh et al., he hep-ph/0311054 p-ph/0311054 Γ ( Θ +)~1MeV

Expected mass resolution of Θ + Expected mass resolution of

Background reactions for simulation

Experimental setup around target Experimental setup around target and Range counter and Range counter

Momentum resolution of range counter

Missing Mass Spectrum Missing Mass Spectrum (without K+ detection) (without K+ detection)

Missing Mass Spectrum Missing Mass Spectrum (with K+ detection) (with K+ detection)

Cross section to observe Θ+ as 5 σ peak vs width Without K+ detection With K+ detection

To establish anti-decuplet ฀ Ξ - - n K - -> K + Ξ - - , p K - -> K + π + Ξ - - ฀ Ξ + p K - -> K 0 π - Ξ + S=-2 S=0 Diakonov 2070 1710 MeV Jaffe, Wilczek 1750 1440 MeV If M( Ξ -- ) ~ 1750 MeV • (Jaffe & Wilczek, hep-ph/0307341) ->2GeV/c K- beam (BNL or KEK or (J-PARC)) !

S=-2 Penta-quark Ξ -- NA49 collaboration M=1862 MeV Γ <18 MeV hep-ex/0310014 5.6 σ

Charmed pentaquark HERA-H1 M=3099 MeV Γ =12 MeV M=3099 MeV =12 MeV

Pentaquarks at J-PARC • Precision study of Θ + (Θ + Factory) π -p -> K- Θ + , K + p -> π + Θ + , K + n->K + n 2 GeV/c π - 1GeV/c K+ 0.5 GeV/c K+ Ξ -- -- , Ξ + Κ -n -> K + Ξ -- K-p -> π -K o Ξ + 2.5 GeV/c K- 2.5 GeV/c K- be beam or high energy be am or high energy beam am • Charmed pentaquark ν +emulsion -> bound state ->K ππ p

Summary Summary • We need Θ+ “factory” to determine its spin- parity and structure. -> Intense K+ and π - beam ( K1.1&K1.8 ) • We have to establish other members Ξ --, Ξ + and others by K+(>2.5GeV/c) or high energy hadron beams • Charmed pentaquark! ν beam for hadron physics