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

K.Imai: JPARC-WS 04/5/8 (KEK) K.Imai: JPARC-WS 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+

MMc

γK− (GeV/c2)

Events/(0.02 GeV/c2) 5 10 15 1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8

Μ = 1540±10 MeV Γ < 25 MeV Gaussian significance 4.6σ background

SPring-8 LEPS

• γ +n -> K- +K++n,

Θ+ -> K+ n Θ+: uudd s-bar

• T. Nakano et al.,

Phys.Rev.Lett. 91 (2003) 012002 hep-ex/0301020

Θ+(Z+) prediction of anti-decuplet

• Exotic: S=+1
• Low mass: 1530 MeV
• Narrow width: < 15 MeV
• Jp=1/2+

Θ+(1530)

M = [1890-180*Y] MeV

• D. Diakonov, V. Petrov, and M. Polyakov,
• Z. Phys. A 359 (1997) 305.

Jaffe & Jaffe & Wilzcek Wilzcek Diquark Diquark model predi

• del predict also

t also Anti-decoupl Anti-decouplet et pentaquark pentaquark Jp=1/2+ (N(1440)) =1/2+ (N(1440))

M(K+n) [GeV/c2] Events 5 10 15 20 25 30 35 1.5 1.6 1.7 1.8 1.9

Confirmation from US and Russia

DIANA/ITEP γ d → p Κ+ Κ− n K+ Xe → Κ0 p X (Κ+ n→ Κ0 p) CLAS/JLAB Μ = 1539±2 MeV Γ < 9 MeV Μ = 1542±5 MeV Γ < 21 MeV

hep-ex/0304040 hep-ex/0307018

+ +

a)

+

p Z b) K γ K K

− +

n K

+

K p π Z

+ −

γ K n K π

*

5 10 15 20 25 30 35 40 1.4 1.6 1.8 mass(nK+)/GeV

Θ+ (1540)

counts

a

100 200 300 400 500 600 700 800 900 1.4 1.6 1.8 mass(nπ+π-)/GeV

Λ (1520)

counts

b

2.5 5 7.5 10 12.5 15 17.5 20 22.5 1.4 1.6 1.8 2 2.2 2.4

32.58 / 27 P1 26.59 8.156 P2 1.537 0.3394E-02 P3 0.1442E-01 0.4994E-02 P4 7.631 0.8350

M(nK+), GeV/c2 N/20 MeV/c2

Further confirmation with proton target

Μ = 1540±4±2 MeV Γ < 25 MeV Μ = 1537±10 MeV Γ < 32 MeV SAPHIR/ELSA hep-ex/0307083 CLAS/Jlab hep-ex/0307088

Neut rino scat t ering

1.4 1.6 1.8 2 2.2 2.4 2.6 2 4 6 8 10 12 14 16 18 20 22 24

p) , GeV

S

m(K

Neon plus Deuterium

• comb. / 10 MeV

1.5 1.6 1.7 1.8 1.9 2 4 6 8 10 12 14 16 18 Chi2 / ndf = 22.33 / 21 0.004737 ± mass = 1.533 0.002043 ± sigma = 0.008379 6.417 ± excess = 25.56 0.5881 ± p3 = 1.214 4.732 ± p4 = 17.71

p) , GeV

S

m(K

• comb. / 10 MeV

Chi2 / ndf = 22.33 / 21 0.004737 ± mass = 1.533 0.002043 ± sigma = 0.008379 6.417 ± excess = 25.56 0.5881 ± p3 = 1.214 4.732 ± p4 = 17.71

• !
• "
• "
• A.Asrat yan,A.Dolgolenko,

M.Kubant sev

hep-ex/ 0309042 Reanalysis of bubble chamber experiment s f rom WA21, WA25, WA59, E180, E632

M(Ksp) spect rum

Μ = 1533± 5 MeV Γ < 20 MeV

COSY-ToF

pp -> Σ+Kop

Summary of positive results

Θ+ Mass (MeV) Γ (MeV)

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

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: Jπ= 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 K+p -> π+ Θ+ KEK-SKS spectrometer (∆E~1.3 MeV)

High resolution spectroscopy of High resolution spectroscopy of pentaquark pentaquark Θ+ (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

K+p -> p -> π+Θ+ reaction reaction

Total cross section for K+p-> Total cross section for K+p->π+Θ+

Y. Y.Oh et al. Oh et al., he hep-ph/0311054 p-ph/0311054

Γ(Θ+)~1MeV

Expected mass resolution of Expected mass resolution of Θ+

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 5σ 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- -> K0 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

5.6σ

Charmed pentaquark HERA-H1

M=3099 MeV M=3099 MeV Γ=12 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-KoΞ+ 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 ->Kππp

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