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Cascade Baryon Spectroscopy with Kaon Beams. M. Naruki (Kyoto Univ ) 2016/5/17, Tallahassee , Baryon2016. Outline. Introduction Current Status of Cascades Experimental opportunities with kaon beams Future Plans Strange to Charm Summary. Ξ Baryon. σ (KN).
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Cascade Baryon Spectroscopywith Kaon Beams M. Naruki (Kyoto Univ) 2016/5/17, Tallahassee, Baryon2016
Outline • Introduction • Current Status of Cascades • Experimental opportunities with kaon beams • Future Plans • Strange to Charm • Summary
Ξ Baryon σ(KN) • Baryon with;S = -2, I = ½ 100μb ΔM~200MeV 10μb 1μb Ξ(1530) 3/2+ (****) Ξ(1321) 1/2+ (****)
First Discovery • Cascade decay Ξ− Cosmic ray w/cloud chamber Manchester group, 1952 Ξ0 1 GeV/c K− w/ bubble chamber Alvares et al., LRL, Berkeley, 1959
Observed States QM calc. by Chao, Isgur & Karl So far, 11 states were reported. • existence is certain : 2 • need confirmation : 4 • evidence is fair : 2 • evidence is poor : 3 Quark Model prediction • 44 states up to 2.3 GeV Exp.
Ξ* Production • Medium Energy Separated beam • 3~5 GeV/c K− p σ~10μb • bubble chamber experiment in 60-70’s • High Energy Separated beam • ~20, 345 GeV/c π−p inclusive σ~1μb • bubble chamber exp. at CERN • Hyperon Beam • 116GeV/c Ξ− Be at CERN-SPS Clean Kaon Beam is desirable
Studies of QQqsystem Qqq qqq QQq • strange quark is enough heavy • currently the only baryon to investigate QQq systems q-q q λ Q -Q Q ρ Ξ ρ Ω λ QM calc. by T. Yoshida, Hiyama, Hosaka, Oka, Sadato, PRD92(2015)114029
Experimental Data ΞQQ ρ ? ρ λ 5/2- 3/2- 1/2-
Advantages • narrow& separated resonances • Γ<30MeV • no overlap complications with other states • missing / invariant mass identification • “cascade decay” – special topology • good determination of interaction vertices • parity determination • self-analyzing • polarized target
K-p qualities • K−p K+X at 5GeV/c • Medium Energy Separated Beamline at AGS • two arms on both sides of MPS. • statistics is not so high, however higher excited states seem to be identified on the missing mass spectra of the K−pK+X reaction. 5GeV/c K−pK+X Jenkins at al., PRL51(‘83)951 Ξ(1820) g.s. Ξ(2250) Ξ(2025) Ξ(2370)
Ξ(1690)*** 4.2GeV/c K-pYKKπ Hyperon beam @ CERN Xi(1530)0 Xi(1690)0 Xi(1690)0 3μb 4.7σ Dionisi et al., PL,80B,(’78)145 Γ(Ξπ)/Γ(ΣK)<0.09 Adamovich et al., EPJ,C5(‘98)621 Ξπ / ΣK / ΛK
Ξ(1950)*** Ξ+Be • single state? 3.7σ K−p ΞBe Biagi et al., ZPC,34(‘87)15 (relative) amplitude of each resonances
Exotics • Ξ(1690) • too light compared with QM calculations. • K̅Σ molecular state T. Sekihara, PTEP (2015) 091D01 • Ξ−−(1860) • member of 10, S=-2,I=2/3,Q=-2 • only NA49 reported positive evidence in Ξ-π-/Ξ-π+ • combinatorial background is much suppressed in K-p reaction • w/1μb cross section, IK-=106ppp, 1% LD2 target, 40days, acceptance~10% ~3x103 counts
Ξ Spectroscopywith kaon beam • Missing & Invariant Mass Spectroscopy • 5 GeV/c K− p reaction up to 2.5 GeV Ξ * by K* tagging, threshold momentum for 2.5 GeV Ξ production is 5.5 GeV/c. Threshold momentum in p(K−,K+) (GeV/c) Ξ(2500) • Yield Estimation • IK=106/spill • σ=1μb • dΩ/4π = 50% • 4g/cm2 LH2 target • Y ~104/day Ξ(2030) Ξ(1950) Ξ(1820) current limit Ξ(1690) Ξ(1530) g.s.
First Ξ at J-PARC σ(K−pK+Ξ−) ~ 50μb 6x103Ξ/day at 39kW p(K−,K+) J-PARC E05 (preliminary)
J-PARCbird’s-eye view Tokai, Japan 400MeV LINAC 3GeV PS Neutrino Facility Materials &Life Science Facility 30GeV PS Hadron Experimental Facility slow extraction section
Ξhypernuclei in 12C(K-,K+) K0 → p0 nn L Physic Program at J-PARC d s u L,X u double-Λ d Particle Physics Hypernuclear Physics PentaquarkΘ+ SKS L6LHe K1.8 T-violation KL MC K1.8BR K1.1 CP Violation High momentum production target K1.1BR proton Hadron Mass Exotics Kaonic States φ(1020) kaonic nuclei lineshape of Λ(1405)
p K Timeline of Stage-2 Exp. 30 days now 3kW 10kW 25kW 50kW 270kW E05 E19 Ξ-Hypernucleus (priority 1) Search for PentaquarkΘ+ K1.8 E07 E03 E10 X rays from Ξ- Atom Double Strangeness with Emulsion neutron rich Λ-Hypernuclei E27 E13 Search for K-pp Gamma-ray spectroscopy of light hypernuclei (priority 2) E17 Kaonic 3He K1.8BR E15 deeply bound kaonic nucleus E31 spectral information of Λ(1405)
Power Upgrade Plan of 30GeV PS IK~6x105/spill Collimator & Shields • Titanium Ducts accident
High-momentum beam line branch angle : 5° primary line SM1 E16 spectrometer high-p line COMET junction COMET at SM1 high-p beam branches off from the primary line ・30 GeV primary proton (1010/s, 1012/s) ・8 GeV primary protonfor COMET ・secondary particles(~20 GeV/c) IK~105/spill
Spectrometer Design • Large acceptance (50% for K*) • high-resolution (ΔM~10MeV) • Possible decay mode measurement: Ξ→Ξπ/YKˉ • Multi-particle detection in the high rateenvironment Dipole magnet Pbeam= 4GeV/c scattered K 1~3GeV/c <40° p 1 ~ 2.5GeV/c <30° π0.3 ~ 0.8GeV/c 20~60° TOF wall p Beam Beam ID LH2-target DC sideway : π/K dE/dx forward : π/K/p TOF < 2.4GeV/c Fiber tracker Cherenkov
Physics Programs at High-p • Medium modification of mass of light vector mesons • dilepton measurement • Baryon Spectroscopy • Strangeness to Charm : Ξ Λc • close up diquark correlation inside baryon • Exotics • Ξ(1690) : K-Σ molecular states? • q(udss) • Ξ--? q q qq q Q
Charmed Baryon Spectroscopy Inclusivep(p-,D*-)Λc Using Missing Mass Techniques p(p-,D*-x) p(p) D0(Yc’) • Decay measurement in coincidence w/ p(π-,D*-) assists the missing mass spectroscopy. • Decay Branches: • diquarkcorrelation affects Γ(Λc*->pD)/Γ(Λc*->Σcπ). • Angular Distribution: spin, parity
Expected spectra: σGS = 1 nb N(Yc*)~1000events/1nb/100 days Sensitivity: ~0.1 nb (3σ, Γ~100 MeV) If there are Lc(2625) Lc* Lc(2880) Lc(2595) Lc* Lc(2940) Sc(2800) Lc(2765) Lc Lc* Sc(2520) Sc(2455)
Hadron Hall Extension HIHR HIHR:High resolution intense beam KL Precise Spectroscopy of Hypernuclei K1.1 K1.1: High-intensity & low-momentum K beam K10 Systematic Study for Hypernuclei(S=-1) KL: high intensity neutral kaons Measurement of CP violation K10: High-momentum separated secondary beam Ξ, Ω & Charm Spectroscopy • IK≃106/spill • Pmax < 10GeV/c
high momentum secondary beamline 2012 2017 2020? Beamline Pmax. K- Intensity Ξ(1620) Ξ(1690)
Summary • Experimental information of Cascades is largely lacking. • Cascades provide an unique opportunity to investigate QQq systems. • Some exotic states are expected. • The high-energy unseparated and mid-energy separated kaon beam enable us to study Cascade Baryons.
Ω Spectroscopy • Almost no information about Ω* • The production cross section of the ground state seems to be maximum at pK≈10GeV/c • σ(K−pΩ*XΞ*(1530)K−)~0.63μb at pK=11GeV/c • σ(K−pΩ*XΩππ)~0.29μb at pK=11GeV/c Aston et al., PRD 32 (’85) 2270 Separated Kaons up to ~10GeV/c are available at the K10 beam line.