Cascade Baryon Spectroscopy with Kaon Beams M. Naruki (Kyoto Univ) 2016/5/17, Tallahassee, Baryon2016 1

Outline Introduction –Current Status of Cascades Experimental opportunities with kaon beams Future Plans –Strange to Charm Summary 2

Ξ Baryon Baryon with; S = -2, I = ½ 3 100μb 10μb 1μb1μb σ(KN) Ξ(1321) 1/2+ (****) Ξ(1530) 3/2+ (****) ΔM ~200MeV

First Discovery Cascade decay 4 Ξ − Cosmic ray w/cloud chamber Manchester group, 1952 Ξ 0 1 GeV/c K − w/ bubble chamber Alvares et al., LRL, Berkeley, 1959

Observed States 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 5 QM calc. by Chao, Isgur & Karl 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 6 Clean Kaon Beam is desirable

Studies of QQq system Qqq  qqq  QQq strange quark is enough heavy currently the only baryon to investigate QQq systems 7 QM calc. by T. Yoshida, Hiyama, Hosaka, Oka, Sadato, PRD92(2015) Ξ Ω q-q Q q Q - Q ρ λ ρ λ

Experimental Data 8 Ξ QQ 1/2- 3/2- 5/2- λ ρ ? ρ

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 9

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 − p  K + X reaction. 10 5GeV/c K − p  K + X Jenkins at al., PRL51(‘83)951 g.s. Ξ(1820) Ξ(2025) Ξ(2370) Ξ(2250)

Ξ （ 1690 ） *** 11 Xi(1530) 0 Xi(1690) 0 Hyperon CERN Adamovich et al., EPJ,C5(‘98) GeV/c K - p  YKKπ Dionisi et al., PL,80B,(’78)145 3μb3μb 4.7σ Ξπ / ΣK / ΛK Γ(Ξπ)/Γ(ΣK)<0.09

Ξ(1950)*** single state? 12 JpJp MassWidth 5/2- octet /2+ octet /2- decuplet have different decay pattern (Valderrama) Biagi et al., ZPC,34(‘87)15 Ξ+Be 3.7σ (relative) amplitude of each resonances ΞBe K−pK−p

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, I K- =10 6 ppp, 1% LD2 target, 40days, acceptance~10%  ~3x10 3 counts 13

current limit Ξ Spectroscopy with 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. 14 Yield Estimation I K =10 6 /spill σ=1μb dΩ/4π = 50% 4g/cm 2 LH2 target  Y ~10 4 /day g.s. Ξ (1530) Ξ (1690) Ξ (1820) Ξ (1950) Ξ (2030) Ξ (2500) (GeV/c) Threshold momentum in p(K−,K+)

First Ξ at J-PARC σ(K − p  K + Ξ − ) ~ 50μb 6x10 3 Ξ/day at 39kW J-PARC E05 (preliminary) p(K −,K + )

J-PARC bird’s-eye view 16 Tokai, Japan

d u u d s Pentaquark Θ +  Ξ hypernuclei in 12 C(K -,K + ) kaonic nuclei  6  He double-Λ Hypernuclear Physics Hadron Mass SKS K1.8BR KL K1.1BR High momentum K1.1 Physic Program at J-PARC φ(1020) K1.8 proton production target MC lineshape of Λ(1405) 17 Exotics K  →   L CP Violation T-violation Particle Physics Kaonic States

Timeline of Stage-2 Exp kW3kW50kW E19 E10 E13E27 E07 E03 E05   E17 E15 K1.8 K1.8BR Search for Pentaquark Θ + neutron rich Λ-Hypernuclei Search for K-pp Double Strangeness with Emulsion X rays from Ξ - Atom Ξ-Hypernucleus (priority 1) Gamma-ray spectroscopy of light hypernuclei (priority 2) Kaonic 3He deeply bound kaonic nucleus 30 days 25kW E31 spectral information of Λ(1405) 10kW now

Power Upgrade Plan of 30GeV PS accident Titanium Ducts Collimator & Shields 19 I K ~6x10 5 /spill

High-momentum beam line 20 SM1 at SM1 high-p beam branches off from the primary line ・ 30 GeV primary proton (10 10 /s, /s) ・ 8 GeV primary proton for COMET ・ secondary particles (~20 GeV/c) I K ~10 5 /spill E16 spectrometer COMET junction branch angle : 5° primary line high-p line

Spectrometer Design Large acceptance (50% for K*) high-resolution ( Δ M~10MeV) –Possible decay mode measurement: Ξ→Ξπ/YKˉ –Multi-particle detection in the high rate environment 21 P beam = 4GeV/c scattered K 1~3GeV/c <40° p 1 ~ 2.5GeV/c <30° π 0.3 ~ 0.8GeV/c 20~60° sideway : π/K dE/dx forward : π/K/p TOF < 2.4GeV/c sideway : π/K dE/dx forward : π/K/p TOF < 2.4GeV/c Beam p Dipole magnet Cherenkov TOF wall DC LH 2 -target Fiber tracker Beam ID

Physics Programs at High-p Medium modification of mass of light vector mesons –dilepton measurement Baryon Spectroscopy –Strangeness to Charm : Ξ  Λ c –close up diquark correlation inside baryon –Exotics Ξ(1690) : K-Σ molecular states? q(udss) Ξ--? 22 q q q Q qq

Charmed Baryon Spectroscopy 23 Using Missing Mass Techniques D0(Yc’)D0(Yc’) pp Inclusive p(  -,D* - ) Λ c p(  -,D* - x) * Decay measurement in coincidence w/ p(π -,D* - ) assists the missing mass spectroscopy. * Decay Branches: diquark correlation affects Γ(Λ c *->pD)/Γ(Λ c *->Σ c π). * Angular Distribution: spin, parity

Expected spectra: σGS = 1 nb 24 N(Yc*)~1000 events/1nb/100 days Sensitivity: ~0.1 nb (3σ, Γ~100 MeV) cc  c (2595)  c (2625)  c (2765)  c (2800)  c (2880)  c (2940)  c (2455)  c (2520)  c* c*c* c*c* If there are

Hadron Hall Extension 25 I K ≃ 10 6 /spill P max < 10GeV/c HIHR: High resolution intense beam Precise Spectroscopy of Hypernuclei K1.1: High-intensity & low-momentum K beam Systematic Study for Hypernuclei （ S=-1) K10: High-momentum separated secondary beam Ξ, Ω & Charm Spectroscopy KL: high intensity neutral kaons Measurement of CP violation

high momentum secondary beamline 26 Hadron Hall K1.8 2 GeV/c 1.4x10 6 High-momentum beamline High-p secondary 20 GeV/c 3.6x10 5 (unseparated) Extended Hall K10 10 GeV/c 1.9x ? 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. 27

Ω Spectroscopy Almost no information about Ω* The production cross section of the ground state seems to be maximum at p K ≈10GeV/c σ(K − p  Ω*X  Ξ*(1530)K−) ~0.63μb at p K =11GeV/c σ(K − p  Ω*X  Ωππ)~0.29μ b at p K =11GeV/c Aston et al., PRD 32 (’85) 2270 Separated Kaons up to ~10GeV/c are available at the K10 beam line.