高強度高分解能２次ビームラインを用いたハイパー核研究 味村周平（阪大ＲＣＮＰ） E10/E22 experiments The next experiments by High intensity High resolution beam line

Study on Neutron-Rich Hypernuclei J-PARC/E10 Aim to produce neutron-rich and exotic hypernuclei by the double charge-exchange (DCX) reaction NCX: (K-,p-), (p+,K+) reaction L-hypernuclei SCX: (K-,p0), (p-,K0) reaction DCX: (K-,p+), (p-,K+) reaction NCX ordinary nuclei SCX this study DCX N>>Z, exotic L-N interaction in n-rich env. glue-like role of L-hyperon 6LH 5H n p n p n n unbound nucleus L bound hypernucleus n n n n

Production by DCX reaction KEK-E521 experiment established 　　　　reaction Clean reaction g.s. K6 beam line @KEK-PS SKS spectrometer good energy resolution DBL = 2.5MeV (FWHM) BL=0 ds/dW~10nb/sr (1/1000 of NCX) ~45 events in bound region Increase yield 10 at J-PARC

beams, experimental equipments, beamtime request and prospects for E10 Pion beam High-Quality and High-Intensity negative pion beam Need STABLE slow beam extraction 1.5107 pion/spill (3 sec spill @30GeV) Experimental setup K1.8 beam line and SKS spectrometer Good resolution and large acceptance Beamtime Yield estimation Tiny (p-,K+) cross section (~10nb/sr) Not thick targets (3.5g/cm2) for resolution Need 3 weeks of beamtime per target Expect 300 n-rich hypernuclei in bound region Precise information on B.E. of n-rich hypernuclei resolution ~ 2.5MeV(FWHM) expected spectrum 6Li(p-,K+)6LH and 9Be(p-,K+)9LHe 6LH bound

J-PARC E22 Measurement of nonmesonic weak decay branch of 4LHe, G(Ln->nn) and G(Lp->np) Subjects: Properties of LN weak interaction spin/isospin structure parity information DI=1/2 rule in B-B int. (need meas. of both 4LH & 4LHe) } Determination of partial decay amplitudes n n p Λ p p n Λ p p n n Λ 0+ 0+ 0+ 0+ Ln→nn: 1S0, 3S1 1S0 1S0, 3S1 Lp→np: 1S0 1S0, 3S1 1S0, 3S1

Decay arm system n n p p CDC: veto p- from mesonic decay n/g TOF Large acceptance and high efficiency for NN Good PID capability (n/p/p/g) n n p p CDC: veto p- from mesonic decay n/g TOF p/p E/DE/range n/p charge-veto

beams, experimental equipments, beamtime request and prospects for E22 Pion beam High-Quality and High-Intensity negative pion beam Need STABLE slow beam extraction 1.5107 pion/spill (3 sec spill @30GeV) Experimental setup K1.8 beam line and SKS spectrometer Good resolution and large acceptance Beamtime Yield estimation cross section (~10mb/sr) Targets thickness (2g/cm2) Need 4 weeks of beamtime per target Expect 50,000 n-rich hypernuclei in bound region 1,300 Lpnp (BR~10%) and 75 Lnnn (if BR=1%) resolution ~ 2MeV(FWHM)

The next step: High Intensity High Resolution beam line intensity: 109 p/spill x 100 of K1.8 Dp/p ~ 10-4

With HIHR beamline Neutron-rich hypernuclei 6LH and 9LHe→systematic study of n-rich hypernuclei Short beamtime with high intensity (x100) 3 weeks → 1 day for the same statistics of E10 Precise information on the levels of n-rich hypernuclei Nonmesonic weak decay 4He(p-,K0)4LH @ Pp =1.8 GeV/c Ks spectrometer: reduce the acceptance by ~1/1000 (need optimize) Elementary cross section x0.2 BR(Ks→pp)=0.35 20msr each p+ p- Ks

backups

Beam Momentum bgct = 9.7 cm @ PK=1.53 GeV/c 1/5 At standard momentum for (p,K) reaction, 1050 MeV/c, bgct for kaon is 3.9cm. bgct = 9.7 cm @ PK=1.53 GeV/c