RCNP

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• ????(??RCNP)
• E10/E22 experiments
• The next experiments by High intensity High
  resolution beam line

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Study on Neutron-Rich HypernucleiJ-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
NgtgtZ, exotic
L-N interaction in n-rich env.
glue-like role of L-hyperon
6LH
p
n
5H
n
p
n
n
L
unbound nucleus
bound hypernucleus
n
n
n
n
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Production by DCX reaction

• KEK-E521 experiment established
• reaction
• Clean reaction

g.s.
BL0
Increase yield ?10 at J-PARC
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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 _at_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
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J-PARC E22
Measurement of nonmesonic weak decay branch of
4LHe, G(Ln-gtnn) and G(Lp-gtnp)

• Subjects Properties of LN weak interaction
• spin/isospin structure
• parity information
• DI1/2 rule in B-B int. (need meas. of both 4LH
  4LHe)

Determination of partial decay amplitudes
p p n ?
p p n n ?
n n p ?
0
0
0
0
Ln?nn 1S0, 3S1 1S0 1S0, 3S1 Lp?np 1S0 1S0,
3S1 1S0, 3S1
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Decay arm system

• 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
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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 _at_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 (BR10) and 75 Ln?nn (if BR1)

resolution 2MeV(FWHM)
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The next step High Intensity High Resolution
beam line

• intensity 109 p/spill
• x 100 of K1.8
• Dp/p 10-4

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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 _at_ 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
10
backups
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Beam Momentum
1/5
At standard momentum for (p,K) reaction, 1050
MeV/c, bgct for kaon is 3.9cm.
bgct 9.7 cm _at_ PK1.53 GeV/c