Oct. 13th 2006

-ray spectroscopy study of

and

C12B11

Yue Ma Department of Physics

Tohoku University

Oct. 13th 2006 Hyp06

Collaboration 　 List 　 for KEK-PS E566

• Tohoku Univ.: T. Koike, S. Kinoshita, Y. Ma, Y. Miura, Y. Miyagi, K. Shirotori, T. Suzuki, H. Tamura, K. Tsukada, M. Ukai, K. Futatsukawa, K. Hosomi, M. Kawai, M. Mimori, N. Terada, N. Maruyama

• KEK: K. Aoki, H. Fujioka, Y. Kakiguchi, T. Nagae, D. Nakajima, H. Noumi, T. Takahashi, T.N. Takahashi, A. Toyota

• China Institute of Atomic Energy: Y.Y. Fu, S.H. Zhou• Kyoto Univ.: M. Dairaku, K. Miwa • Osaka E.C. Univ. : T. Fukuda, S. Minami, W. Imoto • Osaka Univ.: S. Ajimura • RIKEN: K. Tanida

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Background interaction (interaction parameters) Physics interests of the present experiment

Experimental setup & analysis Magnetic spectrometer & Missing mass analysis Hyperball2 apparatus & gamma-ray spectrum analysis

Preliminary results & discussionSummary

Outline of the presentation

N

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S

Central force VSpin-spin force

Tensor force T N spin-dependent spin-orbit forceNS

spin-dependent spin-orbit forceS

Background: ΛN interaction

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Physics interests of the present experiment

C12

can be employed to cross check the parameters.can help to solve the puzzle.B10

Itonaga & Millener's calculation

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( , ) /

Experimental setup: overview

Totally 12102

K C12 B11

C12

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Experimental setup & analysis: track reconstruction

Momentum of pion

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BGO suppression Ge efficiency

Experimental setup & analysis : Ge detectors

Photoelectric peak efficiency ~5 % @ 1.33 MeV when beam off Energy resolution = 5.3 keV (FWHM) @ 1.33 MeV when beam on Time resolution = 18 ns (FWHM) @ 1.33 MeV when beam on

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Preliminary results: states selection

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Preliminary results: gamma rays from ΛB11

keV2.06.261)2/52/7( :B11 E keV7.07.1481)2/52/1( :B11

E

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Preliminary results: gamma rays from ΛC

keV8.23.2667)21( :C 1212 E

12

2377

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Discussion

keV2.06.261)2/52/7( :B11 E

keV8.23.2667)21( :C 1212 E

keV7.07.1481)2/52/1( :B11 E 1020 keV

418 keV

2443 keVSN

SN

Δ

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Summary

KEK-E566: C (pi+, K+) / @ K6 beam line, KEKThree hypernuclear gamma-ray peaks were observed.

Two interaction parameters were derived from proper transitions.

SN : -0.7~-0.9 MeV

Δ : 0.3 MeV

Summary

keV2.06.261)2/52/7( :B11 E

keV7.07.1481)2/52/1( :B11 E

keV8.23.2667)21( :C 1212 E

SN : ~-0.4 MeV

Δ: ~0.43 MeV

ΛC12 12

ΛB11

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Present problems & future task

Production rate of the ground state hypernucleus is rather different from previous data.Other experiments show that the production rate of the gro

und state is about 7 counts/(g/cm )(10 pion) In our current analysis this value is

~ 2.3 counts/(g/cm )(10 pion) 2 9

2 9

C12

C12

9

9

2

2

Oct. 13th 2006 Hyp06

Candidate for ground state doublet transition of Gamma-ray energy is around 150 keV Number of counts is consistent with rough estimated value

Present problems & future task

Oct. 13th 2006 Hyp06

Clover Ge add back

Ge calibration

Photo-peak efficiency increased by 1.5 times

Experimental setup & analysis : Ge detectors

Oct. 13th 2006 Hyp06

Oct. 13th 2006 Hyp06

Background: Physics interests of the present experiment

• To measure the g-factor of a hyperon inside nuclear medium.

Doppler Shift Attenuation Method(DSAM)

Oct. 13th 2006 Hyp06

K

N1

N1

N2

N2N

N

N

N

N

NN

N

N

N

Background: ΛN interaction