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Saha PK, Fukuda T, Imoto W, Ahn JK, Ajimura S, Aoki K, Bhang HC, Fujioka H, Hotchi H, Hwang JI, Itabashi T, Kang BH, Kim HD, Kim MJ, Kishimoto T, Krutenkova A, Maruta T, Miura Y, Miwa K, Nagae T, Noumi H, Outa H, Ohtaki T, Sakaguchi A, Sato Y, Sekimoto M, Shimizu Y, Tamura H, Tanida K, Toyoda A, Ukai M, Yim HJ. Production of the neutron-rich hypernucleus 10LambdaLi in the (pi-,K+) double charge-exchange reaction. Phys Rev Lett 2005; 94:052502. [PMID: 15783631 DOI: 10.1103/physrevlett.94.052502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2004] [Indexed: 05/24/2023]
Abstract
In order to produce a neutron-rich Lambda hypernucleus for the first time, we carried out an experiment by utilizing the (pi-,K+) double charge-exchange reaction on a 10B target. We observed the production of a 10LambdaLi hypernucleus. The cross section for the Lambda bound region was found to be 11.3+/-1.9 nb/sr with the 1.2 GeV/c incident momentum, which is compared with the 10LambdaB hypernucleus production cross section, 7.8+/-0.3 microb/sr, in the (pi+,K+) reaction with a 1.05 GeV/c incident momentum beam.
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Affiliation(s)
- P K Saha
- Osaka Electro-Communication University, Neyagawa, Osaka 572-8530, Japan
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Ukai M, Ajimura S, Akikawa H, Alburger DE, Banu A, Chrien RE, Franklin GB, Franz J, Hashimoto O, Hayakawa T, Hotchi H, Imai K, Kishimoto T, May M, Millener DJ, Minami S, Miura Y, Miyoshi T, Mizunuma K, Nagae T, Nakamura SN, Nakazawa K, Okayasu Y, Pile P, Quinn BP, Rusek A, Sato Y, Sutter R, Takahashi H, Tang L, Tamura H, Tanida K, Yuan L, Zhou SH. Hypernuclear fine structure in (16)(Lambda)O and the LambdaN tensor interaction. Phys Rev Lett 2004; 93:232501. [PMID: 15601150 DOI: 10.1103/physrevlett.93.232501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Indexed: 05/24/2023]
Abstract
We have observed two gamma-ray transitions in (16)(Lambda)O from the 6.6 MeV excited 1(-)(2) state to both ground-state spin-doublet members (1(-)(1),0(-)) by the (K-,pi(-)gamma) reaction. We have obtained the ground-state doublet spacing to be 26.4+/-1.6(stat)+/-0.5(syst) keV and the excitation energy of the 1(-)(2) state to be 6561.7+/-1.1(stat)+/-1.7(syst) keV. The ground-state doublet spacing provides a small but nonzero strength of the tensor interaction between a Lambda and a nucleon. This is the first experimental result on the LambdaN tensor interaction.
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Affiliation(s)
- M Ukai
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
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Noumi H, Saha PK, Abe D, Ajimura S, Aoki K, Bhang HC, Endo T, Fujii Y, Fukuda T, Guo HC, Imai K, Hashimoto O, Hotchi H, Kim EH, Kim JH, Kishimoto T, Krutenkova A, Maeda K, Nagae T, Nakamura M, Outa H, Sekimoto M, Saito T, Sakaguchi A, Sato Y, Sawafta R, Shimizu Y, Takahashi T, Tang L, Tamura H, Tanida K, Watanabe T, Xia HH, Zhou SH, Zhu LH, Zhu XF. Sigma-nucleus potential in A=28. Phys Rev Lett 2002; 89:072301. [PMID: 12190516 DOI: 10.1103/physrevlett.89.072301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2001] [Indexed: 05/23/2023]
Abstract
We have studied the (pi(-),K+) reaction on a silicon target to investigate the sigma-nucleus potential. The inclusive spectrum was measured at a beam momentum of 1.2 GeV/c with an energy resolution of 3.3 MeV (FWHM) by employing the superconducting kaon spectrometer system. The spectrum was compared with theoretical calculations within the framework of the distorted-wave impulse approximation, which demonstrates that a strongly repulsive sigma-nucleus potential with a nonzero size of the imaginary part reproduces the observed spectrum.
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Affiliation(s)
- H Noumi
- High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
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Hashimoto O, Ajimura S, Aoki K, Bhang H, Hasegawa T, Hotchi H, Kim YD, Kishimoto T, Maeda K, Noumi H, Ohta Y, Omata K, Outa H, Park H, Sato Y, Sekimoto M, Shibata T, Takahashi T, Youn M. Proton energy spectra in the nonmesonic weak decay of 12lambdaC and 28lambdaSi hypernuclei. Phys Rev Lett 2002; 88:042503. [PMID: 11801115 DOI: 10.1103/physrevlett.88.042503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2001] [Indexed: 05/23/2023]
Abstract
Numbers of protons per Gamma hypernuclear weak decay were measured as a function of proton energy above 40 MeV, explicitly identifying production of Gamma hypernuclei by the (pi+,K+) reaction. The ratios between the neutron-stimulated to proton-stimulated nonmesonic decay widths, Gamma((Lambda)n-->nn)/Gamma((Lambda)p-->np) ( = Gamma(n)/Gamma(p)) were extracted by fitting the proton energy spectra. The present result claims that the proton yields are suppressed and the Gamma(n)/Gamma(p) ratios are close to 1 both for 12LambdaC and 28LambdaSi in contradiction to theoretical expectations based on meson exchange models.
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Affiliation(s)
- O Hashimoto
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
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Ahn JK, Ajimura S, Akikawa H, Bassalleck B, Berdoz A, Carman D, Chrien RE, Davis CA, Eugenio P, Fischer H, Franklin GB, Franz J, Fukuda T, Gan L, Hotchi H, Ichikawa A, Imai K, Kahana SH, Khaustov P, Kishimoto T, Koran P, Kohri H, Kourepin A, Kubota K, Landry M, May M, Meyer C, Meziani Z, Minami S, Miyachi T, Nagae T, Nakano J, Outa H, Paschke K, Pile P, Prokhabatilov M, Quinn BP, Rasin V, Rusek A, Schmitt H, Schumacher RA, Sekimoto M, Shileev K, Shimizu Y, Sutter R, Tamagawa T, Tang L, Tanida K, Yamamoto K, Yuan L. Production of (4)(double Lambda)H hypernuclei. Phys Rev Lett 2001; 87:132504. [PMID: 11580581 DOI: 10.1103/physrevlett.87.132504] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2001] [Indexed: 05/23/2023]
Abstract
An experiment demonstrating the production of double-Lambda hypernuclei in (K(-),K(+)) reactions on (9)Be was carried out at the D6 line in the BNL alternating-gradient synchrotron. The technique was the observation of pions produced in sequential mesonic weak decay, each pion associated with one unit of strangeness change. The results indicate the production of a significant number of the double hypernucleus (4)(double Lambda)H and the twin hypernuclei (4)(Lambda)H and (3)(Lambda)H. The relevant decay chains are discussed and a simple model of the production mechanism is presented. An implication of this experiment is that the existence of an S = -2 dibaryon more than a few MeV below the double Lambda mass is unlikely.
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Affiliation(s)
- J K Ahn
- Department of Physics, Pusan National University, Pusan 609-735, Korea
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Tanida K, Tamura H, Abe D, Akikawa H, Araki K, Bhang H, Endo T, Fujii Y, Fukuda T, Hashimoto O, Imai K, Hotchi H, Kakiguchi Y, Kim JH, Kim YD, Miyoshi T, Murakami T, Nagae T, Noumi H, Outa H, Ozawa K, Saito T, Sasao J, Sato Y, Satoh S, Sawafta RI, Sekimoto M, Takahashi T, Tang L, Xia HH, Zhou SH, Zhu LH. Measurement of the B(e2) of (7)(lambda)Li and shrinkage of the hypernuclear size. Phys Rev Lett 2001; 86:1982-1985. [PMID: 11289835 DOI: 10.1103/physrevlett.86.1982] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2000] [Indexed: 05/23/2023]
Abstract
We report on the first measurement of a hypernuclear gamma-transition probability. gamma rays emitted in the E2(5/2(+)-->1/2(+)) transition of (7)(Lambda)Li were detected by a large-acceptance germanium detector array (Hyperball), and the lifetime of the parent state ( 5/2(+)) was determined by the Doppler shift attenuation method. The obtained result, 5.8(+0.9)(-0.7)+/-0.7 ps, was then converted into the reduced transition probability [ B(E2)] to be B(E2;5/2(+)-->1/2(+)) = 3.6+/-0.5(+0.5)(-0.4) e(2) fm(4). Compared with the B(E2) of the corresponding E2(3(+)-->1(+)) transition in the 6Li nucleus, our result gives evidence that the size of the 6Li core in (7)(Lambda)Li is smaller than the 6Li nucleus in the free space.
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Affiliation(s)
- K Tanida
- Department of Physics, University of Tokyo, Japan
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Tamura H, Tanida K, Abe D, Akikawa H, Araki K, Bhang H, Endo T, Fujii Y, Fukuda T, Hashimoto O, Imai K, Hotchi H, Kakiguchi Y, Kim JH, Kim YD, Miyoshi T, Murakami T, Nagae T, Noumi H, Outa H, Ozawa K, Saito T, Sasao J, Sato Y, Satoh S, Sawafta RI, Sekimoto M, Takahashi T, Tang L, Xia HH, Zhou SH, Zhu LH. Observation of a spin-flip M1 transition in 7(lambda)Li. Phys Rev Lett 2000; 84:5963-5966. [PMID: 10991099 DOI: 10.1103/physrevlett.84.5963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2000] [Indexed: 05/23/2023]
Abstract
Using a large-acceptance germanium detector array (Hyperball), we have observed a spin-flip M1 gamma transition between the ground-state spin doublet of (7)(Lambda)Li (3/2(+)-->1/2(+)). The observed energy of 691.7+/-0.6(stat)+/-1.0(syst) keV provides crucial information on the strength of the spin-spin interaction between a Lambda and a nucleon. This is the first observation of well-identified hypernuclear gamma transitions using germanium detectors.
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Affiliation(s)
- H Tamura
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
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