The energy spacing between the spin-doublet bound state of He-4(Lambda)(1(+), 0(+)) was determined to be 1406 +/- 2 +/- 2 keV, by measuring gamma rays for the 1(+) -> 0(+) transition with a high efficiency germanium detector array in coincidence with the He-4(K-, pi(-))(Lambda)(4). He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus H-4(Lambda), the present result clearly indicates the existence of charge symmetry breaking (CSB) in Lambda N interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the 0(+) ground state but is vanishingly small in the 1(+) excited state, demonstrating that the Lambda N CSB interaction has spin dependence.

Observation of Spin-Dependent Charge Symmetry Breaking in Lambda N Interaction: Gamma-Ray Spectroscopy of He-4(Lambda) / Yamamoto, T; Agnello, Michelangelo; Akazawa, Y.; Amano, N; Aoki, K.; Botta, E.; Chiga, N.; Ekawa, H.; Evtoukhovitch, P.; Feliciello, A.; Fujita, M.; Gogami, T.; Hayakawa, S.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - STAMPA. - 115:22(2015), pp. 1-5. [10.1103/PhysRevLett.115.222501]

Observation of Spin-Dependent Charge Symmetry Breaking in Lambda N Interaction: Gamma-Ray Spectroscopy of He-4(Lambda)

AGNELLO, MICHELANGELO;
2015

Abstract

The energy spacing between the spin-doublet bound state of He-4(Lambda)(1(+), 0(+)) was determined to be 1406 +/- 2 +/- 2 keV, by measuring gamma rays for the 1(+) -> 0(+) transition with a high efficiency germanium detector array in coincidence with the He-4(K-, pi(-))(Lambda)(4). He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus H-4(Lambda), the present result clearly indicates the existence of charge symmetry breaking (CSB) in Lambda N interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the 0(+) ground state but is vanishingly small in the 1(+) excited state, demonstrating that the Lambda N CSB interaction has spin dependence.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2640243
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