Coulomb effects and charge symmetry breaking for the A=4 hypernuclei

Phys. Rev. C 31, 1400 – Published 1 April 1985
A. R. Bodmer and Q. N. Usmani


The effect ΔBc of the Coulomb interaction on the Λ separation energy BΛ of HeΛ4 was obtained by variational calculations made for HeΛ4 and He3. These calculations were made for several values of q2 in the range 0≤q2≤9 where qe is the proton charge, i.e., the Coulomb repulsion was artificially boosted. For q2≲3, the dependence on q2 is linear, and interpolation to q2=1 gives the physical values with improved accuracy: -ΔBc=0.05±0.02 and 0.025±0.015 MeV for the ground and excited state, respectively. This procedure also gives more accurate values for the differences between the proton and neutron radii of He3. The corresponding differences of BΛ between HeΛ4 and HΛ4, to be attributed to charge symmetry breaking effects, are then 0.40±0.06 and 0.27±0.06 MeV. From these values we obtain a phenomenological charge symmetry breaking potential which is effectively spin independent. An examination of meson-exchange charge symmetry breaking models shows that these are consistent with the phenomenological charge symmetry breaking potential for the triplet but not for the singlet case.


  • Received 27 August 1984
  • Published in the issue dated April 1985

© 1985 The American Physical Society

Authors & Affiliations

A. R. Bodmer

  • Argonne National Laboratory, Argonne, Illinois 60439 and Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60637

Q. N. Usmani

  • Department of Physics, Aligarh Muslim University, Aligarh 202001, India

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