Measurement of energy-level splitting from Charge-Symmetry Breaking in A = 4 mirror hypernuclei
Using the STAR experiment at RHIC, researchers measured the binding energies of A=4 mirror hypernuclei (⁴ΛH and ⁴ΛHe) in Au+Au collisions to precisely quantify charge-symmetry breaking in Λ–nucleon interactions, revealing that the energy-level splitting effects in ground and excited states are comparable in magnitude but opposite in sign.