High-precision spectroscopy of Λ hypernuclei with electron and meson beams

High-precision spectroscopy of Λ hypernuclei provides essential information on the Λ N interaction and on the structure of strange nuclear many-body systems. It is also closely related to current topics in few-body physics and nuclear astrophysics, including charge-symmetry breaking in Λ hypernuclei, the hypertriton puzzle, possible neutron-rich light hypernuclear systems, and the hyperon puzzle in neutron stars. In this article, I review ongoing and planned spectroscopic studies of Λ hypernuclei with complementary probes at JLab, MAMI, and J-PARC. Electron-induced reactions such as (e,e'K⁺) offer excellent absolute energy calibration and high-resolution spectroscopy for light-to-heavy hypernuclei. Decay-pion spectroscopy of electroproduced hypernuclei provides a powerful method for precise binding-energy studies of light systems, particularly the hypertriton. At J-PARC, the planned High-Intensity, High-Resolution beamline will enable high-intensity, high-resolution (π ⁺,K⁺) spectroscopy over a wide mass range and open a path toward a hypernuclear factory. The complementarity of these approaches will play a key role in establishing a comprehensive and precise picture of Λ hypernuclear structure from few-body systems to heavy hypernuclei.