Resonant formation of Λ(1405) by stopped-K- absorption in the deuteron

To solve the current debate on the position of the quasibound K(-)p state, namely, Lambda(1405) or Lambda*(1420), we propose to measure the T-21 = T-Sigma pi <-(K) over barN Sigma pi invariant-mass spectrum in stopped-K- absorption in the deuteron, since the spectrum, reflecting the soft and hard deuteron momentum distribution, is expected to have a narrow quasifree component with an upper edge of M = 1430 MeV/c(2), followed by a significant high-momentum tail toward the lower mass region, where a resonant formation of Lambda(1405) of any mass and width in a wide range will be clearly revealed. We introduce a deviation spectrum as defined by DEV = OBS (observed or calculated) / QF (nonresonant quasifree), in which the resonant component can be seen as an isolated peak free from the QF shape.