Calculation of the 3He (in-flight K−,n) reaction for searching the deeply-bound K−pp state

The formation of a deeply-bound K−pp state by the 3He (in-flight K−,n) reaction is investigated theoretically in the distorted-wave impulse approximation using the Green's function method. The expected inclusive and semi-exclusive spectra at pK−=1.0GeV/c and θn=0° are calculated for the forthcoming J-PARC E15 experiment. We employ optical potentials between the K− and “pp” core-nucleus, and demonstrate systematically the dependence of the spectral shape on V0 and W0, which are the real and imaginary parts of the strength for the optical potential, respectively. The necessary condition to observe a distinct peak of the K−pp bound state with I=1/2, Jπ=0− in the spectrum turns out to be that the value of V0 is deeper than ∼−100MeV and W0 shallower than ∼−100 MeV, of which the strength parameters come up to recent theoretical predictions.