Deeply bound K(-)pp state in the He-3(in-flight K-,n) spectrum, and its moving pole near the pi Sigma N threshold

作者：Koike Takahisa^*; Harada Toru

来源：Physical Review C, 2009, 80(5): 055208.

DOI：10.1103/PhysRevC.80.055208

The formation of a deeply bound K(-)pp state with I=1/2, J(pi)=0(-), by the He-3(in-flight K-,n) reaction is theoretically investigated in a distorted-wave impulse approximation using the Green's function method. The expected inclusive and semiexclusive spectra at p(K)(-)=1.0 GeV/c and theta(lab)=0(degrees) are calculated for the forthcoming J-PARC E15 experiment. We demonstrate these spectra with several phenomenological K--"pp" optical potentials U-opt(E) that have an energy-dependent imaginary part multiplied by a phase space suppression factor, fitting to recent theoretical predictions or experimental candidates of the K(-)pp bound state. The results show that a cusplike peak at the pi Sigma N threshold is a unique signal for the K(-)pp bound state in the spectrum including the [K(-)pp]-> Y+N decay process from two-nucleon K- absorption, as well as a distinct peak of the K(-)pp bound state. The shape of the spectrum is explained by the trajectory of a moving pole of the K(-)pp bound state in the complex energy plane. The importance of the [K(-)pp]-> Y+N spectrum to extract clear evidence of the K(-)pp bound state is emphasized.

• 出版日期2009-11