(K −, K +) reaction on nuclear targets at PK = 1.65 G

Abstract

The forward-angle cross sections of the (K −, K +) reaction on nuclear targets of C, Al, Cu, Ag and Pb have been measured at the K − incident momentum of 1.65 GeV/ c in a side range K + momentum. The obtained K + momentum spectrum for each target nucleus is characterized by a peak in the high-momentum region ( p K + > 0.95 GeV/ c) and a broad bump in the low-momentum region ( p K + < 0.95 GeV/ c). A comparison of the measured spectrum with a DWIA calculation indicates that the quasifree process, K −(p) → K + Ξ −, is dominant in the high-momentum region. The target mass-number dependence of the cross section is well fitted with A α , where α is 0.38 ± 0.03 for the high-momentum region and 0.56 ± 0.02 for the low-momentum region. The result indicates that the quasifree process takes place at the peripheral of the target nucleus, whereas the two-step processes are dominant in the low-momentum region.