K+-nucleus elastic scattering and charge exchange

High-energy pion-nucleus elastic scattering

“…Results show qualitative agreement with previous work [6]. Modifications to the kaonnucleon amplitudes in the nuclear medium are needed to eliminate discrepancies between the theory and the data.…”

“…[6]. Our eikonal model, which is also a coordinate space approach and been shown to be a good approximation to the "model-exact" momentum space theory for high-energy pion scattering, can also be modified to treat the kaon scattering.…”

“…The data may also prove sensitive to modifications [6,7] of the properties of the nucleon in the nuclear medium, or reveal significant contributions from exchange currents [8].…”

Medium effects in K-nuclear interactions

“…These reaction and total cross sections provide 32 data points for the study of medium effects in K + nuclear interactions. It had been realized for the total cross sections data subset [12][13][14][15][16], and quite recently also for the reaction cross sections data subset [7,19], that the values of these integral cross sections, for the relatively dense C, Si and Ca nuclei, exceed substantially the predictions of the first-order optical potential V opt = tρ, by up to about 25%. This is inconceivable [13] for as weakly interacting hadron as the K meson is.…”

“…It is expected then [1] that K-nuclear interactions be well described, in terms of the free-space KN t matrix and the nuclear density ρ, by the first-order optical potential V opt = tρ. However, K + nucleus total cross section values [2][3][4][5][6][7] and reaction cross section values [7] derived from attenuation cross sections measured in transmission experiments, as well as elastic [8,9] and inelastic differential cross sections [8,10] and quasifree spectra [11], all point to a substantial departure of the order of 10-20% from the predictions of a simple tρ potential, even when many conventional nuclear medium effects are incorporated [12,13]. Several nonconventional medium effects have also been proposed to remedy the failure of the first-order optical potential approach, such as nucleon swelling [14], or density dependent vector meson masses [15], or polarizing the nuclear medium byNN excitations [16], or meson exchange currents [17,18], but as we shall discuss in the concluding section, none of these models provides a satisfactory solution to the discrepancy.…”