n−pElastic Charge Exchange in the BeV Energy Region

Abstract

DECEMBER 15, 1962 (1962)] or in the K ~K system [S. Minami, Progr. Theoret. Phys. (Kyoto) 27, 215(1962)]. 5 If the Z particle is regarded as a bound state in the N -N system, it would then correspond to the 3 3 P 0 state.For an explanation of the notation, see the first paper cited in reference 4. 6 Another possible reaction mechanism is one in which the incident K~ meson interacts directly with the nucleon and a K meson is produced through a Yukawa-type interaction without any KK interaction.The n-p elastic charge-exchange cross section is expected, on the basis of isotopic -spin considerations, to decrease with increasing nucleon energy because the total cross sections for n-p and/)-/? approach equality with increasing energy. The highest energy charge-exchange measurements were reported by Larsen 1 at 710 MeV. He found the differential center-of-mass cross section at zero degrees to equal 6.3 mb/sr. In the BeV energy region the search for nucleon charge-exchange events has usually been ancillary to some other measurement. 2 This has resulted in little positive information, except for the conclusion that the charge-exchange cross section is small. We have measured this process at 2.04 and 2.85 BeV using the Cosmotron at Brookhaven.The experimental arrangement of the apparatus is shown in Fig.

Neutron-proton charge-exchange scattering from 8 to 29 GeV/c

“…Preliminary reports [1][2][3] of this work have been published elsewhere. Previous experiments [4][5][6][7][8][9][10][11][12] indicated that this process has several interesting characteristics. There is a peak in the angular distributions which is much sharper than the peak in p-p scattering.…”

“…The general shape of the cross section at 3 GeV/c [4,5] can be described by da/dt = A e -Bltl + C e -DIrl ,…”

“…(b) To study the energy dependence of the absolute cross sections by taking measurements over a wide energy range at one time. Previous measurements [4][5][6][7][8] indicated that the cross sections decreased with increasing incident neutron momentum as p~ab 2 to P~ab 3. This experiment, with data taken over a wide energy range with consistent normalization, would give accurate information on the energy dependence of the absolute cross sections.…”

One-Pion Contribution to Neutron-Proton Charge-Exchange Scattering

“…9 Byers 10 also calculated the high-energy n-p backward cross section using the coherent-droplet model with an OPE term dominating for large impact parameter.…”

Regge-Pole Models for Pion Exchange Reactions

“…5 These features of the cross section suggest that the long-range part of the interaction, hence, the small-angle cross section, is associated with the exchange of a single pion. The 5-channel helicity amplitudes M(\p', ^n> ^n>^p) f°r t nis process are given in Born approximation for single pion exchange by …”