55 research outputs found
Photopion reactions on deltas preexisting in nuclei
Reactions A(\gamma, pi^+p) are considered to proceed through the formation of
pion-proton pairs on delta constituents in nuclei. We develop the
nonrelativistic operator for \Delta^{++}(\gamma, pi^+)p process in an arbitrary
frame. The calculated cross section for C12(\gamma, \pi^+p) reaction is
compared to the existing experimental data.Comment: 8 pages, 3 figure
Spin asymmetry for the 16O(gamma,pi- p) reaction in the Delta(1232) region within an effective Lagrangian approach
The spin asymmetry of the photon in the exclusive A(gamma,pi N)A-1 reaction
is computed employing a recently developed fully relativistic model based on
elementary pion production amplitudes that include a consistent treatment of
the spin-3/2 nucleon resonances. We compare the results of this model to the
only available data on Oxygen [Phys. Rev. C 61 (2000) 054609] and find that,
contrary to other models, the predicted spin asymmetry compares well to the
available experimental data in the Delta(1232) region. Our results indicate
that no major medium modifications in the Delta(1232) properties are needed in
order to describe the measured spin asymmetries.Comment: 16 pages, 7 figures. To be published in Physics Letters
Creation of the precision magnetic spectrometer SCAN-3
The new JINR project [1] is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article
- …