Electro-pion Production from Proton, Deuteron, and Helium-3
Electro-pion Production from Proton, Deuteron, and Helium-3

Author: Roger Jay Loucks

Publisher:

Published: 1996

Total Pages:

ISBN-13:

DOWNLOAD EBOOK

The cross section for the $p(e,espprimepisp+)n, d(e,espprimepisp+)2n$ and $sp3He(e,espprimepisp+)sp3H$ reactions are calculated using a simple model with pion, nucleon and $Delta$-resonance degrees of freedom for the kinematical conditions used in a recent Saclay experiment. For the $d(e,espprimepisp+)2n$ reaction, final state interactions between the two outgoing neutrons are found to have a large effect. The calculated quenching of the $pisp+$ production cross section for the deuterium target is in agreement with that observed experimentally. It is predicted that due to the strong final state interactions in the singlet S state of the two neutrons, the $d(e,espprimepisp+)2n$ cross section can have a large dependence on the orientation of the deuteron spin. For the $sp3He(e,espprimepisp+)sp3H$ reaction, the quenching is predicted to be $sim$0.4 which is in agreement with the unpublished results of the Mainz experiment. The four important contributions to the quenching are identified as: (i) the finite size i.e., the form factor of the trinucleons, (ii) the spin-isospin correlations in the trinucleons, (iii) the finite range of the propagation of the struck proton, and (iv) the possible pion-nucleon final state interactions.

Pion Production in the Neutron-proton Interaction
Pion Production in the Neutron-proton Interaction

Author: Taylan Akdoğan

Publisher:

Published: 2003

Total Pages: 298

ISBN-13:

DOWNLOAD EBOOK

Triply differential cross sections for the reactions np --> np[pi]0 and np --> pp[pi]− have been measured at the WNR Facility of the Los Alamos Neutron Science Center at the Los Alamos National Laboratory. The measurements were made with a pulsed neutron beam with a continuous spectrum ranging from as low as a few MeV up to about 800 MeV, which covers the pion threshold energy of about 280 MeV and above, on a cryogenic liquid Hydrogen target. The two outgoing nucleons are detected in coincidence. Pure CsI crystals were used on one side of the beam (12,̊ 200,̊ 280)̊, whose pulse height information was used for energy determination of identified protons, and on the opposite side of the beam (12-̊ 32)̊, the neutrons or protons were observed in an array of organic scintillators with time of flight information. Measurement of'both nucleon energies, by the combination of the pulsed nature of the beam, times of flight and pulse height, completely determines the kinematics and allows the angular distribution of the unobserved pions to be extracted for both np --> np[pi]0 and np --> pp[pi]− actions.