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Title: A measurement of. Delta. sigma. sub L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states

Abstract

A measurement off {Delta}{sigma}{sub L}(np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. The results will help determine the isospin-zero (I = 0) scattering amplitudes, which are not well known above laboratory energies of 500 MeV, whereas the isospin-one (I = 1) amplitudes are fairly well-determined to 1 GeV. Data points were taken at the Los Alamos Meson Physics Facility (LAMPF) at Los Alamos, New Mexico, for five neutron beam energies: 484, 568, 634,720 and 788 MeV; they are the first in this energy range. Polarized neutrons were produced by charge-exchange of polarized protons on a liquid deuterium target (LD{sub 2}). Large-volume neutron counters detected the neutrons that passed through a polarized proton target. The counters subtended a range of solid angles large enough to allow extrapolation of the scattered neutrons to 0{degree}. Two modifications to the LAMPF accelerator system which were made for this work are described. They included a beam buncher,'' which modified the normal rf-time structure of the proton beam and allowed for the selection of peak-energy neutrons by time-of-flight means, and a computerized beam steering program, which reduced systematic effects due to beam motion at the LD{sub 2} target. Themore » experimental values of {Delta}{sigma}{sub L}(np) are found to be consistent with other np data, including preliminary data from SIN and Saclay, but not with some results from Argonne which used a polarized proton beam and a polarized deuteron target. The I = 0 component was extracted from {Delta}{sigma}{sub L}(np) using existing pp data (I = 1), with the unexpected result that {Delta}{sigma}{sub L}(I = 0) was found to be essentially identical in shape to {Delta}{sigma}{sub L}(I = 1). The significance of this is not yet understood.« less

Authors:
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
DOE/ER
OSTI Identifier:
6784251
Report Number(s):
LA-11905-T
ON: DE91000885; TRN: 90-033086
DOE Contract Number:  
W-7405-ENG-36; FG04-88ER40403
Resource Type:
Technical Report
Resource Relation:
Other Information: Thesis (Ph.D.). Thesis. Submitted to New Mexico State University, Las Cruces, NM
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; NUCLEON-NUCLEON INTERACTIONS; SCATTERING AMPLITUDES; TOTAL CROSS SECTIONS; BEAM BUNCHING; DATA ACQUISITION SYSTEMS; DATA ANALYSIS; DEUTERIUM TARGET; EXPERIMENTAL DATA; ISOSPIN; LINEAR ACCELERATORS; MEASURING METHODS; NEUTRON DETECTORS; NEUTRON REACTIONS; PARTIAL WAVES; POLARIZED BEAMS; PROTON REACTIONS; SPIN; ACCELERATORS; AMPLITUDES; ANGULAR MOMENTUM; BARYON REACTIONS; BARYON-BARYON INTERACTIONS; BEAM DYNAMICS; BEAMS; CHARGED-PARTICLE REACTIONS; CROSS SECTIONS; DATA; HADRON REACTIONS; HADRON-HADRON INTERACTIONS; INFORMATION; INTERACTIONS; MEASURING INSTRUMENTS; NUCLEAR REACTIONS; NUCLEON REACTIONS; NUMERICAL DATA; PARTICLE INTERACTIONS; PARTICLE PROPERTIES; RADIATION DETECTORS; TARGETS; 645103* - High Energy Physics- Particle Interactions & Properties-Experimental- Strong Interactions & Baryon & Meson Properties; 651000 - Nuclear Physics

Citation Formats

Beddo, M E. A measurement of. Delta. sigma. sub L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states. United States: N. p., 1990. Web. doi:10.2172/6784251.
Beddo, M E. A measurement of. Delta. sigma. sub L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states. United States. https://doi.org/10.2172/6784251
Beddo, M E. 1990. "A measurement of. Delta. sigma. sub L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states". United States. https://doi.org/10.2172/6784251. https://www.osti.gov/servlets/purl/6784251.
@article{osti_6784251,
title = {A measurement of. Delta. sigma. sub L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states},
author = {Beddo, M E},
abstractNote = {A measurement off {Delta}{sigma}{sub L}(np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. The results will help determine the isospin-zero (I = 0) scattering amplitudes, which are not well known above laboratory energies of 500 MeV, whereas the isospin-one (I = 1) amplitudes are fairly well-determined to 1 GeV. Data points were taken at the Los Alamos Meson Physics Facility (LAMPF) at Los Alamos, New Mexico, for five neutron beam energies: 484, 568, 634,720 and 788 MeV; they are the first in this energy range. Polarized neutrons were produced by charge-exchange of polarized protons on a liquid deuterium target (LD{sub 2}). Large-volume neutron counters detected the neutrons that passed through a polarized proton target. The counters subtended a range of solid angles large enough to allow extrapolation of the scattered neutrons to 0{degree}. Two modifications to the LAMPF accelerator system which were made for this work are described. They included a beam buncher,'' which modified the normal rf-time structure of the proton beam and allowed for the selection of peak-energy neutrons by time-of-flight means, and a computerized beam steering program, which reduced systematic effects due to beam motion at the LD{sub 2} target. The experimental values of {Delta}{sigma}{sub L}(np) are found to be consistent with other np data, including preliminary data from SIN and Saclay, but not with some results from Argonne which used a polarized proton beam and a polarized deuteron target. The I = 0 component was extracted from {Delta}{sigma}{sub L}(np) using existing pp data (I = 1), with the unexpected result that {Delta}{sigma}{sub L}(I = 0) was found to be essentially identical in shape to {Delta}{sigma}{sub L}(I = 1). The significance of this is not yet understood.},
doi = {10.2172/6784251},
url = {https://www.osti.gov/biblio/6784251}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Oct 01 00:00:00 EDT 1990},
month = {Mon Oct 01 00:00:00 EDT 1990}
}