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Title: Determination of low-energy parameters of neutron-proton scattering on the basis of modern experimental data from partial-wave analyses

Abstract

The triplet and singlet low-energy parameters in the effective-range expansion for neutron-proton scattering are determined by using the latest experimental data on respective phase shifts from the SAID nucleon-nucleon database. The results differ markedly from the analogous parameters obtained on the basis of the phase shifts of the Nijmegen group and contradict the parameter values that are presently used as experimental ones. The values found with the aid of the phase shifts from the SAID nucleon-nucleon database for the total cross section for the scattering of zero-energy neutrons by protons, {sigma}{sub 0} = 20.426 b, and the neutron-proton coherent scattering length, f = -3.755 fm, agree perfectly with experimental cross-section values obtained by Houk, {sigma}{sub 0} = 20.436 {+-} 0.023 b, and experimental scattering-length values obtained by Houk and Wilson, f = -3.756 {+-} 0.009 fm, but they contradict cross-section values of {sigma}{sub 0} = 20.491 {+-} 0.014 b according to Dilg and coherent-scattering-length values of f = -3.7409 {+-} 0.0011 fm according to Koester and Nistler.

Authors:
;  [1]
  1. National Academy of Sciences of Ukraine, Bogolyubov Institute for Theoretical Physics (Ukraine)
Publication Date:
OSTI Identifier:
21075900
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Atomic Nuclei; Journal Volume: 70; Journal Issue: 4; Other Information: DOI: 10.1134/S1063778807040072; Copyright (c) 2007 Nauka/Interperiodica; Article Copyright (c) 2007 Pleiades Publishing, Ltd; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; COHERENT SCATTERING; NEUTRONS; PARTIAL WAVES; PHASE SHIFT; PROTON-NEUTRON INTERACTIONS; PROTONS; SCATTERING LENGTHS; TOTAL CROSS SECTIONS; TRIPLETS

Citation Formats

Babenko, V. A., E-mail: pet@online.com.ua, and Petrov, N. M. Determination of low-energy parameters of neutron-proton scattering on the basis of modern experimental data from partial-wave analyses. United States: N. p., 2007. Web. doi:10.1134/S1063778807040072.
Babenko, V. A., E-mail: pet@online.com.ua, & Petrov, N. M. Determination of low-energy parameters of neutron-proton scattering on the basis of modern experimental data from partial-wave analyses. United States. doi:10.1134/S1063778807040072.
Babenko, V. A., E-mail: pet@online.com.ua, and Petrov, N. M. Sun . "Determination of low-energy parameters of neutron-proton scattering on the basis of modern experimental data from partial-wave analyses". United States. doi:10.1134/S1063778807040072.
@article{osti_21075900,
title = {Determination of low-energy parameters of neutron-proton scattering on the basis of modern experimental data from partial-wave analyses},
author = {Babenko, V. A., E-mail: pet@online.com.ua and Petrov, N. M.},
abstractNote = {The triplet and singlet low-energy parameters in the effective-range expansion for neutron-proton scattering are determined by using the latest experimental data on respective phase shifts from the SAID nucleon-nucleon database. The results differ markedly from the analogous parameters obtained on the basis of the phase shifts of the Nijmegen group and contradict the parameter values that are presently used as experimental ones. The values found with the aid of the phase shifts from the SAID nucleon-nucleon database for the total cross section for the scattering of zero-energy neutrons by protons, {sigma}{sub 0} = 20.426 b, and the neutron-proton coherent scattering length, f = -3.755 fm, agree perfectly with experimental cross-section values obtained by Houk, {sigma}{sub 0} = 20.436 {+-} 0.023 b, and experimental scattering-length values obtained by Houk and Wilson, f = -3.756 {+-} 0.009 fm, but they contradict cross-section values of {sigma}{sub 0} = 20.491 {+-} 0.014 b according to Dilg and coherent-scattering-length values of f = -3.7409 {+-} 0.0011 fm according to Koester and Nistler.},
doi = {10.1134/S1063778807040072},
journal = {Physics of Atomic Nuclei},
number = 4,
volume = 70,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • On the basis of the total cross sections for neutron-proton scattering in the region of laboratory energies below 150 keV, the value of {sigma}{sub 0} = 20.4288(146) b was obtained for the total cross sections for neutron-proton scattering at zero energy. This value is in very good agreement with the experimental cross sections obtained by Houke and Hurst, but it is at odds with Dilg's experimental cross section. By using the value that we found for {sigma}{sub 0} and the experimental values of the neutron-proton coherent scattering length f, the deuteron binding energy {epsilon}{sub t}, the deuteron effective radius {rho}{submore » t}(-{epsilon}{sub t}, -{epsilon}{sub t}), and the total cross section in the region of energies below 5 MeV, the following values were found in the shape-parameter approximation for the low-energy parameters of neutron-proton scattering in the spin-triplet and spin-singlet states: a{sub t} = 5.4114(27) fm, r{sub 0t} = 1.7606(35) fm, v{sub 2t} = 0.157 fm{sup 3}, a{sub s} = -23.7154(80) fm, r{sub 0s} = 2.706(67) fm, and v{sub 2s} = 0.491 fm{sup 3}.« less
  • In 1993 the Nijmegen group published the results of energy-dependent partial-wave analyses (PWAs) of the nucleon-nucleon (NN) scattering data for laboratory kinetic energies below Tlab = 350 MeV (PWA93). In this talk some general aspects, but also the newest developments on the Nijmegen NN PWAs are reported. We have almost finished a new energy-dependent PWA and will discuss some typical aspects of this new PWA; where it differs from PWA93, but also what future developments might be, or should be.
  • A study of the factors which govern a precise determination of the S- and P-wave pion-nucleon scattering lengths using phenomenological energy-dependent partial-wave analyses is made. The nuclear scattering lengths obtained result from rapidly convergent effective-range expansions and are shown to be insensitive to the energy cutoff. These phenomenological values are in general agreement with theoretical treatments.
  • The correlation between the root-mean-square matter radius of the deuteron, r{sub m}, and its effective radius, {rho}, is investigated. A parabolic relationship between these two quantities makes it possible to determine the root-mean-square radius r{sub m} to within 0.01% if the effective radius {rho} is known. The matter (r{sub m}), structural (r{sub d}), and charge (r{sub ch}) radii of the deuteron are found with the aid of modern experimental results for phase shifts from the SAID nucleon-nucleon database, and their values are fully consistent with their counterparts deduced by using the experimental value of the effective deuteron radius due tomore » Borbely and his coauthors. The charge-radius value of 2.124(6) fm, which was obtained with the aid of the SAID nucleon-nucleon database, and the charge-radius value of 2.126(12) fm, which was obtained with the aid of the experimental value of the effective radius {rho}, are in very good agreement with the present-day chargeradius value of 2.128(11) fm, which was deduced by Sick and Trautmann by processing world-average experimental data on elastic electron scattering by deuterons with allowance for Coulomb distortions.« less
  • The partial-wave inelasticity parameters of the amplitude for elastic pion-nucleon scattering are determined with the aid of the phenomenological amplitude for inelastic {pi}N {yields} {pi}{pi}N processes in the energy range extending to the threshold for the production of two pions. The resulting inelasticity parameters are compared with their counterparts derived from modern partial-wave analyses. The largest inelastic-scattering cross section in the P11 wave is in excellent agreement with the analogous value from the analysis performed at the George Washington University in 2006. For other waves, however, the present results differ in the majority of cases from respective values given bymore » partial-wave analyses (the distinctions are especially large for the isospin-3/2 amplitudes).« less