PROGRAM SUMMARY
Title of program:
PAPH
Catalogue identifier:
ADMO
Ref. in CPC:
131(2000)264
Distribution format: tar gzip file
Number of bits in a word:
32
Number of lines in distributed program, including test data, etc:
3157
Keywords:
Elementary particle physics, Empirical model, Partial-wave analysis,
p-3He, Strong interaction, chi-square-minimization, Error matrix.
Programming language used: Fortran
Nature of physical problem:
Partial-wave analysis (PWA) is a model independent method [1] to
determine the scattering amplitudes by means of fitting the experimental
data for many kinds of observables. PAPH can carry out the
energy-independent PWA of p-3He scattering [2]. The obtained phase
shifts can be used to construct the p-3He potential for studying the
n+p+3He system with various models of three body problem.
Method of solution
The available experimental data are stored in the input file for PAPH.
The chi-square-minimizing search is carried out [3] and the free
searched parameters are varied so as to reproduce the experimental data.
After completing the chi-square-minimizing search, the user obtains the
best-fit values of parameters (phase shifts, mixing parameters and
reflection parameters) together with their uncertainties simultaneously.
PAPH provides the solution of phase shifts, mixing parameters,
reflection parameters and also the determined helicity amplitudes. In
addition, the calculated values of the differential cross section and
various spin observables are provided. New experiments may be proposed
by studying the predicted values for spin observables by PAPH.
Restrictions on the complexity of the problem
Only the published observables can be analyzed by PAPH. If some new
observable is provided, a subroutine CROSE and the related subprograms
for inputting the data and outputting the observables (see Section 4)
should be modified to include them in the analysis.
References
[1] H.P. Stapp, T.J. Ypsilantis, N. Metropolis, Phys. Rev. 105 (1957)
33.
[2] Y. Yoshino, J. Nagata, H. Yoshino, M. Matsuda, Few Body Systems,
Proc 1st Asia Pacific Conference on Few Body Problems in Physics,
Noda/Kashiwa, Japan, 1999 (to be published).
[3] Y. Oyanagi, Library of Computer Center of University of Tokyo;
M.J.D. Powell, Computer Journal 7 (1965) 303.