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Manuscript Title: Computation of effective Regge trajectories for high energy two-body reactions.
Authors: D.J. Harrison, A.C. Irving, A.D. Martin
Catalogue identifier: ABCE_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 5(1973)153
Programming language: Fortran.
Computer: IBM 360/67.
RAM: 46K words
Word size: 32
Keywords: Elementary, High energy, Particle physics, Differential Cross-section, Empirical model, Normalisation, Effective Regge trajectory, Chew-frautschi plot, Least-squares.
Classification: 11.6.

Nature of problem:
Regge theory forms the basis of most of the current attempts to understand the strong interactions of elementary particles. Consequently as a preliminary to any serious analysis of high energy data for two-body reactions it is desirable to extract the effective Regge trajectory from the differential cross-section data for each reaction under study. A program has therefore been written to calculate these effective trajectories from the data. The program includes the option of determining the t-independent overall normalization of a given experiment, and it calculates the slope of the differential cross-section, and the integrated cross-section.

Solution method:
The effective Regge trajectory, alpha eff(t), for a given t is determined by first interpolating the experimental d sigma/dt to obtain values at the same t- but different s-values (where s is the square of of the c.m. energy and -t is the square of the 4-momentum transfer). The alpha eff is then calculated by performing a least-squares fit of ln(d sigma/dt)to ln s. Several t-values are fitted simultaneously so that the normalization of an experiment at a given s-value may be determined. Further, for a given energy, ln(d sigma/dt) can be parameterised by a polynomial in t of degree specified by the user, and a least-squares fit is used to calculate the parameters from the experimental data.

A maximum of six different reactions may be analysed in one run. For each reaction d sigma/dt data can be used at up to 20 different momenta, and alpha eff can be calculated at up to 20 different t-values.

Running time:
About eight s to calculate alpha eff at six t-values using d sigma/dt at eight different momenta.