MOMDIS: a Glauber model computer code for knockout reactions

A computer program is described to calculate momentum distributions in stripping and diffraction dissociation reactions. A Glauber model is used with the scattering wavefunctions calculated in the eikonal approximation. The program is appropriate for knockout reactions at intermediate energy collisions (30 MeV⩽Elab/nucleon⩽2000 MeV30 MeV⩽Elab/nucleon⩽2000 MeV). It is particularly useful for reactions involving unstable nuclear beams, or exotic nuclei (e.g., neutron-rich nuclei), and studies of single-particle occupancy probabilities (spectroscopic factors) and other related physical observables. Such studies are an essential part of the scientific program of radioactive beam facilities, as in for instance the proposed RIA (Rare Isotope Accelerator) facility in the US.Program summaryTitle of program: MOMDIS (MOMentum DIStributions)Catalogue identifier:ADXZ_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXZ_v1_0Computers: The code has been created on an IBM-PC, but also runs on UNIX or LINUX machinesOperating systems: WINDOWS or UNIXProgram language used: Fortran-77Memory required to execute with typical data: 16 Mbytes of RAM memory and 2 MB of hard disk spaceNo. of lines in distributed program, including test data, etc.: 6255No. of bytes in distributed program, including test data, etc.: 63 568Distribution format: tar.gzNature of physical problem: The program calculates bound wavefunctions, eikonal S-matrices, total cross-sections and momentum distributions of interest in nuclear knockout reactions at intermediate energies.Method of solution: Solves the radial Schrödinger equation for bound states. A Numerov integration is used outwardly and inwardly and a matching at the nuclear surface is done to obtain the energy and the bound state wavefunction with good accuracy. The S-matrices are obtained using eikonal wavefunctions and the “t-ρρ” method to obtain the eikonal phase-shifts. The momentum distributions are obtained by means of a Gaussian expansion of integrands. Main integrals are performed with the Simpson's method.Typical running time: Almost all CPU time is consumed by calculations of integrals, specially for transverse momentum distributions which involves multiple integral loops. It takes up to 30 min on a 2 GHz Intel P4-processor machine.