Problem 248 - Odd strange particle cross sections (and also d, t, alpha)
Summary: Odd strange particle cross sections (and also d, t, alpha)
Status: CLOSED WORKSFORME
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic/cross_sections (show other problems)
Version: 3.0
Hardware: PC Linux
: P2 normal
Assignee: fwj
URL: http://helios.physics.utoronto.ca/~db...
Depends on:
Blocks:
 
Reported: 2001-04-14 13:32 CEST by dbailey
Modified: 2002-03-20 17:29 CET (History)
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Description dbailey 2001-04-14 13:32:56 CEST
I seem to be getting some odd results with high energy inelastic cross
sections of hadrons with basically the Example N04 physics list.  To track it
down,  I turn off all processes except "inelastic", and get the cross section
from the position distributions of the primary interaction verticess.  I have
looked at both hydrogen and tungsten.

    Protons, neutrons and pions seem reasonable, but strange particles and light
nuclei give odd results:

     (1) The K0L cross section is up to 30% larger than the K0S cross section.
The lowest energy I look at is 50 GeV, so I would expect both CP eignestates to
have essentially the same total hadronic cross section.

     (2) The strange particle cross sections increase dramatically at very high
energies relative to the non-strange cross sections. (See last 2 slides of
indicated URL.)

     (3) As expected, in both hydrogen and tungsten, the proton and neutron cross
sections are larger than the pion cross sections, and in hydrogen the lambda
cross section is larger than the kaon cross sections.  In tungsten, however, the
lambda cross section is always less than the kaon cross sections.

     (4) For light nuclei (i.e. d, t, alpha) the cross sections (above 1 GeV) in
tungsten seem roughly reasonable, but the primary particle loses no energy in the
interaction and no secondaries are produced even though this is supposed to be an
"inelastic" process.

      As always, I wonder if I am missing something.
Comment 1 fwj 2002-03-20 17:29:59 CET
I have tagged this as WORKSFORME.  The results observed were eventually
found to be "normal behaviour" in the sense that they showed what one would
expect from GHEISHA (in both G3 and G4), considering the range of the cross
section tables and the practical limitations in treatment of light nuclei.
On reviewing the e-mails, it appears that all the issues have been answered
by myself or Hans-Peter so I am closing this bug report.