Problem 1292 - Gross energy non-conservation in anti-proton annihilation of C, N and O
Summary: Gross energy non-conservation in anti-proton annihilation of C, N and O
Status: RESOLVED FIXED
Alias: None
Product: Geant4
Classification: Unclassified
Component: processes/hadronic/models/chiral_inv_phase_space (show other problems)
Version: 9.4
Hardware: PC Linux
: P5 major
Assignee: Alberto.Ribon
URL:
Depends on:
Blocks:
 
Reported: 2012-03-07 14:23 CET by John Apostolakis
Modified: 2012-10-10 12:54 CEST (History)
2 users (show)

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Description John Apostolakis 2012-03-07 14:23:47 CET 
ATLAS has found an event in which multiple very energetic tracks, which did not come from the proton-proton interaction, appear during a simulation.  

They tracked down the problem to the production of multiple particles with energy above 20 GeV from of an anti-proton annihilation at rest.

The list of secondaries from the first event included 
• 63 GeV deuteron
• 84 GeV proton
• 310 GeV neutron
• 734 GeV neutron

A message precedes this output, and appears to be correlated to this interaction:

• *G4QH::DecIn2:*Boost* 4M=(502.543,217.45,155.206;-3164.85),e-p=-3733.99
• *!*G4QE::FSI: 939.565+939.565=1879.13>-14554

An investigation has found that it occurs when the target nucleus is Carbon, Nitrogen or Oxygen at a rate of one every 5-10 million interactions.
Comment 1 John Apostolakis 2012-10-10 12:54:39 CEST 
A fix for this problem was created by Vladimir Ivantchenko.

It is included in 9.4-patch01.