|Message: Differences in Quasi-Elastic scattering processes in G18.104.22.168p02 and G4.9.4p01||Not Logged In (login)|
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I am trying to simulate a 31 GeV/c proton colliding on a carbon target. I would like to investigate the quasi-elastic scattering, i.e. events where a proton scatters off one of the nucleons of the carbon nucleus (also known as incoherent elastic scattering).
From previous studies, one can find quasi-elastic events in the QGSP_BERT physics list according to the following cuts: - the process is referred to as an inelastic interaction - after the interaction, three particles are propagated: the proton, with a momentum greater than 29.8 GeV the nucleus and the nucleon
My problem is that after switching from geant4.9.3p02 to geant4.9.4p01, and using the same physics list and the same cuts in both cases, I don't have the same results. On a global point of view, cross sections for this process in the two versions of geant4 are compatible with each other, but if I look specificly to angular or transfer momentum (t) distributions, I can see up to a factor of two difference as you can see on the attached files.
One can observe the same behaviour with other physics list, such as QGSC_BERT, and hence applying a different set of cuts.
Since in the release notes, it is written that the Bertini cascade code has been re-written, would it be possible that our cuts might be obselete with the transition to the new Geant4?
Attachment: http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2011/05/17/09.21-84825-comp_g4_t.png http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2011/05/17/09.21-39994-comp_g4_qe_theta.png
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