Re: Effects of PEATHREShold

From: Alfredo Ferrari <>
Date: Mon, 15 Jun 2009 08:11:11 +0200

Hi Joseph

the PEANUT model is anyway superior also at the high energies and it will
be the default since the next version.

Some jumps around 5 GeV (incident energy) is possible and it is not due to
the model but rather to the treatment and split of quasielastic
cross sections

| Alfredo Ferrari || Tel.: + |
| CERN-EN/STI || Fax.: + |
| 1211 Geneva 23 || e-mail: |
| Switzerland || |

On Sun, 14 Jun 2009, Joseph Comfort wrote:

> I am studying particle production for 30-GeV protons on a nickel target
> stack. I have usually prefered to use the PEATHREShold option of the
> PHYSICS card. I am now looking at things a bit more carefully.
> The attached plot shows some comparisons for the neutron energy
> distribution with the default 5-GeV limit and with a 50-GeV limit. In
> the upper part, there is a change in slope at about 5 GeV. Is this
> realistic? Or is the transition from the default PEANUT model to an
> extended version not properly smoothed out?
> The default version has a jump near 500 MeV, while the extended version
> is smoother (and is one of the reasons I prefer the extended version).
> The extended version also seems smoother overall in the lower figure,
> which goes up to 100 MeV.
> Another issue is a dependence on the upper limit. 50 GeV is well above
> any energies in the problem, but I get different results if I change it to
> 1000 GeV. It appears the random number sequence gets changed very early
> on because the numbers of produced particles are very similar. Why should
> that be? Is it affected somehow by the scaling of the model parameters?
> Finally, I am concerned with changes in the number of particles. With the
> extended limit, the number of protons and neutrons increase by about 10%
> (mosty at low energies). That is not unreasonable. However, the number
> of photons decreases by 1-2% and, more disturbingly, the number of Klongs
> decrease by about 20%! Where did they go?
> Thank you,
> Joe
Received on Mon Jun 15 2009 - 09:27:19 CEST

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