Comment 2 for bug 1818393

Which process (initial state particles) and which energies you are
talking about?

Regards,

Alexander

On 03/03/2019 10:12, Sam Witte wrote:
> Public bug reported:
>
> I'm encountering an error message while running n_calchep for a very
> simple model in which a Z' couples to first generation leptons (with
> purely vectorial couplings) and to a dirac dark matter candidate (with
> purely vectorial couplings). When the ratio of the dark matter coupling
> to standard model coupling is large (ie one has a dark sector-like
> model), and when the Z' mass is less than about 2 \times 10^3 M_{dark
> matter} (for example, take the dark matter mass of 3 TeV, the Z' mass of
> 0.1 GeV, dark matter couplings of 1, and SM couplings of 0.1), I find an
> error in the calculation of the cross section, with the error message
> reading 'Lost of precision in SQME'. I've tried adjusting things like
> the precision of the calculation, and I've tested this with 3 different
> model files (written by 3 different individuals).
>
> Have you encountered a problem like this before, and if so is there an
> easy fix?
>
> Thank you!
>
> ** Affects: calchep
> Importance: Undecided
> Status: New
>
--
______________________________________________________________________
Prof. Alexander S Belyaev (<email address hidden>)
https://www.hep.phys.soton.ac.uk/content/alexander-belyaev

School of Physics & Astronomy, University of Southampton
Office 5047, SO17 1BJ, TEL: +44 23805 98509, FAX: +44 23805 93910
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Particle Physics Department, Rutherford Appleton Laboratory
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