[Rivet] FHerwig in Agile

[Andy Buckley]

Hi Gavin,

Thanks for that... I've made that fix in FHerwig, FHerwigJimmy, and the 
AlpGen* variants of both of those. I'm wondering, though, *should* the 
soft UE be being called in the Jimmy variants? I suspect not... and 
wonder how much of an effect this has on UE observables :S Anyone know 
for sure?

We'll get this into the next release... hopefully very soon, since I 
think that only the Cascade issue that Holger's looking at, and maybe 
this JIIMY+soft UE thing are left to be fixed before tagging & tarring 
AGILe 1.3.0.

Andy


On 19/07/11 14:45, Gavin Hesketh wrote:
> Hello,
> I noticed a problem when trying to run Herwig without hadronisation. It
> seems the soft underlying event has to be turned off also, otherwise
> Herwig is never able to produce events.
>
> ie:
>
> if (_doHadronise) {
> FC_HWCFOR(); // Do cluster formation
> FC_HWCDEC(); // Do cluster decays
> FC_HWDHAD(); // Do unstable particle decays
> FC_HWDHVY(); // Do heavy flavor decays
> }
>
> FC_HWMEVT(); // Add soft underlying event
> FC_HWUFNE(); // Finish event
> if (FC_HWEVNT.IERROR == 0) break;
>
>
> the call to FC_HWMEVT() needs to be moved into the _doHadronise
> conditional in order to get any events.
>
> This is an empirical observation, I don't really understand what happens...
>
> FHerwig.cc and FHerwigJimmy.cc both need to be updated.
>
> cheers,
> Gavin
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-- 
Dr Andy Buckley
SUPA Advanced Research Fellow
Particle Physics Experiment Group, University of Edinburgh

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