[Rivet] FHerwig in Agile

[Andy Buckley]

Phew -- turns out that this is ok, provided that the HERWIG PRSOF 
parameter is set to a small value, O(0.0-0.1). The default is 1, hence 
the large effect that I saw. An updated plot is attached. Thanks to Jon, 
Holger and Claire Gwenlan for helping to sort this out in my mind!

I've reinstated the soft UE calls in the JIMMY interfaces and made a 
1.3.0beta1 tarball -- hopefully we can turn this into a shiny new AGILe 
release in a few days.

Andy


On 20/07/11 10:19, Andy Buckley wrote:
> On 19/07/11 15:58, Andy Buckley wrote:
>> 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?
>
> Argh, I just tried running JIMMY out of the box with the soft UE call
> included in the AGILe interface, and with it taken out: the effect on an
> ATLAS 7 TeV UE observable is attached. I'll save you the trouble of
> looking at it.
>
> If the soft UE *should* be switched off when running JIMMY, then all
> HERWIG+JIMMY UE tunes made using AGILe are wrong -- I checked AGILe
> 1.2.1 and it contains the same call. I don't know if e.g. the ATLAS ones
> were tested with the ATLAS Herwig interface before production... I'll
> follow up on that. Of course, if the soft UE *should* be used at the
> same time as JIMMY, we're fine, but I get the feeling that that ain't
> how it's meant to work :(
>
> We should get a definitive answer before making the next beta tarball...
> asap. Does anyone know for sure?
>
> Andy
>


-- 
Dr Andy Buckley
SUPA Advanced Research Fellow
Particle Physics Experiment Group, University of Edinburgh

The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

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