[Rivet] Transverse Mass for WFinder

[Andy Buckley]

On 25/07/11 16:46, Andy Buckley wrote:
> On 25/07/11 16:40, Gavin Hesketh wrote:
>> Hi,
>> the WFinder in Rivet currently allows you to set a min and max mass.
>> These should (in 99% of W analyses) be cuts on the transverse mass, not
>> the full invariant mass.
>> Can these mass cuts be changed by default to operate on the transverse
>> mass? Or add some flag to the WFinder to switch between transverse and
>> full mass? Or even just add the transverse mass as a method for the
>> InvariantMassFinalState?
>
> Hi Gavin,
>
> Thanks for the pointer... I'll change the WFinder to make the cuts on
> the transverse mass.
>
> I don't want to mess with other projection interfaces too much before
> version 2.0, since I want to introduce a general set of "momentum
> selecting" objects to replace the current (incomplete) plethora of
> different constructor arguments, properties, methods, etc. ... you'll
> see what I mean when it appears ;)

Hmm, on looking at this in more detail, I couldn't find a less invasive 
way of doing this than to add a useTransverseMass flag to the 
InvMassFinalState and to always use that in the WFinder implementation. 
It's in the Rivet trunk now.

I also added massT and massT2 methods to the Rivet FourMomentum, for 
getting hold of the transverse mass... this will force a complete 
rebuild of any checked-out Rivets, unfortunately! Just to be completely 
sure, Gavin, by "transverse mass" you mean mT = sqrt(E^2 - |p|^2) * 
sin(theta) where theta is the usual polar angle w.r.t. the z-axis, cf. Et?

Cheers,
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
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