[Rivet] Transverse Mass for WFinder

[Andy Buckley]

Well, that's equivalent so I think what's in the trunk now is good. 
Thanks :)

Andy


On 25/07/11 18:06, Gavin Hesketh wrote:
> Hi Andy,
> I think that works. It's also calculated in MC_WJETS.cc for example
>
> const double transM = sqrt(ET*ET - px*px - py*py);
>
> cheers,
> Gavin
>
>
> On 25/07/11 18:02, Andy Buckley wrote:
>> 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
Scotland, with registration number SC005336.