[Rivet] Rivet Query

[Andy Buckley]

Hi Debarati,

I will see if I can provide a calc() method on Hemispheres which will
accept a vector of FourMomentum. You could that way assemble whatever
you wanted as the input, with z components as original or zeroed. I'll
let you know how that goes.

I'll also look into providing an M2sum method.

Andy


On 15/08/14 11:01, Debarati Roy wrote:
> Hi Andy, Thanks for your feedback. First of all I would like to give
> you some more information regarding these hadronic event shape
> calculations applied in this analysis.
> 
> In this analysis for the calculation of the five hadronic event
> shapes always the input variables we used are jet Px, Py, Pz and E.
> In some of them we do not require that Pz component like the thrust,
> total jet broadening.
> 
> Now regarding your comments, For the total jet broadening I think
> your calc method can be useful since we have used only transverse
> component of momentum along with jet eta and phi. But for the total
> jet mass the concept is very similar as  used in Hemispheres.cc for
> mass2With and mass2Against. The difference exists in the input(always
> jet's four momentum) and then total jet mass is the sum of  mass2With
> and mass2Against(this one I called as M2sum() in my previous mail).
> For the total transverse jet mass I think the same method can work
> only again in transverse plane(Z component set to 0).  So over all I
> would say the jet hemisphere projection will cover all:
> broadening(setZ=0), total jet mass, total transverse jet mass(setZ=0)
> with jet's four momentum as inputs. If the jet hemisphere  you do not
> think should be added as a projection then I can try with the
> analysis code.
> 
> Please let us know your view.
> 
> Regards, Debarati ________________________________________ From: Andy
> Buckley Sent: 15 August 2014 01:09 To: Debarati Roy;
> rivet at projects.hepforge.org Cc: Albert Knutsson; Maxime Gouzevitch;
> Lars Sonnenschein Subject: Re: [Rivet] Rivet Query
> 
> Hi Debarati,
> 
> Those hemispheres are an e+e- observable, so I'm a bit surprised that
> a non-transverse decomposition work at a hadron collider... but then
> I'm not a hadronic event shapes expert. Are you using the jets to
> build a "3D" hemispheres observable, or do you want to set the jet
> z-components to zero and then run the hemispheres algorithm?
> 
> If the latter, I guess we could expose a "calc()" method on the 
> projection so it can be used directly rather than via applyProjection
> -- this is sometimes done with the FastJets projection, for example.
> 
> If the former, then maybe we should supply a JetHemispheres
> projection instead. It might be easier to just implement in the
> analysis code, though, since projections are only really necessary
> for code that's likely to appear in several analyses and which would
> benefit from caching.
> 
> I'd be happy to add a M2sum() method if you can define what it should
> do.
> 
> Cheers, Andy
> 
> 
> On 14/08/14 16:10, Debarati Roy wrote:
>> Hi Experts, I need some feedback regarding an analysis which we
>> are planning to introduce in Rivet. It is a CMS analysis consists
>> of the study of hadronic event shapes (arxiv link : 
>> http://arxiv.org/abs/arXiv:1407.2856). In this analysis five event
>> shapes are studied, thrust, total jet broadening, total jet mass,
>> total transverse jet mass, jet resolution parameter where each of
>> the event shape variable is calculated by giving the input of final
>> state jets momenta . I found that Rivet already has the thrust
>> projection where jets momenta of an event can be given as input to
>> calculate thrust.  But for other three variables (total jet 
>> broadening, total jet mass, total transverse jet mass) I observed
>> that you have a similar but not identical projection named, 
>> https://rivet.hepforge.org/trac/browser/src/Projections/Hemispheres.cc
>>
>> 
In this projection you are taking the final state particles to calculate
>> broadening and mass if I am not wrong whereas in this analysis the
>> final state jets momenta are used. So is it possible to modify the
>> existing projection to be more flexible so that we can run it over
>> the final state jets too? Or is it possible that a different
>> projection with a different name can be added? Also here 
>> https://rivet.hepforge.org/trac/browser/include/Rivet/Projections/Hemispheres.hh
>>
>> 
I could see that there exists different methods  M2high(), M2low(),
>> M2diff(). Is it possible to introduce M2sum() as per this analysis 
>> requirement?
>> 
>> Please let us know.
>> 
>> Thanks, Debarati
>> 
>> 
>> _______________________________________________ Rivet mailing list 
>> Rivet at projects.hepforge.org 
>> https://www.hepforge.org/lists/listinfo/rivet
>> 
> 
> 
> -- Dr Andy Buckley, Royal Society University Research Fellow Particle
> Physics Expt Group, University of Glasgow / PH Dept, CERN
> 


-- 
Dr Andy Buckley, Royal Society University Research Fellow
Particle Physics Expt Group, University of Glasgow / PH Dept, CERN

-- 
Dr Andy Buckley, Royal Society University Research Fellow
Particle Physics Expt Group, University of Glasgow / PH Dept, CERN