[Rivet] finalstate projection with assymetric beam

[Andy Buckley]

Thanks for the information -- we can certainly provide something. So the 
centre-of-mass frame is to be the centre-of-mass of the incoming 
particle system rather than something computed from a final state with 
acceptance cuts. Should be straightforward for us to add.

Good to have feedback and suggestions!

Best wishes,
Andy


On 18/01/16 10:37, Pierog, Tanguy (IKP) wrote:
> 	Hi Andy,
>
>
>> The only existing projection that does that is DISKinematics, I think.
>> We could make a projection like you mention, but everything that
>> projections do can also be done inside an analysis code, and since there
>> has not previously been a request for that functionality there was no
>> incentive for us to make a new feature that no-one wanted! But if you
>> would find this useful in *several* analyses -- so there is a chance of
>> some benefit from result caching as well as simplifying several analysis
>> codes -- then we can take this a bit further.
>>
>
> 	The point is that many fixed target experiments plot the various observables
> in the center-of-mass frame (like rapidity or xf). So yes this will be used
> by several analysis and if you want RIVET to be used not only at LHC (there
> is still a lot of fixed target experiment at SPS or in other lab) this would
> be useful to help these collaboration to include their analysis in RIVET.
> Since we are involved in NA61 for instance I can push my colleagues to put
> their analysis on RIVET for instance.
>
>
>> We will probably need to iterate a bit to understand how the CoM frame
>> is to be defined, and whether it also needs to include some rotation
>> into a conventional alignment cf. our built-in HERA transformation.
>>
>
> 	We can have a look at what is done in DISKinematics and try something
> ourself. It should not be complicated but it would be cleaner to have generic
> projection. In that case the CoM is simple (just the same projectile and
> target but boosted) and there is no a priori convention here (but technically
> the "exotic" particle is always the projectile but it is the same in the
> models).
>
>
>>> 	Actually I have the same question about the analysis we are doing. They
>>> are based on old data (80's and 90's) from collaboration which are not
>>> existing anymore. What is the policy in that case. Can it be distributed
>>> or should it get some approval from someone ? Do you have any idea ?
>>
>> We don't enforce a policy about analyses needing to be approved by
>> experiments, particularly not defunct ones. We just much *prefer* that
>> analyses being provided during an experiment's lifetime be written, or
>> at least be approved by that experiment, but an unofficial analysis is
>> far better than nothing. We'll happily take anything you provide!
>>
>
> 	OK thanks. For the moment it is just a topic for bachelor student, but we
> find manpower we would like to increase our data base and why not putting it
> online.
>
> 	best regards
>
> 		Tanguy
>


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