[Rivet] Access to transverse and longitudinal impact parameters

[Markus Radziej]

Hi all,

Thanks for the answer. I'll have a look to see if this will work well 
with the analysis I am supposed to implement!

Cheers,
Markus

On 07/08/2014 08:39 PM, Andy Buckley wrote:
> On 07/07/14 12:53, Leif Lönnblad wrote:
>> Sorry, I thought you were talking about another kind of impact
>> parameters (the heavy-ion kind), so forget what I said before.
> I had the same reaction!
>
> [By the way, I didn't see Markus in the recipient lists of Leif's
> emails, so have added him again. If you didn't get the previous emails,
> Markus, the suggestion is in the next quoted block:]
>
>> However, assuming now that you are interested in production/decay
>> vertices, the information is still available through the underlying
>> GenEvent object. For a given Rivet::Particle, you can access the
>> underlying GenParticle and its production_vertex(). If the generator has
>> provided vertex positions they are available there.
> I would like very much to improve the Rivet Particle class for use in
> hadron decay analyses (I guess this is for B physics or similar?), but
> have been cautious about adding new facilities to the interface when I
> don't know how they would work best.
>
> There are a few features available, listed under "Decay info" on the doc
> page: http://rivet.hepforge.org/code/dev/a00222.html
> The closest available is flightLength() (which returns -1 as an obvious
> invalid value if the particle is stable or a beam particle) but I
> avoided adding prodPos() and decayPos() methods because it's less
> obvious what an invalid 3- or 4-vector should look like.
>
> If there is enthusiasm for the idea, I could add a prodPos() function,
> since all particles other than beams will have production positions and
> it's rare for analyses to handle beam particles directly. I'm more
> hesitant about adding decayPos() [or any other name for that concept --
> not all end vertices are _decays_, but the physical ones are and I think
> it's the least confusing name] because the majority of particles handled
> by analysis code are stable and hence don't have a decay position.
>
> Suggestions are very welcome, as are code patches!
>
> Andy
>
>
>
>> On 2014-07-07 13:28, Markus Radziej wrote:
>>> Hi,
>>>
>>> I was wondering if there is some way to access the impact parameter
>>> information via Rivet? I have tried looking into other analyses, but
>>> could not find one that works with these variables. I'm not quite sure
>>> the information even exists, so I decided to write an email.
>>>
>>> Thanks for your help,
>>> Markus Radziej
>>> _______________________________________________
>>> Rivet mailing list
>>> Rivet at projects.hepforge.org
>>> https://www.hepforge.org/lists/listinfo/rivet
>>
>> _______________________________________________
>> Rivet mailing list
>> Rivet at projects.hepforge.org
>> https://www.hepforge.org/lists/listinfo/rivet
>