[EvtGen] S-wave with EvtGen

[John Back]

Hi Giacomo,

On 16/07/18 10:12, Giacomo Fedi wrote:
> Hi EvtGen authors,
>
> I'm a CMS b-analyst.
>
> I was wondering if it is now possible to produce samples of P+S wave
> in the JpsiPhi decay. In principle we would need an improved PVV_CPLH
> model which right now is simulating only the P-wave.
>

No, there is not an improved model that can do this, as far as I am aware.

> Long time ago I attended a EvtGen workshop where Blake showed some
> slides about the future plans:
>
> https://indico.cern.ch/event/290370/timetable/#20140123
>
> it was 2014, do you have any update on that? I'm also wondering about
> the "internal" model repository mentioned at slide 7; we could be
> interested on some improved models you might have developed in the
> meanwhile.
>

Unfortunately, LHCb still has these models in the EvtGenExtras package. 
But I think that most of them can move to the main EvtGen repository. 
However, I believe the K* ll "Durham" model will not be available in the 
future, since it depends on GSL for numerical integration methods (an 
external dependency that we don't really want to add) and LHCb does not 
use it for any signal decay generation anyway, as far as I can tell, so 
you are not missing out on anything here.

I will start a discussion within LHCb to ask if its sensible/OK to move 
the extra models; we can then simply copy the code to the HepForge 
repository

https://evtgen.hepforge.org

and they will then be available for future releases (via HepForge and 
the periodic Genser installations at Cern).

We (Tom Latham) gave an EvtGen status report at the CMS heavy flavour 
tagging workshop in April this year, based on what's available in the 
HepForge repository:

https://indico.cern.ch/event/695320/contributions/2850954

Do you know what version of EvtGen is CMS using for MC production?

Regards,
	John.