[Rivet] Problems when simulating an analysis

[Chiara Zampolli]

Hi Andy,

On Apr 19, 2013, at 12:07 PM, Andy Buckley wrote:

> On 19/04/13 11:25, Chiara Zampolli wrote:
>> Hi James,
>> 
>> One more question. On the web
>> page http://rivet.hepforge.org/code/dev/a00140.html I see the
>> documentation for the ChargedFinalState. I have a doubt about the
>> minimum eta value: here you find:
>> 
>> ChargedFinalState <http://rivet.hepforge.org/code/dev/a00140.html> 	(
>> double  	/mineta/ = |-MAXRAPIDITY
>> <http://rivet.hepforge.org/code/dev/a00611.html#a2b7b3b854d8a789b4f8479ad849f29a7>|,
>> 
>> 		double  	/maxeta/ = |MAXRAPIDITY
>> <http://rivet.hepforge.org/code/dev/a00611.html#a2b7b3b854d8a789b4f8479ad849f29a7>|,
>> 
>> 		double  	/minpt/ = |0.0*GeV
>> <http://rivet.hepforge.org/code/dev/a00611.html#aec0e126d9991db8ad0b26139f5860568>| 
>> 
>> 	) 		
>> 
>> 
>> In my analysis I defined:
>> 
>> ChargedFinalState cfs15(-0.8, 0.8, 0.15);
>> 
>> Shuold the first number be also positive? I need particles in [-0.8, 0.8].
> 
> No, it should be negative. You can use e.g. cfs15(-0.1, 0.8, 0.15) to
> select only particles in a non-central region on one side of the
> detector if you really want! (We're hoping to make this a bit more
> powerful in future, but the implementation requires using some C++
> features that aren't yet in widespread HEP production use.)

Ok, so I do it correctly. 

> 
>> Moreover, from here I think that the "*GeV" is not strictly needed, but
>> I will add to be on the safe side.
> 
> It should definitely be added. I forget the exact units behaviour at the
> moment -- I think we convert the incoming HepMC event to have GeV as the
> base unit, but this isn't guaranteed to work forever. Plus, the code is
> more humanly readable when the "*GeV" is there! The same thing applies
> to using "/GeV" (or "/MeV", or whatever) when filling histograms with
> dimensionful quantities.
> 

Ok, I will do it. First, let's see if I manage to understand the settings for the generator…

	Cheers,

		Chiara