[Rivet] Rivet plugin ALICE_2014_I1300380

[Enrico Fragiacomo]

When we calculate the efficiency correction, we do the following in the MC:

- we generate a number N_genMC of Sigma(1385);
- the daughter particles (Lambda's and pions) are fed to GEANT3 which 
simulates the response of the detector (including losses due to 
inefficiencies, acceptance, ...);
- simulated data are analyzed as real data (including applying kinetic 
cuts to daughter and grand-daughter particles);
- at the end, we count the number N_recMC of reconstructed Sigma(1385).

The correction factor to be used with real data is N_genMC /N_recMC. 
This is done for every pT-interval.

So, the final yields are corrected for the kinetic cuts on the daughter 
particles and can be directly compared (for 0.7<pT<6.0 GeV/c) to a model 
without kinetic cuts.

Regards,
Enrico


On 07/02/2015 03:28 PM, Holger Schulz wrote:
> On 02/07/15 14:26, Enrico Fragiacomo wrote:
>> Hello Holger,
>>
>> in the data analysis, the final pT distributions are corrected with 
>> the Montecarlo for the inefficiencies like those due to the kinetic 
>> cuts on the daughter particles (and also for the acceptance,...). 
>> This is described in Section 2.3 in the paper. This holds for those 
>> pT bins where we are able to extract the signal.
>>
>> The fact that e.g. for the Sigma(1385) we do not have spectra points 
>> below 0.7 GeV/c is in fact due to the large inefficiency at low pT 
>> which makes impossible to extract the Sigma(1385) signal. In order to 
>> measure the total yield (dN/dy) or the mean pT (<pT>), an 
>> extrapolation of the spectrum to pT=0 is performed. This is described 
>> in Section 3 of the paper.
>>
>
>> Does this answer your question?
> Hmm, not sure what to do then. So when you were unfolding, did the 
> truth/hadron level definition have a pT cut or not?
>
> Thanks,
> Holger
>> Thank you.
>> Enrico
>>
>>
>> On 07/02/2015 02:56 PM, Holger Schulz wrote:
>>> Hi,
>>>
>>> we are about to release Rivet 2.3.0 and are currently going over the 
>>> list of not
>>> yet included analyses.
>>>
>>> Looking at your analysis I do not quite understand the kinematic 
>>> cuts applied at
>>> hadron level. In the publication there is a table "common cuts" that 
>>> lists a pT
>>> cut of 0.15 GeV for all selected particles.
>>>
>>> Then in you final plots, the pT distributions appear to have a cut of
>>> pT>1 GeV. The plugin, however, does not have a pT cut whatsoever.
>>>
>>> Could you please clarify this? Otherwise I can only include your 
>>> analysis
>>> marked as "UNVALIDATED" in the next release.
>>>
>>> Thanks,
>>> Holger
>>
>

-- 
Enrico Fragiacomo
INFN - Sezione di Trieste
via Valerio 2, 34127 Trieste, Italy
tel./fax. +39-040-5583392