[Clas_offline] Question about CLAS6 electron id

[Stepan Stepanyan]

Iulia,

The status word is more complex than just "out of time particle". By the 
way out of time means
it came either way early (faster than speed of light) or came way late 
(very slow could not happen).
In general the absolute value of the status word shows how many detector 
element were involved
in the reconstruction of the particle, for example, good electron should 
have status=4, it should
have hits in all four CLAS detector, DC, CC, SC, and EC.
The sign of the status word shows if it is a legitimate particle, >0 is 
necessary for real particles.
A value <0 means problem, no particle with status<0 must be used in the 
analysis. If it is charged
particle the most probable cause of status<0 can be track fitting, it 
ussualy means that track was fit
in hit based tracking but did not pass the time based track, and that 
could mean it was a "ghost" track.

So, Yes, you should always check the status of the particle and use only 
particles hat have STATUS>0.
This is mandatory to get real particles.

Stepan

On 10/27/14, 10:46 PM, skorodum at jlab.org wrote:
> Dear All,
>
> does anyone know what Status variable in EVNT bank mean? In bank
> description it is written the following:
>
>   18  Status   I     0   0xFFFF   ! Status word (=0 out of time particle)
>
>
> What does "out of time particle" means? It looks like that it never 0
> (typically it is 2, 3, 4 or -2, -3, -4).
>
> I am asking, because usually for preliminary electron id we require
> DCstat(1)>0, CCstat(1)>0, SCstat(1)>0, ECstat(1)>0, Charge(1)=-1 (from
> EVNT bank), but some people also require Status(1)>0.
>
> Thank you.
>
> Best regards,
> Iuliia.
>
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