[Halld-physics] Primakov eta hadronic background

[Eugene Chudakov]

The first thing to check was the real-eta background.
The combinatorial (not eta) background can be subtracted
using the mass sidebands. The error coming from this
subtraction has to be evaluated. Hopefully, there are not many
combinations at a large elasticity.

Will someone lead a discussion on the error budget proposed?

Eugene

On Wed, 2 Dec 2009, Richard Jones wrote:

> Alex,
>
> Thank you for the quick study you did.  However I am puzzled by the suggested 
> conclusion.  By combinatorial background, one means etas that are 
> reconstructed out of photons that did not come from an eta.  Maybe this is 
> small, but it is going to take considerable work to show it.
>
> Alexander Somov wrote:
>> ( The inclusive eta background should dominate combinatorial bg)
>> 
> ... in light of ...
>> (I selected events containing at least one eta in the final
>> state  with an angle < 1.6 deg, and processed these events
>> through Geant).
>> 
> To study the combinatoric background you need to look at the inclusive 
> sample.  Why should you require an eta if you are looking for 2gamma 
> combinatorial background under the eta?  I believe this restriction can lead 
> to a severe underestimate of the combinatorial background under the eta.
>
> -Richard Jones
>
>