[Eg6_analysis] .....

[Stepan Stepanyan]

Hi Eric,

Sorry for responding to your question about the form of the Mx2 that Yohann
has this late. I finally found some time and made some simulations, just the
kinematics, of real photon electroproduction reaction with different 
hadronic
final states. So the reaction I simulated is, e 4^He -> e' \gamma X, 
where X was -
1) ppnn (breakup to four nucleons)
2) pnd (breakup to two nucleons and deuterium)
3) p3H (breakup to a proton and triton)
4) p3H-spectator (scattering on a proton and the triton is a spectator)

Attached plot shows superposition of missing mass squared of the final 
state
electron and the photon from all these reactions, assuming that the 
target is 4He,
basically mass square of system X. I required that the electron and the 
photon
have momentum and \theta in the CLAS acceptance region, and also required
that none of hadrons had kinematics in the CLAS detection region (very 
simple
but should be Ok for this studies).
In the graph, the forward peak at Mx2~15 GeV2 is from (4), little bump 
at ~20 GeV2
is from (3). (1) peaks at very large Mx2 and  (2) is distributed in the 
middle. As you
can see there is a "peak" from two body breakup and looks to me that is 
what Yohann
sees. I do not have relative weights of these reactions, but I am sure 
one can work
this out and match experimentally observed spectrum with simulations 
(one should
include also pi0 production).

Regards, Stepan

On 3/22/11 10:31 AM, Eric Voutier wrote:
> It seems I lost phone connection while I was talking.... It does not 
> work at all by now
>
> My main question was about the position of tyhe small bump we are 
> seeing in Mx2,
> any idea about the origin of this ??
>
> Thanks, eric
>
>
> _______________________________________________
> Eg6_analysis mailing list
> Eg6_analysis at jlab.org
> https://mailman.jlab.org/mailman/listinfo/eg6_analysis
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