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Hi Eric,<br>
<br>
Sorry for responding to your question about the form of the Mx2 that
Yohann <br>
has this late. I finally found some time and made some simulations,
just the<br>
kinematics, of real photon electroproduction reaction with different
hadronic <br>
final states. So the reaction I simulated is, e 4^He -> e' \gamma
X, where X was - <br>
1) ppnn (breakup to four nucleons)<br>
2) pnd (breakup to two nucleons and deuterium)<br>
3) p3H (breakup to a proton and triton)<br>
4) p3H-spectator (scattering on a proton and the triton is a
spectator)<br>
<br>
Attached plot shows superposition of missing mass squared of the
final state <br>
electron and the photon from all these reactions, assuming that the
target is 4He, <br>
basically mass square of system X. I required that the electron and
the photon <br>
have momentum and \theta in the CLAS acceptance region, and also
required <br>
that none of hadrons had kinematics in the CLAS detection region
(very simple <br>
but should be Ok for this studies). <br>
In the graph, the forward peak at Mx2~15 GeV2 is from (4), little
bump at ~20 GeV2 <br>
is from (3). (1) peaks at very large Mx2 and (2) is distributed in
the middle. As you <br>
can see there is a "peak" from two body breakup and looks to me that
is what Yohann <br>
sees. I do not have relative weights of these reactions, but I am
sure one can work <br>
this out and match experimentally observed spectrum with simulations
(one should <br>
include also pi0 production). <br>
<br>
Regards, Stepan <br>
<br>
On 3/22/11 10:31 AM, Eric Voutier wrote:
<blockquote cite="mid:4D88B2B3.6060804@lpsc.in2p3.fr" type="cite">It
seems I lost phone connection while I was talking.... It does not
work at all by now
<br>
<br>
My main question was about the position of tyhe small bump we are
seeing in Mx2,
<br>
any idea about the origin of this ??
<br>
<br>
Thanks, eric
<br>
<br>
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