[G12] Proton, Electron, Positron, Photon acceptance

[mpaolone at jlab.org]

MK,

Right, so you did say you generate 1/E.  Is pluto using some
energy-dependent photoproduction cross-section to generate your eta's, or
is it just phase-space?  Do you define a t-slope in the generation that
maybe favors wide-angle (or very-small angle) eta production?

-Michael


> On 7/31/12 5:26 PM, mpaolone at jlab.org wrote:
>> Ken,
>>
>> The dip is something that comes from lepton-selection process in the
>> center of the sector.  It's either due to a reduced cherenkov efficiency
>> there, or/and a poorer pion/lepton separation.  I have some plots
>> showing
>> this, but they are on my other computer which is still packed from the
>> move.  I'll post them as soon as I am up and running.
>>
>> What's more bothersome to me, is that the dip isn't represented in the
>> data.
>>
>> Also MK,
>>
>> It looks like your MC beam distribution is not Bremsstrahlung.  Are you
>> generating your beam as 1/E?  You could try to weight your events to
>> make
>> the MC and the data beam energy match, and see how that affects your
>> proton (and t) distributions.
>>
>> -Michael
>>
>>
>>> MK,
>>>
>>> Why do you have a dip in the middle of each sector for the plot labeled
>>> "phi of e+" on page 1?  (Similar for the e- on page 2).  This doesn't
>>> look
>>> correct.  What happens if you don't do the preliminary cut on leptons?
>>>
>>> Ken
>>>
>>>
>>> -----Original Message-----
>>> From: g12-bounces at jlab.org [mailto:g12-bounces at jlab.org] On Behalf Of
>>> Michael C. Kunkel
>>> Sent: Tuesday, July 31, 2012 4:12 PM
>>> To: g12
>>> Subject: [G12] Proton, Electron, Positron, Photon acceptance
>>>
>>> Greetings G12,
>>>
>>> I seem to having issues with my acceptance and would appreciate
>>> comments.
>>> Please refer to the link
>>> http://clasweb.jlab.org/rungroups/g12/wiki/index.php/PEpEmGamPhase_Acceptance#Tuesday_July_31.2C_2012
>>> where I have plots showing acceptance plots. The issue I am having is
>>> in
>>> the proton and beam acceptance, which does not match the data, however
>>> the
>>> e+e-gamma acceptance does.
>>>
>>> I generate my beam spectrum with a 1/e function and before I send into
>>> gsim I do a preliminary cut on the leptons/photons to be kinematic
>>> angles
>>> of the EC/CC. This cut is what distorts my proton, beam and t spectrum.
>>>
>>> Any thoughts on why?
>>>
>>> Thanks
>>> MK
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> Thanks Mike,
>
> I do generate with a 1/E bremstrahlung profile, however when I make the
> preliminary cuts for the leptons/final photon, this 1/E spectrum does
> not survive. This was my original question in the first email as to why
> this 1/E spectrum would distort my spectrum.
>
> MK
>