[G12] Proton, Electron, Positron, Photon acceptance

[MK]

Hi Mike

I have started to weight my beam by cross section and have applied t constraints. I had originally thought this was the issue, but I did not to bias an opinion by me saying so in the original email. I'm glad you concluded on this and it wasn't something else I had missed.

BR
MK

Sent from my iPhone

On Jul 31, 2012, at 5:50 PM, mpaolone at jlab.org wrote:

> 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
>> 
>