[Frost] fermi momentum

[dugger at jlab.org]

Hi,

I was thinking that a proton hitting another nucleon (perhaps breaking the
other nucleon out of the nuclei or hitting yet another nucleon) would have
its momentum change in such a way as to mimic separation energy.

-Michael

>
>
> An extreme case of nucleon knockout is a complete break up of the
> nucleus. In that case, we need full binding energy, which in case of 12C
> is 92 MeV, for 16O it is about 128 MeV and for 4He about 30 MeV
>
> -Eugene
>
> Michael Dugger wrote, On 08/16/12 17:58:
>>
>> Hi,
>>
>> I made a plot that is similar to what I showed at the meeting today. The
>> only
>> difference is that I have included fermi momentum smearing. I used the
>> fermi
>> momentum to be 250 MeV and allowed the initial proton momentum to be
>> smeared
>> from 0.0 up to the fermi momentum, isotropic in space.
>>
>> The plot can be found at
>> http://www.jlab.org/Hall-B/secure/g9/ASU/fSmear.gif
>>
>> The x-axis is massX squared and the colors are as such
>> Black  -> separation energy = 12 MeV
>> Red    -> separation energy = 16 MeV
>> Green  -> separation energy = 50 MeV
>> Blue   -> separation energy = 100 MeV
>> Yellow -> separation energy = 200 MeV
>> Pink   -> separation energy = 300 MeV
>>
>> In the region that we call unphysical in the analysis note (massX^2 <
>> 0.4
>> GeV^2), the spectrum is from separation energies > 100 MeV. These
>> separation
>> energies are too large to come from simply pulling out a proton from the
>> nuclei
>> of interest. Instead, I assume, that the data we have with massX^2 < 0.4
>> GeV^2
>> is due to scattering of the proton off of another nucleon. Such an
>> effect is
>> discussed in a paper by K. Nakamura et. al. (Nucl. Phys. A 268, (1976)
>> 381-407)
>>
>> If I can make the assumption that the unphysical region is from a proton
>> scattering off another nucleon, then I can get an approximation for the
>> systematic uncertainty in the scale factors due to the different types
>> of
>> target nuclei.
>>
>> It will take a bit more writing that I want to send in an email, so I'll
>> try and make a pdf to send around tomorrow to show how I'm trying to
>> approximate the systematic uncertainty.
>>
>> Take care,
>> Michael
>>
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