Difference between revisions of "07/07/2020"
(Created page with "Present: M.D., A.D., J.S., S.Š General: M.D: S.Š: (By email): I have coded the unpolarized Bethe-Heitler cross-section for a nuclear (carbon) target, and the result is sh...") |
m |
||
| Line 5: | Line 5: | ||
M.D: | M.D: | ||
| − | S.Š: (By email): I have coded the unpolarized Bethe-Heitler cross-section for a nuclear (carbon) target, and the result is shown in [https://halldweb.jlab.org/wiki/images/9/97/Cp_07_07_2020.pdf the attached figure] in orange: the elastic part (dotted), the elastic+quasielastic (dashed) and the elastic+quasielastic+inelastic = total (full curve). I used the parameterizations (B49), (B52,53) and (B56,57) from Tsai (1974). | + | S.Š: (By email): |
| + | |||
| + | I have coded the unpolarized Bethe-Heitler cross-section for a nuclear (carbon) target, and the result is shown in [https://halldweb.jlab.org/wiki/images/9/97/Cp_07_07_2020.pdf the attached figure] in orange: the elastic part (dotted), the elastic+quasielastic (dashed) and the elastic+quasielastic+inelastic = total (full curve). I used the parameterizations (B49), (B52,53) and (B56,57) from Tsai (1974). | ||
| + | |||
Now how does that compare to the free proton case? For now the only meaningful comparison I was able to make was in the elastic part. Assuming (B49) for the nuclear elastic form-factor I learn that this scales as mass*Z^2 (!!!). So I have multiplied the elastic part of free-proton Bethe-Heitler by 12*36 (!!!) and got | Now how does that compare to the free proton case? For now the only meaningful comparison I was able to make was in the elastic part. Assuming (B49) for the nuclear elastic form-factor I learn that this scales as mass*Z^2 (!!!). So I have multiplied the elastic part of free-proton Bethe-Heitler by 12*36 (!!!) and got | ||
the green dotted line. | the green dotted line. | ||
| + | |||
Am I telling you that we should have multiplied the proton BH cross-sections by 12*36 = 432 instead of 6 or 12 ?? | Am I telling you that we should have multiplied the proton BH cross-sections by 12*36 = 432 instead of 6 or 12 ?? | ||
I was hoping that the target mass ("mi" in the paper) cancels somewhere, but it does not seem so. In Eq. (2.1), for instance, there is a mi in the numerator, but (k*pi) in the denominator is just Egamma*mi, so both mi cancel. So there is this unfortunate 12 in the form-factor and there is a 36 factor due to the charge in (B49), I am afraid, unless I am missing something. | I was hoping that the target mass ("mi" in the paper) cancels somewhere, but it does not seem so. In Eq. (2.1), for instance, there is a mi in the numerator, but (k*pi) in the denominator is just Egamma*mi, so both mi cancel. So there is this unfortunate 12 in the form-factor and there is a 36 factor due to the charge in (B49), I am afraid, unless I am missing something. | ||
| + | |||
It is harder to compare the inelastic parts on the same plot, as these scale linearly with Z, as in (B52,53) and (B56,57). | It is harder to compare the inelastic parts on the same plot, as these scale linearly with Z, as in (B52,53) and (B56,57). | ||
Revision as of 13:27, 7 July 2020
Present: M.D., A.D., J.S., S.Š
General:
M.D:
S.Š: (By email):
I have coded the unpolarized Bethe-Heitler cross-section for a nuclear (carbon) target, and the result is shown in the attached figure in orange: the elastic part (dotted), the elastic+quasielastic (dashed) and the elastic+quasielastic+inelastic = total (full curve). I used the parameterizations (B49), (B52,53) and (B56,57) from Tsai (1974).
Now how does that compare to the free proton case? For now the only meaningful comparison I was able to make was in the elastic part. Assuming (B49) for the nuclear elastic form-factor I learn that this scales as mass*Z^2 (!!!). So I have multiplied the elastic part of free-proton Bethe-Heitler by 12*36 (!!!) and got the green dotted line.
Am I telling you that we should have multiplied the proton BH cross-sections by 12*36 = 432 instead of 6 or 12 ?? I was hoping that the target mass ("mi" in the paper) cancels somewhere, but it does not seem so. In Eq. (2.1), for instance, there is a mi in the numerator, but (k*pi) in the denominator is just Egamma*mi, so both mi cancel. So there is this unfortunate 12 in the form-factor and there is a 36 factor due to the charge in (B49), I am afraid, unless I am missing something.
It is harder to compare the inelastic parts on the same plot, as these scale linearly with Z, as in (B52,53) and (B56,57).
J. S.:
A. D.:
