اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدExtraction of the Neutron Electric Form Factor from Measurements of Inclusive Double Spin Asymmetries
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$[Background]$ Measurements of the neutron charge form factor, $G^n_E$, are challenging due to the fact that the neutron has no net charge. In addition, measurements of the neutron form factors must use nuclear targets which require accurately accounting for nuclear effects. Extracting $G^n_E$ with different targets and techniques provides an important test of our handling of these effects. $[Purpose]$ The goal of the measurement was to use an inclusive asymmetry measurement technique to extract the neutron charge form factor at a four-momentum transfer of $1~(rm{GeV/c})^2$. This technique has very different systematic uncertainties than traditional exclusive measurements and thus serves as an independent check of whether nuclear effects have been taken into account correctly. $[Method]$ The inclusive quasi-elastic reaction $^3overrightarrow{rm{He}}(overrightarrow{e},e)$ was measured at Jefferson Lab. The neutron electric form factor, $G_E^n$, was extracted at $Q^2 = 0.98~(rm{GeV/c})^2$ from ratios of electron-polarization asymmetries measured for two orthogonal target spin orientations. This $Q^2$ is high enough that the sensitivity to $G_E^n$ is not overwhelmed by the neutron magnetic contribution, and yet low enough that explicit neutron detection is not required to suppress pion production. $[Results]$ The neutron electric form factor, $G_E^n$, was determined to be $0.0414pm0.0077;{(stat)}pm0.0022;{(syst)}$; providing the first high precision inclusive extraction of the neutrons charge form factor. $[Conclusions]$ The use of the inclusive quasi-elastic $^3overrightarrow{rm{He}}(overrightarrow{e},e)$ with a four-momentum transfer near $1~(rm{GeV/c})^2$ has been used to provide a unique measurement of $G^n_E$. This new result provides a systematically independent validation of the exclusive extraction technique results.
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Measurements of the electric and the magnetic neutron form factors have been performed at the Mainz Microtron for more than 20 years. These MAMI experiments are reviewed in the context of measurements from other groups, and future measurements at MAMI are outlined.
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