اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMeasurement of the neutron charge radius and the role of its constituents
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The neutron is a cornerstone in our depiction of the visible universe. Despite the neutron zero-net electric charge, the asymmetric distribution of the positively- (up) and negatively-charged (down) quarks, a result of the complex quark-gluon dynamics, lead to a negative value for its squared charge radius, $langle r_{rm n}^2 rangle$. The precise measurement of the neutrons charge radius thus emerges as an essential part of unraveling its structure. Here we report on a $langle r_{rm n}^2 rangle$ measurement, based on the extraction of the neutron electric form factor, $G_{rm E}^{rm n}$, at low four-momentum transfer squared $(Q^2)$ by exploiting the long known connection between the $N rightarrow Delta$ quadrupole transitions and the neutron electric form factor. Our result, $langle r_{rm n}^2 rangle = -0.110 pm0.008~({rm fm}^2)$, addresses long standing unresolved discrepancies in the $langle r_{rm n}^2 rangle$ determination. The dynamics of the strong nuclear force can be viewed through the precise picture of the neutrons constituent distributions that result into the non-zero $langle r_{rm n}^2 rangle$ value.
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