High-precision measurement of the proton elastic form factor ratio μpGE/GM at low Q2
- Zhan, X.
- Allada, K.
- Armstrong, D.S.
- Arrington, J.
- Bertozzi, W.
- Boeglin, W.
- Chen, J.-P.
- Chirapatpimol, K.
- Choi, S.
- Chudakov, E.
- Cisbani, E.
- Decowski, P.
- Dutta, C.
- Frullani, S.
- Fuchey, E.
- Garibaldi, F.
- Gilad, S.
- Gilman, R.
- Glister, J.
- Hafidi, K.
- Hahn, B.
- Hansen, J.-O.
- Higinbotham, D.W.
- Holmstrom, T.
- Holt, R.J.
- Huang, J.
- Huber, G.M.
- Itard, F.
- de Jager, C.W.
- Jiang, X.
- Johnson, M.
- Katich, J.
- de Leo, R.
- LeRose, J.J.
- Lindgren, R.
- Long, E.
- Margaziotis, D.J.
- May-Tal Beck, S.
- Meekins, D.
- Michaels, R.
- Moffit, B.
- Norum, B.E.
- Olson, M.
- Piasetzky, E.
- Pomerantz, I.
- Protopopescu, D.
- Qian, X.
- Qiang, Y.
- Rakhman, A.
- Ransome, R.D.
- Reimer, P.E.
- Reinhold, J.
- Riordan, S.
- Ron, G.
- Saha, A.
- Sarty, A.J.
- Sawatzky, B.
- Schulte, E.C.
- Shabestari, M.
- Shahinyan, A.
- Shneor, R.
- Širca, S.
- Solvignon, P.
- Sparveris, N.F.
- Strauch, S.
- Subedi, R.
- Sulkosky, V.
- Vilardi, I.
- Wang, Y.
- Wojtsekhowski, B.
- Ye, Z.
- Zhang, Y.
DOIAbstract
AbstractWe report a new, high-precision measurement of the proton elastic form factor ratio μpGE/GM for the four-momentum transfer squared Q2=0.3–0.7(GeV/c)2. The measurement was performed at Jefferson Lab (JLab) in Hall A using recoil polarimetry. With a total uncertainty of approximately 1%, the new data clearly show that the deviation of the ratio μpGE/GM from unity observed in previous polarization measurements at high Q2 continues down to the lowest Q2 value of this measurement. The updated global fit that includes the new results yields an electric (magnetic) form factor roughly 2% smaller (1% larger) than the previous global fit in this Q2 range. We obtain new extractions of the proton electric and magnetic radii, which are 〈rE2〉1/2=...
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