Dispersive corrections in elastic electron-nucleus scattering: an investigation in the intermediate energy regime and their impact on the nuclear matter

• Published in: The European physical journal. A, Hadrons and nuclei Vol. 56; no. 5
• Main Authors: Guèye, P., Kabir, A. A., Giuliani, P., Glister, J., Lee, B. W., Gilman, R., Higinbotham, D. W., Piasetzky, E., Ron, G., Sarty, A. J., Strauch, S., Adeyemi, A., Allada, K., Armstrong, W., Arrington, J., Arenaövel, H., Beck, A., Benmokhtar, F., Berman, B. L., Boeglin, W., Brash, E., Camsonne, A., Calarco, J., Chen, J. P., Choi, S., Chudakov, E., Coman, L., Craver, B., Cusanno, F., Dumas, J., Dutta, C., Feuerbach, R., Freyberger, A., Frullani, S., Garibaldi, F., Hansen, J. -O., Holmstrom, T., Hyde, C. E., Ibrahim, H., Ilieva, Y., Jiang, X., Jones, M. K., Katramatou, A. T., Kelleher, A., Khrosinkova, E., Kuchina, E., Kumbartzki, G., LeRose, J. J., Lindgren, R., Markowitz, P., Beck, S. May-Tal, McCullough, E., Meekins, D., Meziane, M., Meziani, Z. -E., Michaels, R., Moffit, B., Norum, B. E., Petratos, G. G., Oh, Y., Olson, M., Paolone, M., Paschke, K., Perdrisat, C. F., Potokar, M., Pomatsalyuk, R., Pomerantz, I., Puckett, A., Punjabi, V., Qian, X., Qiang, Y., Ransome, R. D., Reyhan, M., Roche, J., Rousseau, Y., Sawatzky, B., Schulte, E., Schwamb, M., Shabestari, M., Shahinyan, A., Shneor, R., Širca, S., Slifer, K., Solvignon, P., Song, J., Sparks, R., Subedi, R., Urciuoli, G. M., Wang, K., Wojtsekhowski, B., Yan, X., Yao, H., Zhan, X., Zhu, X.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2020; Springer Nature B.V; EDP Sciences ; Springer [1998-....]; Springer
• Subjects: Beams (radiation); Born approximation; Carbon 12; Charge distribution; Diffraction; Dispersion; dispersive effects; Elastic scattering; electron scattering; Hadrons; Heavy Ions; Nuclear Experiment; Nuclear Fusion; Nuclear matter; Nuclear Physics; NUCLEAR PHYSICS AND RADIATION PHYSICS; nuclear structure; Nuclear Theory; Particle and Nuclear Physics; Physics; Physics and Astronomy; Regular Article - Experimental Physics; Scattering cross sections; Spectrometers
• ISSN: 1434-6001; 1434-601X
• DOI: 10.1140/epja/s10050-020-00135-7

Measurements of elastic electron scattering data within the past decade have highlighted two-photon exchange contributions as a necessary ingredient in theoretical calculations to precisely evaluate hydrogen elastic scattering cross sections. This correction can modify the cross section at the few percent level. In contrast, dispersive effects can cause significantly larger changes from the Born approximation. The purpose of this experiment is to extract the carbon-12 elastic cross section around the first diffraction minimum, where the Born term contributions to the cross section are small to maximize the sensitivity to dispersive effects. The analysis uses the LEDEX data from the high resolution Jefferson Lab Hall A spectrometers to extract the cross sections near the first diffraction minimum of 12 C at beam energies of 362 MeV and 685 MeV. The results are in very good agreement with previous world data, although with less precision. The average deviation from a static nuclear charge distribution expected from linear and quadratic fits indicate a 30.6% contribution of dispersive effects to the cross section at 1 GeV. The magnitude of the dispersive effects near the first diffraction minimum of 12 C has been confirmed to be large with a strong energy dependence and could account for a large fraction of the magnitude for the observed quenching of the longitudinal nuclear response. These effects could also be important for nuclei radii extracted from parity-violating asymmetries measured near a diffraction minimum.