Document Type
Article
Publication Date
2026
DOI
10.1016/j.physletb.2026.140250
Publication Title
Physics Letters B
Volume
874
Pages
140250
Abstract
We report on the first measurement of angular correlations between high-energy pions and slow protons in electron-nucleus (eA) scattering, providing a new probe of how a nucleus responds to a fast-moving quark. The experiment employed the CLAS detector with a 5-GeV electron beam incident on deuterium, carbon, iron, and lead targets. For heavier nuclei, the pion-proton correlation function is more spread-out in azimuth than for lighter ones, and this effect is more pronounced in the πp channel than in earlier ππ studies. The proton-to-pion yield ratio likewise rises with nuclear mass, although the increase appears to saturate for the heaviest targets. These trends are qualitatively reproduced by state-of-the-art eA event generators, including BeAGLE, eHIJING, and GiBUU, indicating that current descriptions of target fragmentation rest on sound theoretical footing. At the same time, the precision of our data exposes model-dependent discrepancies, delineating a clear path for future improvements in the treatment of cold-nuclear matter effects in eA scattering.
Rights
© 2026 The Authors
This is an open access article under the Creative Commons Attribution 4.0 International (CC BY 4.0) License.
Data Availability
Article states: "We provide in Ref. [48] the code we used to extract the (Δϕ, ΔY) histograms from the output files of event generators (in order to produce the correlation functions) in the form of a module in the Rivet framework [49]. The values of the correlation functions, the ratio R, RMS widths, and broadenings reported in this work can be found in the Supplementary Materials [31]. Data will be made available on request.
Original Publication Citation
Paul, S. J., Arratia, M., Hakobyan, H., Brooks, W., Acar, A., Achenbach, P., Alvarado, J. S., Armstrong, W. R., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bossù, F., Boiarinov, S., Brinkmann, K. T., Briscoe, W. J.,…Zurek, M. (2026). First study of the nuclear response to fast hadrons via angular correlations between pions and slow protons in electron-nucleus scattering. Physics Letters B, 874, Article 140250. https://doi.org/10.1016/j.physletb.2026.140250
ORCID
0009-0009-3736-5832 (Fogler), 0000-0003-2086-2807 (Hattawy), 0009-0003-7645-1289 (Tenorio)
Repository Citation
The CLAS Collaboration; Paul, S. J.; Arratia, M.; Hakobyan, H.; Brooks, W.; Acar, A.; Achenbach, P.; Alvarado, J. S.; Armstrong, W. R.; Baltzell, N. A.; Barion, L.; Bashkanov, M.; Battaglieri, M.; Benmokhtar, F.; Bianconi, A.; Biselli, A. S.; Bossù, F.; Boiarinov, S.; Brinkmann, K. -T; Briscoe, W. J.; Burkert, V.; Cao, T.; Carman, D. S.; Chatagnon, P.; Chinchay, H.; Ciullo, G.; Cole, P. L.; D'Angelo, A.; Dashyan, N.; De Vita, R.; Deur, A.; Diehl, S.; Djalali, C.; Dupre, R.; Egiyan, H.; Alaoui, A. El; Elouadrhiri, L.; Eugenio, P.; Farooq, M.; Fegan, S.; Filippi, A.; Fogler, C.; Gavalian, G.; Gilfoyle, G. P.; Gothe, R. W.; Gualtieri, B.; Hattawy, M.; Hauenstein, F.; Hayward, T. B.; Hoballah, M.; Holtrop, M.; Hung, Yu-Chun; Ilieva, Y.; Ireland, D. G.; Isupov, E. L.; Jenkins, D.; Jo, H. S.; Keller, D.; Khandaker, M.; Kim, A.; Klimenko, V.; Korover, I.; Kripko, A.; Kubarovsky, V.; Lanza, L.; Lee, S.; Lenisa, P.; Li, X.; Marchand, D.; Mascagna, V.; McKinnon, B.; Mineeva, T.; Mokeev, V.; Molina Cardenas, E. F.; Munoz Camacho, C.; Nadel-Turonski, P.; Nagorna, T.; Neupane, K.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Ouillon, M.; Pandey, P.; Paolone, M.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Ouillon, M.; Pandey, P.; Paolone, M.; Pappalardo, L. L.; Paremuzyan, R.; Pasyuk, E.; Paudel, C.; Phelps, W.; Pilleux, N.; Rafael, S. Polcher; Polizzi, L.; Price, J. W.; Prok, Y.; Radic, A.; Reed, T.; Richards, J.; Ripani, M.; Ritman, J.; Rosner, G.; Schadmand, S.; Schmidt, A.; Richards, J.; Ripani, M.; Ritman, J.; Rosner, G.; Schadmand, S.; Schmidt, A.; Schumacher, R. A.; Sharabian, Y.; Shrestha, S.; Sidoretti, E.; Sokhan, D.; Sparveris, N.; Spreafico, M.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Tenorio, M.; Touchte Codjo, F.; Tyson, R.; Ungaro, M.; Vaishnavi, P.S. H.; Vallarino, S.; Velasquez, C.; Venturelli, L.; Voskanyan, H.; Voutier, E.; Wang, Y.; Watts, D. P.; Weerasinghe, U.; Wei, X.; Wood, M. H.; Xu, L.; Xu, Z.; and Zurek, M., "First Study of the Nuclear Response to Fast Hadrons Via Angular Correlations Between Pions and Slow Protons in Electron-Nucleus Scattering" (2026). Physics Faculty Publications. 1037.
https://digitalcommons.odu.edu/physics_fac_pubs/1037
Supplementary Materials