First Study of the Nuclear Response to Fast Hadrons via Angular Correlations between Pions and Slow Protons in Electron-Nucleus Scattering
Abstract
We report on the first measurement of angular correlations between high-energy pions and slow protons in electron-nucleus () 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 channel than in earlier 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 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 scattering.
Keywords
Cite
@article{arxiv.2512.05083,
title = {First Study of the Nuclear Response to Fast Hadrons via Angular Correlations between Pions and Slow Protons in Electron-Nucleus Scattering},
author = {S. J. Paul and M. Arratia and H. Hakobyan and W. Brooks and A. Acar and P. Achenbach and J. S. Alvarado and W. R. Armstrong and N. A. Baltzell and L. Barion and M. Bashkanov and M. Battaglieri and F. Benmokhtar and A. Bianconi and A. S. Biselli and F. Bossù and S. Boiarinov and K. -T. Brinkmann and W. J. Briscoe and V. Burkert and T. Cao and D. S. Carman and P. Chatagnon and H. Chinchay and G. Ciullo and P. L. Cole and A. D'Angelo and N. Dashyan and R. De Vita and A. Deur and S. Diehl and C. Djalali and R. Dupre and H. Egiyan and A. El Alaoui and L. Elouadrhiri and P. Eugenio and M. Farooq and S. Fegan and A. Filippi and C. Fogler and G. Gavalian and G. P. Gilfoyle and R. W. Gothe and B. Gualtieri and M. Hattawy and F. Hauenstein and T. B. Hayward and M. Hoballah and M. Holtrop and Yu-Chun Hung and Y. Ilieva and D. G. Ireland and E. L. Isupov and D. Jenkins and H. S. Jo and D. Keller and M. Khandaker and A. Kim and V. Klimenko and I. Korover and A. Kripko and V. Kubarovsky and L. Lanza and S. Lee and P. Lenisa and X. Li and D. Marchand and V. Mascagna and B. McKinnon and T. Mineeva and V. Mokeev and E. F. Molina Cardenas and C. Munoz Camacho and P. Nadel-Turonski and T. Nagorna and K. Neupane and S. Niccolai and G. Niculescu and M. Osipenko and A. I. Ostrovidov and M. Ouillon and P. Pandey and M. Paolone and L. L. Pappalardo and R. Paremuzyan and E. Pasyuk and C. Paudel and W. Phelps and N. Pilleux and P. S. H. Vaishnavi and S. Polcher Rafael and L. Polizzi and J. W. Price and Y. Prok and A. Radic and T. Reed and J. Richards and M. Ripani and J. Ritman and G. Rosner and S. Schadmand and A. Schmidt and R. A. Schumacher and Y. Sharabian and S. Shrestha and E. Sidoretti and D. Sokhan and N. Sparveris and M. Spreafico and S. Stepanyan and I. I. Strakovsky and S. Strauch and M. Tenorio and F. Touchte Codjo and R. Tyson and M. Ungaro and S. Vallarino and C. Velasquez and L. Venturelli and H. Voskanyan and E. Voutier and Y. Wang and D. P. Watts and U. Weerasinghe and X. Wei and M. H. Wood and L. Xu and Z. Xu and M. Zurek},
journal= {arXiv preprint arXiv:2512.05083},
year = {2026}
}