Improved Λp Elastic Scattering Cross Sections between 0.9 and 2.0 GeV/c as a Main Ingredient of the Neutron Star Equation of State

Rowley, J.; Compton, N.; Djalali, C.; Hicks, K.; Price, J.; Zachariou, N.; Adhikari, K. P.; Armstrong, W. R.; Atac, H.; Baashen, L.; Barion, L.; Bashkanov, M.; Battaglieri, M.; Bedlinskiy, I.; Benmokhtar, F.; Bianconi, A.; Biondo, L.; Biselli, A. S.; Bondi, M.; Bossu, F.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bulumulla, D.; Burkert, V. D.; Carman, D. S.; Carvajal, J. C.; Celentano, A.; Chatagnon, P.; Chesnokov, V.; Chetry, T.; Ciullo, G.; Clark, L.; Cole, P. L.; Contalbrigo, M.; Costantini, G.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; Defurne, M.; Deur, A.; Diehl, S.; Dupre, R.; Egiyan, H.; Ehrhart, M.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Filippi, A.; Fradi, A.; Gavalian, G.; Girod, F. X.; Glazier, D. I.; Golubenko, A.; Gothe, R. W.; Griffioen, K.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hattawy, M.; Hayward, T. B.; Heddle, D.; Hobart, A.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Isupov, E. L.; Jenkins, D.; H. S., Jo; Joo, K.; Keller, D.; Khanal, A.; Khandaker, M.; Kim, A.; Korover, I.; Kripko, A.; Kubarovsky, V.; Kuhn, S. E.; Lanza, L.; Leali, M.; Lenisa, P.; Livingston, K.; Macgregor, I. J. D.; Marchand, D.; Markov, N.; Marsicano, L.; Mascagna, V.; Mccracken, M. E.; Mckinnon, B.; Mclauchlin, C.; Meziani, Z. E.; Migliorati, S.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Neupane, K.; Niccolai, S.; Niculescu, G.; O'Connell, T. R.; Osipenko, M.; Ostrovidov, A. I.; Pandey, P.; Paolone, M.; Pappalardo, L. L.; Pasyuk, E.; Pogorelko, O.; Prok, Y.; Reed, T.; Ripani, M.; Ritman, J.; Rizzo, A.; Rosner, G.; Sabatie, F.; Salgado, C.; Schmidt, A.; Schumacher, R. A.; Sharabian, Y. G.; Shrestha, U.; Sokhan, D.; Soto, O.; Sparveris, N.; Strakovsky, I. I.; Strauch, S.; Tyson, R.; Ungaro, M.; Venturelli, L.; Voskanyan, H.; Vossen, A.; Voutier, E.; Watts, D. P.; Wei, K.; Wei, X.; Wishart, R.; Wood, M. H.; Yale, B.; Yurov, M.; Zhang, J.; Zhao, Z. W.

doi:10.1103/PhysRevLett.127.272303

Strange matter is believed to exist in the cores of neutron stars based on simple kinematics. If this is true, then hyperon-nucleon interactions will play a significant part in the neutron star equation of state. Yet, compared to other elastic scattering processes, there is very little data on Λ-N scattering. This experiment utilized the CEBAF Large Acceptance Spectrometer (CLAS) detector to study the Λp→Λp elastic scattering cross section in the incident Λ momentum range 0.9-2.0 GeV/c. These are the first data on this reaction since the 1970s. The new cross sections have significantly better accuracy and precision than the existing world data, and the techniques developed here can also be used in future experiments.