iTHEMS-RNC Meson Science Lab. Joint Seminar

Study of the eta' meson in nuclei in the LEPS2/BGOegg experiment

August 26 (Fri) at 16:30 - 18:00, 2022

Dr. Natsuki Tomida (Specially Appointed Assistant Professor, Center for Science Adventure and Collaborative Research Advancement (SACRA), Graduate School of Science, Kyoto University)

A large mass reduction of eta'(958) meson in nuclear medium owing to its UA(1) anomaly is expected in several model calculations. We carried out the LEPS2/BGOegg experiment at SPring-8 to study eta' meson properties in nuclei. If there is a large mass reduction in nuclei, an eta' meson and a nucleus may form a bound state. We searched for the eta'-nucleus bound states via missing mass spectroscopy of the 12C(gamma, p) reaction. To suppress background events from multi-meson production, we simultaneously measured decay products from the eta'-nucleus system for the first time. We also carried out the missing mass spectroscopy simultaneously detecting an eta' meson escaping from a nucleus for the first time. We will show the experimental results and comparisons with theoretical calculations. We will also show the preliminary results of the line shape analysis of the invariant mass spectra of the eta'->2gamma decay in the gamma+12C->eta'+X reaction.

Venue: Common Room #246-248 (Main Venue) / via Zoom

Event Official Language: English