Jun 5 – 9, 2023
Genova, Italy
Europe/Rome timezone

High-resolution hypernuclear decay pion spectroscopy at MAMI and future

Jun 8, 2023, 2:56 PM
DAD - Room 1A (Genova, Italy)

DAD - Room 1A

Genova, Italy

Invited Hypernuclei and kaonic atoms Hypernuclei and kaonic atoms


Prof. Sho Nagao (The University of Tokyo)


Precise measurements of $\Lambda$ hypernuclear binding energies are essential in understanding the interaction between $\Lambda$ and nucleons. Thanks to the recent progress of accurate theoretical calculations and cutting-edge experiments for $\Lambda$ hypernuclei around the light mass regions, the studies of the interaction of the hypernuclear medium have progressed well; for example, the effect of $\Lambda$-$\Sigma$ coupling and the $\Lambda$-N Charge Symmetry Breaking. Though recent $^3_\Lambda$H mass and lifetime results from the heavy-ion collision experiments have significantly impacted reconsidering the hypernuclear picture, more accurate measurements are necessary to discuss further.
We have developed a new technique "decay pion spectroscopy" to measure the $\Lambda$ binding energies of the hypernuclear ground states with an accuracy of better than 100 keV/$c^2$. In 2015, we successfully measured the $\Lambda$ binding energy of $^4_\Lambda$H by measuring the momentum of two-body decay pion from $^4_\Lambda$H with a resolution of $<$100 keV/$c$ in FWHM.
We applied the same spectroscopic technique to $^3_\Lambda$H by updating the target system and the energy calibration method. The physics data taking was already done in 2022, and the analysis is ongoing.
I will present the updated experiment and the latest analysis status. I will also introduce a plan for high-resolution spectroscopy of $\Lambda$ hypernuclei.

Primary author

Prof. Sho Nagao (The University of Tokyo)


Dr Anselm Esser (Johannes Gutenberg University Mainz) Dr Björn Sören Schlimme (Johannes Gutenberg University Mainz) Mr Christian Helmel (Johannes Gutenberg University Mainz) Prof. Concettina Sfienti (Johannes Gutenberg University Mainz) Prof. Harald Merkel (Johannes Gutenberg University Mainz) Jan Bernauer (Stony Brook University) Prof. Josef Pochodzalla (Johannes Gutenberg University Mainz) Mr Julian Geratz (Johannes Gutenberg University Mainz) Mr Kazuki Okuyama (Tohoku University) Mr Ken Nishida (The University of Tokyo) Mr Koga Tachibana (Tohoku University) Mr Kotaro Nishi (The University of Tokyo) Prof. Liguang Tang (Hampton University/Jefferson Lab) Luca Doria (Johannes Gutenberg University Mainz) Dr Marcell Steinen (Johannes Gutenberg University Mainz) Dr Masashi Kaneta (Tohoku University) Mr Masaya Mizuno (Tohoku University) Mr Michael Hoek (Johannes Gutenberg University Mainz) Dr Michael O. Distler (Johannes Gutenberg University Mainz) Ms Michaela Thiel (Johannes Gutenberg University Mainz) Mr Pascal Klag (Johannes Gutenberg University Mainz) Patrick Achenbach (Jefferson Lab) Philipp Eckert (Johannes Gutenberg University Mainz) Dr Ralph Böhm (FAIR) Ms Ryoko Kino (Tohoku University) Prof. Satoshi N. Nakamura (the University of Tokyo) Mr Takeru Akiyama (Tohoku University) Mr Tatsuhiro Ishige (Tohoku University) Mr Tianhao Shao (Johannes Gutenberg University Mainz) Mr Ulrich Müller (Johannes Gutenberg University Mainz) Dr Werner Lauth (Johannes Gutenberg University Mainz) Dr Yuichi Toyama (Chubu Univeristy)

Presentation materials