First operation of the FAMU experiment at the RIKEN-RAL high intensity muon beam facility
Year: 2025
Authors: Adamczak A., Bakalov D., Baldazzi G., Baruzzo M., Benocci R., Bertoni R., Bonesini M., Capra S., Cirrincione D., Clemenza M., Colace L., Danailov M., Danev P., de Bari A., De Vecchi C., Di Ferdinando D., Fasci E., Gaigher R., Gianfrani L., Hillier AD., Ishida K., Lord JS., Menegolli A., Mocchiutti E., Monzani S., Moretti L., Morgante G., Pizzolotto C., Pullia A., Pullia M., Ramponi R., Roman HE., Rossella M., Rossini R., Sbrizzi A., Stoilov M., Subrez-Vargas JJ., Toci G., Tortora L., Vallazza E., Yokoyama K., Vacchi A.
Autors Affiliation: Polish Acad Sci, Inst Nucl Phys, Radzikowskiego 152, PL-31342 Krakow, Poland; Bulgarian Acad Sci, Inst Nucl Res & Nucl Energy, Blvd Tsarigradsko Ch 72, Sofia 1142, Bulgaria; Univ Bologna, Dipartimento Fis & Astron A Righi, viale Berti Pichat 6-2, Bologna, Italy; Sez INFN Bologna, viale Berti Pichat 6-2, Bologna, Italy; Sez INFN Trieste, via A Valerio 2, Trieste, Italy; Sez INFN Milano Bicocca, Piazza Sci 3, Milan, Italy; Univ Milano Bicocca, Dipartimento Sci Ambiente & Terra, Piazza Sci 1, Milan, Italy; Univ Milano Bicocca, Dipartimento Fis G Occhialini, Piazza Sci 3, Milan, Italy; INFN Sez Milano, Via Celoria 16, Milan, Italy; Univ Milan, Dipartimento Fis, Via Celoria 16, Milan, Italy; Sez INFN Roma Tre, Via Vasca Navale 84, Rome, Italy; Univ Roma Tre, Dipartimento Ingn, Via V Volterra 62, Rome, Italy; Sincrotrone Elettra Trieste, SS14,km 163-5, Basovizza, Italy; Univ Pavia, Dipartimento Fis A Volta, Via A Bassi 6, Pavia, Italy; Sez INFN Pavia, Via A Bassi 6, Pavia, Italy; Sez INFN Napoli, Via Vicinale Cupa Cintia 26, Naples, Italy; Univ Campania, Dipartimento Matemat & Fis L Vanvitelli, Viale Lincoln 5, Caserta, Italy; STFC Rutherford Appleton Lab, ISIS Neutron & Muon Source, Didcot OX11 0QX, England; RIKEN, RIKEN Nishina Ctr, 2-1 Hirosawa, Wako, Saitama 3510198, Japan; Univ Udine, Dipartimento Sci Matemat Informat & Fis, Via Sci 206, I-33100 Udine, Italy; INAF, OAS Bologna, Via P Gobetti 93-3, Bologna, Italy; Ctr Nazl Adroterapia Oncol CNAO, Via Borloni 1, Pavia, Italy; Politecn Milan, IFN CNR, Dipartimento Fis, piazza Leonardo Vinci 32, Milan, Italy; INO CNR, Via Madonna Piano 10, I-50019 Sesto Fiorentino, Italy; INFN LNS, Catania, Italy.
Abstract: The FAMU experiment, supported and funded by the Italian Institute of Nuclear Physics (INFN) and by the Science and Technology Facilities Council (STFC), aims to perform the first measurement of the ground-state hyperfine splitting (1S-hfs) of muonic hydrogen (μH). This quantity is highly sensitive to the proton’s Zemach radius RZ. An experimental determination of RZ provides significant constraints on the parametrisation of the proton form factors as well as on theoretical models describing the proton’s electromagnetic structure. Following years of technological and methodological development, the FAMU experiment began operations in 2023 at Port 1 of the RIKEN-RAL muon beam line at the ISIS Neutron and Muon Source facility (Didcot, UK). In this paper, we first describe the unique detection technique employed by FAMU to determine the 1S-hfs of muonic hydrogen, followed by a detailed presentation of the final experimental layout. Finally, we report the first outcome from the 2023 commissioning run and from the initial physics runs performed in 2023 and 2024.
Journal/Review: EUROPEAN PHYSICAL JOURNAL A
Volume: 61 (12) Pages from: 284-1 to: 284-18
More Information: Open access funding provided by Universita degli Studi di Pavia within the CRUI-CARE Agreement.KeyWords: Proton Structure; Hydrogen; Spectroscopy; ShiftDOI: 10.1140/epja/s10050-025-01758-4
