Eur. Phys. J. A (2020) 56: 185
https://doi.org/10.1140/epja/s10050-020-00195-9

Regular Article – Experimental Physics

The FAMU experiment: muonic hydrogen high precision spectroscopy studies

¹ Sezione INFN di Trieste, via A. Valerio 2, Trieste, Italy
² Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31342, Kraków, Poland
³ Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, blvd. Tsarigradsko ch. 72, 1784, Sofia, Bulgaria
⁴ Sezione INFN di Bologna, viale Berti Pichat 6/2, Bologna, Italy
⁵ Dipartimento di Scienze Matematiche, Informatiche e Fisiche, Università di Udine, via delle Scienze 206, Udine, Italy
⁶ Sezione INFN di Milano Bicocca, Piazza della Scienza 3, Milan, Italy
⁷ Dipartimento di Scienze dell’Ambiente e della Terra, Università di Milano Bicocca, Piazza della Scienza 1, Milan, Italy
⁸ Dipartimento di Fisica G. Occhialini, Università di Milano Bicocca, Piazza della Scienza 3, Milan, Italy
⁹ Sezione INFN di Roma Tre, Via della Vasca Navale 84, Rome, Italy
¹⁰ Dipartimento di Ingegneria, Università degli Studi Roma Tre, Via V. Volterra 62, Rome, Italy
¹¹ Sincrotrone Elettra Trieste, SS14, km 163.5, Basovizza, Italy
¹² Dipartimento di Fisica, Università di Pavia, via A. Bassi 6, Pavia, Italy
¹³ Sezione INFN di Pavia, Via A. Bassi 6, Pavia, Italy
¹⁴ Dipartimento di Matematica e Fisica, Università di Roma Tre, Via della Vasca Navale 84, Rome, Italy
¹⁵ Sezione INFN di Napoli e Dipartimento di Matematica e Fisica, Università della Campania “Luigi Vanvitelli”, Viale Lincoln 5, Caserta, Italy
¹⁶ INAF-OAS Bologna, via P. Gobetti 93/3, Bologna, Italy
¹⁷ The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, Trieste, Italy
¹⁸ Laboratoire de Physique des Composants à Semi-conducteurs (LPCS), Départment de physique, Université de Lomé, Lomé, Togo
¹⁹ Gran Sasso Science Institute, via F. Crispi 7, L’Aquila, Italy
²⁰ ISIS Neutron and Muon Source, STFC Rutherford-Appleton Laboratory, Didcot, OX11 0QX, UK
²¹ Riken Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
²² INO-CNR, via Madonna del Piano 10, 50019, Sesto Fiorentino, Italy
²³ IFAC-CNR, via Madonna del Piano 10, 50019, Sesto Fiorentino, Italy
²⁴ Sezione INFN di Milano, via Celoria 16, Milan, Italy
²⁵ Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, Milan, Italy
²⁶ IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, Milan, Italy
²⁷ Indian Centre for Space Physics, Kolkata, India
²⁸ Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People’s Republic of China

^* e-mail: cecilia.pizzolotto@ts.infn.it

Received: 21 January 2020
Accepted: 7 July 2020
Published online: 20 July 2020

Abstract

The FAMU experiment aims to measure for the first time the hyperfine splitting of the muonic hydrogen ground state. From this measurement the proton Zemach radius can be derived and this will shed light on the determination of the proton charge radius. In this paper, we describe the scientific goal, the method and the detailed preparatory work. This includes the outcome of preliminary measurements, subsequent refined simulations and the evaluation of the expected results. The experimental setup being built for the measurement of the hyperfine splitting to be performed at the RAL laboratory muon facility is also described.