HFS-CREMA: Laser spectroscopy of the muonic hydrogen hyperfine splitting by the CREMA collaboration

Project funded by Fundação para a Ciência e a Tecnologia, I.P. (FCT) (Concurso para Financiamento de Projetos de Investigação Científica e Desenvolvimento Tecnológico em Todos os Domínios Ci), grant PTDC/FIS-AQM/29611/2017. Funded amount: EUR 230,621, as stated by the source. Runs 2018-10-01 to 2022-01-31. Keywords: Hyperfine splitting, Muonic hydrogen, Laser spectroscopy, Quantum Electrodynamics, Exact sciences. Source: OpenAIRE Graph, from the funder's project data (collected by OpenAIRE on 2026-07-23); national funding data, not CORDIS; selected because its keywords name quantum. Abstract given by the source: The international collaboration CREMA has completed several laser spectroscopy experiments of different muonic atoms, where several transition frequencies between 2S and 2P states (the so-called Lamb shift) were measured in muonic hydrogen and muonic deuterium atoms, as well as in muonic helium ions. As a result of the mass difference between a muon and an electron, there is a strong overlap between the muon and nucleus wave functions, making laser spectroscopy of muonic atoms a unique technique to obtain important information about the nuclear structure (e.g. the nucleus charge and magnetic moment distributions), since the technique allows high-precision measurements of transition frequencies in muonic atoms. Transitions measured by the collaboration in the preceding experiments made possible to obtain estimates for the nuclear charge radius of hydrogen, deuterium and helium ions (He-3 and He-4). The new experiment proposed by the CREMA collaboration to PSI (Paul Scherrer Institute) consists on the measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen, the muonic helium HFS to be measured afterwards. The measurement of the 1S-HFS frequency involves the transition from the singlet to the triplet sublevels of the ground state, and will allow to estimate the Zemach radius, a convolution between the proton charge and magnetic moment distributions. The experiment will allow a better understanding of the proton structure by combining results from charge and magnetic moment distributions obtained from the measurement of different transition frequencies in muonic hydrogen. The HFS transition will be induced by a laser. In the subsequent de-excitation of the triplet sublevels, part of the energy is transferred to muonic hydrogen atoms, which may diffuse to the detector walls, coated with a material of high atomic number Z, producing high-Z muonic atoms in excited states, which promptly decay to the ground state emitting x-rays. The kinetic energy [shortened; the full text is on the OpenAIRE page]

Original source.

Source: OpenAIRE Graph: projects of national funders, OpenAIRE, from the project data of Fundação para a Ciência e a Tecnologia, I.P. (FCT). Retrieved 2026-10-28. Licence: Creative Commons Attribution 4.0 (OpenAIRE Graph). Selected metadata, adapted presentation; the publisher's record is authoritative. No endorsement by the source is implied. Licence: Creative Commons Attribution 4.0 (CC BY 4.0).

AI-assisted summary: The HFS-CREMA project, funded by FCT with EUR 230,621, ran from October 1, 2018, to January 31, 2022. It involved laser spectroscopy experiments on muonic hydrogen and other muonic atoms to study hyperfine splitting and nuclear structure. Suggested technology pillar: sensing. Generated by AI from the public source text; it may contain errors and the original source is authoritative.