Measuring the muonic H ground state hyperfine splitting with FAMU

The FAMU experiment will measure the hyperfine splitting in the ground state of muonic hydrogen \u394Ehfs(\u3bc 12 p)1s with a precision \u3b4\u3bb/\u3bb < 10 125 providing rZ, the Zemach radius of the proton with higher precision, than what was previously possible, disentangling discordant theoretical values. The aim is to set a cornerstone result about not yet explained anomalies on the charge radius rch of the proton. The Zemach radius rZ and the charge radius rch are the only proton shape-related values that can be directly extracted from experimental data, and rZ is the only one that gives information about the proton\u2019s magnetic dipole moment distribution. The status of the experiment is presented

FAMU: study of the energy dependent transfer rate \u39b \u3bcp \u2192 \u3bcO

The main goal of the FAMU experiment is the measurement of the hyperfine splitting (hfs) in the 1S state of muonic hydrogen \u394Ehfs (\u3bc - p)1S. The physical process behind this experiment is the following: \u3bcp are formed in a mixture of hydrogen and a higher-Z gas. When absorbing a photon at resonance-energy \u394Ehfs 48 0.182 eV, in subsequent collisions with the surrounding H 2 molecules, the \u3bcp is quickly de-excited and accelerated by ~ 2/3 of the excitation energy. The observable is the time distribution of the K-lines X-rays emitted from the \u3bcZ formed by muon transfer (\u3bcp) + Z \u2192 (\u3bcZ)* + p, a reaction whose rate depends on the \u3bcp kinetic energy. The maximal response, to the tuned laser wavelength, of the time distribution of X-ray from K-lines of the (\u3bcZ)* cascade indicate the resonance. During the preparatory phase of the FAMU experiment, several measurements have been performed both to validate the methodology and to prepare the best configuration of target and detectors for the spectroscopic measurement. We present here the crucial study of the energy dependence of the transfer rate from muonic hydrogen to oxygen (\u39b \u3bcp \u2192 \u3bc0 ), precisely measured for the first time