Laser excitation of the 1s-hyperfine transition in muonic hydrogen

Abstract

The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen (µp) with 1 ppm accuracy by means of pulsed laser spectroscopy to determine the two-photon-exchange contribution with 2 × 10 −4 relative accuracy. In the proposed experiment, the µp atom which undergoes a laser excitation from the singlet hyperfine state to the triplet hyperfine state, is quenched back to the singlet state by an inelastic collision with a H 2 molecule. The resulting increase of kinetic energy after the collisional deexcitation is used as a signature of a successful laser transition between hyperfine states. In this paper we calculate the combined probability that a µp atom initially in the singlet hyperfine state undergoes a laser excitation to the triplet state followed by a collisional-induced deexcitation back to the singlet state. This combined probability has been computed using the optical Bloch equations including the inelastic and elastic collisions. Omitting the

Experimental determination of the energy dependence of the rate of the muon transfer reaction from muonic hydrogen to oxygen for collision energies up to 0.1 eV

“…The ground-state hyperfine splitting of pµ, ∆E hfs ∼ 0.182 eV, turns out to be in the infra-red optical range, thus enabling the application of laser spectroscopy techniques. A number of experimental proposals for the measurement of ∆E hfs have been put forward in recent years [42][43][44][45][46][58][59][60].…”

“…The interest in the subject was revived a few years later in relation to the projects to measure the hyperfine splitting in the ground state of muonic hydrogen [42][43][44][45][46], and extract out of it the value of the electromagnetic Zemach radius of the proton [47,48]. In a series of advanced theoretical calculations [24,25,29] significant progress was achieved in the quantitative description of the process (3) for energies up to 10 eV, but these theoretical results necessitate experimental verification.…”

The proton radius and its relatives - much ado about nothing?

“…and m p (m l ) is the proton (lepton) mass. A precise evaluation of ∆ µH recoil is timely given the ongoing experimental efforts carried out by three collaborations that aim at the HFS in µH [50,51,52] with relative accuracies ranging from 1 to 10 ppm.…”

Muonic vs electronic dark forces: a complete EFT treatment for atomic spectroscopy

“…We consider also the projection for realistic improvements on the uncertainty of each system. All the hyperfine experimental measurements considered here have the common characteristic that the experimental uncertainty is larger than the theoretical one, thus, as a future projection, we consider that the experimental precision could reach the theoretical one in upcoming experiments such as the ones proposed by the CREMA collaboration [49] or FAMU [50]. We do not include the muonic deuterium 2s hyperfine measurement due to the recently found tension between the experimental and theoretical determinations [51].…”