Related papers: Two-photon exchange correction to the hyperfine sp…
We review the role of two-photon exchange (TPE) in electron-hadron scattering, focusing in particular on hadronic frameworks suitable for describing the low and moderate Q^2 region relevant to most experimental studies. We discuss the…
The two-photon-exchange (TPE) contribution in $ep\rightarrow ep\pi ^0$ with $W=M_{\Delta}$ and small $Q^2$ is calculated and its corrections to the ratios of electromagnetic transition form factors $R_{EM} = E_{1+}^{(3/2)}/M_{1+}^{(3/2)} $…
We calculate the two-photon exchange correction to the Lamb shift in muonic helium-3 ions within the dispersion relations framework. Part of the effort entailed making analytic fits to the electron-$^3$He quasielastic scattering data set,…
We present new precision measurements of the elastic electron-proton scattering cross section for momentum transfer (Q$^2$) up to 15.75~\gevsq. Combined with existing data, these provide an improved extraction of the proton magnetic form…
Corrections of orders alpha^5 and alpha^6 are calculated in the hyperfine splittings of 1S and 2S - energy levels in the ion of muonic helium. The electron vacuum polarization effects, the nuclear structure corrections and recoil…
Leading electroweak corrections play an important role in precision measurements of the strange form factors. We calculate the two-photon-exchange (TPE) and $\gamma Z$-exchange corrections to the parity-violating asymmetry of the elastic…
We present an exact analytical evaluation of the two-photon exchange (TPE) correction to the elastic lepton-proton differential scattering cross section at low-energies within the framework of heavy-baryon chiral perturbation theory. Our…
We evaluate the two-photon exchange (TPE) correction to the unpolarized elastic electron-proton scattering at small momentum transfer $ Q^2 $. We account for the inelastic intermediate states approximating the double virtual Compton…
The largest uncertainty in calculations of hydrogen ground-state hyperfine splitting comes from corrections due to proton stucture. We review these corrections, with special mention of the inelastic, or polarizability, corrections which…
The goal of the FAMU experiment at RIKEN RAL is the measure of the hyperfine splitting of the ground state of the muonic hydrogen, to allow a determination of the proton Zemach radius with a precision better than $5 \times 10^{-3}$ . The…
Two-photon exchange (TPE) is one of the leading explanations for discrepancies in measurements of the proton electromagnetic form factors. It has been proposed that TPE could impact not only elastic scattering, but also the cross sections…
One possible explanation for the proton form factor discrepancy is a contribution to the elastic electron-proton cross section from hard two-photon exchange (TPE), a typically neglected radiative correction. Hard TPE cannot be calculated in…
Precision spectroscopy of hyperfine splitting (HFS) is a crucial tool for investigating the structure of nuclei and testing quantum electrodynamics (QED). However, accurate theoretical predictions are hindered by two-photon exchange (TPE)…
The proton elastic form factor ratio shows a discrepancy between measurements using the Rosenbluth technique in unpolarized beam and target experiments and measurements using polarization degrees of freedom. The proposed explanation of this…
Radiative-recoil corrections to hyperfine splitting in muonium of orders $\alpha(Z\alpha)(m/M)^2E_F$ and $(Z^2\alpha)(Z\alpha)(m/M)^2E_F$ are calculated. These corrections are of the second order in the small electron-muon mass ratio. An…
Predictions for the two-photon exchange (TPE) correction to unpolarized $ep$ elastic cross section, obtained within two different approaches, are confronted and discussed in detail. In the first one the TPE correction is extracted from…
We calculate two-photon exchange (TPE) amplitudes for the elastic electron-proton scattering, and take into account intermediate hadronic states containing \pi N system with total angular momentum 1/2 or 3/2, which includes 8 different…
Two-photon exchange contributions to elastic electron-scattering are reviewed. The apparent discrepancy in the extraction of elastic nucleon form factors between unpolarized Rosenbluth and polarization transfer experiments is discussed, as…
The hyperfine splitting in hydrogenlike $^{209}$Bi, $^{203}$Tl, and $^{205}$Tl is calculated with the nuclear magnetization determined from experimental data on the hyperfine splitting in the corresponding muonic atoms. The single-particle…
Corrections of orders alpha^5, alpha^6 are calculated in the hyperfine splitting of the 2S state in the muonic hydrogen. The nuclear structure effects are taken into account in the one- and two-loop Feynman amplitudes by means of the proton…