Related papers: Single-nucleon experiments
Single pion production off nucleons is studied in the framework of heavy baryon chiral perturbation theory to third order in the chiral expansion. Using total and some older differential cross section data to pin down the low-energy…
The five low-energy constants (LECs) in the electromagnetic current derived in chiral effective field theory ($\chi$EFT) up to one loop are determined by a simultaneous fit to the $A\,$=$\,2$--3 nuclei magnetic moments and to the deuteron…
The value of the pion polarizability is predicted with high precision by Chiral Perturbation Theory. However, the existing experimental values are at tension with this prediction as well as among themselves. The COMPASS experiment at the…
In this sketch, I focus on Physics and formalism behind dynamical polarisabilities, a new tool to test and interpret quantitative predictions about the low-energy degrees of freedom inside the nucleon from the multipoles of Compton…
In the framework of chiral effective field theory of delta resonances, nucleons and pions interacting with background gravitational field we calculate the gravitational form factors of the nucleon up to fourth order in the small scale…
Measuring the spin structure of protons and neutrons tests our understanding of how they arise from quarks and gluons, the fundamental building blocks of nuclear matter. At long distances the coupling constant of the strong interaction…
In the modern description of nuclear forces based on chiral effective field theory, four-nucleon operators with unknown coupling constants appear. These couplings can be fixed by a fit to the low partial waves of neutron-proton scattering.…
I discuss recent results on the electroproduction and photoproduction of mesons in the region of non-strange baryon resonances. Results on the quadrupole transition from the ground state nucleon to the Delta(1232) show the importance of…
We report results for the virtual photon asymmetry $A_1$ on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton ($^{15}$NH$_3$) and deuteron…
Three instances are discussed in which results produced by chiral perturbation theory can be reliably pushed to high space-like values of transferred momenta: 1. nuclear interactions, 2. nucleon sigma-term and 3. space-like structure of the…
We study the incoherent neutrinoproduction of photons and pions with neutrino energy E_{\nu} $\leqslant$ 0.5 GeV. These processes are relevant to the background analysis in neutrino-oscillation experiments, for example MiniBooNE [A. A.…
The values of charged pion polarizabilities obtained in the framework of chiral perturbation theory at the level of two-loop accuracy are compared with the experimental result recently reported by COMPASS Collaboration. It is found that the…
Recent progress from Jefferson Lab has significantly improved our understanding of the nucleon spin structure in the high-$x$ region. Results from two experiments in Hall A are presented. The first experiment is a precision measurement of…
The Chiral Perturbation Theory (CHPT) has been very successful in describing low-energy hadronic properties in the non-perturbative regime of Quantum Chromodynamics. The results of ChPT, many of which are currently under active experimental…
Experimental form factors of the hydrogen and helium isotopes, extracted from an up-to-date global analysis of cross sections and polarization observables measured in elastic electron scattering from these systems, are compared to…
Two groups, ours (Mainz) and Bochum, have recently been re-evaluating the spin polarizabilities and spin structure functions at low $Q$, using the baryon chiral perturbation theory (B$\chi$PT), the manifestly-covariant counterpart of the…
Low-energy Compton scattering off the proton is used for determination of the proton polarizabilities. However, the present empirical determinations rely heavily on the theoretical description(s) of the experimental cross sections in terms…
We have studied charged current one pion production induced by $\nu_\mu(\bar\nu_\mu)$ from some nuclei. The calculations have been done for the incoherent pion production processes from these nuclear targets in the $\Delta$ dominance model…
As increased statistics and new ensembles with light pions have become available within the CLS effort, we complete previous work by inspecting the chiral behaviour of the pion decay constant. We discuss the validity of Chiral Perturbation…
The ratio of electric to magnetic proton form factors G_E/G_M as measured in polarization transfer experiments shows a characteristic linear decrease with increasing momentum transfer Q^2. We present a simple argument how such a decrease…