Johannes Gutenberg University Mainz > Faculty 08 > Physics > Physics Research > Research Areas > Hadron & Nuclear Physics
What is the shape and size of the proton, of other hadrons, and of nuclei? We endeavor to answer these questions using a variety of experimental techniques. They range from form factor measurements in electron scattering using our unique electron accelerators MAMI and MESA via electron-positron collisions to charge radius measurements using muonic atoms. At the same time, we are developing the theoretical methods and performing the calculations needed to correct and interpret these measurements.
How do quarks and gluons combine to form hadrons? What bound systems exist and what are their binding energies and their excitations? We elucidate these questions using electron-positron and proton-antiproton collisions as well as electron and photon scattering experiments. We study the excited states of the nucleon and of unconventional hadrons containing more than three quarks, particularly if one of them is a charm quark.
A detailed understanding of hadrons and nuclei forms the basis of many precision measurements designed to test the Standard Model of elementary particle physics or determine fundamental constants. The P2 experiment at MESA aims to measure the weak mixing angle – a fundamental parameter of the Standard Model – in parity-violating electron-proton scattering, which requires a detailed understanding of the proton. Hadronic contributions lead to the largest uncertainties in predictions of the muon g-factor, one of the most precisely calculated and measured quantities in the Standard Model. We provide experimental, phenomenological and lattice QCD input to quantify these hadronic contributions and shrink their uncertainties, leading to ever more stringent tests of the Standard Model.
We study how stars forge the elements and how matter behaves under extreme conditions, from the nuclear reactions powering stellar evolution to the dense matter inside neutron stars. Find out more about our nuclear astrophysics research in the section “Stellar & Galactic Physics” on our webpage “Astro-, Astroparticle & Neutrinophysics”.
Experimental & Theoretical Research Groups
Neutron physics studies the properties, behavior, and interactions of neutrons, the electrically neutral component of atomic nuclei. We investigate free neutrons with high precision to determine their lifetime, their magnetic interaction, the possible existence of an electric dipole moment and the correlations between the neutron’s decay products. We generate free neutrons either from nuclear fission in nuclear reactors like the TRIGA reactor or from spallation sources like at PSI.
At the scales of interest for hadron and nuclear physics, the strength of the strong interaction does not allow for perturbative expansions. Instead, calculations can be performed using discretized space-time and Monte-Carlo methods on supercomputers. The Mainz lattice group performs pioneering calculations for hadron spectroscopy and structure as well as for hadronic corrections to precision observables, particularly the magnetic moment of the muon.
Flavour physics describes the transitions between different generations (flavours) of quarks and leptons via the weak interaction. To learn more about our research in “Flavour Physics” please visit the webpage “High Energy Particle Physics”.
Experimental & Theoretical Research Groups
