Related papers: The neutron-proton mass difference
Nucleon-nucleon systems are studied with lattice quantum chromodynamics at a pion mass of $m_\pi\sim 450~{\rm MeV}$ in three spatial volumes using $n_f=2+1$ flavors of light quarks. At the quark masses employed in this work, the deuteron…
We present the first lattice-QCD result for the Zemach and Friar radii of the proton and neutron. Our calculation includes both quark-connected and -disconnected diagrams and assesses all sources of systematic uncertainties arising from…
We construct a model that allows us to determine the three neutrino masses directly from the experimental mass squared differences, $\Delta_{\rm atm}$ and $\Delta_{\rm sol}$, together with the assumption that $\Lambda = \surd (1/6) = \surd…
The mass structure of hadron multiplets is understood to imply the inexactness of SU(3) symmetry. Here we show that these symmetry broken mass splittings amongst baryon and meson multiplet members are close integral multiples of the mass…
During the runs of the PS 179 experiment at LEAR of CERN, we photographed an event of antiproton-Ne absorption, with a complete pi+ -> mu+ ->e+ chain. From the vertex of the reaction a very slow energy pi+ was emitted. The pi+ decays into a…
Using an approach free from momentum extrapolation, we calculate the nucleon magnetic moment and the fraction of the nucleon spin carried by the quark angular momentum in the quenched lattice QCD approximation. Quarks with three values of…
After a short review of Lattice QCD methodology and techniques, I summarize recent results of Lattice QCD calculations of the interactions of nucleons and light nuclei with magnetic fields at pion masses of 805 MeV and 450 MeV.…
Results on the electromagnetic form factors of the nucleon using twisted mass fermion configurations are presented. These include a gauge field ensemble simulated with two degenerate light quarks yielding a pion mass of around 130 MeV, as…
The proton mass calculation is still a tough challenge for lattice QCD. We discuss the current status and difficulties based on the recent PACS-CS results for the hadron spectrum in 2+1 flavor QCD.
The neutron-proton effective mass splitting ($\Delta m^*_{np}$) is investigated through analyses of heavy-ion collisions using the improved quantum molecular dynamics (ImQMD) model with both standard and extended Skyrme interactions. By…
We present recent results on the first moments of parton distributions using gauge configurations generated with two degenerate flavors of light twisted mass quarks with pion mass fixed approximately to its physical value. We also present a…
If three right-handed neutrinos are added to the Standard Model, then, for the three known generations, there are six quarks and six leptons. It is then natural to assume that the symmetry considerations that have been applied to the quark…
In this work, we used a $32^3 \times 64 \times 32$, 2+1 flavor domain wall lattice with Iwasaki+DSDR gauge action. The pion mass is 171 MeV and the kaon mass is 492 MeV. We implement the Glashow-Iliopoulos-Maiani (GIM) cancellation using…
The finite temperature and finite density dependence of the neutron-proton mass difference is analysed in a purely hadronic framework where the $\rho-\omega $ mixing is crucial for this isospin symmetry breakdown. The problem is handled…
We compute the electromagnetic form factors of the proton and neutron using lattice QCD. We employ $N_\mathrm{f}$=2+1+1 twisted mass clover-improved fermions with quark masses tuned to their physical values. Three ensembles with lattice…
There is a long-standing discrepancy between different measurements of the electric and magnetic radii of the proton. Lattice QCD calculations are a well-suited tool for theoretical investigations of the structure of the nucleon from first…
We calculate potentials between a proton and a $\Xi^0$ (hyperon with strangeness -2) through the equal-time Bethe-Salpeter wave function, employing quenched lattice QCD simulations with the plaquette gauge action and the Wilson quark action…
We present lattice QCD calculations of nucleon electromagnetic form factors using pion masses $m_\pi$ = 149, 202, and 254 MeV and an action with clover-improved Wilson quarks coupled to smeared gauge fields, as used by the…
We propose a precision measurement of time variations of the proton-electron mass ratio using ultracold molecules in an optical lattice. Vibrational energy intervals are sensitive to changes of the mass ratio. In contrast to measurements…
The proton is a fundamental constituent of matter. It is an extended object with finite size that can be inferred with some degree of accuracy from several measurements. Using constraints from the analytic behavior of the form factors we…