Narrow Results

We report an experimental determination of the isospin of ${\mathrm{\Lambda }}_c/{\mathrm{\Sigma }}_c{\left(2765\right)}^{+}$ using 980 fb⁻¹ data in the e⁺e⁻ annihilation around $\sqrt{s}=10.6\text{GeV}$ collected by the Belle detector located at the KEKB collider. The isospin partners are searched for in the ${\mathrm{\Sigma }}_c{\left(2455\right)}^{++/0}{\pi }^0$ channels, and no evidence was obtained. Thus the isospin is determined to be zero, and the particle is established to be a Λ_c.

In this paper we present a study of the nucleon-pair approximation with the isospin symmetry. In this model the building blocks are collective nucleon-pairs with given spin and isospin. We exemplify our work by using the ⁹⁶Cd nucleus.

Recent work unambiguously resolves the level of charge symmetry violation in moments of parton distributions using (2+1)-flavor lattice QCD. We introduce the methods used for that analysis by applying them to determine the strong contribution to the proton–neutron mass difference. We also summarize related work which reveals that the fraction of baryon spin which is carried by the quarks is in fact structure-dependent rather than universal across the baryon octet.