arXiv subjects
Publications and source records attributed to K. Kimura.
A level-one representation of the quantum affine superalgebra $\U_q(\hat{\frak{sl}}(M+1|N+1))$ and vertex operators associated with the fundamental representations are constructed in terms of free bosonic fields. Character formulas of level-one irreducible highest weight modules of $\U_q(\hat{\frak{sl}}(2|1))$ are conjectured.
The $β$-delayed neutron decay of $^{17}$B was studied using a radioactive ion beam. The neutron energies, measured via time-of-flight, give information on states in $^{17}$C above the $^{16}$C + neutron threshold. States in $^{17}$C were found at excitation energies of 2.25(2) MeV, 2.64(2) MeV and 3.82(5) MeV, and possibly at 1.18(1) MeV. These low lying states are of possible interest for nuclear physics as well as for astrophysics.
One of the key ideas in describing the multiparticle production at high energies in the perturbative QCD is the angular ordering in successive soft-gluon emission. We analyse the angular distribution of particles in a jet, and investigate the corrections to the angular ordering. At a small angle from the jet direction, the angular ordering is exact at the next-to-leading order. At a large angle, the angular ordering overestimates the angular particle density by a factor $(1-γ\ln \cos^2(θ/2))$, where $γ$ is the anomalous dimension of the multiplicity. The $O(γ)$ correction restores the boost invariance of the cross section.
We evaluate the multiplicity of hadrons in the $e^+e^-$-annihilation at a given thrust $T$ in the modified leading-log approximation, including $O(\sqrt{α_s})$ corrections. The calculation is done at a large value of $τ=1-T$ by the use of the factorisation which takes place in the one-particle-inclusive cross section at a given $τ$. At a small $τ$, a different type of factorisation takes place, which also enable us to evaluate the multiplicity. Two approaches are compared numerically. Measuring this quantity near $τ=1/3$, we can determine the multiplicity ratio between a gluon-jet and a quark-jet.