出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We calculate energies and tensions of closed k-strings in (2+1)-dimensional SU(N) gauge theories
with N=4,5,6,8. When we study the dependence of the ground state energy on the string length,
we find that it is well described by a Nambu-Goto (NG) free bosonic string for large lengths.
At shorter lengths we see deviations which we fit, and this allows us to control the systematic
error involved in extracting the tension. We compare the resulting string tensions with Casimir
scaling, which we find to be lower than our data by 1%−4%. Extrapolating our results to N = ¥
we see that our data fits more naturally to 1/N rather than 1/N2 corrections. Finally, we see
that the full spectrum of the k-string states falls into sectors that belong to particular irreducible
representations of SU(N).
