出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：J/Y and hc above the QCD critical temperature Tc are studied in anisotropic quenched lattice
QCD, considering whether the c ¯ c systems above Tc are compact quasi-bound states or scattering
states. We adopt the standard Wilson gauge action and O(a)-improved Wilson quark action with
renormalized anisotropy as/at = 4 at b = 6.10 on 163 ×(14−26) lattices, which correspond to
the spatial lattice volume V ´ L3 ' (1.55fm)3 and temperatures T ' (1.11−2.07)Tc. To clarify
whether compact charmonia survive in the deconfinement phase, we investigate spatial boundarycondition
dependence of the energy of the c ¯ c systems above Tc. In fact, for low-lying c ¯ c scattering
states, there appears a significant energy difference DE ´ E(APBC)−E(PBC) between periodic
and anti-periodic boundary conditions as DE ' 2
p
m2c
+3p2/L2 −2mc (mc: charm quark mass)
on the finite-volume lattice. In contrast, for compact charmonia, there is no significant energy
difference between periodic and anti-periodic boundary conditions. As a lattice QCD result, we
find almost no spatial boundary-condition dependence for the energy of the c ¯ c system in J/Y and
hc channels for T ' (1.11−2.07)Tc, which indicates that J/Y and hc would survive as compact
c ¯ c quasi-bound states below 2Tc.
