  We have performed an ultrahigh-resolution angle-resolved photoemission
spectroscopy study of slightly-overdoped (Bi,Pb)2Sr2CuO6 to elucidate the
origin of pseudogap. By using a newly developed xenon-plasma light source, we
determined the comprehensive momentum and temperature dependences of the
superconducting gap and the pseudogap. We found that the antinodal pseudogap
persists far above the superconducting transition temperature and is smoothly
connected to the nodal gap. The characteristic temperature of the pseudogap
scales well with the superconducting-gap size irrespective of the momentum
location. The present experimental results point to the pairing origin of the
pseudogap.
