  We present the first large-acceptance measurement of event-wise mean
transverse momentum mean p_t fluctuations for Au-Au collisions at
nucleon-nucleon center-of-momentum collision energy sqrt{s_{NN}} = 130 GeV. The
observed non-statistical mean p_t fluctuations substantially exceed in
magnitude fluctuations expected from the finite number of particles produced in
a typical collision. The r.m.s. fractional width excess of the event-wise mean
p_t distribution is 13.7 +/- 0.1(stat) +/- 1.3(syst)% relative to a statistical
reference, for the 15% most-central collisions and for charged hadrons within
pseudorapidity range |eta|<1, 2pi azimuth and 0.15 < p_t < 2 GeV/c. The width
excess varies smoothly but non-monotonically with collision centrality, and
does not display rapid changes with centrality which might indicate the
presence of critical fluctuations. The reported mean p_t fluctuation excess is
qualitatively larger than those observed at lower energies and differs markedly
from theoretical expectations. Contributions to mean p_t mean fluctuations from
semi-hard parton scattering in the initial state and dissipation in the bulk
colored medium are discussed.
