  A new measurement of the $\theta_{13}$ mixing angle has been obtained at the
Daya Bay Reactor Neutrino Experiment via the detection of inverse beta decays
tagged by neutron capture on hydrogen. The antineutrino events for hydrogen
capture are distinct from those for gadolinium capture with largely different
systematic uncertainties, allowing a determination independent of the
gadolinium-capture result and an improvement on the precision of $\theta_{13}$
measurement. With a 217-day antineutrino data set obtained with six
antineutrino detectors and from six 2.9 GW$_{th}$ reactors, the rate deficit
observed at the far hall is interpreted as $\sin^22\theta_{13}=0.083\pm0.018$
in the three-flavor oscillation model. When combined with the
gadolinium-capture result from Daya Bay, we obtain
$\sin^22\theta_{13}=0.089\pm0.008$ as the final result for the
six-antineutrino-detector configuration of the Daya Bay experiment.

High Energy Physics - Experiment;Instrumentation and Detectors