XMM-Newton X-ray Observation of the High-magnetic-field Radio Pulsar PSR J1734-3333

Using observations made with the XMM-Newton Observatory, we report the probable X-ray detection of the high-magnetic-field radio pulsar PSR J1734-3333. This pulsar has an inferred surface dipole magnetic field of B = 5.2 × 10¹³ G, just below that of one anomalous X-ray pulsar. We find that the pulsar has an absorbed 0.5-2.0 keV flux of (5-15) × 10^-15 erg s^-1 cm^-2 and that its X-ray luminosity L _X is well below its spin-down luminosity \dot{E}, with L_{{X}}<0.1 \dot{E}. No pulsations were detected in these data although our derived upper limit is unconstraining. Like most of the other high-B pulsars, PSR J1734-3333 is X-ray faint with no sign of magnetar activity. We tabulate the properties of this and all other known high-B radio pulsars with measured thermal X-ray luminosities or luminosity upper limits, and speculate on a possible correlation between L _X and B.