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We present the results of observations of the TeV binary LS I +61 303 withthe VERITAS telescope array between 2008 and 2010, at energies above 300 GeV.In the past, both ground-based gamma-ray telescopes VERITAS and MAGIC havereported detections of TeV emission near the apastron phases of the binaryorbit. The observations presented here show no strong evidence for TeV emissionduring these orbital phases; however, during observations taken in late 2010,significant emission was detected from the source close to the phase ofsuperior conjunction (much closer to periastron passage) at a 5.6 standarddeviation (5.6 sigma) post-trials significance. In total, between October 2008and December 2010 a total exposure of 64.5 hours was accumulated with VERITASon LS I +61 303, resulting in an excess at the 3.3 sigma significance level forconstant emission over the entire integrated dataset. The flux upper limitsderived for emission during the previously reliably active TeV phases (i.e.close to apastron) are less than 5% of the Crab Nebula flux in the same energyrange. This result stands in apparent contrast to previous observations by bothMAGIC and VERITAS which detected the source during these phases at >10% of theCrab Nebula flux. During the two year span of observations, a large amount ofX-ray data were also accrued on LS I +61 303 by the Swift X-ray Telescope (XRT)and the Rossi X-ray Timing Explorer Timing (RXTE) Proportional Counter Array(PCA). We find no evidence for a correlation between emission in the X-ray andTeV regimes during 20 directly overlapping observations. We also comment ondata obtained contemporaneously by the Fermi Large Area Telescope (LAT).

VERITAS Observations of the TeV Binary LS I +61 303 During 2008-2010