Search for CPT and Lorentz Violation in B0-B0bar Oscillations with Inclusive Dilepton Events

Abstract

We report preliminary results of a search for CPT and Lorentz violation in B0-B0bar oscillations using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II B Factory. Using a sample of 232 million BBbar pairs, we search for time-dependent variations in the complex CPT parameter z = z0 + z1*cos(Omega*t^ + phi) where Omega is the Earth's sidereal frequency and t^ is sidereal time. We measure Im(z0) = (-14.1 +- 7.3(stat) +- 2.4(syst)) x 10E-3, DeltaGamma*Re(z0) = (-7.2 +- 4.1(stat) +- 2.1(syst)) x 10E-3 ps-1, Im(z1) = (-24.0 +- 10.7(stat) +- 5.9(syst)) x 10E-3, and DeltaGamma*Re(z1) = (-18.8 +- 5.5(stat) +- 4.0(syst)) x 10E-3 ps-1, where DeltaGamma is the difference between the decay rates of the neutral B mass eigenstates. The statistical correlation between the measurements of Im(z0) and DeltaGamma*Re(z0) is 76%; between Im(z1) and DeltaGamma*Re(z1) it is 79%. These results are used to evaluate expressions involving coefficients for Lorentz and CPT violation in the general Lorentz-violating standard-model extension. In a complementary approach, we examine the spectral power of periodic variations in z over a wide range of frequencies and find no significant signal.