Measurement of the time dependence of B^0-anti-B^0 oscillations using inclusive dilepton events

TL;DR

This study measures the time-dependent oscillations of B^0 mesons using dilepton events and neural network techniques to distinguish signal leptons, resulting in a precise determination of the mass difference between B^0 eigenstates.

Contribution

The paper introduces a neural network method to effectively separate signal from background in B^0 oscillation measurements, providing a new approach for analyzing time-dependent B meson behavior.

Findings

Measured the B^0-anti-B^0 mass difference as (0.507±0.015±0.022) x 10^{12} hbar-s^{-1}.

Reconstructed decay time differences using dilepton events from BABAR data.

Demonstrated the effectiveness of neural networks in flavor tagging for B meson oscillation studies.

Abstract

A preliminary study of time dependence of B^0-anti-B^0 oscillations using dilepton events is presented. The flavor of the B meson is determined by the charge sign of the lepton. To separate signal leptons from cascade and fake leptons we have used a method which combines several discriminating variables in a neural network. The time evolution of the oscillations is studied by reconstructing the time difference between the decays of the B mesons produced by the Y(4S) decay. With an integrated luminosity of 7.7 fb-1 collected on resonance by BABAR at the PEP-II asymmetric B Factory, we measure the difference in mass of the neutral B eigenstates, Delta_mB0, to be (0.507+/-0.015+/-0.022) x 10^{12} hbar-s^{-1}.