Using a data set corresponding to an integrated luminosity of d4e2b5b9f6fb7dd8b454ad4020fac" title="Click to view the MathML source">3 fb−1, collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV, the effective lifetime in the decay mode, d40d5fa82c18f0a7" title="Click to view the MathML source">τeff, is measured to be
τeff=1.479±0.034 (stat)±0.011 (syst) ps.
Assuming CP conservation, d40d5fa82c18f0a7" title="Click to view the MathML source">τeff corresponds to the lifetime of the light d499403821400614d11"> mass eigenstate. This is the first measurement of the effective lifetime in this decay mode.