\(B_0\) oscillation

\(B_0\) oscillation refers to the fact some of the \(B_0\) oscillate into \(\bar{B_0}\) before they decay.

For real data reconstruction, this doesn't require additional consideration, as we only know the quark content of the \(B\) mesons, be it \(B_0\) or \(\bar{B_0}\), before they decay.

However, for MC truth reconstruction (this applies to MCDecayTreeTuple only), we are concerned about the initial states of the \(B\) mesons. Instead of naively writing decay descriptors like this:

'${b0}[B~0 -> ${dst}(D*(2010)+ -> ${d0}(D0 -> ${k}K- ${pi}pi+) ${spi}pi+) ${mu}mu-]CC'

We need to take \(B_0\) oscillation into account:

'('
'${b0}[B~0 => ${dst}(D*(2010)+ => ${d0}(D0 => ${k}K- ${pi}pi+) ${spi}pi+) ${mu}mu- ${anu_mu}nu_mu~]CC'
'||'
'${b0}[B0 => ${dst}(D*(2010)+ => ${d0}(D0 => ${k}K- ${pi}pi+) ${spi}pi+) ${mu}mu- ${anu_mu}nu_mu~]CC'
')'