Isospin Considerations in Correlations of Pions and $B$ mesons

The correlations between a $B$ meson and a pion produced nearby in phase space should respect isospin reflection symmetry $I_3\to -I_3$. Thus, one generally expects similar ${\pi }^{+}{B}^0$ and ${\pi }^{-}{B}^{+}$ correlations (non-exotic channels), and similar ${\pi }^{-}{B}^0$ and ${\pi }^{+}{B}^{+}$ correlations (exotic channels). Exceptions include (a) fragmentation processes involving exchange of quarks with the producing system, (b) misidentification of charged kaons as charged pions, and © effects of decay products of the associated $\bar{B}$. All of these can affect the apparent signal for correlations of charged $B$ mesons with charged hadrons. The identification of the flavor of neutral $B$ mesons through the decay $B^0\to K^{\ast 0}J\mathrm{/}\psi$ requires good particle identification in order that the decay $K^{\ast 0}\to K^{+}{\pi }^{-}$ not be mistaken for ${\bar{K}}^{\ast 0}\to K^{-}{\pi }^{+}$, in which case the correlations of neutral $B$ mesons with hadrons can be underestimated.