Evidence for the decay $X(3872)\to J/\psi \omega$

We present a study of the decays $B^{0,+}\to J/\psi {\pi }^{+}{\pi }^{-}{\pi }^0{K}^{0,+}$, using $467\times {10}^6$ $B\overline{B}$ pairs recorded with the BABAR detector. We present evidence for the decay mode $X(3872)\to J/\psi \omega$, with product branching fractions $\mathcal{B}(B^{+}\to X(3872)K^{+})\times \mathcal{B}(X(3872)\to J/\psi \omega )=[0.6\pm 0.2(\mathrm{stat})\pm 0.1(\mathrm{syst})]\times {10}^{-5}$, and $\mathcal{B}(B^0\to X(3872)K^0)\times \mathcal{B}(X(3872)\to J/\psi \omega )=[0.6\pm 0.3(\mathrm{stat})\pm 0.1(\mathrm{syst})]\times {10}^{-5}$. A detailed study of the ${\pi }^{+}{\pi }^{-}{\pi }^0$ mass distribution from $X(3872)$ decay favors a negative-parity assignment.

Figure 1

The $m_{3\pi }$ distribution for $B^{+}\to J/\psi {\pi }^{+}{\pi }^{-}{\pi }^0{K}^{+}$ candidates obtained as described in the text; the dashed vertical lines denote the central mass values of the $\eta$ and $\omega$ meson [27].

Figure 2

The corrected $m_{J/\psi \omega }$ distribution for (a) $B^{+}$, (b) $B^0$ decays; (c) (inset) shows the low-mass region of (a) in detail. The curves indicate the results of the fit.

Figure 3

The uncorrected $m_{J/\psi \omega }$ distributions for events with $3.8425<m_{J/\psi \omega }<3.8925\mathrm{GeV}/c^2$ for (a) $B^{+}$ and (b) $B^0$ decays; the open squares correspond to (a) $m_{3\pi }>0.7695$ and (b) $m_{3\pi }>0.7605\mathrm{GeV}/c^2$ [23]. The curves indicate the results of the fit.

Figure 4

The $m_{3\pi }$ distribution for events with $3.8625<m_{J/\psi \omega }<3.8825\mathrm{GeV}/c^2$ for (a) $B^{+}$, (b) $B^0$, and (c) the combined distribution. The vertical dashed line indicates the nominal $\omega$-meson mass [27]. In (c), the solid (dashed) histogram represents reconstructed MC $P$-wave ($S$-wave) events normalized to the number of data events.