Study of the baryonic $B$ decay $B^{-}\to {\mathit{\Sigma }}_c^{++}\overline{p}{\pi }^{-}{\pi }^{-}$

We report the measurement of the baryonic $B$ decay $B^{-}\to {\mathit{\Sigma }}_c^{++}\overline{p}{\pi }^{-}{\pi }^{-}$. Using a data sample of $467\times {10}^6$ $B\overline{B}$ pairs collected with the BABAR detector at the PEP-II storage ring at SLAC, the measured branching fraction is $(2.98\pm {0.16}_{(\mathrm{stat})}\pm {0.15}_{(\mathrm{syst})}\pm {0.77}_{({\Lambda }_{\mathrm{c}})})\times {10}^{-4}$, where the last error is due to the uncertainty in $\mathcal{B}({\mathit{\Lambda }}_{\mathrm{c}}^{+}\to p{K}^{-}{\pi }^{+})$. The data suggest the existence of resonant subchannels $B^{-}\to {\mathit{\Lambda }}_c(2595{)}^{+}\overline{p}{\pi }^{-}$ and, possibly, $B^{-}\to {\mathit{\Sigma }}_c^{++}{\overline{\mathit{\Delta }}}^{--}{\pi }^{-}$. We see unexplained structures in $m({\mathit{\Sigma }}_c^{++}{\pi }^{-}{\pi }^{-})$ at $3.25\mathrm{GeV}/c^2$, $3.8\mathrm{GeV}/c^2$, and $4.2\mathrm{GeV}/c^2$.

Figure 1

Fitted $\Delta M$ distribution for $B$ candidates in data. All candidates are required to satisfy the selection criteria on $m_{\mathrm{ES}}$, $m_{p{K}^{-}{\pi }^{+}}$, and $\Delta E$.

Figure 2

Fitted $\Delta E$ distribution in data with selection criteria applied to $m_{p{K}^{-}{\pi }^{+}}$, $m_{\mathrm{ES}}$, and $\Delta M$. The goodness of the fit is ${\chi }^2/\mathrm{dof}=36/40$. The $\Delta E$ signal region is between $-60\mathrm{MeV}$ and 40 MeV and is enclosed by the two sideband regions that each have a width of 50 MeV.

Figure 3

$\Delta E$ distribution for $B^{-}\to {\mathit{\Sigma }}_c^{++}\overline{p}{\pi }^{-}{\pi }^{-}$ candidates in data. The points with error bars represent the number of ${\mathit{\Sigma }}_c^{++}$ candidates $N_{\mathrm{sig}}^i$ from a fit to $\Delta M\equiv m({\mathit{\Lambda }}_{\mathrm{c}}^{+}{\pi }^{+})-m({\mathit{\Lambda }}_{\mathrm{c}}^{+})$. All signal parameters for the $\Delta E$ distribution, except $N_{\mathrm{sig}}$, are fixed to those shown in Table 1.

Figure 4

The $m({\mathit{\Sigma }}_c^{++}{\pi }_{\mathrm{s}}^{-})$ distribution in data (points with error bars) and for simulated four-body phase space decays (histogram). The distribution in data results from a sideband subtraction in $\Delta E$ according to the definition in Fig. 2.

Figure 5

The $m(\overline{p}{\pi }^{-})$ distribution in data and simulated four-body phase space decays. The shaded vertical ranges represent a width of one $\Gamma$ and are centered at the average mass of ${\overline{\mathit{\Delta }}}^{--}(1232)$ and ${\overline{\mathit{\Delta }}}^{--}(1620)$, respectively. The parameters are taken from the RPP [1]. The range of ${\overline{\mathit{\Delta }}}^{--}(1600)$ is not drawn since its parameters have large uncertainties.

Figure 6

The $m({\mathit{\Sigma }}_c^{++}{\pi }^{-})$ distribution in data after efficiency correction and $\Delta E$-sideband subtraction. The solid line shows four-body phase space decays. The shaded vertical ranges represent a width of one $\Gamma$ and are centered at the average mass of the respective ${\mathit{\Lambda }}_c^{*+}$ resonance. The parameters are taken from the RPP [1].

Figure 7

The $m({\mathit{\Sigma }}_c^{++}{\pi }^{-}{\pi }^{-})$ distribution in data and simulated four-body phase space decays. The histogram in data includes efficiency correction and $\Delta E$-sideband subtraction according to the definition in Fig. 2.