Anti-charmed pentaquark from B decays

Abstract

We explore the possibility of observing the anti-charmed pentaquark state from the $Θ_c \bar{n} π^+$ decay of $B$ meson produced at $B$-factory experiments. We first show that the observed branching ratio of the $B^+$ to $ Λ^-_c p π^+$, as well as its open histograms, can be remarkably well explained by assuming that the decay proceeds first through the $π^+ \bar{D}^0$ (or $\bar{D}^{*0}$) decay, whose branching ratios are known, and then through the subsequent decay of the virtual $\bar{D}^0$ or $\bar{D}^{*0}$ mesons to $Λ_c^- p$, whose strength are calculated using previously fit hadronic parameters. We then note that the $Θ_c$ can be similarly produced when the virtual $\bar{D}^0$ or $\bar{D}^{*0}$ decay into an anti-nucleon and a $Θ_c$. Combining the present theoretical estimates for the ratio $g_{D N Λ_c} / g_{D N Θ_c} \sim 13 $ and $g_{D^* N Θ_c} \sim {1/3} g_{D N Θ_c}$, we find that the anti-charmed pentaquark $Θ_c$, which was predicted to be bound by several model calculations, can be produced via $B^+ \to Θ_c \bar{n} π^+$, and be observed from the $B$-factory experiments through the weak decay of $Θ_c \to p K^+ π^- π^- $.