Four-body baryonic $B\to {\mathbf{B}}_1{\bar{\mathbf{B}}}_1^{\prime }{\mathbf{B}}_2{\bar{\mathbf{B}}}_2^{\prime }$ decays

Abstract

LHCb has recently reported the first observation of a four-body baryonic $B\to {\mathbf{B}}_1{\bar{\mathbf{B}}}_1^{\prime }{\mathbf{B}}_2{\bar{\mathbf{B}}}_2^{\prime }$ decay, where ${\mathbf{B}}_1{\bar{\mathbf{B}}}_1^{\prime }$ and ${\mathbf{B}}_2{\bar{\mathbf{B}}}_2^{\prime }$ represent the two pairs of octet baryon states. In our classification, the measured ${\bar{B}}^0\to p\bar{p}p\bar{p}$ decay is a tree dominated process via internal $W$-boson emission, whose branching fraction is explained as small as $2.2\times 10^{-8}$. We investigate for the first time the phenomenology of other tree and penguin dominated $B\to {\mathbf{B}}_1{\bar{\mathbf{B}}}_1^{\prime }{\mathbf{B}}_2{\bar{\mathbf{B}}}_2^{\prime }$ decays, and predict the presence of a double threshold effect, manifested as two peaks around $m_{{\mathbf{B}}_1{\bar{\mathbf{B}}}_1^{\prime }}\sim m_{{\mathbf{B}}_1}+m_{{\bar{\mathbf{B}}}_1^{\prime }}$ and $m_{{\mathbf{B}}_2{\bar{\mathbf{B}}}_2^{\prime }}\sim m_{{\mathbf{B}}_2}+m_{{\bar{\mathbf{B}}}_2^{\prime }}$ in the invariant mass spectra of ${\mathbf{B}}_1{\bar{\mathbf{B}}}_1^{\prime }$ and ${\mathbf{B}}_2{\bar{\mathbf{B}}}_2^{\prime }$, respectively. Moreover, we predict the following branching fractions: $\mathcal{B}(B^{-}\to n\bar{p}p\bar{p})=(1.7_{-0.2}^{+0.4}\pm 0.1_{-0.4}^{+0.7})\times 10^{-7}$, $\mathcal{B}(B^{-}\to \Lambda \bar{p}p\bar{p})=(7.4_{-0.2}^{+0.6}\pm 0.03_{-2.6}^{+3.6})\times 10^{-7}$, and $\mathcal{B}({\bar{B}}_s^0\to \Lambda \bar{\Lambda }p\bar{p})=(1.9_{-0.1}^{+0.3}\pm 0.01_{-0.6}^{+1.1})\times 10^{-7}$, which are accessible to experimental facilities.

Comments: 16 pages, 4 figures, 2 tables, matches published version