Direct CP violation in internal W-emission dominated baryonic B decays

Abstract

AbstractThe observation of CP violation has been experimentally verified in numerous B decays but is yet to be confirmed in final states with half-spin particles. We focus our attention on baryonic B-meson decays mediated dominantly through internal W-emission processes and show that they are promising processes to observe for the first time the CP violating effects in B decays to final states with half-spin particles. Specifically, we study the $$\bar{B}^0\rightarrow p\bar{p}\pi ^0(\rho ^0)$$B¯0→pp¯π0(ρ0) and $$\bar{B}^0\rightarrow p\bar{p}\pi ^+\pi ^-$$B¯0→pp¯π+π- decays. We obtain $$\mathcal{B}(\bar{B}^0\rightarrow p\bar{p}\pi ^0)=(5.0\pm 2.1)\times 10^{-7}$$B(B¯0→pp¯π0)=(5.0±2.1)×10-7, in agreement with current data, and $$\mathcal{B}(\bar{B}^0\rightarrow p\bar{p}\rho ^0)\simeq \mathcal{B}(\bar{B}^0\rightarrow p\bar{p}\pi ^0)/3$$B(B¯0→pp¯ρ0)≃B(B¯0→pp¯π0)/3. Furthermore, we find $$\mathcal{A}_{CP}(\bar{B}^0\rightarrow p\bar{p}\pi ^0,p\bar{p}\rho ^0,p\bar{p}\pi ^+\pi ^-) =(-16.8\pm 5.4,-12.6\pm 3.0,-11.4\pm 1.9)\%$$ACP(B¯0→pp¯π0,pp¯ρ0,pp¯π+π-)=(-16.8±5.4,-12.6±3.0,-11.4±1.9)%. With measured branching fractions $$\mathcal{B}(\bar{B}^0\rightarrow p\bar{p}\pi ^0,p\bar{p}\pi ^+\pi ^-)\sim \mathcal{O}(10^{-6})$$B(B¯0→pp¯π0,pp¯π+π-)∼O(10-6), we point out that $$\mathcal{A}_{CP}\sim -(10-20)\%$$ACP∼-(10-20)% can be new observables for CP violation, accessible to the Belle II and/or LHCb experiments.