Measurements of the Decays $B^0 \to \bar{D}^0\proton\antiproton$, $B^0 \to \bar{D}^{*0}\proton\antiproton$, $B^0 \to D^{-}\proton\antiproton\pi^+$, and $B^0 \to D^{*-}\proton\antiproton\pi^+$

TL;DR

This paper reports precise measurements of branching fractions for specific $B^0$ decays involving protons, searches for charmed pentaquarks, and observes low-mass enhancements in decay products, providing insights into baryonic $B$ decays.

Contribution

It provides the first detailed measurements of these $B^0$ decay modes and sets limits on charmed pentaquark production, revealing decay structure anomalies.

Findings

Measured branching fractions with statistical and systematic uncertainties.

Set upper limits on $ heta_c(3100)$ pentaquark production in $B^0$ decays.

Observed low $par{p}$ mass enhancement and deviations from phase-space in invariant mass spectra.

Abstract

We present measurements of branching fractions of $B^0$ decays to multi-body final states containing protons, based on 232 million $\Upsilon(4S)\to B\bar{B}$ decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy $B$ factory. We measure the branching fractions ${\cal B}(B^0 \to \bar{D}^0\proton\antiproton)=(1.13\pm0.06\pm0.08)\times 10^{-4}$, ${\cal B}(B^0 \to \bar{D}^{*0}\proton\antiproton)=(1.01\pm0.10\pm0.09)\times 10^{-4}$, ${\cal B}(B^0 \to D^{-}\proton\antiproton\pi^+)=(3.38\pm0.14\pm0.29)\times 10^{-4}$, and ${\cal B}(B^0 \to D^{*-}\proton\antiproton\pi^+)=(4.81\pm0.22\pm0.44)\times 10^{-4}$ where the first error is statistical and the second systematic. We present a search for the charmed pentaquark state, $\Theta_c(3100)$ observed by H1 and put limits on the branching fraction ${\cal B} (B^0 \to \Theta_c \antiproton\pi^+)\times{\cal B}(\Theta_c \to D^{*-}\proton)<14\times10^{-6}$ and ${\cal B}(B^0 \to \Theta_c \antiproton\pi^+)\times{\cal B}(\Theta_c\to D^-\proton)<9\times10^{-6}$. Upon investigation of the decay structure of the above four $B^{0}$ decay modes, we see an enhancement at low $p\bar{p}$ mass and deviations from phase-space in the $\bar{D}\bar{p}$ and $\bar{D}p$ invariant mass spectra.