Study of beauty hadron decays into pairs of charm hadrons

Abstract

First observations of the decays ${\Lambda }_b^0\to {\Lambda }_c^{+}{D}_{(s)}^{-}$ are reported using data corresponding to an integrated luminosity of $3{\mathrm{fb}}^{-1}$ collected at 7 and 8 TeV center-of-mass energy in proton-proton collisions with the LHCb detector. In addition, the most precise measurement of the branching fraction $\mathcal{B}(B_s^0\to D^{+}{D}_s^{-})$ is made and a search is performed for the decays $B_{(s)}^0\to {\Lambda }_c^{+}{\Lambda }_c^{-}$. The results obtained are \begin{eqnarray*} \mathcal{B}(Λ_b^0 \to Λ_c^+ D^-)/\mathcal{B}(Λ_b^0 \to Λ_c^+ D_{s}^-) &=& 0.042 \pm 0.003({\rm stat}) \pm 0.003({\rm syst}), \left[\frac{\mathcal{B}(Λ_b^0 \to Λ_c^+ D_{s}^-)}{\mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}_d^0 \to D^+D_s^-)}\right]\big/\left[\frac{\mathcal{B}(Λ_b^0 \to Λ_c^+π^-)}{\mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}_d^0 \to D^+π^-)}\right] &=& 0.96 \pm 0.02({\rm stat}) \pm 0.06({\rm syst}), \mathcal{B}(B_s^0 \to D^+D_s^-)/\mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}_d^0 \to D^+D_s^-) &=& 0.038\pm0.004({\rm stat})\pm0.003({\rm syst}), \mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}^0 \to Λ_c^+ Λ_c^-)/\mathcal{B}({\kern 0.2em}\overline{\kern -0.2em B}_d^0 \to D^+D_s^-) & < & 0.0022\; [95\% \; {\rm C.L.}], \mathcal{B}(B^0_{s} \to Λ_c^+ Λ_c^-)/\mathcal{B}(B_s^0 \to D^+D_s^-) & < & 0.30\; [95\% \; {\rm C.L.}]. \end{eqnarray*} Measurement of the mass of the ${\Lambda }_b^0$ baryon relative to the $B^0$ meson gives $M({\Lambda }_b^0)-M(B^0)=339.72\pm 0.24(\mathrm{stat})\pm 0.18(\mathrm{syst})$ MeV$/c^2$. This result provides the most precise measurement of the mass of the ${\Lambda }_b^0$ baryon to date.

References in corpus (7)

• PYTHIA 6.4 Physics and Manual
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of summer 2016
• Mass distributions marginalized over per-event errors
• Bottom Baryons
• Measurement of the Branching Fraction Br(Lambda_c+ -> p K- pi+)
• Model-Independent Bottom Baryon Mass Predictions in the 1/N Expansion
• Universal Constituent-Quark Model for Baryons

Cited by in corpus (33)

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• Mass distributions marginalized over per-event errors
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• Precise measurement of the $f_s/f_d$ ratio of fragmentation fractions and of $B_s^0$ decay branching fractions
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• Precision measurement of the mass and lifetime of the ${\Xi }_b^0$ baryon
• Observation of the ${\Lambda }_b^0\to J/\psi p{\pi }^{-}$ decay
• Precision measurement of the mass and lifetime of the Xi_b^- baryon
• Study of excited ${\Lambda }_{\mathrm{b}}^0$ states decaying to ${\Lambda }_{\mathrm{b}}^0{\pi }^{+}{\pi }^{-}$ in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Color-allowed Bottom Baryon to Charmed Baryon non-leptonic Decays
• Observations of ${\Lambda }_b^0\to \Lambda K^{+}{\pi }^{-}$ and ${\Lambda }_b^0\to \Lambda K^{+}{K}^{-}$ decays and searches for other ${\Lambda }_b^0$ and ${\Xi }_b^0$ decays to $\Lambda h^{+}{h}^{\prime -}$ final states
• First observation of the radiative decay ${\Lambda }_b^0\to \Lambda \gamma$
• Standard Model Predictions and New Physics Sensitivity in B->DD Decays
• Observation of ${\Lambda }_b^0\to \psi (2S)p{K}^{-}$ and ${\Lambda }_b^0\to J/\psi {\pi }^{+}{\pi }^{-}p{K}^{-}$ decays and a measurement of the ${\Lambda }_b^0$ baryon mass
• Fragmentation fractions of two-body b-baryon decays
• Pentaquarks from intrinsic charms in ${\Lambda }_b$ decays
• Study of $B_s^0\to J/\psi {\pi }^{+}{\pi }^{-}{K}^{+}{K}^{-}$ decays
• Charmful two-body anti-triplet $b$-baryon decays
• Axial-Vector Emitting Weak Nonleptonic Deacys of ${\Omega }_c^0$ Baryon
• Search for $B_c^{+}$ decays to two charm mesons
• Observation of the decay ${\Lambda }_b^0\to \psi (2S)p{\pi }^{-}$
• Simultaneous extractions of $|V_{ub}|$ and $|V_{cb}|$ with only the exclusive ${\Lambda }_b$ decays
• Sum rule for the partial decay rates of bottom hadrons based on the dynamical supersymmetry of the $\bar{s}$ quark and the $ud$ diquark
• Analysis of $b\to c\tau {\bar{\nu }}_{\tau }$ anomalies using weak effective Hamiltonian with complex couplings
• Observation of ${\Lambda }_b^0\to {\Lambda }_c^{+}{\bar{D}}^{(\ast )0}{K}^{-}$ and ${\Lambda }_b^0\to {\Lambda }_c^{+}{D}_s^{\ast -}$ decays
• Observation of the ${\Lambda }_b^0\to {\Lambda }_c^{+}{K}^{+}{K}^{-}{\pi }^{-}$ decay
• First observation of the ${\Lambda }_b^0\to {\Lambda }_c^{+}{D}_s^{-}{K}^{+}{K}^{-}$ decay and search for pentaquarks in the ${\Lambda }_c^{+}{D}_s^{-}$ system
• First observation of the ${\overline{B}}_s^0\to {\Lambda }_c^{+}{\overline{\Lambda }}_c{}^{-}$ decay and evidence for the ${\overline{B}}^0\to {\Lambda }_c^{+}{\overline{\Lambda }}_c{}^{-}$ decay
• Observation of ${\Lambda }_b^0\to D^{+}p{\pi }^{-}{\pi }^{-}$ and ${\Lambda }_b^0\to D^{\ast +}p{\pi }^{-}{\pi }^{-}$ decays