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

Abstract

The decays ${\Lambda }_b^0\to \psi (2S)p{K}^{-}$ and ${\Lambda }_b^0\to J/\psi {\pi }^{+}{\pi }^{-}p{K}^{-}$ are observed in a data sample corresponding to an integrated luminosity of 3fb${}^{-1}$, collected in proton-proton collisions at 7 and 8TeV centre-of-mass energies by the LHCb detector. The $\psi (2S)$ mesons are reconstructed through the decay modes $\psi (2S)\to {\mu }^{+}{\mu }^{-}$ and $\psi (2S)\to J/\psi {\pi }^{+}{\pi }^{-}$. The branching fractions relative to that of ${\Lambda }_b^0\to J/\psi p{K}^{-}$ are measured to be \begin{eqnarray*} \frac{\mathcal{B}(Λ_b^0 \to ψ(2S) pK^-)} {\mathcal{B}(Λ_b^0 \to J/ψpK^-)} & = & (20.70\pm 0.76\pm 0.46\pm 0.37)\times10^{-2} \,, \frac{\mathcal{B}(Λ_b^0 \to J/ψπ^+ π^- pK^-)} {\mathcal{B}(Λ_b^0 \to J/ψpK^-)} & = & (20.86\pm 0.96\pm 1.34)\times10^{-2} \,, \end{eqnarray*} where the first uncertainties are statistical, the second are systematic and the third is related to the knowledge of $J/\psi$ and $\psi (2S)$ branching fractions. The mass of the ${\Lambda }_b^0$ baryon is measured to be $$M({\Lambda }_b^0)=5619.65\pm 0.17\pm 0.17\mathrm{MeV}/c^2,$$ where the uncertainties are statistical and systematic.

arXiv comment21 pages, 6 figures. All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-060.html

References in corpus (40)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• A Brief Introduction to PYTHIA 8.1
• Big-Bang Nucleosynthesis
• Heavy Quark Symmetry
• Observation of $J/\psi p$ resonances consistent with pentaquark states in ${\Lambda }_b^0\to J/\psi K^{-}p$ decays
• LHCb Detector Performance
• sPlot: a statistical tool to unfold data distributions
• The LHCb Trigger and its Performance in 2011
• Performance of the LHCb RICH detector at the LHC
• Decay Chain Fitting with a Kalman Filter
• Performance of the LHCb Vertex Locator
• Measurement of the track reconstruction efficiency at LHCb
• Mass distributions marginalized over per-event errors
• Observation of $J/\psi$ pair production in pp collisions at $\sqrt{s}=7TeV$
• Study of the production of ${\Lambda }_b^0$ and ${\overline{B}}^0$ hadrons in $pp$ collisions and first measurement of the ${\Lambda }_b^0\to J/\psi p{K}^{-}$ branching fraction
• Measurement of the Λ_b^0, Ξ_b^- and Ω_b^- baryon masses
• Performance of the Muon Identification at LHCb
• Precision measurement of D meson mass differences
• Measurement of $B_c^{+}$ production in proton-proton collisions at $\sqrt{s}=8$ TeV
• Measurement of b-hadron masses
• Precision measurement of the ratio of the ${\Lambda }_b^0$ to ${\overline{B}}^0$ lifetimes
• Precision measurement of the mass and lifetime of the ${\Xi }_b^0$ baryon
• Studies of beauty baryon decays to $D^{0}p{h}^{-}$ and ${\Lambda }_c^{+}{h}^{-}$ final states
• Study of beauty hadron decays into pairs of charm hadrons
• Precision measurement of the mass and lifetime of the Xi_b^- baryon
• Prompt K_short production in pp collisions at sqrt(s)=0.9 TeV
• Measurement of the Lambda_b lifetime and mass in the ATLAS experiment
• Mass and lifetime measurements of bottom and charm baryons in $p\bar{p}$ collisions at $\sqrt{s}= 1.96 TeV
• Measurement of relative branching fractions of B decays to $\psi (2S)$ and $J/\psi$ mesons
• Measurement of the production fraction times branching fraction f(b --> Λ_b)B(Λ_b --> J/ψΛ)
• Observations of $B_s^0\to \psi (2S)\eta$ and $B_{(s)}^0\to \psi (2S){\pi }^{+}{\pi }^{-}$ decays
• Measurement of $\sigma ({\Lambda }_b)/\sigma (B^0)\times BR({\Lambda }_b\to {\Lambda }_c{\pi }^{-})/BR(B^0\to D^{+}{\pi }^{-})$ in $p\bar{p}$ Collisions at $\sqrt{s}=1.96$ TeV
• Measurement of the branching fraction ratio $\mathcal{B}(B_c^{+}\to \psi (2S){\pi }^{+})/\mathcal{B}(B_c^{+}\to J/\psi {\pi }^{+})$
• Measurement of the Branching Fractions for J/psi to ell^+ ell^-
• Measurement of the branching ratio $\Gamma ({\Lambda }_b^0\to \psi (2S){\Lambda }^0)/\Gamma ({\Lambda }_b^0\to J/\psi {\Lambda }^0)$ with the ATLAS detector
• Observation of $B_s^0\to {\chi }_{c1}\varphi$ decay and study of $B^0\to {\chi }_{c1,2}{K}^{\ast 0}$ decays
• Evidence for the decay $B_c^{+}\to J/\psi 3{\pi }^{+}2{\pi }^{-}$
• Branching Fraction Measurements of the Color-Suppressed Decays B0bar to D(*)0 pi0, D(*)0 eta, D(*)0 omega, and D(*)0 eta_prime and Measurement of the Polarization in the Decay B0bar to D*0 omega
• Measurement of the branching fractions for psi(2S)-->e+e- and psi(2S)-->mu+mu-

Cited by in corpus (17)

• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of summer 2016
• Hadronic molecules
• The $XYZ$ states: experimental and theoretical status and perspectives
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2018
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Observation of two resonances in the ${\Lambda }_b^0{\pi }^{\pm }$ systems and precise measurement of ${\Sigma }_b^{\pm }$ and ${\Sigma }_b^{\ast \pm }$ properties
• Observation of new resonances in the ${\Lambda }_b^0{\pi }^{+}{\pi }^{-}$ system
• Observation of a new baryon state in the ${\Lambda }_b^0{\pi }^{+}{\pi }^{-}$ mass spectrum
• Observation of the decays ${\Lambda }_b^0\to {\chi }_{c1}p{K}^{-}$ and ${\Lambda }_b^0\to {\chi }_{c2}p{K}^{-}$
• The Status of ${\Xi }_{cc}^{++}$ Baryon: investigating quark-diquark model
• Study of $B_s^0\to J/\psi {\pi }^{+}{\pi }^{-}{K}^{+}{K}^{-}$ decays
• The impact of composition choices on solar evolution: age, helio- and asteroseismology, and neutrinos
• Observation of the ${\Lambda }_b^0\to {\chi }_{c1}(3872)p{K}^{-}$ decay
• Standard solar models: a perspective from updated solar neutrino fluxes and the gravity-mode period spacing
• Observation of the ${\Lambda }_{\mathrm{b}}^0$ $\to$ J/$\psi \Lambda \varphi$ decay in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Observation of the ${\Lambda }_b^0\to {\Lambda }_c^{+}{K}^{+}{K}^{-}{\pi }^{-}$ decay
• $N^{\ast }$ states with hidden charm and a three-body nature