# EP Articles

2017-07-07
07:35
 Observation of the doubly charmed baryon $\Xi_{cc}^{++}$ / LHCb Collaboration A highly significant structure is observed in the $\Lambda_c^+K^-\pi^+\pi^+$ mass spectrum, where the $\Lambda_c^+$ baryon is reconstructed in the decay mode $pK^-\pi^+$. The structure is consistent with originating from a weakly decaying particle, identified as the doubly charmed baryon $\Xi_{cc}^{++}$. [...] LHCB-PAPER-2017-018; CERN-EP-2017-156; arXiv:1707.01621.- 2017-09-11 - 10 p. - Published in : Phys. Rev. Lett. 119 (2017) 112001 Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP; Supplementary information: ZIP; External links: conference slides; INTERACTIONS

2017-06-24
09:59
 Study of charmonium production in ${b}$-hadron decays and first evidence for the decay ${{{B}} ^0_{{s}}} \!\rightarrow \phi \phi \phi$ / LHCb Collaboration Using decays to $\phi$-meson pairs, the inclusive production of charmonium states in $b$-hadron decays is studied with $pp$ collision data corresponding to an integrated luminosity of $3.0fb^{-1}$, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. Denoting by $B_C\equiv B(b\to CX)\times B(C\to\phi\phi)$ the inclusive branching fraction of a $b$ hadron to a charmonium state $C$ that decays into a pair of $\phi$ mesons, ratios $R^{C1}_{C2}\equiv B_{C1}/B_{C2}$ are determined as $R^{\chi_{c0}}_{\eta_c(1S)}=0.147\pm0.023\pm0.011$, $R^{\chi_{c1}}_{\eta_c (1S)}=0.073\pm0.016\pm0.006$, $R^{\chi_{c2}}_{\eta_c (1S)}=0.081\pm0.013\pm0.005$, $R^{\chi_{c1}}_{\chi_{c0}}=0.50\pm0.11\pm0.01$, $R^{\chi_{c2}}_{\chi_{c0}}=0.56\pm0.10\pm0.01$ and $R^{\eta_c (2S)}_{\eta_c(1S)}=0.040\pm0.011\pm0.004$. [...] LHCB-PAPER-2017-007; CERN-EP-2017-099; arXiv:1706.07013; LHCB-PAPER-2017-007.- Springer, 2017-09-14 - 31 p. - Published in : Eur. Phys. J. C 77 (2017) 609 Article from SCOAP3: PDF; Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP; Supplementary information: ZIP;

2017-05-18
09:34
 Test of lepton universality with $B^{0} \rightarrow K^{*0}\ell^{+}\ell^{-}$ decays / LHCb Collaboration A test of lepton universality, performed by measuring the ratio of the branching fractions of the $B^{0} \rightarrow K^{*0}\mu^{+}\mu^{-}$ and $B^{0} \rightarrow K^{*0}e^{+}e^{-}$ decays, $R_{K^{*0}}$, is presented. The $K^{*0}$ meson is reconstructed in the final state $K^{+}\pi^{-}$, which is required to have an invariant mass within 100$\mathrm{\,MeV}c^2$ of the known $K^{*}(892)^{0}$ mass. [...] LHCB-PAPER-2017-013; CERN-EP-2017-100; arXiv:1705.05802; LHCB-PAPER-2017-013.- Geneva : CERN, 2017-08-16 - Published in : JHEP 08 (2017) 055 Article from SCOAP3: PDF; Preprint: PDF; Related data file(s): ZIP;

2017-05-12
10:56
 Measurement of $B^{0}_{s}$ and $D^{-}_{s}$ meson lifetimes / LHCb Collaboration We report on a measurement of the flavor-specific $B^{0}_{s}$ lifetime and of the $D^{-}_{s}$ lifetime using proton-proton collisions at center-of-mass energies of 7 and 8 TeV, collected by the LHCb experiment and corresponding to 3.0 fb$^{-1}$ of integrated luminosity. Approximately 407 000 $B^{0}_{s} \rightarrow D^{(*)-}_{s} \mu^{+}\nu_\mu$ decays are partially reconstructed in the $K^{+}K^{-}\pi^{-}\mu^{+}$ final state. [...] CERN-EP-2017-070; LHCB-PAPER-2017-004; arXiv:1705.03475.- Geneva : CERN, 2017-09-08 - 10 p. - Published in : Phys. Rev. Lett. 119 (2017) 101801 Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP; Supplementary material: PDF; Supplementary material (zip): ZIP;

2017-05-08
14:53
 Observation of five new narrow $\Omega_c^0$ states decaying to $\Xi^+_c K^-$ / LHCb Collaboration The $\Xi^+_c K^-$ mass spectrum is studied with a sample of $pp$ collision data corresponding to an integrated luminosity of 3.3 fb$^{-1}$, collected by the LHCb experiment. The $\Xi^+_c$ is reconstructed in the decay mode $pK^- \pi^+$. [...] LHCB-PAPER-2017-002; CERN-EP-2017-037; arXiv:1703.04639; LHCB-PAPER-2017-002.- Geneva : CERN, 2017-05-02 - 10 p. - Published in : Phys. Rev. Lett. 118 (2017) 182001 Fulltext: 10.1103_PhysRevLett.118.182001 - PDF; arXiv:1703.04639 - PDF; Preprint: PDF; Supplementary information: ZIP;

2017-05-02
11:15
 Resonances and $CP$ violation in $B_s^0$ and $\overline{B}_s^0 \to J/\psi K^+K^-$ decays in the mass region above the $\phi(1020)$ / LHCb Collaboration The decays of $B_s^0$ and $\overline{B}_s^0$ mesons into the $J/\psi K^+K^-$ final state are studied in the $K^+K^-$ mass region above the $\phi(1020)$ meson in order to determine the resonant substructure and measure the $CP$-violating phase, $\phi_s$, the decay width, $\Gamma_s$, and the width difference between light and heavy mass eigenstates, $\Delta\Gamma_s$. A decay-time dependent amplitude analysis is employed. [...] CERN-EP-2017-062; LHCB-PAPER-2017-008; arXiv:1704.08217; LHCB-PAPER-2017-008.- Geneva : CERN, 2017-08-09 - 28 p. - Published in : JHEP 08 (2017) 037 Article from SCOAP3: PDF; Figures: ZIP; Preprint: PDF; External link: Previous draft version

2017-04-27
14:36
 Observation of charmless baryonic decays $B^0_{(s)} \to p \overline{p} h^+ h^{\prime-}$ / LHCb Collaboration Decays of $B^0$ and $B_{s}^0$ mesons to the charmless baryonic final states $p \overline{p} h^+ h^{\prime-}$, where $h$ and $h^\prime$ each denote a kaon or a pion, are searched for using the LHCb detector. The analysis is based on a sample of proton-proton collision data collected at center-of-mass energies of $7$ and $8\,$TeV, corresponding to an integrated luminosity of $3\,$fb$^{-1}$. [...] LHCB-PAPER-2017-005; CERN-EP-2017-052; arXiv:1704.08497; LHCB-PAPER-2017-005.- Geneva : CERN, 2017-09-27 - 10 p. - Published in : Phys. Rev. D 96 (2017) 051103 Figures: ZIP; Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP; External link: Previous draft version

2017-04-26
10:11
 Observation of the decays $\Lambda_b^0 \to \chi_{c1} p K^-$ and $\Lambda_b^0 \to \chi_{c2} p K^-$ / LHCb Collaboration The first observation of the decays $\Lambda_b^0 \to \chi_{c1} p K^-$ and $\Lambda_b^0 \to \chi_{c2} p K^-$ is reported using a data sample corresponding to an integrated luminosity of $3.0$ fb$^{-1}$, collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies of 7 and 8 TeV. The following ratios of branching fractions are measured \begin{eqnarray*} \frac{{\cal B}(\Lambda_b^0 \to \chi_{c1} p K^-)}{{\cal B}(\Lambda_b^0 \to J/\psi p K^-)} = 0.242 \pm 0.014 \pm 0.013 \pm 0.009, \frac{{\cal B}(\Lambda_b^0 \to \chi_{c2} p K^-)}{{\cal B}(\Lambda_b^0 \to J/\psi p K^-)} = 0.248 \pm 0.020 \pm 0.014 \pm 0.009, \frac{{\cal B}(\Lambda_b^0 \to \chi_{c2} p K^-)}{{\cal B}(\Lambda_b^0 \to \chi_{c1} p K^-)} = 1.02 \pm 0.10 \pm 0.02 \pm 0.05, \end{eqnarray*} where the first uncertainty is statistical, the second systematic and the third due to the uncertainty on the branching fractions of the $\chi_{c1}\to J/\psi\gamma$ and $\chi_{c2} \to J/\psi\gamma$ decays. [...] LHCB-PAPER-2017-011; CERN-EP-2017-073; arXiv:1704.07900.- Geneva : CERN, 2017-08-08 - 11 p. - Published in : Phys. Rev. Lett. 119 (2017) 062001 Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP; External link: Previous draft version

2017-04-26
07:45
 Observation of the $B^+ \to D^{*-}K^+\pi^+$ decay / LHCb Collaboration The $B^+ \to D^{*-}K^+\pi^+$ decay potentially provides an excellent way to investigate charm meson spectroscopy. The decay is searched for in a sample of proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of $3~{\rm fb}^{-1}$. [...] CERN-EP-2017-064; LHCB-PAPER-2017-006; arXiv:1704.07581.- Geneva : CERN, 2017-07-19 - 10 p. - Published in : Phys. Rev. D 96 (2017) 011101 Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP;

2017-03-20
12:28
 Measurement of the $B^0_s\to\mu^+\mu^-$ branching fraction and effective lifetime and search for $B^0\to\mu^+\mu^-$ decays / LHCb Collaboration A search for the rare decays $B^0_s\to\mu^+\mu^-$ and $B^0\to\mu^+\mu^-$ is performed at the LHCb experiment using data collected in $pp$ collisions corresponding to a total integrated luminosity of 4.4 fb$^{-1}$. An excess of $B^0_s\to\mu^+\mu^-$ decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. [...] CERN-EP-2017-041; LHCB-PAPER-2017-001; arXiv:1703.05747.- Geneva : CERN, 2017-05-11 - 11 p. - Published in : Phys. Rev. Lett. 118 (2017) 191801 APS Open Access Article: PDF; Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP; Related supplementary data file(s): ZIP;