# EP Articles

Posledne pridané:
2017-12-22
09:56
 Search for weakly decaying $b$-flavored pentaquarks / LHCb Collaboration Investigations of the existence of pentaquark states containing a single $b$ (anti)quark decaying weakly into four specific final states J/$\psi K^+\pi^- p$, J/$\psi K^- \pi^- p$, J/$\psi K^- \pi^+ p$, and $J/\psi \phi (1020) p$ are reported. The data sample corresponds to an integrated luminosity of 3.0/fb in 7 and 8 TeV pp collisions acquired with the LHCb detector. [...] CERN-EP-2017-329; LHCB-PAPER-2017-043; arXiv:1712.08086; LHCB-PAPER-2017-043.- Geneva : CERN, 2018-02-17 - 11 p. - Published in : Phys. Rev. D 97 (2018) 032010 Article from SCOAP3: PDF; Preprint: PDF; Related data file(s): ZIP;

2017-11-21
11:13
 Search for excited $B_c^+$ states / LHCb Collaboration A search is performed in the invariant mass spectrum of the $B_c^{+}\pi^{+}\pi^{-}$ system for the excited $B_c^{+}$ states $B_c(2^{1}S_{0})^+$ and $B_c(2^{3}S_{1})^+$ using a data sample of $pp$ collisions collected by the LHCb experiment at the centre-of-mass energy of $\sqrt{s} = 8 \,{\mathrm{TeV}}$, corresponding to an integrated luminosity of $2 \,{\mathrm{fb^{-1}}}$. No evidence is seen for either state. [...] CERN-EP-2017-306; LHCB-PAPER-2017-042; arXiv:1712.04094; LHCB-PAPER-2017-042.- Geneva : CERN, 2018-01-29 - 19 p. - Published in : JHEP 01 (2018) 138 Article from SCOAP3: PDF; Preprint: PDF; Supplementary information: ZIP; External link: Additional information for the analysis

2017-11-20
16:12
 Updated determination of $D^0$-$\overline{D}{}^0$ mixing and CP violation parameters with $D^0\to K^+\pi^-$ decays / LHCb Collaboration We report measurements of charm-mixing parameters based on the decay-time-dependent ratio of $D^0\to K^+\pi^-$ to $D^0\to K^-\pi^+$ rates. The analysis uses a data sample of proton-proton collisions corresponding to an integrated luminosity of $5.0$ fb$^{-1}$ recorded by the LHCb experiment from 2011 through 2016. [...] CERN-EP-2017-304; LHCB-PAPER-2017-046; arXiv:1712.03220; LHCB-PAPER-2017-046.- Geneva : CERN, 2018-02-23 - 11 p. - Published in : Phys. Rev. D 97 (2018) 031101 Article from SCOAP3: PDF; Preprint: PDF; Related data file(s): ZIP; Supplementary information: ZIP;

2017-11-20
10:26
 Measurement of branching fractions of charmless four-body $\Lambda_b^0$ and $\Xi_b^0$ decays / LHCb Collaboration A search for charmless four-body decays of $\Lambda_{b}^{0}$ and $\Xi_{b}^{0}$ baryons with a proton and three charged mesons (either kaons or pions) in the final state is performed. The data sample used was recorded in 2011 and 2012 with the LHCb experiment and corresponds to an integrated luminosity of 3 fb$^{-1}$. [...] CERN-EP-2017-278; LHCB-PAPER-2017-034; arXiv:1711.05490; CERN-EP-2017-278-LHCB-PAPER-2017-034; LHCB-PAPER-2017-034.- Geneva : CERN, 2018-02-16 - 25 p. - Published in : JHEP 02 (2018) 098 Article from SCOAP3: PDF; Preprint: PDF; Related data file(s): ZIP;

2017-11-16
09:10
 First observation of $B^{+} \to D_s^{+}K^{+}K^{-}$ decays and a search for $B^{+} \to D_s^{+}\phi$ decays / LHCb Collaboration A search for $B^{+} \to D_s^{+}K^{+}K^{-}$ decays is performed using $pp$ collision data corresponding to an integrated luminosity of 4.8 fb$^{-1}$, collected at centre-of-mass energies of 7, 8 and 13$\,$TeV with the LHCb experiment. A significant signal is observed for the first time and the branching fraction is determined to be \begin{equation*} \mathcal{B}(B^{+} \to D_s^{+}K^{+}K^{-} ) = (7.1 \pm 0.5 \pm 0.6 \pm 0.7) \times 10^{-6}, \end{equation*} where the first uncertainty is statistical, the second systematic and the third due to the uncertainty on the branching fraction of the normalisation mode $B^{+} \to D_s^{+} \overline{\kern -0.2em D}^{0}$. [...] LHCB-PAPER-2017-032; CERN-EP-2017-289; arXiv:1711.05637; LHCB-PAPER-2017-032.- Geneva : CERN, 2018-01-26 - 22 p. - Published in : JHEP 01 (2018) 131 Article from SCOAP3: PDF; Preprint: PDF; Related data file(s): ZIP;

2017-10-17
16:52
 Measurement of the $B^{\pm}$ production cross-section in pp collisions at $\sqrt{s} =$ 7 and 13 TeV / LHCb Collaboration The production of $B^{\pm}$ mesons is studied in $pp$ collisions at centre-of-mass energies of 7 and 13 TeV, using $B^{\pm}\rightarrow J/\psi K^{\pm}$ decays and data samples corresponding to 1.0 fb$^{-1}$ and 0.3 fb$^{-1}$, respectively. The production cross-sections summed over both charges and integrated over the transverse momentum range $0 2017-10-09 10:08  Search for dark photons produced in 13 TeV$pp$collisions / LHCb Collaboration Searches are performed for both prompt-like and long-lived dark photons,$A^{\prime}$, produced in proton-proton collisions at a center-of-mass energy of 13 TeV, using$A^{\prime}\to\mu^+\mu^-$decays and a data sample corresponding to an integrated luminosity of 1.6 fb$^{-1}$collected with the LHCb detector. The prompt-like$A^{\prime}$search covers the mass range from near the dimuon threshold up to 70 GeV, while the long-lived$A^{\prime}$search is restricted to the low-mass region$214

2017-09-18
16:32
 Measurement of $CP$ observables in $B^{\pm} \rightarrow D K^{*\pm}$ decays using two- and four-body $D$ final states / LHCb Collaboration Measurements of $CP$ observables in $B^{\pm} \rightarrow D K^{*\pm}$ decays are presented, where $D$ denotes a superposition of $D^0$ and $\overline{D^0}$ meson states. Decays of the $D$ meson to $K^{-}\pi^{+}$, $K^{-}K^{+}$, $\pi^{-}\pi^{+}$, $K^{-}\pi^{+}\pi^{-}\pi^{+}$ and $\pi^{-}\pi^{+}\pi^{-}\pi^{+}$ are used and the $K^{*\pm}$ meson is reconstructed in the $K^{0}_{\mathrm{S}}\pi^{\pm}$ final state. [...] LHCB-PAPER-2017-030; CERN-EP-2017-208; arXiv:1709.05855; LHCB-PAPER-2017-030.- Geneva : CERN, 2017-11-23 - 27 p. - Published in : JHEP 11 (2017) 156 Article from SCOAP3: PDF; Preprint: PDF; Related data file(s): ZIP;

2017-09-15
14:53
 Precise measurement of the $\chi_{c1}$ and $\chi_{c2}$ resonance parameters with the decays $\chi_{c1,c2}\to J/\psi\mu^+\mu^-$ / LHCb Collaboration The decays $\chi_{c1} \rightarrow J/\psi \mu^+ \mu^-$ and $\chi_{c2} \rightarrow J/\psi \mu^+ \mu^-$ are observed and used to study the resonance parameters of the $\chi_{c1}$ and $\chi_{c2}$ mesons. The masses of these states are measured to be m(\chi_{c1}) = 3510.71 \pm 0.04(stat) \pm 0.09(syst)MeV\,, m(\chi_{c2}) = 3556.10 \pm 0.06(stat) \pm 0.11(syst)MeV\,, where the knowledge of the momentum scale for charged particles dominates the systematic uncertainty. [...] CERN-EP-2017-228; LHCB-PAPER-2017-036; arXiv:1709.04247; LHCB-PAPER-2017-036.- Geneva : CERN, 2017-11-28 - 9 p. - Published in : Phys. Rev. Lett. 119 (2017) 221801 Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP; Supplementary information: ZIP;

2017-09-14
12:21
 Measurement of $CP$ violation in $B^0\rightarrow J/\psi K^0_\mathrm{S}$ and $B^0\rightarrow\psi(2S) K^0_\mathrm{S}$ decays / LHCb Collaboration A measurement is presented of decay-time-dependent $CP$ violation in the decays $B^0\rightarrow J/\psi K^0_\mathrm{S}$ and $B^0\rightarrow\psi(2S) K^0_\mathrm{S}$, where the $J/\psi$ is reconstructed from two electrons and the $\psi(2S)$ from two muons. The analysis uses a sample of $pp$ collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 $\mathrm{fb}^{-1}$. [...] LHCB-PAPER-2017-029; CERN-EP-2017-209; arXiv:1709.03944; LHCB-PAPER-2017-029.- Geneva : CERN, 2017-11-27 - 18 p. - Published in : JHEP 11 (2017) 170 Article from SCOAP3: PDF; Preprint: PDF; Related data file(s): ZIP;