# EP Articles

Posledne pridané:
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-AND-CERN-EP-2017-037; 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; Preprint: PDF; 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 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+→D*-K+π+ 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 center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3  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 Bs0→μ+μ- and B0→μ+μ- 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 Bs0→μ+μ- 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; 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;

2017-03-09
08:59
 Search for the decays $B_s^0\to\tau^+\tau^-$ and $B^0\to\tau^+\tau^-$ / LHCb Collaboration A search for the rare decays $B_s^0\to\tau^+\tau^-$ and $B^0\to\tau^+\tau^-$ is performed using proton$-$proton collision data collected with the LHCb detector. The data sample corresponds to an integrated luminosity of 3fb$^{-1}$ collected in 2011 and 2012. [...] CERN-EP-2017-034; LHCB-PAPER-2017-003; arXiv:1703.02508.- Geneva : CERN, 2017-06-21 - 10 p. - Published in : Phys. Rev. Lett. 118 (2017) 251802 Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP; Related supplementary data file(s): ZIP;

2017-03-01
14:47
 Observation of the decay $\Lambda^0_b \to p K^- \mu^+ \mu^-$ and a search for $C\!P$ violation / LHCb Collaboration A search for CP violation in the decay Λ$_{b}^{0}$  → pK$^{−}$ μ$^{+}$ μ$^{−}$ is presented. This decay is mediated by flavour-changing neutral-current transitions in the Standard Model and is potentially sensitive to new sources of CP violation. [...] LHCB-PAPER-2016-059; CERN-EP-2017-032; arXiv:1703.00256.- Geneva : CERN, 2017-06-21 - 17 p. - Published in : JHEP 1706 (2017) 108 Article from SCOAP3: PDF; Preprint: PDF; Related data file(s): ZIP; Related supplementary data file(s): ZIP;

2017-03-01
12:41
 Neutron capture cross section measurement of $^{238}$U at the n_TOF CERN facility in the energy region from 1 eV to 700 keV / n_TOF Collaboration The aim of this work is to provide a precise and accurate measurement of the $^{238}$U(n,$\gamma$) reaction cross section in the energy region from 1 eV to 700 keV. This reaction is of fundamental importance for the design calculations of nuclear reactors, governing the behaviour of the reactor core. [...] arXiv:1612.00200.- Bologna : Istituto Nazionale di Fisica Nucleare, 2016 - 14 p.

2017-02-23
10:55
 Measurement of the $C\!P$ violation parameter $A_\Gamma$ in $D^0 \to K^+K^-$ and $D^0 \to \pi^+\pi^-$ decays / LHCb Collaboration Asymmetries in the time-dependent rates of D0→K+K- and D0→π+π- decays are measured in a pp collision data sample collected with the LHCb detector during LHC Run 1, corresponding to an integrated luminosity of 3  fb-1. The asymmetries in effective decay widths between D0 and D¯0 decays, sensitive to indirect CP violation, are measured to be AΓ(K+K-)=(-0.30±0.32±0.10)×10-3 and AΓ(π+π-)=(0.46±0.58±0.12)×10-3, where the first uncertainty is statistical and the second systematic. [...] LHCB-PAPER-2016-063; CERN-EP-2017-028; arXiv:1702.06490.- Geneva : CERN, 2017-06-28 - 9 p. - Published in : Phys. Rev. Lett. 118 (2017) 261803 APS Open Access Article: PDF; Fulltext: PDF; Preprint: PDF; Related data file(s): ZIP; Related supplementary data file(s): ZIP;

2017-02-20
09:47
 Test of an additive diquark spectator model for meson-baryon quasi-two-body reactions / Zralek, M (Nijmegen U.) ; Metzger, W J (Nijmegen U.) ; Van de Walle, R T (Nijmegen U.) ; Dionisi, C (CERN) ; Gurtu, A (CERN) ; Mazzucato, M (CERN) ; Foster, B (Oxford U.) /for the Amsterdam-CERN-Nijmegen-Oxford Collaboration 1978 Fulltext: PDF; In : Meeting on Exotic Resonances, Hiroshima, Japan, 1 - 2 Sep 1978, pp.131