# EP Articles

Najnovije dodano:
2019-07-18
17:03
 Precision measurement of the $\Lambda_c^+$, $\Xi_c^+$ and $\Xi_c^0$ baryon lifetimes / LHCb Collaboration We report measurements of the lifetimes of the $\Lambda_c^+$, $\Xi_c^+$ and $\Xi_c^0$ charm baryons using proton-proton collision data at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3.0 fb$^{-1}$, collected by the LHCb experiment. The charm baryons are reconstructed through the decays $\Lambda_c^+\to pK^-\pi^+$, $\Xi_c^+\to pK^-\pi^+$ and $\Xi_c^0\to pK^-K^-\pi^+$, and originate from semimuonic decays of beauty baryons. [...] arXiv:1906.08350; LHCb-PAPER-2019-008; CERN-EP-2019-122; LHCB-PAPER-2019-008.- 2019-08-02 - 12 p. - Published in : Phys. Rev. D 100 (2019) 032001 Article from SCOAP3: PDF; Fulltext: PDF; Related data file(s): ZIP; Supplementary information: ZIP;

2019-06-21
17:07
 Measurement of $C\!P$ observables in the process $B^0 \to DK^{*0}$ with two- and four-body $D$ decays / LHCb Collaboration Measurements of $C\!P$ observables in $B^0 \to DK^{*0}$ decays are presented, where $D$ represents a superposition of $D^0$ and $\bar{D}^0$ states. The $D$ meson is reconstructed in the two-body final states $K^+\pi^-$, $\pi^+ K^-$, $K^+K^-$ and $\pi^+\pi^-$, and, for the first time, in the four-body final states $K^+\pi^-\pi^+\pi^-$, $\pi^+ K^-\pi^+\pi^-$ and $\pi^+\pi^-\pi^+\pi^-$. [...] arXiv:1906.08297; LHCb-PAPER-2019-021; CERN-EP-2019-111.- Geneva : CERN, 2019-08-07 - 30 p. - Published in : JHEP 1908 (2019) 041 Fulltext: LHCb-PAPER-2019-021 - PDF; 1906.08297 - PDF; Related data file(s): ZIP; Supplementary information: ZIP;

2019-05-16
14:53
 Amplitude analysis of the $B^0_{(s)} \to K^{*0} \overline{K}^{*0}$ decays and measurement of the branching fraction of the $B^0 \to K^{*0} \overline{K}^{*0}$ decay / LHCb Collaboration The $B^0 \to K^{*0} \overline{K}^{*0}$ and $B^0_s \to K^{*0} \overline{K}^{*0}$ decays are studied using proton-proton collision data corresponding to an integrated luminosity of 3fb$^{-1}$. An untagged and time-integrated amplitude analysis of $B^0_{(s)} \to (K^+\pi^-)(K^-\pi^+)$ decays in two-body invariant mass regions of 150 MeV$/c^2$ around the $K^{*0}$ mass is performed. [...] arXiv:1905.06662; LHCb-PAPER-2019-004; CERN-EP-2019-063; LHCB-PAPER-2019-004.- Geneva : CERN, 2019-07-05 - 30 p. - Published in : JHEP 1907 (2019) 032 Article from SCOAP3: PDF; Fulltext: LHCb-PAPER-2019-004 - PDF; 1905.06662 - PDF; Related data file(s): ZIP;

2019-04-10
11:16
 Observation of a narrow pentaquark state, $P_c(4312)^+$, and of two-peak structure of the $P_c(4450)^+$ / LHCb Collaboration A narrow pentaquark state, $P_c(4312)^+$, decaying to $J/\psi p$ is discovered with a statistical significance of $7.3\sigma$ in a data sample of $\Lambda_b^0\to J/\psi p K^-$ decays which is an order of magnitude larger than that previously analyzed by the LHCb collaboration. The $P_c(4450)^+$ pentaquark structure formerly reported by LHCb is confirmed and observed to consist of two narrow overlapping peaks, $P_c(4440)^+$ and $P_c(4457)^+$, where the statistical significance of this two-peak interpretation is $5.4\sigma$. [...] arXiv:1904.03947; LHCb-PAPER-2019-014 CERN-EP-2019-058; LHCB-PAPER-2019-014.- Geneva : CERN, 2019-06-06 - 11 p. - Published in : Phys. Rev. Lett. 122 (2019) 222001 Article from SCOAP3: PDF; Fulltext: PDF; Fulltext from Publisher: PDF; Related data file(s): ZIP; Supplementary information: ZIP; External link: SYMMETRY

2019-04-01
11:42
 Observation of an excited $B_c^+$ state / LHCb Collaboration Using $pp$ collision data corresponding to an integrated luminosity of $8.5\,\mathrm{fb}^{-1}$ recorded by the LHCb experiment at centre-of-mass energies of $\sqrt{s} = 7$, $8$ and $13\mathrm{\,Te\kern -0.1em V}$, the observation of an excited $B_c^+$ state in the $B_c^+\pi^+\pi^-$ invariant-mass spectrum is reported. The state has a mass of $6841.2 \pm 0.6 {\,\rm (stat)\,} \pm 0.1 {\,\rm (syst)\,} \pm 0.8\,(B_c^+) \mathrm{\,MeV}/c^2$, where the last uncertainty is due to the limited knowledge of the $B_c^+$ mass. [...] arXiv:1904.00081; CERN-EP-2019-050; LHCb-PAPER-2019-007.- Geneva : CERN, 2019-06-11 - 10 p. - Published in : Phys. Rev. Lett. 122 (2019) 232001 Article from SCOAP3: PDF; Fulltext: PDF; Fulltext from Publisher: PDF; Related data file(s): ZIP; Supplementary information: ZIP;

2019-04-01
09:46
 Near-threshold $D\bar{D}$ spectroscopy and observation of a new charmonium state / LHCb Collaboration Using proton-proton collisiondata, corresponding to an integrated luminosity of 9 fb$^{-1}$, collected with the~LHCb detector between 2011 and 2018, a new narrow charmonium state, the $X(3842)$ resonance, is observed in the decay modes $X(3842)\rightarrow D^0\bar{D}^0$ and $X(3842)\rightarrow D^+D^-$. The mass and the natural width of this state are measured to be \begin{eqnarray*} m_{X(3842)} & = & 3842.71 \pm 0.16 \pm 0.12~ \text {MeV}/c^2\,, \\ \Gamma_{X(3842)} & = & 2.79 \pm 0.51 \pm 0.35 ~ \text {MeV}\,, \end{eqnarray*} where the first uncertainty is statistical and the second is systematic. [...] arXiv:1903.12240; CERN-EP-2019-047; LHCb-PAPER-2019-005; LHCB-PAPER-2019-005.- Geneva : CERN, 2019-07-08 - 23 p. - Published in : JHEP 1907 (2019) 035 Article from SCOAP3: PDF; Fulltext: PDF; Related data file(s): ZIP; Supplementary information: ZIP;

2019-03-22
09:21
 Search for lepton-universality violation in $B^+\to K^+\ell^+\ell^-$ decays / LHCb Collaboration A measurement of the ratio of branching fractions of the decays $B^+\to K^+\mu^+\mu^-$ and $B^+\to K^+e^+e^-$ is presented. The proton-proton collision data used correspond to an integrated luminosity of $5.0$ fb$^{-1}$ recorded with the LHCb experiment at centre-of-mass energies of $7$, $8$ and $13$ TeV. [...] arXiv:1903.09252; LHCb-PAPER-2019-009; CERN-EP-2019-043; LHCb-PAPER-2019-009 CERN-EP-2019-043.- Geneva : CERN, 2019-05-14 - 13 p. - Published in : Phys. Rev. Lett. 122 (2019) 191801 Article from SCOAP3: PDF; Fulltext: 1903.09252 - PDF; LHCb-PAPER-2019-009 - PDF; Fulltext from Publisher: PDF; Related data file(s): ZIP; Supplementary information: ZIP;

2019-03-21
08:49
 Observation of $C\!P$ violation in charm decays / LHCb Collaboration A search for charge-parity ($C\!P$) violation in $D^0 \to K^- K^+$ and $D^0 \to \pi^- \pi^+$ decays is reported, using $pp$ collision data corresponding to an integrated luminosity of 6 $\mathrm{fb}^{-1}$ collected at a center-of-mass energy of 13 TeV with the LHCb detector. The flavor of the charm meson is inferred from the charge of the pion in $D^*(2010)^+ \to D^0 \pi^+$ decays or from the charge of the muon in $\overline{B} \to D^0 \mu^-\bar{\nu}_\mu X$ decays. [...] arXiv:1903.08726; LHCb-PAPER-2019-006; CERN-EP-2019-042; LHCB-PAPER-2019-006.- Geneva : CERN, 2019-05-29 - 12 p. - Published in : Phys. Rev. Lett. 122 (2019) 211803 Article from SCOAP3: PDF; Fulltext: LHCb-PAPER-2019-006 - PDF; 1903.08726 - PDF; Fulltext from Publisher: PDF; Related data file(s): ZIP; Supplementary information: ZIP; External link: SYMMETRY

2019-03-14
14:52
 Measurement of the $CP$-violating phase $\phi_s$ from $B_{s}^{0}\to J/\psi\pi^+\pi^-$ decays in 13 TeV $pp$ collisions / LHCb Collaboration Decays of $B_{s}^{0}$ and $\overline{B}{}_{s}^{0}$ mesons into $J/\psi\pi^+\pi^-$ final states are studied in a data sample corresponding to 1.9 fb$^{-1}$ of integrated luminosity collected with the LHCb detector in 13 TeV $pp$ collisions. A time-dependent amplitude analysis is used to determine the final-state resonance contributions, the $CP$-violating phase $\phi_s=-0.057\pm 0.060\pm 0.011$ rad, the decay-width difference between the heavier mass $B_{s}^{0}$ eigenstate and the $B^{0}$ meson of $-0.050\pm 0.004\pm 0.004$ ps$^{-1}$, and the $CP$-violating parameter $|\lambda|=1.01_{-0.06}^{+0.08}\pm0.03$, where the first uncertainty is statistical and the second systematic. [...] arXiv:1903.05530; LHCb-PAPER-2019-003; CERN-EP-2019-037; CERN-EP-2019-037; LHCb-PAPER-2019-003; LHCB-PAPER-2019-003.- 2019-10-10 - 24 p. - Published in : Phys. Lett. B 797 (2019) 134789 Article from SCOAP3: PDF; Fulltext: PDF; Related data file(s): ZIP;

2019-03-08
09:57
 Measurement of the mass difference between neutral charm-meson eigenstates / LHCb Collaboration We report a measurement of the mass difference between neutral charm-meson eigenstates using a novel approach that enhances sensitivity to this parameter. We use $2.3\times10^6$ $D^0\to K_S^0\pi^+\pi^-$ decays reconstructed in proton-proton collisions collected by the LHCb experiment in 2011 and 2012. [...] arXiv:1903.03074; CERN-EP-2019-032; LHCb-PAPER-2019-001.- Geneva : CERN, 2019-06-14 - 10 p. - Published in : Phys. Rev. Lett. 122 (2019) 231802 Article from SCOAP3: PDF; Fulltext: PDF; Fulltext from Publisher: PDF; Related data file(s): ZIP; Supplementary information: ZIP;