# LHCb Conference Contributions

Nyeste elementer:
2013-12-22
21:13
 Reference $pp$ cross-sections for $J/\psi$ studies in proton-lead collisions at $\sqrt{s_{NN}} = 5.02$~TeV and comparisons between ALICE and LHCb results /ALICE Collaboration ; LHCb Collaboration The ALICE and LHCb collaborations have studied $J/\psi$ production at forward rapidities in proton-lead collisions at $\sqrt{s}=5.02$~TeV using the dimuon channel. The evaluation of cold nuclear matter effects requires the knowledge of the corresponding $J/\psi$ cross-section in $pp$ collisions at the same centre-of-mass energy and in the same kinematic range. [...] LHCb-CONF-2013-013; CERN-LHCb-CONF-2013-013; ALICE-PUBLIC-2013-002.- Geneva : CERN, 2013 Figures: ZIP; Fulltext: PDF;

2013-07-25
00:31
 Combination of results on the rare decays $B^0_{(s)} \to \mu^+\mu^-$ from the CMS and LHCb experiments /CMS and LHCb Collaborations A combination of results on the rare decays $B^0_s \to \mu^+\mu^-$ and $B^0 \to \mu^+\mu^-$ from the CMS and LHCb experiments is performed. After accounting for known correlations, the average time-integrated branching fraction of the decay $B^0_s \to \mu^+\mu^-$ is determined to be ${\cal B}(B^0_{s} \to \mu^+\mu^-) = (2.9 \pm 0.7) \times 10^{-9}$ where the uncertainties include both statistical and systematic sources.. CMS-PAS-BPH-13-007; LHCb-CONF-2013-012; CERN-LHCb-CONF-2013-012.- Geneva : CERN, 2013 - 6 p. Figure_001-a: PDF; Figure_001-b: PDF; Figure_002-a: PDF; Figure_002-b: PDF; Fulltext (CMS): PDF; Fulltext (LHCb): PDF; Related data file(s): ZIP; In : EPS-HEP 2013 European Physical Society Conference on High Energy Physics, Stockholm, Sweden, 18 - 24 Jul 2013

2013-07-02
16:33
 Updated average $f_s/f_d$ $b$-hadron production fraction ratio for 7 TeV $pp$ collisions /LHCb Collaboration Improved knowledge of the branching fraction of the decay $D_{s}^{-} \to K^{+}K^{-}\pi^{-}$ and of the $B$ meson lifetimes has an impact on the measurement of the ratio of $B^{0}$ and $B_{s}^{0}$ meson production cross-sections, $f_{s}/f_{d}$, measured at LHCb. This note reports a new combination of the LHCb measurements of $f_s/f_d$, resulting in \mbox{$f_{s}/f_{d} = 0.259 \pm 0.015$}.. LHCb-CONF-2013-011; CERN-LHCb-CONF-2013-011.- Geneva : CERN, 2013 - 6 p. Fulltext: PDF; In : EPS-HEP 2013 European Physical Society Conference on High Energy Physics, Stockholm, Sweden, 18 - 24 Jul 2013

2013-06-17
16:17
 Search for the $\Lambda_{b}^{0} \rightarrow \Lambda \eta^{\prime}$ decay at LHCb /LHCb Collaboration A search is performed for the as yet unobserved baryonic $\Lambda_{b}^{0} \rightarrow \Lambda \eta^{\prime}$ decay with a total integrated luminosity of 2 fb$^{-1}$ of 8 TeV data recorded by the LHCb experiment in 2012. The $B^{0} \rightarrow K_{\rm S}^{0} \eta^{\prime}$ decay is used as a control channel, and the relative branching fraction of these two decays is measured. [...] LHCb-CONF-2013-010; CERN-LHCb-CONF-2013-010.- Geneva : CERN, 2013 - 15 p. Fulltext: LHCb-CONF-2013-010 - PDF; final_figs - ZIP; In : EPS-HEP 2013 European Physical Society Conference on High Energy Physics, Stockholm, Sweden, 18 - 24 Jul 2013

2013-06-17
10:55
 $C\!P$ and up-down asymmetries in $B^{\pm}\!\to\! K^{\pm}\pi^{\mp}\pi^{\pm}\gamma$ decays /LHCb Collaboration We present the first study of the flavour-changing neutral-current radiative $B^+\!\to\! K^+\pi^-\pi^+\gamma$ decay at LHCb. More than 8000 signal events are reconstructed and selected using a data sample corresponding to an integrated luminosity of $2\,$fb$^{-1}$, collected in $pp$ collisions at $\sqrt{s} = 8$ TeV in 2012. [...] LHCb-CONF-2013-009; CERN-LHCb-CONF-2013-009.- Geneva : CERN, 2013 - 16 p. Fulltext: LHCb-CONF-FIG-2013-009 - ZIP; LHCb-CONF-2013-009 - PDF; In : EPS-HEP 2013 European Physical Society Conference on High Energy Physics, Stockholm, Sweden, 18 - 24 Jul 2013

2013-04-25
12:00
 Study of the $J/\psi$ production cross-section in proton-lead collisions at $\sqrt{s_{\rm {\small{NN}}}} = 5~\mathrm{TeV}$ /LHCb Collaboration The production of $J/\psi$ mesons is studied in proton-lead collisions with the LHCb detector, at a proton-nucleon centre-of-mass energy $\sqrt{s_{\rm {\small{NN}}}} = 5 \mathrm{TeV}$ The nuclear attenuation factor is determined and results are compared with theoretical predictions. The analysis is based on a data sample corresponding to an integrated luminosity of about $1~\mathrm{nb}^{-1}$.. LHCb-CONF-2013-008; CERN-LHCb-CONF-2013-008.- Geneva : CERN, 2013 - 15 p. Fulltext: LHCb-CONF-2013-008 - PDF; figs - RAR; In : Workshop on proton-nucleus collisions at the LHC, Trento, Italy, 6 - 10 May 2013

2013-04-05
09:50
 Measurement of the cross-section for $Z\rightarrow\mu\mu$ production with 1 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$=7 TeV /LHCb Collaboration A measurement of the cross-section for $Z\rightarrow\mu\mu$ is presented using LHCb data recorded in 2011. The cross-section is measured for muons with a transverse momentum larger than 20 GeV/c in the pseudorapidity range 2.0 < $\eta$ <4.5. [...] LHCb-CONF-2013-007; CERN-LHCb-CONF-2013-007.- Geneva : CERN, 2013 - 22 p. Fulltext: LHCb_CONF_2013_007_Plots - ZIP; LHCb-CONF-2013-007 - PDF; In : 21st International Workshop on Deep-Inelastic Scattering and Related Subjects, Marseilles, Provence, France, 22 - 26 Apr 2013

2013-04-05
09:38
 Improved constraints on $\gamma$ from $B^\pm\to DK^\pm$ decays including first results on 2012 data /LHCb Collaboration Preliminary results for the CKM angle $\gamma$ are presented, from a combination of measurements using $B^\pm\to DK^\pm$ decays, where $D$ denotes an admixture of $D^0$ and $\overline{D}^0$ mesons. Results for the $D$ final states $K^+K^-$, $\pi^+\pi^-$, $K^\pm \pi^\mp$, and $K^\pm \pi^\mp \pi^\pm \pi^\mp$ are based on a dataset corresponding to $1\,{\rm fb}^-1$ of integrated luminosity recorded at $\sqrt{s}=7\,{\rm TeV}$ in 2011. [...] LHCb-CONF-2013-006; CERN-LHCb-CONF-2013-006.- Geneva : CERN, 2013 - 8 p. Fulltext: LHCb-CONF-2013-006_Figures - ZIP; LHCb-CONF-2013-006 - PDF; In : 14th International Conference on B-Physics at Hadron Machines, Bologna, Italy, 8 - 12 Apr 2013

2013-03-19
10:51
 Graphical comparison of the LHCb measurements of $W$ and $Z$ boson production with ATLAS and CMS /LHCb Collaboration Differential production cross-sections for the $W$ boson as a function of the pseudorapidity of the lepton and for the $Z$ boson as a function of the rapidity of the $Z$ boson measured by LHCb are compared graphically to those measured by ATLAS and CMS. A similar comparison is made for the $W$ lepton charge asymmetry as a function of the lepton pseudorapidity for different thresholds on the transverse momentum of the lepton. [...] LHCb-CONF-2013-005; CERN-LHCb-CONF-2013-005.- Geneva : CERN, 2013 - 13 p. Fulltext: LHCb-CONF-2013-005 - PDF; FIG-CONF-2013-005 - ZIP; In : Working Group on Electroweak precision measurements at the LHC, Geneva, Switzerland, 15 - 16 Apr 2013

2013-03-18
09:11
 Model-independent measurement of $CP$ violation parameters in $B^{\pm}\to(K^{0}_{\rm S}h^{+}h^{-})_{D}K^{\pm}$ decays /LHCb Collaboration The following $CP$ violating observables are measured in a model-independent analysis of $B^{\pm}\to(K^{0}_{\rm S}h^{+}h^{-})_{D}K^{\pm}$ (where $h = \pi, K$) decays reconstructed in a data sample corresponding to an integrated luminosity of 2.0~fb$^{-1}$ of $pp$ interactions collected by the LHCb experiment at a centre-of-mass energy of 8~TeV in 2012 \begin{align*} x_+ & = (-8.7 \pm 3.1 \pm 1.6 \pm 0.6) \times 10^{-2}, \\ x_- & = \phantom{-} ( 5.3 \pm 3.2 \pm 0.9 \pm 0.9) \times 10^{-2}, \\ y_+ & = \phantom{-} ( 0.1 \pm 3.6 \pm 1.4 \pm 1.9) \times 10^{-2}, \\ y_- & = \phantom{-} ( 9.9 \pm 3.6 \pm 2.2 \pm 1.6) \times 10^{-2}, \end{align*} where the first uncertainty is statistical, the second arises from systematic effects from the method or detector considerations and the third from external strong-phase measurements used in the fit. These results are combined with those obtained in the equivalent analysis of LHCb data collected in 2011. [...] LHCb-CONF-2013-004; CERN-LHCb-CONF-2013-004.- Geneva : CERN, 2013 - 17 p. Fulltext: LHCb-CONF-2013-004 - PDF; Figs-LHCb-CONF-2013-004 - ZIP; In : 14th International Conference on B-Physics at Hadron Machines, Bologna, Italy, 8 - 12 Apr 2013