Publications (18)7.37 Total impact
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Article: Measurement of J/Ψ production in pp collisions at TeV
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ABSTRACT: The production of J/yJ\hspace{-1.5pt}/\hspace{-0.45pt}\psi mesons in proton–proton collisions at Ös=7 TeV\sqrt{s}=7\ensuremath {~\mathrm {TeV}} is studied with the LHCb detector at the LHC. The differential cross-section for prompt J/yJ\hspace{-1.5pt}/\hspace{-0.45pt}\psi production is measured as a function of the J/yJ\hspace{-1.5pt}/\hspace{-0.45pt}\psi transverse momentum pT and rapidity y in the fiducial region pT Î [0;14]GeVmu/mu c{\ensuremath{p_{\mathrm{T}}}}\in[0;14]{\ensuremath{~\mathrm{GeV}\mskip-2mu/\mskip-1mu c}} and y∈[2.0;4.5]. The differential cross-section and fraction of J/yJ\hspace{-1.5pt}/\hspace{-0.45pt}\psi from b-hadron decays are also measured in the same pT and y ranges. The analysis is based on a data sample corresponding to an integrated luminosity of 5.2pb−1. The measured cross-sections integrated over the fiducial region are J/y{\ensuremath{J\hspace{-1.5pt}/\hspace{-0.45pt}\psi}} production and J/yJ\hspace{-1.5pt}/\hspace{-0.45pt}\psi from b-hadron decays, where the first uncertainty is statistical and the second systematic. The promptJ/y{\ensuremath{J\hspace{-1.5pt}/\hspace{-0.45pt}\psi}} production cross-section is obtained assuming no J/yJ\hspace{-1.5pt}/\hspace{-0.45pt}\psi polarisation and the third error indicates the acceptance uncertainty due to this assumption.European Physical Journal C 04/2012; 71(5):1-17. · 3.63 Impact Factor -
Article: Search for the rare decays Bs -->mumu and Bd -->mumu
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ABSTRACT: A search for the decays Bs-->mumu and Bd-->mumu is performed with about 37 pb^{-1} of pp collisions at sqrt{s} = 7 TeV collected by the LHCb experiment at the Large Hadron Collider at CERN. The observed numbers of events are consistent with the background expectations. The resulting upper limits on the branching ratios are BR(Bs-->mumu) < 5.6 x 10^{-8} and BR(Bd-->mumu) <1.5 x 10^{-8} at 95% confidence level.03/2011; -
Article: First observation of Bs -> J/psi f0(980) decays
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ABSTRACT: Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the hadronic decay Bs -> J/psi f0(980) is observed. This CP eigenstate mode could be used to measure mixing-induced CP violation in the B_s system. Using a fit to the pi+ pi- mass spectrum with interfering resonances gives R_{f0/phi} = [Gamma(Bs -> J/psi f0, f0 -> pi+ pi-)]/[Gamma(Bs -> J/psi phi, phi -> K+K-)] = 0.252^{+0.046+0.027}_{-0.032-0.033}, where the uncertainties are statistical and systematic, respectively.02/2011; -
Article: First observation of Bs -> D_{s2}^{*+} X mu nu decays
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ABSTRACT: Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays Bs -> Ds+ X mu nu and Bs -> D0 K+ X mu nu are detected. Two structures are observed in the D0 K+ mass spectrum at masses consistent with the known D^+_{s1}(2536) and $D^{*+}_{s2}(2573) mesons. The measured branching fractions relative to the total Bs semileptonic rate are B(Bs -> D_{s2}^{*+} X mu nu)/B(Bs -> X mu nu)= (3.3\pm 1.0\pm 0.4)%, and B(Bs -> D_{s1}^+ X munu)/B(Bs -> X mu nu)= (5.4\pm 1.2\pm 0.5)%, where the first uncertainty is statistical and the second is systematic. This is the first observation of the D_{s2}^{*+} state in Bs decays; we also measure its mass and width.02/2011; -
Article: Prompt K_short production in pp collisions at sqrt(s)=0.9 TeV
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ABSTRACT: The production of K_short mesons in pp collisions at a centre-of-mass energy of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The luminosity of the analysed sample is determined using a novel technique, involving measurements of the beam currents, sizes and positions, and is found to be 6.8 +/- 1.0 microbarn^-1. The differential prompt K_short production cross-section is measured as a function of the K_short transverse momentum and rapidity in the region 0 < pT < 1.6 GeV/c and 2.5 < y < 4.0. The data are found to be in reasonable agreement with previous measurements and generator expectations.08/2010; -
Article: Roadmap for selected key measurements of LHCb
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ABSTRACT: Six of the key physics measurements that will be made by the LHCb experiment, concerning CP asymmetries and rare B decays, are discussed in detail. The "road map" towards the precision measurements is presented, including the use of control channels and other techniques to understand the performance of the detector with the first data from the LHC. Comment: 378 pages; added some references and fixed a few typos12/2009; -
Article: The LHCb Detector at the LHC
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ABSTRACT: The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described.Journal of Instrumentation 08/2008; 3(08):S08005. · 1.87 Impact Factor -
Article: The LHCb Detector at the LHC
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ABSTRACT: The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described.Journal of Instrumentation 08/2008; 3(08):S08005. · 1.87 Impact Factor -
Article: Search for the rare decays $B^{0}_{s} \to \mu^{+} \mu^{-}$ and $B^{0} \to \mu^{+} \mu^{-}$
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ABSTRACT: A search for the decays $B_{s}^{0}\to\mu^+\mu^-$ and $B^{0}\to\mu^+\mu^-$ is performed with about 37 pb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 7 TeV collected by the LHCb experiment at the Large Hadron Collider at CERN. The observed numbers of events are consistent with the background expectations. The resulting upper limits on the branching ratios are $B(B_{s}^{0}\to\mu^+\mu^-) < 5.6 \times 10^{-8}$ and $B(B^{0}\to\mu^+\mu^-) < 1.5 \times 10^{-8}$ at 95% confidence level. -
Article: First observation of $B^{0}_{s} \to J/\psi f_{0}$(980) decays
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ABSTRACT: Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the hadronic decay $B^{0}_{s} \to J/\psi f_{0}$(980) is observed. This CP eigenstate mode could be used to measure mixing-induced CP violation in the $B^0_s$ system. Using a fit to the $\pi^+ \pi^-$ mass spectrum with interfering resonances gives $R_{f_0/\phi} = [\Gamma(B^0 _s -> J/\psi f0, f0 -> \pi+ \pi-)]/[\Gamma(B^0 _s -> J/\psi \phi, \phi -> K+K-)] = 0.252^{+0.046+0.027}_{-0.032-0.033}$, where the uncertainties are statistical and systematic, respectively. -
Article: First observation of $\overline{B}^{0}_{s} \to D^{*+}_{s2}X\mu^{-}\overline{\nu}$ decays
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ABSTRACT: Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays Bs -> Ds+ X mu nu and Bs -> D0 K+ X mu nu are detected. Two structures are observed in the D0 K+ mass spectrum at masses consistent with the known D^+_{s1}(2536) and $D^{*+}_{s2}(2573) mesons. The measured branching fractions relative to the total Bs semileptonic rate are B(Bs -> D_{s2}^{*+} X mu nu)/B(Bs -> X mu nu)= (3.3\pm 1.0\pm 0.4)%, and B(Bs -> D_{s1}^+ X munu)/B(Bs -> X mu nu)= (5.4\pm 1.2\pm 0.5)%, where the first uncertainty is statistical and the second is systematic. This is the first observation of the D_{s2}^{*+} state in Bs decays; we also measure its mass and width. -
Article: Measurement of J/psi production in pp collisions at sqrt(s)=7 TeV
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ABSTRACT: The production of J/psi mesons in proton-proton collisions at sqrt(s)=7 TeV is studied with the LHCb detector at the LHC. The differential cross-section for prompt J/psi production is measured as a function of the J/psi transverse momentum pT and rapidity y in the fiducial region 0 -
Article: Search for the rare decays Bs -->mumu and Bd -->mumu
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ABSTRACT: A search for the decays Bs-->mumu and Bd-->mumu is performed with about 37 pb^{-1} of pp collisions at sqrt{s} = 7 TeV collected by the LHCb experiment at the Large Hadron Collider at CERN. The observed numbers of events are consistent with the background expectations. The resulting upper limits on the branching ratios are BR(Bs-->mumu) < 5.6 x 10^{-8} and BR(Bd-->mumu) <1.5 x 10^{-8} at 95% confidence level. -
Article: Prompt K^0_s production in pp collisions at sqrt(s)=0.9 TeV
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ABSTRACT: The production of K_short mesons in pp collisions at a centre-of-mass energy of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The luminosity of the analysed sample is determined using a novel technique, involving measurements of the beam currents, sizes and positions, and is found to be 6.8 +/- 1.0 microbarn^-1. The differential prompt K_short production cross-section is measured as a function of the K_short transverse momentum and rapidity in the region 0 < pT < 1.6 GeV/c and 2.5 < y < 4.0. The data are found to be in reasonable agreement with previous measurements and generator expectations.Physics Letters B. -
Article: Prompt $K_{S}^{0}$ production in $pp$ collisions at $\sqrt{s}$ = 0.9 TeV
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ABSTRACT: The production of K_short mesons in pp collisions at a centre-of-mass energy of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The luminosity of the analysed sample is determined using a novel technique, involving measurements of the beam currents, sizes and positions, and is found to be 6.8 +/- 1.0 microbarn^-1. The differential prompt K_short production cross-section is measured as a function of the K_short transverse momentum and rapidity in the region 0 < pT < 1.6 GeV/c and 2.5 < y < 4.0. The data are found to be in reasonable agreement with previous measurements and generator expectations. -
Article: The LHCb Detector at the LHC
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Article: Measurement of sigma(pp -> b anti-b X) at \sqrt(s)=7 TeV in the forward region
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ABSTRACT: Decays of b hadrons into final states containing a D0 meson and a muon are used to measure the b anti-b production cross-section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC. In the pseudorapidity interval 2 < eta < 6 and integrated over all transverse momenta we find that the average cross-section to produce b-flavoured or anti-b-flavoured hadrons is (75.3 +/- 5.4 +/- 13.0) microbarns.Physics Letters B. -
Article: Measurement of $J/\psi$ production in $pp$ collisions at $\sqrt{s}$ = 7 TeV
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ABSTRACT: The production of J/psi mesons in proton-proton collisions at sqrt(s)=7 TeV is studied with the LHCb detector at the LHC. The differential cross-section for prompt J/psi production is measured as a function of the J/psi transverse momentum pT and rapidity y in the fiducial region 0<pT<14 GeV/c and 2.0<y<4.5. The differential cross-section and fraction of J/psi from b-hadron decays are also measured in the same pT and y ranges. The analysis is based on a data sample corresponding to an integrated luminosity of 5.2pb-1. The measured cross-sections integrated over the fiducial region are 10.52 +/- 0.04 +/- 1.40 +1.64/-2.20 mub for prompt J/psi production and 1.14 +/- 0.01 +/- 0.16 mub for J/psi from b-hadron decays, where the first uncertainty is statistical and the second systematic. The prompt J/psi production cross-section is obtained assuming no J/psi polarisation and the third error indicates the acceptance uncertainty due to this assumption.
