The production cross-sections of B mesons are measured in pp collisions at a centre-of-mass energy of 7 TeV, using data collected with the LHCb detector corresponding to a integrated luminosity of 0.36 fb −1 . The B + , B 0 and B 0 s mesons are reconstructed in the exclusive decays B + → J/ψ K + , B 0 → J/ψ K * 0 and B 0 s → J/ψ φ, with J/ψ → µ + µ − , K * 0 → K + π − and φ → K + K − . The differential cross-sections are measured as functions of B meson transverse momentum p T and rapidity y, in the range 0 < p T < 40 GeV/c and 2.0 < y < 4.5. The integrated cross-sections in the same p T and y ranges, including charge-conjugate states, are measured to be σ(pp → B + + X) = 38.9 ± 0.3 (stat.) ± 2.5 (syst.) ± 1.3 (norm.) µb, σ(pp → B 0 + X) = 38.1 ± 0.6 (stat.) ± 3.7 (syst.) ± 4.7 (norm.) µb, σ(pp → B 0 s + X) = 10.5 ± 0.2 (stat.) ± 0.8 (syst.) ± 1.0 (norm.) µb,where the third uncertainty arises from the pre-existing branching fraction measurements.Keywords: Hadron-Hadron Scattering, Heavy quark production 5 Results and conclusion 6The LHCb collaboration 13 IntroductionMeasurements of beauty production in multi-TeV proton-proton (pp) collisions at the LHC provide important tests of quantum chromodynamics. State of the art theoretical predictions are given by the fixed-order plus next-to-leading logarithm (FONLL) approach [1][2][3]. In these calculations, the dominant uncertainties arise from the choice of the renormalisation and factorisation scales, and the assumed b-quark mass [4]. The primary products of bb hadronisation are B + , B 0 , B 0 s and their charge-conjugate states (throughout the paper referred to as B mesons) formed by oneb quark bound to one of the three light quarks (u, d and s). Accurate measurements of the cross-sections probe the validity of the production models. At the LHC, bb production has been studied in inclusive b → J/ψ X decays [5, 6] and semileptonic [7,8] decays. Other measurements, using fully reconstructed B mesons, have also been performed by the LHCb and CMS collaborations [9][10][11][12].In this paper, a measurement of the production cross-sections of B mesons (including their charge-conjugate states) is presented. This study is performed in the transverse momentum range 0 < p T < 40 GeV/c and rapidity range 2.0 < y < 4.5 using data, corresponding to a integrated luminosity of 0.36 fb −1 , collected in pp collisions at centreof-mass energy of 7 TeV by the LHCb experiment. The B mesons are reconstructed in the exclusive decays B + → J/ψ K + , B 0 → J/ψ K * 0 and B 0 s → J/ψ φ, with J/ψ → µ + µ − , K * 0 → K + π − and φ → K + K − .The LHCb detector [13] is a single-arm forward spectrometer covering the pseudorapidity range 2 < η < 5, designed for the study of particles containing b or c quarks. The detector includes a high-precision tracking system consisting of a silicon-strip vertex detector surrounding the pp interaction region, a large-area silicon-strip detector located upstream of a dipole magnet with a bending power of about 4 Tm, and three stations of silicon-st...

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We discuss the decay of B c mesons into two light mesons (π, K ( * ) , η (′) , ρ, ω, φ ). All these decay channels come from a single type of diagram, namely tree annihilation. This allows us to derive extremely simple SU(3) relations among these processes. The size of annihilation contributions is an important issue in B physics, and we provide two different estimates in the case of non-leptonic charmless B c decays, either a comparison with annihilation decays of heavy-light mesons or a perturbative model inspired by QCD factorisation. We finally discuss a possible search for these channels at LHCb.

SimRank is an intuitive and effective measure for link-based similarity that scores similarity between two nodes as the first-meeting probability of two random surfers, based on the random surfer model. However, when a user queries the similarity of a given node-pair based on SimRank, the existing approaches need to compute the similarities of other node-pairs beforehand, which we call an all-pair style. In this paper, we propose a Single-Pair SimRank approach. Without accuracy loss, this approach performs an iterative computation to obtain the similarity of a single node-pair. The time cost of our Single-Pair SimRank is always less than All-Pair SimRank and obviously efficient when we only need to assess similarity of one or a few node-pairs. We confirm the accuracy and efficiency of our approach in extensive experimental studies over synthetic and real datasets. IntroductionThe measure of similarity between objects plays a significant role in many real-world applications, including clustering, classification, information retrieval, and recommendation systems. The current similarity measures can be generalized into two broad categories: content-based similarity measures and link-based similarity measures [14]. The former is based on the content using a vector space model [16], and the latter is based on a link graph in which objects and relationships are modeled as nodes and edges. Examples of link graphs include citations between papers, social relationships in human or web hyperlinks. Effective and efficient similarity measures between objects in a link graph can greatly assist users for searching and analyzing information [20,9,19,6,5,13], in particular when the relationships among objects are complex.Among the link-based similarity measures in the literature, SimRank [9] has attracted a considerable attention due to its intuition and sturdy theoretical foundation. The basic intuition behind SimRank is "two objects are similar if they are referenced by similar

SUMMARYA new probabilistic analytical approach to evaluate seismic system reliability of large lifeline systems is presented in this paper. The algorithm takes the shortest path from the source to the terminal of a node weight or edge weight network as decomposition policy, using the Boolean laws of set operation and probabilistic operation principal, a recursive decomposition process then could be constructed. For a general weight network, the modiÿed Torrieri method (NTR=T method) is introduced to combine with the suggested algorithm. Therefore, the recursive decomposition algorithm may be applied to evaluate the seismic reliability of general lifeline systems. A series of case studies, including a practical district electric power network system and a large urban water supply system, show that the suggested algorithm supplies a useful probabilistic analysis means for the seismic reliability evaluation of large lifeline systems.

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The B 0 s π AE invariant mass distribution is investigated in order to search for possible exotic meson states.The analysis is based on a data sample recorded with the LHCb detector corresponding to 3 fb −1 of pp collision data at ffiffi ffi s p ¼ 7 and 8 TeV. No significant excess is found, and upper limits are set on the production rate of the claimed Xð5568Þ state within the LHCb acceptance. Upper limits are also set as a function of the mass and width of a possible exotic meson decaying to the B 0 s π AE final state. The same limits also apply to a possible exotic meson decaying through the chain B Ã0 s π AE , B Ã0 s → B 0 s γ where the photon is excluded from the reconstructed decays. DOI: 10.1103/PhysRevLett.117.152003 Interest in exotic hadrons has recently intensified, with a wealth of experimental data becoming available [1,2]. All the well-established exotic states contain a heavy quarkantiquark (cc or bb) pair together with additional light particle content. However, the D0 Collaboration has reported evidence [3] of a narrow structure, referred to as the Xð5568Þ, in the B The LHCb detector [6,7] is a single-arm forward spectrometer covering the pseudorapidity range 2 < η < 5, designed for the study of particles containing b or c quarks.

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