Looking for New Physics in b-decays with LHCb

This article is a short and non-exhaustive summary of the prospects to find New Physics with LHCb as was presented at the HCP conference at Toronto on August 26th 2010

Precision Tests of the Electroweak Interactions at LEP/SLC

This paper is an updated version of the invited plenary talk given at the XXII Physics in Collision Conference at Stanford, (June 2002). The measurements performed at LEP and SLC have substantially improved the precision of the tests of the Minimal Standard Model. The precision is such that there is sensitivity to pure weak radiative corrections. This allows to indirectly determine the top mass (\mt=178$\pm$10 GeV), the W-boson mass (\MW=80.368$\pm$0.022 GeV), and to set an upper limit on the Higgs boson mass of 193 GeV at 95% confidence level.Comment: Invited talk at the XXII Physics in Collisions Conference (PIC02), Stanford, Ca, USA, June 2002, 18 pages, LaTeX, 6 eps figure

Status of indirect searches for New Physics with heavy flavour decays after the initial LHC run

We present a status report on the indirect searches for New Physics performed by means of heavy flavour decays. Particular attention is devoted to the recent experimental results in B and charm physics obtained by the LHC experiments. The implications of these results for physics beyond the Standard Model are discussed both in general terms and by means of a few specific examples.Comment: Invited review based on talks presented at the Open Symposium on the European Strategy for Particle Physics (Krakow, Sept. 2012). arXiv admin note: text overlap with arXiv:1302.0661 (v2: few refs. updated

Measurement of the Cross Section Times Branching Ratio of Light Higgs Decays at CLIC

The investigation of the properties of a Higgs boson, especially a test of the predicted linear dependence of the branching ratios on the mass of the final state, is currently one of the most compelling arguments for building a linear collider. We demonstrate that the large Higgs boson production cross section at a 3 TeV CLIC machine allows for a precision measurement of the Higgs branching ratios. The cross section times branching ratio of the decays H \rightarrow b^{-}b, H \rightarrow cc^{-} and H \rightarrow {\mu}{\mu} can be measured with a statistical uncertainty of 0.22%, 3.2% and 15%, respectively.Comment: LCWS 2011 Proceeding

B Physics at LHCb

LHCb is a dedicated detector for b physics at the LHC. In this article we present a concise review of the detector design and performance together with the main physics goals and their relevance for a precise test of the Standard Model and search of New Physics beyond it.Comment: 26 pages, Contribution to "Perspectives on LHC Physics", ed. G.Kane and A.Pierc

Measurement of the forward Z boson production cross-section in pp collisions at s=13\sqrt{s} = 13 TeV

A measurement of the production cross-section of Z bosons in pp collisions at $\sqrt{s} = 13$ TeV is presented using dimuon and dielectron final states in LHCb data. The cross-section is measured for leptons with pseudorapidities in the range $2.0 \eta 4.5$, transverse momenta $p_\text{T} 20$ GeV and dilepton invariant mass in the range $60 m(\ell\ell) 120$ GeV. The integrated cross-section from averaging the two final states is \begin{equation*}\sigma_{\text{Z}}^{\ell\ell} = 194.3 \pm 0.9 \pm 3.3 \pm 7.6\text{ pb,}\end{equation*} where the first uncertainty is statistical, the second is due to systematic effects, and the third is due to the luminosity determination. In addition, differential cross-sections are measured as functions of the Z boson rapidity, transverse momentum and the angular variable $\phi^*_\eta$

Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $\pm$ 0.02 \mbox{fb}^{-1}. The $W$ bosons are reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ denotes muon or electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions

New algorithms for identifying the flavour of B⁰mesons using pions and protons

Two new algorithms for use in the analysis of pp collision are developed to identify the flavour of B0mesons at production using pions and protons from the hadronization process. The algorithms are optimized and calibrated on data, using B0→D-π+ decays from pp collision data collected by LHCb at centre-of-mass energies of 7 and 8 TeV . The tagging power of the new pion algorithm is 60% greater than the previously available one; the algorithm using protons to identify the flavour of a B0meson is the first of its kind.</p

LHCb upgrade software and computing : technical design report

This document reports the Research and Development activities that are carried out in the software and computing domains in view of the upgrade of the LHCb experiment. The implementation of a full software trigger implies major changes in the core software framework, in the event data model, and in the reconstruction algorithms. The increase of the data volumes for both real and simulated datasets requires a corresponding scaling of the distributed computing infrastructure. An implementation plan in both domains is presented, together with a risk assessment analysis