1194519 20260601142713.0 oai:cds.cern.ch:1194519 cerncds:FULLTEXT cerncds:cms-pas Inspire 925349 CMS-PAS-TOP-09-003 CMS Collaboration Prospects for the first Measurement of the ttbar Cross Section in the Muon plus Jets Channel at sqrt(s)=10 TeV with the CMS Detector 2009 Geneva CERN 2009/07/07 A feasibility study is presented of the first measurement of the $t\bar{t}$ pair production cross section in the muon-plus-jets channel at a center-of-mass energy of 10 TeV, using the CMS detector at the LHC. Events are selected which contain one highly energetic muon and at least four jets. Several techniques are used to identify the three jets originating from the hadronic top decay. The \ttbar cross section is extracted by means of template fits to discriminating distributions. The amount of QCD background is determined in a data-driven way using two complementary approaches. Statistical and systematical uncertainties are evaluated using ensemble tests. With $20\rm\ pb^{-1}$ of data, the \ttbar pair production cross section in the muon plus jets channel is expected to be measurable with 12-18\% statistical and 20-25\% systematic error, where the latter is dominated by the jet energy scale uncertainty. CC-BY-4.0 Preprint Particle Physics - Experiment SzGeCERN NOTE CERN CERN LHC CMS CMS Collaboration https://cmsfence.cern.ch/alcm/cmsanalysis/details/ancode=TOP-09-003 Additional information for the analysis (restricted access) http://cds.cern.ch/record/1194519/files/Figure_001-a.pdf Figure_001-a Figure http://cds.cern.ch/record/1194519/files/Figure_001-b.pdf Figure_001-b Figure http://cds.cern.ch/record/1194519/files/Figure_002-a.pdf Figure_002-a Figure http://cds.cern.ch/record/1194519/files/Figure_002-b.pdf Figure_002-b Figure http://cds.cern.ch/record/1194519/files/Figure_002-c.pdf Figure_002-c Figure http://cds.cern.ch/record/1194519/files/Figure_002-d.pdf Figure_002-d Figure http://cds.cern.ch/record/1194519/files/Figure_002-e.pdf Figure_002-e Figure http://cds.cern.ch/record/1194519/files/Figure_002-f.pdf Figure_002-f Figure http://cds.cern.ch/record/1194519/files/Figure_003.pdf Figure_003 Figure http://cds.cern.ch/record/1194519/files/Figure_004.pdf Figure_004 Figure http://cds.cern.ch/record/1194519/files/Figure_005-a.pdf Figure_005-a Figure http://cds.cern.ch/record/1194519/files/Figure_005-b.pdf Figure_005-b Figure http://cds.cern.ch/record/1194519/files/Figure_006-a.pdf Figure_006-a Figure http://cds.cern.ch/record/1194519/files/Figure_006-b.pdf Figure_006-b Figure http://cds.cern.ch/record/1194519/files/Figure_007.pdf Figure_007 Figure http://cds.cern.ch/record/1194519/files/Figure_008-a.pdf Figure_008-a Figure http://cds.cern.ch/record/1194519/files/Figure_008-b.pdf Figure_008-b Figure http://cds.cern.ch/record/1194519/files/Figure_009-a.pdf Figure_009-a Figure http://cds.cern.ch/record/1194519/files/Figure_009-b.pdf Figure_009-b Figure http://cds.cern.ch/record/1194519/files/Figure_009-c.pdf Figure_009-c Figure http://cds.cern.ch/record/1194519/files/Figure_010.pdf Figure_010 Figure http://cds.cern.ch/record/1194519/files/Figure_011-a.pdf Figure_011-a Figure http://cds.cern.ch/record/1194519/files/Figure_011-b.pdf Figure_011-b Figure http://cds.cern.ch/record/1194519/files/Figure_012-a.pdf Figure_012-a Figure http://cds.cern.ch/record/1194519/files/Figure_012-b.pdf Figure_012-b Figure http://cds.cern.ch/record/1194519/files/Figure_012-c.pdf Figure_012-c Figure http://cds.cern.ch/record/1194519/files/Figure_012-d.pdf Figure_012-d Figure http://cds.cern.ch/record/1194519/files/TOP-09-003-pas.pdf Fulltext in PDF cms-pag-conveners-top@cern.ch CMS-PHYSICS-ANALYSIS-SUMMARIES NOTE 1194518 20260601142712.0 oai:cds.cern.ch:1194518 cerncds:FULLTEXT cerncds:cms-pas Inspire 925350 CMS-PAS-TOP-09-002 CMS Collaboration Expectations for observation of top quark pair production in the dilepton final state with the early CMS data at sqrt s = 10 TeV Geneva CERN Expectations for the observation of top-quark pair production in proton-proton collisions at the \lhcE{10} with two leptons (electron or muon) in the final state are presented. The emphasis is put on an analysis strategy for the early phase of CMS operation with data corresponding to an integrated luminosity of $10 \pbinv$. The Standard Model signal and background sources are surveyed for a selection based on the requirement of two leptons (electron or muon) in the final state, at least two hadronic jets and missing transverse energy. A clear signal stands out, and the signal cross section can be measured with a statistical uncertainty of about $15\%$ and a systematic uncertainty close to $10\%$ excluding the uncertainty on the integrated luminosity, which is expected to be $10\%$. A complementary approach is also presented for the early phase of operation which relies on jets reconstructed in the tracker and does not make use of the missing transverse energy observable. A good signal sensitivity can be obtained with such a selection which relies minimally on the calorimeter measurements. Having established simple and robust analysis strategies for the early phase, the possibility to further gain in sensitivity by exploiting the $b$-quark content of the events is studied for an integrated luminosity of $100\pbinv$. CC-BY-4.0 Preprint Particle Physics - Experiment SzGeCERN NOTE CERN CERN LHC CMS CMS Collaboration https://cmsfence.cern.ch/alcm/cmsanalysis/details/ancode=TOP-09-002 Additional information for the analysis (restricted access) http://cds.cern.ch/record/1194518/files/Figure_001.pdf Figure_001 Figure http://cds.cern.ch/record/1194518/files/Figure_002.pdf Figure_002 Figure http://cds.cern.ch/record/1194518/files/Figure_003.pdf Figure_003 Figure http://cds.cern.ch/record/1194518/files/Figure_004-a.pdf Figure_004-a Figure http://cds.cern.ch/record/1194518/files/Figure_004-b.pdf Figure_004-b Figure http://cds.cern.ch/record/1194518/files/Figure_004-c.pdf Figure_004-c Figure http://cds.cern.ch/record/1194518/files/Figure_004-d.pdf Figure_004-d Figure http://cds.cern.ch/record/1194518/files/Figure_005-a.pdf Figure_005-a Figure http://cds.cern.ch/record/1194518/files/Figure_005-b.pdf Figure_005-b Figure http://cds.cern.ch/record/1194518/files/Figure_005-c.pdf Figure_005-c Figure http://cds.cern.ch/record/1194518/files/Figure_006-a.pdf Figure_006-a Figure http://cds.cern.ch/record/1194518/files/Figure_006-b.pdf Figure_006-b Figure http://cds.cern.ch/record/1194518/files/Figure_006-c.pdf Figure_006-c Figure http://cds.cern.ch/record/1194518/files/Figure_007-a.pdf Figure_007-a Figure http://cds.cern.ch/record/1194518/files/Figure_007-b.pdf Figure_007-b Figure http://cds.cern.ch/record/1194518/files/Figure_007-c.pdf Figure_007-c Figure http://cds.cern.ch/record/1194518/files/TOP-09-002-pas.pdf Fulltext in PDF cms-pag-conveners-top@cern.ch CMS-PHYSICS-ANALYSIS-SUMMARIES NOTE 1368889 20260603133537.0 oai:cds.cern.ch:1368889 cerncds:FULLTEXT eng COUNCIL-2979 CERN/2979 20110623 159th Session of Council 159 CERN, Geneva, Switzerland 23 - 24 Jun 2011 2011 cern20110623 CH 20110624 List of Participants Liste des participants Titre français 2011 2011-06-23 CC BY NC-ND 4.0 https://creativecommons.org/licenses/by-nc-nd/4.0/ CERN claudia.passeri@cern.ch http://cds.cern.ch/record/1368889/files/c-2979-LPRSjuin2011.pdf English COUNCIL 1368872 20180611151401.0 oai:cds.cern.ch:1368872 cerncds:FULLTEXT cerncds:lhcb-conf Inspire 1258244 LHCb-CONF-2011-042 eng CERN-LHCb-CONF-2011-042 The LHCb Collaboration Charmless charged two-body $B$ decays at LHCb with 2011 data 2011 CERN Geneva 20 Jul 2011 vincenzo.vagnoni@bo.infn.it 31 p LHCb-ANA-2011-060 Using an integrated luminosity of 320 $\mathrm{pb}^{-1}$ collected by LHCb in the first part of the 2011 run, we reconstruct a large sample of the charmless charged two-body decay modes of $B$ hadrons, providing measurements of the direct $CP$ asymmetries $A_{CP}(B^0 \rightarrow K\pi)=-0.088 \pm 0.011\mathrm{(stat)} \pm 0.008\mathrm{(syst)}$ and $A_{CP}(B^0_s \rightarrow \pi K)=0.27 \pm 0.08\mathrm{(stat)} \pm 0.02\mathrm{(syst)}$. The former constitutes the best measurement in the world as well as the first observation of $CP$ violation at LHCb, while the latter is the first evidence of $CP$ violation in the $B^0_s \rightarrow \pi K$ decay. Furthermore, we measure the branching fractions $\mathcal{BR}(B^0 \rightarrow K^+K^-)=(0.13 ^{+0.06}_{-0.05} \mathrm{(stat)} \pm 0.07\mathrm{(syst)})\times10^{-6}$ and $\mathcal{BR}(B^0_s \rightarrow \pi^+\pi^-)=(0.98 ^{+0.23}_{-0.19} \mathrm{(stat)} \pm 0.11\mathrm{(syst)})\times10^{-6}$. In particular, the absence of a $B^0_s \rightarrow \pi^+\pi^- $ signal is rejected with a statistical significance of 5.3$\sigma$. CC-BY-4.0 Preprint CERN EDS SzGeCERN Particle Physics - Experiment SzGeCERN PHYS Flavour Physics CERN B physics CERN CP violation CERN Branching fraction CERN Rare decays CERN CERN INTNOTE PUBLLHCB INTNOTELHCBCONFPUBL CERN LHC LHCb PH-EP LHCb Collaboration Superseded by LHCB-PAPER-2011-029 1427771 http://cds.cern.ch/record/1368872/files/CONF-2011-042-Figs.zip http://cds.cern.ch/record/1368872/files/LHCb-CONF-2011-042.pdf elodie.beaumont@cern.ch public n 201230 1233501 grenoble20110721 PUBLIC 000715993CER INTNOTELHCBCONFPUBL NOTE ConferencePaper 1368868 SzGeCERN 20170919193930.0 arXiv oai:arXiv.org:1107.3550 Inspire 919228 arXiv:1107.3550 eng Joyce, Austin Strong Coupling Problem with Time-Varying Sound Speed 2011 19 Jul 2011 Comments: 22 pages, 1 figure For a single scalar field with unit sound speed, there are exactly three distinct cosmological solutions which produce a scale invariant spectrum of curvature perturbations in a dynamical attractor background, assuming vacuum initial conditions: slow-roll inflation; a slowly contracting adiabatic ekpyrotic phase, described by a rapidly-varying equation of state; and an adiabatic ekpyrotic phase on a slowly expanding background. Of these three, only inflation remains weakly coupled over a wide range of modes, while the other scenarios can produce at most 12 e-folds of scale invariant and gaussian modes. In this paper, we investigate how allowing the speed of sound of fluctuations to evolve in time affects this classification. While in the presence of a variable sound speed there are many more scenarios which are scale invariant at the level of the two-point function, they generically suffer from strong coupling problems similar to those in the canonical case. There is, however, an exceptional case with superluminal sound speed, which suppresses non-gaussianities and somewhat alleviates strong coupling issues. We show that even these scenarios are constrained and only able to produce at most 28 e-folds of scale invariant and gaussian perturbations. This condition results from the combined requirements of matching the observed amplitude of curvature perturbations, demanding that the Hubble parameter remain sub-Planckian, and keeping non-gaussianities under control. We therefore conclude that inflation remains the unique cosmological scenario, assuming a single degree of freedom on an attractor background, capable of producing arbitrarily many scale invariant modes while remaining weakly coupled. Alternative mechanisms must inevitably be unstable or rely on multiple degrees of freedom. LANL EDS Particle Physics - Theory arXiv PREPRINT hep-th LANL EDS Khoury, Justin http://arxiv.org/pdf/1107.3550.pdf Preprint n 201129 11 PREPRINT Hidden 1368867 SzGeCERN 20170909234244.0 arXiv oai:arXiv.org:1107.3549 arXiv:1107.3549 eng Mahnkopf, Joachim On Truncation of irreducible representations of Chevalley groups 2011 19 Jul 2011 We prove part of a higher rank analogue of the Mazur-Gouvea Conjecture. More precisely, let $\tilde{\bf G}$ be a connected, reductive ${\Bbb Q}$-split group and let $\Gamma$ be an arithmetic subgroup of $\tilde{\bf G}$. We show that the dimension of the slope $\alpha$ subspace of the cohomology of $\Gamma$ with values in an irreducible $\tilde{\bf G}$-module $L$ is bounded independently of $L$. The proof is elementary making only use of general principles of the representation theory of algebraic groups; it is based on consideration of certain truncations of irreducible representations of Chevalley groups. LANL EDS Mathematical Physics and Mathematics arXiv PREPRINT math.NT LANL EDS http://arxiv.org/pdf/1107.3549.pdf Preprint n 201129 11 PREPRINT Hidden