Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV

The azimuthal anisotropy of charged particles in PbPb collisions at nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (pt) range up to approximately 60 GeV. The data cover both the low-pt region associated with hydrodynamic flow phenomena and the high-pt region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter (v2) of the particles is extracted by correlating charged tracks with respect to the event-plane reconstructed by using the energy deposited in forward-angle calorimeters. For the six bins of collision centrality studied, spanning the range of 0-60% most-central events, the observed v2 values are found to first increase with pt, reaching a maximum around pt = 3 GeV, and then to gradually decrease to almost zero, with the decline persisting up to at least pt = 40 GeV over the full centrality range measured.Comment: Replaced with published version. Added journal reference and DO

Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy

A search for new physics is performed in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state. The analysis is based on a data sample corresponding to an integrated luminosity of 4.98 inverse femtobarns produced in pp collisions at a center-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. This constitutes a factor of 140 increase in integrated luminosity over previously published results. The observed yields agree with the standard model predictions and thus no evidence for new physics is found. The observations are used to set upper limits on possible new physics contributions and to constrain supersymmetric models. To facilitate the interpretation of the data in a broader range of new physics scenarios, information on the event selection, detector response, and efficiencies is provided.Comment: Published in Physical Review Letter

Compressed representation of a partially defined integer function over multiple arguments

In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one

Measurement of jet fragmentation into charged particles in pp and PbPb collisions at sqrt(s[NN]) = 2.76 TeV

Jet fragmentation in pp and PbPb collisions at a centre-of-mass energy of 2.76 TeV per nucleon pair was studied using data collected with the CMS detector at the LHC. Fragmentation functions are constructed using charged-particle tracks with transverse momenta pt > 4 GeV for dijet events with a leading jet of pt > 100 GeV. The fragmentation functions in PbPb events are compared to those in pp data as a function of collision centrality, as well as dijet-pt imbalance. Special emphasis is placed on the most central PbPb events including dijets with unbalanced momentum, indicative of energy loss of the hard scattered parent partons. The fragmentation patterns for both the leading and subleading jets in PbPb collisions agree with those seen in pp data at 2.76 TeV. The results provide evidence that, despite the large parton energy loss observed in PbPb collisions, the partition of the remaining momentum within the jet cone into high-pt particles is not strongly modified in comparison to that observed for jets in vacuum.Comment: Submitted to the Journal of High Energy Physic

Short and long term effects of a lifestyle intervention for construction workers at risk for cardiovascular disease: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>The prevalence of overweight and elevated cardiovascular disease (CVD) risk among workers in the construction industry is relatively high. Improving lifestyle lowers CVD risk and may have work-related benefits. The purpose of the study was to evaluate the effects on physical activity (PA), diet, and smoking of a lifestyle intervention consisting of individual counseling among male workers in the construction industry with an elevated risk of cardiovascular disease (CVD).</p> <p>Methods</p> <p>In a randomized controlled trial including 816 male blue- and white-collar workers in the construction industry with an elevated risk of CVD, usual care was compared to a 6-month lifestyle intervention. The intervention consisted of individual counseling using motivational interviewing techniques, and was delivered by an occupational physician or occupational nurse. In three face to face and four telephone contacts, the participant's risk profile, personal determinants, and barriers for behavior change were discussed, and personal goals were set. Participants chose to aim at either diet and PA, or smoking. Data were collected at baseline and after six and 12 months, by means of a questionnaire. To analyse the data, linear and logistic regression analyses were performed.</p> <p>Results</p> <p>The intervention had a statistically significant beneficial effect on snack intake (β-1.9, 95%CI -3.7; -0.02) and fruit intake (β 1.7, 95%CI 0.6; 2.9) at 6 months. The effect on snack intake was sustained until 12 months; 6 months after the intervention had ended (β -1.9, 95%CI -3.6; -0.2). The intervention effects on leisure time PA and metabolic equivalent-minutes were not statistically significant. The beneficial effect on smoking was statistically significant at 6 (OR smoking 0.3, 95%CI 0.1;0.7), but not at 12 months (OR 0.8, 95%CI 0.4; 1.6).</p> <p>Conclusions</p> <p>Beneficial effects on smoking, fruit, and snack intake can be achieved by an individual-based lifestyle intervention among male construction workers with an elevated risk of CVD. Future research should be done on strategies to improve leisure time PA and on determinants of maintenance of changed behavior. Considering the rising prevalence of unhealthy lifestyle and CVD, especially in the aging population, implementation of this intervention in the occupational health care setting is recommended.</p> <p>Trial registration</p> <p>Current Controlled Trials <a href="http://www.controlled-trials.com/ISRCTN60545588">ISRCTN60545588</a></p

Evaluation of the implementation of an integrated primary care network for prevention and management of cardiometabolic risk in Montréal

<p>Abstract</p> <p>Background</p> <p>The goal of this project is to evaluate the implementation of an integrated and interdisciplinary program for prevention and management of cardiometabolic risk (PCMR). The intervention is based on the Chronic Care Model. The study will evaluate the implementation of the PCMR in 6 of the 12 health and social services centres (CSSS) in Montréal, and the effects of the PCMR on patients and the practice of their primary care physicians up to 40 months following implementation, as well as the sustainability of the program. Objectives are: 1-to evaluate the effects of the PCMR and their persistence on patients registered in the program and the practice of their primary care physicians, by implementation site and degree of exposure to the program; 2-to assess the degree of implementation of PCMR in each CSSS territory and identify related contextual factors; 3-to establish the relationships between the effects observed, the degree of PCMR implementation and the related contextual factors; 4-to assess the impact of the PCMR on strengthening local services networks.</p> <p>Methods/Design</p> <p>The evaluation will use a mixed design that includes two complementary research strategies. The first strategy is similar to a quasi-experimental "before-after" design, based on a quantitative approach; it will look at the program's effects and their variations among the six territories. The effects analysis will use data from a clinical database and from questionnaires completed by participating patients and physicians. Over 3000 patients will be recruited. The second strategy corresponds to a multiple case study approach, where each of the six CSSS constitutes a case. With this strategy, qualitative methods will set out the context of implementation using data from semi-structured interviews with program managers. The quantitative data will be analyzed using linear or multilevel models complemented with an interpretive approach to qualitative data analysis.</p> <p>Discussion</p> <p>Our study will identify contextual factors associated with the effectiveness, successful implementation and sustainability of such a program. The contextual information will enable us to extrapolate our results to other contexts with similar conditions.</p> <p>Trial registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01326130">NCT01326130</a></p

Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions

Peer reviewe