5543619
Tracking and Alignment in the CMS Detector
This Report summarises the alignment strategy of the CMS detector. Track reconstruction in the silicon tracker and muon chambers is briefly described. We then present the different sources of alignment information, in particular alignment algorithms using reconstructed tracks.
209834639
Search for supersymmetry in events with b-quark jets and missing transverse energy in pp collisions at 7 TeV
Results are presented from a search for physics beyond the standard model based on events with large missing transverse energy, at least three jets, and at least one, two, or three b-quark jets. The study is performed using a sample of proton-proton collision data collected at sqrt(s)=7 TeV with the CMS detector at the LHC in 2011, with the missing transverse energy distribution as the principal search variable. The integrated luminosity of the sample is 4.98 inverse femtobarns. The observed number of events is found to be consistent with the standard model expectation, which is evaluated using control samples in the data. The results are used to constrain cross sections for the production of supersymmetric particles decaying to b-quark-enriched final states in the context of simplified model spectra.
122757815
Performance Study of the CMS Barrel Resistive Plate Chambers with Cosmic Rays
In October and November 2008, the CMS collaboration conducted a programme of cosmic ray data taking, which has recorded about 270 million events. The Resistive Plate Chamber system, which is part of the CMS muon detection system, was successfully operated in the full barrel. More than 98% of the channels were operational during the exercise with typical detection efficiency of 90%. In this paper, the performance of the detector during these dedicated runs is reported.
118843154
Performance and operation of the CMS electromagnetic calorimeter
The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75 848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented.
199676084
Measurement of the differential q**2 spectrum and forward-backward asymmetry for B ---> K* l+ l-
62211675
PAT: The CMS Physics Analysis Toolkit
The CMS Physics Analysis Toolkit (PAT) is presented. The PAT is a high-level analysis layer enabling the development of common analysis efforts across and within Physics Analysis Groups. It aims at fulfilling the needs of most CMS analyses, providing both ease-of-use for the beginner and flexibility for the advanced user. The main PAT concepts are described in detail and some examples from physics analyses are given.
115386522
Neutrino produced upward-going muons in the MACRO experiment
207792360
Low energy atmospheric muon neutrinos in MACRO
Abstract We present the measurement of two event samples induced by atmospheric ν μ of average energy E ν ∼4 GeV. In the first sample, a neutrino interacts inside the MACRO detector producing an upward-going muon leaving the apparatus. The ratio of the number of observed to expected events is 0.57±0.05 stat ±0.06 syst ±0.14 theor with an angular distribution similar to that expected from the Bartol atmospheric neutrino flux. The second is a mixed sample of internally produced downward-going muons and externally produced upward-going muons stopping inside the detector. These two subsamples are selected by topological criteria; the lack of timing information makes it impossible to distinguish stopping from downgoing muons. The ratio of the number of observed to expected events is 0.71±0.05 stat ±0.07 syst ±0.18 theor . The observed deficits in each subsample is in agreement with neutrino oscillations, although the significance is reduced by the large theoretical errors. However, the ratio of the two samples causes a large cancellation of theoretical and of some systematic errors. With the ratio, we rule out the no-oscillation hypothesis at 95% c.l. Furthermore, the ratio tests the pathlength dependence of possible oscillations. The data of both samples and their ratio favor maximal mixing and Δm 2 ∼10 −3 –10 −2 eV 2 . These parameters are in agreement with our results from upward throughgoing muons, induced by ν μ of much higher energies.
56260506
Measurement of mechanical vibrations excited in aluminium resonators by 0.6 GeV electrons
We present measurements of mechanical vibrations induced by 0.6 GeV electrons impinging on cylindrical and spherical aluminum resonators. To monitor the amplitude of the resonator’s vibrational modes we used piezoelectric ceramic sensors calibrated by standard accelerometers. Calculations using the thermo-acoustic conversion model agree well with the experimental data, as demonstrated by specific variations of the excitation strengths with the absorbed energy, and with the traversing particles’ track positions. For the first longitudinal mode of the cylindrical resonator we measured a conversion factor of 7.4±1.4 nm/J, confirming the model value of 10 nm/J. Also, for the spherical resonator, we found the model values for the L=2 and L=1 mode amplitudes to be consistent with our measurement. We thus have confirmed the applicability of the model, and we note that calculations based on the model have shown that next generation resonant mass gravitational wave detectors can only be expected to reach their int...
118301834
Multiple Muon Physics With The Macro Detector At Gran Sasso
119382315
Single Muon Physics with the MACRO Detector