9430917
Likelihood functions for supersymmetric observables in frequentist analyses of the CMSSM and NUHM1
On the basis of frequentist analyses of experimental constraints from electroweak precision data, (g−2)μ, B-physics and cosmological data, we investigate the parameters of the constrained MSSM (CMSSM) with universal soft supersymmetry-breaking mass parameters, and a model with common non-universal Higgs masses (NUHM1). We present χ2 likelihood functions for the masses of supersymmetric particles and Higgs bosons, as well as BR(b→sγ), BR(Bs→μ+μ−) and the spin-independent dark-matter scattering cross section, σpSI. In the CMSSM we find preferences for sparticle masses that are relatively light. In the NUHM1 the best-fit values for many sparticle masses are even slightly smaller, but with greater uncertainties. The likelihood functions for most sparticle masses are cut off sharply at small masses, in particular by the LEP Higgs mass constraint. Both in the CMSSM and the NUHM1, the coannihilation region is favored over the focus-point region at about the 3-σ level, largely but not exclusively because of (g−2)μ. Many sparticle masses are highly correlated in both the CMSSM and NUHM1, and most of the regions preferred at the 95% C.L. are accessible to early LHC running, though high-luminosity running would be needed to cover the regions allowed at the 3-σ levels. Some slepton and chargino/neutralino masses should be in reach at the ILC. The masses of the heavier Higgs bosons should be accessible at the LHC and the ILC in portions of the preferred regions in the (MA,tan β) plane. In the CMSSM, the likelihood function for BR(Bs→μ+μ−) is peaked close to the Standard Model value, but much larger values are possible in the NUHM1. We find that values of σpSI>10−10 pb are preferred in both the CMSSM and the NUHM1. We study the effects of dropping the (g−2)μ, BR(b→sγ), Ωχh2 and Mh constraints, demonstrating that they are not in tension with the other constraints.
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.
199676084
Measurement of the differential q**2 spectrum and forward-backward asymmetry for B ---> K* l+ l-
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.
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.
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.
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...
73677709
Vibrational excitation induced by electron beam and cosmic rays in superconductive aluminum bars
We report new measurements of the acoustic excitation of an Al5056 superconductive bar when hit by an electron beam, in a previously unexplored temperature range, down to 0.35 K. These data, analyzed together with previous results obtained for T > 0.54 K, show a vibrational response enhanced by a factor ~ 4.9 with respect to that measured in the normal state. This enhancement explains the anomalous large signals due to cosmic rays previously detected in the NAUTILUS gravitational wave detector.
10433364
A Study of Acollinear Muon Pair Production in $e^+ e^-$ Interactions at $e$({CM}) = 29-{GeV}
We have studied the production of acollinear muon pairs in e/sup +/e/sup -/ interactions using the MAC detector at PEP. The results are totally accounted for by the QED processes e/sup +/e/sup -/..-->..e/sup +/e/sup -/..mu../sup +/..mu../sup -/ and e/sup +/e/sup -/..--> mu../sup +/..mu../sup -/..gamma.. in which only the muon pairs are detected. We have also searched for the production of the supersymmetric partners of the muon. The existence of a spin-0 supersymmetric partner of the muon with a mass <13.8 GeV/c/sup 2/ is excluded at the 95% confidence level.
8791824
Detection of high energy cosmic rays with the resonant gravitational wave detectors NAUTILUS and EXPLORER
Abstract The cryogenic resonant gravitational wave detectors NAUTILUS and EXPLORER, made of an aluminum alloy bar, can detect cosmic ray showers. At temperatures above 1 K, when the material is in the normal-conducting state, the measured signals are in good agreement with the expected values based on the cosmic rays data and on the thermo-acoustic model. When NAUTILUS was operated at the temperature of 0.14 K, in superconductive state, large signals produced by cosmic ray interactions, more energetic than expected, were recorded. The NAUTILUS data in this case are in agreement with the measurements done by a dedicated experiment on a particle beam. The biggest recorded event was in EXPLORER and excited the first longitudinal mode to a vibrational energy of ∼670 K, corresponding to ∼360 TeV absorbed in the bar. Cosmic rays can be an important background in future acoustic detectors of improved sensitivity. At present, they represent a useful tool to verify the gravitational wave antenna performance.
121071887
First results from the MACRO detector at the Gran Sasso Laboratory