Application of large area SiPMs for the readout of a plastic scintillator based timing detector

In this study an array of eight 6 mm x 6 mm area SiPMs was coupled to the end of a long plastic scintillator counter which was exposed to a 2.5 GeV/c muon beam at the CERN PS. Timing characteristics of bars with dimensions 150 cm x 6 cm x 1 cm and 120 cm x 11 cm x 2.5 cm have been studied. An 8-channel SiPM anode readout ASIC (MUSIC R1) based on a novel low input impedance current conveyor has been used to read out and amplify SiPMs independently and sum the signals at the end. Prospects for applications in large-scale particle physics detectors with timing resolution below 100 ps are provided in light of the results

Application of large area SiPMs for the readout of a plastic scintillator based timing detector

In this study an array of eight 6 mm x 6 mm area SiPMs was coupled to the end of a long plastic scintillator counter which was exposed to a 2.5 GeV/c muon beam at the CERN PS. Timing characteristics of bars with dimensions 150 cm x 6 cm x 1 cm and 120 cm x 11 cm x 2.5 cm have been studied. An 8-channel SiPM anode readout ASIC (MUSIC R1) based on a novel low input impedance current conveyor has been used to read out and amplify SiPMs independently and sum the signals at the end. Prospects for applications in large-scale particle physics detectors with timing resolution below 100 ps are provided in light of the results

Higgs boson production via vector-like top-partner decays: diphoton or multilepton plus multijets channels at the LHC

We first build a minimal model of vector-like quarks where the dominant Higgs boson production process at LHC -- the gluon fusion -- can be significantly suppressed, being motivated by the recent stringent constraints from the search for direct Higgs production over a wide Higgs mass range. Within this model, compatible with the present experimental constraints on direct Higgs searches, we demonstrate that the Higgs ($h$) production via a heavy vector-like top-partner ($t_2$) decay, $pp \to t_2 \bar t_2$, $t_2\to t h$, allows to discover a Higgs boson at the LHC and measure its mass, through the decay channels $h\to \gamma\gamma$ or $h\to ZZ$. We also comment on the recent hint in LHC data from a possible $\sim 125$ GeV Higgs scalar, in the presence of heavy vector-like top quarks.Comment: 14 pages, 8 figure

Effects of Residue Background Events in Direct Dark Matter Detection Experiments on the Determination of the WIMP Mass

In the earlier work on the development of a model-independent data analysis method for determining the mass of Weakly Interacting Massive Particles (WIMPs) by using measured recoil energies from direct Dark Matter detection experiments directly, it was assumed that the analyzed data sets are background-free, i.e., all events are WIMP signals. In this article, as a more realistic study, we take into account a fraction of possible residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced events in our data sets. Our simulations show that, for the determination of the WIMP mass, the maximal acceptable fraction of residue background events in the analyzed data sets of O(50) total events is ~20%, for background windows of the entire experimental possible energy ranges, or in low energy ranges; while, for background windows in relatively higher energy ranges, this maximal acceptable fraction of residue background events can not be larger than ~10%. For a WIMP mass of 100 GeV with 20% background events in the windows of the entire experimental possible energy ranges, the reconstructed WIMP mass and the 1-sigma statistical uncertainty are ~97 GeV^{+61%}_{-35%} (~94 GeV^{+55%}_{-33%} for background-free data sets).Comment: 27 pages, 22 eps figures; v2: revised version for publication, references added and update

ATLAS Infrastructure

This document describes the civil engineering and infrastructure work done on the surface and underground for the ATLAS experiment at point 1 of the LHC ring

The EDELWEISS Experiment : Status and Outlook

The EDELWEISS Dark Matter search uses low-temperature Ge detectors with heat and ionisation read- out to identify nuclear recoils induced by elastic collisions with WIMPs from the galactic halo. Results from the operation of 70 g and 320 g Ge detectors in the low-background environment of the Modane Underground Laboratory (LSM) are presented.Comment: International Conference on Dark Matter in Astro and Particle Physics (Dark 2000), Heidelberg, Germany, 10-16 Jul 2000, v3 minor revision

A Randomized Controlled Trial Translating the Diabetes Prevention Program to a University Worksite, Ohio, 2012-2014

INTRODUCTION: Working adults spend much time at the workplace, an ideal setting for wellness programs targeting weight loss and disease prevention. Few randomized trials have evaluated the efficacy of worksite diabetes prevention programs. This study evaluated the efficacy of a worksite lifestyle intervention on metabolic and behavioral risk factors compared with usual care. METHODS: A pretest-posttest control group design with 3-month follow-up was used. Participants with prediabetes were recruited from a university worksite and randomized to receive a 16-week lifestyle intervention (n = 35) or usual care (n = 34). Participants were evaluated at baseline, postintervention, and 3-month follow-up. Dietary intake was measured by a food frequency questionnaire and level of physical activity by accelerometers. Repeated measures analysis of variance compared the change in outcomes between and within groups. RESULTS: Mean (standard error [SE]) weight loss was greater in the intervention (-5.5% [0.6%]) than in the control (-0.4% [0.5%]) group (P < .001) postintervention and was sustained at 3-month follow-up (P < .001). Mean (SE) reductions in fasting glucose were greater in the intervention (-8.6 [1.6] mg/dL) than in the control (-3.7 [1.6] mg/dL) group (P = .02) postintervention; both groups had significant glucose reductions at 3-month follow-up (P < .001). In the intervention group, the intake of total energy and the percentage of energy from all fats, saturated fats, and trans fats decreased, and the intake of dietary fiber increased (all P < .01) postintervention. CONCLUSION: The worksite intervention improved metabolic and behavioral risk factors among employees with prediabetes. The long-term impact on diabetes prevention and program sustainability warrant further investigation

First Results of the EDELWEISS WIMP Search using a 320 g Heat-and-Ionization Ge Detector

The EDELWEISS collaboration has performed a direct search for WIMP dark matter using a 320 g heat-and-ionization cryogenic Ge detector operated in a low-background environment in the Laboratoire Souterrain de Modane. No nuclear recoils are observed in the fiducial volume in the 30-200 keV energy range during an effective exposure of 4.53 kg.days. Limits for the cross-section for the spin-independent interaction of WIMPs and nucleons are set in the framework of the Minimal Supersymmetric Standard Model (MSSM). The central value of the signal reported by the experiment DAMA is excluded at 90% CL.Comment: 14 pages, Latex, 4 figures. Submitted to Phys. Lett.