D. Green

We report on the test beam results and calibration methods using high energy electrons, pions and muons with the CMS forward calorimeter (HF). The HF calorimeter covers a large pseudorapidity region ( $3\leq|\eta|\leq5$ ), and is essential for a large number of physics channels with missing transverse energy. It is also expected to play a prominent role in the measurement of forward tagging jets in weak boson fusion channels in Higgs production. The HF calorimeter is based on steel absorber with embedded fused-silica-core optical fibers where Cherenkov radiation forms the basis of signal generation. Thus, the detector is essentially sensitive only to the electromagnetic shower core and is highly non-compensating (e/h≈5). This feature is also manifest in narrow and relatively short showers compared to similar calorimeters based on ionization. The choice of fused-silica optical fibers as active material is dictated by its exceptional radiation hardness. The electromagnetic energy resolution is dominated by photoelectron statistics and can be expressed in the customary form as $\frac{a}{\sqrt{E}}\oplus{b}$ . The stochastic term a is 198% and the constant term b is 9%. The hadronic energy resolution is largely determined by the fluctuations in the neutral pion production in showers, and when it is expressed as in the electromagnetic case, a = 280% and b = 11%.

This work summarizes the studies for the Higgs boson searches in CMS at the LHC collider. The main discovery channels are presented and the potential is given for the discovery of the SM Higgs boson and the Higgs bosons of the MSSM. The phenomenology, detector, trigger and reconstruction issues are briefly discussed.

Extensive measurements have been made with pions, electrons and muons on four production wedges of the compact muon solenoid (CMS) hadron barrel (HB) calorimeter in the H2 beam line at CERN with particle momenta varying from 20 to 300 GeV/c. The time structure of the events was measured with the full chain of preproduction front-end electronics running at 34 MHz. Moving-wire radioactive source data were also collected for all scintillator layers in the HB. The energy dependent time slewing effect was measured and tuned for optimal performance.

The Outer Hadron Calorimeter (HCAL HO) of the CMS detector is designed to measure the energy that is not contained by the barrel (HCAL HB) and electromagnetic (ECAL EB) calorimeters. Due to space limitation the barrel calorimeters do not contain completely the hadronic shower and an outer calorimeter (HO) was designed, constructed and inserted in the muon system of CMS to measure the energy leakage. Testing and calibration of the HO was carried out in a 300 GeV/c test beam that improved the linearity and resolution. HO will provide a net improvement in missing E T measurements at LHC energies. Information from HO will also be used for the muon trigger in CMS.

Abstract A proportional drift tube (PDT) of length l = 6 m containing only two potentials for a 5 cm drift distance has been constructed. The coordinate along the drift direction is obtained conventionally. The second coordinate is obtained with an accuracy of ±0.8 mm (rms) by utilizing a combination of time division [1] and vernier pads [2], of length L = 20 cm. The left/right drift time ambiguity can be resolved using separate top and bottom vernier pad readout.

The performance of the Compact Muon Solenoid detector for measuring missing transverse energy is evaluated using fully simulated pp collisions at a center-of-mass energy of 14 TeV at the Large Hadron Collider. For minimum bias events without pileup, a resolution of 6.1 GeV is computed, corresponding to a stochastic contribution of $0.63\sqrt{\Sigma{}E_{\text{T}}} \mathrm{GeV^{1/2}}$ , where ΣET is the summed transverse energy in all calorimeter towers. When the contribution of pileup is included, the resolution degrades according to the overall deposited ΣET with the same stochastic coefficient. For QCD dijet events with event pileup corresponding to a luminosity $\mathcal{L}=2\times10^{33}\mathrm{cm^{-2}s^{-1}}$ , we compute $\sigma=[({3.8} \mathrm{GeV})^2+({0.97} \mathrm{GeV^{1/2}}\sqrt{\Sigma{}E_{\text{T}}})^2+(0.012\Sigma{}E_{\text{T}})^2]^{1/2}$ resulting in a resolution of 45 GeV for jet events with reconstructed transverse momentum of 800 GeV/c. Monte Carlo samples of tt̄ and W+jet events with high-momentum (pT>20 GeV/c) lepton decays leading to true missing transverse energy were used to determine the azimuthal angle resolution to be 0.1 radians (0.2 radians) for a reconstructed missing transverse energy of 200 GeV (100 GeV).

The design and main parameters of the completly redesigned DØ Forward Angle MUon System (FAMUS: 1.0<|η|<2.0) for the next high luminosity Tevatron Collider run are reported. Results of the studies of trigger scintillation counters based on fast scintillator Bicron 404A and WLS bars SOFZ-105 are presented. We report about results of test beam studies of prototype counters including minimum ionizing particles detection efficiency, time resolution and amplitude response. Radiation ageing of scintillating materials for the doses up to 1 Mrad, phototubes magnetic shielding in the fields of up to 700 G and ageing of phototubes are presented. Mini-Drift Tubes (MDTs) are chosen as FAMUS tracking detectors. The detector is a drift wire chamber with a metallic cathode. The detector operates in proportional mode with a fast freon–methane gas mixture to provide high drift velocity, adequate counting rate and low ageing. A description of the performance of the MDT is given. Studies of two prototypes in test beams were performed at FNAL and JINR. Obtained coordinate accuracy is around 0.5 mm r.m.s. All tests show robustness of MDT as tracking detector of the new muon system for a long period in high DØ background radiation conditions.

The trigger electronics for the muon system of the Fermilab D0 detector is described. The hardware trigger consists of VME-based cards designed to find probable tracks in individual chambers and then match these track segments. The fast trigger is highly parallel and able to discern probable tracks from about 15000 trigger cells in under 200 ns from receipt of all bits in the counting house. There is a parallel confirmation trigger with a response time of 1-5 mu s that provides a crude calculation of the momentum and charge of the muon.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

We present the potential for discovering the standard model Higgs boson produced via the vector-boson fusion mechanism. We considered the decay of Higgs bosons to the W+W- final state, with both W-bosons subsequently decaying leptonically. The main background is tt̄ produced in association with one or more jets. This study is based on a full simulation of the CMS detector. The result is that a signal of 5σ significance can be obtained with an integrated luminosity of 12–72 fb-1 for Higgs boson masses in the range 130<mH< 200 GeV. In addition, the major background can be measured directly to 7% from the data with an integrated luminosity of 30 fb-1. We also suggest a method to determine the Higgs mass using template transverse mass distributions.

The requirements of large dynamic range, 40 MHz readout and 4 T magnetic field of the CMS Hadronic calorimeter have led to the development of a custom Hybrid PhotoDiode (HPD). In the last 5 years many improvements have been made in cooperation with DEP1 and Canberra2 to the basic HPD concept to improve the performance. A 200-μm thick 19-channel PIN diode array with various surface treatments has been developed to ensure fast pulse behavior and low optical and capacitive crosstalk.

The energy resolution, linearity and e/π response of model SDC calorimeter configurations were measured. They consisted of a fine sampling lead electromagnetic (e.m.) compartment and either a lead or iron hadronic (HAD) compartment. The data indicate that the lead-scintillator and iron-scintillator hadronic calorimeters have comparable resolutions and linearity after a relative weighting of signals from the EM and HAD compartments is made.

The planned luminosity for the TEVATRON upgrade is ten times higher than at present (/spl Lscr//spl sim/10/sup 32/ cm/sup -2/ s/sup -1/) and involves a time between collisions as small as 132 ns. To operate the D0 muon system in this environment, completely new electronics is required for its 17500 proportional drift tubes. These electronics include a deadtimeless readout, a digital TDC with about 1 ns binning for the wire signals, fast charge integrators and pipelined ADCs for digitizing the pad electrode signals, a new wire signal triggering scheme and its associated trigger logic, and high level DSP processing. Some test results of measurements performed on prototype channels and a comparison with the existing electronics are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

International Journal of Modern Physics AVol. 25, No. 07, pp. 1279-1313 (2010) ReviewsNo AccessHOW PHYSICS DEFINES THE LHC ENVIRONMENT AND DETECTORSD. GREEND. GREENCMS Department, Fermilab, Batavia, IL 60510, USAhttps://doi.org/10.1142/S0217751X10049104Cited by:1 Next AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail This article also appears in At the Leading Edge: The ATLAS and CMS LHC Experiments, ed. D. Green (World Scientific, 2010). References http://en.wikipedia.org/wiki/ATLAS experiment and links therein; http://en.wikipedia.org/wiki/Compact Muon Solenoid. . Google Scholar http://lhc.web.cern.ch/lhc . Google Scholar http://ab-div.web.cern.ch/ab-div/Publications/LHC-DesignReport.html . Google Scholar http://public.web.cern.ch/PUBLIC/en/LHC/CMS-en.html . Google Scholar http://atlas.web.cern.ch/Atlas/index.html . Google ScholarThe CERNJ. Instrum. 3, SO8001 (2008). Google ScholarD. Froidevaux and P. Sphicas, Annu. Rev. Nucl. Part. Sci. 56, 375 (2006), DOI: 10.1146/annurev.nucl.54.070103.181209. Crossref, ISI, ADS, Google ScholarC. Amsleret al., Phys. Lett. B 667, 1 (2008). Crossref, ISI, ADS, Google Scholar and links and references therein , http://en.wikipedia.org/wiki/Dark_matter . Google Scholar J. Gunion et al. , The Higgs Hunter's Guide ( Westview , 2000 ) . Google Scholar and links and references therein , http://en.wikipedia.org/wiki/CompHEP . Google ScholarG. Sterman and S. Weinberg, Phys. Rev. Lett. 39, 1436 (1977), DOI: 10.1103/PhysRevLett.39.1436. Crossref, ISI, ADS, Google Scholar CDF Collab. A. Lister , Hadron Collider Physics 2005 ( Springer , 2006 ) . Google Scholar http://www.linearcollider.org/cms/?pid=1000000 — home page for the ILC . Google Scholar http://physics.uoregon.edu/~lc/wwstudy/concepts/ — links to four design concepts . Google ScholarN. Akchurinet al., Nucl. Instr. Meths. A 537, 537 (2005), DOI: 10.1016/j.nima.2004.07.285. Crossref, ISI, ADS, Google Scholar You currently do not have access to the full text article. Recommend the journal to your library today! FiguresReferencesRelatedDetailsCited By 1A Large Hadron Electron Collider at CERN Report on the Physics and Design Concepts for Machine and DetectorJ L Abelleira Fernandez, C Adolphsen, A N Akay, H Aksakal and J L Albacete et al.4 July 2012 | Journal of Physics G: Nuclear and Particle Physics, Vol. 39, No. 7 Recommended Vol. 25, No. 07 Metrics History PDF download

Hadron shower punchthrough and muon momentum measurements were conducted at 25, 50, 100 and 150 GeV/c, using tracking before, between and after a 7.3 interaction length (λ0) lead block and 7.3λ0 of magnetized iron. The multiplicity and spatial distributions of both hadrons and muons were obtained. Muons were used to study the multiple scattering, the effect of δ rays and associated phenomena, and the momentum resolution. Hadrons were used to study the muon/hadron rejection factor. The measured punchthrough probabilities after 7.3λ0 and 14.6λ0 were consistent with other data. Cuts are described which define the final rejection factor against hadrons.

The radiation hardness properties of a tile/fiber calorimeter with different materials or with different optical path layouts have been studied. Ten calorimeter modules of a geometry similar to that of the proposed SDC calorimeter were irradiated using the BEPC electron beam (1.1 or 1.3 GeV). Radiation damage was quantified by measuring the light yield at various locations within the calorimeter modules at different integrated doses. The recovery process and the dependence on the ambient atmosphere were also studied and correction techniques for various dose and depth profiles were developed.

<b><i>Background:</i></b> Epidemiological studies for identifying patients with Parkinson's disease (PD) or Parkinsonism (PKM) have been limited by their nonrandom sampling techniques and mainly veteran populations. This reduces their use for health services planning. The purpose of this study was to validate algorithms for the case ascertainment of PKM from administrative databases using primary care patients as the reference standard. <b><i>Methods:</i></b> We conducted a retrospective chart abstraction using a random sample of 73,003 adults aged ≥20 years from a primary care Electronic Medical Record Administrative data Linked Database (EMRALD) in Ontario, Canada. Physician diagnosis in the EMR was used as the reference standard and population-based administrative databases were used to identify patients with PKM from the derivation of algorithms. We calculated algorithm performance using sensitivity, specificity, and predictive values and then determined the population-level prevalence and incidence trends with the most accurate algorithms. <b><i>Results:</i></b> We selected, ‘2 physician billing codes in 1 year' as the optimal administrative data algorithm in adults and seniors (≥65 years) due to its sensitivity (70.6-72.3%), specificity (99.9-99.8%), positive predictive value (79.5-82.8%), negative predictive value (99.9-99.7%), and prevalence (0.28-1.20%), respectively. <b><i>Conclusions:</i></b> Algorithms using administrative databases can reliably identify patients with PKM with a high degree of accuracy.

The measurements of radiation damage of tile/fiber scintillator modules to be used for the Solenoid Detector Collaboration (SDC) calorimeter are described. Four tile/fiber scintillator modules were irradiated up to 6 Mrad with the BEPC 1.1 GeV electron beam, and two modules up to 1 Mrad with a 1.3 GeV beam. We have studied the light output at different depths in the modules and at different integrated doses, the recovery process and the dependence on the ambient atmosphere.

The planned luminosity for the upgrade is ten times higher than at present (/spl Lscr//spl sim/10/sup 32/ cm/sup -2/ s/sup -1/) and involves a time between collisions as small as 132 ns. To operate in this environment, completely new electronics is required for the 17500 proportional drift tubes of the system. These electronics include a deadtimeless readout, a digital TDC with about 1 ns binning for the wire signals, fast charge integrators and pipelined ADCs for digitizing the pad electrode signals, a new wire signal triggering scheme and its associated trigger logic, and high level DSP processing. Some test results of measurements performed on prototype channels and a comparison with the existing electronics are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The hybrid photodiode (HPD) will be used for the CMS HCAL readout. A fiber-optic front window is used to reduce optical cross-talk between the pixels of the multi-pixel HPD's. A mismatch of numerical aperture between optical fibers carrying light to the HPD window and the fibers composing the fiber-optic front window of the HPD could lead to light loss. The light loss would appear as a reduced effective quantum efficiency of the device. The goal of this set of measurements was to see if there was in fact a reduction in the effective quantum efficiency of the HPD's.

High energy physics, as exemplified by the SSC, requires the analysis of increasingly complex events which occur at ever higher event rates. The SSC detectors embody an order of magnitude increase in cost and complexity. Research and development for a 500 M$ detector with 500K data channels must procede in step with accelerator design. Up to a decade of R&D at 1% per year (5M$) invested should be expected. This implies the close involvement of industry.