Welathantri Gd Dharmaratna

The DØ detector is a large general purpose detector for the study of short-distance phenomena in high energy antiproton-proton collisions, now in operation at the Fermilab Tevatron collider. The detector focusses upon the detection of electrons, muons, jets and missing transverse momentum. We describe the design and performance of the major elements of the detector, including the tracking chambers, transition radiation detector, liquid argon calorimetry and muon detection. The associated electronics, triggering systems and data acquisition systems are presented. The global mechanical, high voltage, and experiment monitoring and control systems which support the detector are described. We also discuss the design and implementation of software and software support systems that are specific to DØ.

We present new results on the search for the top quark in p¯p collisions at √s=1.8 TeV with an integrated luminosity of 13.5±1.6 pb–1. We have considered t¯t production in the standard model using electron and muon dilepton decay channels ( t¯t→eμ+ jets, ee+ jets, and μμ+ jets) and single-lepton decay channels ( t¯t→e+ jets and μ+ jets) with and without tagging of b quark jets. From all channels we have nine events with an expected background of 3.8±0.9. If we assume that the excess is due to t¯t production, and assume a top mass of 180 GeV/ c2, we obtain a cross section of 8.2±5.1 pb.Received 7 November 1994DOI:https://doi.org/10.1103/PhysRevLett.74.2422©1995 American Physical Society

We present a search for events consistent with the production and decay of the squarks and gluinos of the minimal supersymmetric standard model (MSSM) in the D0 detector at the Fermilab Tevatron $p\overline{p}$ collider. We examined data for events containing large missing transverse energy and three or more jets. We observed no excess of events above the expected yield from standard model processes. For a choice of MSSM parameter values, we set a lower limit at the 95% confidence level on the mass of the gluino of 144 GeV ${/c}^{2}$ for all squark masses and a lower limit of 212 GeV ${/c}^{2}$ for equal squark and gluino masses.

We report a measurement of the inclusive muon and b-quark production cross sections in pp¯ collisions at s=1.8 TeV using the D0 detector at the Fermilab Tevatron collider. The inclusive muon spectrum extends over the kinematic range |yμ|<0.8 and 3.5<pTμ<60GeV/c, and is well described by the expected contributions from various known sources. The b-quark production cross section for |yb|<1.0 and pTb>6GeV/c is extracted, and agrees with next-to-leading order QCD predictions within the experimental and theoretical uncertainties.Received 12 December 1994DOI:https://doi.org/10.1103/PhysRevLett.74.3548©1995 American Physical Society

We present results on the search for the top quark in pp\ifmmode\bar\else\textasciimacron\fi{} collisions at \ensuremath{\surd}s =1.8 TeV with an integrated luminosity of 13.5\ifmmode\pm\else\textpm\fi{}1.6 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$. We have considered tt\ifmmode\bar\else\textasciimacron\fi{} production in the standard model using electron and muon dilepton decay channels (tt\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}e\ensuremath{\mu}+jets, ee+jets, and \ensuremath{\mu}\ensuremath{\mu}+jets) and single-lepton decay channels (tt\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}e+jets and \ensuremath{\mu}+jets) with and without tagging of b quark jets. An analysis of these data optimized for top quark masses below 140 GeV/${\mathit{c}}^{2}$ gives a lower top quark mass limit of 128 GeV/${\mathit{c}}^{2}$. An analysis optimized for higher top quark masses yields 9 events with an expected background of 3.8\ifmmode\pm\else\textpm\fi{}0.9. If we assume that the excess is due to tt\ifmmode\bar\else\textasciimacron\fi{} production, and assuming a top quark mass of 180 GeV/${\mathit{c}}^{2}$, we obtain a cross section of 8.2\ifmmode\pm\else\textpm\fi{}5.1 pb.

The inclusive cross sections times leptonic branching ratios for W and Z boson production in PbarP collisions at Sqrt(s)=1.8 TeV were measured using the D0 detector at the Fermilab Tevatron collider: Sigma_W*B(W->e, nu) = 2.36 +/- 0.07 +/- 0.13 nb, Sigma_W*B(W->mu,nu) = 2.09 +/- 0.23 +/- 0.11 nb, Sigma_Z*B(Z-> e, e) = 0.218 +/- 0.011 +/- 0.012 nb, Sigma_Z*B(Z->mu,mu) = 0.178 +/- 0.030 +/- 0.009 nb. The first error is the combined statistical and systematic uncertainty, and the second reflects the uncertainty in the luminosity. For the combined electron and muon analyses we find: [Sigma_W*B(W->l,nu)]/[Sigma_Z*B(Z->l,l)] = 10.90 +/- 0.49. Assuming Standard Model couplings, this result is used to determine the width of the W boson: Gamma(W) = 2.044 +/- 0.093 GeV.

It is well known that the single-polarization asymmetries vanish in QCD with massless quarks. But, heavy quarks with a nonzero mass should be transversely polarized due to the breakdown of the helicity conservation. In this paper we give the exact fourth-order perturbative QCD predictions for the transverse polarization from all QCD subprocesses, q+q\ensuremath{'}\ensuremath{\rightarrow}q+q\ensuremath{'}, q+g\ensuremath{\rightarrow}q+g, g+g\ensuremath{\rightarrow}q+q\ifmmode\bar\else\textasciimacron\fi{}, and q+q\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}q\ensuremath{'}+q\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{'}, which are significant for heavy quark production, with a description of the method of calculation. The kinematical dependence of the polarization is discussed. Top quark polarization from gluon fusion and quark annihilation processes, which are the important subprocesses at high energies, is estimated and its significance is discussed. \textcopyright{} 1996 The American Physical Society.

First experimental results are presented from a search for events with a rapidity gap between jets. The D0 detector was used to examine events produced by the Fermilab Tevatron pp\ifmmode\bar\else\textasciimacron\fi{} collider at \ensuremath{\surd}s =1.8 TeV. The fraction of events with an observed rapidity gap between the two highest transverse energy (${\mathit{E}}_{\mathit{T}}$) jets is measured as a function of the pseudorapidity separation between the jet edges (\ensuremath{\Delta}${\mathrm{\ensuremath{\eta}}}_{\mathit{c}}$). An upper limit at the 95% confidence level of 1.1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}2}$ is obtained on the fraction of events with non particles between the jets, for events with \ensuremath{\Delta}${\mathrm{\ensuremath{\eta}}}_{\mathit{c}}$&gt;3 and jet ${\mathit{E}}_{\mathit{T}}$ greater than 30 GeV.

The series of upgrades to the Large Hadron Collider, culminating in the High Luminosity Large Hadron Collider, will enable a significant expansion of the physics program of the CMS experiment. However, the accelerator upgrades will also make the experimental conditions more challenging, with implications for detector operations, triggering, and data analysis. The luminosity of the proton-proton collisions is expected to exceed $2-3\times10^{34}$~cm$^{-2}$s$^{-1}$ for Run 3 (starting in 2022), and it will be at least $5\times10^{34}$~cm$^{-2}$s$^{-1}$ when the High Luminosity Large Hadron Collider is completed for Run 4. These conditions will affect muon triggering, identification, and measurement, which are critical capabilities of the experiment. To address these challenges, additional muon detectors are being installed in the CMS endcaps, based on Gas Electron Multiplier technology. For this purpose, 161 large triple-Gas Electron Multiplier detectors have been constructed and tested. Installation of these devices began in 2019 with the GE1/1 station and will be followed by two additional stations, GE2/1 and ME0, to be installed in 2023 and 2026, respectively. The assembly and quality control of the GE1/1 detectors were distributed across several production sites around the world. We motivate and discuss the quality control procedures that were developed to standardize the performance of the detectors, and we present the final results of the production. Out of 161 detectors produced, 156 detectors passed all tests, and 144 detectors are now installed in the CMS experiment. The various visual inspections, gas tightness tests, intrinsic noise rate characterizations, and effective gas gain and response uniformity tests allowed the project to achieve this high success rate.

The distribution of the transverse energy in jets has been measured in pp collisions at s=1.8 TeV TeV using the DØ detector at Fermilab. This measurement of the jet shape is made as a function of jet transverse energy in both the central and forward rapidity regions. Jets are shown to narrow both with increasing transverse energy and with increasing rapidity. Next-to-leading order partonic QCD calculations are compared to the data. Although the calculations qualitatively describe the data, they are shown to be very dependent on renormalization scale, parton clustering algorithm, and jet direction definition and they fail to describe the data in all regions consistently.

It is well known that single-polarization asymmetries are large in hyperon production in contrast with naive QCD predictions. We have explored the possibility of polarization of quarks through "gluon fusion," assuming that the quark mass can be significant at energies of interest. The fourth-order contribution to the single-spin asymmetry in $g+g\ensuremath{\rightarrow}s+\overline{s}$ is calculated. Properties of the polarization of the strange quark in the hadron center-of-mass frame are discussed. A fit to the hyperon polarization is presented that reproduces the unique and striking kinematic dependence of the data. This is evidence that gluon fusion can be taken as a serious candidate for the "seed" of polarization.

The results of a search for W boson pair production in pp¯ collisions at s=1.8TeV with subsequent decay to dilepton ( eμ,ee, and μμ) channels are presented. One event is observed with an expected background of 0.56±0.13 events with an integrated luminosity of approximately 14pb−1. Assuming equal strengths for the WWZ and WWγ gauge boson coupling parameters κ and λ, limits on the CP-conserving anomalous coupling constants are −2.6<Δκ<2.8 and −2.1<λ<2.1 at the 95% confidence level.Received 10 March 1995DOI:https://doi.org/10.1103/PhysRevLett.75.1023©1995 American Physical Society

The W W γ gauge boson couplings were measured using pp → ℓνγ + X (ℓ = e, µ) events at √ s = 1.8 TeV observed with the DØ detector at the Fermilab Tevatron Collider.The signal, obtained from the data corresponding to an integrated luminosity of 13.8 pb -1 , agrees well with the Standard Model prediction.A fit to the photon transverse energy spectrum yields limits at the 95% confidence level on the CP-conserving anomalous coupling parameters of -1.6 < ∆κ < 1.8 (λ = 0) and -0.6 < λ < 0.6 (∆κ = 0).

We describe the results of beam tests of three uranium-liquid argon calorimeter modules constructed for the DØ detector at the Fermilab Tevatron collider. As part of the calibration procedure, these modules were exposed to beams of electrons, pions and muons between 10 and 150 GeV/c before their installation in the end calorimeter of the completed DØ detector. We obtain an electromagnetic sampling resolution of 15.7%/√E and constant term of 0.3%. The hadronic sampling resolution is 45%/√E (degraded to 50%/√E by the effects of upstream material) and the constant term is 4%. The calorimeter is linear to 0.5%, and the electromagnetic to hadronic response ratio is between 1.02 and 1.09 over this range of momenta. For an electron efficiency of 95% we obtain a rejection factor against pions of ∼ 900-3000 for particles in the momentum range between 50 and 150 GeV/c. We also compare our results with the predictions of a detailed Monte Carlo simulation.

We performed a direct search for the anomalous ZZγ and Zγγ couplings by studying p¯p→ℓℓγ+X (ℓ=e,μ) events at √s=1.8 TeV with the D0 detector at the Fermilab Tevatron Collider. A fit to the transverse energy spectrum of the photon in the signal events, based on the data set corresponding to an integrated luminosity of 14.3pb−1 ( 13.7pb−1) for the electron (muon) channel, yields the following 95% confidence level limits on the anomalous CP-conserving ZZγ couplings: |hZ30|<1.8 ( hZ40=0) and |hZ40|<0.5 ( hZ30=0), for a form-factor scale Λ=500 GeV. Limits for the Zγγ couplings and CP-violating couplings are also discussed.Received 10 March 1995DOI:https://doi.org/10.1103/PhysRevLett.75.1028©1995 American Physical Society

The ratio of the number of $W+1$ jet to $W+0$ jet events is measured with the D0 detector using data from the 1992--93 Tevatron Collider run. For the $W\ensuremath{\rightarrow}e\ensuremath{\nu}$ channel with a minimum jet ${E}_{T}$ cutoff of 25 GeV, the experimental ratio is $0.065\ifmmode\pm\else\textpm\fi{}0.003\left(\mathrm{stat}\right)\ifmmode\pm\else\textpm\fi{}0.007\left(\mathrm{syst}\right)$. Next-to-leading order QCD predictions for various parton distributions agree well with each other and are all over 1 standard deviation below the measurement. Varying the strong coupling constant ${\ensuremath{\alpha}}_{s}$ in both the parton distributions and the partonic cross sections simultaneously does not remove this discrepancy.

The high-luminosity phase of the Large Hadron Collider (HL-LHC) will result in ten times higher particle background than measured during the first phase of LHC operation. In order to fully exploit the highly-demanding operating conditions during HL-LHC, the Compact Muon Solenoid (CMS) Collaboration will use Gas Electron Multiplier (GEM) detector technology. The technology will be integrated into the innermost region of the forward muon spectrometer of CMS as an additional muon station called GE1∕1. The primary purpose of this auxiliary station is to help in muon reconstruction and to control level-1 muon trigger rates in the pseudo-rapidity region 1.6≤|η|≤2.2. The new station will contain trapezoidal-shaped GEM detectors called GE1∕1 chambers. The design of these chambers is finalized, and the installation is in progress during the Long Shutdown phase two (LS-2) that started in 2019. Several full-size prototypes were built and operated successfully in various test beams at CERN. We describe performance measurements such as gain, efficiency, and time resolution of these prototype chambers, developed after years of R&D, and summarize their behavior in different gas compositions as a function of the applied voltage.

The global topologies of inclusive three- and four-jet events produced in $\overline{p}p$ interactions are described. The three- and four-jet events are selected from data recorded by the D0 detector at the Fermilab Tevatron Collider operating at a center-of-mass energy of $\sqrt{s}=1800$ GeV. The measured, normalized distributions of various topological variables are compared with parton-level predictions of tree-level QCD calculations. The parton-level QCD calculations are found to be in good agreement with the data. The studies also show that the topological distributions of the different subprocesses involving different numbers of quarks are very similar and reproduce the measured distributions well. The parton-shower Monte Carlo generators provide a less satisfactory description of the topologies of the three- and four-jet events.

We present a measurement of the top quark pair (tt¯) production cross section (σtt¯) in pp¯ collisions at a center-of-mass energy of 1.96 TeV using 230 pb−1 of data collected by the DØ detector at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), large missing transverse energy, and at least four jets, and extract the tt¯ content of the sample based on the kinematic characteristics of the events. For a top quark mass of 175 GeV, we measure σtt¯=6.7−1.3+1.4(stat)−1.1+1.6(syst)±0.4(lumi)pb, in good agreement with the standard model prediction.

We report on a search for second generation scalar leptoquarks with the DO detector at the Fermilab Tevatron $p\overline{p}$ collider at $\sqrt{s}=1.8$ TeV. This search is based on 12.7 ${\mathrm{pb}}^{\ensuremath{-}1}$ of data. Second generation leptoquarks are assumed to be produced in pairs and to decay into a muon and quark with branching ratio $\ensuremath{\beta}$ or into a neutrino and quark with branching ratio $1\ensuremath{-}\ensuremath{\beta}$. We obtain cross section times branching ratio limits as a function of leptoquark mass and set lower limits on the leptoquark mass at the 95% confidence level.

Cadmium Sulfide (CdS) thin films were electrodeposited successfully on to Indium Tin Oxide (ITO) coated glass substrates from an aqueous solution of pH 1.4 containing 0.3M CdCl2 and 0.03M Na2S2O3 or Thiourea with the aim of using in CdS/CdTe solar cells. Properties of CdS thin films prepared at different deposition voltages, deposition time periods, deposition temperatures and annealing temperatures were investigated using the current-voltage (I-V) plots. It was found that good quality CdS layers were formed under the deposition conditions of -1.13V for a period of 45 minutes in a solution of temperature at 46 oC. The performance of the CdS layers was improved significantly after annealing the samples at 400 oC for a period of 20 min. The properties of CdS thin films prepared by two and three electrode configurations and using two different electrolytes were compared using the current-voltage plots. It was found that there is a significant improvement of photocurrent of the samples prepared with two electrodes in Thiourea as the S source in comparison with the samples prepared with Na2S2O3. The analysis of XRD spectra showed the hexagonal crystal structure of CdS films confirming the quality of the films prepared by this method. In addition, absorption spectra showed band gap value of 2.42 eV proving that the samples were of good quality. Atomic Force Microscopy (AFM) analysis showed that the roughness values of CdS samples were in the range of 10-15 nm. Film thicknesses of the samples were in the range of 175-225 nm according to the optical profilometric data. Keywords. Cadmium sulfide, electrodeposition, electrolyte, two-electrode, photocurrent.

Gas Electron Multiplier (GEM) technology, in particular triple-GEM, was selected for the upgrade of the CMS endcap muon system following several years of intense effort on R&D. The triple-GEM chambers (GE1/1) are being installed at station 1 during the second long shutdown with the goal of reducing the Level-1 muon trigger rate and improving the tracking performance in the harsh radiation environment foreseen in the future LHC operation [1]. A first installation of a demonstrator system started at the beginning of 2017: 10 triple-GEM detectors were installed in the CMS muon system with the aim of gaining operational experience and demonstrating the integration of the GE1/1 system into the trigger. In this context, a dedicated Detector Control System (DCS) has been developed, to control and monitor the detectors installed and integrating them into the CMS operation. This paper presents the slice test DCS, describing in detail the different parts of the system and their implementation.

The CMS muon system in the region with 2.03<|η|<2.82 is characterized by a very harsh radiation environment which can generate hit rates up to 144 kHz/cm2 and an integrated charge of 8 C/cm2 over ten years of operation. In order to increase the detector performance and acceptance for physics events including muons, a new muon station (ME0) has been proposed for installation in that region. The technology proposed is Triple—Gas Electron Multiplier (Triple-GEM), which has already been qualified for the operation in the CMS muon system. However, an additional set of studies focused on the discharge probability is necessary for the ME0 station, because of the large radiation environment mentioned above. A test was carried out in 2017 at the Cern High energy AcceleRator Mixed (CHARM) facility, with the aim of giving an estimation of the discharge probability of Triple-GEM detectors in a very intense radiation field environment, similar to the one of the CMS muon system. A dedicated standalone Geant4 simulation was performed simultaneously, to evaluate the behavior expected in the detector exposed to the CHARM field. The geometry of the detector has been carefully reproduced, as well as the background field present in the facility. This paper presents the results obtained from the Geant4 simulation, in terms of sensitivity of the detector to the CHARM environment, together with the analysis of the energy deposited in the gaps and of the processes developed inside the detector. The discharge probability test performed at CHARM will be presented, with a complete discussion of the results obtained, which turn out to be consistent with measurements performed by other groups.

A search for a heavy charged gauge boson, W′, using the decay channels W′ → eν and W′ → τν → eννν is reported. The data used in the analysis were collected by the DØ experiment at the Fermilab Tevatron during the 1992-93 pp collider run from an integrated luminosity of 13.9 ± 0.8 pb−1 at s=1.8 TeV. Assuming that the neutrino from W′ decay is stable and has a mass significantly less than mW′, an upper limit at the 95% confidence level is set on the cross section times branching ratio for pp → W′ → eν. A W′ with the same couplings to quarks and leptons as the standard model W boson is excluded for mW′ < 610 GeV/c2.

The upgrade of the CMS detector for the high luminosity LHC (HL-LHC) will include gas electron multiplier (GEM) detectors in the end-cap muon spectrometer. Due to the limited supply of large area GEM detectors, the Korean CMS (KCMS) collaboration had formed a consortium with Mecaro Co., Ltd. to serve as a supplier of GEM foils with area of approximately 0.6 m2. The consortium has developed a double-mask etching technique for production of these large-sized GEM foils. This article describes the production, quality control, and quality assessment (QA/QC) procedures and the mass production status for the GEM foils. Validation procedures indicate that the structure of the Korean foils are in the designed range. Detectors employing the Korean foils satisfy the requirements of the HL-LHC in terms of the effective gain, response uniformity, rate capability, discharge probability, and hardness against discharges. No aging phenomena were observed with a charge collection of 82 mC cm−2. Mass production of KCMS GEM foils is currently in progress.

Abstract The Gas Electron Multiplier (GEM) detectors of the GE1/1 station of the CMS experiment have been operated in the CMS magnetic field for the first time on the 7 th of October 2021. During the magnetic field ramps, several discharge phenomena were observed, leading to instability in the GEM High Voltage (HV) power system. In order to reproduce the behavior, it was decided to conduct a dedicated test at the CERN North Area with the Goliath magnet, using four GE1/1 spare chambers. The test consisted in studying the characteristics of discharge events that occurred in different detector configurations and external conditions. Multiple magnetic field ramps were performed in sequence: patterns in the evolution of the discharge rates were observed with these data. The goal of this test is the understanding of the experimental conditions inducing discharges and short circuits in a GEM foil. The results of this test lead to the development of procedure for the optimal operation and performance of GEM detectors in the CMS experiment during the magnet ramps. Another important result is the estimation of the probability of short circuit generation, at 68 % confidence level, p short HV OFF = 0.42 -0.35 +0.94 % with detector HV OFF and p short HV OFF &lt; 0.49% with the HV ON. These numbers are specific for the detectors used during this test, but they provide a first quantitative indication on the phenomenon, and a point of comparison for future studies adopting the same procedure.

Long-chain normal aliphatic alcohols are found to suppress photocorrosion and increase the efficiency of a cuprous oxide photoelectrochemical cell with aqueous thiocyanate solution as the electrolyte. It is suggested that alcohols inhibit corrosion by surface adsorption.

Abstract A temperature monitoring system based on fibre Bragg grating (FBG) fibre optic sensors has been developed for the gas electron multiplier (GEM) chambers of the Compact Muon Solenoid (CMS) detector. The monitoring system was tested in prototype chambers undergoing a general test of the various technological solutions adopted for their construction. The test lasted about two years and was conducted with the chambers being installed in the CMS detector and operated during regular experimental running. In this paper, we present test results that address the choice of materials and procedures for the production and installation of the FBG temperature monitoring system in the final GEM chambers.

We present analytical calculations, Finite Element Analysis modelling, and physical measurements of the interstrip capacitances for different potential strip geometries and dimensions of the readout boards for the GE2/1 triple-Gas Electron Multiplier detector in the CMS muon system upgrade. The main goal of the study is to find configurations that minimize the interstrip capacitances and consequently maximize the signal-to-noise ratio for the detector. We find agreement at the 1.5–4.8% level between the two methods of calculations and on the average at the 17% level between calculations and measurements. A configuration with halved strip lengths and doubled strip widths results in a measured 27–29% reduction over the original configuration while leaving the total number of strips unchanged. We have now adopted this design modification for all eight module types of the GE2/1 detector and will produce the final detector with this new strip design.

In the reaction p+p→Λ+X with up to all three known particles polarized (which will be studied in Fermilab’s upcoming polarization facility) the relationship of the various polarization observables to the 20 three-in-three-out amplitudes is simply given by two 4-by-4 and 12 2-by-2 submatrices. The QCD predictions are said to be the firmest in the large momentum transfer region. There, in the lowest order perturbative calculations only two amplitudes are nonzero, thus yielding only six nonzero polarization quantities with four relations among them. For smaller momentum transfers, Regge model predictions for double correlation observables may be tested even though such models have failed to predict the large single Λ polarization which has been the subject of so much speculation in recent years. The three models which attempt to explain this large polarization can also be tested in these reactions with up to three polarized particles since they should yield small asymmetries for the incident particles. All in all, such polarization experiments will significantly strengthen the testing of the various proposed theoretical models.

A study of the conductivity characteristics of ferric tungstate indicates that this material undergoes a semiconductor-to-metal transition at ca. 182 °C.

A simple automated device have been designed and constructed in order to release a predetermined amount of liquid from a container. This preliminary study indicates that the device releases water with an accuracy of ± 0.2 ml and 92% of the time the accuracy is within ± 0.1 ml. The volume of the water released could be adjusted to any predetermined value. It could fill a 500 ml water bottle in about 25 s. The device could be used for other liquids with low viscosity. This could be modified and used for many applications ranging from small-scale shops selling any kind of liquid by volume to large-scale industries such as bottling any liquid. The accuracy could be improved further. The main advantage is that the device can be easily manufactured locally at low cost.

A comparison of thunder signatures between cloud and ground flashes associated with audio frequency pressure variations over Sri Lanka

Grass has a high leaf density and requires minimum space to grow. This experiment was designed to determine the sound absorption behaviour of six grass species (Zoysia matrella (L) Merr., Stenotaphrum dimidiatum(L.) Brongn, Panicum repens (L.), Eleusine indica (L.) Gaertn., Axonopus compressus (Sw) P. Beauv, and Ischaemum sp.) for their possible use as noise screens. The sound absorption of each morphological leaf structure was studied. For Sound Absorption Coefficients (SAC) (α) studies, the reverberation room method under ISO 345:2003 standards was followed. A B&amp;K dodecahedron Omni-directional speaker, power amplifier, and 2250L handheld analyser were used for reverberation time and RT60 measurements. Microscopic images of grass leaves were analysed using ImageJ software. This study revealed that grasses with the highest and lowest SAC for higher noise frequencies (&gt; 1500 Hz) are S. dimidiatum Brongn and A. compressus, respectively. The SAC of S. dimidiatum Brongn positively correlated with noise frequency. In general, the correlation of SAC (α) with noise frequency (f) is in the form of log10α = a1log10f + b1 where a1 and b1 are grass type-dependent constants. The morphological parameters like total leaf area, total sample area, plant height, and sample dry weight strongly correlated with the SAC. But leaf thickness, length, width, surface area, and the weight of the sample poorly correlated with SAC in the frequency range.

The electrical conductivity characteristics of ferric metavanadate are studied. It is found that this material undergoes a conductivity transition at 168 degrees C.

This paper has been withdrawn because it has not been vetted by CMS

The Phase-II high luminosity upgrade to the Large Hadron Collider (LHC) is planned for 2023, significantly increasing the collision rate and therefore the background rate, particularly in the high $\eta$ region. To improve both the tracking and triggering of muons, the Compact Muon Solenoid (CMS) Collaboration plans to install triple-layer Gas Electron Multiplier (GEM) detectors in the CMS muon endcaps. Demonstrator GEM detectors were installed in CMS during 2017 to gain operational experience and perform a preliminary investigation of detector performance. We present the results of triple-GEM detector performance studies performed in situ during normal CMS and LHC operations in 2018. The distribution of cluster size and the efficiency to reconstruct high $p_T$ muons in proton--proton collisions are presented as well as the measurement of the environmental background rate to produce hits in the GEM detector.

The Ceylon Journal of Science is published by the University of Peradeniya, Sri Lanka. Full text available. The journal also has its own website. The Ceylon Journal of Science is a continuation of the Ceylon Journal of Science (Biological Sciences) which is no longer being published as a separate journal. The history of the journal can be found here.From May 2020, Ceylon Journal of Science is indexed in DOAJ.

Abstract In 2018, a system of large-size triple-GEM demonstrator chambers was installed in the CMS experiment at CERN's Large Hadron Collider (LHC). The demonstrator's design mimicks that of the final detector, installed for Run-3. A successful Monte Carlo (MC) simulation of the collision-induced background hit rate in this system in proton-proton collisions at 13 TeV is presented. The MC predictions are compared to CMS measurements recorded at an instantaneous luminosity of 1.5 ×10 34 cm -2 s -1 . The simulation framework uses a combination of the FLUKA and GEANT4 packages. FLUKA simulates the radiation environment around the GE1/1 chambers. The particle flux by FLUKA covers energy spectra ranging from 10 -11 to 10 4 MeV for neutrons, 10 -3 to 10 4 MeV for γ's, 10 -2 to 10 4 MeV for e ± , and 10 -1 to 10 4 MeV for charged hadrons. GEANT4 provides an estimate of the detector response (sensitivity) based on an accurate description of the detector geometry, the material composition, and the interaction of particles with the detector layers. The detector hit rate, as obtained from the simulation using FLUKA and GEANT4, is estimated as a function of the perpendicular distance from the beam line and agrees with data within the assigned uncertainties in the range 13.7-14.5%. This simulation framework can be used to obtain a reliable estimate of the background rates expected at the High Luminosity LHC.

physica status solidi (a)Volume 69, Issue 1 p. K129-K130 Short Note Semiconduction in Ammonium Phosphomolybdate K. Tennakone, K. Tennakone Department of Physics, Ruhuna University College, Matara Search for more papers by this authorW. G. D. Dharmaratna, W. G. D. Dharmaratna Department of Physics, Ruhuna University College, Matara Search for more papers by this authorS. C. Jayewardena, S. C. Jayewardena Department of Physics, Ruhuna University College, Matara Search for more papers by this author K. Tennakone, K. Tennakone Department of Physics, Ruhuna University College, Matara Search for more papers by this authorW. G. D. Dharmaratna, W. G. D. Dharmaratna Department of Physics, Ruhuna University College, Matara Search for more papers by this authorS. C. Jayewardena, S. C. Jayewardena Department of Physics, Ruhuna University College, Matara Search for more papers by this author First published: 16 January 1982 https://doi.org/10.1002/pssa.2210690173 Matara, Sri Lanka. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. References 1 A. I. Vogel, Quantitative Inorganic Analysis, 3rd ed., Longmans Green, London 1962 (p. 574). 2 J. Hladik (Ed.), Physics of Electrolytes, Vol. I, Academic Press, New York 1972. 3 G. D. Mahan and W. L. Roth, Superionic Conductors, Plenum Press, New York 1976. Volume69, Issue116 January 1982Pages K129-K130 ReferencesRelatedInformation

The Journal of the National Science Foundation of Sri Lanka publishes the results of research in all aspects of Science and Technology. The journal also has a website at http://www.nsf.gov.lk/. 2020 Impact Factor: 0.515The JNSF provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge.

It is well known that the single polarization asymmetries are large in hyperon production in contrast with naive Quantum Chromodynamics predictions. vVe have explored the possibility of polarization of quarks in QCD subprocesses, assuming that the quark mass can be significant .at energies of interest. The fourth order contribution to the single spin asymmetry in each important subprocess for strange quark production is calculated. Mass dependence and the kinematical properties of the polarization of the strange quark in the partons' center-of-mass frame are discussed. The s-quark polarization in the hadrons' center-of-mass frame is obtained by performing the convolution integrations with the initial state parton distribution functions. A fit to the hyperon polarization is presented that reproduces the unique and striking kinematic dependence of the data. This is evidence that the "seed" of the polarization is in the basic scattering process and it is dominated by the gluon fusion subprocess.

The D0 calorimeter system, cylindrical central calorimeter and two end calorimeters, is constructed with minimal cracks and dead regions in order to provide essentially hermetic coverage over the full solid angle. The effect of the existing few construction features which could perturb the uniformity of the calorimeter is studied in detail with beam tests. The results with the correction algorithms are presented. A comparison with the Monte Carlo simulation is made.

We have explored the possibility of polarization of quarks through ‘‘Gluon Fusion,’’ assuming that the quark mass can be significant at energies of interest. The fourth order contribution to the single spin asymmetry is calculated. A rough fit to the hyperon polarization data is given. It is claimed that the gluon fusion can be taken as a serious candidate for the ‘seed’ of polarization.