R. Walker

We report results of an electron-beam-dump search for neutral particles with masses in the range 1 to 15 MeV and lifetimes \ensuremath{\tau} between ${10}^{\mathrm{\ensuremath{-}}14}$ and ${10}^{\mathrm{\ensuremath{-}}10}$ s. No evidence was found for such an object. We fule out the existence of any 1.8-MeV pseudoscalar boson with \ensuremath{\tau}>8.2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}15}$ s and an absorption cross section in matter less than 1 mb per nucleon, and exclude \ensuremath{\tau}>1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}14}$ s were its cross section to equal 50 mb per nucleon. In conjunction with measurements of the electron's anomalous magnetic moment, this experiment shows that the narrow positron peaks observed in heavy-ion collisions at the Gessellschaft fu\ifmmode\ddot\else\textasciidieresis\fi{}r Schwerionenforschung are not due to an elementary pseudoscalar.

We report measurements of the proton form factors GEp and GMp extracted from elastic scattering in the range 1≤Q2≤3 (GeV/c)2 with total uncertainties < 15% in GEp and < 3% in GMp. Comparisons are made to theoretical models, including those based on perturbative QCD, vector-meson dominance, QCD sum rules, and diquark constituents in the proton. The results for GEp are somewhat larger than indicated by most theoretical parametrizations, and the ratios of the Pauli and Dirac form factors Q2(F2pF1p) are lower in value and demonstrate a weaker Q2 dependence than those predictions. A global extraction of the elastic form factors from several experiments in the range 0.1 0.1<Q2<10 (GeV/c)2 is also presented.Received 4 November 1993DOI:https://doi.org/10.1103/PhysRevD.49.5671©1994 American Physical Society

We report results on a precision measurement of the ratio R = uLIUT in deep inelastic electronnucleon scattering in the kinematic range 0.2 ~ x ~ 0.5 and 1 ~ Q 2 ~ 10 ( Ge VIc ) 2 • Our results show, for the first time, a clear falloff of R with increasing Q 2 • Our R results are in agreement with QCD predictions only when corrections for target mass effects and some additional higher twist effects are included.At small x, the data on R favor structure functions with a large gluon contribution.We also report results on the differences RA -RD and the cross section ratio uA I uD between Fe and Au nuclei and the deuteron.Our results for RA -RD are consistent with zero for all x, Q 2 indicating that possible contributions to R from nuclear higher twist effects and spin-0 constituents in nuclei are not different from those in nucleons.The ratios uA I uD from all recent experiments, at all x, Q 2 values, are now in agreement.

We measured the differences in $R=\frac{{\ensuremath{\sigma}}_{L}}{{\ensuremath{\sigma}}_{T}}$ and the cross-section ratio $\frac{{\ensuremath{\sigma}}^{A}}{{\ensuremath{\sigma}}^{D}}$ in deep-inelastic electron scattering from D, Fe, and Au nuclei in the kinematic range $0.2\ensuremath{\le}x\ensuremath{\le}0.5$ and $1\ensuremath{\le}{Q}^{2}\ensuremath{\le}5$ ${(\mathrm{G}\mathrm{e}\mathrm{v}/\mathit{c})}^{2}$. Our results for ${R}^{A}\ensuremath{-}{R}^{D}$ are consistent with zero for all $x$ and ${Q}^{2}$, indicating that possible contributions to $R$ from nuclear higher-twist effects and spin-0 constituents in nuclei are not different from those in nucleons. The European Muon Collaboration effect is reconfirmed, and the low-$x$ data from all recent experiments, at all ${Q}^{2}$, are now in agreement.

Abstract Dilatometry (SFI) has gained wide acceptance for the characterization of solid‐liquid contents of fats over approximately the past 15 years. In more recent times, wide‐line nuclear magnetic resonance (NMR) has been used for this purpose. Still more recently the differential scanning calorimetry (DSC) technique has been used to determine solid‐liquid contents. These three techniques were used to determine the properties of seven fats and oils which represent a cross section of commercially available materials. These products were blended into 14 different compositions and the solid‐liquid contents were determined by the three methods. A comparison is made on the results obtained on the various samples by SFI, NMR and DSC techniques. The results of each procedure are compared according to fat composition.

We present the general properties of multihadron final states produced by ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at center-of-mass energies from 52 to 57 GeV in the AMY detector at the KEK collider TRISTAN. Global shape, inclusive charged-particle, and particle-flow distributions are presented. Our measurements are compared with QCD+fragmentation models that use either leading-logarithmic parton-shower evolution or QCD matrix elements at the parton level, and either string or cluster fragmentation for hadronization.

We report new results on a precision measurement of the ratio $R=\frac{{\ensuremath{\sigma}}_{L}}{{\ensuremath{\sigma}}_{T}}$ and the structure function ${F}_{2}$ for deep-inelastic electron-nucleon scattering in the kinematic range $0.2\ensuremath{\le}x\ensuremath{\le}0.5$ and $1\ensuremath{\le}{Q}^{2}\ensuremath{\le}10$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$. Our results show, for the first time, a clear falloff of $R$ with increasing ${Q}^{2}$. Our $R$ and ${F}_{2}$ results are in good agreement with QCD predictions only when corrections for target-mass effects are included.

Electroproduction of the $\ensuremath{\Delta}$ isobar in C and Fe has been studied for incident electrons with energies between 0.6 and 1.6 GeV. A longitudinal-transverse decomposition of the inclusive cross section has been made for ${q}_{\ensuremath{\mu}}^{2}=0.1$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$. The residual longitudinal cross sections measured do not provide the additional strength needed above the quasifree region to satisfy the Coulomb sum rule. The transverse cross sections are in good agreement with data from photoabsorption.

ULYSSES is a Python package that calculates the baryon asymmetry produced from leptogenesis in the context of a type-I seesaw mechanism. In this release, the new features include code which solves the Boltzmann equations for low-scale leptogenesis; the complete Boltzmann equations for thermal leptogenesis applying proper quantum statistics without assuming kinetic equilibrium of the right-handed neutrinos; and, primordial black hole-induced leptogenesis. ULYSSES version 2 has the added functionality of a pre-provided script for a two-dimensional grid scan of the parameter space. As before, the emphasis of the code is on user flexibility, rapid evaluation and is publicly available at https://github.com/earlyuniverse/ulysses.

We present results of an experimental study of e+e−+ hadrons in the kinematic regime for which the process is interpreted as hadron production in collisions of almost-real photons. The data sample corresponds to an integrated luminosity of 27.5 pb− and covers center-of-mass energies from 55 to 61.4 GeV. We observe more events than expected from the incoherent sum of quark-parton and vector-meson-dominance models, and we give a quantitative explanation of the excess by including the hard scattering of the hadronic constituents of the photons calculated with QCD.

The differential cross section for the reaction H2(γ,p)n has been measured at several center-of-mass angles ranging from 50° to 143° for photon energies between 0.8 and 1.8 GeV. The experiment was performed at the SLAC-NPAS facility with the use of the 1.6 GeV/c spectrometer to detect the high energy protons produced by a bremsstrahlung beam directed at a liquid deuterium target. Contributions from concurrent disintegration by the residual electron beam were determined by measuring the proton yield without the Cu photon radiator. At angles not very far from 90°, the energy dependence of the cross sections is consistent with predictions of scaling using counting rules for constituent quarks. At least one theoretical calculation based on a meson-baryon picture of the reaction is able to reproduce the magnitude and energy dependence of the 90° cross section. The angular distribution exhibits a large enhancement at backward angles at the higher energies.Received 7 May 1993DOI:https://doi.org/10.1103/PhysRevC.48.1864©1993 American Physical Society

We present the charged-particle multiplicity distributions for ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at center-of-mass energies from 50 to 61.4 GeV. The results are based on a data sample corresponding to a total integrated luminosity of 30 ${\mathrm{pb}}^{\ensuremath{-}1}$ obtained with the AMY detector at the KEK storage ring TRISTAN. The charged-particle multiplicity distributions deviate significantly from the modified Poisson and pair Poisson distributions, but follow Koba-Nielsen-Olesen scaling and are well reproduced by the LUND parton-shower model.

We present cross section measurements for inclusive jet production in almost-real photon-photon interactions at TRISTAN using the AMY detector. The results are compared with leading-order QCD calculations for different parameterizations of the parton density in the photon.

The photon structure function F2 has been measured at average Q2 values of 73,160 and 390 (GeVc)2. We compare the x dependence of the Q2 = 73 (GeVc)2 data with theoretical expectations based on QCD. In addition we present results on the Q2 evolution of the structure function for the intermediate x range (0.3⩽ x ⩽0.8). The results are consistent with QCD.

We report measurements of the proton elastic form factors, GEp and GMp, extracted from electron scattering in the range 1⩽Q2⩽3(GeV/c)2. The uncertainties are <15% in GEp and <3% in GMp. The values of GEp are larger than indicated by most theoretical parameterizations, The ratio of Pauli and Dirac form factors, Q2F2p/F1p, is lower and demonstrates less Q2 dependence than most of these parameterizations. Comparisons are made to theoretical models, including those based on perturbative QCD and vector-meson dominance.

In August 2023, IT experts and scientists came together for a workshop to discuss the possibilities of building a computer cluster fully on renewable energies, as a test-case at Havana University in Cuba. The discussion covered the scientific needs for a computer cluster for particle physics at the InSTEC institute at Havana University, the possibilities to use solar energy, new developments in computing technologies, and computer cluster operation as well as operational needs for computing in particle physics. This computer cluster on renewable energies at the InSTEC institute is seen as a prototype for a large-scale computer cluster on renewable energies for scientific computing in the Caribbean, hosted in Cuba. The project is called "Humboldt Highway", to remember Alexander von Humboldt's achievements in bringing cultures of the American and European continents closer together by exchange and travel. In this spirit, we propose a project that enables and intensifies the scientific exchange between research laboratories and universities in Europe and the Caribbean, in particular Cuba.

Three-jet events produced in ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ annihilations are used to provide comparisons between quark and gluon jets. Differences between quark-induced and gluon-induced jets are observed. Quark jets tend to have a more tightly collimated structure than gluon jets, which is reflected in the concentration of a larger fraction of the jet's energy near the jet axis.

The ratio $R$ of the total cross section for ${e}^{+}{e}^{\ensuremath{-}}$ annihilation into hadrons to the lowest-order QED cross section for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ has been measured for center-of-mass energies ranging from 50 to 61.4 GeV. If we allow for an overall shift of ---4.9%, about 1.5 times our estimated normalization error, the results are consistent with the standard-model predictions.

The ATLAS experiment at CERN’s LHC stores detector and simulation data in raw and derived data formats across more than 150 Grid sites world-wide, currently in total about 200PB on disk and 250PB on tape. Data have different access characteristics due to various computational workflows, and can be accessed from different media, such as remote I/O, disk cache on hard disk drives or SSDs. Also, larger data centers provide the majority of offline storage capability via tape systems. For the HighLuminosity LHC (HL-LHC), the estimated data storage requirements are several factors bigger than the present forecast of available resources, based on a flat budget assumption. On the computing side, ATLAS Distributed Computing was very successful in the last years with high performance and high throughput computing integration and in using opportunistic computing resources for the Monte Carlo simulation. On the other hand, equivalent opportunistic storage does not exist. ATLAS started the Data Carousel project to increase the usage of less expensive storage, i.e. tapes or even commercial storage, so it is not limited to tape technologies exclusively. Data Carousel orchestrates data processing between workload management, data management, and storage services with the bulk data resident on offline storage. The processing is executed by staging and promptly processing a sliding window of inputs onto faster buffer storage, such that only a small percentage of input data are available at any one time. With this project, we aim to demonstrate that this is the natural way to dramatically reduce our storage cost. The first phase of the project was started in the fall of 2018 and was related to I/O tests of the sites archiving systems. Phase II now requires a tight integration of the workload and data management systems. Additionally, the Data Carousel studies the feasibility to run multiple computing workflows from tape. The project is progressing very well and the results presented in this document will be used before the LHC Run 3.

The climate crisis and the degradation of the world's ecosystems require humanity to take immediate action. The international scientific community has a responsibility to limit the negative environmental impacts of basic research. The HECAP+ communities (High Energy Physics, Cosmology, Astroparticle Physics, and Hadron and Nuclear Physics) make use of common and similar experimental infrastructure, such as accelerators and observatories, and rely similarly on the processing of big data. Our communities therefore face similar challenges to improving the sustainability of our research. This document aims to reflect on the environmental impacts of our work practices and research infrastructure, to highlight best practice, to make recommendations for positive changes, and to identify the opportunities and challenges that such changes present for wider aspects of social responsibility.

Searches for the pair production of the supersymmetric partner particles of leptons, quarks, and non-minimal Higgs have been made in e +e − annihilations at center-of-mass energies between 50 and 60.8 GeV using the AMY detector at TRISTAN. No evidence for their existence is observed and 95% CL mass limits are presented.

By studying ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ annihilations in the center-of-mass energy range between 50 and 60.8 GeV, we have established a 95%-confidence-level lower limit on the mass of a fourth-generation charge -(1/3 quark b' of 27.2 GeV. In contrast with all previous searches, this limit has been obtained through consideration of the decay processes b'\ensuremath{\rightarrow}b\ensuremath{\gamma} and b'\ensuremath{\rightarrow}bg aswell as b'\ensuremath{\rightarrow}${\mathrm{cW}}^{\mathrm{\ensuremath{-}}}$. For the cases where any one of the three decay modes dominates, we obtain higher mass limits.

The forward-backward asymmetry of quarks produced in ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ annihilations, summed over all flavors, is measured at \ensuremath{\surd}s between 50 and 60.8 GeV. Methods of determining the charge direction of jet pairs are discussed. The asymmetry is found to agree with the five-flavor standard model.

We report on a search for the pair production of leptoquarks and colored leptons in e+e− annihilations t center-of-mass energies from 50 to 60.8 GeV, using the AMY detector at TRISTAN. No evidence for such particles is found and 95% CL mass limits are given.

The Piz Daint Cray XC30 HPC system at CSCS, the Swiss National Supercomputing centre, was the highest ranked European system on TOP500 in 2014, also featuring GPU accelerators. Event generation and detector simulation for the ATLAS experiment have been enabled for this machine. We report on the technical solutions, performance, HPC policy challenges and possible future opportunities for HEP on extreme HPC systems. In particular a custom made integration to the ATLAS job submission system has been developed via the Advanced Resource Connector (ARC) middleware. Furthermore, a partial GPU acceleration of the Geant4 detector simulations has been implemented.

The outcomes of "the future of UAS: standards, regulations and operational experiences" workshop, held on the 7 -8 December 2006, in Brisbane, Queensland, Australia. The goal of the workshop was to identify recent international activities in the unmanned airborne systems (UAS) airspace integration problem. The workshop attracted a broad cross-section of the UAS community, including: airspace and safety regulators, developers, operators, and researchers. The three themes of discussion were: progress in the development of standards and regulations; lessons learnt from recent operations; and advances in new technologies. This summarises the activities of the workshop and explores the important outcomes and trends as perceived by these authors.

Using e+e− annihilation events accumulated with the AMY detector at the TRISTAN collider, we have studied the Bose-Einstein correlations in the distributions of like-sign charged tracks. As reference samples we used the opposite-sign charged track pairs and mixed pairs, which are like-sign pairs synthesized from tracks belonging to different events. The results of the different reference samples give approximately 0.45 for the correlation strength and approximately 0.65 fm for the source size. Previous measurements of these parameters in e+e− annihilation at energies from CESR to LEP show remarkably flat dependence on s. Our results conform well with this picture.

We report results of a study of four-lepton final states produced in e+e− collisions at center-of-mass energies from 50 to 61.4 GeV using the AMY detector at the TRISTAN collider. For the cases where two or three charged tracks are produced at large angles relative to the beam direction, the cross sections agree with QED. However, we observe an excess of e+e−→e+e−μ+μ− events with four tracks at wide angles and with dimuon mass less than 1.0 GeV/c2.

We present a study of the third moment of the inclusive momentum distribution of particles within jets produced by e+ e- annihilation at TRISTAN. In this analysis, the QCD coupling strength αs is determined by fits to the prediction of the Next-to-Leading Logarithm Parton-Shower model. The measured value of αs(57.9 GeV) = 0.134-0.005+0.006.

A search for unstable heavy neutral leptons has been made at center-of-mass energies from 50 to 60.8 GeV with the AMY detector at the KEK Storage ring TRISTAN. The neutral leptons are assumed to decay via mixing to electrons and muons. Events with two leptons were searched for. No evidence for their existence was found. Limits in the mass range \ensuremath{\le}28.1 GeV/${c}^{2}$ and mixing-parameter range 9\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$\ensuremath{\le}\ensuremath{\Vert}${U}_{\mathrm{lL}}$${\ensuremath{\Vert}}^{2}$\ensuremath{\le}1 are presented for Dirac- and Majorana-type neutrinos.

With data corresponding to 142 pb−1 accumulated at s = 57.8 GeV by the AMY detector at TRISTAN we measure the cross section of the reactions e+e− → μ+μ− and e+e− → τ+τ− and the symmetry in the angular distributions. For the lowest order cross section we obtain σμμ = 27.54 ± 0.65 ± 0.95 pb and σττ = 28.27 ± 0.87 ± 0.69 pb, and for the forward-backward asymmetry, Aμμ = 0.303 ± 0.027 ± 0.008 and Aττ = −0.291 ± 0.040 ± 0.019. These measurements agree with the standard model. Assuming e−μ−τ univrsality we extract the vector and axial coupling constants | gν| = 0.00 ± 0.09 and |gA| = 0.476 ± 0.024. A fit of data to composite models places lower bounds (95% confidence level) on the compositeness scale of 2–4 TeV.

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.

This paper presents a new framework for Multi-Objective Flight Management of Unmanned Aerial Systems (UAS), operating in partially known environments, where planning time constraints are present.During UAS operations, civilian UAS may have multiple objectives to meet including: platform safety; minimizing fuel, time, distance; and minimizing deviation from the current path.The planning layers within the framework use multi-objective optimization to converge to a solution which better reflects overall mission requirements.The solution must be generated within the available decision window, else the UAS must enter a safety state; this potentially limits mission efficiency.Local or short range planning at low altitudes requires the classification of terrain and infrastructure in proximity as potential obstacles.The potential increase in the number of obstacles present further reduces the decision window in comparison to high altitude flight.A novel FlightManagement System (FMS) has been incorporated within the framework to moderate the time available to the environment abstraction, path and trajectory planning layers for more efficient use of the available decision window.Enabling the FMS during simulation increased the optimality of the output trajectory on systems with sufficient computational power to run the algorithm in real time.Conversely, the FMS found sub-optimal solutions for the system with insufficient computational capability once the objective utility threshold was decreased from 0.95 to 0.85.This allowed the UAS to continue operations without having to resort to entering a safe state.

The climate crisis and the degradation of the world's ecosystems require humanity to take immediate action. The international scientific community has a responsibility to limit the negative environmental impacts of basic research. The HECAP+ communities (High Energy Physics, Cosmology, Astroparticle Physics, and Hadron and Nuclear Physics) make use of common and similar experimental infrastructure, such as accelerators and observatories, and rely similarly on the processing of big data. Our communities therefore face similar challenges to improving the sustainability of our research. This document aims to reflect on the environmental impacts of our work practices and research infrastructure, to highlight best practice, to make recommendations for positive changes, and to identify the opportunities and challenges that such changes present for wider aspects of social responsibility.

Abstract Keloids are a severe form of scarring for which the underlying mechanisms are poorly understood, and treatment options are limited or inconsistent. While biomechanical forces are potential drivers of keloid scarring, the direct cellular responses to mechanical cues have yet to be defined. The aim of this study was to examine the distinct responses of normal dermal fibroblasts (NDFs) and keloid-derived fibroblasts (KDFs) to changes in extracellular matrix (ECM) stiffness. When cultured on hydrogels mimicking the elasticity of normal or scarred skin, KDFs displayed greater stiffness-dependent increases in cell spreading, F-actin stress fibre formation, and focal adhesion assembly. Elevated acto-myosin contractility in KDFs disrupted the normal mechanical regulation of ECM remodelling, leading to constitutive collagen and fibronectin deposition. Transcriptional profiling identified mechanically-regulated pathways in NDFs and KDFs, including the actin cytoskeleton, Hippo signalling, and autophagy. Further analysis of the autophagy pathway revealed that autophagic flux was intact in both fibroblast populations and depended on acto-myosin contractility. However, KDFs displayed marked changes in lysosome organisation and an increase in lysosomal exocytosis, which was mediated by acto-myosin contractility. Together, these findings demonstrate that KDFs possess an intrinsic increase in cytoskeletal tension, which heightens the response to ECM mechanics and promotes lysosomal exocytosis.

Evidence is presented for local compensation of transverse momentum in $\mathrm{pp}$ collisions at 200 and 300 GeV/c. We compare the data with a model which contains no dynamical transverse-momentum correlations. These data are used to determine a lower bound on the slope of the Pomeranchuk trajectory.

Automated calibration of the ATLAS detector subsystems (like MDT and RPC chambers) are being performed at remote sites, called Remote Calibration Centers. The calibration data for the assigned part of the detector are being processed at these centers and send the result back to CERN for general use in reconstruction and analysis. In this work, we present the recent developments in data discovery mechanism and integration of Ganga as a backend which allows for the specification, submission, bookkeeping and post processing of calibration tasks on a wide set of available heterogeneous resources at remote centers.

Using 773 muons found in hadronic events from 142 ${\mathrm{pb}}^{\ensuremath{-}1}$ of data at a c.m. energy of 57.8 GeV, we extract the cross section and forward-backward charge asymmetry for the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}b\overline{b}$ process, and the heavy quark fragmentation function parameters for the Peterson model. For the analysis of the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}b\overline{b}$ process, we use a method in which the behavior of the $c$ quark and lighter quarks is assumed, with only that of the $b$ quark left indeterminate. The cross section and asymmetry for ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}b\overline{b}$ are found to be ${R}_{b} = 0.57 \ifmmode\pm\else\textpm\fi{} 0.06(\mathrm{stat}) \ifmmode\pm\else\textpm\fi{} 0.08(\mathrm{syst})$ and ${A}_{b} = \ensuremath{-}0.59 \ifmmode\pm\else\textpm\fi{} 0.09 \ifmmode\pm\else\textpm\fi{} 0.09$, respectively. They are consistent with the standard model predictions. For the study of the fragmentation function we use the variable $〈{x}_{E}〉$, the fraction of the beam energy carried by the heavy hadrons. We obtain ${〈{x}_{E}〉}_{c}={0.56}_{\ensuremath{-}0.05\ensuremath{-}0.03}^{+0.04+0.03}$ and ${〈{x}_{E}〉}_{b}={0.65}_{\ensuremath{-}0.04\ensuremath{-}0.06}^{+0.06+0.05}$, respectively. These are in good agreement with previously measured values.

The results of the tests of a prototype ionization sampling calorimeter are presented. Using proportional chmbers interleaved with lead and sampling every 0.68 radiation length, we found an energy resolution of 24%/√E. Measurements of position resolution, lateral shower developent, and hadron rejection are discussed.

The process of cutting squares from rectangles described by D. G. Ball in the June 1974 Gazette , and its connection with continued fractions given by Professor Goodstein in Mathematical note 3359 (December 1974), has an interesting application to electrical circuits.

Searches for the pair production of the supersymmetric partner particles of leptons, quarks, and non-minimal Higgs have been made in e +e − annihilations at center-of-mass energies between 50 and 60.8 GeV using the AMY detector at TRISTAN. No evidence for their existence is observed and 95% CL mass limits are presented.

Following the outbreak of the COVID–19 pandemic, the ATLAS experiment considered how it could most efficiently contribute using its distributed computing resources. After considering many suggestions, examining several potential projects and following the advice of the CERN COVID Task Force, it was decided to engage in the Folding@Home initiative, which provides payloads that perform protein folding simulations. This paper describes how ATLAS made a significant contribution to this project over the summer of 2020.

We report on a measurement of the forward-backward charge asymmetry in ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}q\overline{q}$ at KEK TRISTAN, where the asymmetry is near maximum. We sum over all flavors and measure the asymmetry by determining the charge of the quark jets. In addition we exploit flavor dependencies in the jet charge determination to enhance the contributions of certain flavors. This provides a check on the asymmetries of individual flavors. The measurement agrees with the standard model expectations.

We report preliminary results on the nuclear dependence of R = σL/σT in the deep inelastic electron scattering from deuterium, iron, and gold nuclei. In the x, Q2 range of 0.2 ⩽ x ⩽ 0.5 and 1 ⩽ Q2 ⩽ 5 (GeV/c)2, the average RFe − RD is 0.03 ± 0.02 (stat) ± 0.06 (syst); the final systematic errors are expected to be reduced to ± 0.03. The results indicate that there are no significant spin-0 constituents or higher twist effects in nuclei as compared to free nucleons. Models for the EMC effect with significant nuclear dependence of R are ruled out. The discrepancy, at low x, between CERN and SLAC results for the cross section ratio σFe/σD cannot be attributed to a nuclear dependence of R as suggested by some authors. The kinematic variation of RD with x and Q2 in the SLAC energy is in agreement with the predictions of QCD with the addition of target mass effects.

We report on measurements of the total cross section for e+e−→γγ for center-of-mass energies between 57.4 and 59.5 GeV, using the AMY detector at the TRISTAN collider. We set new limits on the production of a possible new s-channel resonance decaying into photon pairs.

We summarize the R&D results for the Upgraded Plug Hadron Calorimeter using Tile/Fiber technology. The transverse uniformity of the response of the tiles as a function of fiber groove depth and the position of the fiber within the groove is discussed. We compare the light yield and transverse uniformity of the response of megatiles vs individual tiles. We also present the results of a study of the light yield of tiles as a function of their size.

We present a study of differential two jet ratios in multi-hadronic final states produced by e+e− annihilation in the AMY detector at TRISTAN. The data are compared to the predictions of the next-to-leading logarithm parton-shower (NLL PS) Monte Carlo and the O(αs2) matrix element QCD models. We determine the strong coupling strength αs(57.3 GeV) = 0.130 ± 0.006.

The ATLAS production system provides the infrastructure to process millions of events collected during the LHC Run 1 and the first two years of Run 2 using grid, clouds and high performance computing. We address in this contribution the strategies and improvements that have been implemented to the production system for optimal performance and to achieve the highest efficiency of available resources from operational perspective. We focus on the recent developments.

Parameters common to all reactors in which parallel process channels are arranged in a symmetrical lattice in a cylindrical core are shown on a chart. For lattice shells that are not squares or equilateral triangles, the designer can compute the equivalent square lattice area and then use the chart directly. (A.C.)

Results of a search for the pair production of charged heavy leptons in e + e − annihilations over the center-of-mass energy range of 50 to 60.8 GeV are reported. We assume that the leptons are of the sequential type but have allowed for the case where the associated neutrino might be massive. Separate searches for evidence for decays to hadronic and leptonic final states, searches specialized for the case where the charged lepton and its associated neutrino are close in mass, and a search for stable heavy leptons have uncovered no evidence for the production of such particles at these energies. Mass limits for heavy leptons and their associated neutrinos are determined for a range of hadronic and leptonic decay branching fractions. A sequential charged heavy lepton with mass between 12.6 and 29.6 GeV/c 2 and with massless neutrino is excluded at the 95% confidence level.

A search for the pair production of charged Higgs particles decaying via the H−→τν¯ mode has been made in e+e− annihilations at center-of-mass energies between 50 and 60.8 GeV using the AMY detector at the KEK collider TRISTAN. No evidence for their existence is observed and 95%-C.L. mass limits are presented. The result has been interpreted in terms of the tanβ parameter in the Higgs sector.Received 27 February 1990DOI:https://doi.org/10.1103/PhysRevD.42.949©1990 American Physical Society

We have measured the azimuthal correlation of hadrons produced in ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ annihilations at \ensuremath{\surd}s =58 GeV. In perturbative QCD these correlations are sensitive to the interference between soft gluons emitted at large angles with respect to the event axis. However, Monte carlo calculations incorporating QCD-inspired hadronization models in which the correlation of interjet particles is treated in a phenomenological manner describe the data well. We also observe that angular ordering of the parton showering in the lund Monte Carlo program improves the agreement with the data.