2,320 research outputs found
Wave fronts via Fourier series coefficients
Motivated by the product of periodic distributions, we give a new description
of the wave front and the Sobolev-type wave front of a distribution
in terms of Fourier series coefficients.Comment: 10 page
Enhancing the CDF's B physics program with a faster data acquisition system.
The physics program of Run II at the Tevatron includes precision electroweak measurements such as the determination of the top quark and W boson masses; bottom and charm physics including the determination of the B{sub s} and D{sup 0} mixing parameters; studies of the strong interaction; and searches for the Higgs particle, supersymmetric particles, hidden space-time dimensions and quark substructure. All of these measurements benefit from a high-resolution tracking detector. Most of them rely heavily on the efficient identification of heavy flavored B hadrons by detection of displaced secondary vertices, and are enhanced by the capability to trigger on tracks not coming from the primary vertex. This is uniquely provided by CDF's finely-segmented silicon detectors surrounding the interaction region. Thus CDF experiment's physics potential critically depends on the performance of its silicon detectors. The CDF silicon detectors were designed to operate up to 2-3 fb{sup -1} of accumulated pji collisions, with an upgrade planned thereafter. However, the upgrade project was canceled in 2003 and Run II has been extended through 2011, with an expected total delivered integrated luminosity of 12 fb{sup -1} or more. Several preventive measures were taken to keep the original detector operational and maintain its performance. The most important of these are the decrease in the operating temperature of the detector, which reduces the impact of radiation exposure, and measures to minimize damage due to integrated radiation dose, thermal cycles, and wire bond resonance conditions. Despite these measures the detectors operating conditions continue to change with issues arising from radiation damage to the sensors, aging infrastructure and electronics. These, together with the basic challenges posed by the inaccessibility of the detector volume and large number (about 750 thousand) of readout channels, make the silicon detector operations the single most complex and high priority job in the CDF experiment
Identifying boosted new physics with non-isolated leptons
We demonstrate the utility of leptons which fail standard isolation criteria
in searches for new physics at the LHC. Such leptons can arise in any event
containing a highly boosted particle which decays to both leptons and quarks.
We begin by considering multiple extensions to the Standard Model which
primarily lead to events with non-isolated leptons and are therefore missed by
current search strategies. We emphasize the failure of standard isolation
variables to adequately discriminate between signal and SM background for any
value of the isolation cuts. We then introduce a new approach which makes use
of jet substructure techniques to distinguish a broad range of signals from QCD
events. We proceed with a simulated, proof-of-principle search for R-parity
violating supersymmetry to demonstrate both the experimental reach possible
with the use of non-isolated leptons and the utility of new substructure
variables over existing techniquesComment: 15 pages plus references, 11 figures; references adde
Effect of soil particle size on copper availability
This paper deals with the effect of soil particle size on copper availability. Twelve vineyards, (at three depths) all on the territory of the Vojvodina Province, were observed for soil contamination with copper. Soil samples were taken in four locations (5 soil types). The samples were analyzed for total copper and available copper (in EDTA). and sequential extraction was conducted. Correlations between soil particle size and copper fractions were calculated and analyzed. The obtained results indicated that the increase in the portion of smallest soil separates, clay and silt, tended to reduce copper availability, whereas the larger separates tended to increase it. The available fractions, C u e x and C u c a r , were significantly negatively correlated with the content of clay and silt along the entire soil profile of the analyzed vineyards. Simultaneously, these two factions were positively correlated with the content of fine sand, also along the entire soil profile. The results confirmed that, when assessing the extent of soil contamination with copper, soil mechanical composition should be taken into account as an important factor of copper availability
An Extension and Cooperation Mechanism for Heterogeneous Overlay Networks
Part 1: Future Heterogeneous NetworkInternational audienceIn real-world peer-to-peer applications, the scalability of data lookup is heavily affected by network artifacts. A common solution to improve scalability, robustness and security is to increase the local properties of nodes, by clustering them together. This paper presents a framework which allows for the development of distributed applications on top of interconnected overlay network. Here, message routing between overlays is accomplished by using co-located nodes, i.e. nodes belonging to more than one overlay network at the same time. These co-located nodes serve as distributed gateways, enabling the routing of requests across overlays, while keeping overlay maintenance operations local. The protocol has been evaluated via simulations and client deployment, showing that the ability, of reaching the totality of the overlays in a federated configuration can be preserved even with the simplest routing, proving the feasibility of federated overlay configurations
A Backward-Compatible Protocol for Inter-routing over Heterogeneous Overlay Networks
Short paper + posterInternational audienceOverlay networks are logical networks running on the highest level of the OSI stack: they are applicative networks used by millions of users everyday. In many scenarios, it would be desirable for peers belonging to overlays running different protocols to communicate with each other and exchange certain information. However, due to differences in their respective protocols, this communication is often difficult or even impossible to be achieved efficiently, even if the overlays are sharing common objectives and functionalities. In this paper, we address this problem by presenting a new overlay protocol, called OGP (Overlay Gateway Protocol), allowing different existing networks to route messages between each other in a backward-compatible fashion, by making use of specialized peers joined together into a super-overlay. Experimental results on a large scale Grid5000 infrastructure show that having only a small number of nodes running the OGP protocol is sufficient for achieving efficient routing between heterogeneous overlay networks
On-Sensor Data Filtering using Neuromorphic Computing for High Energy Physics Experiments
This work describes the investigation of neuromorphic computing-based spiking
neural network (SNN) models used to filter data from sensor electronics in high
energy physics experiments conducted at the High Luminosity Large Hadron
Collider. We present our approach for developing a compact neuromorphic model
that filters out the sensor data based on the particle's transverse momentum
with the goal of reducing the amount of data being sent to the downstream
electronics. The incoming charge waveforms are converted to streams of
binary-valued events, which are then processed by the SNN. We present our
insights on the various system design choices - from data encoding to optimal
hyperparameters of the training algorithm - for an accurate and compact SNN
optimized for hardware deployment. Our results show that an SNN trained with an
evolutionary algorithm and an optimized set of hyperparameters obtains a signal
efficiency of about 91% with nearly half as many parameters as a deep neural
network.Comment: Manuscript accepted at ICONS'2
Smartpixels: Towards on-sensor inference of charged particle track parameters and uncertainties
The combinatorics of track seeding has long been a computational bottleneck
for triggering and offline computing in High Energy Physics (HEP), and remains
so for the HL-LHC. Next-generation pixel sensors will be sufficiently
fine-grained to determine angular information of the charged particle passing
through from pixel-cluster properties. This detector technology immediately
improves the situation for offline tracking, but any major improvements in
physics reach are unrealized since they are dominated by lowest-level hardware
trigger acceptance. We will demonstrate track angle and hit position
prediction, including errors, using a mixture density network within a single
layer of silicon as well as the progress towards and status of implementing the
neural network in hardware on both FPGAs and ASICs.Comment: 6 pages, 3 figures, submitted to Neural Information Processing
Systems 2023 (NeurIPS
Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV
Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
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