High energy physics experiments rely heavily on the detailed detector simulation models in many tasks. Running these detailed models typically requires a notable amount of the computing time ...available to the experiments. In this work, we demonstrate a new approach to speed up the simulation of the Time Projection Chamber tracker of the MPD experiment at the NICA accelerator complex. Our method is based on a Generative Adversarial Network – a deep learning technique allowing for implicit estimation of the population distribution for a given set of objects. This approach lets us learn and then sample from the distribution of raw detector responses, conditioned on the parameters of the charged particle tracks. To evaluate the quality of the proposed model, we integrate a prototype into the MPD software stack and demonstrate that it produces high-quality events similar to the detailed simulator, with a speed-up of at least an order of magnitude. The prototype is trained on the responses from the inner part of the detector and, once expanded to the full detector, should be ready for use in physics tasks.
The increasing luminosities of future Large Hadron Collider runs and next generation of collider experiments will require an unprecedented amount of simulated events to be produced. Such large scale ...productions are extremely demanding in terms of computing resources. Thus new approaches to event generation and simulation of detector responses are needed. In LHCb, the accurate simulation of Cherenkov detectors takes a sizeable fraction of CPU time. An alternative approach is described here, when one generates high-level reconstructed observables using a generative neural network to bypass low level details. This network is trained to reproduce the particle species likelihood function values based on the track kinematic parameters and detector occupancy. The fast simulation is trained using real data samples collected by LHCb during run 2. We demonstrate that this approach provides high-fidelity results.
Abstract
The increasing luminosities of future data taking at Large Hadron Collider and next generation collider experiments require an unprecedented amount of simulated events to be produced. Such ...large scale productions demand a significant amount of valuable computing resources. This brings a demand to use new approaches to event generation and simulation of detector responses. In this paper, we discuss the application of generative adversarial networks (GANs) to the simulation of the LHCb experiment events. We emphasize main pitfalls in the application of GANs and study the systematic effects in detail. The presented results are based on the Geant4 simulation of the LHCb Cherenkov detector.
Abstract
Detailed detector simulation models are vital for the successful operation of modern high-energy physics experiments. In most cases, running detailed models requires a significant amount of ...computing resources. It is desired to have approaches that are less resource-intensive. In this work, we demonstrate the applicability of Generative Adversarial Networks (GAN) as a basis for such fast-simulation models for the case of the Time Projection Chamber (TPC) at the MPD detector at the NICA accelerator complex. Our prototype GAN-based model of TPC works faster than the detailed simulation in an order of magnitude without any noticeable drop in the quality of the high-level reconstruction characteristics for the generated data. Approaches with direct and indirect quality metrics optimization are compared.
The paper presents several recent ATLAS results on the analyses of
B
-meson decays into charmonium states. These include the measurements of
B
+
mass and the fractions of
J
/ψ mesons produced in
b
...-hadron decays in
pp
collisions at
s
= 13 TeV in the center of mass system. The measured partial widths and polarizations in
B
c
+
→
J
/ψ
D
s
(*)+
decays and CP-violation parameters in
B
s
0
→
J
/ψϕ decays in
pp
collisions at 7 and 8 TeV in the center of mass system are also presented.
Performance of the Transition Radiation Tracker (TRT) at the ATLAS experiment with argon and krypton gas mixtures was simulated. The efficiency of transition radiation registration, which is ...necessary for electron identification, was estimated along with the electron identification capabilities under such conditions.
Objectives
. The conditions for the effective application of the sharp distillation technique (without a component distributed between the distillate and bottom flows) for the separation of ...quaternary zeotropic mixtures containing components with similar volatilities were determined. The area of energy advantage for the flowsheet based on the preliminary fractionation of the mixture, compared with the flowsheet, the first distillation column of which works based on the indirect separation mode, was identified for an ethyl acetate–benzene–toluene–butyl acetate system. Energy savings of up to 20% were achieved. The direct and indirect distillation modes can become competitive when the point of the original composition is located near single K-surfaces or in a region with a different ratio of distribution coefficients. Sharp distillation is not suitable for the separation of a mixture containing a pair of components exhibiting relative unity volatility with medium boiling points.
Methods
. The mathematical modeling in the Aspen Plus V.10.0 software package was chosen as the research method. The simulation was based on the Wilson local composition equation. The relative errors in the description of the phase equilibrium did not exceed 3%.
Results
. The structure of the vapor–liquid equilibrium diagram and diagram of surfaces of the unit component distribution coefficients were studied for the ethyl acetate–benzene–toluenebutyl acetate and acetone–toluene–butyl acetate–o-xylene systems. Flowsheets based on the sharp, indirect (both systems), or direct (second system) distillation modes were proposed. The distillation process was simulated, and the parameters of the column work were determined (the quality of the substances meets the State Standard requirements of the Russian Federation for minimal energy consumption).
Conclusions
. Recommendations regarding the use of sharp distillation for the separation of quaternary mixtures containing components with similar volatilities were devised.
In the paper, the algebra of
p
(
x
)-circulants over an arbitrary finite field is studied and algorithms of random equiprobable choice of elements in the subset of all invertible
p
(
x
)-circulants ...or in the subset of all
p
(
x
)-circulants with given value of the determinant are constructed. The specific feature of the algorithms under consideration is the minimization of time complexity and of the number of random elements used in the course of work of the algorithms.
In this article, the authors propose using a neural network to optimize the aerodynamic drag of a body in a gas flow. The use of such optimization methods using evolutionary algorithms makes it ...possible to obtain a mathematical model that describes the shape of the aerodynamic profile, which allows the operator to easily change parameters. It is shown that the value of the drag force for a body of optimized shape is lower than the values for bodies of rotation and known profiles taken for comparison. As bodies, we can consider parts of engineering structures in the air flow, parts of vehicles, and bodies located in the air flow in the duct, in particular in the duct of the photo separator. The latter is important from the point of view of neural network photo separation of seeds and grain.
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