547 research outputs found
Training Deep 3D Convolutional Neural Networks to Extract BSM Physics Parameters Directly from HEP Data: a Proof-of-Concept Study Using Monte Carlo Simulations
We report on a novel application of computer vision techniques to extract
beyond the Standard Model (BSM) parameters directly from high energy physics
(HEP) flavor data. We develop a method of transforming angular and kinematic
distributions into "quasi-images" that can be used to train a convolutional
neural network to perform regression tasks, similar to fitting. This contrasts
with the usual classification functions performed using ML/AI in HEP. As a
proof-of-concept, we train a 34-layer Residual Neural Network to regress on
these images and determine the Wilson Coefficient in MC (Monte Carlo)
simulations of decays. The technique
described here can be generalized and may find applicability across various HEP
experiments and elsewhere
Measurement of the cross section with the CMD-3 detector at the VEPP-2000 collider
The process has been studied in the
center-of-mass energy range from 1500 to 2000\,MeV using a data sample of 23
pb collected with the CMD-3 detector at the VEPP-2000 collider.
Using about 24000 selected events, the cross
section has been measured with a systematic uncertainty decreasing from 11.7\%
at 1500-1600\,MeV to 6.1\% above 1800\,MeV. A preliminary study of
production dynamics has been performed
Study of the process in the c.m. energy range from threshold to 2 GeV with the CMD-3 detector
Using a data sample of 6.8 pb collected with the CMD-3 detector at the
VEPP-2000 collider we select about 2700 events of the process and measure its cross section at 12 energy ponts with about
6\% systematic uncertainty. From the angular distribution of produced nucleons
we obtain the ratio
Machine Learning for New Physics Searches in B → K*0µ+µ− Decays
We report the status of a neural network regression model trained to extract new physics (NP) parameters in Monte Carlo (MC) simulation data. We utilize a new EvtGen NP MC generator to generate B → K*0µ+µ− events according to the deviation of the Wilson Coefficient C9 from its SM value, δC9. We train a three-dimensional ResNet regression model, using images built from the angular observables and the invariant mass of the di-muon system, to extract values of δ
C9 directly from the MC data samples. This work is intended for future analyses at the Belle II experiment but may also find applicability at other experiments
Measurement of the Pion Form Factor in the Energy Range 1.04-1.38 GeV with the CMD-2 Detector
The cross section for the process is measured in the
c.m. energy range 1.04-1.38 GeV from 995 000 selected collinear events
including 860000 events, 82000 events, and 33000
events. The systematic and statistical errors of measuring the
pion form factor are equal to 1.2-4.2 and 5-13%, respectively.Comment: 5 pages, 2 figure
CsI(Tl) Pulse Shape Discrimination with the Belle II Electromagnetic Calorimeter as a Novel Method to Improve Particle Identification at Electron-Positron Colliders
This paper describes the implementation and performance of CsI(Tl) pulse
shape discrimination for the Belle II electromagnetic calorimeter, representing
the first application of CsI(Tl) pulse shape discrimination for particle
identification at an electron-positron collider. The pulse shape
characterization algorithms applied by the Belle II calorimeter are described.
Control samples of , , , and are
used to demonstrate the significant insight into the secondary particle
composition of calorimeter clusters that is provided by CsI(Tl) pulse shape
discrimination. Comparisons with simulation are presented and provide further
validation for newly developed CsI(Tl) scintillation response simulation
techniques, which when incorporated with GEANT4 simulations allow the particle
dependent scintillation response of CsI(Tl) to be modelled. Comparisons between
data and simulation also demonstrate that pulse shape discrimination can be a
new tool to identify sources of improvement in the simulation of hadronic
interactions in materials. The efficiency and photon-as-hadron
fake-rate of a multivariate classifier that is trained to use pulse shape
discrimination is presented and comparisons are made to a shower-shape based
approach. CsI(Tl) pulse shape discrimination is shown to reduce the
photon-as-hadron fake-rate by over a factor of 3 at photon energies of 0.2 GeV
and over a factor 10 at photon energies of 1 GeV
Precision Measurement of KS Meson Lifetime with the KLOE detector
Using a large sample of pure, slow, short lived K0 mesons collected with KLOE
detector at DaFne, we have measured the KS lifetime. From a fit to the proper
time distribution we find tau = (89.562 +- 0.029_stat +- 0.043_syst) ps. This
is the most precise measurement today in good agreement with the world average
derived from previous measurements. We observe no dependence of the lifetime on
the direction of the Ks.Comment: 5 pages, 7 figure
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