1,351 research outputs found
New mixing pattern for neutrinos
We propose a new mixing pattern for neutrinos with a nonzero mixing angle
. Under a simple form, it agrees well with current neutrino
oscillation data and displays a number of intriguing features including the
- interchange symmetry , , the
trimaximal mixing |U_{\e 2}|=|U_{\mu 2}|=|U_{\tau 2}|=1/\sqrt{3}, the
self-complementarity relation , together with the
maximal Dirac CP violation as a prediction.Comment: 4 pages, 1 figure. Final version to appear in PR
ParticleNet: Jet Tagging via Particle Clouds
How to represent a jet is at the core of machine learning on jet physics.
Inspired by the notion of point clouds, we propose a new approach that
considers a jet as an unordered set of its constituent particles, effectively a
"particle cloud". Such a particle cloud representation of jets is efficient in
incorporating raw information of jets and also explicitly respects the
permutation symmetry. Based on the particle cloud representation, we propose
ParticleNet, a customized neural network architecture using Dynamic Graph
Convolutional Neural Network for jet tagging problems. The ParticleNet
architecture achieves state-of-the-art performance on two representative jet
tagging benchmarks and is improved significantly over existing methods.Comment: 11 pages, 4 figures; v3: updated to match the version published in
PRD; Code available at https://github.com/hqucms/ParticleNe
Jet tagging in the Lund plane with graph networks
The identification of boosted heavy particles such as top quarks or vector
bosons is one of the key problems arising in experimental studies at the Large
Hadron Collider. In this article, we introduce LundNet, a novel jet tagging
method which relies on graph neural networks and an efficient description of
the radiation patterns within a jet to optimally disentangle signatures of
boosted objects from background events. We apply this framework to a number of
different benchmarks, showing significantly improved performance for top
tagging compared to existing state-of-the-art algorithms. We study the
robustness of the LundNet taggers to non-perturbative and detector effects, and
show how kinematic cuts in the Lund plane can mitigate overfitting of the
neural network to model-dependent contributions. Finally, we consider the
computational complexity of this method and its scaling as a function of
kinematic Lund plane cuts, showing an order of magnitude improvement in speed
over previous graph-based taggers.Comment: 23 pages, 12 figures, code available at
https://github.com/fdreyer/lundne
Probing Triple-W Production and Anomalous WWWW Coupling at the CERN LHC and future 100TeV proton-proton collider
Triple gauge boson production at the LHC can be used to test the robustness
of the Standard Model and provide useful information for VBF di-boson
scattering measurement. Especially, any derivations from SM prediction will
indicate possible new physics. In this paper we present a detailed Monte Carlo
study on measuring WWW production in pure leptonic and semileptonic decays, and
probing anomalous quartic gauge WWWW couplings at the CERN LHC and future
hadron collider, with parton shower and detector simulation effects taken into
account. Apart from cut-based method, multivariate boosted decision tree method
has been exploited for possible improvement. For the leptonic decay channel,
our results show that at the sqrt{s}=8(14)[100] TeV pp collider with integrated
luminosity of 20(100)[3000] fb-1, one can reach a significance of
0.4(1.2)[10]sigma to observe the SM WWW production. For the semileptonic decay
channel, one can have 0.5(2)[14]sigma to observe the SM WWW production. We also
give constraints on relevant Dim-8 anomalous WWWW coupling parameters.Comment: Accepted version by JHE
ParticleNet and its application on CEPC Jet Flavor Tagging
Identification of quark flavor is essential for collider experiments in
high-energy physics, relying on the flavor tagging algorithm. In this study,
using a full simulation of the Circular Electron Positron Collider (CEPC), we
investigated the flavor tagging performance of two different algorithms:
ParticleNet, originally developed at CMS, and LCFIPlus, the current flavor
tagging algorithm employed at CEPC. Compared to LCFIPlus, ParticleNet
significantly enhances flavor tagging performance, resulting in a significant
improvement in benchmark measurement accuracy, i.e., a 36% improvement for
measurement and a 75% improvement for
measurement via W boson decay when CEPC operates as a Higgs factory at the
center-of-mass energy of 240 GeV and integrated luminosity of 5.6 . We
compared the performance of ParticleNet and LCFIPlus at different vertex
detector configurations, observing that the inner radius is the most sensitive
parameter, followed by material budget and spatial resolution
Jet origin identification and measurement of rare hadronic decays of Higgs boson at collider
We propose to identify the jet origin using deep learning tools for
experiments at the high energy frontier, where jet origins are categorized into
5 species of quarks, i.e., , 5 species of anti-quarks, i.e.,
, and gluons. Using simulated physics
events at the Circular Electron Positron Collider and the ParticleNet
algorithm, we quantify the performance of jet origin identification using an
11-dimensional confusion matrix. This matrix exhibits flavor tagging
efficiencies of 91% for and , 80% for and , and 64%
for and quarks, as well as jet charge misidentification rates of
18% for and , 7% for and , and 16% for and
quarks, respectively. We use this method to determine the upper
limits on branching ratios of Higgs rare hadronic decays, specifically for
, , and , as well as for decays via
flavor-changing neutral current, such as , , , . We conclude
that these Higgs decay branching ratios could be measured with typical upper
limits of 0.02%-0.1% at 95% confidence level at CEPC nominal parameters. For
the decay, this upper limit corresponds to three times
the standard model prediction
Effect of Zishen Jiangtang Pill, a Chinese Herbal Product, on Rats with Diabetic Osteoporosis
Diabetic osteoporosis (DO) is a complication of diabetes. Zishen Jiangtang Pill (ZJP) is a Chinese herbal product which has been used in clinic to maintain blood glucose level and bone density for decades. However, the evidence about its mechanism on diabetes and osteoporosis is still unknown. The aim of this study is to investigate therapeutic effect of ZJP on DO in streptozotocin- (STZ-) induced rats. Rats were randomly assigned to 4 groups: one control group (CON), one model group (MOD), and two ZJP treatment groups (1.5 and 3.0 g/kg/d). All rats were treated for 8 weeks. Results showed that ZJP decreased the blood glucose level during OGTT and prevented the changes of FBG and Fins. Similarly, ZJP inhibited the changes of BCa, P, TRACP-5b, CTX-1, BALP, and BGP and the reduction of BMD. In parallel, 1H-NMR metabolomic studies showed that ZJP significantly altered the metabolic fingerprints of blood and urine level. These findings suggest that ZJP can effectively improve glucose metabolism, abnormal bone metabolism, and metabolic disorders in DO rats, which may be a useful alternative medicine for DO therapy
Public interest in distribution and determinants of influenza and pneumonia vaccination during the covid-19 pandemic : An infodemiology and cross-sectional study from china
Background: Following the COVID-19 pandemic, global interest in influenza vaccines and pneumonia vaccines has increased significantly. We aimed to examine public interest in and actual market circulation of influenza and pneumonia vaccines before and after the initial outbreak of COVID-19 and estimate the coverage and determinants of influenza and pneumonia vaccination uptake following the COVID-19 pandemic. Methods: We obtained search volume data for vaccines using the Baidu search index and collected the numbers of vaccines issued from the National Institutes for Food and Drug Control. We also conducted a cross-sectional survey among 3346 adult residents to evaluate the coverage and determinants of influenza and pneumonia vaccination uptake in the Yangtze River delta, China, from 29 January to 4 February 2021. Results: Public searches and the number of vaccines issued for the influenza vaccines and pneumonia vaccines obviously increased after the initial outbreak of COVID-19. In the total sample, 12.5% were vaccinated against influenza, and 21.5% had at least one family member vaccinated against pneumonia. A minority of participants perceived that they were highly or very highly susceptible to influenza (15.9%) and COVID-19 (6.7%). A range of socio-economic factors and perceived susceptibility to COVID-19 were associated with influenza and pneumonia vaccination uptake. Conclusions: Public interest in and issued volumes of influenza and pneumonia vaccines increased nationally following the COVID-19 pandemic. Perceptions of high susceptibility to COVID-19 were associated with the uptake of the influenza and pneumonia vaccines. Targeted interventions were needed to improve vaccination coverage.publishedVersionPeer reviewe
Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV
Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.
Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions
Peer reviewe
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