21 research outputs found
Probing New Physics using top quark polarization in the e+e- -> t \bar{t} process at future Linear Colliders
We investigate the sensitivity to new physics of the process e+e- -> t bar{t}
when the top polarization is analyzed using leptonic final states e+e- -> t
\bar{t} -> l+l- b \bar{b} nu_l \bar{nu}_l. We first show that the kinematical
reconstruction of the complete kinematics is experimentally tractable for this
process. Then we apply the matrix element method to study the sensitivity to
the Vt\bar{t} coupling (V being a vector gauge boson), at the tree level and in
the narrow width approximation. Assuming the ILC baseline configuration,
sqrt{S}=500 GeV, and a luminosity of 500 fb^{-1}, we conclude that this optimal
analysis allows to determine simultaneously the ten form factors that
parameterize the Vt\bar{t} coupling, below the percent level. We also discuss
the effects of the next leading order (NLO) electroweak corrections using the
GRACE program with polarized beams. It is found that the NLO corrections to
different beam polarization lead to significantly different patterns of
contributions.Comment: 14 pages, 4 figures, Proceedings for the TYL-FJPPL workshops on "Top
Physics at ILC
Improving Object Detection in Medical Image Analysis through Multiple Expert Annotators: An Empirical Investigation
The work discusses the use of machine learning algorithms for anomaly
detection in medical image analysis and how the performance of these algorithms
depends on the number of annotators and the quality of labels. To address the
issue of subjectivity in labeling with a single annotator, we introduce a
simple and effective approach that aggregates annotations from multiple
annotators with varying levels of expertise. We then aim to improve the
efficiency of predictive models in abnormal detection tasks by estimating
hidden labels from multiple annotations and using a re-weighted loss function
to improve detection performance. Our method is evaluated on a real-world
medical imaging dataset and outperforms relevant baselines that do not consider
disagreements among annotators.Comment: This is a short version submitted to the Midwest Machine Learning
Symposium (MMLS 2023), Chicago, IL, US
Statistical Analsysis to Evaluate Heavy Metal Pollution in the Air Obatained by Moss Technique in Hanoi and its Surrounding Region
The aim of this paper was the application of statistical analysis including principal component analysis to evaluate heavy metal pollution obtained by moss technique in the air of Ha Noi and its surrounding areas and to evaluate potential pollution sources. The concentrations of 33 heavy metal elements in 27 samples of Barbula Indica moss in the investigated region collected in December of 2016 in the investigated area have been examined using multivariate statistical analysis. Five factors explaining 80% of the total variance were identified and their potential sources have been discussed
Role of clusters in nuclear astrophysics with Cluster Nucleosynthesis Diagram (CND)
The role of nuclear clustering in stellar reactions is discussed, with Cluster Nucleosynthesis Diagram (CND) proposed before, for nucleosynthesis in stellar evolution and explosive stellar phenomena. Special emphasis is placed on α-induced stellar reactions. We report here the first experimental evidence that a cluster resonances dominate the (α,p) stellar reaction cross sections that is crucial for the vp-process in core-collapse supernovae
Coulomb breakup of secondary beams of neutron-rich nuclei
Secondary beams of unstable nuclei with kinetic energies of several hundred MeV per nucleon are produced at, GSI in fragment~ationr eactions followed by in-flight, isot,ope separat'ion. Results of studies of light) neutron-rich nuclei ranging from beryllium to oxygen including halo nuclei are presented. Interaction of the projectiles with lead targets leads to Coulomb breakup mediated t,hrough dipole excitabions into the continuum. Non-resonant excitat,ions near the neutron separat,ion threshold deliver information on ground-stat,e properties such as spect,roscopic factors