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M. H. L. S. Wang

Publications and source records attributed to M. H. L. S. Wang.

7 recordsLinked to original sources
arXiv2024

A systematic study of projection biases in the Weak Lensing analysis of cosmic shear and the combination of galaxy clustering and galaxy-galaxy lensing

This paper presents the results of a systematic study of projection biases in the Weak Lensing analysis of cosmic shear and the combination of galaxy clustering and galaxy-galaxy lensing using data collected during the first-year of running the Dark Energy Survey experiment. The study uses $Λ$CDM as the cosmological model and two-point correlation functions for the WL analysis. The results in this paper show that, independent of the WL analysis, projection biases of more than $1σ$ exist, and are a function of the position of the true values of the parameters $h$, $n_{s}$, $Ω_{b}$, and $Ω_νh^{2}$ with respect to their prior probabilities. For cosmic shear, and the combination of galaxy clustering and galaxy-galaxy lensing, this study shows that the coverage probability of the $68.27\%$ credible intervals ranges from as high as $93\%$ to as low as $16\%$, and that these credible intervals are inflated, on average, by $29\%$ for cosmic shear and $20\%$ for the combination of galaxy clustering and galaxy-galaxy lensing. The results of the study also show that, in six out of nine tested cases, the reduction in error bars obtained by transforming credible intervals into confidence intervals is equivalent to an increase in the amount of data by a factor of three.

astro-ph.CO↗
arXiv2022

Low-Energy Physics in Neutrino LArTPCs

In this white paper, we outline some of the scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) detectors. Key takeaways are summarized as follows. 1) LArTPCs have unique sensitivity to a range of physics and astrophysics signatures via detection of event features at and below the few tens of MeV range. 2) Low-energy signatures are an integral part of GeV-scale accelerator neutrino interaction final states, and their reconstruction can enhance the oscillation physics sensitivities of LArTPC experiments. 3) BSM signals from accelerator and natural sources also generate diverse signatures in the low-energy range, and reconstruction of these signatures can increase the breadth of BSM scenarios accessible in LArTPC-based searches. 4) Neutrino interaction cross sections and other nuclear physics processes in argon relevant to sub-hundred-MeV LArTPC signatures are poorly understood. Improved theory and experimental measurements are needed. Pion decay-at-rest sources and charged particle and neutron test beams are ideal facilities for experimentally improving this understanding. 5) There are specific calibration needs in the low-energy range, as well as specific needs for control and understanding of radiological and cosmogenic backgrounds. 6) Novel ideas for future LArTPC technology that enhance low-energy capabilities should be explored. These include novel charge enhancement and readout systems, enhanced photon detection, low radioactivity argon, and xenon doping. 7) Low-energy signatures, whether steady-state or part of a supernova burst or larger GeV-scale event topology, have specific triggering, DAQ and reconstruction requirements that must be addressed outside the scope of conventional GeV-scale data collection and analysis pathways.

physics.ins-det↗
arXiv2022

A deep-learning based raw waveform region-of-interest finder for the liquid argon time projection chamber

The liquid argon time projection chamber (LArTPC) detector technology has an excellent capability to measure properties of low-energy neutrinos produced by the sun and supernovae and to look for exotic physics at very low energies. In order to achieve those physics goals, it is crucial to identify and reconstruct signals in the waveforms recorded on each TPC wire. In this paper, we report on a novel algorithm based on a one-dimensional convolutional neural network (CNN) to look for the region-of-interest (ROI) in raw waveforms. We test this algorithm using data from the ArgoNeuT experiment in conjunction with an improved noise mitigation procedure and a more realistic data-driven noise model for simulated events. This deep-learning ROI finder shows promising performance in extracting small signals and gives an efficiency approximately twice that of the traditional algorithm in the low energy region of $\sim$0.03-0.1 MeV. This method offers great potential to explore low-energy physics using LArTPCs.

physics.ins-det↗
arXiv2021

A Systematic Study of Projection Biases in Weak Lensing Analysis

We present a systematic study of projection biases in the weak lensing analysis of the first year of data from the Dark Energy Survey (DES) experiment. In the analysis we used a $Λ$CDM model and three two-point correlation functions. We show that these biases are a consequence of projecting, or marginalizing, over parameters like $h$, $Ω_b$, $n_s$ and $Ω_νh^2$ that are both poorly constrained and correlated with the parameters of interest like $Ω_m$, $σ_8$ and $S_8$. Covering the relevant parameter space we show that the projection biases are a function of where the true values of the poorly constrained parameters lie with respect to the parameter priors. For example, biases in the position of the posteriors can exceed the 1.5$σ$ level if the true values of $h$ and $n_s$ are close to the top of the prior's range and the true values of $Ω_b$ and $Ω_νh^2$ are close to the bottom of the range of their priors. We also show that in some cases the 1D credible intervals can be over-specified by as much as 30% and coverage can be as low as 27%. Finally we estimate these projection biases for the analysis of three and six years worth of DES data.

astro-ph.CO↗
arXiv2009

Top Mass Measurements at the Tevatron

We present the latest measurements of the top quark mass from the Tevatron. The different top decay channels and measurement techniques used for these results are also described. The world average of the top quark mass based on some of these new results combined with previous results is mtop=172.6+-1.4 GeV.

hep-ex↗
arXiv2005

Search for Exotic Baryons in 800 GeV pp (rtarrow) pXiPiX

We report the results of a high-statistics, sensitive search for narrow baryon resonances decaying to $Ξ^-π^-$, $Ξ^-π^+$, $\barΞ^+π^-$, and $\barΞ^+π^+$. The only resonances observed are the well known $Ξ^0(1530)$ and $\bar{Ξ^0}(1530)$. No evidence is found for a state near 1862 MeV, previously reported by NA49\cite{NA49}. At the 95% confidence level, we find the upper limit for the production of a Gaussian enhancement with $σ=7.6$ MeV in the $Ξ^-π^-$ effective mass spectrum to be 0.3% of the number of observed $Ξ^0(1530)\toΞ^-π^+$. We find similarly restrictive upper limits for an enhancement at 1862 MeV in the $Ξ^-π^+$, $\barΞ^+π^-$, and $\barΞ^+π^+$ mass spectra.

hep-ex↗