Searching for dark matter via mono-ZZ boson production at the ILC

High energy colliders provide a new unique way to determine the microscopic properties of the dark matter (DM). Weakly interacting massive particles (WIMPs) are widely considered as one of the best DM candidates. It is usually assumed that the WIMP couples to the SM sector through its interactions with quarks and leptons. In this paper, we investigate the DM pair production associated with a $Z$ boson in an effective field theory framework at the International Linear Collider (ILC), which can be used to study the interactions between the DM and leptons. For illustrative purposes, we present the integrated and differential cross sections for the $e^+ e^- \rightarrow \chi \bar{\chi} Z$ process, where the $Z$ boson is radiated from the initial state electron or positron. Meanwhile, we analyze the neutrino pair production in association with a $Z$ boson as the SM background.Comment: 12 pages, 5 figure

An information-theoretic analysis of control and filtering limitations by the I-MMSE relationships

Fundamental limitations in control and filtering, as the trade-offs between the pursuit of performance and the constraints in the design, have been providing guidelines to the practitioners for the design of controllers and filters in a broad range of applications. Some classical control and filtering trade-offs include Bode's sensitivity integral or the waterbed effect in control and the minimum mean-square error in estimation. By modeling control and filtering systems as noisy communication channels, information-theoretic metrics, such as total information (rate), data transmission rate, and differential entropy (rate) difference, can be also utilized to characterize and quantify the fundamental limitations. Previously, complex analysis and the information-theoretic method based on (differential) entropy are two primal tools for calculating and studying these trade-off metrics. However, both methods can only handle a specific type of systems and are not general enough. In this dissertation, by resorting to the I-MMSE (mutual information - minimum mean-square error) relationships, a comprehensive and estimation-based information-theoretic method is proposed to uniformly calculate and analyze total information (rate), i.e., the mutual information (rate) between transmitted message and channel output, or equivalently, the directed information (rate) from channel input to output, as a trade-off metric that captures the fundamental limitations of numerous control and filtering systems in continuous-time, discrete-time, and infinite-dimensional scenarios. In the continuous-time scenario, with the aid of continuous-time I-MMSE relationships and optimal filtering techniques, we relate total information (rate) to the noise sensitivity trade-offs, (average) performance cost, and lowest achievable mean-square estimation error of various continuous-time control and filtering systems in LTI (linear time-invariant), LTV (linear time-varying), and nonlinear forms. In the discrete-time scenario, we first derive the I-MMSE relationships of discrete-time additive white Gaussian channels with and without feedback. With these relationships and optimal filtering techniques, we then revisit and extend the trade-off properties and interpretations of total information (rate) in discrete-time LTI, LTV, and nonlinear control and filtering systems. Lastly, based on the I-MMSE relationships in abstract Wiener space, a direct and estimation-based scheme is proposed to calculate the total information (rate) of infinite-dimensional control and filtering systems under additive arbitrary Gaussian noise. By applying this scheme to the finite-dimensional systems, we not only recover some well-established fundamental limitations in the control and filtering systems subject to white Gaussian noise, but provide a direct scheme to calculate and study the total information (rate) in some complicated and rarely investigated systems under colored Gaussian noise.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2024-09-16 without embargo termsThe student, Neng Wan, accepted the attached license on 2024-01-03 at 20:00.The student, Neng Wan, submitted this Dissertation for approval on 2024-01-03 at 20:04.This Dissertation was approved for publication on 2024-01-09 at 14:20.DSpace SAF Submission Ingestion Package generated from Vireo submission #20191 on 2024-09-16 at 00:32:5

An information-theoretic analysis of control and filtering limitations by the I-MMSE relationships

Fundamental limitations in control and filtering, as the trade-offs between the pursuit of performance and the constraints in the design, have been providing guidelines to the practitioners for the design of controllers and filters in a broad range of applications. Some classical control and filtering trade-offs include Bode's sensitivity integral or the waterbed effect in control and the minimum mean-square error in estimation. By modeling control and filtering systems as noisy communication channels, information-theoretic metrics, such as total information (rate), data transmission rate, and differential entropy (rate) difference, can be also utilized to characterize and quantify the fundamental limitations. Previously, complex analysis and the information-theoretic method based on (differential) entropy are two primal tools for calculating and studying these trade-off metrics. However, both methods can only handle a specific type of systems and are not general enough. In this dissertation, by resorting to the I-MMSE (mutual information - minimum mean-square error) relationships, a comprehensive and estimation-based information-theoretic method is proposed to uniformly calculate and analyze total information (rate), i.e., the mutual information (rate) between transmitted message and channel output, or equivalently, the directed information (rate) from channel input to output, as a trade-off metric that captures the fundamental limitations of numerous control and filtering systems in continuous-time, discrete-time, and infinite-dimensional scenarios. In the continuous-time scenario, with the aid of continuous-time I-MMSE relationships and optimal filtering techniques, we relate total information (rate) to the noise sensitivity trade-offs, (average) performance cost, and lowest achievable mean-square estimation error of various continuous-time control and filtering systems in LTI (linear time-invariant), LTV (linear time-varying), and nonlinear forms. In the discrete-time scenario, we first derive the I-MMSE relationships of discrete-time additive white Gaussian channels with and without feedback. With these relationships and optimal filtering techniques, we then revisit and extend the trade-off properties and interpretations of total information (rate) in discrete-time LTI, LTV, and nonlinear control and filtering systems. Lastly, based on the I-MMSE relationships in abstract Wiener space, a direct and estimation-based scheme is proposed to calculate the total information (rate) of infinite-dimensional control and filtering systems under additive arbitrary Gaussian noise. By applying this scheme to the finite-dimensional systems, we not only recover some well-established fundamental limitations in the control and filtering systems subject to white Gaussian noise, but provide a direct scheme to calculate and study the total information (rate) in some complicated and rarely investigated systems under colored Gaussian noise.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2024-09-16 without embargo termsThe student, Neng Wan, accepted the attached license on 2024-01-03 at 20:00.The student, Neng Wan, submitted this Dissertation for approval on 2024-01-03 at 20:04.This Dissertation was approved for publication on 2024-01-09 at 14:20.DSpace SAF Submission Ingestion Package generated from Vireo submission #20191 on 2024-09-16 at 00:32:5

Distribution and bioaccumulation of microcystins in water columns: A systematic investigation into the environmental fate and the risks associated with microcystins in Meiliang Bay, Lake Taihu

For the purpose of understanding the environmental fate of microcystins (MCs) and the potential health risks caused by toxic cyanobacterial blooms in Lake Taihu, a systematic investigation was carried out from February 2005 to January 2006. The distribution of MCs in the water column, and toxin bioaccumulations in aquatic organisms were surveyed. The results suggested that Lake Taihu is heavily polluted during summer months by toxic cyanobacterial blooms (with a maximum biovolume of 6.7 x 10(8) cells/L) and MCs. The maximum concentration of cell-bound toxins was 1.81 mg/g (DW) and the dissolved MCs reached a maximum level of 6.69 mu g/L. Dissolved MCs were always found in the entire water column at all sampling sites throughout the year. Our results emphasized the need for tracking MCs not only in the entire water column but also at the interface between water and sediment. Seasonal changes of MC concentrations in four species of hydrophytes (Eichhornic crassipes, Potamogeton maackianus, Alternanthera philoxeroides and Myriophyllum spicatum) ranged from 129 to 1317, 147 to 1534, 169 to 3945 and 124 to 956 ng/g (DW), respectively. Toxin accumulations in four aquatic species (Carassius auratus auratu, Macrobrachium nipponensis, Bellamya aeruginosa and Cristaria plicata) were also analyzed. Maximum toxin concentrations in the edible organs and non-edible visceral organs ranged from 378 to 730 and 754 to 3629 ng/g (DW), respectively. Based on field studies in Lake Taihu, risk assessments were carried out, taking into account the WHO guidelines and the tolerable daily intake (TDI) for MCs. Our findings suggest that the third largest lake in China poses serious health threats when serving as a source of drinking water and for recreational use. In addition, it is likely to be unsafe to consume aquatic species harvested in Lake Taihu due to the high-concentrations of accumulated MCs. (C) 2007 Elsevier Ltd. All rights reserved.For the purpose of understanding the environmental fate of microcystins (MCs) and the potential health risks caused by toxic cyanobacterial blooms in Lake Taihu, a systematic investigation was carried out from February 2005 to January 2006. The distribution of MCs in the water column, and toxin bioaccumulations in aquatic organisms were surveyed. The results suggested that Lake Taihu is heavily polluted during summer months by toxic cyanobacterial blooms (with a maximum biovolume of 6.7 x 10(8) cells/L) and MCs. The maximum concentration of cell-bound toxins was 1.81 mg/g (DW) and the dissolved MCs reached a maximum level of 6.69 mu g/L. Dissolved MCs were always found in the entire water column at all sampling sites throughout the year. Our results emphasized the need for tracking MCs not only in the entire water column but also at the interface between water and sediment. Seasonal changes of MC concentrations in four species of hydrophytes (Eichhornic crassipes, Potamogeton maackianus, Alternanthera philoxeroides and Myriophyllum spicatum) ranged from 129 to 1317, 147 to 1534, 169 to 3945 and 124 to 956 ng/g (DW), respectively. Toxin accumulations in four aquatic species (Carassius auratus auratu, Macrobrachium nipponensis, Bellamya aeruginosa and Cristaria plicata) were also analyzed. Maximum toxin concentrations in the edible organs and non-edible visceral organs ranged from 378 to 730 and 754 to 3629 ng/g (DW), respectively. Based on field studies in Lake Taihu, risk assessments were carried out, taking into account the WHO guidelines and the tolerable daily intake (TDI) for MCs. Our findings suggest that the third largest lake in China poses serious health threats when serving as a source of drinking water and for recreational use. In addition, it is likely to be unsafe to consume aquatic species harvested in Lake Taihu due to the high-concentrations of accumulated MCs. (C) 2007 Elsevier Ltd. All rights reserved

Safety Embedded Stochastic Optimal Control of Networked Multi-Agent Systems via Barrier States

This paper presents a safe stochastic optimal control method for networked multi-agent systems (MASs) by using barrier states (BaSs) to embed the safety constraints into the system dynamics. The networked multi-agent system (MAS) is factorized into multiple subsystems, each of which is augmented with BaSs for the central agent. The optimal control law is obtained by solving the joint Hamilton-Jacobi-Bellman (HJB) equation on the augmented subsystem, which ensures safety via the boundedness of the BaSs. The BaS-based optimal control method generates safe control actions and also preserves optimality. The safe optimal control solution is ultimately approximated with path integrals. We validate the efficacy of the proposed approach in numerical simulations on a cooperative UAV team in two different scenarios