Discovery potential for supernova relic neutrinos with slow liquid scintillator detectors

Detection of supernova relic neutrinos could provide key support for our current understanding of stellar and cosmological evolution, and precise measurements of these neutrinos could yield novel insights into the universe. In this paper, we studied the detection potential of supernova relic neutrinos using linear alkyl benzene (LAB) as a slow liquid scintillator. The linear alkyl benzene features good separation of Cherenkov and scintillation lights, thereby providing a new route for particle identification. We further addressed key issues in current experiments, including (1) the charged current background of atmospheric neutrinos in water Cherenkov detectors and (2) the neutral current background of atmospheric neutrinos in typical liquid scintillator detectors. A kiloton-scale LAB detector at Jinping with $\mathcal{O}$(10) years of data could discover supernova relic neutrinos with a sensitivity comparable to that of large-volume water Cherenkov detectors, typical liquid scintillator detectors, and liquid argon detectors.Comment: 9 pages, 6 figure

The evaluation of carbon benefits produced by urban street trees

Urban tree service and urban forestry are important fields that focus on the care and management of trees in urban areas. Urban trees provide numerous benefits around all aspect, including carbon storage, improving air and water qualities. Carbon storage refers to the process of removing carbon dioxide (CO2) from the atmosphere and storing it in various reservoirs, and in this case, in trees and forests. i-Tree is a suite of software tools developed by the United States Forest Service that provides a range of resources for assessing and managing forests. i-Tree Eco is one of the more used tools from iTree suite. It is mainly used for assessing the structure and function of urban forests. In this project, i-Tree Eco is used to process data samples collected from the campus of New Jersey Institute of Technology (NJIT). iTree-Eco provides estimated calculations on multiple aspects. The evaluation will be more focused on the carbon sequestration and carbon storage of each species. The overall objective of this thesis is to evaluate the current and potential carbon benefits produced by the trees of the NJIT campus, as a model of a typical urban campus. There are two sub objectives. One is to analyze the i-Tree package with provided documentation, trying to replicate some of the outputs using new written functions. Second is to analyze the reports generated by i-Tree Eco to making environmental plans

Design, characterization, and sensitivity of the supernova trigger system at Daya Bay

Providing an early warning of galactic supernova explosions from neutrino signals is important in studying supernova dynamics and neutrino physics. A dedicated supernova trigger system has been designed and installed in the data acquisition system at Daya Bay and integrated into the worldwide Supernova Early Warning System (SNEWS). Daya Bay's unique feature of eight identically-designed detectors deployed in three separate experimental halls makes the trigger system naturally robust against cosmogenic backgrounds, enabling a prompt analysis of online triggers and a tight control of the false-alert rate. The trigger system is estimated to be fully sensitive to 1987A-type supernova bursts throughout most of the Milky Way. The significant gain in sensitivity of the eight-detector configuration over a mass-equivalent single detector is also estimated. The experience of this online trigger system is applicable to future projects with spatially distributed detectors.Comment: 8 pages, 6 figures, to be submitted to Astroparticle Physic

Probing dynamics of dark energy with latest observations

We examine the validity of the $\Lambda$CDM model, and probe for the dynamics of dark energy using latest astronomical observations. Using the $Om(z)$ diagnosis, we find that different kinds of observational data are in tension within the $\Lambda$CDM framework. We then allow for dynamics of dark energy and investigate the constraint on dark energy parameters. We find that for two different kinds of parametrisations of the equation of state parameter $w$, a combination of current data mildly favours an evolving $w$, although the significance is not sufficient for it to be supported by the Bayesian evidence. A forecast of the DESI survey shows that the dynamics of dark energy could be detected at $7\sigma$ confidence level, and will be decisively supported by the Bayesian evidence, if the best fit model of $w$ derived from current data is the true model.Comment: 4.5 pages, 3 figures, 1 table; references adde