The design, implementation, and performance of the LZ calibration systems

LUX-ZEPLIN (LZ) is a tonne-scale experiment searching for direct dark matter interactions and other rare events. It is located at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. The core of the LZ detector is a dual-phase xenon time projection chamber (TPC), designed with the primary goal of detecting Weakly Interacting Massive Particles (WIMPs) via their induced low energy nuclear recoils. Surrounding the TPC, two veto detectors immersed in an ultra-pure water tank enable reducing background events to enhance the discovery potential. Intricate calibration systems are purposely designed to precisely understand the responses of these three detector volumes to various types of particle interactions and to demonstrate LZ's ability to discriminate between signals and backgrounds. In this paper, we present a comprehensive discussion of the key features, requirements, and performance of the LZ calibration systems, which play a crucial role in enabling LZ's WIMP-search and its broad science program. The thorough description of these calibration systems, with an emphasis on their novel aspects, is valuable for future calibration efforts in direct dark matter and other rare-event search experiments

New constraints on ultraheavy dark matter from the LZ experiment

Searches for dark matter with liquid xenon time projection chamber experiments have traditionally focused on the region of the parameter space that is characteristic of weakly interacting massive particles, ranging from a few GeV/c2 to a few TeV/c2. Models of dark matter with a mass much heavier than this are well motivated by early production mechanisms different from the standard thermal freeze-out, but they have generally been less explored experimentally. In this work, we present a reanalysis of the first science run of the LZ experiment, with an exposure of 0.9  tonne×yr, to search for ultraheavy particle dark matter. The signal topology consists of multiple energy deposits in the active region of the detector forming a straight line, from which the velocity of the incoming particle can be reconstructed on an event-by-event basis. Zero events with this topology were observed after applying the data selection calibrated on a simulated sample of signal-like events. New experimental constraints are derived, which rule out previously unexplored regions of the dark matter parameter space of spin-independent interactions beyond a mass of 1017  GeV/c2. Published by the American Physical Society 2024 </jats:sec

Caffeine ingestion effects on oxidative stress in a steady-state test at 75% VO2 max

In cases of insolvency, the security-holder is preferred to other creditors with respect to the outcome of sale of the object of the security. The article considers whether the preferential treatment of secured claims is justified. The situation is more complex in the case of the floating charge, because the object of the floating charge differs from that of other charges. The author maintains that the floating charge is an easy, convenient, and flexible way to secure a claim while both protecting the creditor’s interests and allowing the debtor to sell his property where necessary. On the other side, the floating charge covers almost all movable property of the debtor, which is sold in full to cover the claim. In such cases, unsecured creditors end up with nothing. Such a situation may amount to unequal treatment of unsecured creditors. For this reason, the author concludes that, relative to regular secured creditors, less preferential treatment of floating-charge holders may be justified. The author suggests creating a system for distributing a fair amount of money to the unsecured creditors on the account of the floating-charge holder’s fund

Professional and Personal Experience through Lifelong Learning and Regular Sport (PROPELLERS)—A Study Protocol

Physical inactivity (PI) and sedentary behaviours constitute a global health problem that has negative consequences for health and is also considered the fourth leading risk factor for global mortality. A European project named ‘Professional and Personal Experience through Lifelong Learning and Regular Sport’ aims to encourage voluntary participation in sporting activities to achieve its benefits on health. First, a report will be carried out on the effects of physical activity (PA) or inactivity on health, which is often linked to school failure, obesity, self-esteem, etc. The data will be obtained through a completely anonymous online sport and health questionnaire, addressed to all profiles. The data collected through this survey will serve as a basis for understanding the reality of Europeans in terms of quality of life, demographics, physical fitness, and other factors. It is also intended to design a handbook with recommendations for improving health holistically through PA. Finally, the goal is to translate this project into a teaching system for sports professionals, so that they can transfer this knowledge as educational methods to improve people’s health, while adapting it to the particularities of each country, i.e., to provide these sports professionals with tools to train other people. © 2022 by the authors