Development of a Standardized DNA Database for Chinook Salmon

An international multi-laboratory project was conducted to develop a standardized DNA database for Chinook salmon (Oncorhynchus tshawytscha). This project was in response to the needs of the Chinook Technical Committee of the Pacific Salmon Commission to identify stock composition of Chinook salmon caught in fisheries during their oceanic migrations. Nine genetics laboratories identified 13 microsatellite loci that could be reproducibly assayed in each of the laboratories. To test that the loci were reproducible among laboratories, blind tests were conducted to verify scoring consistency for the nearly 500 total alleles. Once standardized, a dataset of over 16,000 Chinook salmon representing 110 putative populations was constructed ranging throughout the area of interest of the Pacific Salmon Commission from Southeast Alaska to the Sacramento River in California. The dataset differentiates the major known genetic lineages of Chinook salmon and provides a tool for genetic stock identification of samples collected from mixed fisheries. A diverse group of scientists representing the disciplines of fishery management, genetics, fishery administration, population dynamics, and sampling theory are now developing recommendations for the integration of these genetic data into ocean salmon management.Original Abstract: Se realizo un proyecto internacional con la participation de diversos laboratorios con la finalidad de desarrollar una base de datos estandarizada de DNA para el salmon rey (Oncorhynchus tshawytscha). Dicho proyecto surgi6 como respuesta a las necesidades del Comite Tecnico Chinook de la Comision del Salmon del Pacifico para identificar la composition poblacional del salmon rey que es capturado por la pesqueria durante su migration. Un total de nueve laboratorios de analisis geneticos identificaron y reprodujeron cada uno 13 loci microsatelites. Con el objeto de probar que dichos loci fueran reproducibles entre laboratorios, se condujeron pruebas anonimas para verificar la consistencia de casi 500 alelos. Una vez estandarizada, se construyo una base de datos construida con information proveniente de mas de 16,000 salmones que representan 110 poblaciones putativas distribuidas a lo largo del area de interes de la Comision del Salm6n del Pacifico, del sureste de Alaska hasta el Rio Sacramento, California. La base de datos sirve tanto para identificar gene'ticamente los distintos stocks de salmon rey a partir de muestras combinadas provenientes de la pesqueria como para diferenciar el linaje genetico conocido mas importante de esta especie. En la actualidad, un importante grupo de cientificos especializados en disciplinas como el manejo y administracion de pesquerias, genetica, dinamica poblacional y teoria del muestreo estan desarrollando recomendaciones para que esta base de datos geneticos se incorpore en el manejo del salmon

Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector

The observation of Higgs boson production in association with a top quark pair (tt H¯ ), based on the analysis of proton–proton collision data at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider, is presented. Using data corresponding to integrated luminosities of up to 79.8 fb−1, and considering Higgs boson decays into b¯ b, W W ∗, τ +τ −, γγ , and Z Z∗, the observed significance is 5.8 standard deviations, compared to an expectation of 4.9 standard deviations. Combined with the tt H¯ searches using a dataset corresponding to integrated luminosities of 4.5 fb−1 at 7 TeV and 20.3 fb−1 at 8 TeV, the observed (expected) significance is 6.3 (5.1) standard deviations. Assuming Standard Model branching fractions, the total tt H¯ production cross section at 13 TeV is measured to be 670 ± 90 (stat.) +110 −100 (syst.) fb, in agreement with the Standard Model prediction

Muon Collider Forum Report

A multi-TeV muon collider offers a spectacular opportunity in the direct exploration of the energy frontier. Offering a combination of unprecedented energy collisions in a comparatively clean leptonic environment, a high energy muon collider has the unique potential to provide both precision measurements and the highest energy reach in one machine that cannot be paralleled by any currently available technology. The topic generated a lot of excitement in Snowmass meetings and continues to attract a large number of supporters, including many from the early career community. In light of this very strong interest within the US particle physics community, Snowmass Energy, Theory and Accelerator Frontiers created a cross-frontier Muon Collider Forum in November of 2020. The Forum has been meeting on a monthly basis and organized several topical workshops dedicated to physics, accelerator technology, and detector R&D. Findings of the Forum are summarized in this report

Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider

International audienceParticles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton–proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments—as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER—to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity ‘dark showers’, highlighting opportunities for expanding the LHC reach for these signals