Through the looking glass and what ATLAS found there: a Dark Sector search for light Dark Matter

Latest theories beyond the Standard Model predict a new `dark force' mediated by a light neutral particle called a dark photon, which opens a window to a complex Dark Sector. Through kinetic mixing a dark photon produced from the decay of a Higgs boson can decay back to SM particles with a sizeable lifetime, giving rise to striking signatures at hadron colliders. This work presents the results of a search for long-lived dark photons decaying into displaced collimated jet-like structures of leptons and light hadrons, referred to as `dark-photon jets'. The search uses data corresponding to an integrated luminosity of intlumi collected in proton--proton collisions at $sqrt{s} = 13$~TeV recorded in 2015--2016 of Run-2 data taking with the ATLAS detector at the Large Hadron Collider. The observed number of events is consistent with the expected background, and limits on the production cross section times branching fraction as a function of the proper decay length of the dark photon are reported. The enormous amount of data that will be collected by ATLAS during the Run-3 ($300~ifb$) and High-Luminosity ($3000~ifb$) 14 ev~LHC phase, and the updated ATLAS detector setup, will offer a unique opportunity to probe unexplored regions of phase space in the context of this search. Sensitivity prospects for Run-3 and High-Luminosity LHC are discussed and two new muon trigger algorithms are studied to improve the selection efficiency of displaced muon pairs. The current dark-photon jet analysis reach will continue to expand in parameter space and signature topologies proving to be a powerful tool for probing the Dark Sector at the LHC

First genome-wide data from Italian European beech (Fagus sylvatica L.): strong and ancient differentiation between Alps and Apennines

The European beech (Fagus sylvatica L.) is one of the most widespread forest trees in Europe whose distribution and intraspecific diversity has been largely shaped by repeated glacial cycles. Previous studies, mainly based on palaeobotanical evidence and a limited set of chloroplast and nuclear genetic markers, highlighted a complex phylogeographic scenario, with southern and western Europe characterized by a rather heterogeneous genetic structure, as a result of recolonization from different glacial refugia. Despite its ecological and economic importance, the genome of this broad-leaved tree has only recently been assembled, and its intra-species genomic diversity is still largely unexplored. Here, we performed whole-genome resequencing of nine Italian beech individuals sampled from two stands located in the Alpine and Apennine mountain ranges. We investigated patterns of genetic diversity at chloroplast, mitochondrial and nuclear genomes and we used chloroplast genomes to reconstruct a temporally-resolved phylogeny. Results allowed us to test European beech differentiation on a whole-genome level and to accurately date their divergence time. Our results showed comparable, relatively high levels of genomic diversity in the two populations and highlighted a clear differentiation at chloroplast, mitochondrial and nuclear genomes. The molecular clock analysis indicated an ancient split between the Alpine and Apennine populations, occurred between the Günz and the Riss glaciations (approximately 660 kyrs ago), suggesting a long history of separation for the two gene pools. This information has important conservation implications in the context of adaptation to ongoing climate change

COVID-19 in rheumatic diseases in Italy: first results from the Italian registry of the Italian Society for Rheumatology (CONTROL-19)

OBJECTIVES: Italy was one of the first countries significantly affected by the coronavirus disease 2019 (COVID-19) epidemic. The Italian Society for Rheumatology promptly launched a retrospective and anonymised data collection to monitor COVID-19 in patients with rheumatic and musculoskeletal diseases (RMDs), the CONTROL-19 surveillance database, which is part of the COVID-19 Global Rheumatology Alliance. METHODS: CONTROL-19 includes patients with RMDs and proven severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) updated until May 3rd 2020. In this analysis, only molecular diagnoses were included. The data collection covered demographic data, medical history (general and RMD-related), treatments and COVID-19 related features, treatments, and outcome. In this paper, we report the first descriptive data from the CONTROL-19 registry. RESULTS: The population of the first 232 patients (36% males) consisted mainly of elderly patients (mean age 62.2 years), who used corticosteroids (51.7%), and suffered from multi-morbidity (median comorbidities 2). Rheumatoid arthritis was the most frequent disease (34.1%), followed by spondyloarthritis (26.3%), connective tissue disease (21.1%) and vasculitis (11.2%). Most cases had an active disease (69.4%). Clinical presentation of COVID-19 was typical, with systemic symptoms (fever and asthenia) and respiratory symptoms. The overall outcome was severe, with high frequencies of hospitalisation (69.8%), respiratory support oxygen (55.7%), non-invasive ventilation (20.9%) or mechanical ventilation (7.5%), and 19% of deaths. Male patients typically manifested a worse prognosis. Immunomodulatory treatments were not significantly associated with an increased risk of intensive care unit admission/mechanical ventilation/death. CONCLUSIONS: Although the report mainly includes the most severe cases, its temporal and spatial trend supports the validity of the national surveillance system. More complete data are being acquired in order to both test the hypothesis that RMD patients may have a different outcome from that of the general population and determine the safety of immunomodulatory treatments

Report from Working Group 3: Beyond the standard model physics at the HL-LHC and HE-LHC

This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as $3$ ab$^{-1}$ of data taken at a centre-of-mass energy of 14 TeV, and of a possible future upgrade, the High Energy (HE) LHC, defined as $15$ ab$^{-1}$ of data at a centre-of-mass energy of 27 TeV. We consider a large variety of new physics models, both in a simplified model fashion and in a more model-dependent one. A long list of contributions from the theory and experimental (ATLAS, CMS, LHCb) communities have been collected and merged together to give a complete, wide, and consistent view of future prospects for BSM physics at the considered colliders. On top of the usual standard candles, such as supersymmetric simplified models and resonances, considered for the evaluation of future collider potentials, this report contains results on dark matter and dark sectors, long lived particles, leptoquarks, sterile neutrinos, axion-like particles, heavy scalars, vector-like quarks, and more. Particular attention is placed, especially in the study of the HL-LHC prospects, to the detector upgrades, the assessment of the future systematic uncertainties, and new experimental techniques. The general conclusion is that the HL-LHC, on top of allowing to extend the present LHC mass and coupling reach by $20-50\%$ on most new physics scenarios, will also be able to constrain, and potentially discover, new physics that is presently unconstrained. Moreover, compared to the HL-LHC, the reach in most observables will, generally more than double at the HE-LHC, which may represent a good candidate future facility for a final test of TeV-scale new physics

Through the looking glass and what ATLAS found there: a Dark Sector search for light Dark Matter

Latest theories beyond the Standard Model predict a new ‘dark force’ mediated by a light neutral particle called a dark photon, which opens a window to a complex Dark Sector. Through kinetic mixing a dark photon produced from the decay of a Higgs boson can decay back to SM particles with a sizeable lifetime, giving rise to striking signatures at hadron colliders. This work presents the results of a search for long-lived dark photons decaying into displaced collimated jet-like structures of leptons and light hadrons, referred to as ‘dark-photon jets’. The search uses data corresponding to an integrated luminosity of 36.1 fb$^{-1}$ collected in proton–proton collisions at $\sqrt{s}$ = 13 TeV recorded in 2015–2016 of Run-2 data taking with the ATLAS detector at the Large Hadron Collider. The observed number of events is consistent with the expected background, and limits on the production cross section times branching fraction as a function of the proper decay length of the dark photon are reported. The enormous amount of data that will be collected by ATLAS during the Run-3 (300fb$^{−1}$) and High-Luminosity (3000fb$^{−1}$) 14 TeVLHC phase, and the updated ATLAS detector setup, will offer a unique opportunity to probe unexplored regions of phase space in the context of this search. Sensitivity prospects for Run-3and High-Luminosity LHC are discussed and two new muon trigger algorithms are studied to improve the selection efficiency of displaced muon pairs. The current dark-photon jet analysis reach will continue to expand in parameter space and signature topologies proving to be a powerful tool for probing the Dark Sector at the LHC

Searches for exotic physics with unconventional signatures at ATLAS and CMS

Searches for exotic physics with unconventional signatures at ATLAS and CM

Exotic decays of the Higgs bosons

Precision studies of the properties of the Higgs bosons may provide a unique window for the discovery of new physics at the LHC. New phenomena can in particular be revealed in the search for lepton-flavor-violating or exotic decays of the Higgs bosons, as well as in their possible couplings to hidden-sector states that do not interact under Standard Model gauge transformations. This talk presents recent searches by the ATLAS experiment for decays of the Higgs bosons to new particles, using collision data at sqrt(s) = 13 TeV collected during the LHC Run 2

Long-Lived Particles at HL-LHC with the ATLAS detector.

Several new physics models that extend the Standard Model require the existence of Long-Lived Particle (LLP) as a solution for the problems like Dark Matter and Naturalness. The new ATLAS Phase-II setup with its huge statistics and updated detectors offers an opportunity to probe the yet unexplored region of the phase space. For muon spectrometer based searches neutral LLP decaying to collimated jets of leptons and light hadrons (lepton-jets) are of great interest. These particles offer an unique signature that can lead to an early discovery. New triggering techniques and algorithm have been developed and studied to improve the selection of highly boosted lepton-jets

Long-Lived Particles at HL-LHC with the ATLAS detector.

Several new physics models that extend the Standard Model require the existence of Long-Lived Particle (LLP) as a solution for the problems like Dark Matter and Naturalness. The ATLAS Phase-II upgrade detector and the expected large data set from high luminosity LHC upgrade offers an opportunity to probe the yet unexplored region of the phase space. For muon spectrometer based searches, neutral LLP decaying to collimated jets of leptons and light hadrons (lepton-jets) are of great interest. These particles offer an unique signature that can lead to an early discovery. New triggering techniques and algorithm have been developed and studied to improve the selection of highly boosted lepton-jets

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Several new physics models predict the existence of neutral particles with macroscopic life-times that decay to pairs of leptons and light hadrons with a jet-like structure (lepton-jets). These particles, decaying outside of the interaction region, will give rise to striking signatures in the detectors at the LHC. These can be detected through numerous unconventional signatures: long time-of-flight, late calorimetric energy deposits or displaced vertices. The most recent ATLAS results based on 36 fb−1 of data collected in proton-proton collisions at √s = 13 TeV recorded in 2015-2016 are presented. Prospects for the search for these particles with the ATLAS detector upgrade at HL-LHC are also given