Constraints on dark matter-nucleon effective couplings in the presence of kinematically distinct halo substructures using the DEAP-3600 detector

DEAP-3600 is a single-phase liquid argon detector aiming to directly detect weakly interacting massive particles (WIMPs), located at SNOLAB (Sudbury, Canada). After analyzing data taken during the first year of operation, a null result was used to place an upper bound on the WIMP-nucleon, spin-independent, isoscalar cross section. This study reinterprets this result within a nonrelativistic effective field theory framework and further examines how various possible substructures in the local dark matter halo may affect these constraints. Such substructures are hinted at by kinematic structures in the local stellar distribution observed by the Gaia satellite and other recent astronomical surveys. These include the Gaia Sausage (or Enceladus), as well as a number of distinct streams identified in recent studies. Limits are presented for the coupling strength of the effective contact interaction operators O1, O3, O5, O8, and O11, considering isoscalar, isovector, and xenonphobic scenarios, as well as the specific operators corresponding to millicharge, magnetic dipole, electric dipole, and anapole interactions. The effects of halo substructures on each of these operators are explored as well, showing that the O5 and O8 operators are particularly sensitive to the velocity distribution, even at dark matter masses above 100 GeV=c

The S3 symmetric model with a dark scalar

We study the S3 symmetric extension of the Standard Model in which all the irreducible representations of the permutation group are occupied by SU(2) scalar doublets, one of which is taken as inert and can lead to dark matter candidates. We perform a scan over parameter space probing points against physical constraints ranging from unitarity tests to experimental Higgs searches limits. We find that the latter constraints severely restrict the parameter space of the model. For acceptable points we compute the value of the relic density of the dark scalar candidates and find that it has a region for low dark matter masses which complies with the Higgs searches bounds and lies within the experimental Planck limit. For masses ≳80 GeV the value of the relic density is below the Planck bound, and it reaches values close to it for very heavy masses ∼5 TeV. In this heavy mass region, this opens the interesting possibility of extending the dark sector of the model with additional particles. Keywords: Dark matter, Multi-Higgs model, S3 symmetric mode

An Inert Scalar In The S3 Symmetric Model

International audienceWe consider the S3 symmetric extension of the Standard Model in which all the irreducible representations of the permutation group are occupied by SU(2) scalar doublets, one of which is taken as inert. We study the parameter space of the model probing points against physical constraints ranging from unitarity tests to experimental Higgs searches limits. We find that the latter constraints severely restrict the parameter space of the model, and that the relic density of the dark matter candidates lies below the Planck bound for a large portion of the probed regions

The weak mixing angle from low energy neutrino measurements: A global update

Taking into account recent theoretical and experimental inputs on reactor fluxes we reconsider the determination of the weak mixing angle from low energy experiments. We perform a global analysis to all available neutrino–electron scattering data from reactor antineutrino experiments, obtaining sin2⁡θW=0.252±0.030. We discuss the impact of the new theoretical prediction for the neutrino spectrum, the new measurement of the reactor antineutrino spectrum by the Daya Bay collaboration, as well as the effect of radiative corrections. We also reanalyze the measurements of the νe−e cross section at accelerator experiments including radiative corrections. By combining reactor and accelerator data we obtain an improved determination for the weak mixing angle, sin2⁡θW=0.254±0.024

Effect of Extrusion Temperature on the Plastic Deformation of an Mg-Y-Zn Alloy Containing LPSO Phase Using In Situ Neutron Diffraction

The evolution of the internal strains during in situ tension and compression tests has been measured in an MgY$_2$Zn$_1$ alloy containing long-period stacking ordered (LPSO) phase using neutron diffraction. The alloy was extruded at two different temperatures to study the influence of the microstructure and texture of the magnesium and the LPSO phases on the deformation mechanisms. The alloy extruded at 623 K (350 °C) exhibits a strong fiber texture with the basal plane parallel to the extrusion direction due to the presence of areas of coarse non-recrystallised grains. However, at 723 K (450 °C), the magnesium phase is fully recrystallised with grains randomly oriented. On the other hand, at the two extrusion temperatures, the LPSO phase orients their basal plane parallel to the extrusion direction. Yield stress is always slightly higher in compression than in tension. Independently on the stress sign and the extrusion temperature, the beginning of plasticity is controlled by the activation of the basal slip system in the dynamic recrystallized grains. Therefore, the elongated fiber-shaped LPSO phase which behaves as the reinforcement in a metal matrix composite is responsible for this tension–compression asymmetry

Ecological vulnerability of the chondrichthyan fauna of southern Australia to the stressors of climate change, fishing and other anthropogenic hazards

We develop a potentially widely applicable framework for analysing the vulnerability, resilience risk and exposure of chondrichthyan species to all types of anthropogenic stressors in the marine environment. The approach combines the three components of widely applied vulnerability analysis (exposure, sensitivity and adaptability) (ESA) with three components (exposure, susceptibility and productivity) (ESP) of our adaptation of productivity–susceptibility analysis (PSA). We apply our 12-step ESA‒ESP analysis to evaluate the vulnerability (risk of a marked reduction of the population) of each of 132 chondrichthyan species in the Exclusive Economic Zone of southern Australia. The vul nerability relates to a species’ resilience to a spatial (or suitability) reduction of its habitats from exposure to up to eight climate change stressors. Vulnerability also relates to anthro pogenic mortality added to natural mortality from exposure to the stressors of five types of fishing and seven other types of anthropogenic hazards. We use biological attributes as risk factors to evaluate risk related to resilience at the species or higher taxonomic level. We evaluate each species’ exposure to anthropogenic stressors by assigning it to one of six ecological groups based on its lifestyle (demersal versus pelagic) and habitat, defined by bathymetric range and substrates. We evaluate vulnerability for 11 scenarios: 2000– 2006 when fishing effort peaked; 2018 following a decade of fisheries management reforms; low, medium and high standard future carbon dioxide equivalent emissions sce narios; and their six possible climate–fishing combinations. Our results demonstrate the value of refugia from fishing and how climate change exacerbates the risks from fishing.Fil: Walker, Terence I.. Monash University; Australia. The University of Melbourne; AustraliaFil: Day, Robert W.. The University of Melbourne; AustraliaFil: Awruch, Cynthia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Tasmania; AustraliaFil: Bell, Justin D.. Institute For Marine And Antarctic Studies; AustraliaFil: Braccini, Juan Matias. Wa Fisheries And Marine Research Laboratories; AustraliaFil: Dapp, Derek R.. Monash University; AustraliaFil: Finotto, Licia. Monash University; AustraliaFil: Frick, Lorenz H.. Monash University; AustraliaFil: Garcés-García, Karla C.. Universidad Veracruzana; México. The University of Melbourne; AustraliaFil: Guida, Leonardo. Monash University; AustraliaFil: Huveneers, Charlie. Flinders University; AustraliaFil: Martins, Camila L.. Monash University; AustraliaFil: Rochowski, Bastien E.A.. The University of Melbourne; AustraliaFil: Tovar-Ávila, Javier. Inapesca; MéxicoFil: Trinnie, Fabian I.. Wa Fisheries And Marine Research Laboratories; AustraliaFil: Reina, Richard D.. Monash University; Australi