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 Non-Relativistic 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 $\mathcal{O}_1$, $\mathcal{O}_3$, $\mathcal{O}_5$, $\mathcal{O}_8$, and $\mathcal{O}_{11}$, 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 $\mathcal{O}_5$ and $\mathcal{O}_8$ operators are particularly sensitive to the velocity distribution, even at dark matter masses above 100 GeV/$c^2$

The liquid-argon scintillation pulseshape in DEAP-3600

DEAP-3600 is a liquid-argon scintillation detector looking for dark matter. Scintillation events in the liquid argon (LAr) are registered by 255 photomultiplier tubes (PMTs), and pulseshape discrimination (PSD) is used to suppress electromagnetic background events. The excellent PSD performance of LAr makes it a viable target for dark matter searches, and the LAr scintillation pulseshape discussed here is the basis of PSD. The observed pulseshape is a combination of LAr scintillation physics with detector effects. We present a model for the pulseshape of electromagnetic background events in the energy region of interest for dark matter searches. The model is composed of (a) LAr scintillation physics, including the so-called intermediate component, (b) the time response of the TPB wavelength shifter, including delayed TPB emission at O(ms) time-scales, and c) PMT response. TPB is the wavelength shifter of choice in most LAr detectors. We find that approximately 10% of the intensity of the wavelength-shifted light is in a long-lived state of TPB. This causes light from an event to spill into subsequent events to an extent not usually accounted for in the design and data analysis of LAr-based detectors

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

Pulse-shape discrimination against low-energy Ar-39 beta decays in liquid argon with 4.5 tonne-years of DEAP-3600 data

The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from 39Ar beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator: the prompt-fraction, which considers the fraction of the scintillation signal in a narrow and a wide time window around the event peak, and the log-likelihood-ratio, which compares the observed photon arrival times to a signal and a background model. We furthermore use two algorithms to determine the number of photons detected at a given time: (1) simply dividing the charge of each PMT pulse by the mean single-photoelectron charge, and (2) a likelihood analysis that considers the probability to detect a certain number of photons at a given time, based on a model for the scintillation pulse shape and for afterpulsing in the light detectors. The prompt-fraction performs approximately as well as the log-likelihood-ratio PSD algorithm if the photon detection times are not biased by detector effects. We explain this result using a model for the information carried by scintillation photons as a function of the time when they are detected

Le mystère de la Sainte Tombe d'Arles-sur-Tech

Oliviéro . Le mystère de la Sainte Tombe d'Arles-sur-Tech. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, VII° Série. Tome 8 fascicule 4-6, 1927. pp. 217-220

Disponibilité des matériaux corporels et thérapies substitutives

Body materials availability and substitutives therapies We display the first results of a quasi-experimental research in health social psychology about the social interactions which are mediated by some body materials (blood, gamets, organs, tissus, genes, foetus neurons), used by substitutions therapies based on the principle of social communication of body materials. Three factors of human materials available to therapeutics are studied: the type of donor (oneself or close relative), the comparison process (oneself-close relative and close relative-oneself), and the objectivation/subjectivation process. This one seems to build up the topographical organisation which designs different biological materials catégories: somatic versus germinal, cadaver versus living human. The unvalaibility of body materials seems to be a function of the degree of subjectivation: the more they are subjectivated, the less they are available to the social communication. Paradoxically, transitional body materials (i.e. reproduction cells and cadaver) which are less related to subjectivity are the most unavailable. Différence between oneself/close relative seems also to be a function of subjectivation.Résumé. Nous présentons les premiers résultats d'une recherche quasi-expérimentale de psychologie sociale de la santé concernant certaines interactions sociales médiatisées par des matériaux corporels (sang, gamètes, organes, tissus, gènes, neurones fœtaux) utilisés dans le cadre des thérapies substitutives qui reposent sur le principe d'une communication sociale de matériaux corporels d'origine humaine. La disponibilité des matériaux humains en vue de leur usage thérapeutique est analysée en fonction du type de donneur (soi-même ou un proche), et des processus de comparaison (soi/proche et proche/soi) et de subjectivation. Ce dernier semble fonder l'organisation de la topographie que dessinent les différentes catégories de matériaux biologiques : matériaux somatiques versus germinaux ; matériaux prélevés versus morts. L'indisponibilité de ses propres matériaux comme de ceux d' autrui semble être une fonction du degré de subjectivation : plus les matériaux sont subjectives, moins ils s'avèrent disponibles pour leur communication sociale. Paradoxalement, ce sont les matériaux transitionnels (reproduction et cadavre), pour lesquels la présence d'une subjectivité est problématique, qui s'avèrent les plus indisponibles. Enfin, l'importance des écarts soi/proche semble une fonction du degré de subjectivation des matériaux.Disponibilidad de los materiales corporales y terapias substitutivas Presentamos los primeras resultados de una investigación cuasi experimental de psicología social de la salud que trata sobre ciertas interacciones sociales mediatizadas por materiales corporales (sangre, gametas, órganos, tejidos, gènes, neuronas fetales) utilizados en el marco de terapias substitutivas basadas en el principio de una comunicación social de estos materiales de origen humano. La disponibilidad de los materiales humanos para uso terapéutico está analizada en función del tipo de dona- dor (sí mismo o un prójimo), de los procesos de comparación (sí mismo/prójimo y prójimo/sí mismo) y de subjetivación. Esta última parece fundar la organización de la topografía que diseñan las diferentes categorías de materiales biológicos : materiales somáticos opuesto a germinales; materiales extraídos opuesto a muerto. La mdisponibilidad de los materiales propios como los de los otros parece ser una función del grado de subjetivación : cuanto más subjetivados están los materiales, menos disponibles están para su comunicación social. Paradojalmente, los materiales de transición (reproducción y cadáver), para los cuales la presencia de una subjetividad es problemática, son los más indisponibles. Enfin, la importancia de las distancias sí mismo/prójimo parece ser una función del grado de subjetivación de los materiales.Oliviéro Philippe. Disponibilité des matériaux corporels et thérapies substitutives. In: Sciences sociales et santé. Volume 15, n°2, 1997. pp. 35-67

Résistances et maquis en centre Bretagne : de la soumission à l'insurrection / Joseph Oliviéro, Yannick et Christian Perron

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