Measurements of electroweak W±Z boson pair production in association with two jets in pp collisions at √s = 13 TeV with the ATLAS detector

Measurements of integrated and differential cross-sections for electroweak W±Z production in association with two jets (W±Zjj) in proton-proton collisions are presented. The data collected by the ATLAS detector at the Large Hadron Collider from 2015 to 2018 at a centre-of-mass energy of √ s = 13 TeV are used, corresponding to an integrated luminosity of 140 fb−1 . The W±Zjj candidate events are reconstructed using leptonic decay modes of the gauge bosons. Events containing three identified leptons, either electrons or muons, and two jets are selected. Processes involving pure electroweak W±Zjj production at Born level are separated from W±Zjj production involving a strong coupling. The measured integrated fiducial cross-section of electroweak W±Zjj production per lepton flavour is σW Zjj−EW→ℓ ′ νℓℓjj = 0.368 ± 0.037 (stat.) ± 0.059 (syst.) ± 0.003 (lumi.) fb, where ℓ and ℓ ′ are either an electron or a muon. Respective cross-sections of electroweak and strong W±Zjj production are measured separately for events with exactly two jets or with more than two jets, and in three bins of the invariant mass of the two jets. The inclusive W±Zjj production cross-section, without separating electroweak and strong production, is also measured to be σW Zjj→ℓ ′ νℓℓjj = 1.462 ± 0.063 (stat.) ± 0.118 (syst.) ± 0.012 (lumi.) fb, per lepton flavour. The inclusive W±Zjj production cross-section is measured differentially for several kinematic observables. Finally, the measurements are used to constrain anomalous quartic gauge couplings by extracting 95% confidence level intervals on dimension-8 operators

Searches for exclusive Higgs boson decays into D⁎γ and Z boson decays into D0γ and Ks0γ in pp collisions at √s = 13 TeV with the ATLAS detector

Searches for exclusive decays of the Higgs boson into D⁎γ and of the Z boson into D0γ and Ks0γ can probe flavour-violating Higgs boson and Z boson couplings to light quarks. Searches for these decays are performed with a pp collision data sample corresponding to an integrated luminosity of 136.3 fb−1 collected at s=13TeV between 2016–2018 with the ATLAS detector at the CERN Large Hadron Collider. In the D⁎γ and D0γ channels, the observed (expected) 95% confidence-level upper limits on the respective branching fractions are B(H→D⁎γ)<1.0(1.2)×10−3, B(Z→D0γ)<4.0(3.4)×10−6, while the corresponding results in the Ks0γ channel are B(Z→Ks0γ)<3.1(3.0)×10−6

Measurement of vector boson production cross sections and their ratios using pp collisions at √s = 13.6 TeV with the ATLAS detector

Abstract available from publisher's website

Beam-induced backgrounds measured in the ATLAS detector during local gas injection into the LHC beam vacuum

Inelastic beam-gas collisions at the Large Hadron Collider (LHC), within a few hundred metres of the ATLAS experiment, are known to give the dominant contribution to beam backgrounds. These are monitored by ATLAS with a dedicated Beam Conditions Monitor (BCM) and with the rate of fake jets in the calorimeters. These two methods are complementary since the BCM probes backgrounds just around the beam pipe while fake jets are observed at radii of up to several metres. In order to quantify the correlation between the residual gas density in the LHC beam vacuum and the experimental backgrounds recorded by ATLAS, several dedicated tests were performed during LHC Run 2. Local pressure bumps, with a gas density several orders of magnitude higher than during normal operation, were introduced at different locations. The changes of beam-related backgrounds, seen in ATLAS, are correlated with the local pressure variation. In addition the rates of beam-gas events are estimated from the pressure measurements and pressure bump profiles obtained from calculations. Using these rates, the efficiency of the ATLAS beam background monitors to detect beam-gas events is derived as a function of distance from the interaction point. These efficiencies and characteristic distributions of fake jets from the beam backgrounds are found to be in good agreement with results of beam-gas simulations performed with theFluka Monte Carlo programme

La comunicazione precoce madre-bambino: un confronto fra diadi con bambino nato a termine e bambino nato pretermine

Il presente lavoro si pone l’obiettivo di osservare il coinvolgimento emotivo affettivo nelle interazioni diadiche madre-bambini. La ricerca è incentrata sull’influenza che la variabile nascita pretermine ha sullo sviluppo della relazione fra madre e bambino. A tale scopo si mettono a confronto diadi con bambini nati pretermine e diadi con bambini nati a termine, attraverso una ricerca osservativa longitudinale. Il campione dei bambini nati pretermine manifesta il culmine delle abilità sociali con un ritardo medio di 1-2 mesi rispetto ai bambini a termine. Anche le madri sembrano essere influenzate da tale andamento e manifestano, nel caso dei bambini pretermine, un maggior numero di comportamenti di interazione positivi ad un livello di età successivo rispetto alle madri dei nati a termine.The aim of this work is to observe the emotional involvement which characterizes the dyadic mother-infant interaction. The focus of the research is to assess the influence that the preterm birth variable has on the development of the mother-infant relationship. To this purpose dyads with preterm children and dyads with full-term children are compared through longitudinal observation. The preterm children reach the climax of their social competences with one/ two-month delay if compared with full term children. The mothers also seem to be influenced by this trend and a more positive range of maternal behaviours appear sensibly later than in the case of preterm infants

Load-independent inductive resonant WPT links

This paper presents the conditions and the design equations for obtaining a load-independent regime for an inductive resonant wireless power transfer link implemented through parallel resonators. The cases of a current and a voltage generator are analyzed and the possibility of obtaining a constant output voltage/current by operating at a suitable frequency is discussed. It is shown that in the case of a voltage generator it is not possible to choose the operating frequency so to obtain a constant output voltage, while it is possible to obtain a constant output current. Conversely, in the case of a current source, a load-independent output in terms of either voltage or current can be obtained by properly selecting the operating frequency

Asimmetrie espressivo-facciali in neonati a termine e pretermine durante lo stato di sonno attivo

Gli studi sulle asimmetrie facciali nell’infanzia hanno messo in evidenza come le espressioni di tipo emozionale nel corso dei primissimi anni di vita siano caratterizzate da una maggior intensità di contrazione del lato destro del volto (Best & Queen, 1989; Dondi, Brocadello, Tonzig, Simion, & Dalla Barba, 2002; Rothbart, Taylor, & Tucker, 1989). Da tali risultati si rileva un comportamento differente da quello osservato nell’adulto, che presenta, al contrario, un bias sul lato sinistro del volto (Borod, Haywood, & Koff, 1997). Questa differenza nelle asimmetrie espressivo-facciali è stata interpretata attraverso l’ipotesi “del gradiente di maturazione funzionale da destra verso sinistra” (Best, 1988; Best & Queen, 1989; Dondi et al., 2002; Rothbart et al., 1989), che presuppone un’influenza di tipo inibitorio dell’emisfero destro, più maturo rispetto al sinistro in questa fascia d’età, sulle vie sottocorticali dirette all’emifaccia sinistra (Best & Queen, 1989; Dondi et al., 2002; Rothbart et al., 1989). Al fine di verificare questa ipotesi, il presente studio ha preso in esame le asimmetrie facciali in espressioni a tono edonico positivo (sorrisi) e negativo (distress) in 10 neonati a termine e in 10 neonati pretermine durante lo stato di sonno attivo. In particolare è stata utilizzata la tecnica delle figure chimeriche, sottoponendo le immagini così ottenute alla valutazione di codificatori esperti. I risultati di questo studio hanno confermato la presenza significativa di un bias nell’emifaccia destra nei neonati a termine. Inaspettatamente, i neonati pretermine hanno mostrato una maggiore contrazione dell’emifaccia sinistra durante la manifestazione delle espressioni a tono edonico negativo

Asymmetries in newborn and premature infants' facial expression during active sleep state

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Different facial asymmetries in the exhibition of smiling in term and pre-term neonates at 40 weeks of post-conceptional age

To clarify the differences between term and pre-term neonates in expressing positive emotions during the first year of life, expert coders used FACS to describe lip corner raising (AU12) and lip corner raising with cheek raising (AU6 + AU12) produced by 22 healthy newborns, 11 born pre-term (8 females) and 11 born at term (8 females). Both groups were videotaped when infants reached the 40th week of post-conceptional age. No differences were found regarding rate per minute and mean duration of Duchenne and non-Duchenne smiling. Nonetheless, significant differences in facial asymmetries between the groups emerged from the analyses. In particular, pre-term infants showed a relatively frequent leftward bias, that is a tendency to contract more rapidly and with more intensity the left hemiface rather than the right hemiface. Left biased bilateral and unilateral facial actions were very rarely observed in the full-term group where an opposite trend was recorded (rightward bias)