Aportación al conocimiento paleoecológico del Holoceno en el NW de la Península Ibérica

Se ha hecho análisis polínico de dos palcosudos enterrados bajo un yacimiento arqueológico de cultura catrexa y dt un depósito lacustre. Los tres está.n geográficamente próximos y son com:lacionablc.~ debido a la CXJSI-encia d!:.datacioncs C-14 y a datos culturales. Coll los datos polfnicos obtenidos, se ban hecho dos diagramas en los que se dcfmcn distintas etapas de vegetación dc5dc finales del Sub-Boreal al Sub-Atlántico actual. Dichas etapas son: fin Uel Sub-Boreal con boS()UC de Q¡:e~eu.r y presencia de ÚlJianea; expansión del roble a comien- 7.0s del Sub-Atlántico y presencia deAinus; fase de cultivo de COJtanta hacia 1580 B.P .; fase de máxima dcforcsucióo y fmalmcntc, fase. de cultivo dcPjnr.uA polleo analysi! of two palcosoih buricd under an arcbacological deposit o[ caHcxa culture aod Jakc dcposils was carricd out. Thc thrcc are geograpbkally close and are relatcd as tbe cOOstence of C-14 data and cultaral in(onnation preves. With the po11en data oblai.ned we dcvi.sed rwo diagrams dcfming severa! Mage..~ of vegc.tation ranging from thc cnd of lhc Sub-Boreal te thc prcscnt Sub·Atlantic. Thcse stagcs are: tbc cnd of tbc Sub-Boreal wi tb QuerroJ furcsts and thc prcsc:mx: of Ca¡ftm , u; extcrmon o( oaks at thc bcginning of thc Sub-Atlantic and the presence of Afnus; tbe Castnnea cultivation phase (rom about 1580 B.P .; the maximum deforcslation phase and lastly, cultivation ofthe Pil11tS phas

Aportación al estudio palinológico del género quercus en Galicia

Se realiza el estudio biométrico del polen de Quercus r obur L., Q_ petraea Liebl., Q. pyrenaica Will., Q. i l ex L. y Q. s uber L., de muestras recogidas en disti nta·s localidades gal l egas , obteniendose la dimensión y relación dimensional más significativa para su diferenciación . Se aplican estos resul tactos al análi,sis pol inice de la laguna colmatada de La Lucenza (Lugo}, donde existe un espectro continuo de Quercus , e n l a que se observa un aumento progresivo del tamaño de grano de polen con la profundidad.on réalise une étude biométrique du pollen de Quercus robur L. , Q. petraea Liebl., Q. pyr enaica Will., Q. i l ex L., Q_ s uber L. La taille et l e rapport des dimens i ons le plus significatif pour leur diffé r entiation sont presenté es . Les résul tats sont apliquées a 1' anal yse pollinique d 'une lacune encombrée (La Lucenza, Lugo) , ou on peut apprecér un spectre conti nu du genre Quercus , ayant l ieu une augmentation progre si ve de la taille des gra ins de pol l en avec la prof undeur

Search for the Zγ decay mode of new high-mass resonances in pp collisions at √s = 13 TeV with the ATLAS detector

This letter presents a search for narrow, high-mass resonances in the Zγ final state with the Z boson decaying into a pair of electrons or muons. The √s = 13 TeV pp collision data were recorded by the ATLAS detector at the CERN Large Hadron Collider and have an integrated luminosity of 140 fb−1. The data are found to be in agreement with the Standard Model background expectation. Upper limits are set on the resonance production cross section times the decay branching ratio into Zγ. For spin-0 resonances produced via gluon–gluon fusion, the observed limits at 95% confidence level vary between 65.5 fb and 0.6 fb, while for spin-2 resonances produced via gluon–gluon fusion (or quark–antiquark initial states) limits vary between 77.4 (76.1) fb and 0.6 (0.5) fb, for the mass range from 220 GeV to 3400 GeV

Search for heavy resonances decaying into a Z or W boson and a Higgs boson in final states with leptons and b-jets in 139 fb−1 of pp collisions at s√ = 13 TeV with the ATLAS detector

This article presents a search for new resonances decaying into a Z or W boson and a 125 GeV Higgs boson h, and it targets the νν¯¯¯bb¯¯, ℓ+ℓ−bb¯¯, or ℓ±νbb¯¯ final states, where ℓ = e or μ, in proton-proton collisions at s√ = 13 TeV. The data used correspond to a total integrated luminosity of 139 fb−1 collected by the ATLAS detector during Run 2 of the LHC at CERN. The search is conducted by examining the reconstructed invariant or transverse mass distributions of Zh or Wh candidates for evidence of a localised excess in the mass range from 220 GeV to 5 TeV. No significant excess is observed and 95% confidence-level upper limits between 1.3 pb and 0.3 fb are placed on the production cross section times branching fraction of neutral and charged spin-1 resonances and CP-odd scalar bosons. These limits are converted into constraints on the parameter space of the Heavy Vector Triplet model and the two-Higgs-doublet model

The ATLAS trigger system for LHC Run 3 and trigger performance in 2022

The ATLAS trigger system is a crucial component of the ATLAS experiment at the LHC. It is responsible for selecting events in line with the ATLAS physics programme. This paper presents an overview of the changes to the trigger and data acquisition system during the second long shutdown of the LHC, and shows the performance of the trigger system and its components in the proton-proton collisions during the 2022 commissioning period as well as its expected performance in proton-proton and heavy-ion collisions for the remainder of the third LHC data-taking period (2022–2025)

Search for third-generation vector-like leptons in pp collisions at s√ = 13 TeV with the ATLAS detector

A search for vector-like leptons in multilepton (two, three, or four-or-more electrons plus muons) final states with zero or more hadronic τ-lepton decays is presented. The search is performed using a dataset corresponding to an integrated luminosity of 139 fb−1 of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the LHC. To maximize the separation of signal and background, a machine-learning classifier is used. No excess of events is observed beyond the Standard Model expectation. Using a doublet vector-like lepton model, vector-like leptons coupling to third-generation Standard Model leptons are excluded in the mass range from 130 GeV to 900 GeV at the 95% confidence level, while the highest excluded mass is expected to be 970 GeV

Search for a new heavy scalar particle decaying into a Higgs boson and a new scalar singlet in final states with one or two light leptons and a pair of τ-leptons with the ATLAS detector

A search for a new heavy scalar particle X decaying into a Standard Model (SM) Higgs boson and a new singlet scalar particle S is presented. The search uses a proton-proton (pp) collision data sample with an integrated luminosity of 140 fb−1 recorded at a centre-of-mass energy of s√ = 13 TeV with the ATLAS detector at the Large Hadron Collider. The most sensitive mass parameter space is explored in X mass ranging from 500 to 1500 GeV, with the corresponding S mass in the range 200–500 GeV. The search selects events with two hadronically decaying τ-lepton candidates from H → τ+τ− decays and one or two light leptons (ℓ = e, μ) from S → VV (V = W, Z) decays while the remaining V boson decays hadronically or to neutrinos. A multivariate discriminant based on event kinematics is used to separate the signal from the background. No excess is observed beyond the expected SM background and 95% confidence level upper limits between 72 fb and 542 fb are derived on the cross-section σ(pp → X → SH) assuming the same SM-Higgs boson-like decay branching ratios for the S → VV decay. Upper limits on the visible cross-sections σ(pp → X → SH → WWττ) and σ(pp → X → SH → ZZττ) are also set in the ranges 3–26 fb and 6–33 fb, respectively

Evidence for the charge asymmetry in pp → tt¯ production at s√ = 13 TeV with the ATLAS detector

Inclusive and differential measurements of the top–antitop (tt¯) charge asymmetry Att¯C and the leptonic asymmetry Aℓℓ¯C are presented in proton–proton collisions at s√ = 13 TeV recorded by the ATLAS experiment at the CERN Large Hadron Collider. The measurement uses the complete Run 2 dataset, corresponding to an integrated luminosity of 139 fb−1, combines data in the single-lepton and dilepton channels, and employs reconstruction techniques adapted to both the resolved and boosted topologies. A Bayesian unfolding procedure is performed to correct for detector resolution and acceptance effects. The combined inclusive tt¯ charge asymmetry is measured to be Att¯C = 0.0068 ± 0.0015, which differs from zero by 4.7 standard deviations. Differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the tt¯ system. Both the inclusive and differential measurements are found to be compatible with the Standard Model predictions, at next-to-next-to-leading order in quantum chromodynamics perturbation theory with next-to-leading-order electroweak corrections. The measurements are interpreted in the framework of the Standard Model effective field theory, placing competitive bounds on several Wilson coefficients

Measurement of the cross-sections of the electroweak and total production of a Zγ pair in association with two jets in pp collisions at √s = 13 TeV with the ATLAS detector

This Letter presents the measurement of the fiducial and differential cross-sections of the electroweak production of a Zγ pair in association with two jets. The analysis uses 140 fb−1 of LHC proton–proton collision data taken at √s = 13 TeV recorded by the ATLAS detector during the years 2015–2018. Events with a Z boson candidate decaying into either an e+e− or μ+μ− pair, a photon and two jets are selected. The electroweak component is extracted by requiring a large dijet invariant mass and by using the information about the centrality of the system and is measured with an observed and expected significance well above five standard deviations. The fiducial pp → Zγ jj cross-section for the electroweak production is measured to be 3.6 ± 0.5 fb. The total fiducial cross-section that also includes contributions where the jets arise from strong interactions is measured to be 16.8+2.0 −1.8 fb. The results are consistent with the Standard Model predictions. Differential cross-sections are also measured using the same events and are compared with parton-shower Monte Carlo simulations. Good agreement is observed between data and predictions