Showing papers by "IFAE published in 2019"
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TL;DR: An exclusion limit on the H→invisible branching ratio of 0.26(0.17_{-0.05}^{+0.07}) at 95% confidence level is observed (expected) in combination with the results at sqrt[s]=7 and 8 TeV.
Abstract: Dark matter particles, if sufficiently light, may be produced in decays of the Higgs boson. This Letter presents a statistical combination of searches for H→invisible decays where H is produced according to the standard model via vector boson fusion, Z(ll)H, and W/Z(had)H, all performed with the ATLAS detector using 36.1 fb^{-1} of pp collisions at a center-of-mass energy of sqrt[s]=13 TeV at the LHC. In combination with the results at sqrt[s]=7 and 8 TeV, an exclusion limit on the H→invisible branching ratio of 0.26(0.17_{-0.05}^{+0.07}) at 95% confidence level is observed (expected).
234 citations
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TL;DR: In this article, an improved energy clustering algorithm is introduced, and its implications for the measurement and identification of prompt electrons and photons are discussed in detail, including corrections and calibrations that affect performance, including energy calibration, identification and isolation efficiencies.
Abstract: This paper describes the reconstruction of electrons and photons with the ATLAS detector, employed for measurements and searches exploiting the complete LHC Run 2 dataset. An improved energy clustering algorithm is introduced, and its implications for the measurement and identification of prompt electrons and photons are discussed in detail. Corrections and calibrations that affect performance, including energy calibration, identification and isolation efficiencies, and the measurement of the charge of reconstructed electron candidates are determined using up to 81 fb−1 of proton-proton collision data collected at √s=13 TeV between 2015 and 2017.
227 citations
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TL;DR: In this article, the ATLAS Collaboration during Run 2 of the Large Hadron Collider (LHC) was used to identify jets containing b-hadrons, and the performance of the algorithms was evaluated in the s...
Abstract: The algorithms used by the ATLAS Collaboration during Run 2 of the Large Hadron Collider to identify jets containing b-hadrons are presented. The performance of the algorithms is evaluated in the s ...
210 citations
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TL;DR: In this paper, the decays of B0 s! + and B0! + have been studied using 26 : 3 fb of 13TeV LHC proton-proton collision data collected with the ATLAS detector in 2015 and 2016.
Abstract: A study of the decays B0 s ! + and B0 ! + has been performed using 26 : 3 fb of 13TeV LHC proton-proton collision data collected with the ATLAS detector in 2015 and 2016. Since the detector resolut ...
180 citations
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TL;DR: Capdevila et al. as discussed by the authors performed a model-independent global fit to confirm existing New Physics (NP) patterns and identify new ones emerging from the inclusion of the updated LHCb and Belle measurements of $$R_K$$ and $$R_{K^*}$$, respectively.
Abstract: We perform a model-independent global fit to $$b\rightarrow s\ell ^+\ell ^-$$ observables to confirm existing New Physics (NP) patterns (or scenarios) and to identify new ones emerging from the inclusion of the updated LHCb and Belle measurements of $$R_K$$ and $$R_{K^*}$$, respectively. Our analysis, updating Refs. Capdevila et al. (J Virto JHEP 1801:093, 2018) and Alguero et al. (J Matias Phys Rev D 99(7):075017, 2019) and including these new data, suggests the presence of right-handed couplings encoded in the Wilson coefficients $${{{\mathcal {C}}}}_{9'\mu }$$ and $${{{\mathcal {C}}}}_{10'\mu }$$. It also strengthens our earlier observation that a lepton flavour universality violating (LFUV) left-handed lepton coupling ($${{{\mathcal {C}}}}_{9\mu }^{\mathrm{V}}=-\,{{{\mathcal {C}}}}_{10\mu }^{\mathrm{V}}$$), often preferred from the model building point of view, accommodates the data better if lepton-flavour universal (LFU) NP is allowed, in particular in $${{{\mathcal {C}}}}_{9}^{\mathrm{U}}$$. Furthermore, this scenario with LFU NP provides a simple and model-independent connection to the $$b\rightarrow c\tau
u $$ anomalies, showing a preference of $$\approx 7\,\sigma $$ with respect to the SM. It may also explain why fits to the whole set of $$b\rightarrow s\ell ^+\ell ^-$$ data or to the subset of LFUV data exhibit stronger preferences for different NP scenarios. Finally, motivated by $$Z^\prime $$ models with vector-like quarks, we propose four new scenarios with LFU and LFUV NP contributions that give a very good fit to data.
168 citations
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TL;DR: In this paper, the first cosmological parameter constraints using measurements of type Ia supernovae (SNe Ia) from the Dark Energy Survey Supernova Program (DES-SN) were presented.
Abstract: We present the first cosmological parameter constraints using measurements of type Ia supernovae (SNe Ia) from the Dark Energy Survey Supernova Program (DES-SN). The analysis uses a subsample of 207 spectroscopically confirmed SNe Ia from the first three years of DES-SN, combined with a low-redshift sample of 122 SNe from the literature. Our "DES-SN3YR" result from these 329 SNe Ia is based on a series of companion analyses and improvements covering SN Ia discovery, spectroscopic selection, photometry, calibration, distance bias corrections, and evaluation of systematic uncertainties. For a flat ΛCDM model we find a matter density ${{\rm{\Omega }}}_{{\rm{m}}}=0.331\pm 0.038$. For a flat wCDM model, and combining our SN Ia constraints with those from the cosmic microwave background (CMB), we find a dark energy equation of state $w=-0.978\pm 0.059$, and ${{\rm{\Omega }}}_{{\rm{m}}}=0.321\pm 0.018$. For a flat w 0 w a CDM model, and combining probes from SN Ia, CMB and baryon acoustic oscillations, we find ${w}_{0}=-0.885\pm 0.114$ and ${w}_{a}=-0.387\,\pm \,0.430$. These results are in agreement with a cosmological constant and with previous constraints using SNe Ia (Pantheon, JLA).
157 citations
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University College London1, Rhodes University2, Fermilab3, Sao Paulo State University4, Autonomous University of Madrid5, University of Portsmouth6, University of Cambridge7, Carnegie Institution for Science8, University of Pennsylvania9, Institut d'Astrophysique de Paris10, Stanford University11, University of São Paulo12, University of Illinois at Urbana–Champaign13, IFAE14, Sun Yat-sen University15, Texas A&M University16, Indian Institute of Technology, Hyderabad17, University of Arizona18, California Institute of Technology19, University of Manchester20, University of Michigan21, Ludwig Maximilian University of Munich22, ETH Zurich23, University of California, Santa Cruz24, Ohio State University25, Max Planck Society26, Harvard University27, Australian Astronomical Observatory28, Argonne National Laboratory29, University of Geneva30, University of Sussex31, Universidade Federal do Rio Grande do Sul32, Brookhaven National Laboratory33, University of Southampton34, State University of Campinas35, Oak Ridge National Laboratory36
TL;DR: In this paper, the authors presented the results of a study at the Ohio State University's Center for Cosmology and Astro-Particle Physics (CSOP) at the University of Illinois at Urbana-Champaign.
Abstract: Ohio State University Center for Cosmology and AstroParticle Physics; Spanish Ramon y Cajal MICINN program; Spanish Ministerio de Economia y Competitividad [ESP2013-48274-C3-1-P]; Juan de la Cierva fellowship; Brazilian Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Sao Paulo Research Foundation (FAPESP); CNPq; Instituto Nacional de Ciencia e Tecnologia (INCT) e-Universe (CNPq) [465376/2014-2]; 'Plan Estatal de Investigacion Cientfica y Tecnica y de Innovacion' program of the Spanish government; U.S. Department of Energy; U.S. National Science Foundation; Ministry of Science and Education of Spain; Science and Technology Facilities Council of the United Kingdom; Higher Education Funding Council for England; National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign; Kavli Institute of Cosmological Physics at the University of Chicago; Center for Cosmology and Astro-Particle Physics at the Ohio State University; Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University; Financiadora de Estudos e Projetos; Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico; Ministerio da Ciencia, Tecnologia e Inovacao; Deutsche Forschungsgemeinschaft; Argonne National Laboratory; University of California at Santa Cruz; University of Cambridge; Centro de Investigaciones Energeticas; Medioambientales y Tecnologicas-Madrid; University of Chicago; University College London; DES-Brazil Consortium; University of Edinburgh; Eidgenossische Technische Hochschule (ETH) Zurich; Fermi National Accelerator Laboratory; University of Illinois at Urbana-Champaign; Institut de Ciencies de l'Espai (IEEC/CSIC); Institut de Fisica d'Altes Energies; Lawrence Berkeley National Laboratory; Ludwig-Maximilians Universitat Munchen; associated Excellence Cluster Universe; University of Michigan; National Optical Astronomy Observatory; University of Nottingham; Ohio State University; University of Pennsylvania; University of Portsmouth; SLAC National Accelerator Laboratory; Stanford University; University of Sussex; Texas AM University; OzDES Membership Consortium; National Science Foundation [AST-1138766, AST-1536171]; MINECO [AYA2015-71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV-2016-0597, MDM-2015-0509]; ERDF funds from the European Union; CERCA program of the Generalitat de Catalunya; European Research Council under the European Union; ERC [240672, 291329, 306478]; Australian Research Council Centre of Excellence [CE110001020]; U.S. Department of Energy, Office of Science, Office of High Energy Physics [DE-AC02-07CH11359]
156 citations
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University of Arizona1, Max Planck Society2, Ludwig Maximilian University of Munich3, Stanford University4, SLAC National Accelerator Laboratory5, University of Pennsylvania6, Princeton University7, Brookhaven National Laboratory8, Fermilab9, Stony Brook University10, Santa Cruz Institute for Particle Physics11, University of Sussex12, University of Michigan13, ETH Zurich14, University College London15, Carnegie Mellon University16, Ohio State University17, California Institute of Technology18, University of California, Riverside19, Brandeis University20, University of Edinburgh21, Rhodes University22, Institute of Cosmology and Gravitation, University of Portsmouth23, University of Manchester24, University of Illinois at Urbana–Champaign25, National Center for Supercomputing Applications26, IFAE27, Spanish National Research Council28, University of Chicago29, Autonomous University of Madrid30, University of Cambridge31, Harvard University32, Steward Health Care System33, Australian Astronomical Observatory34, University of São Paulo35, Texas A&M University36, Catalan Institution for Research and Advanced Studies37, University of Southampton38, State University of Campinas39, Oak Ridge National Laboratory40, Argonne National Laboratory41
TL;DR: In this paper, the authors constrain the normalization of the scaling relation at the 5.0 per cent level as M 0 =[3.081±0.075(stat)± 0.133(sys)]⋅10 14 M ⊙ at λ=40 and z=0.35.
Abstract: We constrain the mass--richness scaling relation of redMaPPer galaxy clusters identified in the Dark Energy Survey Year 1 data using weak gravitational lensing. We split clusters into 4×3 bins of richness λ and redshift z for λ≥20 and 0.2≤z≤0.65 and measure the mean masses of these bins using their stacked weak lensing signal. By modeling the scaling relation as ⟨M 200m |λ,z⟩=M 0 (λ/40) F ((1+z)/1.35) G , we constrain the normalization of the scaling relation at the 5.0 per cent level as M 0 =[3.081±0.075(stat)±0.133(sys)]⋅10 14 M ⊙ at λ=40 and z=0.35 . The richness scaling index is constrained to be F=1.356±0.051 (stat)±0.008 (sys) and the redshift scaling index G=−0.30±0.30 (stat)±0.06 (sys) . These are the tightest measurements of the normalization and richness scaling index made to date. We use a semi-analytic covariance matrix to characterize the statistical errors in the recovered weak lensing profiles. Our analysis accounts for the following sources of systematic error: shear and photometric redshift errors, cluster miscentering, cluster member dilution of the source sample, systematic uncertainties in the modeling of the halo--mass correlation function, halo triaxiality, and projection effects. We discuss prospects for reducing this systematic error budget, which dominates the uncertainty on M 0. Our result is in excellent agreement with, but has significantly smaller uncertainties than, previous measurements in the literature, and augurs well for the power of the DES cluster survey as a tool for precision cosmology and upcoming galaxy surveys such as LSST, Euclid and WFIRST.
154 citations
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TL;DR: Algorithms used for the reconstruction and identification of electrons in the central region of the ATLAS detector at the Large Hadron Collider (LHC) are presented in this article, these algorithms a...
Abstract: Algorithms used for the reconstruction and identification of electrons in the central region of the ATLAS detector at the Large Hadron Collider (LHC) are presented in this paper; these algorithms a ...
140 citations
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TL;DR: Combined results from these probes derive constraints on the equation of state, w, of dark energy and its energy density in the Universe, demonstrating the potential power of large multiprobe photometric surveys and paving the way for order of magnitude advances in constraints on properties ofdark energy and cosmology over the next decade.
Abstract: The combination of multiple observational probes has long been advocated as a powerful technique to constrain cosmological parameters, in particular dark energy. The Dark Energy Survey has measured 207 spectroscopically confirmed type Ia supernova light curves, the baryon acoustic oscillation feature, weak gravitational lensing, and galaxy clustering. Here we present combined results from these probes, deriving constraints on the equation of state, w, of dark energy and its energy density in the Universe. Independently of other experiments, such as those that measure the cosmic microwave background, the probes from this single photometric survey rule out a Universe with no dark energy, finding w=-0.80_{-0.11}^{+0.09}. The geometry is shown to be consistent with a spatially flat Universe, and we obtain a constraint on the baryon density of Ω_{b}=0.069_{-0.012}^{+0.009} that is independent of early Universe measurements. These results demonstrate the potential power of large multiprobe photometric surveys and pave the way for order of magnitude advances in our constraints on properties of dark energy and cosmology over the next decade.
107 citations
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TL;DR: This Letter describes the observation of the light-by-light scattering process, γγ→γγ, in Pb+Pb collisions at sqrt[s_{NN}]=5.02 TeV, and the observed excess of events over the expected background has a significance of 8.2 standard deviations.
Abstract: This Letter describes the observation of the light-by-light scattering process, γγ→γγ, in Pb+Pb collisions at sqrt[s_{NN}]=5.02 TeV. The analysis is conducted using a data sample corresponding to an integrated luminosity of 1.73 nb^{-1}, collected in November 2018 by the ATLAS experiment at the LHC. Light-by-light scattering candidates are selected in events with two photons produced exclusively, each with transverse energy E_{T}^{γ}>3 GeV and pseudorapidity |η_{γ}|<2.4, diphoton invariant mass above 6 GeV, and small diphoton transverse momentum and acoplanarity. After applying all selection criteria, 59 candidate events are observed for a background expectation of 12±3 events. The observed excess of events over the expected background has a significance of 8.2 standard deviations. The measured fiducial cross section is 78±13(stat)±7(syst)±3(lumi) nb.
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University of Pennsylvania1, University of Chicago2, University of Queensland3, Lawrence Berkeley National Laboratory4, Australian National University5, University of Portsmouth6, University of Southampton7, University of Copenhagen8, Korea Astronomy and Space Science Institute9, Harvard University10, African Institute for Mathematical Sciences11, Texas A&M University12, Pontifical Catholic University of Chile13, University of California, Berkeley14, University of California, Santa Cruz15, University of Pittsburgh16, Swinburne University of Technology17, University of Namibia18, Gordon and Betty Moore Foundation19, Macquarie University20, Argonne National Laboratory21, University of Sydney22, University of Cambridge23, University of Arizona24, University of Illinois at Urbana–Champaign25, Fermilab26, National Institutes of Natural Sciences, Japan27, Academia Sinica28, Carnegie Institution for Science29, Institut d'Astrophysique de Paris30, University College London31, Stanford University32, SLAC National Accelerator Laboratory33, IFAE34, Spanish National Research Council35, Indian Institute of Technology, Hyderabad36, California Institute of Technology37, Autonomous University of Madrid38, ETH Zurich39, Ohio State University40, Max Planck Society41, Ludwig Maximilian University of Munich42, University of São Paulo43, University of Michigan44, University of Sussex45, Universidade Federal do Rio Grande do Sul46, Brandeis University47, State University of Campinas48, Oak Ridge National Laboratory49
TL;DR: In this paper, the analysis underpinning the measurement of cosmological parameters from 207 spectroscopically classified SNe Ia from the first 3 years of the DES-SN, spanning a redshift range of 0.017 < z < 0.849.
Abstract: We present the analysis underpinning the measurement of cosmological parameters from 207 spectroscopically classified SNe Ia from the first 3 years of the Dark Energy Survey Supernova Program (DES-SN), spanning a redshift range of 0.017 < z < 0.849. We combine the DES-SN sample with an external sample of 122 low-redshift (z < 0.1) SNe. Ia, resulting in a "DES-SN3YR" sample of 329 SNe Ia. Our cosmological analyses are blinded: after combining our DES-SN3YR distances with constraints from the Cosmic Microwave Background, our uncertainties in the measurement of the dark energy equation-of-state parameter, w, are 0.042. (stat) and 0.059 (stat+syst) at 68% confidence. We provide a detailed systematic uncertainty budget, which has nearly equal contributions from photometric calibration, astrophysical bias corrections, and instrumental bias corrections. We also include several new sources of systematic uncertainty. While our sample is less than one-third the size of the Pantheon sample, our constraints on w are only larger by 1.4x, showing the impact of the DES-SN. Ia light-curve quality. We find that the traditional stretch and color standardization parameters of the DES-SNe. Ia are in agreement with earlier SN. Ia samples such as Pan-STARRS1 and the Supernova Legacy Survey. However, we find smaller intrinsic scatter about the Hubble diagram (0.077 mag). Interestingly, we find no evidence for a Hubble residual step (0.007 +/- 0.018 mag) as a function of host-galaxy mass for the DES subset, in 2.4 sigma tension with previous measurements. We also present novel validation methods of our sample using simulated SNe. Ia inserted in DECam images and using large catalog-level simulations to test for biases in our analysis pipelines.
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Lawrence Berkeley National Laboratory1, École Polytechnique Fédérale de Lausanne2, Yale University3, University of Rochester4, University of Portsmouth5, National Tsing Hua University6, Aix-Marseille University7, Harvard University8, University of Arizona9, Durham University10, Universidad de Guanajuato11, CFA Institute12, Argonne National Laboratory13, Ohio State University14, University of California, Santa Cruz15, National Autonomous University of Mexico16, IFAE17, Tsinghua University18, University of Pittsburgh19, University of Waterloo20, IAC21, Ohio University22, University of Michigan23, Stanford University24, Shanghai Jiao Tong University25
TL;DR: The status of the DESI and its plans and opportunities for the coming decade are discussed in this paper, with a focus on wide field spectroscopy and the future of the instrument.
Abstract: We present the status of the Dark Energy Spectroscopic Instrument (DESI) and its plans and opportunities for the coming decade. DESI construction and its initial five years of operations are an approved experiment of the US Department of Energy and is summarized here as context for the Astro2020 panel. Beyond 2025, DESI will require new funding to continue operations. We expect that DESI will remain one of the world's best facilities for wide-field spectroscopy throughout the decade. More about the DESI instrument and survey can be found at this https URL.
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TL;DR: In this article, the electron and photon energy calibration obtained with the ATLAS detector using about 36 fb−1 of LHC proton-proton collision data recorded at √s=13 TeV in 2015 and 2016 is discussed.
Abstract: This paper presents the electron and photon energy calibration obtained with the ATLAS detector using about 36 fb−1 of LHC proton-proton collision data recorded at √s=13 TeV in 2015 and 2016. The different calibration steps applied to the data and the optimization of the reconstruction of electron and photon energies are discussed. The absolute energy scale is set using a large sample of Z boson decays into electron-positron pairs. The systematic uncertainty in the energy scale calibration varies between 0.03% to 0.2% in most of the detector acceptance for electrons with transverse momentum close to 45 GeV . For electrons with transverse momentum of 10 GeV the typical uncertainty is 0.3% to 0.8% and it varies between 0.25% and 1% for photons with transverse momentum around 60 GeV . Validations of the energy calibration with J/ψ → e+e− decays and radiative Z boson decays are also presented.
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TL;DR: In this paper, a search for heavy right-handed Majorana or Dirac neutrinos and heavy gauge bosons was performed in events with a pair of energetic electrons or muons, with the same or opposite conditions.
Abstract: A search for heavy right-handed Majorana or Dirac neutrinos N (R) and heavy right-handed gauge bosons W (R) is performed in events with a pair of energetic electrons or muons, with the same or oppo ...
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TL;DR: In this paper, the authors propose a scalar dark energy model using up to 37 fb(-1) = 13 TeV pp collision data collected by the ATLAS detector at the LHC during 2015-2016.
Abstract: Constraints on selected mediator-based dark matter models and a scalar dark energy model using up to 37 fb(-1) = 13 TeV pp collision data collected by the ATLAS detector at the LHC during 2015-2016 ...
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INAF1, University of Arizona2, University of California, Riverside3, Fermilab4, University of Michigan5, Stanford University6, SLAC National Accelerator Laboratory7, Santa Cruz Institute for Particle Physics8, University of Sussex9, Stony Brook University10, Carnegie Mellon University11, Ludwig Maximilian University of Munich12, Max Planck Society13, Rhodes University14, University College London15, Institute of Cosmology and Gravitation, University of Portsmouth16, National Center for Supercomputing Applications17, University of Illinois at Urbana–Champaign18, IFAE19, Spanish National Research Council20, Steward Health Care System21, California Institute of Technology22, University of Chicago23, Autonomous University of Madrid24, ETH Zurich25, Ohio State University26, Harvard University27, Australian Astronomical Observatory28, University of São Paulo29, University of Pennsylvania30, Texas A&M University31, Catalan Institution for Research and Advanced Studies32, Brookhaven National Laboratory33, University of Southampton34, Brandeis University35, State University of Campinas36, Oak Ridge National Laboratory37
TL;DR: In this paper, the authors derived cosmological constraints from the abundance and weak-lensing signal of clusters of richness in the red-shift range of the Sloan Digital Sky Survey (SDSS).
Abstract: We perform the first blind analysis of cluster abundance data. Specifically, we derive cosmological constraints from the abundance and weak-lensing signal of \redmapper\ clusters of richness $\lambda\geq 20$ in the redshift range $z\in[0.1,0.3]$ as measured in the Sloan Digital Sky Survey (SDSS). We simultaneously fit for cosmological parameters and the richness--mass relation of the clusters. For a flat $\Lambda$CDM cosmological model with massive neutrinos, we find $S_8 \equiv \sigma_{8}(\Omega_m/0.3)^{0.5}=0.79^{+0.05}_{-0.04}$. This value is both consistent and competitive with that derived from cluster catalogues selected in different wavelengths. Our result is also consistent with the combined probes analyses by the Dark Energy Survey (DES) and the Kilo-Degree Survey (KiDS), and with the Cosmic Microwave Background (CMB) anisotropies as measured by \planck. We demonstrate that the cosmological posteriors are robust against variation of the richness--mass relation model and to systematics associated with the calibration of the selection function. In combination with Baryon Acoustic Oscillation (BAO) data and Big-Bang Nucleosynthesis (BBN) data, we constrain the Hubble rate to be $h=0.66\pm 0.02$, independent of the CMB. Future work aimed at improving our understanding of the scatter of the richness--mass relation has the potential to significantly improve the precision of our cosmological posteriors. The methods described in this work were developed for use in the forthcoming analysis of cluster abundances in the DES. Our SDSS analysis constitutes the first part of a staged-unblinding analysis of the full DES data set.
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University of Southampton1, University of Pittsburgh2, Korea Astronomy and Space Science Institute3, Texas A&M University4, Spanish National Research Council5, Swinburne University of Technology6, SLAC National Accelerator Laboratory7, Stanford University8, University of Chicago9, Lawrence Berkeley National Laboratory10, Australian National University11, University of Pennsylvania12, Brandeis University13, Institut d'Astrophysique de Paris14, University College London15, Fermilab16, IFAE17, Indian Institute of Technology, Hyderabad18, Steward Health Care System19, California Institute of Technology20, Autonomous University of Madrid21, National Center for Supercomputing Applications22, University of Illinois at Urbana–Champaign23, ETH Zurich24, Santa Cruz Institute for Particle Physics25, Ohio State University26, Ludwig Maximilian University of Munich27, Max Planck Society28, Harvard University29, Macquarie University30, University of São Paulo31, University of Michigan32, Catalan Institution for Research and Advanced Studies33, University of Sussex34, State University of Campinas35, Oak Ridge National Laboratory36, Institute of Cosmology and Gravitation, University of Portsmouth37
TL;DR: In this paper, the authors presented a sample of 21 hydrogen-free superluminous supernovae (SLSNe-I) and one hydrogen-rich SLSN-II detected during the five-year Dark Energy Survey (DES).
Abstract: We present a sample of 21 hydrogen-free superluminous supernovae (SLSNe-I) and one
hydrogen-rich SLSN (SLSN-II) detected during the five-year Dark Energy Survey (DES).
These SNe, located in the redshift range 0.220 < z < 1.998, represent the largest homogeneously
selected sample of SLSN events at high redshift.We present the observed g, r, i, z light
curves for these SNe,which we interpolate using Gaussian processes. The resulting light curves
are analysed to determine the luminosity function of SLSNe-I, and their evolutionary timescales.
The DES SLSN-I sample significantly broadens the distribution of SLSN-I light-curve
properties when combined with existing samples from the literature. We fit a magnetar model
to our SLSNe, and find that this model alone is unable to replicate the behaviour of many of the
bolometric light curves.We search theDES SLSN-I light curves for the presence of initial peaks
prior to the main light-curve peak. Using a shock breakout model, our Monte Carlo search finds
that 3 of our 14 eventswith pre-max data display such initial peaks.However, 10 events showno
evidence for such peaks, in some cases downto an absolutemagnitude of<−16, suggesting that
such features are not ubiquitous to all SLSN-I events. We also identify a red pre-peak feature
within the light curve of one SLSN, which is comparable to that observed within SN2018bsz.
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University of Chicago1, University of Pennsylvania2, University of Queensland3, Lawrence Berkeley National Laboratory4, Australian National University5, University of Portsmouth6, University of Southampton7, University of Copenhagen8, Korea Astronomy and Space Science Institute9, Harvard University10, Pontifical Catholic University of Chile11, Space Telescope Science Institute12, University of California, Berkeley13, University of California, Santa Cruz14, Swinburne University of Technology15, University of Namibia16, Gordon and Betty Moore Foundation17, University of Sydney18, University of Cambridge19, University of Illinois at Urbana–Champaign20, National Institutes of Natural Sciences, Japan21, Academia Sinica22, Carnegie Institution for Science23, Fermilab24, Institut d'Astrophysique de Paris25, University College London26, Stanford University27, IFAE28, Spanish National Research Council29, Indian Institute of Technology, Hyderabad30, California Institute of Technology31, University of Arizona32, Autonomous University of Madrid33, University of Michigan34, ETH Zurich35, Ohio State University36, Macquarie University37, University of São Paulo38, Texas A&M University39, Brandeis University40, State University of Campinas41, Oak Ridge National Laboratory42
TL;DR: In this paper, catalogue-level simulations of Type Ia supernova (SN Ia) light curves in the DES-SN and in low-redshift samples from the Center for Astrophysics (CfA) and the Carnegie Supernova Project (CSP) were used to model biases from selection effects and light-curve analysis and to determine bias corrections for SN Ia distance moduli that are used to measure cosmological parameters.
Abstract: We describe catalogue-level simulations of Type Ia supernova (SN Ia) light curves in the Dark Energy Survey Supernova Program (DES-SN) and in low-redshift samples from the Center for Astrophysics (CfA) and the Carnegie Supernova Project (CSP). These simulations are used to model biases from selection effects and light-curve analysis and to determine bias corrections for SN Ia distance moduli that are used to measure cosmological parameters. To generate realistic light curves, the simulation uses a detailed SN Ia model, incorporates information from observations (point spread function, sky noise, zero-point), and uses summary information (e.g. detection efficiency versus signal-to-noise ratio) based on 10 000 fake SN light curves whose fluxes were overlaid on images and processed with our analysis pipelines. The quality of the simulation is illustrated by predicting distributions observed in the data. Averaging within redshift bins, we find distance modulus biases up to 0.05 mag over the redshift ranges of the low-z and DES-SN samples. For individual events, particularly those with extreme red or blue colour, distance biases can reach 0.4 mag. Therefore, accurately determining bias corrections is critical for precision measurements of cosmological parameters. Files used to make these corrections are available at https://des.ncsa.illinois.edu/releases/sn.
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TL;DR: In this article, a measurement of the extragalactic background light (EBL) based on a joint likelihood analysis of 32 gamma-ray spectra for 12 blazars in the redshift range was presented.
Abstract: We present a measurement of the extragalactic background light (EBL) based on a joint likelihood analysis of 32 gamma-ray spectra for 12 blazars in the redshift range z = 003–0944, obtained by the MAGIC telescopes and Fermi-LAT The EBL is the part of the diffuse extragalactic radiation spanning the ultraviolet, visible, and infrared bands Major contributors to the EBL are the light emitted by stars through the history of the Universe, and the fraction of it that was absorbed by dust in galaxies and re-emitted at longer wavelengthsThe EBL can be studied indirectly through its effect on very high energy photons that are emitted by cosmic sources and absorbed via γγ interactions during their propagation across cosmological distances We obtain estimates of the EBL density in good agreement with state-of-the-art models of the EBL production and evolution The 1σ upper bounds, including systematic uncertainties, are between 13 per cent and 23 per cent above the nominal EBL density in the models No anomaly in the expected transparency of the Universe to gamma-rays is observed in any range of optical depth We also perform a wavelength-resolved EBL determination, which results in a hint of an excess of EBL in the 018–062 |$\mu\mathrm{ m}$| range relative to the studied models, yet compatible with them within systematics
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TL;DR: In this paper, the authors present measurements of W +/- Z production cross sections in pp collisions at a centre-of-mass energy of 13TeV, collected in 2015 and 2016 by the ATLAS experiment at the L...
Abstract: This paper presents measurements of W +/- Z production cross sections in pp collisions at a centre-of-mass energy of 13TeV. The data were collected in 2015 and 2016 by the ATLAS experiment at the L ...
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TL;DR: In this article, the performance of taggers for hadronically decaying top quarks and W bosons in pp collisions at s = 13 TeV recorded by the ATLAS experiment at the Large Hadron Collider is presented.
Abstract: The performance of identification algorithms (“taggers”) for hadronically decaying top quarks and W bosons in pp collisions at s = 13 TeV recorded by the ATLAS experiment at the Large Hadron Collider is presented. A set of techniques based on jet shape observables are studied to determine a set of optimal cut-based taggers for use in physics analyses. The studies are extended to assess the utility of combinations of substructure observables as a multivariate tagger using boosted decision trees or deep neural networks in comparison with taggers based on two-variable combinations. In addition, for highly boosted top-quark tagging, a deep neural network based on jet constituent inputs as well as a re-optimisation of the shower deconstruction technique is presented. The performance of these taggers is studied in data collected during 2015 and 2016 corresponding to 36.1 fb - 1 for the tt¯ and γ+ jet and 36.7 fb - 1 for the dijet event topologies. © 2019, CERN for the benefit of the ATLAS collaboration.
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TL;DR: A search for doubly charged scalar bosons decaying into W boson pairs using a data sample collected by the ATLAS detector at the LHC at a centre-of-mass energy of 13 TeV in 2015 and 2016 finds no significant deviations from the Standard Model predictions.
Abstract: A search for doubly charged scalar bosons decaying into W boson pairs is presented. It uses a data sample from proton–proton collisions corresponding to an integrated luminosity of 36.1 fb$^\mathrm {-1}$ collected by the ATLAS detector at the LHC at a centre-of-mass energy of 13 TeV in 2015 and 2016. This search is guided by a model that includes an extension of the Higgs sector through a scalar triplet, leading to a rich phenomenology that includes doubly charged scalar bosons $H^{\pm \pm }$ . Those bosons are produced in pairs in proton–proton collisions and decay predominantly into electroweak gauge bosons $H^{\pm \pm }\rightarrow W^{\pm } W^{\pm }$ . Experimental signatures with several leptons, missing transverse energy and jets are explored. No significant deviations from the Standard Model predictions are found. The parameter space of the benchmark model is excluded at 95% confidence level for $H^{\pm \pm }$ bosons with masses between 200 and 220 GeV.
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Princeton University1, University of Cambridge2, University of California, Riverside3, Ohio State University4, Carnegie Institution for Science5, Fermilab6, Institute of Cosmology and Gravitation, University of Portsmouth7, Institut d'Astrophysique de Paris8, University College London9, National Center for Supercomputing Applications10, University of Illinois at Urbana–Champaign11, IFAE12, Spanish National Research Council13, Stanford University14, University of Pennsylvania15, Indian Institute of Technology, Hyderabad16, University of Michigan17, University of Chicago18, Autonomous University of Madrid19, SLAC National Accelerator Laboratory20, Santa Cruz Institute for Particle Physics21, Max Planck Society22, Harvard University23, Macquarie University24, University of São Paulo25, Texas A&M University26, Catalan Institution for Research and Advanced Studies27, California Institute of Technology28, University of Southampton29, State University of Campinas30, Oak Ridge National Laboratory31, Argonne National Laboratory32
TL;DR: In this paper, a search for z > 6.5 quasars using the DES dataset combined with VISTA Hemisphere Survey (VHS) and WISE All-Sky Survey was conducted.
Abstract: We report the results from a search for z > 6.5 quasars using the Dark Energy Survey (DES) Year 3 dataset combined with the VISTA Hemisphere Survey (VHS) and WISE All-Sky Survey. Our photometric selection method is shown to be highly efficient in identifying clean samples of high-redshift quasars leading to spectroscopic confirmation of three new quasars - VDESJ 0244-5008 (z=6.724), VDESJ 0020-3653 (z=6.834) and VDESJ 0246-5219 (z=6.90) - which were selected as the highest priority candidates in the survey data without any need for additional follow-up observations. The new quasars span the full range in luminosity covered by other z>6.5 quasar samples (J AB = 20.2 to 21.3; M1450 = -25.6 to -26.6). We have obtained spectroscopic observations in the near infrared for VDESJ 0244-5008 and VDESJ 0020-3653 as well as our previously identified quasar, VDESJ 0224-4711 at z=6.50 from Reed et al. (2017). We use the near infrared spectra to derive virial black-hole masses from the full-width-half-maximum of the MgII line. These black-hole masses are ~ 1 - 2 x 10$^9$M$_\odot$. Combining with the bolometric luminosities of these quasars of L$_{\rm{bol}}\simeq$ 1 - 3 x 10$^{47}$implies that the Eddington ratios are high - $\simeq$0.6-1.1. We consider the C\textrm{\textsc{IV}} emission line properties of the sample and demonstrate that our high-redshift quasars do not have unusual C\textrm{\textsc{IV}} line properties when compared to carefully matched low-redshift samples. Our new DES+VHS $z>6.5$ quasars now add to the growing census of luminous, rapidly accreting supermassive black-holes seen well into the epoch of reionisation.
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TL;DR: In this paper, single and double-differential cross-section measurements for the production of top-quark pairs, in the lepton + jets channel at particle and parton level, are presented.
Abstract: Single- and double-differential cross-section measurements are presented for the production of top-quark pairs, in the lepton + jets channel at particle and parton level. Two topologies, resolved a ...
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University of Pennsylvania1, University of Chicago2, University of Queensland3, Lawrence Berkeley National Laboratory4, University of Portsmouth5, Australian National University6, University of Southampton7, Stanford University8, Fermilab9, African Institute for Mathematical Sciences10, Texas A&M University11, Spanish National Research Council12, University of California, Santa Cruz13, University of Pittsburgh14, University of Namibia15, University of Illinois at Urbana–Champaign16, National Institutes of Natural Sciences, Japan17, Academia Sinica18, Institut d'Astrophysique de Paris19, University College London20, SLAC National Accelerator Laboratory21, IFAE22, Indian Institute of Technology, Hyderabad23, California Institute of Technology24, University of Arizona25, Autonomous University of Madrid26, University of Michigan27, ETH Zurich28, Ohio State University29, Harvard University30, Macquarie University31, University of São Paulo32, Brandeis University33, State University of Campinas34, Oak Ridge National Laboratory35
TL;DR: In this article, the authors present griz light curves of 251 SNe Ia from the first 3 years of the DES-SN spectroscopically classified sample, which are used in the cosmological parameter analysis by employing a scene modeling approach that simultaneously models a variable transient flux and temporally constant host galaxy.
Abstract: We present griz light curves of 251 SNe Ia from the first 3 years of the Dark Energy Survey Supernova Program's (DES-SN) spectroscopically classified sample. The photometric pipeline described in this paper produces the calibrated fluxes and associated uncertainties used in the cosmological parameter analysis by employing a scene modeling approach that simultaneously models a variable transient flux and temporally constant host galaxy. We inject artificial point sources onto DECam images to test the accuracy of our photometric method. Upon comparison of input and measured artificial supernova fluxes, we find that flux biases peak at 3 mmag. We require corrections to our photometric uncertainties as a function of host galaxy surface brightness at the transient location, similar to that seen by the DES Difference Imaging Pipeline used to discover transients. The public release of the light curves can be found at https://des.ncsa.illinois.edu/releases/sn.
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Fermilab1, Stanford University2, Liverpool John Moores University3, University of KwaZulu-Natal4, University of Portsmouth5, Institut d'Astrophysique de Paris6, University College London7, University of Illinois at Urbana–Champaign8, IFAE9, University of Pennsylvania10, Indian Institute of Technology, Hyderabad11, Ludwig Maximilian University of Munich12, California Institute of Technology13, University of Arizona14, University of Michigan15, Spanish National Research Council16, Autonomous University of Madrid17, ETH Zurich18, University of California, Santa Cruz19, Ohio State University20, Max Planck Society21, Harvard University22, Macquarie University23, University of São Paulo24, Texas A&M University25, University of Sussex26, University of Southampton27, Brandeis University28, State University of Campinas29, Oak Ridge National Laboratory30
TL;DR: In this article, the authors reported the detection of intracluster light (ICL) with 300 galaxy clusters in the redshift range of 0.2-0.3.
Abstract: Using data collected by the Dark Energy Survey (DES), we report the detection of intracluster light (ICL) with ~300 galaxy clusters in the redshift range of 0.2–0.3. We design methods to mask detected galaxies and stars in the images and stack the cluster light profiles, while accounting for several systematic effects (sky subtraction, instrumental point-spread function, cluster selection effects, and residual light in the ICL raw detection from background and cluster galaxies). The methods allow us to acquire high signal-to-noise measurements of the ICL and central galaxies (CGs), which we separate with radial cuts. The ICL appears as faint and diffuse light extending to at least 1 Mpc from the cluster center, reaching a surface brightness level of 30 mag arcsec−2. The ICL and the cluster CG contribute 44% ± 17% of the total cluster stellar luminosity within 1 Mpc. The ICL color is overall consistent with that of the cluster red sequence galaxies, but displays the trend of becoming bluer with increasing radius. The ICL demonstrates an interesting self-similarity feature—for clusters in different richness ranges, their ICL radial profiles are similar after scaling with cluster R 200m , and the ICL brightness appears to be a good tracer of the cluster radial mass distribution. These analyses are based on the DES redMaPPer cluster sample identified in the first year of observations.
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TL;DR: In this article, the authors describe a strategy for a general search used by the ATLAS Collaboration to find potential indications of new physics, where events are classified according to their final state into many eve...
Abstract: This paper describes a strategy for a general search used by the ATLAS Collaboration to find potential indications of new physics. Events are classified according to their final state into many eve ...
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University of Pennsylvania1, Stanford University2, University of Chicago3, Cornell University4, Argonne National Laboratory5, Ludwig Maximilian University of Munich6, University of KwaZulu-Natal7, Brookhaven National Laboratory8, University of Arizona9, Max Planck Society10, Ohio State University11, Princeton University12, Fermilab13, Pierre-and-Marie-Curie University14, Institut d'Astrophysique de Paris15, University of Toronto16, University of Missouri–Kansas City17, University College London18, University of Illinois at Urbana–Champaign19, IFAE20, Spanish National Research Council21, Indian Institute of Technology, Hyderabad22, California Institute of Technology23, University of Michigan24, Autonomous University of Madrid25, University of Melbourne26, ETH Zurich27, University of California, Santa Cruz28, Florida State University29, Rutgers University30, Harvard University31, Lawrence Berkeley National Laboratory32, Macquarie University33, University of São Paulo34, Texas A&M University35, Pontifical Catholic University of Chile36, University of Milan37, Yale University38, Haverford College39, University of Colorado Boulder40, Ames Research Center41, University of Sussex42, University of Southampton43, Brandeis University44, State University of Campinas45, Oak Ridge National Laboratory46, University of Portsmouth47, Goddard Space Flight Center48
TL;DR: In this article, the authors measured the splashback feature in clusters selected via the SZ effect in data from the South Pole Telescope SZ survey and the Atacama Cosmology Telescope Polarimeter survey.
Abstract: We present a detection of the splashback feature around galaxy clusters selected using the Sunyaev–Zel’dovich (SZ) signal. Recent measurements of the splashback feature around optically selected galaxy clusters have found that the splashback radius, rsp, is smaller than predicted by N-body simulations. A possible explanation for this discrepancy is that rsp inferred from the observed radial distribution of galaxies is affected by selection effects related to the optical cluster-finding algorithms. We test this possibility by measuring the splashback feature in clusters selected via the SZ effect in data from the South Pole Telescope SZ survey and the Atacama Cosmology Telescope Polarimeter survey. The measurement is accomplished by correlating these cluster samples with galaxies detected in the Dark Energy Survey Year 3 data. The SZ observable used to select clusters in this analysis is expected to have a tighter correlation with halo mass and to be more immune to projection effects and aperture-induced biases, potentially ameliorating causes of systematic error for optically selected clusters. We find that the measured rsp for SZ-selected clusters is consistent with the expectations from simulations, although the small number of SZ-selected clusters makes a precise comparison difficult. In agreement with previous work, when using optically selected redMaPPer clusters with similar mass and redshift distributions, rsp is ∼2σ smaller than in the simulations. These results motivate detailed investigations of selection biases in optically selected cluster catalogues and exploration of the splashback feature around larger samples of SZ-selected clusters. Additionally, we investigate trends in the galaxy profile and splashback feature as a function of galaxy colour, finding that blue galaxies have profiles close to a power law with no discernible splashback feature, which is consistent with them being on their first infall into the cluster.
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TL;DR: In this paper, the authors performed searches for scalar leptoquarks pair-produced in proton-proton collisions at the Large Hadron Collider (LHC) at the ATLAS experiment.
Abstract: Searches for scalar leptoquarks pair-produced in proton–proton collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider are performed by the ATLAS experiment. A data set corresponding to an integrated luminosity of 36.1 fb$^{-1}$ is used. Final states containing two electrons or two muons and two or more jets are studied, as are states with one electron or muon, missing transverse momentum and two or more jets. No statistically significant excess above the Standard Model expectation is observed. The observed and expected lower limits on the leptoquark mass at 95% confidence level extend up to 1.29 TeV and 1.23 TeV for first- and second-generation leptoquarks, respectively, as postulated in the minimal Buchmuller–Ruckl–Wyler model, assuming a branching ratio into a charged lepton and a quark of 50%. In addition, measurements of particle-level fiducial and differential cross sections are presented for the $Z\rightarrow ee$ , $Z\rightarrow \mu \mu $ and $t\bar{t}$ processes in several regions related to the search control regions. Predictions from a range of generators are compared with the measurements, and good agreement is seen for many of the observables. However, the predictions for the $Z\rightarrow \ell \ell $ measurements in observables sensitive to jet energies disagree with the data.