Showing papers by "IFAE published in 2018"
TL;DR: The first public data release of the DES DR1 dataset is described in this paper, consisting of reduced single-epoch images, co-add images, and co-added source catalogs, and associated products and services.
Abstract: We describe the first public data release of the Dark Energy Survey, DES DR1, consisting of reduced single-epoch images, co-added images, co-added source catalogs, and associated products and services assembled over the first 3 yr of DES science operations. DES DR1 is based on optical/near-infrared imaging from 345 distinct nights (2013 August to 2016 February) by the Dark Energy Camera mounted on the 4 m Blanco telescope at the Cerro Tololo InterAmerican Observatory in Chile. We release data from the DES wide-area survey covering similar to 5000 deg(2) of the southern Galactic cap in five broad photometric bands, grizY. DES DR1 has a median delivered point-spread function of g = 1.12, r = 0.96, i = 0.88, z = 0.84, and Y = 0.'' 90 FWHM, a photometric precision of <1% in all bands, and an astrometric precision of 151 mas. The median co-added catalog depth for a 1.'' 95 diameter aperture at signal-to-noise ratio (S/N) = 10 is g = 24.33, r = 24.08, i = 23.44, z = 22.69, and Y = 21.44 mag. DES DR1 includes nearly 400 million distinct astronomical objects detected in similar to 10,000 co-add tiles of size 0.534 deg(2) produced from similar to 39,000 individual exposures. Benchmark galaxy and stellar samples contain similar to 310 million and similar to 80 million objects, respectively, following a basic object quality selection. These data are accessible through a range of interfaces, including query web clients, image cutout servers, jupyter notebooks, and an interactive co-add image visualization tool. DES DR1 constitutes the largest photometric data set to date at the achieved depth and photometric precision.
506 citations
TL;DR: In this paper, a search for new phenomena in final states with an energetic jet and large missing transverse momentum is reported, and the results are translated into exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, and supersymmetric particles in several compressed scenarios.
Abstract: Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton-proton collision data corresponding to an integrated luminosity of 36.1 fb−1 at a centre-of-mass energy of 13 TeV collected in 2015 and 2016 with the ATLAS detector at the Large Hadron Collider. Events are required to have at least one jet with a transverse momentum above 250 GeV and no leptons (e or μ). Several signal regions are considered with increasing requirements on the missing transverse momentum above 250 GeV. Good agreement is observed between the number of events in data and Standard Model predictions. The results are translated into exclusion limits in models with pair-produced weakly interacting dark-matter candidates, large extra spatial dimensions, and supersymmetric particles in several compressed scenarios.
358 citations
University College London1, Rhodes University2, Fermilab3, École Polytechnique4, Ohio State University5, University of Chicago6, Carnegie Institution for Science7, University of Pennsylvania8, Institut d'Astrophysique de Paris9, SLAC National Accelerator Laboratory10, Stanford University11, University of Illinois at Urbana–Champaign12, National Center for Supercomputing Applications13, IFAE14, Spanish National Research Council15, Argonne National Laboratory16, Indian Institute of Technology, Hyderabad17, Ludwig Maximilian University of Munich18, University of Michigan19, Autonomous University of Madrid20, University of Cambridge21, ETH Zurich22, Max Planck Society23, University of Washington24, Santa Cruz Institute for Particle Physics25, California Institute of Technology26, Australian Astronomical Observatory27, University of Edinburgh28, University of São Paulo29, Texas A&M University30, Catalan Institution for Research and Advanced Studies31, University of Toronto32, Lawrence Berkeley National Laboratory33, University of Arizona34, University of Melbourne35, Brookhaven National Laboratory36, University of Southampton37, State University of Campinas38, Oak Ridge National Laboratory39, Institute of Cosmology and Gravitation, University of Portsmouth40
TL;DR: In this article, the authors combine Dark Energy Survey Year 1 clustering and weak lensing data with baryon acoustic oscillations and Big Bang nucleosynthesis experiments to constrain the Hubble constant.
Abstract: We combine Dark Energy Survey Year 1 clustering and weak lensing data with baryon acoustic oscillations and Big Bang nucleosynthesis experiments to constrain the Hubble constant. Assuming a flat ΛCDM model with minimal neutrino mass (∑m_ν = 0.06 eV), we find |$H_0=67.4^{+1.1}_{-1.2}\ \rm {km\,\rm s^{-1}\,\rm Mpc^{-1}}$| (68 per cent CL). This result is completely independent of Hubble constant measurements based on the distance ladder, cosmic microwave background anisotropies (both temperature and polarization), and strong lensing constraints. There are now five data sets that: (a) have no shared observational systematics; and (b) each constrains the Hubble constant with fractional uncertainty at the few-per cent level. We compare these five independent estimates, and find that, as a set, the differences between them are significant at the 2.5σ level (χ^2/dof = 24/11, probability to exceed = 1.1 per cent). Having set the threshold for consistency at 3σ, we combine all five data sets to arrive at |$H_0=69.3^{+0.4}_{-0.6}\ \rm {km\,\mathrm{ s}^{-1}\,\mathrm{ Mpc}^{-1}}$|.
263 citations
University of Valencia1, Aligarh Muslim University2, University of Turin3, Colorado State University4, Hampton University5, Fermilab6, Massachusetts Institute of Technology7, University of Pittsburgh8, Northwestern University9, University of Kentucky10, Virginia Tech11, Ghent University12, Queen Mary University of London13, Michigan State University14, Université Paris-Saclay15, University of South Carolina16, Thomas Jefferson National Accelerator Facility17, IFAE18, University of Wrocław19
TL;DR: In this paper, the neutrino properties are modeled as a nuclear model and its theoretical uncertainties play an important role in interpreting every result, which is essential to every phase of experimental analyses.
233 citations
National Center for Supercomputing Applications1, University of Illinois at Urbana–Champaign2, Stanford University3, Fermilab4, SLAC National Accelerator Laboratory5, Brookhaven National Laboratory6, Institut d'Astrophysique de Paris7, University of Pennsylvania8, IFAE9, University College London10, ETH Zurich11, Max Planck Society12, Austin Peay State University13, Rhodes University14, New York University15, Texas A&M University16, Indian Institute of Technology, Hyderabad17, Ludwig Maximilian University of Munich18, Ohio State University19, Autonomous University of Madrid20, University of Michigan21, University of Cambridge22, University of Washington23, Santa Cruz Institute for Particle Physics24, Australian Astronomical Observatory25, Argonne National Laboratory26, University of São Paulo27, Catalan Institution for Research and Advanced Studies28, Institut de Ciències de l'Espai29, University of Southampton30, State University of Campinas31, Princeton University32, California Institute of Technology33, University of Sussex34, Oak Ridge National Laboratory35
TL;DR: The Dark Energy Survey (DES) photometric data set Y3 GOLD as discussed by the authors contains nearly 5000 deg2 of grizY imaging in the south Galactic cap including nearly 390 million objects, with depth reaching a signal-to-noise ratio ∼10 for extended objects up to i AB ∼ 23.0, and top-of-the-atmosphere photometric uniformity 98% and purity >99% for galaxies with 19 < i AB < 22.5.
Abstract: We describe the Dark Energy Survey (DES) photometric data set assembled from the first three years of science operations to support DES Year 3 cosmologic analyses, and provide usage notes aimed at the broad astrophysics community. Y3 GOLD improves on previous releases from DES, Y1 GOLD, and Data Release 1 (DES DR1), presenting an expanded and curated data set that incorporates algorithmic developments in image detrending and processing, photometric calibration, and object classification. Y3 GOLD comprises nearly 5000 deg2 of grizY imaging in the south Galactic cap, including nearly 390 million objects, with depth reaching a signal-to-noise ratio ∼10 for extended objects up to i AB ∼ 23.0, and top-of-the-atmosphere photometric uniformity 98% and purity >99% for galaxies with 19 < i AB < 22.5. Additionally, it includes per-object quality information, and accompanying maps of the footprint coverage, masked regions, imaging depth, survey conditions, and astrophysical foregrounds that are used to select the cosmologic analysis samples.
231 citations
University of Chicago1, Fermilab2, University of Surrey3, Texas A&M University4, University of Cambridge5, INAF6, University of Illinois at Urbana–Champaign7, National Center for Supercomputing Applications8, Australian Astronomical Observatory9, SLAC National Accelerator Laboratory10, Stanford University11, Brookhaven National Laboratory12, University College London13, Rhodes University14, Institute of Cosmology and Gravitation, University of Portsmouth15, Autonomous University of Madrid16, Institut d'Astrophysique de Paris17, IFAE18, Spanish National Research Council19, University of Pennsylvania20, Indian Institute of Technology, Hyderabad21, University of Michigan22, ETH Zurich23, Ohio State University24, Max Planck Society25, Ludwig Maximilian University of Munich26, Harvard University27, California Institute of Technology28, Steward Health Care System29, Catalan Institution for Research and Advanced Studies30, University of Sussex31, Universidade Federal do Rio Grande do Sul32, University of Southampton33, State University of Campinas34, Oak Ridge National Laboratory35
TL;DR: In this article, the first 3 years of multiband optical imaging data from the Dark Energy Survey (DES) were used to perform a search for stellar streams around the Milky Way using a matched filter in color-magnitude space derived from a synthetic isochrone of an old, metal-poor stellar population.
Abstract: We perform a search for stellar streams around the Milky Way using the first 3 yr of multiband optical imaging data from the Dark Energy Survey (DES). We use DES data covering ∼5000 deg2 to a depth of g>23.5 with a relative photometric calibration uncertainty of <1%. This data set yields unprecedented sensitivity to the stellar density field in the southern celestial hemisphere, enabling the detection of faint stellar streams to a heliocentric distance of ∼50 kpc. We search for stellar streams using a matched filter in color–magnitude space derived from a synthetic isochrone of an old, metal-poor stellar population. Our detection technique recovers four previously known thin stellar streams: Phoenix, ATLAS, Tucana III, and a possible extension of Molonglo. In addition, we report the discovery of 11 new stellar streams. In general, the new streams detected by DES are fainter, more distant, and lower surface brightness than streams detected by similar techniques in previous photometric surveys. As a by-product of our stellar stream search, we find evidence for extratidal stellar structure associated with four globular clusters: NGC 288, NGC 1261, NGC 1851, and NGC 1904. The ever-growing sample of stellar streams will provide insight into the formation of the Galactic stellar halo, the Milky Way gravitational potential, and the large- and small-scale distribution of dark matter around the Milky Way.
213 citations
TL;DR: The performance of the missing transverse momentum reconstruction with the ATLAS detector is evaluated using data collected in proton–proton collisions at the LHC at a centre-of-mass energy of 13 TeV in 2015.
Abstract: The performance of the missing transverse momentum ( ETmiss ) reconstruction with the ATLAS detector is evaluated using data collected in proton-proton collisions at the LHC at a centre-of-mass energy of 13 TeV in 2015. To reconstruct ETmiss , fully calibrated electrons, muons, photons, hadronically decaying τ-leptons , and jets reconstructed from calorimeter energy deposits and charged-particle tracks are used. These are combined with the soft hadronic activity measured by reconstructed charged-particle tracks not associated with the hard objects. Possible double counting of contributions from reconstructed charged-particle tracks from the inner detector, energy deposits in the calorimeter, and reconstructed muons from the muon spectrometer is avoided by applying a signal ambiguity resolution procedure which rejects already used signals when combining the various ETmiss contributions. The individual terms as well as the overall reconstructed ETmiss are evaluated with various performance metrics for scale (linearity), resolution, and sensitivity to the data-taking conditions. The method developed to determine the systematic uncertainties of the ETmiss scale and resolution is discussed. Results are shown based on the full 2015 data sample corresponding to an integrated luminosity of 3.2fb-1 .
208 citations
TL;DR: In this article, a search was performed for resonant and non-resonant Higgs boson pair production in the $ \upgamma \ upgamma b\overline{b} $ final state.
Abstract: A search is performed for resonant and non-resonant Higgs boson pair production in the $ \upgamma \upgamma b\overline{b} $ final state. The data set used corresponds to an integrated luminosity of 36.1 fb$^{−1}$ of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. No significant excess relative to the Standard Model expectation is observed. The observed limit on the non-resonant Higgs boson pair cross-section is 0.73 pb at 95% confidence level. This observed limit is equivalent to 22 times the predicted Standard Model cross-section. The Higgs boson self-coupling (κ$_{λ}$ = λ$_{HHH}$/λ$_{HHH}^{SM}$ ) is constrained at 95% confidence level to −8.2 < κ$_{λ}$ < 13.2. For resonant Higgs boson pair production through $ X\to HH\to \upgamma \upgamma b\overline{b} $ , the limit is presented, using the narrow-width approximation, as a function of m$_{X}$ in the range 260 GeV < m$_{X}$ < 1000 GeV. The observed limits range from 1.1 pb to 0.12 pb over this mass range.
202 citations
TL;DR: In this paper, it was shown that a possible signature of the Standard Model Higgs instability is the production of gravitational waves sourced by Higgs fluctuations generated during inflation, and the two-point correlator of such gravitational waves by computing its amplitude, the frequency at peak, the spectral index, as well as their three point correlators for various polarisations.
Abstract: A fundamental property of the Standard Model is that the Higgs potential becomes unstable at large values of the Higgs field. For the current central values of the Higgs and top masses, the instability scale is about $10^{11}$ GeV and therefore not accessible by colliders. We show that a possible signature of the Standard Model Higgs instability is the production of gravitational waves sourced by Higgs fluctuations generated during inflation. We fully characterise the two-point correlator of such gravitational waves by computing its amplitude, the frequency at peak, the spectral index, as well as their three-point correlators for various polarisations. We show that, depending on the Higgs and top masses, either LISA or the Einstein Telescope and Advanced-Ligo, could detect such stochastic background of gravitational waves. In this sense, collider and gravitational wave physics can provide fundamental and complementary informations. Furthermore, the consistency relation among the three- and the two-point correlators could provide an efficient tool to ascribe the detected gravitational waves to the Standard Model itself. Since the mechanism described in this paper might also be responsible for the generation of dark matter under the form of primordial black holes, this latter hypothesis may find its confirmation through the detection of gravitational waves.
202 citations
TL;DR: The T2K experiment measures muon neutrino disappearance and electron neutRino appearance in accelerator-produced neutrinos and antineutrino beams and obtained 2σ confidence interval for the CP-violating phase, δ_{CP, does not include the CP -conserving cases (δ_{ CP}=0, π).
Abstract: The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of $14.7(7.6)\times 10^{20}$ protons on target in neutrino (antineutrino) mode, 89 $
u_e$ candidates and 7 anti-$
u_e$ candidates were observed while 67.5 and 9.0 are expected for $\delta_{CP}=0$ and normal mass ordering. The obtained $2\sigma$ confidence interval for the $CP$ violating phase, $\delta_{CP}$, does not include the $CP$-conserving cases ($\delta_{CP}=0,\pi$). The best-fit values of other parameters are $\sin^2\theta_{23} = 0.526^{+0.032}_{-0.036}$ and $\Delta m^2_{32}=2.463\pm0.065\times10^{-3} \mathrm{eV}^2/c^4$.
196 citations
TL;DR: In this paper, the mass of the $W$ boson was measured based on proton-proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC.
Abstract: A measurement of the mass of the $W$ boson is presented based on proton-proton collision data recorded in 2011 at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC, and corresponding to 4.6 fb$^{-1}$ of integrated luminosity. The selected data sample consists of $7.8 \times 10^6$ candidates in the $W\rightarrow \mu
u$ channel and $5.9 \times 10^6$ candidates in the $W\rightarrow e
u$ channel. The $W$-boson mass is obtained from template fits to the reconstructed distributions of the charged lepton transverse momentum and of the $W$ boson transverse mass in the electron and muon decay channels, yielding \begin{eqnarray} m_W &=& 80370 \pm 7 \, (\textrm{stat.}) \pm 11 \, (\textrm{exp. syst.}) \pm 14 \, (\textrm{mod. syst.}) \, \textrm{MeV} &=& 80370 \pm 19 \, \textrm{MeV}, \end{eqnarray} where the first uncertainty is statistical, the second corresponds to the experimental systematic uncertainty, and the third to the physics-modelling systematic uncertainty. A measurement of the mass difference between the $W^+$ and $W^-$ bosons yields $m_{W^+}-m_{W^-} = -29 \pm 28$ MeV.
TL;DR: In this article, a neutrino with energy similar to 290 TeV was detected in coincidence with the BL Lac object TXS. 0506+056 during enhanced gamma-ray activity, with chance coincidence being rejected at similar to 3 sigma level.
Abstract: A neutrino with energy similar to 290 TeV, IceCube-170922A, was detected in coincidence with the BL Lac object TXS. 0506+056 during enhanced gamma-ray activity, with chance coincidence being rejected at similar to 3 sigma level. We monitored the object in the very-high-energy (VHE) band with the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes for similar to 41 hr from 1.3 to 40.4 days after the neutrino detection. Day-timescale variability is clearly resolved. We interpret the quasi-simultaneous neutrino and broadband electromagnetic observations with a novel one-zone lepto-hadronic model, based on interactions of electrons and protons co-accelerated in the jet with external photons originating from a slow-moving plasma sheath surrounding the faster jet spine. We can reproduce the multiwavelength spectra of TXS 0506+056 with neutrino rate and energy compatible with IceCube-170922A, and with plausible values for the jet power of similar to 10(45) - 4 x 10(46) erg s(-1). The steep spectrum observed by MAGIC is concordant with internal gamma gamma absorption above similar to 100 GeV entailed by photohadronic production of a similar to 290 TeV neutrino, corroborating a genuine connection between the multi-messenger signals. In contrast to previous predictions of predominantly hadronic emission from neutrino sources, the gamma-rays can be mostly ascribed to inverse Compton upscattering of external photons by accelerated electrons. The X-ray and VHE bands provide crucial constraints on the emission from both accelerated electrons and protons. We infer that the maximum energy of protons in the jet comoving frame can be in the range similar to 10(14) - 10(18) eV.
TL;DR: A search for the electroweak production of charginos, neutralinos and sleptons decaying into final states involving two or three electrons or muons is presented and stringent limits at 95% confidence level are placed on the masses of relevant supersymmetric particles.
Abstract: A search for the electroweak production of charginos, neutralinos and sleptons decaying into final states involving two or three electrons or muons is presented. The analysis is based on 36.1 fb$^{-1}$ of $\sqrt{s}=13$ TeV proton–proton collisions recorded by the ATLAS detector at the Large Hadron Collider. Several scenarios based on simplified models are considered. These include the associated production of the next-to-lightest neutralino and the lightest chargino, followed by their decays into final states with leptons and the lightest neutralino via either sleptons or Standard Model gauge bosons, direct production of chargino pairs, which in turn decay into leptons and the lightest neutralino via intermediate sleptons, and slepton pair production, where each slepton decays directly into the lightest neutralino and a lepton. No significant deviations from the Standard Model expectation are observed and stringent limits at 95% confidence level are placed on the masses of relevant supersymmetric particles in each of these scenarios. For a massless lightest neutralino, masses up to 580 GeV are excluded for the associated production of the next-to-lightest neutralino and the lightest chargino, assuming gauge-boson mediated decays, whereas for slepton-pair production masses up to 500 GeV are excluded assuming three generations of mass-degenerate sleptons.
TL;DR: In this article, the authors used the Self-Organizing Map $p(z)$ (SOMPZ) to assign individual weak lensing source galaxies from the Dark Energy Survey Year 3 Weak Lensing Source Catalogue to four tomographic bins and estimate the redshift distributions in these bins.
Abstract: Determining the distribution of redshifts of galaxies observed by wide-field photometric experiments like the Dark Energy Survey is an essential component to mapping the matter density field with gravitational lensing. In this work we describe the methods used to assign individual weak lensing source galaxies from the Dark Energy Survey Year 3 Weak Lensing Source Catalogue to four tomographic bins and to estimate the redshift distributions in these bins. As the first application of these methods to data, we validate that the assumptions made apply to the DES Y3 weak lensing source galaxies and develop a full treatment of systematic uncertainties. Our method consists of combining information from three independent likelihood functions: Self-Organizing Map $p(z)$ (SOMPZ), a method for constraining redshifts from galaxy photometry; clustering redshifts (WZ), constraints on redshifts from cross-correlations of galaxy density functions; and shear ratios (SR), which provide constraints on redshifts from the ratios of the galaxy-shear correlation functions at small scales. Finally, we describe how these independent probes are combined to yield an ensemble of redshift distributions encapsulating our full uncertainty. We calibrate redshifts with combined effective uncertainties of $\sigma_{\langle z \rangle}\sim 0.01$ on the mean redshift in each tomographic bin.
TL;DR: In this article, it was shown that a possible signature of the Standard Model Higgs instability is the production of gravitational waves sourced by Higgs fluctuations generated during inflation, and the two-point correlator of such gravitational waves by computing its amplitude, the frequency at peak, the spectral index, as well as their three point correlators for various polarisations.
Abstract: A fundamental property of the Standard Model is that the Higgs potential becomes unstable at large values of the Higgs field. For the current central values of the Higgs and top masses, the instability scale is about $10^{11}$ GeV and therefore not accessible by colliders. We show that a possible signature of the Standard Model Higgs instability is the production of gravitational waves sourced by Higgs fluctuations generated during inflation. We fully characterise the two-point correlator of such gravitational waves by computing its amplitude, the frequency at peak, the spectral index, as well as their three-point correlators for various polarisations. We show that, depending on the Higgs and top masses, either LISA or the Einstein Telescope and Advanced-Ligo, could detect such stochastic background of gravitational waves. In this sense, collider and gravitational wave physics can provide fundamental and complementary informations. Furthermore, the consistency relation among the three- and the two-point correlators could provide an efficient tool to ascribe the detected gravitational waves to the Standard Model itself. Since the mechanism described in this paper might also be responsible for the generation of dark matter under the form of primordial black holes, this latter hypothesis may find its confirmation through the detection of gravitational waves.
University of Edinburgh1, Brookhaven National Laboratory2, University of Manchester3, Ohio State University4, University of Pennsylvania5, SLAC National Accelerator Laboratory6, IFAE7, Fermilab8, University of Chicago9, National Center for Supercomputing Applications10, Ludwig Maximilian University of Munich11, California Institute of Technology12, University College London13, ETH Zurich14, Complutense University of Madrid15, University of Cambridge16, Max Planck Society17, Rhodes University18, Institut d'Astrophysique de Paris19, Spanish National Research Council20, Stanford University21, Indian Institute of Technology, Hyderabad22, University of Michigan23, Autonomous University of Madrid24, University of Washington25, Santa Cruz Institute for Particle Physics26, Australian Astronomical Observatory27, Argonne National Laboratory28, University of São Paulo29, Princeton University30, Catalan Institution for Research and Advanced Studies31, University of Portsmouth32, Lawrence Berkeley National Laboratory33, University of Sussex34, University of Southampton35, State University of Campinas36, Oak Ridge National Laboratory37
TL;DR: In this article, the authors present two galaxy shape catalogues from the Dark Energy Survey Year 1 data set, covering 1500 deg2 with a median redshift of 0.59.
Abstract: We present two galaxy shape catalogues from the Dark Energy Survey Year 1 data set, covering 1500 deg2 with a median redshift of 0.59. The catalogues cover two main fields: Stripe 82, and an area overlapping the South Pole Telescope survey region. We describe our data analysis process and in particular our shape measurement using two independent shear measurement pipelines, METACALIBRATION and IM3SHAPE. The METACALIBRATION catalogue uses a Gaussian model with an innovative internal calibration scheme, and was applied to riz bands, yielding 34.8M objects. The IM3SHAPE catalogue uses amaximum-likelihood bulge/disc model calibrated using simulations, and was applied to r-band data, yielding 21.9M objects. Both catalogues pass a suite of null tests that demonstrate their fitness for use in weak lensing science. We estimate the 1σ uncertainties in multiplicative shear calibration to be 0.013 and 0.025 for the METACALIBRATION and IM3SHAPE catalogues, respectively.
TL;DR: Combined 95% confidence-level upper limits are set on the production cross section for a range of vectorlike quark scenarios, significantly improving upon the reach of the individual searches.
Abstract: A combination of the searches for pair-produced vectorlike partners of the top and bottom quarks in various decay channels (T -> Zt/Wb/Ht, B -> Zb/Wt/Hb) is performed using 36.1 fb(-1) of pp ...
TL;DR: A search for doubly charged Higgs bosons with pairs of prompt, isolated, highly energetic leptons with the same electric charge is presented, fitting the dilepton mass spectra in several exclusive signal regions.
Abstract: A search for doubly charged Higgs bosons with pairs of prompt, isolated, highly energetic leptons with the same electric charge is presented. The search uses a proton–proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to 36.1 $$\text {fb}^{-1}$$
of integrated luminosity recorded in 2015 and 2016 by the ATLAS detector at the LHC. This analysis focuses on the decays $$H^{\pm \pm }\rightarrow e^{\pm }e^{\pm }$$
, $$H^{\pm \pm }\rightarrow e^{\pm }\mu ^{\pm }$$
and $$H^{\pm \pm }\rightarrow \mu ^{\pm }\mu ^{\pm }$$
, fitting the dilepton mass spectra in several exclusive signal regions. No significant evidence of a signal is observed and corresponding limits on the production cross-section and consequently a lower limit on $$m(H^{\pm \pm })$$
are derived at 95% confidence level. With $$\ell ^{\pm }\ell ^{\pm }=e^{\pm }e^{\pm }/\mu ^{\pm }\mu ^{\pm }/e^{\pm }\mu ^{\pm }$$
, the observed lower limit on the mass of a doubly charged Higgs boson only coupling to left-handed leptons varies from 770 to 870 GeV (850 GeV expected) for $$B(H^{\pm \pm }\rightarrow \ell ^{\pm }\ell ^{\pm })=100\%$$
and both the expected and observed mass limits are above 450 GeV for $$B(H^{\pm \pm }\rightarrow \ell ^{\pm }\ell ^{\pm })=10\%$$
and any combination of partial branching ratios.
TL;DR: In this paper, an upper bound of 0.0025% and 0.031% for the cross-section of the charged Higgs boson times the branching fraction in the range 4.2-4.5 pb was established for the mass range 90-160 GeV.
Abstract: Charged Higgs bosons produced either in top-quark decays or in association with a top-quark, subsequently decaying via H$^{±}$ → τ$^{±}$ν$_{τ}$, are searched for in 36.1 fb$^{−1}$ of proton-proton collision data at $ \sqrt{s}=13 $ TeV recorded with the ATLAS detector. Depending on whether the top-quark produced together with H$^{±}$ decays hadronically or leptonically, the search targets τ+jets and τ+lepton final states, in both cases with a hadronically decaying τ-lepton. No evidence of a charged Higgs boson is found. For the mass range of $ {m}_{H^{\pm }} $ = 90–2000 GeV, upper limits at the 95% confidence level are set on the production cross-section of the charged Higgs boson times the branching fraction $ \mathrm{\mathcal{B}}\left({H}^{\pm}\to {\tau}^{\pm }{
u}_{\tau}\right) $ in the range 4.2–0.0025 pb. In the mass range 90–160 GeV, assuming the Standard Model cross-section for $ t\overline{t} $ production, this corresponds to upper limits between 0.25% and 0.031% for the branching fraction $ \mathrm{\mathcal{B}}\left(t\to b{H}^{\pm}\right)\times \mathrm{\mathcal{B}}\left({H}^{\pm}\to {\tau}^{\pm }{
u}_{\tau}\right) $ .
TL;DR: A search for supersymmetric partners of quarks and gluons in final states containing hadronic jets and missing transverse momentum, but no electrons or muons, is presented in this article.
Abstract: A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing hadronic jets and missing transverse momentum, but no electrons or muons, is presented ...
TL;DR: In this paper, the authors presented a search for direct electroweak gaugino or gluino pair production with a chargino nearly mass-degenerate with a stable neutralino.
Abstract: This paper presents a search for direct electroweak gaugino or gluino pair production with a chargino nearly mass-degenerate with a stable neutralino. It is based on an integrated luminosity of 36.1 fb$^{−1}$ of pp collisions at $ \sqrt{s}=13 $ TeV collected by the ATLAS experiment at the LHC. The final state of interest is a disappearing track accompanied by at least one jet with high transverse momentum from initial-state radiation or by four jets from the gluino decay chain. The use of short track segments reconstructed from the innermost tracking layers significantly improves the sensitivity to short chargino lifetimes. The results are found to be consistent with Standard Model predictions. Exclusion limits are set at 95% confidence level on the mass of charginos and gluinos for different chargino lifetimes. For a pure wino with a lifetime of about 0.2 ns, chargino masses up to 460 GeV are excluded. For the strong production channel, gluino masses up to 1.65 TeV are excluded assuming a chargino mass of 460 GeV and lifetime of 0.2 ns.
University of Southampton1, University of Queensland2, University of California, Santa Cruz3, Swinburne University of Technology4, University of Pennsylvania5, University of Chicago6, Australian Astronomical Observatory7, University of Sydney8, Australian National University9, University of Portsmouth10, Chinese Academy of Sciences11, University College London12, Rhodes University13, Fermilab14, Stanford University15, SLAC National Accelerator Laboratory16, University of Illinois at Urbana–Champaign17, National Center for Supercomputing Applications18, IFAE19, Spanish National Research Council20, Steward Health Care System21, California Institute of Technology22, Autonomous University of Madrid23, ETH Zurich24, Ohio State University25, Harvard University26, University of São Paulo27, Brandeis University28, State University of Campinas29, Oak Ridge National Laboratory30, University of Michigan31
TL;DR: In this article, the results of a search for rapidly evolving transients in the Dark Energy Survey Supernova Programme were presented, including 72 events, including 37 transients with a spectroscopic redshift from host galaxy spectral features.
Abstract: We present the results of a search for rapidly evolving transients in the Dark Energy Survey Supernova Programme. These events are characterized by fast light-curve evolution (rise to peak in≲10 d and exponential decline in≲30 d after peak).We discovered 72 events, including 37 transients with a spectroscopic redshift from host galaxy spectral features. The 37 events increase the total number of rapid optical transients by more than a factor of two. They are found at a wide range of redshifts (0.05 M > -22.25). The multiband photometry is well fit by a blackbody up to few weeks after peak. The events appear to be hot (T ≈ 10 000-30 000 K) and large (R ≈ 10 - 2 × 10 cm) at peak, and generally expand and cool in time, though some events show evidence for a receding photosphere with roughly constant temperature. Spectra taken around peak are dominated by a blue featureless continuum consistent with hot, optically thick ejecta. We compare our events with a previously suggested physical scenario involving shock breakout in an optically thick wind surrounding a core-collapse supernova, we conclude that current models for such a scenario might need an additional power source to describe the exponential decline. We find that these transients tend to favour star-forming host galaxies, which could be consistent with a core-collapse origin. However, more detailed modelling of the light curves is necessary to determine their physical origin.
TL;DR: In this paper, the authors studied the elastic response of planar black hole solutions in a simple class of holographic models with broken translational invariance and showed that these modes have a mass gap controlled by an explicit source of the translational symmetry breaking.
Abstract: We study the elastic response of planar black hole (BH) solutions in a simple class of holographic models with broken translational invariance. We compute the transverse quasi-normal mode spectrum and the propagation speed of the lowest energy mode. We find that the speed of the lowest mode relates to the BH rigidity modulus as dictated by elasticity theory. This allows to identify these modes as transverse phonons — the pseudo Goldstone bosons of spontaneously broken translational invariance. In addition, we show that these modes have a mass gap controlled by an explicit source of the translational symmetry breaking. These results provide a new confirmation that the BHs in these models do exhibit solid properties that become more manifest at low temperatures. Also, by the AdS/CFT correspondence, this allows to extend the standard results from the effective field theory for solids to quantum-critical materials.
TL;DR: It is shown that a cosmological signature of an instability of the standard model Higgs potential could be dark matter in the form of primordial black holes seeded by Higgs fluctuations during inflation.
Abstract: For the current central values of the Higgs boson and top quark masses, the standard model Higgs potential develops an instability at a scale of the order of 10^{11} GeV. We show that a cosmological signature of such instability could be dark matter in the form of primordial black holes seeded by Higgs fluctuations during inflation. The existence of dark matter might not require physics beyond the standard model.
TL;DR: In this paper, an angular analysis of the decay B-d(0) -> K*mu(+)mu(-) is presented, based on proton-proton collision data recorded by the ATLAS experiment at the LHC.
Abstract: An angular analysis of the decay B-d(0) -> K*mu(+)mu(-) is presented, based on proton-proton collision data recorded by the ATLAS experiment at the LHC. The study is using 20.3 fb(-1) of integra ...
National Center for Supercomputing Applications1, University of Illinois at Urbana–Champaign2, University of Cambridge3, Rhodes University4, University College London5, Institut d'Astrophysique de Paris6, Fermilab7, Institute of Cosmology and Gravitation, University of Portsmouth8, IFAE9, Stanford University10, University of Pennsylvania11, Texas A&M University12, Indian Institute of Technology, Hyderabad13, University of Chicago14, Autonomous University of Madrid15, SLAC National Accelerator Laboratory16, Ohio State University17, University of Washington18, Australian Astronomical Observatory19, Argonne National Laboratory20, University of São Paulo21, California Institute of Technology22, University of Michigan23, Brookhaven National Laboratory24, University of Southampton25, State University of Campinas26, Oak Ridge National Laboratory27
TL;DR: This paper performed a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey and 3-year Dark Energy Survey imaging, which provided light curves spanning more than 15 years.
Abstract: We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey and 3 Year Dark Energy Survey imaging, which provide light curves spanning more than 15 years. We identified ~1000 EVQs with a maximum change in g-band magnitude of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L bol ~ 1045–1047 erg s−1 and L/L Edd ~ 0.01–1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ~30%–50% among all $g\lesssim 22$ quasars over a baseline of ~15 yr. We performed detailed multi-wavelength, spectral, and variability analyses for the EVQs and compared them to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggests that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low rates, where the accretion flow is more likely to experience instabilities that drive the changes in flux by a factor of a few on multi-year timescales.
TL;DR: In this paper, a search for heavy resonances decaying into a pair of bosons leading to the final states, where $$\ell $$¯¯ stands for either an electron or a muon, is presented.
Abstract: A search for heavy resonances decaying into a pair of $$Z$$
bosons leading to $$\ell ^+\ell ^-\ell ^+\ell ^-$$
and $$\ell ^+\ell ^-
u \bar{
u }$$
final states, where $$\ell $$
stands for either an electron or a muon, is presented. The search uses proton–proton collision data at a centre-of-mass energy of 13
$$\text {TeV}$$
corresponding to an integrated luminosity of 36.1
$$\hbox {fb}^{-1}$$
collected with the ATLAS detector during 2015 and 2016 at the Large Hadron Collider. Different mass ranges for the hypothetical resonances are considered, depending on the final state and model. The different ranges span between 200 and 2000
$$\text {GeV}$$
. The results are interpreted as upper limits on the production cross section of a spin-0 or spin-2 resonance. The upper limits for the spin-0 resonance are translated to exclusion contours in the context of Type-I and Type-II two-Higgs-doublet models, while those for the spin-2 resonance are used to constrain the Randall–Sundrum model with an extra dimension giving rise to spin-2 graviton excitations.
TL;DR: A search for new heavy particles that decay into top-quark pairs is performed using data collected from proton–proton collisions at a centre-of-mass energy of 13 $$\text {TeV}$$TeV by the ATLAS detector at the Large Hadron Collider.
Abstract: A search for new heavy particles that decay into top-quark pairs is performed using data collected from proton-proton collisions at a centre-of-mass energy of 13 TeV by the ATLAS detector at the La ...
École Polytechnique Fédérale de Lausanne1, Fermilab2, University of California, Davis3, University of Chicago4, Stanford University5, Max Planck Society6, University of California, Los Angeles7, Andrés Bello National University8, Millennium Institute9, Valparaiso University10, European Southern Observatory11, University of Cambridge12, University College London13, Institut d'Astrophysique de Paris14, SLAC National Accelerator Laboratory15, National Center for Supercomputing Applications16, University of Illinois at Urbana–Champaign17, IFAE18, University of Pennsylvania19, Texas A&M University20, Indian Institute of Technology, Hyderabad21, Institut de Ciències de l'Espai22, Autonomous University of Madrid23, Lawrence Berkeley National Laboratory24, University of California, Berkeley25, Ohio State University26, University of Washington27, Australian Astronomical Observatory28, Argonne National Laboratory29, University of São Paulo30, Catalan Institution for Research and Advanced Studies31, California Institute of Technology32, University of Michigan33, University of Southampton34, State University of Campinas35, Oak Ridge National Laboratory36
TL;DR: The DES data management system is supported by the National Science Foundation under Grant Number AST-1138766 as mentioned in this paper, and the DES participants from Spanish institutions are partially supported by MINECO under grants AYA2015-71825, ESP2015-88861, FPA2015-68048, SEV-2012-0234, SEVERO-0249, and MDM-2015-0509, some of which include ERDF funds from the European Union.
Abstract: This work is supported by the Swiss National Science Foundation (SNSF). S. H. Suyu and D. C. Y. Chao thank the Max Planck Society for support through the Max Planck Research Group for SHS. T. Treu acknowledges support by the National Science Foundation through grant 1450141, by the Packard Foundation through a Packard Research Fellowship and by the UCLA Dean of Physical Sciences. K. Rojas is supported by Becas de Doctorado Nacional CONICYT 2017. T. Anguita and M. Chijani acknowledge support by proyecto FONDECYT 11130630 and by the Ministry for the Economy, Development, and Tourism’s Programa Inicativa Cientifica Milenio through grant IC 12009, awarded to The Millennium Institute of Astrophysics (MAS). M. Tewes acknowledges support from the DFG grant Hi 1495/2-1. J. Garcia-Bellido is supported by the Research Project FPA2015-68048 [MINECO-FEDER], and the Centro de Excelencia Severo Ochoa Program SEV-2012-0249. C. D. Fassnacht acknowledges support from the National Science Foundation grant AST-1312329 and from the UC Davis Physics Department and Dean of Math and Physical Sciences. Funding for the DES Projects has been provided by the US Department of Energy, the US National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, the Center for Cosmology and Astro-Particle Physics at the Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M 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 and the Ministerio da Ciencia, Tecnologia e Inovacao, the Deutsche Forschungsgemeinschaft and the Collaborating Institutions in the Dark Energy Survey ... The DES data management system is supported by the National Science Foundation under Grant Number AST-1138766. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2015-71825, ESP2015-88861, FPA2015-68048, SEV-2012-0234, SEV-2012-0249, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA programme of the Generalitat de Catalunya.
TL;DR: In this article, a search for neutral heavy resonances was performed in the WW -> e nu mu nu decay channel using collision data corresponding to an integrated luminosity of 36.1 fb(-1).
Abstract: A search for neutral heavy resonances is performed in the WW -> e nu mu nu decay channel using pp collision data corresponding to an integrated luminosity of 36.1 fb(-1), collected at a centre-o ...