Showing papers by "Bulgarian Academy of Sciences published in 2018"
TL;DR: It is shown that in the mentioned class of ESTGB theories there exist new black-hole solutions that are formed by spontaneous scalarization of the Schwarzschild black holes in the extreme curvature regime.
Abstract: In the present Letter, we consider a class of extended scalar-tensor-Gauss-Bonnet (ESTGB) theories for which the scalar degree of freedom is excited only in the extreme curvature regime. We show that in the mentioned class of ESTGB theories there exist new black-hole solutions that are formed by spontaneous scalarization of the Schwarzschild black holes in the extreme curvature regime. In this regime, below certain mass, the Schwarzschild solution becomes unstable and a new branch of solutions with a nontrivial scalar field bifurcates from the Schwarzschild one. As a matter of fact, more than one branch with a nontrivial scalar field can bifurcate at different masses, but only the first one is supposed to be stable. This effect is quite similar to the spontaneous scalarization of neutron stars. In contrast to the standard spontaneous scalarization of neutron stars, which is induced by the presence of matter, in our case, the scalarization is induced by the curvature of the spacetime.
455 citations
TL;DR: In this paper, the discriminating variables and the algorithms used for heavy-flavour jet identification during the first years of operation of the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, are presented.
Abstract: Many measurements and searches for physics beyond the standard model at the LHC rely on the efficient identification of heavy-flavour jets, i.e. jets originating from bottom or charm quarks. In this paper, the discriminating variables and the algorithms used for heavy-flavour jet identification during the first years of operation of the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, are presented. Heavy-flavour jet identification algorithms have been improved compared to those used previously at centre-of-mass energies of 7 and 8 TeV. For jets with transverse momenta in the range expected in simulated events, these new developments result in an efficiency of 68% for the correct identification of a b jet for a probability of 1% of misidentifying a light-flavour jet. The improvement in relative efficiency at this misidentification probability is about 15%, compared to previous CMS algorithms. In addition, for the first time algorithms have been developed to identify jets containing two b hadrons in Lorentz-boosted event topologies, as well as to tag c jets. The large data sample recorded in 2016 at a centre-of-mass energy of 13 TeV has also allowed the development of new methods to measure the efficiency and misidentification probability of heavy-flavour jet identification algorithms. The b jet identification efficiency is measured with a precision of a few per cent at moderate jet transverse momenta (between 30 and 300 GeV) and about 5% at the highest jet transverse momenta (between 500 and 1000 GeV).
454 citations
Harvard University1, University of Tübingen2, Max Planck Society3, Hungarian Academy of Sciences4, Howard Hughes Medical Institute5, University College Dublin6, University of Vienna7, University of Coimbra8, University of Ferrara9, University of Adelaide10, Trinity College, Dublin11, University of Cambridge12, Broad Institute13, Emory University14, University of Florence15, Bulgarian Academy of Sciences16, Danube Private University17, Romanian Academy18, Centre national de la recherche scientifique19, Eötvös Loránd University20, Sofia University21, University of Oxford22, University of Wyoming23, University of Zagreb24, Pennsylvania State University25, National Academy of Sciences of Ukraine26, Université de Montréal27, University of Bucharest28, Ludwig Maximilian University of Munich29, University of Edinburgh30, University of Wisconsin-Madison31, University of Palermo32, Croatian Academy of Sciences and Arts33, Naturhistorisches Museum34, Russian Academy of Sciences35, University of Toronto36, University of Latvia37, Durham University38, University of Hull39, Grand Valley State University40, Columbia University41
TL;DR: It is shown that southeastern Europe continued to be a nexus between east and west after the arrival of farmers, with intermittent genetic contact with steppe populations occurring up to 2,000 years earlier than the migrations from the steppe that ultimately replaced much of the population of northern Europe.
Abstract: Farming was first introduced to Europe in the mid-seventh millennium bc, and was associated with migrants from Anatolia who settled in the southeast before spreading throughout Europe. Here, to und ...
447 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
Martin Luther University of Halle-Wittenberg1, Zürcher Fachhochschule2, University of Bayreuth3, University of Picardie Jules Verne4, University of Oviedo5, Wageningen University and Research Centre6, Masaryk University7, University of Nottingham8, University of Rostock9, Max Planck Society10, Universidade Federal do Rio Grande do Sul11, University of North Carolina at Chapel Hill12, Santa Clara University13, Leiden University14, Academy of Sciences of the Czech Republic15, Shahjalal University of Science and Technology16, Sapienza University of Rome17, Natural Resources Canada18, Florida International University19, Universidade Federal do Acre20, Ghent University21, University of Göttingen22, University of the Basque Country23, Aarhus University24, Rocky Mountain Biological Laboratory25, Environmental Change Institute26, University of Nova Gorica27, Slovenian Academy of Sciences and Arts28, King Juan Carlos University29, Czech University of Life Sciences Prague30, VU University Amsterdam31, University of Würzburg32, National University of Cordoba33, National University of Saint Anthony the Abbot in Cuzco34, Wake Forest University35, University of Exeter36, Université du Québec en Abitibi-Témiscamingue37, University of Montpellier38, University of Adelaide39, University of Chile40, IFREMER41, University of British Columbia42, Universidade do Estado de Santa Catarina43, University of Münster44, University of Hamburg45, University of Wrocław46, University of Zurich47, Swiss Federal Institute for Forest, Snow and Landscape Research48, University of Oldenburg49, University of Wyoming50, University of Waikato51, Institut national de la recherche agronomique52, Sofia University53, Royal Botanic Gardens54, University of Edinburgh55, Landcare Research56, Radboud University Nijmegen57, Spanish National Research Council58, University of Barcelona59, University of Leeds60, University of Tartu61, University of Sydney62, University of Minnesota63, University of Jena64, University of La Serena65, Peking University66, Iwokrama International Centre for Rain Forest Conservation and Development67, Aristotle University of Thessaloniki68, Bulgarian Academy of Sciences69, University of Oulu70, University of Wisconsin–Eau Claire71, International Institute of Minnesota72, American Museum of Natural History73, Leipzig University74
TL;DR: It is shown that global trait composition is captured by two main dimensions that are only weakly related to macro-environmental drivers, which reflect the trade-offs at the species level but are weakly associated with climate and soil conditions at the global scale.
Abstract: Plant functional traits directly affect ecosystem functions. At the species level, trait combinations depend on trade-offs representing different ecological strategies, but at the community level trait combinations are expected to be decoupled from these trade-offs because different strategies can facilitate co-existence within communities. A key question is to what extent community-level trait composition is globally filtered and how well it is related to global versus local environmental drivers. Here, we perform a global, plot-level analysis of trait-environment relationships, using a database with more than 1.1 million vegetation plots and 26,632 plant species with trait information. Although we found a strong filtering of 17 functional traits, similar climate and soil conditions support communities differing greatly in mean trait values. The two main community trait axes that capture half of the global trait variation (plant stature and resource acquisitiveness) reflect the trade-offs at the species level but are weakly associated with climate and soil conditions at the global scale. Similarly, within-plot trait variation does not vary systematically with macro-environment. Our results indicate that, at fine spatial grain, macro-environmental drivers are much less important for functional trait composition than has been assumed from floristic analyses restricted to co-occurrence in large grid cells. Instead, trait combinations seem to be predominantly filtered by local-scale factors such as disturbance, fine-scale soil conditions, niche partitioning and biotic interactions.
349 citations
Albert M. Sirunyan1, Robin Erbacher2, C. A. Carrillo Montoya3, Wagner Carvalho4 +2355 more•Institutions (153)
TL;DR: In this paper, the performance of the modified system is studied using proton-proton collision data at center-of-mass energy √s=13 TeV, collected at the LHC in 2015 and 2016.
Abstract: The CMS muon detector system, muon reconstruction software, and high-level trigger underwent significant changes in 2013–2014 in preparation for running at higher LHC collision energy and instantaneous luminosity. The performance of the modified system is studied using proton-proton collision data at center-of-mass energy √s=13 TeV, collected at the LHC in 2015 and 2016. The measured performance parameters, including spatial resolution, efficiency, and timing, are found to meet all design specifications and are well reproduced by simulation. Despite the more challenging running conditions, the modified muon system is found to perform as well as, and in many aspects better than, previously. We dedicate this paper to the memory of Prof. Alberto Benvenuti, whose work was fundamental for the CMS muon detector.
303 citations
TL;DR: It is found that PARP1 mutations are tolerated in BRCA1 mutated cells, suggesting alternative resistance mechanisms and reinforces the importance of trappedPARP1 as a cytotoxic DNA lesion and suggests that PARp1 intramolecular interactions might influence PARPi-mediated cytotoxicity.
Abstract: Although PARP inhibitors (PARPi) target homologous recombination defective tumours, drug resistance frequently emerges, often via poorly understood mechanisms. Here, using genome-wide and high-density CRISPR-Cas9 “tag-mutate-enrich” mutagenesis screens, we identify close to full-length mutant forms of PARP1 that cause in vitro and in vivo PARPi resistance. Mutations both within and outside of the PARP1 DNA-binding zinc-finger domains cause PARPi resistance and alter PARP1 trapping, as does a PARP1 mutation found in a clinical case of PARPi resistance. This reinforces the importance of trapped PARP1 as a cytotoxic DNA lesion and suggests that PARP1 intramolecular interactions might influence PARPi-mediated cytotoxicity. PARP1 mutations are also tolerated in cells with a pathogenic BRCA1 mutation where they result in distinct sensitivities to chemotherapeutic drugs compared to other mechanisms of PARPi resistance (BRCA1 reversion, 53BP1, REV7 (MAD2L2) mutation), suggesting that the underlying mechanism of PARPi resistance that emerges could influence the success of subsequent therapies.
273 citations
TL;DR: Mechanisms and genes linking autophagy and AD, i.e., the mTOR pathway, neuroinflammation, endocannabinoid system, ATG7, BCL2, BECN1, CDK5, CLU, CTSD, FOXO1, GFAP, ITPR1, MAPT, PSEN1, SNCA, UBQLN 1, and UCHL1 are discussed.
Abstract: Alzheimer’s disease (AD) is the most common cause of progressive dementia in the elderly. It is characterized by a progressive and irreversible loss of cognitive abilities and formation of senile plaques, composed mainly of amyloid β (Aβ), and neurofibrillary tangles (NFTs), composed of tau protein, in the hippocampus and cortex of afflicted humans. In brains of AD patients the metabolism of Aβ is dysregulated, which leads to the accumulation and aggregation of Aβ. Metabolism of Aβ and tau proteins is crucially influenced by autophagy. Autophagy is a lysosome-dependent, homeostatic process, in which organelles and proteins are degraded and recycled into energy. Thus, dysfunction of autophagy is suggested to lead to the accretion of noxious proteins in the AD brain. In the present review, we describe the process of autophagy and its importance in AD. Additionally, we discuss mechanisms and genes linking autophagy and AD, i.e., the mTOR pathway, neuroinflammation, endocannabinoid system, ATG7, BCL2, BECN1, CDK5, CLU, CTSD, FOXO1, GFAP, ITPR1, MAPT, PSEN1, SNCA, UBQLN1, and UCHL1. We also present pharmacological agents acting via modulation of autophagy that may show promise in AD therapy. This review updates our knowledge on autophagy mechanisms proposing novel therapeutic targets for the treatment of AD.
268 citations
Humboldt University of Berlin1, Sapienza University of Rome2, University of Vermont3, European Forest Institute4, University of Freiburg5, Danish Nature Agency6, University of Forestry, Sofia7, University of Turin8, Forest Research Institute9, Mediterranean University10, University of Lisbon11, University of Zagreb12, Czech University of Life Sciences Prague13, Aleksandras Stulginskis University14, University of Trás-os-Montes and Alto Douro15, Saints Cyril and Methodius University of Skopje16, Swiss Federal Institute for Forest, Snow and Landscape Research17, University of Agriculture, Faisalabad18, University of Eastern Finland19, Bulgarian Academy of Sciences20
TL;DR: In this article, Sabatini et al. discuss the importance of gender diversity in soccer and discuss the role of gender in the sport of soccer in terms of sportswriting.
Abstract: Francesco Maria Sabatini1 | Sabina Burrascano2 | William S. Keeton3 | Christian Levers1 | Marcus Lindner4 | Florian Pötzschner1 | Pieter Johannes Verkerk5 | Jürgen Bauhus6 | Erik Buchwald7 | Oleh Chaskovsky8 | Nicolas Debaive9 | Ferenc Horváth10 | Matteo Garbarino11 | Nikolaos Grigoriadis12 | Fabio Lombardi13 | Inês Marques Duarte14 | Peter Meyer15 | Rein Midteng16 | Stjepan Mikac17 | Martin Mikoláš18 | Renzo Motta11 | Gintautas Mozgeris19 | Leónia Nunes14,20 | Momchil Panayotov21 | Peter Ódor10 | Alejandro Ruete22 | Bojan Simovski23 | Jonas Stillhard24 | Miroslav Svoboda18 | Jerzy Szwagrzyk25 | Olli-Pekka Tikkanen26 | Roman Volosyanchuk27 | Tomas Vrska28 | Tzvetan Zlatanov29 | Tobias Kuemmerle1
258 citations
TL;DR: In this article, a measurement of the H→ττ signal strength is performed using events recorded in proton-proton collisions by the CMS experiment at the LHC in 2016 at a center-of-mass energy of 13TeV.
250 citations
Albert M. Sirunyan1, Robin Erbacher2, C. A. Carrillo Montoya3, Wagner Carvalho4 +2283 more•Institutions (140)
TL;DR: These are the first direct limits for N mass above 500 GeV and the first limits obtained at a hadron collider for N masses below 40 Ge V.
Abstract: A search for a heavy neutral lepton N of Majorana nature decaying into a W boson and a charged lepton is performed using the CMS detector at the LHC. The targeted signature consists of three prompt charged leptons in any flavor combination of electrons and muons. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV, with an integrated luminosity of 35.9 fb^(−1). The search is performed in the N mass range between 1 GeV and 1.2 TeV. The data are found to be consistent with the expected standard model background. Upper limits are set on the values of |V_(eN)|^2and |V_(μN)|^2, where V_(lN) is the matrix element describing the mixing of N with the standard model neutrino of flavor l. These are the first direct limits for N masses above 500 GeV and the first limits obtained at a hadron collider for N masses below 40 GeV.
University of Oxford1, Katholieke Universiteit Leuven2, UK Astronomy Technology Centre3, Max Planck Society4, University of Sheffield5, University of Michigan6, Austrian Academy of Sciences7, University of Bonn8, University of La Serena9, Spanish National Research Council10, University of La Laguna11, University of Amsterdam12, Queen's University Belfast13, University of Surrey14, Radboud University Nijmegen15, National Research Council16, University of Chile17, Bulgarian Academy of Sciences18, Ludwig Maximilian University of Munich19, Keele University20, Armagh Observatory21, Johns Hopkins University22, Space Telescope Science Institute23
TL;DR: In this article, the authors determined the recent formation history and the initial mass function (IMF) of massive stars in 30 Doradus on the basis of spectroscopic observations of 247 stars more massive than 15 solar masses.
Abstract: The 30 Doradus star-forming region in the Large Magellanic Cloud is a nearby analog of large star-formation events in the distant universe. We determined the recent formation history and the initial mass function (IMF) of massive stars in 30 Doradus on the basis of spectroscopic observations of 247 stars more massive than 15 solar masses (Embedded Image). The main episode of massive star formation began about 8 million years (My) ago, and the star-formation rate seems to have declined in the last 1 My. The IMF is densely sampled up to 200 Embedded Image and contains 32 ± 12% more stars above 30 Embedded Image than predicted by a standard Salpeter IMF. In the mass range of 15 to 200 Embedded Image, the IMF power-law exponent is Embedded Image, shallower than the Salpeter value of 2.35.
TL;DR: It is shown that a cobalt ion is just barely affected by two linearly coordinated carbon ligands and, as such, exhibits maximal orbital angular momentum, an essential property for applications such as information storage and high-coercivity magnets.
Abstract: INTRODUCTION The magnetic properties of a single metal center are determined by a combination of its total spin S and orbital angular momentum L . Orbital angular momentum gives rise to magnetic anisotropy, an essential property for applications such as information storage and high-coercivity magnets. Unquenched L arises from an odd number of electrons in degenerate orbitals and is typically observed only for free ions, as well as for complexes of the f elements. For the majority of transition metal ions, however, orbital angular momentum is quenched by the ligand field, which removes the requisite orbital degeneracies. Maximal L for a transition metal ( L = 3) would require an odd number of electrons in two sets of degenerate orbitals. Such a species would entail a non-Aufbau configuration, wherein the electrons do not fill the d orbitals in the usual order of lowest to highest in energy, and likely exhibit a large magnetic anisotropy. RATIONALE Previous efforts have identified the utility of linear coordination environments for isolating iron complexes with unquenched orbital angular momentum and large magnetic anisotropies. Crucially, transition metals in this environment are unaffected by Jahn-Teller distortions that would otherwise remove orbital degeneracies in the case of partially filled d orbitals. Separately, cobalt atoms deposited on a MgO surface—for which one-coordination of the metal is achieved, provided a vacuum is maintained—were shown to have L = 3, giving rise to near-maximal magnetic anisotropy. Calculations on the hypothetical linear molecule Co(C(SiMe 3 ) 3 ) 2 (where Me is methyl) also predicted that this system would possess a ground state with L = 3. Empirically, maximal L in a transition metal complex thus requires both a linear coordination environment and a sufficiently weak ligand field strength to allow for non-Aufbau electron filling. RESULTS The strongly reducing nature of the carbanion ligand hinders isolation of dialkyl cobalt(II) complexes. However, reducing the basicity of the central carbanion through the use of electron-withdrawing aryloxide groups allowed for the synthesis of the dialkyl cobalt(II) complex Co(C(SiMe 2 ONaph) 3 ) 2 , where Naph is a naphthyl group. Ab initio calculations on this complex predict a ground state with S = 3 / 2 , L = 3, and J = 9 / 2 arising from the non-Aufbau electron configuration (d x 2 –y 2 , d xy ) 3 (d xz , d yz ) 3 (d z 2 ) 1 . Much as for lanthanide complexes, the ligand field is sufficiently weak that interelectron repulsion and spin-orbit coupling play the key roles in determining the electronic ground state. dc magnetic susceptibility measurements reveal a well-isolated M J = ± 9 / 2 ground state, and simulations of the magnetic data from the calculations are in good agreement with the experimental data. Variable-field far-infrared (FIR) spectroscopy shows a magnetically active excited state at 450 cm −1 that, in combination with calculations and variable-temperature ac magnetic susceptibility experiments, is assigned to the M J = ± 7 / 2 state. Modeling of experimental charge density maps also suggests a d-orbital filling with equally occupied (d x 2 –y 2 , d xy ), and (d xz , d yz ) orbital sets. As a consequence of its large orbital angular momentum, the molecule exhibits slow magnetic relaxation and, in a magnetically dilute sample, a coercive field of 600 Oe at 1.8 K. CONCLUSION Isolation of Co(C(SiMe 2 ONaph) 3 ) 2 illustrates how an extreme coordination environment can confer an f-element–like electronic structure on a transition metal complex. The non-Aufbau ground state enables realization of maximal orbital angular momentum and magnetic anisotropy near the physical limit for a 3d metal. In this respect, the linear L–Co–L motif may prove useful in the design of new materials with high magnetic coercivity.
TL;DR: Current knowledge and underlies mechanisms of anti-inflammatory activities of dietary flavonoids and their influences involved in the development of various inflammatory-related chronic diseases are summarized.
Abstract: Over the past two decades, extensive studies have revealed that inflammation represents a major risk factor for various human diseases. Chronic inflammatory responses predispose to pathological progression of chronic illnesses featured with penetration of inflammatory cells, dysregulation of cellular signaling, excessive generation of cytokines, and loss of barrier function. Hence, the suppression of inflammation has the potential to delay, prevent, and to treat chronic diseases. Flavonoids, which are widely distributed in humans daily diet, such as vegetables, fruits, tea and cocoa, among others, are considered as bioactive compounds with anti-inflammatory potential. Modification of flavonoids including hydroxylation, o-methylation, and glycosylation, can alter their metabolic features and affect mechanisms of inflammation. Structure-activity relationships among naturally occurred flavonoids hence provide us with a preliminary insight into their anti-inflammatory potential, not only attributing to the antioxidant capacity, but also to modulate inflammatory mediators. The present review summarizes current knowledge and underlies mechanisms of anti-inflammatory activities of dietary flavonoids and their influences involved in the development of various inflammatory-related chronic diseases. In addition, the established structure-activity relationships of phenolic compounds in this review may give an insight for the screening of new anti-inflammatory agents from dietary materials.
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: In this article, a low-mass search for resonances decaying into pairs of jets is performed using proton-proton collision data collected at s√=13 TeV corresponding to an integrated luminosity of up to 36 fb−1.
Abstract: Searches for resonances decaying into pairs of jets are performed using proton-proton collision data collected at s√=13 TeV corresponding to an integrated luminosity of up to 36 fb−1. A low-mass search, for resonances with masses between 0.6 and 1.6 TeV, is performed based on events with dijets reconstructed at the trigger level from calorimeter information. A high-mass search, for resonances with masses above 1.6 TeV, is performed using dijets reconstructed offline with a particle-flow algorithm. The dijet mass spectrum is well described by a smooth parameterization and no evidence for the production of new particles is observed. Upper limits at 95% confidence level are reported on the production cross section for narrow resonances with masses above 0.6 TeV. In the context of specific models, the limits exclude string resonances with masses below 7.7 TeV, scalar diquarks below 7.2 TeV, axigluons and colorons below 6.1 TeV, excited quarks below 6.0 TeV, color-octet scalars below 3.4 TeV, W′ bosons below 3.3 TeV, Z′ bosons below 2.7 TeV, Randall-Sundrum gravitons below 1.8 TeV and in the range 1.9 to 2.5 TeV, and dark matter mediators below 2.6 TeV. The limits on both vector and axial-vector mediators, in a simplified model of interactions between quarks and dark matter particles, are presented as functions of dark matter particle mass and coupling to quarks. Searches are also presented for broad resonances, including for the first time spin-1 resonances with intrinsic widths as large as 30% of the resonance mass. The broad resonance search improves and extends the exclusions of a dark matter mediator to larger values of its mass and coupling to quarks.
TL;DR: A statistical combination of several searches for the electroweak production of charginos and neutralinos is presented in this article, where a targeted analysis requiring three or more charged leptons (electrons or muons) is presented, focusing on the challenging scenario in which the difference in mass between the two least massive neutralino is approximately equal to the mass of the Z boson.
Abstract: A statistical combination of several searches for the electroweak production of charginos and neutralinos is presented. All searches use proton-proton collision data at $ \sqrt{s}=13 $ TeV, recorded with the CMS detector at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb$^{−1}$. In addition to the combination of previous searches, a targeted analysis requiring three or more charged leptons (electrons or muons) is presented, focusing on the challenging scenario in which the difference in mass between the two least massive neutralinos is approximately equal to the mass of the Z boson. The results are interpreted in simplified models of chargino-neutralino or neutralino pair production. For chargino-neutralino production, in the case when the lightest neutralino is massless, the combination yields an observed (expected) limit at the 95% confidence level on the chargino mass of up to 650 (570) GeV, improving upon the individual analysis limits by up to 40 GeV. If the mass difference between the two least massive neutralinos is approximately equal to the mass of the Z boson in the chargino-neutralino model, the targeted search requiring three or more leptons obtains observed and expected exclusion limits of around 225 GeV on the second neutralino mass and 125 GeV on the lightest neutralino mass, improving the observed limit by about 60 GeV in both masses compared to the previous CMS result. In the neutralino pair production model, the combined observed (expected) exclusion limit on the neutralino mass extends up to 650–750 (550–750) GeV, depending on the branching fraction assumed. This extends the observed exclusion achieved in the individual analyses by up to 200 GeV. The combined result additionally excludes some intermediate gaps in the mass coverage of the individual analyses.
TL;DR: In this paper, a search for the direct electroweak production of charginos and neutralinos in signatures with either two or more leptons (electrons or muons) of the same electric charge, or with three or more hadronically decaying tau-leptons.
Abstract: Results are presented from a search for the direct electroweak production of charginos and neutralinos in signatures with either two or more leptons (electrons or muons) of the same electric charge, or with three or more leptons, which can include up to two hadronically decaying tau leptons. The results are based on a sample of proton-proton collision data collected at $ \sqrt{s}=13 $ TeV, recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb$^{−1}$. The observed event yields are consistent with the expectations based on the standard model. The results are interpreted in simplified models of supersymmetry describing various scenarios for the production and decay of charginos and neutralinos. Depending on the model parameters chosen, mass values between 180 GeV and 1150 GeV are excluded at 95% CL. These results significantly extend the parameter space probed for these particles in searches at the LHC. In addition, results are presented in a form suitable for alternative theoretical interpretations.
TL;DR: A measurement of the inelastic proton-proton cross section with the CMS detector at a center-of-mass energy of $ \sqrt{s}=13 $ TeV is presented in this paper.
Abstract: A measurement of the inelastic proton-proton cross section with the CMS detector at a center-of-mass energy of $ \sqrt{s}=13 $ TeV is presented. The analysis is based on events with energy deposits in the forward calorimeters, which cover pseudorapidities of −6.6 4.1 GeV and/or M$_{Y}$ > 13 GeV, where M$_{X}$ and M$_{Y}$ are the masses of the diffractive dissociation systems at negative and positive pseudorapidities, respectively. The results are compared with those from other experiments as well as to predictions from high-energy hadron-hadron interaction models.
TL;DR: The first observation of electroweak production of same-sign W boson pairs in proton-proton collisions was reported in this article, where the data sample corresponds to an integrated luminosity of 359 fb^(−1) collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC Events are selected by requiring exactly two leptons (electrons or muons) of the same charge, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass.
Abstract: The first observation of electroweak production of same-sign W boson pairs in proton-proton collisions is reported The data sample corresponds to an integrated luminosity of 359 fb^(−1) collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC Events are selected by requiring exactly two leptons (electrons or muons) of the same charge, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass The observed significance of the signal is 55 standard deviations, where a significance of 57 standard deviations is expected based on the standard model The ratio of measured event yields to that expected from the standard model at leading order is 090 ± 022 A cross section measurement in a fiducial region is reported Bounds are given on the structure of quartic vector boson interactions in the framework of dimension-8 effective field theory operators and on the production of doubly charged Higgs bosons
TL;DR: In this article, a convolutional neural network based open-source pipeline was developed for detecting ultrasonic, full-spectrum, search-phase calls produced by echolocating bats.
Abstract: Passive acoustic sensing has emerged as a powerful tool for quantifying anthropogenic impacts on biodiversity, especially for echolocating bat species. To better assess bat population trends there is a critical need for accurate, reliable, and open source tools that allow the detection and classification of bat calls in large collections of audio recordings. The majority of existing tools are commercial or have focused on the species classification task, neglecting the important problem of first localizing echolocation calls in audio which is particularly problematic in noisy recordings. We developed a convolutional neural network based open-source pipeline for detecting ultrasonic, full-spectrum, search-phase calls produced by echolocating bats. Our deep learning algorithms were trained on full-spectrum ultrasonic audio collected along road-transects across Europe and labelled by citizen scientists from www.batdetective.org. When compared to other existing algorithms and commercial systems, we show significantly higher detection performance of search-phase echolocation calls with our test sets. As an example application, we ran our detection pipeline on bat monitoring data collected over five years from Jersey (UK), and compared results to a widely-used commercial system. Our detection pipeline can be used for the automatic detection and monitoring of bat populations, and further facilitates their use as indicator species on a large scale. Our proposed pipeline makes only a small number of bat specific design decisions, and with appropriate training data it could be applied to detecting other species in audio. A crucial novelty of our work is showing that with careful, non-trivial, design and implementation considerations, state-of-the-art deep learning methods can be used for accurate and efficient monitoring in audio.
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 ...
Albert M. Sirunyan1, Robin Erbacher2, C. A. Carrillo Montoya3, Wagner Carvalho4 +2387 more•Institutions (193)
TL;DR: In this paper, a search for additional neutral Higgs bosons in the τ τ final state in proton-proton collisions at the LHC was performed in the context of the minimal supersymmetric extension of the standard model (MSSM), using the data collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1.
Abstract: A search is presented for additional neutral Higgs bosons in the τ τ final state in proton-proton collisions at the LHC. The search is performed in the context of the minimal supersymmetric extension of the standard model (MSSM), using the data collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. To enhance the sensitivity to neutral MSSM Higgs bosons, the search includes production of the Higgs boson in association with b quarks. No significant deviation above the expected background is observed. Model-independent limits at 95% confidence level (CL) are set on the product of the branching fraction for the decay into τ leptons and the cross section for the production via gluon fusion or in association with b quarks. These limits range from 18 pb at 90 GeV to 3.5 fb at 3.2 TeV for gluon fusion and from 15 pb (at 90 GeV) to 2.5 fb (at 3.2 TeV) for production in association with b quarks, assuming a narrow width resonance. In the m
h
hod +
scenario these limits translate into a 95% CL exclusion of tan β > 6 for neutral Higgs boson masses below 250 GeV, where tan β is the ratio of the vacuum expectation values of the neutral components of the two Higgs doublets. The 95% CL exclusion contour reaches 1.6 TeV for tan β = 60.
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.
TL;DR: In this paper, the authors improved the algorithm developed by the CMS Collaboration to reconstruct and identify τ leptons produced in proton-proton collisions at √s=7 and 8 TeV via their decays to hadrons and a neutrino.
Abstract: The algorithm developed by the CMS Collaboration to reconstruct and identify τ leptons produced in proton-proton collisions at √s=7 and 8 TeV, via their decays to hadrons and a neutrino, has been significantly improved. The changes include a revised reconstruction of π0 candidates, and improvements in multivariate discriminants to separate τ leptons from jets and electrons. The algorithm is extended to reconstruct τ leptons in highly Lorentz-boosted pair production, and in the high-level trigger. The performance of the algorithm is studied using proton-proton collisions recorded during 2016 at √s=13 TeV, corresponding to an integrated luminosity of 35.9 fb-1. The performance is evaluated in terms of the efficiency for a genuine τ lepton to pass the identification criteria and of the probabilities for jets, electrons, and muons to be misidentified as τ leptons. The results are found to be very close to those expected from Monte Carlo simulation.
Albert M. Sirunyan1, Robin Erbacher2, C. A. Carrillo Montoya3, Wagner Carvalho4 +2390 more•Institutions (193)
TL;DR: In this article, a search for new high-mass resonances decaying into electron or muon pairs is presented, where upper limits on the product of a new resonance production cross section and branching fraction to dileptons are calculated in a model-independent manner.
Abstract: A search is presented for new high-mass resonances decaying into electron or muon pairs. The search uses proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the CMS experiment at the LHC in 2016, corresponding to an integrated luminosity of 36 fb$^{−1}$. Observations are in agreement with standard model expectations. Upper limits on the product of a new resonance production cross section and branching fraction to dileptons are calculated in a model-independent manner. This permits the interpretation of the limits in models predicting a narrow dielectron or dimuon resonance. A scan of different intrinsic width hypotheses is performed. Limits are set on the masses of various hypothetical particles. For the $ {Z}_{\mathrm{SSM}}^{\prime}\left({Z}_{{}^{\psi}}^{\prime}\right) $ particle, which arises in the sequential standard model (superstring-inspired model), a lower mass limit of 4.50 (3.90) TeV is set at 95% confidence level. The lightest Kaluza-Klein graviton arising in the Randall-Sundrum model of extra dimensions, with coupling parameters k/M$_{Pl}$ of 0.01, 0.05, and 0.10, is excluded at 95% confidence level below 2.10, 3.65, and 4.25 TeV, respectively. In a simplified model of dark matter production via a vector or axial vector mediator, limits at 95% confidence level are obtained on the masses of the dark matter particle and its mediator.
Environment Agency1, International Union for Conservation of Nature and Natural Resources2, University of Sussex3, Spanish National Research Council4, University of Vienna5, Research Institute for Nature and Forest6, University of Fribourg7, Stellenbosch University8, Newcastle University9, Animal and Plant Health Agency10, European and Mediterranean Plant Protection Organization11, Bournemouth University12, Centre for Environment, Fisheries and Aquaculture Science13, Environmental Protection Agency14, CABI15, Institute for European Environmental Policy16, Indian Ministry of Environment and Forests17, Institute of Technology, Sligo18, University of Bern19, Academy of Sciences of the Czech Republic20, Institut national de la recherche agronomique21, Polish Academy of Sciences22, Bulgarian Academy of Sciences23
TL;DR: In this paper, a review of existing risk assessment protocols, and with reference to the requirements of the EU Regulation on IAS (1143/2014) and international agreements including the World Trade Organisation, Convention on Biological Diversity and International Plant Protection Convention, coupled with consensus methods, identified and agreed upon 14 minimum standards (attributes) a risk assessment scheme should include.
Abstract: 1. Biological invasions are a threat to biodiversity, society and the economy. There is an urgent need to provide evidence-based assessments of the risks posed by inva-sive alien species (IAS) to prioritize action. Risk assessments underpin IAS policies in many ways: informing legislation; providing justification of restrictions in trade or consumer activities; prioritizing surveillance and rapid response. There are benefits to ensuring consistency in content of IAS risk assessments globally, and this can be achieved by providing a framework of minimum standards as a checklist for quality assurance.
2. From a review of existing risk assessment protocols, and with reference to the r equirements of the EU Regulation on IAS (1143/2014) and international agreements including the World Trade Organisation, Convention on Biological Diversity and International Plant Protection Convention, coupled with consensus methods, we identified and agreed upon 14 minimum standards (attributes) a risk-assessment scheme should include.
3. The agreed minimum standards were as follows: (1) basic species description; (2) likelihood of invasion; (3) distribution, spread and impacts; (4) assessment of intro-duction pathways; (5) assessment of impacts on biodiversity and ecosystems; (6) Assessment of impact on ecosystem services; (7) assessment of socio-economic impacts; (8) consideration of status (threatened or protected) of species or habitat under threat; (9) assessment of effects of future climate change; (10) completion possible even when there is a lack of information; (11) documents information sources; (12) provides a summary in a consistent and interpretable form; (13) includes uncertainty; (14) includes quality assurance. In deriving these minimum standards, gaps in knowledge required for completing risk assessments and the scope of exist-ing risk assessment protocols were revealed, most notably in relation to assessing benefits, socio-economic impacts and impacts on ecosystem services but also inclu-sion of consideration of climate change.
4. Policy implications. We provide a checklist of components that should be within in-vasive alien species risk assessments and recommendations to develop risk assess-ments to meet these proposed minimum standards. Although inspired by implementation of the European Union Regulation on invasive alien species, and as such developed specifically within a European context, the derived framework and minimum standards could be applied globally.
TL;DR: In this paper, a search for the production of Higgs boson pairs in proton-proton collisions at a centre-of-mass energy of 13 TeV is presented, using a data sample corresponding to an integrated luminosity of 35.9fb^(−1) collected with the CMS detector at the LHC.
TL;DR: In this article, the axial perturbations of spontaneously scalarized black holes in the Gauss-Bonnet model were studied and the spectrum of the quasinormal modes by time evolution was determined by solving the associated time-independent eigenvalue problem.
Abstract: We study the axial perturbations of spontaneously scalarized black holes in Einstein-Gauss-Bonnet theories. We consider the nodeless solutions of the fundamental branch of the model studied by Doneva and Yazadjiev [Phys. Rev. Lett. 120, 131103 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.131103], which possesses a region of radially stable configurations, as shown by Blazquez-Salcedo et al. [Phys. Rev. D 98, 084011 (2018)PRVDAQ2470-001010.1103/PhysRevD.98.084011]. Here we show that almost all of the radially stable black holes are also stable under axial perturbations. When the axial potential is no longer strictly positive, we make use of the S-deformation method to show stability. As for the radial perturbations, hyperbolicity is lost below a certain critical horizon size for a fixed coupling constant. In the stable region, we determine the spectrum of the quasinormal modes by time evolution and by solving the associated time-independent eigenvalue problem.
TL;DR: In this article, the authors performed searches for resonant and nonresonant pair-produced Higgs bosons (HH) decaying respectively into l nu l nu, through either W or Z bosons, and b (b) over bar.
Abstract: Searches for resonant and nonresonant pair-produced Higgs bosons (HH) decaying respectively into l nu l nu, through either W or Z bosons, and b (b) over bar are presented The analyses are based on a sample of proton-proton collisions at root s = 13 TeV, collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 359 fb(-1) Data and predictions from the standard model are in agreement within uncertainties For the standard model HH hypothesis, the data exclude at 95% confidence level a product of the production cross section and branching fraction larger than 72 fb, corresponding to 79 times the standard model prediction Constraints are placed on different scenarios considering anomalous couplings, which could affect the rate and kinematics of HH production Upper limits at 95% confidence level are set on the production cross section of narrow-width spin-0 and spin-2 particles decaying to Higgs boson pairs, the latter produced with minimal gravity-like coupling