ORCID Profile
0000-0002-6743-7122
Current Organisation
KU Leuven
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 26-04-2022
Abstract: The top quark pair production cross section is measured in proton-proton collisions at a center-of-mass energy of 5.02 TeV. The data were collected in a special LHC low-energy and low-intensity run in 2017, and correspond to an integrated luminosity of 302 pb − 1 . The measurement is performed using events with one electron and one muon of opposite charge, and at least two jets. The measured cross section is 60 . 7 ± 5 . 0 (stat) ± 2 . 8 (syst) ± 1 . 1 (lumi) pb. A combination with the result in the single lepton + jets channel, based on data collected in 2015 at the same center-of-mass energy and corresponding to an integrated luminosity of 27.4 pb − 1 , is then performed. The resulting measured value is 63 . 0 ± 4 . 1 (stat) ± 3 . 0 (syst+lumi) pb, in agreement with the standard model prediction of $$ {66.8}_{-3.1}^{+2.9} $$ 66.8 − 3.1 + 2.9 pb.
Publisher: Elsevier BV
Date: 03-2020
Publisher: American Physical Society (APS)
Date: 26-04-2022
Publisher: American Geophysical Union (AGU)
Date: 09-2007
DOI: 10.1029/2006WR005449
Publisher: Springer Science and Business Media LLC
Date: 11-04-2022
Abstract: A search for long-lived particles decaying into muon pairs is performed using proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment at the LHC in 2017 and 2018, corresponding to an integrated luminosity of 101 fb − 1 . The data sets used in this search were collected with a dedicated dimuon trigger stream with low transverse momentum thresholds, recorded at high rate by retaining a reduced amount of information, in order to explore otherwise inaccessible phase space at low dimuon mass and nonzero displacement from the primary interaction vertex. No significant excess of events beyond the standard model expectation is found. Upper limits on branching fractions at 95% confidence level are set on a wide range of mass and lifetime hypotheses in beyond the standard model frameworks with the Higgs boson decaying into a pair of long-lived dark photons, or with a long-lived scalar resonance arising from a decay of a b hadron. The limits are the most stringent to date for substantial regions of the parameter space. These results can be also used to constrain models of displaced dimuons that are not explicitly considered in this paper.
Publisher: American Geophysical Union (AGU)
Date: 2012
DOI: 10.1029/2011WR010588
Publisher: Springer Science and Business Media LLC
Date: 07-2022
Abstract: A search for physics beyond the standard model (SM) in final states with an electron or muon and missing transverse momentum is presented. The analysis uses data from proton-proton collisions at a centre-of-mass energy of 13 TeV, collected with the CMS detector at the LHC in 2016–2018 and corresponding to an integrated luminosity of 138 fb − 1 . No significant deviation from the SM prediction is observed. Model-independent limits are set on the production cross section of W’ bosons decaying into lepton-plus-neutrino final states. Within the framework of the sequential standard model, with the combined results from the electron and muon decay channels a W’ boson with mass less than 5.7 TeV is excluded at 95% confidence level. Results on a SM precision test, the determination of the oblique electroweak W parameter, are presented using LHC data for the first time. These results together with those from the direct W’ resonance search are used to extend existing constraints on composite Higgs scenarios. This is the first experimental exclusion on compositeness parameters using results from LHC data other than Higgs boson measurements.
Publisher: Copernicus GmbH
Date: 13-09-2013
DOI: 10.5194/HESS-17-3499-2013
Abstract: Abstract. In this paper, we present a two-stage hybrid Kalman filter to estimate both observation and forecast bias in hydrologic models, in addition to state variables. The biases are estimated using the discrete Kalman filter, and the state variables using the ensemble Kalman filter. A key issue in this multi-component assimilation scheme is the exact partitioning of the difference between observation and forecasts into state, forecast bias and observation bias updates. Here, the error covariances of the forecast bias and the unbiased states are calculated as constant fractions of the biased state error covariance, and the observation bias error covariance is a function of the observation prediction error covariance. In a series of synthetic experiments, focusing on the assimilation of discharge into a rainfall-runoff model, it is shown that both static and dynamic observation and forecast biases can be successfully estimated. The results indicate a strong improvement in the estimation of the state variables and resulting discharge as opposed to the use of a bias-unaware ensemble Kalman filter. Furthermore, minimal code modification in existing data assimilation software is needed to implement the method. The results suggest that a better performance of data assimilation methods should be possible if both forecast and observation biases are taken into account.
Publisher: IOP Publishing
Date: 07-2022
DOI: 10.1088/1748-0221/17/07/P07023
Abstract: A new algorithm is presented to discriminate reconstructed hadronic decays of tau leptons ( τ h ) that originate from genuine tau leptons in the CMS detector against τ h candidates that originate from quark or gluon jets, electrons, or muons. The algorithm inputs information from all reconstructed particles in the vicinity of a τ h candidate and employs a deep neural network with convolutional layers to efficiently process the inputs. This algorithm leads to a significantly improved performance compared with the previously used one. For ex le, the efficiency for a genuine τ h to pass the discriminator against jets increases by 10–30% for a given efficiency for quark and gluon jets. Furthermore, a more efficient τ h reconstruction is introduced that incorporates additional hadronic decay modes. The superior performance of the new algorithm to discriminate against jets, electrons, and muons and the improved τ h reconstruction method are validated with LHC proton-proton collision data at √ s = 13 TeV.
Publisher: Elsevier BV
Date: 11-2022
Publisher: Springer Science and Business Media LLC
Date: 13-09-2022
Abstract: A search is presented for a heavy W′ boson resonance decaying to a B or T vector-like quark and a t or a b quark, respectively. The analysis is performed using proton-proton collisions collected with the CMS detector at the LHC. The data correspond to an integrated luminosity of 138 fb − 1 at a center-of-mass energy of 13 TeV. Both decay channels result in a signature with a t quark, a Higgs or Z boson, and a b quark, each produced with a significant Lorentz boost. The all-hadronic decays of the Higgs or Z boson and of the t quark are selected using jet substructure techniques to reduce standard model backgrounds, resulting in a distinct three-jet W′ boson decay signature. No significant deviation in data with respect to the standard model background prediction is observed. Upper limits are set at 95% confidence level on the product of the W′ boson cross section and the final state branching fraction. A W′ boson with a mass below 3.1 TeV is excluded, given the benchmark model assumption of democratic branching fractions. In addition, limits are set based on generalizations of these assumptions. These are the most sensitive limits to date for this final state.
Publisher: American Physical Society (APS)
Date: 09-03-2022
Publisher: American Geophysical Union (AGU)
Date: 08-2009
DOI: 10.1029/2008WR007590
Publisher: American Physical Society (APS)
Date: 20-05-2022
Publisher: American Meteorological Society
Date: 06-2009
Abstract: Data assimilation aims to provide an optimal estimate of the overall system state, not only for an observed state variable or location. However, large-scale land surface models are typically column-based and purely random ensemble perturbation of states will lead to block-diagonal a priori (or background) error covariance. This facilitates the filtering calculations but compromises the potential of data assimilation to influence (unobserved) vertical and horizontal neighboring state variables. Here, a combination of an ensemble Kalman filter and an adaptive covariance correction method is explored to optimize the variances and retrieve the off-block-diagonal correlations in the a priori error covariance matrix. In a first time period, all available soil moisture profile observations in a small agricultural field are assimilated into the Community Land Model, version 2.0 (CLM2.0) to find the adaptive second-order a priori error information. After that period, only observations from single in idual soil profiles are assimilated with inclusion of this adaptive information. It is shown that assimilation of a single profile can partially rectify the incorrectly simulated soil moisture spatial mean and variability. The largest reduction in the root-mean-square error in the soil moisture field varies between 7% and 22%, depending on the soil depth, when assimilating a single complete profile every two days during three months with a single time-invariant covariance correction.
Publisher: Springer Science and Business Media LLC
Date: 03-2022
Abstract: A search for long-lived particles (LLPs) produced in association with a Z boson is presented. The study is performed using data from proton-proton collisions with a center-of-mass energy of 13 TeV recorded by the CMS experiment during 2016–2018, corresponding to an integrated luminosity of 117 fb − 1 . The LLPs are assumed to decay to a pair of standard model quarks that are identified as displaced jets within the CMS tracker system. Triggers and selections based on Z boson decays to electron or muon pairs improve the sensitivity to light LLPs (down to 15 GeV). This search provides sensitivity to beyond the standard model scenarios which predict LLPs produced in association with a Z boson. In particular, the results are interpreted in the context of exotic decays of the Higgs boson to a pair of scalar LLPs (H → SS). The Higgs boson decay branching fraction is constrained to values less than 6% for proper decay lengths of 10–100 mm and for LLP masses between 40 and 55 GeV. In the case of low-mass ( ≈ 15 GeV) scalar particles that subsequently decay to a pair of b quarks, the search is sensitive to branching fractions $$ \\mathcal{B} $$ B (H → SS) 20% for proper decay lengths of 10–50 mm. The use of associated production with a Z boson increases the sensitivity to low-mass LLPs of this analysis with respect to gluon fusion searches. In the case of 15 GeV scalar LLPs, the improvement corresponds to a factor of 2 at a proper decay length of 30 mm.
Publisher: American Geophysical Union (AGU)
Date: 03-2011
DOI: 10.1029/2010WR009204
Publisher: American Geophysical Union (AGU)
Date: 04-2007
DOI: 10.1029/2006WR004942
Publisher: Springer Science and Business Media LLC
Date: 02-2022
Abstract: Inclusive and differential cross sections of single top quark production in association with a Z boson are measured in proton-proton collisions at a center-of-mass energy of 13 TeV with a data s le corresponding to an integrated luminosity of 138 fb − 1 recorded by the CMS experiment. Events are selected based on the presence of three leptons, electrons or muons, associated with leptonic Z boson and top quark decays. The measurement yields an inclusive cross section of $$ {87.9}_{-7.3}^{+7.5}{\\left(\\mathrm{stat}\\right)}_{-6.0}^{+7.3}\\left(\\mathrm{syst}\\right) $$ 87.9 − 7.3 + 7.5 stat − 6.0 + 7.3 syst fb for a dilepton invariant mass greater than 30 GeV, in agreement with standard model (SM) calculations and represents the most precise determination to date. The ratio between the cross sections for the top quark and the top antiquark production in association with a Z boson is measured as $$ {2.37}_{-0.42}^{+0.56}{\\left(\\mathrm{stat}\\right)}_{-0.13}^{+0.27}\\left(\\mathrm{syst}\\right) $$ 2.37 − 0.42 + 0.56 stat − 0.13 + 0.27 syst . Differential measurements at parton and particle levels are performed for the first time. Several kinematic observables are considered to study the modeling of the process. Results are compared to theoretical predictions with different assumptions on the source of the initial-state b quark and found to be in agreement, within the uncertainties. Additionally, the spin asymmetry, which is sensitive to the top quark polarization, is determined from the differential distribution of the polarization angle at parton level to be 0 . 54 ± 0 . 16 (stat) ± 0 . 06 (syst), in agreement with SM predictions.
Publisher: American Physical Society (APS)
Date: 05-07-2022
Publisher: Springer Science and Business Media LLC
Date: 02-05-2012
Abstract: A search for new heavy resonances decaying to a pair of Higgs bosons (HH) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented. Data were collected with the CMS detector at the LHC in 2016–2018, corresponding to an integrated luminosity of 138 fb − 1 . Resonances with a mass between 0.8 and 4.5 TeV are considered using events in which one Higgs boson decays into a bottom quark pair and the other into final states with either one or two charged leptons. Specifically, the single-lepton decay channel $$ \\mathrm{HH}\\to \\mathrm{b}\\overline{\\mathrm{b}}{\\mathrm{WW}}^{\\ast}\\to \\mathrm{b}\\overline{\\mathrm{b}}\\ell v\\mathrm{q}{\\overline{\\mathrm{q}}}^{\\prime } $$ HH → b b ¯ WW ∗ → b b ¯ ℓ v q q ¯ ′ and the dilepton decay channels $$ \\mathrm{HH}\\to \\mathrm{b}\\overline{\\mathrm{b}}{\\mathrm{WW}}^{\\ast}\\to \\mathrm{b}\\overline{\\mathrm{b}}\\ell v\\ell v $$ HH → b b ¯ WW ∗ → b b ¯ ℓ v ℓ v and $$ \\mathrm{HH}\\to \\mathrm{b}\\overline{\\mathrm{b}}\\uptau \\uptau \\to \\mathrm{b}\\overline{\\mathrm{b}}\\ell vv\\ell vv $$ HH → b b ¯ ττ → b b ¯ ℓ vv ℓ vv are examined, where ℓ in the final state corresponds to an electron or muon. The signal is extracted using a two-dimensional maximum likelihood fit of the $$ \\mathrm{H}\\to \\mathrm{b}\\overline{\\mathrm{b}} $$ H → b b ¯ jet mass and HH invariant mass distributions. No significant excess above the standard model expectation is observed in data. Model-independent exclusion limits are placed on the product of the cross section and branching fraction for narrow spin-0 and spin-2 massive bosons decaying to HH. The results are also interpreted in the context of radion and bulk graviton production in models with a warped extra spatial dimension. The results provide the most stringent limits to date for X → HH signatures with final-state leptons and at some masses provide the most sensitive limits of all X → HH searches.
Publisher: SPIE
Date: 06-10-2005
DOI: 10.1117/12.627075
Publisher: Elsevier BV
Date: 07-2021
Publisher: IOP Publishing
Date: 03-2022
DOI: 10.1088/1748-0221/17/03/P03014
Abstract: Many measurements at the LHC require efficient identification of heavy-flavour jets, i.e. jets originating from bottom (b) or charm (c) quarks. An overview of the algorithms used to identify c jets is described and a novel method to calibrate them is presented. This new method adjusts the entire distributions of the outputs obtained when the algorithms are applied to jets of different flavours. It is based on an iterative approach exploiting three distinct control regions that are enriched with either b jets, c jets, or light-flavour and gluon jets. Results are presented in the form of correction factors evaluated using proton-proton collision data with an integrated luminosity of 41.5 fb -1 at √s = 13 TeV, collected by the CMS experiment in 2017. The closure of the method is tested by applying the measured correction factors on simulated data sets and checking the agreement between the adjusted simulation and collision data. Furthermore, a validation is performed by testing the method on pseudodata, which emulate various mismodelling conditions. The calibrated results enable the use of the full distributions of heavy-flavour identification algorithm outputs, e.g. as inputs to machine-learning models. Thus, they are expected to increase the sensitivity of future physics analyses.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Springer Science and Business Media LLC
Date: 16-05-2022
Abstract: A search is presented for single production of a vector-like T quark with charge 2 / 3 e , in the decay channel featuring a top quark and a Z boson, with the top quark decaying hadronically and the Z boson decaying to neutrinos. The search uses data collected by the CMS experiment in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb − 1 recorded at the CERN LHC in 2016–2018. The search is sensitive to a T quark mass between 0.6 and 1.8 TeV with decay widths ranging from negligibly small up to 30% of the T quark mass. Reconstruction strategies for the top quark are based on the degree of Lorentz boosting of its final state. At 95% confidence level, the upper limit on the product of the cross section and branching fraction for a T quark of small decay width varies between 15 and 602 fb, depending on its mass. For a T quark with decay widths between 10 and 30% of its mass, this upper limit ranges between 16 and 836 fb. For most of the studied range, the results provide the best limits to date. This is the first search for single T quark production based on the full Run 2 data set of the LHC.
Publisher: Elsevier BV
Date: 08-2022
Publisher: American Geophysical Union (AGU)
Date: 07-2013
DOI: 10.1002/WRCR.20291
Publisher: Springer Science and Business Media LLC
Date: 16-05-2022
Abstract: The production cross section of a top quark pair in association with a photon is measured in proton-proton collisions in the decay channel with two oppositely charged leptons ( e ± μ ∓ , e + e − , or μ + μ − ). The measurement is performed using 138 fb − 1 of proton-proton collision data recorded by the CMS experiment at $$ \\sqrt{s} $$ s = 13 TeV during the 2016–2018 data-taking period of the CERN LHC. A fiducial phase space is defined such that photons radiated by initial-state particles, top quarks, or any of their decay products are included. An inclusive cross section of 175 . 2 ± 2 . 5(stat) ± 6 . 3(syst) fb is measured in a signal region with at least one jet coming from the hadronization of a bottom quark and exactly one photon with transverse momentum above 20 GeV. Differential cross sections are measured as functions of several kinematic observables of the photon, leptons, and jets, and compared to standard model predictions. The measurements are also interpreted in the standard model effective field theory framework, and limits are found on the relevant Wilson coefficients from these results alone and in combination with a previous CMS measurement of the t $$ \\overline{t} $$ t ¯ γ production process using the lepton+jets final state.
Publisher: American Meteorological Society
Date: 06-2013
Abstract: A zero-order (tau-omega) microwave radiative transfer model (RTM) is coupled to the Goddard Earth Observing System, version 5 (GEOS-5) catchment land surface model in preparation for the future assimilation of global brightness temperatures (Tb) from the L-band (1.4 GHz) Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) missions. Simulations using literature values for the RTM parameters result in Tb biases of 10–50 K against SMOS observations. Multiangular SMOS observations during nonfrozen conditions from 1 July 2011 to 1 July 2012 are used to calibrate parameters related to the microwave roughness h, vegetation opacity τ and/or scattering albedo ω separately for each observed 36-km land grid cell. A particle swarm optimization is used to minimize differences in the long-term (climatological) mean values and standard deviations between SMOS observations and simulations, without attempting to reduce the shorter-term (seasonal to daily) errors. After calibration, global Tb simulations for the validation year (1 July 2010 to 1 July 2011) are largely unbiased for multiple incidence angles and both H and V polarization [e.g., the global average absolute difference is 2.7 K for TbH(42.5°), i.e., at 42.5° incidence angle]. The calibrated parameter values depend to some extent on the specific land surface conditions simulated by the GEOS-5 system and on the scale of the SMOS observations, but they also show realistic spatial distributions. Aggregating the calibrated parameter values by vegetation class prior to using them in the RTM maintains low global biases but increases local biases [e.g., the global average absolute difference is 7.1 K for TbH(42.5°)].
Publisher: Springer Science and Business Media LLC
Date: 20-10-2022
DOI: 10.1038/S41567-022-01682-0
Abstract: Since the discovery of the Higgs boson in 2012, detailed studies of its properties have been ongoing. Besides its mass, its width—related to its lifetime—is an important parameter. One way to determine this quantity is to measure its off-shell production, where the Higgs boson mass is far away from its nominal value, and relating it to its on-shell production, where the mass is close to the nominal value. Here we report evidence for such off-shell contributions to the production cross-section of two Z bosons with data from the CMS experiment at the CERN Large Hadron Collider. We constrain the total rate of the off-shell Higgs boson contribution beyond the Z boson pair production threshold, relative to its standard model expectation, to the interval [0.0061, 2.0] at the 95% confidence level. The scenario with no off-shell contribution is excluded at a p -value of 0.0003 (3.6 standard deviations). We measure the width of the Higgs boson as $${{{\\varGamma }}}_{{{{{{\\rm{H}}}}}}}={3.2}_{-1.7}^{+2.4}\\,{{{{{\\rm{MeV}}}}}}$$ Γ H = 3.2 − 1.7 + 2.4 MeV , in agreement with the standard model expectation of 4.1 MeV. In addition, we set constraints on anomalous Higgs boson couplings to W and Z boson pairs.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Springer Science and Business Media LLC
Date: 19-01-2023
DOI: 10.1038/S41567-022-01838-Y
Abstract: Protons consist of three valence quarks, two up-quarks and one down-quark, held together by gluons and a sea of quark-antiquark pairs. Collectively, quarks and gluons are referred to as partons. In a proton-proton collision, typically only one parton of each proton undergoes a hard scattering – referred to as single-parton scattering – leaving the remainder of each proton only slightly disturbed. Here, we report the study of double- and triple-parton scatterings through the simultaneous production of three J/ ψ mesons, which consist of a charm quark-antiquark pair, in proton-proton collisions recorded with the CMS experiment at the Large Hadron Collider. We observed this process – reconstructed through the decays of J/ ψ mesons into pairs of oppositely charged muons – with a statistical significance above five standard deviations. We measured the inclusive fiducial cross-section to be $$27{2}_{-104}^{+141}\\,{{{\\rm{(stat)}}}}\\,\\pm 17\\,{{{\\rm{(syst)}}}}\\,{{{\\rm{fb}}}}\\,$$ 27 2 − 104 + 141 (stat) ± 17 (syst) fb , and compared it to theoretical expectations for triple-J/ ψ meson production in single-, double- and triple-parton scattering scenarios. Assuming factorization of multiple hard-scattering probabilities in terms of single-parton scattering cross-sections, double- and triple-parton scattering are the dominant contributions for the measured process.
Publisher: Springer Science and Business Media LLC
Date: 05-2022
DOI: 10.1140/EPJC/S10052-022-10315-Y
Abstract: Using a data s le of $$\\sqrt{s}=13\\,\\text {TeV}$$ s = 13 TeV proton-proton collisions collected by the CMS experiment at the LHC in 2017 and 2018 with an integrated luminosity of $$103\\text {~fb}^{-1}$$ 103 fb - 1 , the $$\\text {B}^{0}_{\\mathrm{s}} \\rightarrow \\uppsi (\\text {2S})\\text {K}_\\mathrm{S}^{0}$$ B s 0 → ψ ( 2S ) K S 0 and $$\\text {B}^{0} \\rightarrow \\uppsi (\\text {2S})\\text {K}_\\mathrm{S}^{0} \\uppi ^+\\uppi ^-$$ B 0 → ψ ( 2S ) K S 0 π + π - decays are observed with significances exceeding 5 standard deviations. The resulting branching fraction ratios, measured for the first time, correspond to $${\\mathcal {B}}(\\text {B}^{0}_{\\mathrm{s}} \\rightarrow \\uppsi (\\text {2S})K_\\mathrm{S}^{0})/{\\mathcal {B}}(\\text {B}^{0}\\rightarrow \\uppsi (\\text {2S})K_\\mathrm{S}^{0}) = (3.33 \\pm 0.69 (\\text {stat})\\, \\pm 0.11\\,(\\text {syst}) \\pm 0.34\\,(f_{\\mathrm{s}}/f_{\\mathrm{d}})) \\times 10^{-2}$$ B ( B s 0 → ψ ( 2S ) K S 0 ) / B ( B 0 → ψ ( 2S ) K S 0 ) = ( 3.33 ± 0.69 ( stat ) ± 0.11 ( syst ) ± 0.34 ( f s / f d ) ) × 10 - 2 and $${\\mathcal {B}}(\\text {B}^{0} \\rightarrow \\uppsi (\\text {2S})\\text {K}_\\mathrm{S}^{0} \\uppi ^{+} \\uppi ^{-})/ {\\mathcal {B}}(\\text {B}^{0} \\rightarrow \\uppsi (\\text {2S})\\text {K}^{0}_{\\mathrm{S}}) = 0.480 \\pm 0.013\\,(\\text {stat}) \\pm 0.032\\,(\\text {syst})$$ B ( B 0 → ψ ( 2S ) K S 0 π + π - ) / B ( B 0 → ψ ( 2S ) K S 0 ) = 0.480 ± 0.013 ( stat ) ± 0.032 ( syst ) , where the last uncertainty in the first ratio is related to the uncertainty in the ratio of production cross sections of $$\\hbox {B}^{0}_{\\mathrm{s}}$$ B s 0 and $$\\hbox {B}^{0}$$ B 0 mesons, $$f_{\\mathrm{s}}/f_{\\mathrm{d}}$$ f s / f d .
Publisher: American Physical Society (APS)
Date: 14-06-2022
Publisher: American Geophysical Union (AGU)
Date: 18-08-2021
DOI: 10.1029/2020RG000715
Abstract: A reanalysis is a physically consistent set of optimally merged simulated model states and historical observational data, using data assimilation. High computational costs for modeled processes and assimilation algorithms has led to Earth system specific reanalysis products for the atmosphere, the ocean and the land separately. Recent developments include the advanced uncertainty quantification and the generation of biogeochemical reanalysis for land and ocean. Here, we review atmospheric and oceanic reanalyzes, and more in detail biogeochemical ocean and terrestrial reanalyzes. In particular, we identify land surface, hydrologic and carbon cycle reanalyzes which are nowadays produced in targeted projects for very specific purposes. Although a future joint reanalysis of land surface, hydrologic, and carbon processes represents an analysis of important ecosystem variables, biotic ecosystem variables are assimilated only to a very limited extent. Continuous data sets of ecosystem variables are needed to explore biotic‐abiotic interactions and the response of ecosystems to global change. Based on the review of existing achievements, we identify five major steps required to develop terrestrial ecosystem reanalysis to deliver continuous data streams on ecosystem dynamics.
Publisher: American Geophysical Union (AGU)
Date: 06-05-2017
DOI: 10.1002/2017GL072994
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2022
Publisher: American Meteorological Society
Date: 28-09-2017
Abstract: The Soil Moisture Active Passive (SMAP) mission Level-4 Surface and Root-Zone Soil Moisture (L4_SM) data product is generated by assimilating SMAP L-band brightness temperature observations into the NASA Catchment land surface model. The L4_SM product is available from 31 March 2015 to present (within 3 days from real time) and provides 3-hourly, global, 9-km resolution estimates of surface (0–5 cm) and root-zone (0–100 cm) soil moisture and land surface conditions. This study presents an overview of the L4_SM algorithm, validation approach, and product assessment versus in situ measurements. Core validation sites provide spatially averaged surface (root zone) soil moisture measurements for 43 (17) “reference pixels” at 9- and 36-km gridcell scales located in 17 (7) distinct watersheds. Sparse networks provide point-scale measurements of surface (root zone) soil moisture at 406 (311) locations. Core validation site results indicate that the L4_SM product meets its soil moisture accuracy requirement, specified as an unbiased RMSE (ubRMSE, or standard deviation of the error) of 0.04 m3 m−3 or better. The ubRMSE for L4_SM surface (root zone) soil moisture is 0.038 m3 m−3 (0.030 m3 m−3) at the 9-km scale and 0.035 m3 m−3 (0.026 m3 m−3) at the 36-km scale. The L4_SM estimates improve (significantly at the 5% level for surface soil moisture) over model-only estimates, which do not benefit from the assimilation of SMAP brightness temperature observations and have a 9-km surface (root zone) ubRMSE of 0.042 m3 m−3 (0.032 m3 m−3). Time series correlations exhibit similar relative performance. The sparse network results corroborate these findings over a greater variety of climate and land cover conditions.
Publisher: Springer Science and Business Media LLC
Date: 14-04-2022
Abstract: A search has been performed for heavy resonances decaying to ZZ or ZW and for axion-like particles (ALPs) mediating nonresonant ZZ or ZH production, in final states with two charged leptons ( ℓ = e , μ) produced by the decay of a Z boson, and two quarks produced by the decay of a Z, W, or Higgs boson H. The analysis is sensitive to resonances with masses in the range 450 to 2000 GeV. Two categories are defined corresponding to the merged or resolved reconstruction of the hadronically decaying boson. The search is based on data collected during 2016–2018 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb − 1 . No significant excess is observed in the data above the standard model background expectation. Upper limits on the production cross section of heavy, narrow spin-2 and spin-1 resonances are derived as functions of the resonance mass, and exclusion limits on the production of bulk graviton particles and W′ bosons are calculated in the framework of the warped extra dimensions and heavy vector triplet models, respectively. In addition, upper limits on the ALP-mediated diboson production cross section and ALP couplings to standard model particles are obtained in the framework of linear and chiral effective field theories. These are the first limits on nonresonant ALP-mediated ZZ and ZH production obtained by the LHC experiments.
Publisher: Elsevier BV
Date: 07-2016
Publisher: American Geophysical Union (AGU)
Date: 17-05-2006
DOI: 10.1029/2005JD006367
Publisher: Elsevier BV
Date: 09-2007
Publisher: Springer Science and Business Media LLC
Date: 03-05-2022
Abstract: Results are presented from a search for physics beyond the standard model in proton-proton collisions at $$ \\sqrt{s} $$ s = 13 TeV in channels with two Higgs bosons, each decaying via the process H → b $$ \\overline{\\mathrm{b}} $$ b ¯ , and large missing transverse momentum. The search uses a data s le corresponding to an integrated luminosity of 137 fb − 1 collected by the CMS experiment at the CERN LHC. The search is motivated by models of supersymmetry that predict the production of neutralinos, the neutral partners of the electroweak gauge and Higgs bosons. The observed event yields in the signal regions are found to be consistent with the standard model background expectations. The results are interpreted using simplified models of supersymmetry. For the electroweak production of nearly mass-degenerate higgsinos, each of whose decay chains yields a neutralino $$ \\left({\\overset{\\sim }{\\upchi}}_1^0\\right) $$ χ ~ 1 0 that in turn decays to a massless goldstino and a Higgs boson, $$ \\left({\\overset{\\sim }{\\upchi}}_1^0\\right) $$ χ ~ 1 0 masses in the range 175 to 1025 GeV are excluded at 95% confidence level. For the strong production of gluino pairs decaying via a slightly lighter $$ \\left({\\overset{\\sim }{\\upchi}}_2^0\\right) $$ χ ~ 2 0 to H and a light $$ \\left({\\overset{\\sim }{\\upchi}}_1^0\\right) $$ χ ~ 1 0 , gluino masses below 2330 GeV are excluded.
Publisher: American Physical Society (APS)
Date: 18-08-2022
Publisher: American Geophysical Union (AGU)
Date: 06-2007
DOI: 10.1029/2006WR005100
Publisher: Springer Science and Business Media LLC
Date: 08-04-2022
Abstract: A search for a heavy resonance decaying into a top quark and a W boson in proton-proton collisions at $$ \\sqrt{s} $$ s = 13 TeV is presented. The data analyzed were recorded with the CMS detector at the LHC and correspond to an integrated luminosity of 138 fb − 1 . The top quark is reconstructed as a single jet and the W boson, from its decay into an electron or muon and the corresponding neutrino. A top quark tagging technique based on jet clustering with a variable distance parameter and simultaneous jet grooming is used to identify jets from the collimated top quark decay. The results are interpreted in the context of two benchmark models, where the heavy resonance is either an excited bottom quark b ∗ or a vector-like quark B. A statistical combination with an earlier search by the CMS Collaboration in the all-hadronic final state is performed to place upper cross section limits on these two models. The new analysis extends the lower range of resonance mass probed from 1.4 down to 0.7 TeV. For left-handed, right-handed, and vector-like couplings, b ∗ masses up to 3.0, 3.0, and 3.2 TeV are excluded at 95% confidence level, respectively. The observed upper limits represent the most stringent constraints on the b ∗ model to date.
Publisher: Copernicus GmbH
Date: 27-09-2010
DOI: 10.5194/HESS-14-1773-2010
Abstract: Abstract. With the onset of new satellite radar constellations (e.g. Sentinel-1) and advances in computational science (e.g. grid computing) enabling the supply and processing of multi-mission satellite data at a temporal frequency that is compatible with real-time flood forecasting requirements, this study presents a new concept for the sequential assimilation of Synthetic Aperture Radar (SAR)-derived water stages into coupled hydrologic-hydraulic models. The proposed methodology consists of adjusting storages and fluxes simulated by a coupled hydrologic-hydraulic model using a Particle Filter-based data assimilation scheme. Synthetic observations of water levels, representing satellite measurements, are assimilated into the coupled model in order to investigate the performance of the proposed assimilation scheme as a function of both accuracy and frequency of water level observations. The use of the Particle Filter provides flexibility regarding the form of the probability densities of both model simulations and remote sensing observations. We illustrate the potential of the proposed methodology using a twin experiment over a widely studied river reach located in the Grand-Duchy of Luxembourg. The study demonstrates that the Particle Filter algorithm leads to significant uncertainty reduction of water level and discharge at the time step of assimilation. However, updating the storages of the model only improves the model forecast over a very short time horizon. A more effective way of updating thus consists in adjusting both states and inputs. The proposed methodology, which consists in updating the biased forcing of the hydraulic model using information on model errors that is inferred from satellite observations, enables persistent model improvement. The present schedule of satellite radar missions is such that it is likely that there will be continuity for SAR-based operational water management services. This research contributes to evolve reactive flood management into systematic or quasi-systematic SAR-based flood monitoring services.
Publisher: Springer Science and Business Media LLC
Date: 08-04-2022
Abstract: A search is presented for a right-handed W boson (W R ) and a heavy neutrino (N), in a final state consisting of two same-flavor leptons (ee or μμ) and two quarks. The search is performed with the CMS experiment at the CERN LHC using a data s le of proton-proton collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138 fb − 1 . The search covers two regions of phase space, one where the decay products of the heavy neutrino are merged into a single large-area jet, and one where the decay products are well separated. The expected signal is characterized by an excess in the invariant mass distribution of the final-state objects. No significant excess over the standard model background expectations is observed. The observations are interpreted as upper limits on the product of W R production cross sections and branching fractions assuming that couplings are identical to those of the standard model W boson. For N masses m N equal to half the W R mass $$ {m}_{{\\mathrm{W}}_{\\mathrm{R}}} $$ m W R ( m N = 0 . 2 TeV), $$ {m}_{{\\mathrm{W}}_{\\mathrm{R}}} $$ m W R is excluded at 95% confidence level up to 4.7 (4.8) and 5.0 (5.4) TeV for the electron and muon channels, respectively. This analysis provides the most stringent limits on the W R mass to date.
Publisher: Springer Science and Business Media LLC
Date: 04-08-2022
Abstract: A measurement of the forward-backward asymmetry of pairs of oppositely charged leptons (dimuons and dielectrons) produced by the Drell-Yan process in proton-proton collisions is presented. The data s le corresponds to an integrated luminosity of 138 fb − 1 collected with the CMS detector at the LHC at a center-of-mass energy of 13 TeV. The asymmetry is measured as a function of lepton pair mass for masses larger than 170 GeV and compared with standard model predictions. An inclusive measurement across both channels and the full mass range yields an asymmetry of 0 . 612 ± 0 . 005 (stat) ± 0 . 007 (syst). As a test of lepton flavor universality, the difference between the dimuon and dielectron asymmetries is measured as well. No statistically significant deviations from standard model predictions are observed. The measurements are used to set limits on the presence of additional gauge bosons. For a Z′ boson in the sequential standard model the observed (expected) 95% confidence level lower limit on the Z′ mass is 4.4 TeV (3.7 TeV).
Publisher: American Physical Society (APS)
Date: 21-06-2022
Publisher: American Meteorological Society
Date: 04-2010
Abstract: Four methods based on the ensemble Kalman filter (EnKF) are tested to assimilate coarse-scale (25 km) snow water equivalent (SWE) observations (typical of passive microwave satellite retrievals) into finescale (1 km) land model simulations. Synthetic coarse-scale observations are assimilated directly using an observation operator for mapping between the coarse and fine scales or, alternatively, after disaggregation (regridding) to the finescale model resolution prior to data assimilation. In either case, observations are assimilated either simultaneously or independently for each location. Results indicate that assimilating disaggregated finescale observations independently (method 1D-F1) is less efficient than assimilating a collection of neighboring disaggregated observations (method 3D-Fm). Direct assimilation of coarse-scale observations is superior to a priori disaggregation. Independent assimilation of in idual coarse-scale observations (method 3D-C1) can bring the overall mean analyzed field close to the truth, but does not necessarily improve estimates of the finescale structure. There is a clear benefit to simultaneously assimilating multiple coarse-scale observations (method 3D-Cm) even as the entire domain is observed, indicating that underlying spatial error correlations can be exploited to improve SWE estimates. Method 3D-Cm avoids artificial transitions at the coarse observation pixel boundaries and can reduce the RMSE by 60% when compared to the open loop in this study.
Publisher: Springer Science and Business Media LLC
Date: 03-2022
Abstract: The cross sections for inclusive and Mueller-Navelet dijet production are measured as a function of the rapidity separation between the jets in proton-proton collisions at $$ \sqrt{s} $$ s = 2 . 76 TeV for jets with transverse momentum p T 35 GeV and rapidity | y | 4 . 7. Various dijet production cross section ratios are also measured. A veto on additional jets with p T 20 GeV is introduced to improve the sensitivity to the effects of the Balitsky-Fadin-Kuraev-Lipatov (BFKL) evolution. The measurement is compared with the predictions of various Monte Carlo models based on leading-order and next-to-leading-order calculations including the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi leading-logarithm (LL) parton shower as well as the LL BFKL resummation.
Publisher: Springer Science and Business Media LLC
Date: 14-04-2022
Abstract: A search for supersymmetry in events with two or three low-momentum leptons and missing transverse momentum is performed. The search uses proton-proton collisions at $$ \\sqrt{s} $$ s = 13 TeV collected in the three-year period 2016–2018 by the CMS experiment at the LHC and corresponding to an integrated luminosity of up to 137 fb − 1 . The data are found to be in agreement with expectations from standard model processes. The results are interpreted in terms of electroweakino and top squark pair production with a small mass difference between the produced supersymmetric particles and the lightest neutralino. For the electroweakino interpretation, two simplified models are used, a wino-bino model and a higgsino model. Exclusion limits at 95% confidence level are set on $$ {\\overset{\\sim }{\\upchi}}_2^0/{\\overset{\\sim }{\\upchi}}_1^{\\pm } $$ χ ~ 2 0 / χ ~ 1 ± masses up to 275 GeV for a mass difference of 10 GeV in the wino-bino case, and up to 205(150) GeV for a mass difference of 7.5 (3) GeV in the higgsino case. The results for the higgsino are further interpreted using a phenomenological minimal supersymmetric standard model, excluding the higgsino mass parameter μ up to 180 GeV with the bino mass parameter M 1 at 800 GeV. In the top squark interpretation, exclusion limits are set at top squark masses up to 540 GeV for four-body top squark decays and up to 480 GeV for chargino-mediated decays with a mass difference of 30 GeV.
Publisher: American Meteorological Society
Date: 06-2006
DOI: 10.1175/JHM490.1
Abstract: The objective of this paper is to improve the performance of a hydrologic model through the assimilation of observed discharge. Since an observation of discharge at a certain time is always influenced by the catchment wetness conditions and meteorology in the past, the assimilation method will have to modify both the past and present soil wetness conditions. For this purpose, a bias-corrected retrospective ensemble Kalman filter has been used as the assimilation algorithm. The assimilation methodology takes into account bias in the forecast state variables for the calculation of the optimal estimates. A set of twin experiments has been developed, in which it is attempted to correct the model results obtained with erroneous initial conditions and strongly over- and underestimated precipitation data. The results suggest that the assimilation of observed discharge can correct for erroneous model initial conditions. When the precipitation used to force the model is underestimated, the assimilation of observed discharge can reduce the bias in the modeled turbulent fluxes by approximately 50%. This is due to a correction of the modeled soil moisture. In the case of an overestimation of the precipitation, an improvement in the modeled wetness conditions is also obtained after data assimilation, but this does not lead to a significant improvement in the modeled energy balance. The results in this paper indicate that there is potential to improve the estimation of hydrologic states and fluxes through the assimilation of observed discharge data.
Publisher: Springer Science and Business Media LLC
Date: 04-2022
DOI: 10.1140/EPJC/S10052-022-10127-0
Abstract: A search for low-mass dilepton resonances in Higgs boson decays is conducted in the four-lepton final state. The decay is assumed to proceed via a pair of beyond the standard model particles, or one such particle and a $${\\mathrm{Z}}$$ Z boson. The search uses proton–proton collision data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 137 $$\\,\\text {fb}^{-1}$$ fb - 1 , at a center-of-mass energy $$\\sqrt{s} = 13\\,\\text {TeV} $$ s = 13 TeV . No significant deviation from the standard model expectation is observed. Upper limits at 95% confidence level are set on model-independent Higgs boson decay branching fractions. Additionally, limits on dark photon and axion-like particle production, based on two specific models, are reported.
Publisher: American Meteorological Society
Date: 27-05-2015
Abstract: The Soil Moisture Ocean Salinity (SMOS) satellite mission routinely provides global multiangular observations of brightness temperature TB at both horizontal and vertical polarization with a 3-day repeat period. The assimilation of such data into a land surface model (LSM) may improve the skill of operational flood forecasts through an improved estimation of soil moisture SM. To accommodate for the direct assimilation of the SMOS TB data, the LSM needs to be coupled with a radiative transfer model (RTM), serving as a forward operator for the simulation of multiangular and multipolarization top of the atmosphere TBs. This study investigates the use of the Variable Infiltration Capacity model coupled with the Community Microwave Emission Modelling Platform for simulating SMOS TB observations over the upper Mississippi basin, United States. For a period of 2 years (2010–11), a comparison between SMOS TBs and simulations with literature-based RTM parameters reveals a basin-averaged bias of 30 K. Therefore, time series of SMOS TB observations are used to investigate ways for mitigating these large biases. Specifically, the study demonstrates the impact of the LSM soil moisture climatology in the magnitude of TB biases. After cumulative distribution function matching the SM climatology of the LSM to SMOS retrievals, the average bias decreases from 30 K to less than 5 K. Further improvements can be made through calibration of RTM parameters related to the modeling of surface roughness and vegetation. Consequently, it can be concluded that SM rescaling and RTM optimization are efficient means for mitigating biases and form a necessary preparatory step for data assimilation.
Publisher: American Physical Society (APS)
Date: 06-07-2022
Publisher: Springer Science and Business Media LLC
Date: 15-06-2022
Abstract: Results are presented from a search for charged-lepton flavor violating (CLFV) interactions in top quark production and decay in pp collisions at a center-of-mass energy of 13 TeV. The events are required to contain one oppositely charged electron-muon pair in the final state, along with at least one jet identified as originating from a bottom quark. The data correspond to an integrated luminosity of 138 fb − 1 , collected by the CMS experiment at the LHC. This analysis includes both the production (q → e μ t) and decay (t → e μ q) modes of the top quark through CLFV interactions, with q referring to a u or c quark. These interactions are parametrized using an effective field theory approach. With no significant excess over the standard model expectation, the results are interpreted in terms of vector-, scalar-, and tensor-like CLFV four-fermion effective interactions. Finally, observed exclusion limits are set at 95% confidence levels on the respective branching fractions of a top quark to an e μ pair and an up (charm) quark of 0 . 13 × 10 − 6 (1 . 31 × 10 − 6 ), 0 . 07 × 10 − 6 (0 . 89 × 10 − 6 ), and 0 . 25 × 10 − 6 (2 . 59 × 10 − 6 ) for vector, scalar, and tensor CLFV interactions, respectively.
Publisher: Elsevier BV
Date: 12-2015
Publisher: Copernicus GmbH
Date: 08-02-2012
Abstract: Abstract. The Sequential Importance S ling with Res ling (SISR) particle filter and the SISR with parameter res ling particle filter (SISR-PR) are evaluated for their performance in soil moisture assimilation and the consequent effect on baseflow generation. With respect to the resulting soil moisture time series, both filters perform appropriately. However, the SISR filter has a negative effect on the baseflow due to inconsistency between the parameter values and the states after the assimilation. In order to overcome this inconsistency, parameter res ling is applied along with the SISR filter, to obtain consistent parameter values with the analyzed soil moisture state. Extreme parameter replication, which could lead to a particle collapse, is avoided by the perturbation of the parameters with white noise. Both the modeled soil moisture and baseflow are improved if the complementary parameter res ling is applied. The SISR filter with parameter res ling offers an efficient way to deal with biased observations. The robustness of the methodology is evaluated for 3 model parameter sets and 3 assimilation frequencies. Overall, the results in this paper indicate that the particle filter is a promising tool for hydrologic modeling purposes, but that an additional parameter res ling may be necessary to consistently update all state variables and fluxes within the model.
Publisher: American Geophysical Union (AGU)
Date: 07-2011
DOI: 10.1029/2010WR010292
Publisher: American Physical Society (APS)
Date: 06-07-2022
Publisher: Elsevier BV
Date: 09-2022
Publisher: Copernicus GmbH
Date: 21-07-2011
DOI: 10.5194/HESS-15-2349-2011
Abstract: Abstract. Satellite-based active microwave sensors not only provide synoptic overviews of flooded areas, but also offer an effective way to estimate spatially distributed river water levels. If rapidly produced and processed, these data can be used for updating hydraulic models in near real-time. The usefulness of such approaches with real event data sets provided by currently existing sensors has yet to be demonstrated. In this case study, a Particle Filter-based assimilation scheme is used to integrate ERS-2 SAR and ENVISAT ASAR-derived water level data into a one-dimensional (1-D) hydraulic model of the Alzette River. Two variants of the Particle Filter assimilation scheme are proposed with a global and local particle weighting procedure. The first option finds the best water stage line across all cross sections, while the second option finds the best solution at in idual cross sections. The variant that is to be preferred depends on the level of confidence that is attributed to the observations or to the model. The results show that the Particle Filter-based assimilation of remote sensing-derived water elevation data provides a significant reduction in the uncertainty at the analysis step. Moreover, it is shown that the periodical updating of hydraulic models through the proposed assimilation scheme leads to an improvement of model predictions over several time steps. However, the performance of the assimilation depends on the skill of the hydraulic model and the quality of the observation data.
Publisher: American Physical Society (APS)
Date: 31-05-2022
Publisher: Springer Science and Business Media LLC
Date: 07-2019
Abstract: A search for heavy neutral leptons (HNLs), the right-handed Dirac or Majorana neutrinos, is performed in final states with three charged leptons (electrons or muons) using proton-proton collision data collected by the CMS experiment at $$ \\sqrt{s} $$ s = 13 TeV at the CERN LHC. The data correspond to an integrated luminosity of 138 fb − 1 . The HNLs could be produced through mixing with standard model neutrinos ν . For small values of the HNL mass ( 20 GeV) and the square of the HNL- ν mixing parameter (10 − 7 –10 − 2 ), the decay length of these particles can be large enough so that the secondary vertex of the HNL decay can be resolved with the CMS silicon tracker. The selected final state consists of one lepton emerging from the primary proton-proton collision vertex, and two leptons forming a displaced, secondary vertex. No significant deviations from the standard model expectations are observed, and constraints are obtained on the HNL mass and coupling strength parameters, excluding previously unexplored regions of parameter space in the mass range 1–20 GeV and squared mixing parameter values as low as 10 − 7 .
Publisher: Springer Science and Business Media LLC
Date: 02-2022
Abstract: A search for flavor-changing neutral current interactions of the top quark (t) and the Higgs boson (H) is presented. The search is based on a data s le corresponding to an integrated luminosity of 137 fb − 1 recorded by the CMS experiment at the LHC in proton-proton collisions at $$ \\sqrt{s} $$ s = 13 TeV. Events containing exactly one lepton (muon or electron) and at least three jets, among which at least two are identified as originating from the hadronization of a bottom quark, are analyzed. A set of deep neural networks is used for kinematic event reconstruction, while boosted decision trees distinguish the signal from the background events. No significant excess over the background predictions is observed, and upper limits on the signal production cross sections are extracted. These limits are interpreted in terms of top quark decay branching fractions ( $$ \\mathcal{B} $$ B ) to the Higgs boson and an up (u) or a charm quark (c). Assuming one nonvanishing extra coupling at a time, the observed (expected) upper limits at 95% confidence level are $$ \\mathcal{B} $$ B (t → Hu) 0 . 079 (0 . 11)% and $$ \\mathcal{B} $$ B (t → Hc) 0 . 094 (0 . 086)%.
Publisher: Springer Science and Business Media LLC
Date: 29-06-2022
Abstract: The first collider search for dark matter arising from a strongly coupled hidden sector is presented and uses a data s le corresponding to 138 fb −1 , collected with the CMS detector at the CERN LHC, at $$ \\sqrt{s} $$ s = 13 TeV. The hidden sector is hypothesized to couple to the standard model (SM) via a heavy leptophobic Z′ mediator produced as a resonance in proton-proton collisions. The mediator decay results in two “semivisible” jets, containing both visible matter and invisible dark matter. The final state therefore includes moderate missing energy aligned with one of the jets, a signature ignored by most dark matter searches. No structure in the dijet transverse mass spectra compatible with the signal is observed. Assuming the Z′ boson has a universal coupling of 0.25 to the SM quarks, an inclusive search, relevant to any model that exhibits this kinematic behavior, excludes mediator masses of 1.5–4.0 TeV at 95% confidence level, depending on the other signal model parameters. To enhance the sensitivity of the search for this particular class of hidden sector models, a boosted decision tree (BDT) is trained using jet substructure variables to distinguish between semivisible jets and SM jets from background processes. When the BDT is employed to identify each jet in the dijet system as semivisible, the mediator mass exclusion increases to 5.1 TeV, for wider ranges of the other signal model parameters. These limits exclude a wide range of strongly coupled hidden sector models for the first time.
No related grants have been discovered for Gabrielle De Lannoy.