During the first three years of low luminosity operation, the LHC will facilitate a number of precision tests of the Electroweak sector of the Standard Model. The prospects for measuring the W boson and top quark masses and for probing the charged triple gauge boson couplings at ATLAS are presented here. In each case the most likely analysis methods are described and the statistical and systematic uncertainties which can be expected are reported.
This report summarises studies of associated production of electroweak gauge bosons and jets in proton-proton collisions at LHC with center of mass energy of 8 and 13 TeV. It is based on a selection of results published by the ATLAS Collaboration in the first half of 2017.
An overview of recent measurements of electroweak and top quark physics is given. In particular, total and differential diboson cross sections, limits on anomalous triple gauge couplings as well as top quark production cross sections and properties, such as charge asymmetry, top quark polarization and Wtb vertex measurements, are presented. Proton-proton collision data produced at the LHC at sqrt s = 7 TeV and sqrt s = 8 TeV collected with the ATLAS detector are used.
Measurements of the electroweak production of a $W$ boson in association with two jets at high dijet invariant mass are performed using $\sqrt{s} = 7$ and $8$ TeV proton-proton collision data produced by the Large Hadron Collider, corresponding respectively to 4.7 and 20.2 fb$^{-1}$ of integrated luminosity collected by the ATLAS detector. The measurements are sensitive to the production of a $W$ boson via a triple-gauge-boson vertex and include both the fiducial and differential cross sections of the electroweak process.
Searches for the production of electroweak supersymmetric particles decaying into final states with exactly two isolated, oppositely-charged leptons (electrons, muons), no reconstructed jets and missing transverse momentum are performed using 20.3 fb-1 of 2012 proton-proton collision data at sqrt(s) = 8 TeV recorded with the general purpose detector ATLAS at the Large Hardon Collider. In the absence of any significant excess with respect to the prediction from Standard Model processes, the results are interpreted in the framework of simplified Supersymmetry models.
Recent analyses of top quark production in association with vector bosons are summarized, representing the most precise inclusive and differential cross section measurements of these processes to date. Proton-proton collision data at a center-of-mass energy of $\sqrt{s}=13$ TeV, recorded by the ATLAS and CMS detectors at the LHC are analyzed, corresponding to an integrated luminosity of up to 139 fb$^{-1}$ for each experiment. Comparisons with theory calculations are performed and overall good agreement with standard model predictions are obtained.
In the LHC era, it is crucial to gain a good understanding of the electroweak sector of the Standard Model (SM). Determining the cross-sections of electroweak processes is therefore of great importance, both as prerequisites to Higgs-Boson searches as well as measurements in their own right. For this conference, several new measurements with the data from proton-proton collisions at \sqrt{s} = 7 TeV taken in 2010 and 2011 with the ATLAS detector have been prepared: A measurement of the isolated di-photon cross-section using 37 pb^{-1} collected in 2010 and a measurement of the WZ production cr…
I summarize an extensive ATLAS and CMS electroweak physics program that involves a variety of single boson, diboson, triboson, and vector boson scattering measurements. The relevance of these studies to our understanding of the electroweak sector and electroweak symmetry breaking is emphasized. I describe the recent results and prospects for future measurements.
Evidence for electroweak production of two jets in association with a $Zγ$ pair in $\sqrt{s} = 13$ TeV proton$-$proton collisions at the Large Hadron Collider is presented. The analysis uses data collected by the ATLAS detector in $2015$ and $2016$ that corresponds to an integrated luminosity of $36.1~\mathrm{fb}^{-1}$. Events that contain a $Z$ boson candidate decaying leptonically into either $e^{+}e^{-}$ or $μ^{+}μ^{-}$, a photon, and two jets are selected. The electroweak component is measured with observed and expected significances of $4.1$ standard deviations. The fiducial cross-section…
The ATLAS experiment has performed extensive searches for the electroweak production of charginos, neutralinos and staus. This article summarizes and extends the search for electroweak supersymmetry with new analyses targeting scenarios not covered by previously published searches. New searches use vector-boson fusion production, initial-state radiation jets, and low-momentum lepton final states, as well as multivariate analysis techniques to improve the sensitivity to scenarios with small mass splittings and low-production cross-sections. Results are based on 20 fb$^{-1}$ of proton-proton col…
An observation of electroweak $W^{\pm}Z$ production in association with two jets in proton-proton collisions is presented. The data collected by the ATLAS detector at the Large Hadron Collider in 2015 and 2016 at a centre-of-mass energy of $\sqrt{s} =$ 13 TeV are used, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. Events containing three identified leptons, either electrons or muons, and two jets are selected. The electroweak production of $W^{\pm}Z$ bosons in association with two jets is measured with an observed significance of 5.3 standard deviations. A fiducial cross-section…
A selection of searches by the ATLAS experiment at the LHC for the electroweak production of SUSY particles are used to study their impact on the constraints on dark matter candidates. The searches use $20\,{\rm fb}^{-1}$ of proton-proton collision data at $\sqrt{s}=8$ TeV. A likelihood-driven scan of a five-dimensional effective model focusing on the gaugino--higgsino and Higgs sector of the phenomenological minimal supersymmetric Standard Model is performed. This scan uses data from direct dark matter detection experiments, the relic dark matter density and precision flavour physics results.…
Highlights of ATLAS and CMS measurements involving the production of heavy electroweak gauge bosons, W and Z, at the LHC are presented. Cross sections of single W and Z bosons are studied with very high precision and differential in various kinematic variables. The rapidity differential measurements are shown to have a so far unique impact on our knowledge of proton structure with regards to the strange quark density. The production in association with one or more light or heavy flavour jets is studied. Furthermore measurements of τ final states, W polarisation and the weak mixing angle sin2θW…
Measurements of fiducial cross sections for the electroweak production of two jets in association with a Z-boson are presented. The measurements are performed using 20.3 inverse femtobarns of proton-proton collision data collected at a centre-of-mass energy of sqrt(s)=8 TeV by the ATLAS experiment at the Large Hadron Collider. The electroweak component is extracted by a fit to the dijet invariant mass distribution in a fiducial region chosen to enhance the electroweak contribution over the dominant background in which the jets are produced via the strong interaction. The electroweak cross sect…
This Letter presents the first study of $W^{\pm}W^{\pm}jj$, same-electric-charge diboson production in association with two jets, using 20.3 fb$^{-1}$ of proton--proton collision data at $\sqrt{s}=8$ TeV recorded by the ATLAS detector at the Large Hadron Collider. Events with two reconstructed same-charge leptons ($e^\pm e^\pm$, $e^\pm μ^\pm$, and $μ^\pm μ^\pm$) and two or more jets are analyzed. Production cross sections are measured in two fiducial regions, with different sensitivities to the electroweak and strong production mechanisms. First evidence for $W^{\pm}W^{\pm}jj$ production and e…
The cross-section for the production of two jets in association with a leptonically decaying Z boson ($Zjj$) is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV, using data recorded with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 3.2 fb$^{-1}$. The electroweak $Zjj$ cross-section is extracted in a fiducial region chosen to enhance the electroweak contribution relative to the dominant Drell-Yan $Zjj$ process, which is constrained using a data-driven approach. The measured fiducial electroweak cross-section is $σ^{Zjj}_{…
Many supersymmetry models feature gauginos and also sleptons with masses below a few hundred GeV. These can give rise to direct pair production rates at the LHC that can be observed in the data sample recorded by the ATLAS detector. The talk presents results from searches for gaugino and slepton pair production in final states with leptons.
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell $W$ and $Z$ bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of $\sqrt{s}$ = 13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The tw…
This paper reports on a search for the electroweak diboson ($WW/WZ/ZZ$) production in association with a high-mass dijet system, using data from proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV. The data, corresponding to an integrated luminosity of 35.5 fb$^{-1}$, were recorded with the ATLAS detector in 2015 and 2016 at the Large Hadron Collider. The search is performed in final states in which one boson decays leptonically, and the other boson decays hadronically. The hadronically decaying $W/Z$ boson is reconstructed as either two small-radius jets or one large-radi…
This Letter presents the observation and measurement of electroweak production of a same-sign $W$ boson pair in association with two jets using 36.1 fb$^{-1}$ of proton-proton collision data recorded at a center-of-mass energy of $\sqrt{s}=13$ TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed in the detector fiducial phase-space region, defined by the presence of two same-sign leptons, electron or muon, and at least two jets with a large invariant mass and rapidity difference. A total of 122 candidate events are observed for a background expectation of $69 \pm 7…
Measurement of electroweak $Z(ν\barν)γjj$ production and limits on anomalous quartic gauge couplings in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
Fiducial and differential cross-section measurements of electroweak $Wγjj$ production in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
The results of a search for electroweakino pair production $pp \rightarrow \tildeχ^\pm_1 \tildeχ^0_2$ in which the chargino ($\tildeχ^\pm_1$) decays into a $W$ boson and the lightest neutralino ($\tildeχ^0_1$), while the heavier neutralino ($\tildeχ^0_2$) decays into the Standard Model 125 GeV Higgs boson and a second $\tildeχ^0_1$ are presented. The signal selection requires a pair of $b$-tagged jets consistent with those from a Higgs boson decay, and either an electron or a muon from the $W$ boson decay, together with missing transverse momentum from the corresponding neutrino and the stable…
A search is presented for anomalous quartic gauge boson couplings in vector-boson scattering. The data for the analysis correspond to $20.2$ fb$^{-1}$ of $\sqrt{s}=8$ TeV $pp$ collisions, and were collected in 2012 by the ATLAS experiment at the Large Hadron Collider. The search looks for the production of $WW$ or $WZ$ boson pairs accompanied by a high-mass dijet system, with one $W$ decaying leptonically, and a $W$ or $Z$ decaying hadronically. The hadronically decaying $W/Z$ is reconstructed as either two small-radius jets or one large-radius jet using jet substructure techniques. Constraint…
This paper presents results of searches for electroweak production of supersymmetric particles in models with compressed mass spectra. The searches use 139 fb$^{-1}$ of $\sqrt{s}=13$ TeV proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider. Events with missing transverse momentum and two same-flavor, oppositely charged, low transverse momentum leptons are selected, and are further categorized by the presence of hadronic activity from initial-state radiation or a topology compatible with vector-boson fusion processes. The data are found to be consistent wi…
A search for the electroweak production of charginos and sleptons decaying into final states with two electrons or muons is presented. The analysis is based on 139 fb$^{-1}$ of proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider at $\sqrt{s}=13$ TeV. Three $R$-parity-conserving scenarios where the lightest neutralino is the lightest supersymmetric particle are considered: the production of chargino pairs with decays via either $W$ bosons or sleptons, and the direct production of slepton pairs. The analysis is optimised for the first of these scenarios, but the …
This review covers results at a centre-of-mass energy of $\sqrt{s}=13$ TeV from the ATLAS experiment that have been published, or submitted for publication, up to April 2020. It summarizes results on the inclusive production cross-section measurements of boson pairs and of the electroweak production of diboson in association with two jets. The measurements either use the full integrated luminosity of 139 $\text{fb}^\text{-1}$ collected by the ATLAS detector at the LHC from 2015 to 2018, or a partial dataset of 36 $\text{fb}^\text{-1}$. The inclusive production rates of diboson are studied to h…
A search for electroweak production of supersymmetric particles in scenarios with compressed mass spectra in final states with two low-momentum leptons and missing transverse momentum is presented. This search uses proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015-2016, corresponding to 36.1 fb$^{-1}$ of integrated luminosity at $\sqrt{s}=13$ TeV. Events with same-flavor pairs of electrons or muons with opposite electric charge are selected. The data are found to be consistent with the Standard Model prediction. Results are interpreted using simpl…
A search for the electroweak production of charginos, neutralinos and sleptons decaying into final states involving two or three electrons or muons is presented. The analysis is based on 36.1 fb$^{-1}$ of $\sqrt{s}=13$ TeV proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider. Several scenarios based on simplified models are considered. These include the associated production of the next-to-lightest neutralino and the lightest chargino, followed by their decays into final states with leptons and the lightest neutralino via either sleptons or Standard Model gauge …
Measurement of the cross-sections of the electroweak and total production of a $Z γ$ pair in association with two jets in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
A search for a chargino$-$neutralino pair decaying via the 125 GeV Higgs boson into photons is presented. The study is based on the data collected between 2015 and 2018 with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 139 fb$^{-1}$ of $pp$ collisions at a centre-of-mass energy of 13 TeV. No significant excess over the expected background is observed. Upper limits at 95% confidence level for a massless $\tildeχ^{0}_{1}$ are set on several electroweakino production cross-sections and the visible cross-section for beyond the Standard Model processes. In the context…
Search for electroweak-scale dijet resonances using trigger-level analysis with the ATLAS detector in $132$ fb$^{-1}$ of $pp$ collisions at $\sqrt{s} = 13$ TeV
Differential cross-section measurements are presented for the electroweak production of two jets in association with a $Z$ boson. These measurements are sensitive to the vector-boson fusion production mechanism and provide a fundamental test of the gauge structure of the Standard Model. The analysis is performed using proton-proton collision data collected by ATLAS at $\sqrt{s}$=13 TeV and with an integrated luminosity of 139 fb$^{-1}$. The differential cross-sections are measured in the $Z\rightarrow \ell^+\ell^-$ decay channel ($\ell=e,μ$) as a function of four observables: the dijet invaria…
The production of a $Z$ boson and a photon in association with a high-mass dijet system is studied using 20.2fb$^{-1}$ of proton-proton collision data at a centre-of-mass energy of $\sqrt{s}$ = 8 TeV recorded with the ATLAS detector in 2012 at the Large Hadron Collider. Final states with a photon and a Z boson decaying into a pair of either electrons, muons, or neutrinos are analysed. Electroweak and total $pp \to Zγj j$ cross-sections are extracted in two fiducial regions with different sensitivities to electroweak production processes. Quartic couplings of vector bosons are studied in region…
This paper presents a measurement of the electroweak production of two jets in association with a $Zγ$ pair, with the $Z$ boson decaying into two neutrinos. It also presents a search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results use data from LHC proton-proton collisions at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector and corresponding to an integrated luminosity of 139 fb$^{-1}$. The event signature, shared by all benchmark processes considered for the measuremen…
Two analyses searching for the production of supersymmetric particles through the electroweak interaction are presented: the chargino search, targeting the pair production of charginos decaying into W bosons and neutralinos, and the displaced track search, looking for charged tracks arising from the decays of higgsinos into pions. These searches target compressed phase spaces, where the mass difference between the next-to-lightest and lightest supersymmetric particle is relatively small. The searches use proton-proton collision data collected at a centre-of-mass energy of 13 TeV with the ATLAS…
A search for electroweak $t\bar{t}Wj$ production in multileptonic final states at $\sqrt{s} = 13$ TeV with the ATLAS detector and bounds on effective field theory operators
EUROPEAN ORGANISATION FOR NUCLEAR RESEARCH (CERN)（欧洲核子研究组织（CERN））
Electroweak diboson production in association with a high-mass dijet system in semileptonic final states from $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
EUROPEAN ORGANISATION FOR NUCLEAR RESEARCH (CERN)（欧洲核子研究中心）
Measurements of electroweak gauge-boson pair-production in sqrt(s) = 7 and 8 TeV pp collisions at the LHC probe self-couplings and interference effects to an accuracy of O(10%) or better. ATLAS measurements of ZZ and WZ production at both center of mass energies, and of WW, Zgamma and Wgamma production at sqrt(s) = 7 TeV, are presented. Total, fiducial, and differential cross sections are given, along with limits on anomalous triple-gauge couplings.
The production of single top quarks allows to study the interplay of top quark physics and the electroweak sector of the standard model. Deviations from predictions can be a hint for physics beyond the standard model. The t-channel is the dominant production mode for single top quarks at the LHC. This talk presents the latest measurements from the ATLAS and CMS collaborations.
Cross-sections of associated production of a Higgs boson decaying into bottom-quark pairs and an electroweak gauge boson, $W$ or $Z$, decaying into leptons are measured as a function of the gauge boson transverse momentum. The measurements are performed in kinematic fiducial volumes defined in the `simplified template cross-section' framework. The results are obtained using 79.8 fb$^{-1}$ of proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. All measurements are found to be in agreement with the Standard Model predictions,…
These proceedings present measurements from ATLAS and CMS using proton-proton collisions with center-of-mass energies of 7 TeV and 8 TeV at the Large Hadron Collider that are sensitive to interactions between electroweak gauge bosons. Included analyses sensitive to triple gauge couplings are electroweak Z production and many diboson processes ($W^+W^-$, $W^{\pm}Z$, $ZZ$, $W^{\pm}γ$, and $Zγ$). In addition, $γγ\rightarrow W^+W^-$ production, $WVγ$ production, where $V=W,Z$, and $W^{\pm}W^{\pm}jj$ production are presented as probes of quartic gauge couplings.
The investigation of the electroweak symmetry breaking is one of the primary tasks of the experiments at the CERN Large Hadron Collider (LHC). The potential of the ATLAS experiment for the discovery of the Higgs boson(s) in Standard Model and Minimal Supersymmetric Standard Model is presented, with emphasis on studies which have been completed recently.
The electroweak boson inclusive production cross sections and their ratios are described in the electron and muon decay channels. The observation of W and Z bosons in the tau decay channel is also presented. The data from pp collisions at 7 TeV were collected during 2010 using the ATLAS detector at the Large Hadron Collider and the results are compared to predictions at NNLO in perturbative QCD.
Evidence for longitudinally polarised $Z$ bosons in electroweak $W^{\pm}Z$ production in association with two jets from $pp$ collisions at $\sqrt{s} = $ 13 TeV and 13.6 TeV with the ATLAS detector
A method is proposed to calculate the confidence level for agreement of data with the Standard Model (SM) by combining information from direct and indirect Higgs Boson searches. Good agreement with the SM is found for $m_H \simeq 120$ GeV using the observables most sensitive to $m_H$: $A_l$ and $m_W$. In particular, quantum corrections, as predicted by the SM, are observed with a statistical significance of forty-four standard deviations. However, apparent deviations from the SM of 3.7$σ$ and 2.8$σ$ are found for the Z$ν\barν$ and right-handed Zb$\bar{\rm b}$ couplings respectively. The maximu…
We present the most recent precision electroweak measurements of single $W$ and $Z$ boson cross section and properties from the LHC and Tevatron colliders, analyzing data collected by ATLAS, CDF, CMS, D0, and LHCb detectors. The results include the measurement of the single $W$ and $Z$ boson cross section at LHC, the differential cross section measurements, the measurement of $W$ boson mass, the measurement of $W$ and $Z$ charge asymmetry. These measurements provide precision tests on the electroweak theory, high order predictions and the information can be used to constraint parton distributi…
The prospects for electroweak measurements at the Large Hadron Collider (LHC) are discussed. In addition to high-luminosity results, special emphasis is placed on early start-up measurements with a total luminosity ranging from 10/pb to 100/pb, using the general-purpose detectors ATLAS and CMS and their initially larger calibration and alignment uncertainties. Topics discussed here include inclusive W and Z production, W-boson mass, Z forward-backward asymmetry, Z-plus-jets production and di-boson production, the latter constraining trilinear electroweak gauge couplings. (Invited talk at the 3…
Search for electroweak production of vector-like leptons in $τ$-lepton and $b$-jet final states in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
利用ATLAS探测器在13 TeV pp碰撞中搜索向量类轻子的电弱产生，设定了向量类轻子质量的下限为910 GeV，并对超对称模型参数进行约束。
Measurements of the di- and multiboson production cross sections at the LHC constitute stringent tests of the electroweak sector of the Standard Model and provide a model-independent means to search for new physics at the TeV scale. The ATLAS collaboration has performed studies of $ZZ$, $WZ$, $WW$, $WWγ$ and $WZγ$ productions in various decay modes at $\sqrt{s}$=8 and 13 TeV, including total, fiducial and differential cross-section measurements. These results are compared to state-of-the art theory predictions and are used to provide constraints on new physics, by setting limits on anomalous g…
Measurements of electroweak $W^{\pm}Z$ boson pair production in association with two jets in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
Several electroweak precision measurements are performed by the ATLAS and CMS collaborations at the LHC. The main ones are carried out using Drell-Yan production of single W and Z boson. They regard the measurement of the production cross sections of W and Z bosons, the mass of the W boson, and $\sin^2θ_W$. The results of the $\sin^2θ_W$ measurements have an accuracy of approximately twice that reached at LEP and SLD. Other measurements reported are about the Drell-Yan differential production cross section.
