Conveners
Top and Electroweak Physics
- Maria Jose Costa (IFIC Valencia (ES))
- Pedro Vieira De Castro Ferreira Da Silva (CERN)
- Cen Zhang (Institute of High Energy Physics, Chinese Academy Sciences)
Top and Electroweak Physics
- Pedro Vieira De Castro Ferreira Da Silva (CERN)
- Cen Zhang (Institute of High Energy Physics, Chinese Academy Sciences)
- Maria Jose Costa (IFIC Valencia (ES))
Top and Electroweak Physics
- Pedro Vieira De Castro Ferreira Da Silva (CERN)
- Maria Jose Costa (IFIC Valencia (ES))
- Cen Zhang (Institute of High Energy Physics, Chinese Academy Sciences)
Top and Electroweak Physics
- Pedro Vieira De Castro Ferreira Da Silva (CERN)
- Cen Zhang (Institute of High Energy Physics, Chinese Academy Sciences)
- Maria Jose Costa (IFIC Valencia (ES))
Modified interactions in the electroweak sector may lead to scattering amplitudes that grow with energy compared to their Standard Model (SM) counterparts. We present a detailed study of all 2โ2 scattering amplitudes involving at least one top quark and a pair of EW bosons. We analyse the high energy behaviour of the amplitudes using the Standard Model Effective Field Theory (SMEFT) to...
We analyze constraints on anomalous tWb couplings that parameterize the possible contribution of New Physics to the weak tWb vertex. We take into account indirect constraints obtained from B-physics ($B\to X_s \gamma$, $B\to X_s l^+l^-$, $B$-$\bar B$ oscillations) and direct constraints from the t-channel single top quark production. In two-dimensional scenarios when different pairs of the...
The Matrix Element Method is a promising multi-variate analysis method which offers an optimal approach to compare theory and experiment. However, until recently its usage has been limited by the fact that only leading-order predictions could be employed. This rather crude approximation of the underlying probability distribution can introduce a significant bias into the analysis which requires...
Photon-induced processes in proton-proton interactions have become recently very topical. The large energy at the LHC, when combined with relatively large luminosity at run II, allows starting the exploration of such processes.
We discuss the production of $W^+ W^-$ pairs and $t \bar t$ quark-antiquark pairs in proton-proton collisions induced by two-photon fusion including, for a first time,...
(Includes single top) Measurements of top quark properties using data collected by the CMS experiment are presented. Among them, latest results on top mass, ttbar spin correlations, Yukawa coupling, charge asymmetries, and others will be discussed.
Top quark production can probe physics beyond the SM in different ways. This talks reviews the current limits on FCNC searches in the top sector, and EFT interpretations in many top quark production modes.
Precise measurements of the properties of the top quark test the Standard Model (SM) and can be used to constrain new physics models. The top-quark is predicted in the SM to decayalmost exclusively into a W boson and a b-quark. We present a wide range of searches for non-SM top quark decays using the 13 TeV ATLAS datasets, including t->q H and t->q Z. In addition, measurements of the spin...
The latest measurements of the top quark mass using the ATLAS experiment are presented. A measurement based on a multi-dimensional template fit that can constrain the uncertainties on the energy measurements of jets is presented and combined with measurements using dilepton and all-hadronic events. In addition, an analysis of the top quark mass using leptonic kinematic variables is discussed....
I present results through three loops for soft anomalous dimensions that control soft-gluon emission in processes involving the top quark. In particular I present results for channels in single-top production and top-pair production as well as for processes with new physics, including tZ, tZ', t gamma, and tH- production. These calculations are ingredients to resummations at N3LL accuracy and...
The study of top-quark production and decay is central in the LHC physics programme, allowing to test the Standard Model and offering a window on possible new physics. Precise theoretical predictions are crucial for these analysis.
In this talk, we report on a new calculation of the next-to-next-to-leading order QCD radiative corrections to the inclusive production of top-quark pairs at hadron...
Latest results on inclusive top quark pair and single top quark production cross sections are presented using proton-proton collision data collected by CMS. The single top quark analyses investigate separately the production of top quarks via t-channel exchange, via associated production with a W boson (tW), and via the s-channel.
Differential measurements of top quark pair and single top quark production cross sections are presented using data collected by CMS. The cross sections are measured as a function of various kinematic observables of the top quarks and the jets and leptons of the event final state. The results are confronted with precise theory calculations. Multidifferential tt cross sections are presented and...
Measurements of the inclusive and differential top-quark pair production cross sections in proton-proton collisions at 13 TeV with the ATLAS detector at the Large Hadron Collider are presented. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. Differential measurements of the kinematic properties of the top quark production are...
Measurements of single-top-quark production in proton-proton collisions are presented based on the 8 TeV and 13 TeV ATLAS datasets. The recent combination of the ATLAS and CMS Run 1 single-top-quark measurements is discussed. This combination leads to the most precise direct measurement of the CKM-matrix element Vtb. An interesting quantum effect is the interference of tW and top-quark-pair...
In the context of the Standard Model effective field theory (SMEFT), we study the LHC sensitivity to four fermion operators involving heavy quarks by employing cross section measurements in the $\text{t}\overline{\text{t}}\text{b}\overline{\text{b}}$ final state. Starting from the measurement of total rates, we progressively exploit kinematical information and machine learning techniques to...
Manifest gauge-invariance requires that observable states in the standard-model are described by composite operators, which involve additional Higgs contributions beyond perturbation theory. This field-theoretical effects has been confirmed in lattice simulations. It has experimentally accessible consequences, of which two will be explored.
One is a non-trivial modification of the off-shell...
The large centre-of-mass energy available at the proton-proton collider LHC allows for the copious production of top-quark-antiquark pairs in association with electroweak gauge bosons (W / Z / gamma) at high transverse momenta. The tt ฬZ and tt ฬW production cross sections are simultaneously measured using a combined fit in several analysis regions. The measurement of the tt ฬZ cross section...
(Does not include EFT interpretation of ttV and any FCNC) A comprehensive set of measurements of top quark pair production in association with EWK bosons (W, Z or ษฃ) is presented.
Measurements of the production cross-section of top-quark-antiquark pairs with additional jets provide important tests of quantum chromodynamics (QCD). The ATLAS experiment has measured several final state observables that are sensitive to additional radiation in top-quark-antiquark final states at 13 TeV. These measurements are compared to predictions of modern Monte Carlo generators based on...
We investigate the prospects for discovering a top quark decaying into
one light Higgs boson ($h^0$) along with a charm quark
in top quark pair production
at the CERN Large Hadron Collider (LHC) and future hadron colliers.
A general two Higgs doublet model is adopted to study the signature
of flavor changing neutral Higgs (FCNH) interactions with $t \to c h^0$,
followed by $h^0 \to WW^*$...
(Does not include EFT interpretation and any FCNC) A comprehensive set of measurements of top quark pair and single top quark production in association with light and b-jets is presented. The status of the search for four top quark production, to which the LHC experiments are starting to be sensitive, and that has important BSM re-interpretations, is also reported.
Results from LHCb on top production in the forward region are presented. LHCb provides unique coverage at forward rapidities at the LHC, and measurements at LHCb probe a unique kinematic range, providing novel constraints on parton distribution functions. The potential for future measurements at LHCb, following major upgrades that will enable the collection of integrated luminosities of at...
In top quark production, the polarization of top quarks, decided by the chiral structure of couplings, is likely to be modified in the presence of any new physics contribution to the production. Hence the same is a good discriminator for those new physics models wherein the couplings have a chiral structure different than that in the Standard Model (SM). In this note we construct probes of the...
We have performed an object tagging approach to identify boosted top quark decaying to electron or muon final state without an explicit use of the lepton. When top quark is produced with large transverse momentum, its daughter lepton has a hadronic activity in it's neighborhood, and hence standard lepton identification and isolation criteria are affected. We have come up with novel observables...
At TeV-scale hadron colliders, such at the CERN LHC and proposed future facilities at $\sqrt{s}=28-100$ TeV, single and pair production of top quarks invariably constitute a major background in multi-lepton searches for new, TeV-scale particles, such as $W'$ gauge bosons, smuons $(\tilde{\mu})$, and heavy neutrinos $(N)$. Due to imperfect tagging efficiencies, however, vetoing events according...
The LHC Top Working Group was established to perform combinations of
top-quark related measurements from the LHC experiments, and provides a
forum to discuss interpretation of LHC measurements in the light of
the most recent theory developments. In this talk the challenges and
the progress in such combinations are presented together with the
latest results, including the recently published...
The future circular collider (FCC) study released a conceptual design report (CDR) in January 2019. FCC-ee can provide $e^+e^โ$ collisions with center-of-mass energies of up to 365 GeV and luminosities at the highest energy of 1.4 $10^{34}$ cm$^{-2}$s$^{-1}$ in up to four IPs. Threshold scans enable precision measurements of the top mass and width constraining $\alpha_s$ and $Y_T$, while a run...
The Compact Linear Collider (CLIC) is a mature option for a future electron-positron collider operating at centre-of-mass energies of up to 3 TeV. CLIC will be built and operated in a staged approach with three centre-of-mass energy stages currently assumed to be 380 GeV, 1.5 TeV, and 3 TeV. This contribution discusses the prospects for precision measurements of top-quark production and...
In this talk, we briefly describe the recent progress on the inclusion of mixed QCD-QED corrections for collider observables. In particular, we developed a formalism to extend qt-resummation to deal with simultaneous emission of gluons and photons. We applied it to Z-production at colliders, and discuss extensions to more complicated final states.
Precision measurements of the production cross sections of W and Z bosons in proton-proton collisions provide stringent tests of perturbative QCD and yield important information about the parton distribution functions (PDFs) for quarks within the proton. We report measurements of fiducial integrated and differential cross sections for inclusive W+, Wโ and Z boson production, analysed in the...
The production of prompt isolated photons at hadron colliders provides stringent tests of perturbative QCD and can be used to evaluate probability density functions of partons in the proton. In this talk, we present the measurements of the isolated-photon plus two jets and the inclusive isolated-photons cross sections, both measured using proton-proton collision data collected by the ATLAS...
We present a measurement of the shape of the Z boson rapidity for $Z/\gamma^{*} \to\mu^+\mu^- $ produced in $ p\bar p$ collision at $\sqrt s=$1.96 TeV. We use 8.6 fb$^{-1}$ of $ p\bar p$ data collected by the D0 detector at the Tevatron collider. The results are compared to NNLO QCD predictions using different sets of Parton Density Functions. We also present a measurement of the shape of...
The study of the associated production of vector bosons and jets constitutes an excellent testbench to check numerous QCD predictions. Total and differential cross sections of vector bosons produced in association with jets have been studied in pp collisions at 7, 8 and 13 TeV center-of-mass energies. Differential distributions as function of a broad range of kinematical observables are...
Measurements of weak boson production in association with jets are presented. First, differential cross sections for Z-boson and W-boson production in association with jets are presented, with the measurements performed using proton-proton collisions at โs = 8 TeV. The data are compared to next-to-leading order QCD calculations and predictions from a variety of different parton distribution...
Electroweak bosons are created in the hard scattering processes at the initial stage of heavy-ion collisions and they are insensitive to the presence of the strongly-interacting medium. This makes them clean probes of the initial-state effects in heavy-ion collisions, such as the nuclear modification of the Parton Distribution Functions (nPDFs). Furthermore, their measurement in heavy-ion...
In this talk we review the recent developments of the evaluation of the two-loop virtual correction to the electron-muon scattering, $\mu e \to\mu e$, at Next-to-Next-to-Leading order in QED. These radiative corrections are relevant for the analysis of the MUonE experiment, recently proposed at CERN. MUonE aims at the high precision determination of the QED running coupling constant in the...
The electroweak sector of the Standard Model can be tested via precision measurements of fundamental observables. Measurements of the Drell-Yan production of Z bosons at the LHC provide a benchmark of our understanding of perturbative QCD and electroweak processes. The ATLAS collaboration has recently used such measurements to evaluate the effective leptonic weak mixing angle using data...
This talk reviews precision EW measurements at CMS.
he LHCb detector at the LHC offers unique coverage of forward rapidities, allowing the experiment to play an important role in precision measurements of electroweak physics at the LHC. Precision cross-section measurements (from LHC Runs 1 and 2) will be presented. Prospective studies will also be presented, including the potential of a measurement of the W boson mass using the LHCb Run 2 data,...
The parameters of the electroweak theory are determined in a combined electroweak and QCD analysis using all deep-inelastic e + p and e โ p neutral current and charged current scattering cross sections published by the H1 Collaboration, including data with longitudinally polarised lepton beams. The mass of the W boson in the on-shell scheme is determined as $m_W = 80.520\pm 0.115$ GeV. The...
The associated production of vector bosons V (W, Z or gamma) and jets originating from heavy-flavour (c or b) quarks is a large background source in measurements of other standard model processes, Higgs boson studies, and many searches for physics beyond the SM. The study of events with a vector boson accompanied by heavy-flavour jets is crucial to refine the theoretical calculations in...
Weak vector boson scattering (VBS) is a sensitive probe of new physics effects in the electroweak symmetry breaking. Currently, experimental results at the LHC are interpreted in the effective field theory approach, where possible deviations from the Standard Model in the quartic-gauge-boson couplings are often described by 18 dimension-8 operators. By assuming that a UV completion exists, we...
Due to the current gap between the electroweak scale and the scale of New Physics, the use of electroweak effective approaches is justified. A linear realization of the electroweak symmetry breaking with the Higgs forming a doublet is a first possibility (SMEFT), but we prefer to use the more general non-linear realization, being the Higgs a scalar singlet with independent couplings (EWET or...
Measurements of electroweak boson pair production at the LHC constitute a stringent test of the electroweak sector and provide a model-independent means to search for new physics at the TeV scale. In this talk, we present recent results for inclusive WW and WZ production in proton-proton collisions at โs=13 TeV, including polarisation studies in the WZ final state. The precision measurements...
In this talk, we present a number of recent measurements of inclusive ZZ and Z๐พ production in proton-proton collisions at โs=13 TeV at ATLAS. The unfolded differential cross section for ZZ->4l as a function of the four-lepton invariant mass is presented and compared to state-of-the-art Standard Model calculations. If available, an additional measurement of ZZ production will be presented for...
The scattering of electroweak bosons tests the gauge structure of the Standard Model and is sensitive to anomalous quartic gauge couplings. In this talk, we present recent results on vector-boson scattering from the ATLAS experiment using proton-proton collisions at โs=13 TeV. This includes the observation of WZ and same-sign-WW production via vector-boson scattering along with a measurement...
A search for the production of three massive vector bosons in WWW, WWZ and WZZ final states is presented, using proton-proton collision data collected by the ATLAS experiment at โs=13 TeV. The analysis utilises multiple search channels. WWW production is probed using a fully-leptonic decay channel, with three-charged leptons and missing transverse momentum, and a semi-leptonic decay channel...
This talk review recent measurements of multiboson production and constraints on anomalous gauge couplings.
The High-Luminosity Large Hadron Collider (HL-LHC) is expected to deliver an integrated luminosity of up to 3000 fb-1. The very high instantaneous luminosity will lead to about 200 proton-proton collisions per bunch crossing (โpileupโ) superimposed to each event of interest, therefore providing extremely challenging experimental conditions. Prospects for selected Standard Model (SM)...
The Future Circular Collider with electron-positron beams (FCC-ee) should provide improvements of the electroweak precision measurement concerning Z, W, H and their masses by a large factor over the present status. The unparalleled experimental precision would open, via Electroweak loop corrections, a broad discovery potential for new, at least weakly interacting particles up to high energy...
In the Standard Model theory, the mass of the W boson is predicted with an uncertainty of 4 MeV whereas the current experimental accuracy is of 12 MeV. Improving the accuracy of the W mass measurement is a crucial test of the overall consistency of the SM and any deviation might reveal the emergence of new physics. With more than 2x10^8 W pairs produced at the W threshold energy and above, the...
The Circular Electron Positron Collider (CEPC) project aims to build a circular electron-positron collider capable of precision physics measurements at center-of-mass energies ranging from 90 GeV to 240GeV. The CEPC has a total circumference of at least one hundred kilometers and at least two interaction points. In its 10 years operation at 240 GeV, it will collect more than one million Higgs...
The 3rd generation quarks are, due to their large mass, highly sensitive probes for new physics connected to the electroweak symmetry breaking. Linear e+e- colliders allow for clean measurements of heavy quark final states between the Z-Pole and the TeV scale with sensitivities to different aspects of the manifestations of new physics in the extracted electroweak couplings. At the same time...
The Large Hadron-electron Collider (LHeC) is a proposed upgrade of the LHC at CERN. It consists of an ERL providing electrons to collide with the HL-LHC, HE-LHC and the FCC-hh proton beams achieving centre-of-mass energies 1.3-3.5 TeV, respectively, and luminosities $\sim 10^{34}$ cm$^{โ2}$ s$^{-1}$. These large luminosities and the corresponding cross sections provide huge possibilities for...
