We present recent diboson production measurements from the D0 experiment at Fermilab's Tevatron collider. The production of ZZ was observed using leptonic final states. Zgamma->nunugamma was observed and used to set the most stringent limits from a hadron collider on anomalous Zgammagamma and ZZgamma trilinear gauge couplings (TGCs). WW events with leptonic final states and WW+WZ events with semi-leptonic final states were used to set limits on anomalous WWZ and WWgamma TGCs. Finally, limits on anomalous WWZ and WWgamma TGCs were obtained from a combination of the fully-leptonic Wgamma, WW, and WZ channels and the semi-leptonic WW and WZ channels, giving the most stringent limits from a hadron collider.
Scrutiny of the structure of electroweak gauge boson self-interactions through triple and quartic gauge boson couplings (TGCs and QGCs) constitutes an important part of the physics program of the Large Hadron Collider (LHC). Triboson production and vector boson scattering (VBS) are directly sensitive to QGCs while vector boson fusion (VBF) offers a new window in the study of TGCs, which is complementary to conventional measurements using diboson production. In this contribution, an overview of recent TGC and QCG measurements using triboson production, VBS and VBF by the ATLAS and CMS experimen…
A study is made of the feasibility of maximum likelihood fits to determine M_W and triple gauge boson couplings using only those experimental kinematical variables that are well measured. A computational tool to calculate theoretical probabilities for those kinematical variables is discussed and then applied to samples of unweighted events produced by an event generator. Detailed results on the M_W determination for semileptonic final states in W-pair production show the feasibility of the method. For TGCs one result is presented as an illustration.
We present high statistics measurements of diboson production in ppbar collisions at the DØ experiment in multiple channels, including $ZZ \to llll$, $Zγ\to ννγ$, $WW \to l νl ν$ and $WW/WZ \to l νjj$. These measurements both test physics beyond the standard model and demonstrate the sensitivity of hadron colliders to rare signals such as Higgs boson production.
At the Fermilab Tevatron, the CDF detector is used to study diboson production in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV. We report recent diboson production measurements, limits on anomalous triple gauge couplings and latest results from semi-leptonic diboson searches.
The increasing size of the data recorded by the CDF and DØ experiments at the Tevatron collider at $\sqrt{s}=$ 1.96 TeV makes the diboson physics program more accessible for probes of the electroweak gauge structure in the Standard Model. Here we summarize the most recent measurements of the diboson cross sections and limits on the trilinear gauge boson couplings.
The most recent measurements of the trilinear gauge boson couplings from the diboson production at the D0 experiment has been presented. The analyzed final states are Zgamma->vvgamma, and WW->lvlv, and WW+WZ->lvjj. We also present results obtained combining all final states involving the W boson. These results represent the most strigent limits set to date at the hadron collider.
We present the latest results on the production of WW, WZ, Wgamma, Zgamma and ZZ events at the Fermilab Tevatron Collider. The results are based on the analyses of 0.2 -- 2 /fb of data collected in p pbar collisions at sqrt(s) = 1.96 TeV by CDF and DO experiments during the Tevatron Run II. Analyses of the diboson production processes provide crucial test of the Standard Model, directly probing its predictions on the Trilinear Gauge Couplings.
This is a report at the conference Physics in Collision 2013. The experimental results on physics of diboson production are reviewed. The measurements use $pp$ collision at the LHC with center-of-mass energy $\sqrt{s}$ = 7 and 8 ~TeV, and $p\bar{p}$ collision at the Tevatron with $\sqrt{s}$ = 1.96~TeV. These include measurements of W$γ$, Z$γ$, WW, WZ and ZZ production. The results are compared with Standard Model predictions, and are interpreted in terms of constraints on charged and neutral anomalous triple gauge couplings.
Recent searches performed by the CDF and D0 collaborations at the Tevatron for diboson production in final states containing heavy-flavor jets are reported. The searches for WZ and ZZ can be regarded as the ultimate benchmark for the corresponding searches for a low-mass Higgs boson in the WH and ZH final states. Using the exact same techniques as for those Higgs boson searches, the D0 collaboration measured a cross section for WZ/ZZ production of 1.13 +/- 0.36 times its expectation in the standard model, with a diboson signal significance of 3.3 standard deviations (2.9 expected).
The measurement of the triple gauge couplings (TGCs) is a central part of diboson studies at the LHC. In this letter we consider the $Zγ$ process and include anomalous TGCs (aTGCs) in the event generation at next-to-next-to-leading order QCD accuracy (NNLO+PS) within the MiNNLO$_{\rm PS}$ framework. While our implementation is fully general and applies to both $Z\to \ell^+\ell^-$ and $Z\to ν\barν$ decays, we focus here on the $ν\barνγ$ final state. After validation of our simulation of $ν\barνγ$ events, for which NNLO+PS accuracy is achieved for the first time, the effects of aTGCs on various …
Recent developments in the study diboson production at the Tevatron are reviewed. These include indications at the 2.6 sigma level for a radiation amplitude zero in the W gamma process at D0 and a 4.4 sigma signal for ZZ production in hadron collisions from CDF.
A general review of the latest results about single and double vector boson production in the multipurpose experiments at LHC (ATLAS and CMS) and at Tevatron (CDF and D0) will be presented. The review will focus on boson production, while a more detailed report about W and Z properties can be found elsewhere. Only leptonic decays into electrons and muons will be considered.
This paper presents an overview of the diboson production cross-section measurements and constraints on anomalous triple-gauge boson couplings performed by the ATLAS and CMS collaborations using proton-proton collisions produced at a centre-of-mass energy of sqrt{s} = 7 and 8 TeV at LHC. Results for all combinations of W, Z and γ gauge bosons (excluding γγ) are presented with emphasis on the new WZ and ZZ production cross sections measured by ATLAS at sqrt{s} = 8 TeV and on the new constraints on anomalous triple-gauge couplings set by CMS in the WW and Zγ modes.
Recent results of Wgamma, Zgamma and WW cross-section measurements in the electron and muon channels are reported from p-pbar collisions at sqrt(s)=1.96TeV recorded by the CDF and D0 collaborations. Total cross-sections and kinematic distributions are found to be consistent with Standard Model expectations.
Tevatron diboson measurements are reviewed, and new or recent results reported for Wgamma, Zgamma, and ZZ production in the leptonic decay modes, and for WW/WZ production in the lepton plus jets decay mode. The most stringent limits on anomalous triple gauge couplings are reported for each final state.
We present measurements of the anomalous WWgamma and WWZ trilinear gauge couplings from a combination of four diboson production and decay channels using data collected by the D0 detector at the Fermilab Tevatron Collider. These results represent the first high statistics combination of limits across different diboson production processes at the Tevatron and use data corresponding to an integrated luminosity of approximately 1 fb^-1. When respecting SU(2)_L x U(1)_Y symmetry, we measure central values and 68% C.L. allowed intervals of kappa_gamma=1.07^+0.16_-0.20, lambda =0.00^+0.05_-0.04 and …
This review article summarizes results on the production cross section measurements of electroweak boson pairs ($WW$, $WZ$, $ZZ$, $Wγ$ and $Zγ$) at the Large Hadron Collider (LHC) in $pp$ collisions at a center-of-mass energy of $\sqrt{s}=7$ \TeV. The two general-purpose detectors at the LHC, ATLAS and CMS, recorded an integrated luminosity of $5fb^{-1}$ in 2011, which offered the possibility to study the properties of diboson production to high precision. These measurements test predictions of the Standard Model (SM) in a new energy regime and are crucial for the understanding and the measure…
At the Fermilab Tevatron, the CDF and D0 detectors are being used to study diboson production in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV. We summarize recent measurements of the W$γ$, Z$γ$, and WW cross-sections and limits on WZ and ZZ production. Limits on anomalous trilinear gauge couplings are also presented.
We present the most recent cross section measurements for WW and WZ production in proton-antiproton collisions with sqrt(s) = 1.96 TeV at the Fermilab Tevatron in final states with two or three leptons, respectively, along with limits on WWZ triple gauge couplings. We also present the combined search for WW and WZ production in the lepton, neutrino, and dijet final state. Finally, we present ZZ cross section measurements in both the fully leptonic and the two lepton, two neutrino final states along with limits on anomalous couplings ZZZ and ZZgamma. All results presented are based on data coll…
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 brief survey of the results on diboson production at the Tevatron is presented. Measured cross sections for $Wγ$, $Zγ$, $WW$, and limits on WZ/ZZ are summarized.
This thesis presents the evidence, at 3.08 sigma, for the associate production of massive vector bosons (W and Z) in a final state with one lepton, MET and HF-tagged jets, measured with the complete CDF II dataset (9.4fb^-1 of data). The signals, both inclusive diboson production and WW vs WZ/ZZ separately, were extracted from the invariant mass distribution, M_inv(jet1,jet2), of single and double HF-tagged jet pairs. For single-tagged events the b quark vs c quark discrimination was obtained by using a bi-dimensional distribution M_inv(jet1,jet2) vs a flavor-serapator NN. The results, consist…
We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV; V = W,Z) where one boson decays to a hadronic final state. The data correspond to 3.5/fb of integrated luminosity collected by the CDF II detector in p-pbar collisions at a center-of-mass energy of 1.96 TeV. Event selection requires two identified jets and large transverse momentum imbalance. The analysis employs several novel techniques to suppress multijet background and reduce systematic uncertainties. We observe 1516 +/- 239(stat) +/- 144(syst) diboson candidate events and measu…
We present the first observation of WW+WZ production in the channel with an identified lepton and two jets in 2.7 fb$^{-1}$ of integrated luminosity collected with the CDF II detector in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV. The signal is separated from the large background using matrix element calculations and is observed with a significance of 5.4$σ$. The WW+WZ production cross section is measured to be $17.7 \pm 3.1$(stat)$\pm 2.4$(sys) pb, in good agreement with standard model predictions. A complimentary measurement using a fit to the dijet mass is also presented.
This note presents the prospects of searches for new heavy resonances decaying to diboson (WW) and measurements of electroweak WW/WZ production via vector boson scattering (VBS) in association with a high-mass dijet system in the $\ellνqq$ final states ($W\to\ellν$, $W/Z\to qq$). The prospects are presented for an integrated luminosity of 15 ab$^{-1}$ of proton-proton ($pp$) collisions at $\sqrt{s}=27$ TeV with an ATLAS-like detector simulated in the Delphes framework. The cross-section measurement of the electroweak $WW/WZ$ production in VBS processes is expected to reach the precision of $\s…
We show that the recently reported excess in resonant diboson production can be explained in the context of non-custodial composite Higgs models. Dibosons are generated via the s-channel exchange of massive vector bosons present in these models. We discuss the compatibility of the signal excess with other diboson experimental searches. We also discuss the tension between diboson production and other experimental tests of the model that include electroweak precision data, dilepton, dijet and top pair production and show that there is a region of parameter space in which they are all compatible …
$W$ boson pair production processes at $e^+e^-$ and $pp$ colliders have been conventionally interpreted as measurements of $WWZ$ and $WWγ$ triple gauge couplings (TGCs). Such interpretation is based on the assumption that new physics effects other than anomalous TGCs are negligible. While this "TGC dominance assumption" was well-motivated and useful at LEP2 thanks to precision electroweak constraints, it is already challenged by recent LHC data. In fact, contributions from anomalous $Z$ boson couplings that are allowed by electroweak precision data but neglected in LHC analyses, being enhanced…
This paper reports on a search for narrow resonances in diboson production in the $\ell\ell q\bar{q}$ final state using pp collision data corresponding to an integrated luminosity of 20 fb$^{-1}$ collected at $\sqrt{s}=8$ TeV with the ATLAS detector at the Large Hadron Collider. No significant excess of data events over the Standard Model expectation is observed. Upper limits at the 95% confidence level are set on the production cross section times branching ratio for Kaluza--Klein gravitons predicted by the Randall--Sundrum model and for Extended Gauge Model W' bosons. These results lead to t…
I present an overview of the measurements of the di-boson (WW, WZ, ZZ, Wγ, and Zγ) production cross sections in proton-proton collisions at \sqrt{s} = 7 TeV. The measurements are based on 36 pb^-1 and 1.1 fb^-1 of data collected with the CMS detector at the LHC in 2010 and 2011, respectively. The vector bosons W and Z are reconstructed in purely leptonic decays. The measured cross sections are compared with the Standard Model expectations calculated at next-to-leading order in perturbative QCD. Limits on anomalous triple gauge boson couplings are derived.
From the warped extra-dimensional model interpretation of the two forward-backward asymmetries observed on heavy quarks at LEP1, AFBb, and at Tevatron, AFBt, one predicts that LHC could observe, with the luminosity collected in 2011-2012, significant excesses in the diboson production for large invariant masses of the Z+W system, mZW, and, the W+W system, mWW.
A search for resonant diboson production using a data sample corresponding to 4.7 fb-1 of integrated luminosity collected by the ATLAS experiment at the Large Hadron Collider in pp collisions at 7 TeV is presented. The search for a narrow resonance in the WW or WZ mass distribution is conducted in a final state with an electron or a muon, missing transverse momentum and at least two jets. No significant excess is observed and limits are set using three benchmark models: WW resonance masses below 940 GeV and 710 GeV are excluded at 95% confidence level for spin-2 Randall-Sundrum and bulk Randal…
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, $H\rightarrowγγ$, $H\rightarrow ZZ^{*}\rightarrow 4 \ell$ and $H\rightarrow W W \rightarrow \ellν\ellν$. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of 7 TeV and 8 TeV, corresponding to an integrated luminosity of about 25 fb$^{-1}$. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Hig…
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…
Recent measurements of the associated production of two or three massive vector bosons in proton-proton collisions at the Large Hadron Collider, collected by the ATLAS detector at a centre-of-mass energy of $\sqrt{s} = 13$ TeV, are reported. The diboson analyses target the production and decay modes $WW\rightarrow eν_eμν_μ$, $WZ \rightarrow \ell^{\prime} ν\ell \ell\,(\ell = e, μ)$, $ZZ \rightarrow \ell\ellνν$, and the $4\ell$ final state. Fiducial inclusive cross sections are compared to state-of-the-art Standard Model calculations and several unfolded differential distributions are measured. …
The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb$^{-1}$. Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as $σ_\mathrm{WW} =$ 37.0 $^{+5.5}_{-5.2}$ (stat) $^{+2.7}_{-2.6}$ (syst) pb, $σ_\mathrm{WZ} =$ 6.4 $^{+2.5}_{-2.1}$ (stat) $^{+0.5}_{-0.3}$ (syst) pb, and $σ_\mathrm{ZZ…
It is here presented the diboson production cross section measured by the CMS collaboration in $pp$ collisions data at $\sqrt{s}$=7 TeV. $W γ$ and $Z γ$ results from 2010 analyses (36 pb$^{-1}$) are presented together with 2011 first measurements of $WW$, $WZ$ and $ZZ$ final states obtained using 1.1 fb$^{-1}$. Results obtained with 2010 data are also interpreted in term of anomalous triple gauge couplings.
In this contribution, I have outlined recent precision measurements of the standard model (SM) multiboson production at CMS. A study of diboson production at 5 TeV constitutes an important probe of the SM at a new energy, and the data favour NNLO predictions obtained by MATRIX. A study of WZ production at 13 TeV constitutes the most comprehensive study of WZ production to date, containing inclusive and differential cross section measurements, charge asymmetry measurements, constraints on the LHC proton parton distribution functions, and constraints on anomalous values of the WWZ trilinear gaug…
Heavy resonances decaying into a pair of fundamental particles such as $jj$, $\ell^+\ell^-$, $γγ$, and $\ellν$, are among the most common features to search for phenomena beyond the standard model (SM). Electroweak boson pair production, such as $WW$ or $ZZ$ with subsequent decays to $\ellν\ell'ν'$ and $\ell\ell jj$ respectively, is a powerful test of the spontaneously broken gauge symmetry of the SM and can be also used to search for phenomena beyond the SM. There is a wide spectrum of theoretical models predicting these kinds of resonant signatures. This note covers several searches for thes…
In the framework of effective Lagrangians with the SU(2)_L x U(1)_Y symmetry linearly realized, modifications of the couplings of the Higgs field to the electroweak gauge bosons are related to anomalous triple gauge couplings (TGCs). Here, we show that the analysis of the latest Higgs boson production data at the LHC and Tevatron give rise to strong bounds on TGCs that are complementary to those from direct TGC analysis. We present the constraints on TGCs obtained by combining all available data on direct TGC studies and on Higgs production analysis. Note added: The analysis has been updated w…
We present the matching of NLO QCD and NLO EW corrections to parton showers for vector-boson pair production at the LHC. We consider leptonic final states, including resonant and non-resonant diagrams, spin correlations and off-shell effects. Our results are obtained interfacing the Recola2-Collier one-loop provider with the POWHEG-BOX-RES framework. We discuss our implementation, we validate it at fixed order, and we show our final results matched to parton shower. A by-product of our work is also a general interface between Recola2-Collier and POWHEG-BOX-RES. This is the first time that EW a…
We consider $Z γ$ production in hadronic collisions and present the first computation of next-to-next-to-leading order accurate predictions consistently matched to parton showers (NNLO+PS). Spin correlations, interferences and off-shell effects are included by calculating the full process $pp\to\ell^+\ell^-γ$. We extend the recently developed MiNNLO$_{\rm PS}$ method to genuine $2\to 2$ hard scattering processes at the LHC, which paves the way for NNLO+PS simulations of all diboson processes. This is the first $2\to2$ NNLO+PS calculation that does not require an a-posteriori multi-differential…
The studies of the diboson production in proton-antiproton collisions at 1.96 TeV performed by CDF and D0 collaborations at the Tevatron collider are reported in this paper. The diboson events are identified exploiting both leptonic and semi-leptonic final states. The presented results use different subsamples of the statistics collected by the Tevatron up to 4.8 1/fb. Measured production cross sections are in good agreement with Standard Model predictions and the limits on the anomalous triple gauge boson couplings are competitive with the ones measured by experiments at the LEP.
We define a CP-asymmetric observable that is sensitive to CP-violating interactions in the gauge-boson sector. We illustrate the utility of this observable by studying how well the LHC can measure the coefficient of a particular dimension-six WWZ operator. We find that sensitivity at the 10^{-3} level is possible at the LHC with 100 fb^{-1} of integrated luminosity, which would greatly exceed the sensitivity achieved at LEP, and would rival or may even better the indirect sensitivities inferred from related operators constrained by electric dipole moment experiments.
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）
Recently, the ATLAS Collaboration recorded an interesting anomaly in diboson production with excesses at the diboson invariant mass around 2 TeV in boosted jets of all the $WZ$, $W^+ W^-$, and $ZZ$ channels. We offer a theoretical interpretation of the anomaly using a phenomenological right-handed model with extra $W'$ and $Z'$ bosons. Constraints from narrow total decay widths, dijet cross sections, and $W/Z + H$ production are taken into account. We also comment on a few other possibilities.
We report searches for standard model (SM) Higgs production decaying to WW(*) and continuum ZZ production in the two charged lepton and two neutrino final states. The data were collected with the CDF II detector at the Fermilab Tevatron and correspond to an integrated luminosity of 1.1^fb-1. In order to separate the processes contributing to the final state, event probabilities calculated using the leading order differential cross-sections were used to construct a likelihood ratio discriminant. The observed (median expected) 95% C.L. upper limit for sigma(H->WW^(*)) with 160 GeV/c^2 mass hypot…
Narrow resonances decaying into $WW$, $WZ$ or $ZZ$ boson pairs are searched for in 36.7 fb $^{-1}$ of proton-proton collision data at a centre-of-mass energy of $\sqrt{s}=13$ TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The diboson system is reconstructed using pairs of large-radius jets with high transverse momentum and tagged as compatible with the hadronic decay of high-momentum $W$ or $Z$ bosons, using jet mass and substructure properties. The search is sensitive to diboson resonances with masses in the range 1.2-5.0 TeV. No significant excess is obse…
This paper reports on a search for heavy resonances decaying into $WW$, $ZZ$ or $WZ$ using proton-proton collision data at a centre-of-mass energy of $\sqrt{s}=13$ TeV. The data, corresponding to an integrated luminosity of 139 $\mathrm{fb^{-1}}$, were recorded with the ATLAS detector from 2015 to 2018 at the Large Hadron Collider. The search is performed for final states in which one $W$ or $Z$ boson decays leptonically, and the other $W$ boson or $Z$ boson decays hadronically. The data are found to be described well by expected backgrounds. Upper bounds on the production cross sections of he…
The ATLAS Collaboration has reported excesses in the search for resonant diboson production with decay modes to hadronic final states at a diboson invariant mass around 2 TeV in boosted jets from $WZ$, $W^+W^-$, and $ZZ$ channels. Given potential contamination, we investigate the anomalies in leptophobic $U(1)_{\rm LP}$ models. We show that leptophobic models can be constructed in flipped $SU(5)\times U(1)_X$ models from free fermionic string constructions and Pati-Salam models from D-brane constructions. Additionally, we perform a collider phenomenological analysis to study production cross s…
Narrow resonances decaying into $WW$, $WZ$ or $ZZ$ boson pairs are searched for in 139 fb$^{-1}$ of proton-proton collision data at a centre-of-mass energy of $\sqrt{s}=13$ TeV recorded with the ATLAS detector at the Large Hadron Collider from 2015 to 2018. The diboson system is reconstructed using pairs of high transverse momentum, large-radius jets. These jets are built from a combination of calorimeter- and tracker-inputs compatible with the hadronic decay of a boosted $W$ or $Z$ boson, using jet mass and substructure properties. The search is performed for diboson resonances with masses gr…
New particles at the TeV-scale may have sizeable decay rates into boosted Higgs bosons or other heavy scalars. Here, we investigate the possibility of identifying such processes when the Higgs/scalar subsequently decays into a pair of W bosons, constituting a highly distinctive "diboson-jet." These can appear as a simple dilepton (plus MET) configuration, as a two-prong jet with an embedded lepton, or as a four-prong jet. We study jet substructure methods to discriminate these objects from their dominant backgrounds. We then demonstrate the use of these techniques in the search for a heavy spi…
The ATLAS collaboration (and also CMS) has recently reported an excess over Standard Model expectations for gauge boson pair production in the invariant mass region $1.8-2.2$ TeV. In the light of these results, we argue that such signal might be the first manifestation of the production and further decay of a heavy CP-even Higgs resulting from a type-I Two Higgs Doublet Model. We demonstrate that in the presence of colored vector-like fermions, its gluon fusion production cross-section is strongly enhanced, with the enhancement depending on the color representation of the new fermion states. O…
We study an s-channel resonance $R$ as a viable candidate to fit the diboson excess reported by ATLAS. We compute the contribution of the $\sim 2$ TeV resonance $R$ to semileptonic and leptonic final states at 13 TeV LHC. To explain the absence of an excess in semileptonic channel, we explore the possibility where the particle $R$ decays to additional light scalars $X,X$ or $X,Y$. Modified analysis strategy has been proposed to study three particle final state of the resonance decay and to identify decay channels of $X$. Associated production of $R$ with gauge bosons has been studied in detail…
The full ATLAS Run 2 data set with time-integrated luminosity of 139 fb$^{-1}$ in the diboson channels in hadronic final states is used to probe a simple model with an extended gauge sector (EGM), proposed by Altarelli et al., and often taken as a convenient benchmark by experimentalists. This model accommodates new charged $W'$ and neutral $Z'$ vector bosons with modified trilinear Standard Model gauge couplings, decaying into electroweak gauge boson pairs $WZ$ or $WW$, where $W$/$Z$ decay hadronically. Exclusion limits at the 95% C.L. on the $Z'$ and $W'$ resonance production cross section t…
Vbfnlo is a flexible parton level Monte Carlo program for the simulation of vector boson fusion (VBF), double and triple vector boson (plus jet) production in hadronic collisions at next-to-leading order (NLO) in the strong coupling constant, as well as Higgs boson plus two jet production via gluon fusion at the one-loop level. This note briefly describes the main additional features and processes that have been added in the new release -- Vbfnlo Version 2.6.0. At NLO QCD diboson production (Wγ, WZ, ZZ, Zγand γγ), same-sign W pair production via vector boson fusion and the process Wγγj have be…
We study the collider implication of a neutral resonance which decays to several diboson final states such as $W^+W^-$, $ZZ$, and $Zγ$ via a minimal set of effective operators. We consider both CP-even and CP-odd bosonic states with spin 0, 1, or 2. The production cross sections for the bosonic resonance states are obtained with the effective operators involving gluons (and quarks), and the branching fractions are obtained with the operators responsible for the interactions with electroweak gauge bosons. We demonstrate that each scenario allows for a broad parameter space which could accommoda…
Diboson resonance with mass of $1.8-2$ TeV is reported successively by CMS and ATLAS experiments in proton-proton collisions at $\sqrt{s}=8$ TeV. We investigate the potentiality of Higgs singlet as the TeV resonance. The challenges of low production cross section and high width for a fundamental scalar could be got over by three factors: (1) larger Yukawa couplings, (2) larger number of heavy quarks and (3) smaller mixing angle with standard model Higgs. We find that the required factors could be realized in the framework of two vector-like triplet quarks (VLTQs) and the resulting production c…
