Charged Gauge Bosons Research Articles

Vacuum stability in the one-loop approximation of a 331 model

In this study, we analyze the vacuum stability of the economical 331 model at the one-loop level using the renormalization group equations and a single-scale renormalization method. By integrating these equations, we determine stability conditions up to the Planck scale, incorporating constraints from recent experimental data on new Higgs-like bosons, charged scalars, and charged and neutral gauge bosons. Our analysis uncovers intriguing relations between the mass of the heaviest scalar and the masses of exotic quarks, in order to ensure stability of the model up to the Planck scale. For the 331 energy scale used in this work, 18 TeV, we find an upper bound on the heaviest quark mass of the model, which is not so distant from future LHC runs, serving as bounds to be searched. Additionally, we explore relations between the scalar couplings coming stability and perturbativity conditions. These impose unprecedented constraints on the economical 331 model.

A novel search strategy for right-handed charged gauge bosons at the Large Hadron Collider

We explore the potential of the Large Hadron Collider (LHC) in detecting a signal originating from the production of a heavy SU(2)R charged gauge boson that then decays into a top-bottom quark pair via the mediation of a right-handed neutrino, pp → WR → NRℓ → (ℓ′tb)ℓ. Such a channel, that we study in the context of the minimal Left-Right Symmetric Model, contrasts with conventional smoking-gun signatures targeted experimentally and phenomenologically in which only light quarks are involved. We propose a selection strategy aimed at extracting such a top-bottom signal and we estimate the resulting sensitivity of the LHC to the model. Our results demonstrate the potential impact of such a search and we therefore urge the experimental collaborations to carry out a similar analysis in the light of present and future data.

Search for vector-boson resonances decaying into a top quark and a bottom quark using pp collisions at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV with the ATLAS detector

A search for a new massive charged gauge boson, W′, is performed with the ATLAS detector at the LHC. The dataset used in this analysis was collected from proton-proton collisions at a centre-of-mass energy of s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV, and corresponds to an integrated luminosity of 139 fb−1. The reconstructed tb invariant mass is used to search for a W′ boson decaying into a top quark and a bottom quark. The result is interpreted in terms of a W′ boson with purely right-handed or left-handed chirality in a mass range of 0.5–6 TeV. Different values for the coupling of the W′ boson to the top and bottom quarks are considered, taking into account interference with single-top-quark production in the s-channel. No significant deviation from the background prediction is observed. The results are expressed as upper limits on the W′ → tb production cross-section times branching ratio as a function of the W′-boson mass and in the plane of the coupling vs the W′-boson mass.

Pair Production of Heavy Charged Gauge Bosons in pp Collisions at LHC

Abstract Two oppositely charged new heavy gauge boson pair production at the Large Hadron Collider (LHC), is presented in this paper. These bosons are known as W ′ boson due to the reason that it is the heavy version of Standard Model’s weak force carrier, the W boson. The production cross section and decay width in proton-proton (pp) collision at s = 8 TeV are calculated for different masses and coupling strengths of W ′ . Efficiencies for different signal regions and branching ratios for different decay channels are computed. In this study, the pair production ( W ′ + W ′ − ) is considered in emerging new physics as a result of pp collision at s = 8 TeV at the LHC with final state containing two tau (τ) leptons and two neutrinos (each W ′ decay to τ and its neutrino). The event selection efficiency similar to the CMS experiment is used for the mass of W ′ to set lower limits for different coupling strengths of W ′ and, the obtained results are presented in this work. For heavy gauge bosons, when coupling strength is similar to that of Standard Model’s W boson, the mass of W ′ below 445 GeV are excluded at a confidence level of 95%.

The SU(2)$_{D}$ lepton portals for muon g - 2, W boson mass and dark matter

We propose a novel model which extends the Standard Model (SM) by introducing a SU(2)_DSU(2)D gauge symmetry. In this model, a dark SU(2)_DSU(2)D Higgs doublet and a Higgs bi-doublet can contribute to the muon g-2 anomaly and the WW boson mass, remaining in tune with the recent experimental results. At the same time, the isospin charged gauge boson of SU(2)_DSU(2)D becomes a plausible candidate for Dark Matter(DM). We find that the resulting parameter space can fit the muon g-2, the W boson mass and the DM constraints simultaneously.

Transverse mass distribution and charge asymmetry in W boson production to third order in QCD

Charged gauge boson production at hadron colliders is a fundamental benchmark for the extraction of electroweak parameters and the understanding of the proton structure. To enable precision phenomenology for this process, we compute the third-order (N3LO) QCD corrections to the rapidity distribution and charge asymmetry in W boson production and to the transverse mass distribution of its decay products. Our results display substantial QCD corrections in kinematic regions relevant for Tevatron and LHC measurements. We compare the numerical magnitude of the N3LO corrections with uncertainties from electroweak input parameters and illustrate their potential impact on the determination of the W boson mass.

Charged-current non-standard neutrino interactions at the LHC and HL-LHC* *Supported by the National Natural Science Foundation of China (11875157, 12147214), the Natural Science Foundation of the Liaoning Scientific Committee (LJKZ0978), and the Outstanding Research Cultivation Program of Liaoning Normal University (21GDL004).

A series of new physics scenarios predict the existence of the extra charged gauge boson , which can induce charged-current (CC) non-standard neutrino interactions (NSIs). The theoretical constraints on the simplified model and further on the CC NSI parameters from partial wave unitarity and decays are considered. The sensitivity of the process to the model at the LHC and high-luminosity (HL) LHC experiments is investigated by estimating the expected constraints on ( or μ) using a Monte-Carlo (MC) simulation. We find that the interference effect plays an important role, and the LHC can strongly constrain . Compared with those at the LHC with , the expected constraints at the LHC with can be strengthened to approximately one order of magnitude.

New physics in text {b} rightarrow text {s} transitions in the MF331 model

There are two sources that help to explain the text {R}_text {K}, text {R}_{text {K}^*} anomalies in the MF331 model. The first is non-LFUV couplings of the new neutral gauge boson text {Z}^{prime } with leptons, text {g}^{text {Z}^prime }(e)ne text {g}^{text {Z}^prime }(mu ,tau ), which causes the text {R}_text {K}, text {R}_{text {K}^*} anomalies via text {Z}^prime -penguin diagrams involving newly charged gauge bosons text {X}^{pm }_{mu }, and exotic U-quarks. The second is the contribution from the box diagram only for the first generation of leptons. We show that the penguin diagrams can not explain text {R}_text {K}, text {R}_{text {K}^*} anomalies, and that the box diagram is required. The experimental constraints for text {R}_text {K} and text {R}_{text {K}^*} result in new particle mass degeneracy. The contributions of NP to the branching ratios text {Br}(text {B}_{text {s}}rightarrow mu ^+ mu ^-), text {Br}(text {b}rightarrow s gamma ) predict results that agree with the experimental limits in the allowed region of the NP scale.

SU(2)D lepton portals for the muon g−2 , W -boson mass, and dark matter

We propose a novel model for lepton flavor and dark matter based on the $SU(2)_D$ gauge symmetry and vector-like leptons in its fundamental representations. We introduce a dark $SU(2)_D$ Higgs doublet and a Higgs bi-doublet for the mass mixing between the vector-like lepton and the lepton. As a result, the seesaw lepton masses are generated and there are sizable one-loop contributions to the muon $g-2$ via the $SU(2)_D$ gauge bosons and the relatively heavy vector-like lepton, as indicated in Fermilab E989. The tree-level mass mixing between the $Z$ boson and the isospin neutral gauge boson of $SU(2)_D$ in our model accounts for the shift in the $W$ boson mass, being consistent with Tevatron CDFII. Finally, we show that the isospin charged gauge boson of $SU(2)_D$ becomes a plausible candidate for dark matter with a small mass splitting tied up to the modified $W$ boson mass, and there is a viable parameter space where the favored corrections to the muon $g-2$ and the $W$ boson mass and the dark matter constraints are simultaneously fulfilled.

Unraveling the left-right mixing using 0νββ decay and collider probes

In the context of the minimal left-right symmetric model, we study the interplay between current and future neutrinoless double beta ($0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$) decay experiments, long-lived particle searches at the LHC main detectors ATLAS/CMS, and the proposed far detector MATHUSLA. The heavy Majorana neutrino can be produced in association with an electron from the decay of $W$ boson for a nonzero left-right mixing and subsequently decays into another electron with the same charge and jets. Owing to the suppression of large right-handed charged gauge boson ${W}_{R}$ mass, the heavy neutrinos could be long-lived. We show that long-lived particle (LLP) searches for heavy Majorana neutrinos in the same-sign dilepton channel at the LHC can be used to extend ${W}_{R}$ boson mass reach relative to the reach of the Keung-Senjanovic (KS) process. Finally, we show that sensitivities of LLP searches at the high-luminosity LHC with main detectors ATLAS/CMS are competitive with those of future $0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ decay searches.

Testing left-right symmetry with an inverse seesaw mechanism at the LHC

In the left-right symmetric models, a heavy charged gauge boson ${W}^{\ensuremath{'}}$ can decay to a lepton and a right-handed neutrino (RHN). If the neutrino masses are generated through the standard type-I seesaw mechanism, the Yukawa couplings controlling two-body decays of the RHN become very small. As a result, the RHN decays to another lepton and a pair of jets via an off-shell ${W}^{\ensuremath{'}}$. This is the basis of the Keung-Senjanovi\ifmmode \acute{c}\else \'{c}\fi{} (KS) process, which was originally proposed as a probe of lepton number violation at the LHC. However, if a different mechanism like the inverse seesaw generates the neutrino masses, a TeV-scale RHN can have large Yukawa couplings and hence dominantly decay to a lepton and a $W$ boson, leading to a kinematically different process from the KS one. We investigate the prospect of this unexplored process as a probe of the inverse seesaw mechanism in the left-right symmetric models at the High Luminosity LHC (HL-LHC). Our signal arises from the Drell-Yan production of a ${W}^{\ensuremath{'}}$ and leads to two high-${p}_{T}$ same-flavour-opposite-sign leptons and a boosted $W$-like fatjet in the final state. We find that a sequential ${W}^{\ensuremath{'}}$ with mass up to $\ensuremath{\sim}6\text{ }\text{ }\mathrm{TeV}$ along with a TeV-scale RHN can be discovered at the HL-LHC.

Phenomenology of an E6 inspired extension of the Standard Model: Higgs sector

We investigate a variant of the left-right symmetric model based on the $SU(3{)}_{C}\ensuremath{\bigotimes}SU(2{)}_{L}\ensuremath{\bigotimes}U(1{)}_{L}\ensuremath{\bigotimes}SU(2{)}_{R}\ensuremath{\bigotimes}U(1{)}_{R}$ gauge group (32121). Spontaneously breaking of 32121 down to the Standard Model (SM) gauge group requires a bidoublet under $SU(2{)}_{L}\ensuremath{\bigotimes}SU(2{)}_{R}$, a right-handed doublet scalar under $SU(2{)}_{R}$, along with a $SU(2)$ singlet scalar boson. Symmetry breaking leads to several neutral and charged massive gauge bosons apart from the SM $W$ and $Z$. The Large Hadron Collider (LHC) results for the search of heavy gauge bosons can be used to constrain the vacuum expectation values responsible for giving masses to these extra heavy gauge bosons. The physical spectrum of the scalar bosons contains several neutral $CP$-even and $CP$-odd states and a couple of charged scalars apart from the SM-like Higgs boson. We have put constraints on the masses of some of these scalars from the existing LHC data. The possible decay rates and production cross sections of these scalars have been investigated in some detail. Production cross sections for some of the scalars look promising at the 14 and 27 TeV runs of the LHC with the high luminosity option. We keep, in our model, all the fermions present in the 27-dimensional fundamental representation of ${E}_{6}$. Mass limit of one such exotic lepton has also been derived from present LHC data. It is noted that some of these neutral exotic lepton or neutral scalar bosons of this model can serve the purpose of cold dark matter.

Enhancing the Large Hadron Collider sensitivity to charged and neutral broad resonances of new gauge sectors

In scenarios beyond the Standard Model (BSM) characterised by charged (W′) or neutral (Z′) massive gauge bosons with large width, resonant mass searches are not very effective, so that one has to exploit the tails of the mass distributions measured at the Large Hadron Collider (LHC). In this case, the LHC sensitivity to new physics signals is influenced significantly by systematic uncertainties associated with the Parton Distribution Functions (PDF), particularly in the valence quark sector relevant for the multi-TeV mass region. As a BSM framework featuring such conditions, we consider the 4-Dimensional Composite Higgs Model (4DCHM), in which multiple W′ and Z′ broad resonances are present, with strongly correlated properties. By using the QCD tool xFitter, we study the implications on W′ and Z′ searches in Drell-Yan (DY) lepton decay channels that follow from the reduction of PDF uncertainties obtained through combining high-statistics precision measurements of DY lepton-charge and forward-backward asymmetries. We find that the sensitivity to the BSM states is greatly increased with respect to the case of base PDF sets, thereby enabling one to set more stringent limits on (or indeed discover) such new particles, both independently and in correlated searches.

Decay Width of 3-3-1 Model Charged Higgs and Gauge Bosons

The total decay widths of the charged Higgs (H±2) and gauge bosons (V±) have been calculated in the version of the 3-3-1 Model with heavy leptons. In each case, we analyze the decay rates and determine the most likely channels to occur in order to identify the most relevant final events.

Studies on dimension-eight genuine Quartic Boson Coupling operators

Vector Boson Scattering (VBS) processes provide a great source of information on the structure of the Quartic Gauge Boson Couplings (QGCs). The Standard Model allows self interactions of the charged vector gauge bosons, although vertices with neutral-only bosons are forbidden. In this paper we use Monte Carlo samples containing VBS events with two Z-bosons in association with two jets, and we present preliminary studies for the setting of constraints on anomalous quartic couplings. In these studies we investigate typical kinematic variables and we classify them according to their sensitivity to aQGC effects. Finally, we evaluate the cross-section enhancement by each one of the dimension-eight QGC operators in the ZZjj channel.

Probing new physics in class-I B-meson decays into heavy-light final states

With updated experimental data and improved theoretical calculations, several significant deviations are being observed between the Standard Model predictions and the experimental measurements of the branching ratios of {overline{B}}_{(s)}^0to {D}_{(s)}^{left(ast right)+}{L}^{-} decays, where L is a light meson from the set {π, ρ, K(∗)}. Especially for the two channels {overline{B}}^0to {D}^{+}{K}^{-} and {overline{B}}_s^0to {D}_s^{+}{pi}^{-} , both of which are free of the weak annihilation contribution, the deviations observed can even reach 4–5σ. Here we exploit possible new-physics effects in these class-I non-leptonic B-meson decays within the framework of QCD factorization. Firstly, we perform a model-independent analysis of the effects from twenty linearly independent four-quark operators that can contribute, either directly or through operator mixing, to the quark-level b → coverline{u}d(s) transitions. It is found that, under the combined constraints from the current experimental data, the deviations observed could be well explained at the 1σ level by the new-physics four-quark operators with γμ(1 − γ5) ⨂ γμ(1 − γ5) structure, and also at the 2σ level by the operators with (1 + γ5) ⨂ (1 − γ5) and (1 + γ5) ⨂ (1 + γ5) structures. However, the new-physics four-quark operators with other Dirac structures fail to provide a consistent interpretation, even at the 2σ level. Then, as two specific examples of model-dependent considerations, we discuss the case where the new-physics four-quark operators are generated by either a colorless charged gauge boson or a colorless charged scalar, with their masses fixed both at the 1 TeV. Constraints on the effective coefficients describing the couplings of these mediators to the relevant quarks are obtained by fitting to the current experimental data.

Top-flavor scheme in the context of W′ searches at LHC

Many extensions of the Standard Model predict the existence of new charged or neutral gauge bosons, with a wide variety of phenomenological implications depending on the model adopted. The search for such particles is extensively carried through at the Large Hadron Collider (LHC), and it is therefore of crucial importance to have for each proposed scenario quantitative predictions that can be matched to experiments. In this work we focus on the implications of one of these models, the TopFlavor Model, proposing a charged $\text{W}^\prime$ boson that has preferential couplings to the third generation fermions. We compare such predictions to the ones from the so called Sequential Standard Model (SSM), that is used as benchmark, being one of the simplest and most commonly considered models for searches at the LHC. We identify the parameter space still open for searches at the LHC, and in particular we show that the cross section for the processes $pp \to \text{W}^\prime \to \tau \nu$ and $pp \to \text{W}^\prime \to tb$ can be up to two orders of magnitude smaller with respect to the SSM, depending on the free parameters of the model, like the particle mass and its width. This study makes the case for further searches at the LHC, and shows how a complete and systematic model independent analysis of $\text{W}^\prime$ boson phenomenology at colliders is essential to provide guidance for future searches.

Precise predictions for WH+jet production at the LHC

We present precise predictions for the production of a Higgs boson in association with a hadronic jet and a W boson at hadron colliders. The behaviour of QCD corrections are studied for fiducial cross sections and distributions of the charged gauge boson and jet-related observables. The inclusive process (at least one resolved jet) and the exclusive process (exactly one resolved jet) are contrasted and discussed. The inclusion of QCD corrections up to O(αs3) leads to a clear stabilisation of the predictions and contributes substantially to a reduction of remaining theoretical uncertainties.

The CP violation and scalar dark matter in a 331 model

The 331 model with right-handed neutrinos is reassessed to investigate the CP violation in the quark sector. After the spontaneous symmetry breaking, the masses and physical fields of the particle content are obtained. The fermions content of the 331 model is enlarged to include exotic quarks with known electric charge and with masses defined at the TeV scale. The existence of these exotic quarks induces extra CP violations via couplings with quarks of the Standard Model mediated by charged gauge boson with mass fixed at the TeV scale. An extra discrete [Formula: see text] symmetry is introduced in the 331 model to get a stable scalar field that can be a candidate to the dark matter content. The new scalar field interacts at the tree level with the [Formula: see text] gauge boson that works as a dark matter portal. The relic density associated with the scalar field is calculated to yield the solution mass that satisfies the observed dark matter. The region allowed on the parameter space of the dark matter mass versus [Formula: see text] mass is obtained to include the bounds of PANDAX2017, XENON1T(2t.y) and LUX experiments.

Prospect of the search for $${\mathrm {W}}^{\prime }$$ in vector boson fusion at the high-luminosity large hadron collider

A search for a new heavy charged gauge boson $${\mathrm {W}}^{\prime }$$ produced via a vector boson fusion process with two hard jets in pp collisions in the high-luminosity Large hadron collider (HL-LHC) environment is presented. The HL-LHC will increase the peak instantaneous luminosity to $$7.5 \times 10^{34}~{\mathrm {cm}}^{-2}~{\mathrm {s}}^{-1}$$ and the center of mass energy of 14 TeV to collect integrated luminosities up to 3 $${\mathrm {ab}}^{-1}$$ , which will significantly improve sensitivity for the observation of new heavy particles via rare processes. In this paper, to investigate the signal sensitivity for a $${\mathrm {W}}^{\prime }$$ we use the heavy vector triplet model, in the context of a simplified phenomenological approach, under Monte-Carlo simulations. The search targets events with one energetic electron and large missing transverse momentum, as well as two jets with a large separation in pseudorapidity. The expected upper limit for the mass of $${\mathrm {W}}^{\prime }$$ and exclusion limit contour on coupling parameters are presented at the 95% confidence level for an integrated luminosity of 3 $${\mathrm {ab}}^{-1}$$ .