Charged Bosons Research Articles

Improved bounds on W−W′ mixing with ATLAS resonant WZ production data at the LHC at s=13 TeV

New charged vector bosons $W'$ decaying into gauge boson pairs $WZ$ are predicted in many scenarios of new physics, including models with an extended gauge sector (EGM). Due to the large variety of models (other unification groups, models with Supersymmetry, Little Higgs Models, Extra Dimensions) the more general EGM approach is here considered. For what concerns $W'$-production, these models are parametrised by two parameters, the $W^\prime$ mass $M_{W^\prime}$ and the $W$-$W^\prime$ mixing parameter $\xi$. The diboson $WZ$ production allows to place stringent constraints on this mixing angle and the $W'$ mass, which we determine and present for the first time by using data from $pp$ collisions at $\sqrt{s}=13$ TeV recorded by the ATLAS detector at the CERN LHC, with integrated luminosity of 36.1 fb$^{-1}$. By comparing the experimental limits to the theoretical predictions for the total cross section of $W'$ resonant production and its subsequent decay into $WZ$ pairs, we show that the derived constraints on the mixing angle for the benchmark model are rather small, between $10^{-4}$ and $10^{-3}$, i.e., greatly improved with respect to those derived from the global analysis of electroweak data which yield $\xi\sim 10^{-2}$. We combine the limits derived from $WZ$ production data with those obtained from the $W'\to e\nu$ process in order to significantly extend the exclusion region in the $M_{W'}$-$\xi$ parameter plane and obtain the most stringent exclusion limits to date. We present the combined allowed parameter space for the EGM $W'$ boson after incorporating indirect constraints from low energy electroweak data, direct search constraints from Tevatron and from the LHC Run I with 7 and 8 TeV as well as at Run II with 13 TeV data.

Effect of the weak interaction on the in situ radii of condensate boson atoms in one or two-dimensional deep optical lattices

In this letter we suggest a theoretical model to investigate the weak interaction dependence of the in situ radii of condensate boson atoms in a combined harmonic with one or two-dimensional deep optical lattice. The semiclassical approximation is employed to calculate the above mentioned parameters. The calculated results showed that the in situ radii depends crucially on the interatomic interaction. Our results can be extended to investigate the moment of inertia of condensate boson atoms in combined harmonic-optical potential as well as superfluidity nature of synthetically charged boson atoms in combined potential.

Vector SIMP dark matter with approximate custodial symmetry

We consider a novel scenario for Vector Strongly Interacting Massive Particle (VSIMP) dark matter with local SU(2)X × U(1)Z′ symmetry in the dark sector. Similarly to the Standard Model (SM), after the dark symmetry is broken spontaneously by the VEVs of dark Higgs fields, the approximate custodial symmetry determines comparable but split masses for SU(2)X gauge bosons. In this model, we show that the U(1)Z′ -charged gauge boson of SU(2)X (X±) becomes a natural candidate for SIMP dark matter, annihilating through 3 → 2 or forbidden 2 → 2 annihilations due to gauge self-interactions. On the other hand, the U(1)Z′ -neutral gauge boson of SU(2)X achieves the kinetic equilibrium of dark matter through a gauge kinetic mixing between U(1)Z′ and SM hypercharge. We present the parameter space for the correct relic density in our model and discuss in detail the current constraints and projections from colliders and direct detection experiments.

Phase diagrams of charged compact boson stars

Compact boson stars, whose scalar field vanishes identically in the exterior region, arise in a theory involving a massless complex scalar field with a conical potential, when coupled to gravity. Their charged compact generalizations, obtained in the presence of a U(1) gauge field, exhibit further interesting features. On the one hand, charged compact boson shells can arise, whose scalar field vanishes also in the central region, while on the other hand, the domain of existence of charged compact boson stars exhibits bifurcation points. First 2D phase diagrams have been studied before. Here we extend these earlier studies to a larger range of the variables and study additional phase diagrams. We then extend these studies to obtain 3D phase diagrams and present these with a detailed discussion of their various regions with respect to the bifurcation points and argue, that there is an infinite series of such bifurcation points. Thus the theory is seen to contain rich physics in a particular domain of the phase diagrams. We also discuss the dependence of the fields on the dimensionless radial coordinate for some representative points of the phase trajectories in the phase diagrams of the theory.

Phenomenological study of texture zeros in lepton mass matrices of minimal left-right symmetric model

We consider the possibility of texture zeros in lepton mass matrices of the minimal left-right symmetric model (LRSM) where light neutrino mass arises from a combination of type I and type II seesaw mechanisms. Based on the allowed texture zeros in light neutrino mass matrix from neutrino and cosmology data, we make a list of all possible allowed and disallowed texture zeros in Dirac and heavy neutrino mass matrices which appear in type I and type II seesaw terms of LRSM. For the numerical analysis we consider those cases with maximum possible texture zeros in light neutrino mass matrix Mν, Dirac neutrino mass matrix MD, heavy neutrino mass matrix MRR while keeping the determinant of MRR non-vanishing, in order to use the standard type I seesaw formula. The possibility of maximum zeros reduces the free parameters of the model making it more predictive. We then compute the new physics contributions to rare decay processes like neutrinoless double beta decay, charged lepton flavour violation. We find that even for a conservative lower limit on left-right symmetry scale corresponding to heavy charged gauge boson mass 4.5 TeV, in agreement with collider bounds, for right-handed neutrino masses above 1 GeV, the new physics contributions to these rare decay processes can saturate the corresponding experimental bound.

Structure of rotating charged boson stars

In this work we present full sets of solutions for rotating charged boson stars with different coupling values. By adopting local comoving coordinates, we are able to find expressions for the effective hydrodynamic quantities of the fluids as seen by this class of observers. We show that not only is the energy density non zero at the center, for the uncharged case it has a local maximum at the core from which it decreases until the point of local minimum where its variation is discontinuous. For the first time, it is reported how rotating boson stars, charged and uncharged, are completely anisotropic fluids featuring three different pressures. Furthermore, the character of the electromagnetic fields is analyzed.

Effect of Quantum Gravity on the Stability of Black Holes

We investigate the massive vector field equation with the WKB approximation. The tunneling mechanism of charged bosons from the gauged super-gravity black hole is observed. It is shown that the appropriate radiation consistent with black holes can be obtained in general under the condition that back reaction of the emitted charged particle with self-gravitational interaction is neglected. The computed temperatures are dependant on the geometry of black hole and quantum gravity. We also explore the corrections to the charged bosons by analyzing tunneling probability, the emission radiation by taking quantum gravity into consideration and the conservation of charge and energy. Furthermore, we study the quantum gravity effect on radiation and discuss the instability and stability of black hole.

Fine Effects in the Temperature Dependence of the Thermal Conductivity of Y-123 Cuprates in a “Weak” Pseudogap State

Quasiregular anomalies of the thermal conductivity k of the YBa2Cu3O7 − x hole high-temperature superconductor in a pseudogap state, as well as a “giant” anomaly near TC, have been detected for the first time. The temperature anomalies of the carrier density (nh) in YBa2Cu3O7 − x have been revealed and their correlation with k anomalies has been established. It has been shown that nh(k) anomalies of the pseudogap state are due to the step-by-step pairing of charge carriers into positively charged bosons. The correlation of nh(k) anomalies near TC with the topological conversion of a part of the Fermi surface, on one hand, and with the structure anomaly, on the other hand, has been established.

Note on monopole operators in Chern-Simons-matter theories

Monopole operators in Chern-Simons theories with charged matter have been studied using the state-operator map in CFTs, as states on ℝ × S2 with background magnetic flux on S2. Gauge invariance requires a dressing with matter modes which provides non-zero spin to the monopoles. In this note we propose a description of the monopole operators directly on ℝ3, as a singular behavior of the gauge and matter fields in the vicinity of the insertion point, with a dressing. We study abelian theories with a charged boson or a charged fermion. We extend the discussion to abelian supersymmetric Chern-Simons-matter theories and describe the BPS monopoles, which have spin and preserve a single supercharge. We match our results against the prediction from the superconformal index.

Search for heavy neutrinos and third-generation leptoquarks in hadronic states of two \u03c4 leptons and two jets in proton-proton collisions at sqrt{s}=13 TeV

A search for new particles has been conducted using events with two high transverse momentum τ leptons that decay hadronically and at least two energetic jets. The analysis is performed using data from proton-proton collisions at sqrt{s}=13 TeV, collected by the CMS experiment at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb−1. The observed data are consistent with standard model expectations. The results are interpreted in the context of two physics models. The first model involves right-handed charged bosons, WR, that decay to heavy right-handed Majorana neutrinos, Nℓ (ℓ = e, μ, τ), arising in a left-right symmetric extension of the standard model. The model considers that Ne and Nμ are too heavy to be detected at the LHC. Assuming that the Nτ mass is half of the WR mass, masses of the WR boson below 3.50 TeV are excluded at 95% confidence level. Exclusion limits are also presented considering different scenarios for the mass ratio between Nτ and WR, as a function of WR mass. In the second model, pair production of third-generation scalar leptoquarks that decay into ττbb is considered, resulting in an observed exclusion region with leptoquark masses below 1.02 TeV, assuming a 100% branching fraction for the leptoquark decay to a τ lepton and a bottom quark. These results represent the most stringent limits to date on these models.

The hardest TC self-energy behavior and radiative corrections in a 331-TC model

The solution of the phenomenological problems of technicolor (TC) models may reside in the different dynamical behaviors of the technifermions self-energy appearing in walking (or quasi-conformal) theories. Motivated by recent results, where it is shown how the boundary conditions (BC) of the anharmonic oscillator representation of the Schwinger–Dyson gap equation (SDE) to [Formula: see text] are directly related with the mass anomalous dimensions, and different BC cause a change in the ultraviolet asymptotic behavior of the self-energies, in this paper, we verify that it is possible to have a hard technifermion self-energy in TC models originated through radiative corrections coming from the interactions mediated by the new massive neutral and charged gauge bosons, [Formula: see text] and [Formula: see text] in the context of a 331-TC model.

Search for doubly charged scalar bosons decaying into same-sign W boson pairs with the ATLAS detector

A search for doubly charged scalar bosons decaying into W boson pairs is presented. It uses a data sample from proton–proton collisions corresponding to an integrated luminosity of 36.1 fb^mathrm {-1} collected by the ATLAS detector at the LHC at a centre-of-mass energy of 13 TeV in 2015 and 2016. This search is guided by a model that includes an extension of the Higgs sector through a scalar triplet, leading to a rich phenomenology that includes doubly charged scalar bosons H^{pm pm }. Those bosons are produced in pairs in proton–proton collisions and decay predominantly into electroweak gauge bosons H^{pm pm }rightarrow W^{pm } W^{pm }. Experimental signatures with several leptons, missing transverse energy and jets are explored. No significant deviations from the Standard Model predictions are found. The parameter space of the benchmark model is excluded at 95% confidence level for H^{pm pm } bosons with masses between 200 and 220 GeV.

Derivation of spontaneously broken gauge symmetry from the consistency of effective field theory II: Scalar field self-interactions and the electromagnetic interaction

We extend our study of deriving the local gauge invariance with spontaneous symmetry breaking in the context of an effective field theory by considering self-interactions of the scalar field and inclusion of the electromagnetic interaction. By analyzing renormalizability and the scale separation conditions of three-, four- and five-point vertex functions of the scalar field, we fix the two couplings of the scalar field self-interactions of the leading order Lagrangian. Next we add the electromagnetic interaction and derive conditions relating the magnetic moment of the charged vector boson to its charge and the masses of the charged and neutral massive vector bosons to each other and the two independent couplings of the theory. We obtain the bosonic part of the Lagrangian of the electroweak Standard Model as a unique solution to the conditions imposed by the self-consistency conditions of the considered effective field theory.

Improved constraints on the mixing and mass of Z′ bosons from resonant diboson searches at the LHC at s=13 TeV and predictions for Run II

New neutral vector bosons $Z'$ decaying to charged gauge boson pairs $W^+W^-$ are predicted in many scenarios of new physics, including models with an extended gauge sector such as $E_6$, left-right symmetric $Z^\prime_{\rm LRS}$ and the sequential standard model $Z'_{\rm SSM}$. For these benchmark models we calculate and present theoretical expectations for different values of the $Z^\prime$ mass $M_2$ and mixing parameter $\xi$. Our results are based on the narrow width approximation which allows to make a convenient comparison of experiment to theoretical benchmark models. The diboson production allows to place stringent constraints on the $Z$-$Z'$ mixing angle and the $Z'$ mass, which we determine by using data from $pp$ collisions at $\sqrt{s}=13$ TeV recorded by the ATLAS detector at the CERN LHC, with integrated luminosity of $\sim$ 36 fb$^{-1}$. By comparing the experimental limits to the theoretical predictions for the total cross section of $Z'$ resonant production and its subsequent decay into $W^+W^-$ pairs, we show that the derived constraints on the mixing angle for the benchmark models are of the order of a few $\times 10^{-4}$, i.e., greatly improved with respect to those derived from the global analysis of electroweak data. We combine the limits derived from diboson production data with those obtained from the Drell--Yan process in order to significantly extend the exclusion region in the $M_{2}$-$\xi$ parameter plane. Also, we demonstrate that further improvement on the constraining of this mixing can be achieved through analysis of the full set of Run~II data.

Search for vector-boson resonances decaying to a top quark and bottom quark in the lepton plus jets final state in pp collisions at [formula omitted] with the ATLAS detector

A search for new charged massive gauge bosons, W′, is performed with the ATLAS detector at the LHC. Data were collected in proton–proton collisions at a center-of-mass energy of s=13 TeV and correspond to an integrated luminosity of 36.1 fb−1. This analysis searches for W′ bosons in the W′→tb¯ decay channel in final states with an electron or muon plus jets. The search covers resonance masses between 0.5 and 5.0 TeV and considers right-handed W′ bosons. No significant deviation from the Standard Model (SM) expectation is observed and upper limits are set on the W′→tb¯ cross section times branching ratio and the W′ boson effective couplings as a function of the W′ boson mass. For right-handed W′ bosons with coupling to the SM particles equal to the SM weak coupling constant, masses below 3.15 TeV are excluded at the 95% confidence level. This search is also combined with a previously published ATLAS result for W′→tb¯ in the fully hadronic final state. Using the combined searches, right-handed W′ bosons with masses below 3.25 TeV are excluded at the 95% confidence level.

Quantum gravity effect on the Hawking radiation of charged rotating BTZ black hole

In this study, the quantum gravity effect on the tunnelling radiation of charged massive spin-0 scalar particle from 2+1 dimensional charged rotating Banados-Teitelboim-Zanelli (BTZ) black hole is looked into by using the Hamilton-Jacobi approach. For this, we calculate the modified Hawking temperature of the black hole by using the modified Klein-Gordon equation based on the Generalized Uncertainty Principle (GUP), and we noticed that the modified Hawking temperature of the black hole depends not only on the black hole properties, but also on the angular momentum, energy, charge and mass of the tunnelling scalar particle. Using the modified Hawking temperature, we discussed the stability of the black hole in the context of the modified heat capacity, and observed that it might undergo both first and second-type phase transitions in the presence of the quantum gravity effect, but just a first-type transition in the absence of the quantum gravity effect. Furthermore, we investigated the modified Hawking temperature of the black hole by using the tunnelling processes of the charged massive Dirac and vector boson particles. We observed that scalar, Dirac and vector particles are tunnelled from the black hole completely differently from each other in the presence of the quantum gravity effect.

On The Fractional Fundamental Boson

Our vision is to theoretically establish a fractional charged elementary vector boson of spin unity and also an equation to compute the mass of elementary but charged weak gauge boson.

Interaction effect on the magnetic properties of synthetically charged boson atoms in 2D deep optical lattice

In this paper, the interaction effect on the magnetic properties of synthetically charged boson atoms in 2D deep optical lattice are investigated. The analysis was made using the methodology of Hartree-Fock approximation for which an integral over phase-space is performed to calculate the accurate grand canonical thermo-magnetic potential. Subsequently, the grand potential is used to determine magnetic susceptibility, magnetization as well as the heat capacity at fixed magnetic field. Our approach provides a new approach to use optical potential to reach highly strong synthetic magnetic field. The outcome results provide a theoretical viewpoint for the experiment carried out by Bloch and his coworker.

It\u2019s all right(-handed neutrinos): a new W\u2032 model for the {R}_{D^{{}_{left(ast right)}}} anomaly

The measured B-meson semi-leptonic branching ratios RD and {R}_{D^{*}} have long-standing deviations between theory and experiment. We introduce a model which explains both anomalies through a single interaction by introducing a right-handed neutrino as the missing energy particle. This interaction is mediated by a heavy charged vector boson (W′) which couples only to right-handed quarks and leptons of the Standard Model through the mixing of these particles with new vector-like fermions. Previous W′ models for the {R}_{D^{left(*right)}} anomaly were strongly constrained from flavor changing neutral currents and direct collider searches for Z′ → τ τ resonances. We show that relying on right-handed fermion mixing enables us to avoid these constraints, as well as other severe bounds from electroweak precision tests and neutrino mixing.

Chromomagnetic and chromoelectric dipole moments of the top quark in the fourth-generation THDM

The chromomagnetic dipole moment (CMDM) and chromoelectric dipole moment (CEDM) of the top quark are calculated at the one-loop level in the framework of the two-Higgs doublet model with four fermion generations (4GTHDM), which is still consistent with experimental data and apart from new scalar bosons (${H}^{0}$, ${A}^{0}$, and ${H}^{\ifmmode\pm\else\textpm\fi{}}$) and quarks (${b}^{\ensuremath{'}}$ and ${t}^{\ensuremath{'}}$) predicts new sources of $CP$ violation via the extended $4\ifmmode\times\else\texttimes\fi{}4$ CKM matrix. Analytical expressions for the CMDM and CEDM of a quark are presented both in terms of Feynman parameter integrals, which are explicitly integrated, and Passarino-Veltman scalar functions, with the main contributions arising from loops carrying the scalar bosons accompanied by the third- and fourth-generation quarks. The current bounds on the parameter space of the 4GTHDM are discussed and a region still consistent with the LHC data on the 125 GeV Higgs boson and the oblique parameters is identified. It is found that the top quark CMDM, which is induced by all the scalar bosons, can reach values of the order of ${10}^{\ensuremath{-}2}--{10}^{\ensuremath{-}1}$. As for the top quark CEDM, it only receives contributions from the charged scalar boson and can reach values of the order of ${10}^{\ensuremath{-}20}--{10}^{\ensuremath{-}19}\text{ }\text{ }\mathrm{ecm}$ for relatively light ${m}_{{H}^{\ifmmode\pm\else\textpm\fi{}}}$ and heavy ${m}_{{b}^{\ensuremath{'}}}$, with the dominant contribution arising from the $b$ quark. The CEDM would be the most interesting prediction of this model as it can be larger than the value predicted by the usual THDMs by one order of magnitude.