Search

This paper examines the Standard Model under the strong–electroweak symmetry group SUS(3)×UEW(2) subject to the Lie algebra condition 픲EW(2)≇̸픰픲I(2)⊕픲Y(1). Physically, the condition ensures that all electroweak gauge bosons interact with each other prior to symmetry breaking — as one might expect from U(2) invariance. This represents a crucial shift in the identification of physical gauge bosons: Unlike the Standard Model which posits a change of Lie algebra basis induced by spontaneous symmetry breaking, here the basis is unaltered and A, Z0, W± represent the physical bosons both before and after spontaneous symmetry breaking.Our choice of 픲EW(2) requires some modification of the matter field representation of the Standard Model. The group UEW(2) admits two pertinent defining representations, 2 and its U(2)-conjugate 2c, related by a large gauge transformation. Accordingly, the product group structure calls for strong–electroweak degrees of freedom in the (3,2) and the (3,2c) of SUS(3)×UEW(2) that possess integer electric charge just like leptons. These degrees of freedom play the role of quarks, and they lead to a modified Lagrangian that nevertheless reproduces transition rates and cross-sections equivalent to the Standard Model. In particular, they reproduce the fractional electric charge of quark currents.The close resemblance between quark and lepton electroweak doublets in this picture suggests a mechanism for a speculative phase transition between quarks and leptons that stems from the product structure of the symmetry group. Our hypothesis is that the strong and electroweak bosons see each other as a source of decoherence. In effect, lepton representations get identified with the SU(3)-trace-reduced quark representations. This mechanism allows for possible extensions of the Standard Model that do not require large inclusive multiplets of matter fields and might explain the Higgs as a pseudo Nambu–Goldstone boson. [ABSTRACT FROM AUTHOR]

Anomaly-free U (1) extensions of the standard model (SM) predict a new neutral gauge boson Z ′ . When Z ′ obtains its mass from the spontaneous breaking of the new U (1) symmetry by a new complex scalar field, the model also predicts a second real scalar s, and the search for the new scalar and the search for the new gauge boson become intertwined. We present the computation of production cross sections and decay widths of such a scalar s in models with a light Z ′ boson when the decay h → Z ′ Z ′ may have a sizeable branching ratio. We show how the Higgs signal strength measurement in this channel can provide stricter exclusion bounds on the parameters of the model than those obtained from the total signal strength for Higgs boson production. [ABSTRACT FROM AUTHOR]

In this paper, we show that loop-induced processes involving new physics particles can readily satisfy Landau Equation and trigger triangular singularities at high-energy colliders, leading to fully visible Standard Model final states. In addition, a t-channel triangular singularity can also occur during particle scattering processes that may extend to low momentum exchange. We discuss several typical scenarios in supersymmetric and extended Higgs models, and three types of final-state kinematic features at the collider. Four-particle vertices in new physics can play a significant role in high energy diagrams. We identify an "everything on shell" triangular singularity diagram only involving bosonic couplings, which has the potential to completely avoid large virtuality suppression. We further show that such a virtuality-free diagram is missing in the Standard Model at electroweak scale, and it becomes available in new physics models. [ABSTRACT FROM AUTHOR]

In light of the recent result published by the Fermilab Muon (g − 2) experiment, we investigate a simple model that includes particles of fractional electric charges: a color-singlet fermion and a scalar with charges 2 ∕ 3 e and 1 ∕ 3 e , respectively. The impact of these particles on the muon anomalous magnetic moment is examined, particularly the restrictions on their Yukawa couplings with the light leptons. Given that lepton flavor violation processes impose stringent constraints on certain scenarios beyond the Standard Model, we evaluate the one-loop contribution of the new particles to (g − 2) in order to identify regions in the parameter space consistent with the Fermilab results and compatible with the current and projected limits on the branching ratio Br (μ → e γ). Taking into account the current lower bound for the masses of fractionary charged particles, which is around 634 GeV, we show that the mass of the scalar particle with fractional charge must exceed 1 TeV. In particular, we present some estimatives for double production of the color-singlet fermion at the 14 TeV LHC. Finally, we also study the validity of our model in light of the QCD lattice results on the muon (g − 2). [ABSTRACT FROM AUTHOR]

Without adhering to any specific model, we have presented 4 × 4 quark mixing matrix as an extension of the 3 × 3 Particle Data Group (PDG) parametrization of the Cabibbo–Kobayashi–Maskawa (CKM) matrix Using unitarity constraints as well as the hierarchy among the elements of the 3 × 3 CKM matrix, we have found the hierarchy among the fourth row and fourth column elements of the 4 × 4 quark mixing matrix. Further, for the fourth generation case, we have explicitly found the nine independent rephasing invariant parameters J 4 × 4 . Also, using phenomenological estimates of the fourth row and fourth column elements, we have numerically evaluated these nine parameters. [ABSTRACT FROM AUTHOR]

For well over half a century, precision studies of neutron and nuclear β decays have been at the forefront of searches for exotic electroweak physics. Recent advances in nuclear ab initio theory and the widespread use of effective field theories mean that the modern understanding of β decay is going through a transitional phase. This has been propelled by current tensions in the global dataset leading to renewed scrutiny of the theoretical ingredients. In parallel, novel techniques and methods are being investigated that can sidestep many traditional systematic uncertainties and require a diverse palette of skills and collaboration with material science and condensed matter physics. This review highlights the current opportunities and open questions to facilitate the transition to a more modern understanding of β decay. [ABSTRACT FROM AUTHOR]

In this write-up, we provide an overview of the existing theoretical framework concerning rare kaon decays, with a particular emphasis on flavour-changing neutral current processes. These decays offer crucial indirect pathways for investigating short-distance new physics. Our discussion will encompass standard model predictions for relevant observables, alongside an assessment of their capacity to probe new physics through a comparison with experimental data. [ABSTRACT FROM AUTHOR]

The quartification model is an S U (3) 4 extension with a bi-fundamental fermion sector of the well-known S U (3) 3 bi-fundamentalfication model. An alternative "flipped" version of the quartification model is obtained by rearrangement of the particle assignments. The flipped model has two standard (bi-fundamentalfication) families and one flipped quartification family. In contrast to traditional product group unification models, flipped quartification stands out by featuring leptoquarks and thus allows for new mechanisms to explain the generation of neutrino masses and possible hints of lepton-flavor non-universality. [ABSTRACT FROM AUTHOR]

We investigate the recently reported tt¯ excess by the CMS Collaboration within the framework of conventional Two-Higgs-Doublet Models (2HDMs). Considering all four types (I, II, X, and Y), we perform a comprehensive parameter space scan using the best-fit values for a pseudoscalar boson A: MA=365 GeV, ΓA/MA=2%, and tan⁡β=1.28. Theoretical requirements and experimental constraints are systematically applied, including conditions from a bounded-below scalar potential, vacuum stability, unitarity, perturbativity, Flavor-Changing Neutral Currents (FCNCs), and direct searches at high-energy colliders. Our analysis shows that perturbativity imposes upper bounds of around 723 GeV on MH± and MH. FCNC constraints exclude all viable parameter space in Types II and Y, while a small region persists in Types I and X, but this region is ultimately ruled out by recent tt¯Z measurements by the ATLAS and CMS Collaborations at the LHC. We conclude that conventional 2HDMs alone cannot accommodate a pseudoscalar boson that explains the observed tt¯ excess within viable parameter space. However, incorporating toponium effects in the background fit could potentially alter this conclusion.

Rare meson decays are among the most sensitive probes of both heavy and light new physics. Among them, new physics searches using kaons benefit from their small total decay widths and the availability of very large datasets. On the other hand, useful complementary information is provided by hyperon decay measurements. We summarize the relevant phenomenological models and the status of the searches in a comprehensive list of kaon and hyperon decay channels. We identify new search strategies for under-explored signatures, and demonstrate that the improved sensitivities from current and next-generation experiments could lead to a qualitative leap in the exploration of light dark sectors.

Quark and lepton masses and mixings are considered in the framework of the microscopic model. The most general ansatz for the interactions among tetrons leads to a Hamiltonian HT$H_T$ involving Dzyaloshinskii‐Moriya (DM), Heisenberg and torsional isospin forces. Diagonalization of the Hamiltonian provides for 24 eigenvalues which are identified as the quark and lepton masses. While the masses of the third and second family arise from DM and Heisenberg type of isospin interactions, light family masses are related to torsional interactions among tetrons. Neutrino masses turn out to be special in that they are given in terms of tiny isospin non‐conserving DM, Heisenberg and torsional couplings. The approach not only leads to masses, but also allows to calculate the quark and lepton eigenstates, an issue, which is important for the determination of the CKM and PMNS mixing matrices. Compact expressions for the eigenfunctions of HT$H_T$ are given. The almost exact isospin conservation of the system dictates the form of the lepton states and makes them independent of all the couplings in HT$H_T$. As a consequence, a parameter‐free analytic expression for the PMNS matrix is derived which fits numerically all the measured matrix components. The formula includes a prediction of the leptonic Jarlskog invariant JPMNS=−0.0106$J_{PMNS}=-0.0106$. An outlook is given on the treatment of the CKM matrix. Quark and lepton masses and mixings are considered in the framework of the microscopic model. The most general ansatz for the interactions among tetrons leads to a Hamiltonian HT involving Dzyaloshinskii‐Moriya (DM), Heisenberg and torsional isospin forces. Diagonalization of the Hamiltonian provides for 24 eigenvalues which are identified as the quark and lepton masses. While the masses of the third and second family arise from DM and Heisenberg type of isospin interactions, light family masses are related to torsional interactions among tetrons. Neutrino masses turn out to be special in that they are given in terms of tiny isospin non‐conserving DM, Heisenberg and torsional couplings. The approach not only leads to masses, but also allows to calculate the quark and lepton eigenstates, an issue, which is important for the determination of the CKM and PMNS mixing matrices. Compact expressions for the eigenfunctions of HT are given. The almost exact isospin conservation of the system dictates the form of the lepton states and makes them independent of all the couplings in HT. As a consequence, a parameter‐free analytic expression for the PMNS matrix is derived which fits numerically all the measured matrix components. The formula includes a prediction of the leptonic Jarlskog invariant JPMNS = −0.0106. An outlook is given on the treatment of the CKM matrix. [ABSTRACT FROM AUTHOR]

Is there more to Dirac's gamma matrices than meets the eye? It turns out that gamma zero can be factorized into a product of three operators. This revelation facilitates the expansion of Dirac's space-time algebra to Clifford algebra Cl (0 , 6). The resultant rich geometric structure can be leveraged to establish a combined framework of the standard model and gravity, wherein a gravi-weak interaction between the vierbein field and the extended weak gauge field is allowed. Inspired by the composite Higgs model, we examine the vierbein field as an effective description of the fermion–antifermion condensation. The compositeness of space-time manifests itself at an energy scale which is different from the Planck scale. We propose that all the regular classical Lagrangian terms are of quantum condensation origin, thus possibly addressing the cosmological constant problem provided that we exercise extreme caution in the renormalization procedure that entails multiplications of divergent integrals. The Clifford algebra approach also permits a weaker form of charge conjugation without particle–antiparticle interchange, which leads to a Majorana-type mass that conserves lepton number. Additionally, in the context of spontaneous breaking of two global U (1) symmetries, we explore a three-Higgs-doublet model which could explain the fermion mass hierarchies. [ABSTRACT FROM AUTHOR]

The leading-order contribution of a new boson to the muonic fine-structure anomaly, which refers to a discrepancy between the predicted transition energies and spectroscopic measurements of μ−90Zr, μ−120Sn, and μ−208Pb, is investigated. We consider bosons of scalar, vector, pseudoscalar, and pseudovector type. Spin-dependent couplings sourced by pseudoscalars or pseudovectors are disfavoured as solutions to the anomaly due to the nuclei in question having vanishing angular momentum. Spin-independent interactions resulting from scalar or vector exchange are also disfavoured because no parameter space exists to simultaneously fit different atomic states of the same nucleus. Therefore, we conclude that a ‘Beyond-the-Standard-Model’ resolution of the muonic fine-structure anomaly is generally disfavoured, and the first-order solution by a single new boson is excluded.

We find that a big gap between indicators for the breaking strengths of the global chiral SU(2) and U(1) axial symmetries in the QCD of the standard model (SM) can be interpreted as a new fine-tuning problem. This may thus imply calling for a class beyond the SM, which turns out to favor having a new chiral symmetry, and the associated massless new quark is insensitive to the chiral SU(2) symmetry for the lightest up and down quarks so that the fine-tuning is relaxed. Our statistical estimate shows that QCD of the SM is by more than 300 standard deviations off the parameter space free from fine-tuning, and the significance will be greater as the lattice measurements on the QCD hadron observables become more accurate. We briefly address a dark QCD model with massless new quarks as one viable candidate. [ABSTRACT FROM AUTHOR]

A new paradigm for data-driven, model-agnostic new physics searches at colliders is emerging, and aims to leverage recent breakthroughs in anomaly detection and machine learning. In order to develop and benchmark new anomaly detection methods within this framework, it is essential to have standard datasets. To this end, we have created the LHC Olympics 2020, a community challenge accompanied by a set of simulated collider events. Participants in these Olympics have developed their methods using an R&D dataset and then tested them on black boxes: datasets with an unknown anomaly (or not). Methods made use of modern machine learning tools and were based on unsupervised learning (autoencoders, generative adversarial networks, normalizing flows), weakly supervised learning, and semi-supervised learning. This paper will review the LHC Olympics 2020 challenge, including an overview of the competition, a description of methods deployed in the competition, lessons learned from the experience, and implications for data analyses with future datasets as well as future colliders.

Abstract A search for pairs of dijet resonances with the same mass is conducted in final states with at least four jets. Results are presented separately for the case where the four jet production proceeds via an intermediate resonant state and for nonresonant production. The search uses a data sample corresponding to an integrated luminosity of 138 fb −1 collected by the CMS detector in proton-proton collisions at s $$ \sqrt{s} $$ = 13 TeV. Model-independent limits, at 95% confidence level, are reported on the production cross section of four-jet and dijet resonances. These first LHC limits on resonant pair production of dijet resonances via high mass intermediate states are applied to a signal model of diquarks that decay into pairs of vector-like quarks, excluding diquark masses below 7.6 TeV for a particular model scenario. There are two events in the tails of the distributions, each with a four-jet mass of 8 TeV and an average dijet mass of 2 TeV, resulting in local and global significances of 3.9 and 1.6 standard deviations, respectively, if interpreted as a signal. The nonresonant search excludes pair production of top squarks with masses between 0.50 TeV to 0.77 TeV, with the exception of a small interval between 0.52 and 0.58 TeV, for supersymmetric R-parity-violating decays to quark pairs, significantly extending previous limits. Here, the most significant excess above the predicted background occurs at an average dijet mass of 0.95 TeV, for which the local and global significances are 3.6 and 2.5 standard deviations, respectively.

[Display omitted] Inspired by the recent evidences of nano-Hertz stochastic gravitational waves observed by the pulsar timing array collaborations, we explore their implied supercooled electroweak phase transition in the singlet extension of the standard model. Our findings reveal that by adjusting the model parameter at per milli level, the corresponding percolation temperature can be continuously lowered to 1 GeV. With such a low percolation temperature, the singlet dark matter may freeze out before the electroweak phase transition, and, consequently, the entropy generated during the transition can significantly affect the dark matter relic density. It alleviates the tension between the requirement of a strong electroweak phase transition and the constraints imposed by dark matter direct detection, and can be tested in future experiments. [ABSTRACT FROM AUTHOR]

The recent high precision measurement of W boson mass by CDF-II collaboration points to the contribution(s) of new physics beyond the Standard Model (SM). One of the minimalistic ways to account for the anomalous W boson mass is by introducing a hyperchargeless real SU (2) L triplet scalar whose vacuum expectation value (VEV) explicitly contributes to the W boson mass at the tree level while the Z boson mass remains the same. Such a triplet can be naturally embedded in a singlet-triplet scotogenic model for one-loop neutrino mass generated by dark sector particles running in the loop. We discuss the detailed phenomenology of the model, obtaining the parameter space consistent with the CDF-II W boson mass measurements. The dark matter as well as the constraints comings from S , T , U parameters are also analyzed. [ABSTRACT FROM AUTHOR]

We show that the dynamics of the scalar Higgs field in the Abelian Higgs–Kibble model supplemented with a dimension-6 derivative operator can be constrained at the quantum level by a certain stability equation. It holds in the Landau gauge and is derived within the recently proposed extended field formalism, where the physical scalar is described by a gauge-invariant field variable. Physical implications of the stability equation are discussed. [ABSTRACT FROM AUTHOR]

Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton-proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments-as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER-to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity 'dark showers', highlighting opportunities for expanding the LHC reach for these signals.

Six-dimensional spinors with Spin(3,3) symmetry are utilized to efficiently encode three generations of matter. E8(−24) is shown to contain physically relevant subgroups with representations for GUT groups, spacetime symmetries, three generations of the standard model fermions, and Higgs bosons. Pati–Salam, SU(5), and Spin(10) grand unified theories are found when a single generation is isolated. For spacetime symmetries, Spin(4,2) may be used for conformal symmetry, AdS5→dS4, or simply broken to Spin(3,1) of a Minkowski space. Another class of representations finds Spin(2,2) and can give AdS3 with various GUTs. An action for three generations of fermions in the Majorana–Weyl spinor 128 of Spin(4,12) is found with Spin(3) flavor symmetry inside E8(−24). The 128 of Spin(12,4) can be regarded as the tangent space to a particular pseudo-Riemannian form of the octo-octonionic Rosenfeld projective plane E8(−24)/Spin(12,4)=(OsxO)P2.

Since its start, the Large Hadron Collider (LHC) has helped advance both theory and experiment on the production and properties of the heaviest fundamental particle, the top quark. This review focuses on a selected set of measurements and associated searches for new physics, which have opened the door for unprecedented precision in this area of high-energy physics. Fundamental parameters of the theory such as mt, αS, Vtb, and yt are measured from top quark events with relative uncertainties that are smaller than 0.5%, 1.8%, 2%, and 10%, respectively, and that are expected to improve with more data, better experimental methods, and more accurate theory predictions. Several results, even if statistically limited, already significantly constrain the phase space of new physics: measurements of associated production with bosons, processes with four top quarks, and searches for rare decays, among others. It is expected that until the completion of the LHC program, top quark physics will keep providing unique insights regarding the consistency of the Standard Model and the energy scale of new physics. [ABSTRACT FROM AUTHOR]

In this article, I review scenarios of physics beyond the Standard Model in which the top quark plays a special role. Models that aim at the stabilization of the weak scale are presented together with the specific phenomenology of partner states that are characteristic of this type of model. Further, I present models of flavor in which the top quark is singled out as a special flavor in the Standard Model. The flavor and collider phenomenology of these models is broadly presented. Finally, I discuss the possibility that dark matter interacts preferably with the top quark flavor and give an overview of the dark matter phenomenology of these scenarios, as well as collider and flavor signals. [ABSTRACT FROM AUTHOR]

Laboratory search of exotic interactions is crucial for exploring physics beyond the standard model. We report new experimental constraints on two exotic spin-dependent interactions at the micrometer scale based on ensembles of nitrogen-vacancy (NV) centers in diamond. A thin layer of NV electronic spin ensembles is synthesized as the solid-state spin quantum sensor, and a lead sphere is taken as the interacting nucleon source. Our result establishes new bounds for two types of exotic spin interactions at the micrometer scale. For an exotic parity-odd spin- and velocity-dependent interaction, improved bounds are set within the force range from 5 to 500 μm. The upper limit of the corresponding coupling constant |$g_A^eg_V^N$| at 330 μm is more than 1000-fold more stringent than the previous constraint. For the P, T -violating scalar-pseudoscalar nucleon-electron interaction, improved constraints are established within the force range from 6 to 45 μm. The limit of the corresponding coupling constant |$g_S^Ng_P^e$| is improved by more than one order of magnitude at 30 μm. This work demonstrates that a solid-state NV ensemble can be a powerful platform for probing exotic spin-dependent interactions. [ABSTRACT FROM AUTHOR]

The two discrete generators of the full Lorentz group O (1 , 3) in 4 D spacetime are typically chosen to be parity inversion symmetry P and time reversal symmetry T, which are responsible for the four topologically separate components of O (1 , 3) . Under general considerations of quantum field theory (QFT) with internal degrees of freedom, mirror symmetry is a natural extension of P, while C P symmetry resembles T in spacetime. In particular, mirror symmetry is critical as it doubles the full Dirac fermion representation in QFT and essentially introduces a new sector of mirror particles. Its close connection to T-duality and Calabi–Yau mirror symmetry in string theory is clarified. Extension beyond the Standard Model can then be constructed using both left- and right-handed heterotic strings guided by mirror symmetry. Many important implications such as supersymmetry, chiral anomalies, topological transitions, Higgs, neutrinos, and dark energy are discussed. [ABSTRACT FROM AUTHOR]

A search for pairs of dijet resonances with the same mass is conducted in final states with at least four jets. Results are presented separately for the case where the four jet production proceeds via an intermediate resonant state and for nonresonant production. The search uses a data sample corresponding to an integrated luminosity of 138 fb−1 collected by the CMS detector in proton-proton collisions at s = 13 TeV. Model-independent limits, at 95% confidence level, are reported on the production cross section of four-jet and dijet resonances. These first LHC limits on resonant pair production of dijet resonances via high mass intermediate states are applied to a signal model of diquarks that decay into pairs of vector-like quarks, excluding diquark masses below 7.6 TeV for a particular model scenario. There are two events in the tails of the distributions, each with a four-jet mass of 8 TeV and an average dijet mass of 2 TeV, resulting in local and global significances of 3.9 and 1.6 standard deviations, respectively, if interpreted as a signal. The nonresonant search excludes pair production of top squarks with masses between 0.50 TeV to 0.77 TeV, with the exception of a small interval between 0.52 and 0.58 TeV, for supersymmetric R-parity-violating decays to quark pairs, significantly extending previous limits. Here, the most significant excess above the predicted background occurs at an average dijet mass of 0.95 TeV, for which the local and global significances are 3.6 and 2.5 standard deviations, respectively. [ABSTRACT FROM AUTHOR]

The LHC and direct detection experiments have had the most interesting possible outcome: the observation of a Higgs boson in isolation. This has left a void in theoretical particle physics, making the traditional questions on the origin of the weak scale and on the nature of dark matter deeper and more confusing than ever. The field has responded by producing a number of ideas that trace the answer to these questions to the early history of the Universe. At the same time, a number of new probes of the evolution of the Universe are planned or are already recording data. This calls for a meeting place where particle physicists, astrophysicists and cosmologists can join forces to refine theoretical ideas, find new experimental targets and benefit from the expertise needed to answer the most pressing questions in fundamental physics. This workshop offered the particle physics community access to a wealth of present and future cosmological data. It also gave, to the astrophysics and cosmology communities, an overview of the latest ideas that connect their disciplines to the fundamental laws of particle interactions. [ABSTRACT FROM AUTHOR]

This paper reviews the puzzles in modern neutron lifetime measurements and related unitarity issues in the CKM matrix. It is not a comprehensive and unbiased compilation of all historic data and studies, but rather a focus on compelling evidence leading to new physics. In particular, the largely overlooked nuances of different techniques applied in material and magnetic trap experiments are clarified. Further detailed analysis shows that the "beam" approach of neutron lifetime measurements is likely to give the "true" β -decay lifetime, while discrepancies in "bottle" measurements indicate new physics at play. The most feasible solution to these puzzles is a newly proposed ordinary-mirror neutron ( n − n ′ ) oscillation model under the framework of mirror matter theory. This phenomenological model is reviewed and introduced, and its explanations of the neutron lifetime anomaly and possible non-unitarity of the CKM matrix are presented. Most importantly, various new experimental proposals, especially lifetime measurements with small/narrow magnetic traps or under super-strong magnetic fields, are discussed in order to test the surprisingly large anomalous signals that are uniquely predicted by this new n − n ′ oscillation model. [ABSTRACT FROM AUTHOR]

In a long series of works, it has been demonstrated that the spin-charge-family theory, assuming a simple starting action in even dimensional spaces with d ≥ (13 + 1) , with massless fermions interacting with gravity only, offers the explanation for all assumed properties of the second quantized fermion and boson fields in the standard model, as well as offering predictions and explanations for several of the observed phenomena. The description of the internal spaces of the fermion and boson fields by the Clifford odd and even objects, respectively, justifies the choice of the simple starting action of the spin-charge-family theory. The main topic of the present article is the analysis of the properties of the internal spaces of the fermion and boson fields in odd dimensional spaces, d = (2 n + 1) , which can again be described by the Clifford odd and even objects, respectively. It turns out that the properties of fermion and boson fields differ essentially from their properties in even dimensional spaces, resembling the ghosts needed when looking for final solutions with Feynman diagrams. [ABSTRACT FROM AUTHOR]

High-energy colliders provide direct access to the energy frontier, allowing to search for new physics at scales as high as the machine’s center-of-mass energy, perform precision measurements of the Standard Model (SM) parameters, including those related to the flavor sector, and determine the Higgs boson properties and their connection to electroweak symmetry breaking. Each proposed future collider option has its own specific science goals and capabilities, depending on the designed running energy (energies) amongst other parameters. In this paper, an overview of the discovery potential of future circular and linear colliders is presented. Results from searches for beyond the Standard Model (BSM) phenomena at proton–proton, proton–electron, electron–positron, and muon–antimuon colliders are summarized.

This article is an addendum to Ref. [1]. We discuss the correlation of K0→π0νν¯ with the K+→π+νν¯ and B→hsνν¯ modes in the model for NP contributions discussed in Ref. [1].Report Number: BARI-TH/22-737

Axion–Like–Particles are among the most economical and well motivated extensions of the Standard Model. In this work ALP production from hadronic and leptonic meson decays are studied. The hadronization part of these decay amplitudes have been obtained using Brodsky–Lepage method or LQCD, at needs. In particular, the general expressions for ALP emission in mesonic s– and t–channel tree–level processes are thoroughly discussed, for pseudoscalar and vector mesons. Accordingly, the calculation of the decay amplitudes for MI→MFa$M_I\rightarrow M_F \,a$ and M→ℓνa$M\rightarrow \ell \nu a$ are presented. Finally, bounds on the (low–energy effective Lagrangian) ALP–fermion couplings are derived, from present and future flavor experiments. Axion–Like–Particles are among the most economical and well motivated extensions of the Standard Model. In this work ALP production from hadronic and leptonic meson decays are studied. The hadronization part of these decay amplitudes have been obtained using Brodsky–Lepage method or LQCD, at needs. In particular, the general expressions for ALP emission in mesonic s– and t–channel tree–level processes are thoroughly discussed, for pseudoscalar and vector mesons. Accordingly, the calculation of the decay amplitudes for MI→MFa$M_I\rightarrow M_F \,a$ and M→ℓνa$M\rightarrow \ell \nu a$ are presented. Finally, bounds on the (low–energy effective Lagrangian) ALP–fermion couplings are derived from present and future flavor experiments. [ABSTRACT FROM AUTHOR]

Six-dimensional spinors with S p i n (3 , 3) symmetry are utilized to efficiently encode three generations of matter. E 8 (− 24) is shown to contain physically relevant subgroups with representations for GUT groups, spacetime symmetries, three generations of the standard model fermions, and Higgs bosons. Pati–Salam, S U (5) , and S p i n (10) grand unified theories are found when a single generation is isolated. For spacetime symmetries, S p i n (4 , 2) may be used for conformal symmetry, A d S 5 → d S 4 , or simply broken to S p i n (3 , 1) of a Minkowski space. Another class of representations finds S p i n (2 , 2) and can give A d S 3 with various GUTs. An action for three generations of fermions in the Majorana–Weyl spinor 128 of S p i n (4 , 12) is found with S p i n (3) flavor symmetry inside E 8 (− 24) . The 128 of S p i n (12 , 4) can be regarded as the tangent space to a particular pseudo-Riemannian form of the octo-octonionic Rosenfeld projective plane E 8 (− 24) / S p i n (12 , 4) = (O s x O) P 2 . [ABSTRACT FROM AUTHOR]

In the extended scalar sector of the SMASH (Standard Model - Axion-Seesaw-Higgs portal inflation) framework, we conduct a phenomenological investigation of the observable effects. In a suitable region of the SMASH scalar parameter spaces, we solve the vacuum metastability problem and discuss the one-loop correction to the triple Higgs coupling, λ H H H . The λ H H H and SM Higgs quartic coupling λ H corrections are found to be proportional to the threshold correction. A large λ H H H correction (≳5%) implies vacuum instability in the model and thus limits the general class of theories that use threshold correction. We performed a full two-loop renormalization group analysis of the SMASH model. The SMASH framework has also been used to estimate the evolution of lepton asymmetry in the universe. [ABSTRACT FROM AUTHOR]

Many beyond the Standard Model signatures predict new physics phenomena that lead to final states containing both leptons and jets. The latest search results for massive particles or lepton flavor violation using the full Run 2 dataset recorded by the ATLAS experiment are presented. A particular focus is given to searches for leptoquarks, that offer an attractive potential explanation for the lepton flavor anomalies observed at B -physics factories; searches for heavy leptons, such as the ones appearing in Type-III seesaw model that can explain the smallness of neutrino masses; and lepton flavor violating Z decays, which is an excellent probe for new physics that predict direct lepton flavor violating processes. [ABSTRACT FROM AUTHOR]

In this special edition, we overview the progress and present status of the Glashow-Weinberg-Salam (GWS) theory, widely recognized as the Standard Model (SM) of particle physics, followed by critical reviews of several scenarios that go beyond the SM. [ABSTRACT FROM AUTHOR]