Universal Couplings Research Articles

Model-independent analysis of new physics effects in B→K2∗(1430)μ+μ-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B\\rightarrow K^*_2(1430)\\mu ^+ \\mu ^-$$\\end{document} decay

Recently, the LHCb Collaboration provided updated measurements for the lepton flavour ratios RK\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R_K$$\\end{document} and RK∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R_{K^*}$$\\end{document}. The currently observed values align with the predictions of the standard model. In light of these recent updates, our investigation delves into the repercussions of new physics characterized by universal couplings to electrons and muons. We specifically focus on their impact on various observables within the B→K2∗(1430)(→Kπ)μ+μ-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B\\rightarrow K_2^*(1430)(\\rightarrow K\\pi )\\mu ^+ \\mu ^-$$\\end{document} decay. These observables include the differential branching ratio, forward-backward asymmetry (AFB\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$A_{FB}$$\\end{document}), longitudinal polarization asymmetry (FL\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$F_L$$\\end{document}), and a set of optimized observables (Pi\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$P_i$$\\end{document}). Our findings indicate that the branching ratio of B→K2∗(→Kπ)μ+μ-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B\\rightarrow K_2^*(\\rightarrow K\\pi )\\mu ^+ \\mu ^-$$\\end{document} decay can be suppressed up to 25%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$25\\%$$\\end{document} for various new physics solutions. Furthermore, all permissible new physics scenarios demonstrate finite enhancement in the muon forward-backward asymmetry (AFB)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(A_{FB})$$\\end{document} as well as an increase in the value of the optimized angular observable P2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$P_2$$\\end{document}. Moreover, in the presence of new physics zero crossing points for AFB\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$A_{FB}$$\\end{document} and P2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$P_2$$\\end{document} shift towards higher q2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$q^2$$\\end{document}. The current data have a mild deviation from SM predictions in P5′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$P_5'$$\\end{document} observable in the low-q2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$q^2$$\\end{document} bin. We also explored massive Z′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z'$$\\end{document} models, which can generate universal 1D new physics scenarios, characterized by C9NP<0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$C_9^{NP}<0$$\\end{document}, C9NP=-C10NP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$C_9^{NP}=-C_{10}^{NP}$$\\end{document}, and C9NP=-C9′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$C_9^{NP}=-C_9'$$\\end{document}. Using additional constraints coming from Bs-Bs¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B_s-\\overline{B_s}$$\\end{document} mixing and neutrino trident process, we find that the conclusions of the model-independent analysis remain valid.

Genuine lepton-flavor-universality-violating observables in the τ−μ sector of B→(K,K*)ℓℓ decays

It was previously shown that unlike the ratios RKμe≡RK≡Γ(B→Kμ+μ−)/Γ(B→Ke+e−) and RK*μe≡RK*≡Γ(B→K*μ+μ−)/Γ(B→K*e+e−), the ratios RKτμ and RK*τμ can deviate from their Standard Model (SM) predictions even with universal new physics couplings. This observation highlights the critical need to identify and establish genuine lepton flavor universality violating (LFUV) observables in the τ−μ sector. This work embarks on establishing genuine LFUV ratio observables in B→Kℓℓ and B→K*ℓℓ decays through comprehensive analysis of their angular distributions. We find that like RK*τμ, the ratios RAFBτμ and RfLτμ do not qualify as genuine LFUV observables, whereas the ratios of all optimized observables in B→K*ℓℓ decays within the τ−μ sector definitively do. In the case of B→Kℓℓ decays, similar to RKτμ, the ratio RFH is influenced by mass effects and therefore cannot be considered a genuine LFUV observable in the τ−μ sector. However, the ratio Γτ(1−FHτ)/Γμ(1−FHμ) stands as the sole genuine LFUV observable in B→Kℓℓ decays. Furthermore, by making use of new physics Lorentz structures which provide a better fit to the current b→sℓℓ data as compared to the SM, we demonstrate how the nongenuine LFUV ratios RAFBτμ and RfLτμ can be employed to distinguish between framework with solely universal lepton couplings and those with both universal and nonuniversal couplings. Published by the American Physical Society 2024

Axion-like particles in radiative quarkonia decays

Radiative quarkonia decays offer an ideal setting for probing Axion-Like Particle (ALP) interactions. This paper provides a comprehensive review of ALP production mechanisms through the e+e− → γa process at B- and Charm-factories, alongside an analysis of potential ALP decay channels. We derive constraints on ALP couplings to Standard Model (SM) fields, based on recent experimental results on quarkonia decays by the Belle II and BESIII collaborations. The analysis distinguishes between “invisible” and “visible” ALP decay scenarios. The “invisible” scenario, characterised by a mono-γ plus missing-energy signature, enables stringent limits on ALP-photon and ALP-quark (b or c) couplings. Moreover, extensive research at flavour factories has explored various “visible” ALP decays into SM final states, which depend on a larger set of ALP-SM couplings. To streamline the “visible” ALP scenario, we introduce additional theoretical assumptions, such as universal ALP-fermion couplings, or we adopt specific benchmark ALP models, aiming to minimise the number of independent variables in our analysis.

Phenomenology of axionlike particles with universal fermion couplings revisited

Axionlike particles (ALPs) emerge in many extensions of the Standard Model as pseudo-Goldstone bosons of a spontaneously broken global symmetry. Understanding their phenomenology in high-energy collisions is crucial for optimizing experimental searches and understanding the exploration potential of future experiments. In this paper, we revise the phenomenology of ALPs with universal couplings to fermions. In particular, we analyze the hierarchy and uncertainty of the various ALP production channels depending on the proton collision energy and the placement of the experiment, and provide improved calculations of the hadronic decay modes. Published by the American Physical Society 2024

Investigating the potential of [formula omitted] to probe lepton flavor universality violation

In this work we study the potential of the lepton flavor ratios RKτμ≡Γ(B→Kτ+τ−)/Γ(B→Kμ+μ−) and RK⁎τμ≡Γ(B→K⁎τ+τ−)/Γ(B→K⁎μ+μ−) to probe lepton flavor universality (LFU) violation in τ−μ sector. We show that these ratios can deviate from their SM values even if the new physics couplings are universal in nature, i.e., having equal couplings to e, μ and τ leptons. Therefore in order to utilize these observables to probe LFU violation, we need to compare the allowed range of RK(⁎)τμ for class of solutions with only universal couplings to leptons and solutions having both universal and non-universal components. For the current b→sℓℓ (ℓ=e,μ) data, we find that these two class of solutions can be discriminated provided the measured value of RK⁎τμ is greater than the SM prediction.

Collider constraints on massive gravitons coupling to photons

We study the discovery potential of massive graviton-like spin-2 particles coupled to standard model fields, produced in photon-photon collisions at the Large Hadron Collider (LHC) as well as in electron-positron (e+e−) collisions, within an effective theory with and without universal couplings. Our focus is on a massive graviton G coupled to the electromagnetic field, which decays via G→γγ and leads to a resonant excess of diphotons over the light-by-light scattering continuum at the LHC, and of triphoton final states at e+e− colliders. Based on similar searches performed for pseudoscalar axion-like particles (ALPs), and taking into account the different cross sections, γγ partial widths, and decay kinematics of the pseudoscalar and tensor particles, we reinterpret existing experimental bounds on the ALP-γ coupling into G-γ ones. Using the available data, exclusion limits on the graviton-photon coupling are set down to gGγ≈1–0.05 TeV−1 for masses mG≈100 MeV–2 TeV. Such bounds can be improved by factors of 100 at Belle II in the low-mass region, and of 4 at the HL-LHC at high masses, with their expected full integrated luminosities.

Light new physics and neutrino electromagnetic interactions in XENONnT

We derive new limits on the neutrino electromagnetic interactions and weakly coupled light vector and scalar mediators using the recent XENONnT data of the solar neutrino-electron elastic scattering. XENONnT has already reported the world's best constraint on the flavor-independent effective neutrino magnetic moment with almost twice the exposure and improved systematics. We extend this analysis and derive constraints on all the possible electromagnetic interactions and flavor universal light gauge boson couplings and masses, which could contribute to the neutrino-electron elastic scattering process. We consider both flavor-independent and flavor-dependent interactions of the neutrino magnetic moments, millicharges, charge radii, and anapole moments for the electromagnetic interactions. The new limits on the magnetic moment, millicharge, vector, and scalar interactions are improved by about one order of magnitude. At the same time, there is relatively weaker improvement in the case of neutrino charge radii and anapole moments.

Disentangling lepton flavor universal and lepton flavor universality violating effects in b→sℓ+ℓ− transitions

In this letter we propose a strategy for discerning if new physics in the Wilson coefficient ${\cal C}_{9\mu}$ is dominantly lepton flavour universality violating or if it contains a sizable lepton flavour universal component (${\cal C}_9^{\rm U}$). Distinguishing among these two cases, for which the model independent fit of the related scenarios exhibits similar pulls w.r.t. the Standard Model, is crucial to advance our understanding of the $B$ anomalies. We first identify the origin of the degeneracy of these two cases and point out the key observables that can break it. In particular, while the observables measured so far that test lepton flavour universality exhibit similar dependencies to all the relevant Wilson coefficients, the forthcoming measurement of $Q_5=P_{5}^{\prime\mu}-P_{5}^{\prime e}$ is particularly sensitive to ${\cal C}_{9\mu}-{\cal C}_{9e}$. In fact, if $Q_5$ were found to be small (i.e. close to its Standard Model value), this would imply a small ${\cal C}_{9\mu}-{\cal C}_{9e}$ but a sizable ${\cal C}_{9}^{\rm U}$, given the preference of global fits for a large negative new physics contribution in ${\cal C}_{9\mu}$. We discuss the possible origins of ${\cal C}_9^{\rm U}$, in particular how it could originate from new physics. Here, a promising scenario, that could even link $b\to s \ell^+\ell^-$ to $R_{D^{(*)}}$, is the one in which ${\cal C}_9^{\rm U}$ is generated from a tau loop via an off-shell photon penguin diagram. This setup predicts the branching ratios of $B_s\to\tau^+\tau^-$ and $B\to K^{(*)}\tau^+\tau^-$ to lie within the reach of LHCb, CMS and Belle II. Alternatively, in case of a non-observation of these tauonic processes, we show that the most natural possibility to generate ${\cal C}_9^{\rm U}$ is a $Z^\prime$ with partially lepton flavour universal couplings.

Mechanical properties of nucleic acids and the non-local twistable wormlike chain model.

Mechanical properties of nucleic acids play an important role in many biological processes that often involve physical deformations of these molecules. At sufficiently long length scales (say, above ∼20-30 base pairs), the mechanics of DNA and RNA double helices is described by a homogeneous Twistable Wormlike Chain (TWLC), a semiflexible polymer model characterized by twist and bending stiffnesses. At shorter scales, this model breaks down for two reasons: the elastic properties become sequence-dependent and the mechanical deformations at distal sites get coupled. We discuss in this paper the origin of the latter effect using the framework of a non-local Twistable Wormlike Chain (nlTWLC). We show, by comparing all-atom simulations data for DNA and RNA double helices, that the non-local couplings are of very similar nature in these two molecules: couplings between distal sites are strong for tilt and twist degrees of freedom and weak for roll. We introduce and analyze a simple double-stranded polymer model that clarifies the origin of this universal distal couplings behavior. In this model, referred to as the ladder model, a nlTWLC description emerges from the coarsening of local (atomic) degrees of freedom into angular variables that describe the twist and bending of the molecule. Different from its local counterpart, the nlTWLC is characterized by a length-scale-dependent elasticity. Our analysis predicts that nucleic acids are mechanically softer at the scale of a few base pairs and are asymptotically stiffer at longer length scales, a behavior that matches experimental data.

Test of the universality of \u03c4 and \u03bc lepton couplings in W-boson decays with the ATLAS detector

The standard model of particle physics encapsulates our best current understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the electroweak gauge bosons. The measurement of the ratio of the decay rate of W bosons to τ leptons and muons, R(τ/μ), constitutes an important test of this axiom. Using 139 fb−1 of proton–proton collisions recorded with the ATLAS detector at a centre-of-mass energy of 13 TeV, we report a measurement of this quantity from di-leptonic toverline{t} events where the top quarks decay into a W boson and a bottom quark. We can distinguish muons originating from W bosons and those originating from an intermediate τ lepton through the muon transverse impact parameter and differences in the muon transverse momentum spectra. The measured value of R(τ/μ) is 0.992 ± 0.013 [± 0.007(stat) ± 0.011(syst)] and is in agreement with the hypothesis of universal lepton couplings as postulated in the standard model. This is the only such measurement from the Large Hadron Collider, so far, and obtains twice the precision of previous measurements.

Oscillations and stability in the coupled mechanical system

Conservative mechanical systems are considered. Each system is supposed to admit a family of non-degenerate symmetric periodic motions. For the entire set of systems, they form a family of conditionally periodic oscillations, which is assumed to contain a symmetrical periodic motion. Universal couplings for mechanical systems are proposed such that they play the role of controls that ensure the existence, stability, and stabilization of oscillations at the same time for the whole system. Those couplings provide the natural, i.e. without involving any additional controls, stabilization of the oscillation. In addition, mechanical systems perform the synchronization in frequency and phase.

Beyond self-acceleration: Force- and fluid-acceleration

The notion of self acceleration has been introduced as a convenient way to theoretically distinguish cosmological models in which acceleration is due to modified gravity from those in which it is due to the properties of matter or fields. In this paper we review the concept of self acceleration as given, for example, by [1], and highlight two problems. First, that it applies only to universal couplings, and second, that it is too narrow, i.e. it excludes models in which the acceleration can be shown to be induced by a genuine modification of gravity, for instance coupled dark energy with a universal coupling, the Hu-Sawicki f(R) model or, in the context of inflation, the Starobinski model. We then propose two new, more general, concepts in its place: force-acceleration and field-acceleration, which are also applicable in presence of non universal cosmologies. We illustrate their concrete application with two examples, among the modified gravity classes which are still in agreement with current data, i.e. f(R) models and coupled dark energy.

A nonunitary interpretation for a single vector leptoquark combined explanation to the B-decay anomalies

In order to simultaneously account for both RD(∗) and RK (∗) anomalies in B-decays, we consider an extension of the Standard Model by a single vector leptoquark field, and study how one can achieve the required lepton flavour non-universality, starting from a priori universal gauge couplings. While the unitary quark-lepton mixing induced by SU(2)L breaking is insufficient, we find that effectively nonunitary mixings hold the key to simultaneously address the RK (∗) and RD(∗) anomalies. As an intermediate step towards various UV-complete models, we show that the mixings of charged leptons with additional vector-like heavy leptons successfully provide a nonunitary framework to explain RK (∗) and RD(∗) . These realisations have a strong impact for electroweak precision observables and for flavour violating ones: isosinglet heavy lepton realisations are already excluded due to excessive contributions to lepton flavour violating Z -decays. Furthermore, in the near future, the expected progress in the sensitivity of charged lepton flavour violation experiments should allow to fully probe this class of vector leptoquark models.

The structure, geometry, and kinematics of a universal joint

The paper briefly presents the geometry, structure, and kinematics of a universal joint, very commonly used in machine building, especially today for heavy and engine-driven vehicles and transmissions located in different areas as well as for all-wheel-drive vehicles. The universal joint, or the cardan cross, conveys the rotation movement from one bridge to the other (when the rotary shaft suffers both movements, upward and downward). The kinematic scheme of a cardan transmission is composed of two cardan shafts (one input and one output), both of which are equipped with a cardan cross (universal joint or universal joint). Between the two universal couplings, a further (additional) cardan shaft (axle) is mounted. This mechanism is designed to transmit the mechanical movement (within a vehicle) from one bridge to the other. If the vehicle's motor is on the front and with on the rear axle transmission, or vice versa when the vehicle's engine is on the rear and the transmission is on the front axle, or when we have multiple (multi-axle) transmission on heavy vehicles or 4x4 cars.

Fermion mass hierarchy and phenomenology in the 5D Domain Wall Standard Model

We have recently proposed a setup of the “Domain-Wall Standard Model” in 5D spacetime, where all the Standard Model (SM) fields are localized in certain domains of the extra 5th dimension. Utilizing this setup, we attempt to solve the fermion mass hierarchy problem of the SM. The mass hierarchy can be naturally explained by suitably distributing the fermions in different positions along the extra dimension. Due to these different localization points, the effective 4D gauge couplings of Kaluza-Klein (KK) mode gauge bosons to the SM fermions become non-universal. As a result, our model is severely constrained by the Flavor Changing Neutral Current (FCNC) measurements. We find two interesting cases in which our model is phenomenologically viable: (1) the KK-mode of the SM gauge bosons are extremely heavy and unlikely to be produced at the Large Hadron Collider (LHC), while future FCNC measurements can reveal the existence of these heavy modes. (2) the width of the localized SM fermions is very narrow, leading to almost universal 4D KK-mode gauge couplings. In this case, the FCNC constraints can be easily avoided even if a KK gauge boson mass lies at the TeV scale. Such a light KK gauge boson can be searched at the LHC in the near future.

Dark matter in the Randall-Sundrum model with non-universal coupling

We consider simplified dark matter models (DM) interacting gravitationally with the standard model (SM) particles in a Randall-Sundrum (RS) framework. In this framework, the DM particles interact through the exchange of spin-2 Kaluza-Klein (KK) gravitons in the s-channel with the SM particles. The parameter space of the RS model with universal couplings to SM particles is known to be strongly constrained from the LHC data. We are thus led to consider models with non-universal couplings. The first model we consider in this study is a top-philic graviton model in which only the right-handed top quarks are taken to interact strongly with the gravitons. In the second, the lepto-philic model, we assume that only the right-handed charged leptons interact strongly with the gravitons. We extend the study to include not only the scalar, vector and spin-1/2 fermions but also spin-3/2 fermionic dark matter. We find that there is a large parameter space in these benchmark models where it is possible to achieve the observed relic density consistent with the direct and indirect searches and yet not to be constrained from the LHC data.

Scalar democracy

We conjecture that there exists a scalar bound state for every pair of fundamental fermions at a UV (`composite') scale, $\Lambda\gg v_{\text{weak}}$. This implies a large number of universally coupled, sub-critical Higgs doublets. All but the Standard Model Higgs are `dormant,' with large positive squared masses and each receives a small vacuum expectation values via mixing with the Standard Model Higgs. Universal couplings, modulo renormalization group running effects, flips the flavor problem into the masses and mixings of the Higgs system. Doublets associated with heavy fermion masses, $b,c, \tau$ likely lie in the multi-TeV range, but may be observable at the current LHC, or a high-luminosity and/or an energy-upgraded LHC. In the lepton sector we are lead to a Higgs seesaw for neutrino masses, and corollary processes of observable flavor violation. The observation of the first sequential doublet coupled to $\bar{b}b$ with masses $\lesssim 3.5$ TeV would lend credence to the hypothesis.

Full distribution of clusters with universal couplings and in-medium effects

Light and heavy clusters are calculated for asymmetric warm nuclear matter in a relativistic mean-field approach. In-medium effects, introduced via a universal cluster-meson coupling, and a binding energy shift contribution, calculated in a Thomas-Fermi approximation, were taken into account. This work considers, besides the standard lightest bound clusters $^4$He, $^3$He, $^3$H, and $^2$H, also stable and unstable clusters with higher number of nucleons, in the range $5\leq A \leq 12$, as it is natural that heavier clusters also form in core-collapse supernova matter, before the pasta phases set in. We show that these extra degrees of freedom contribute with non-negligible mass fractions to the composition of nuclear matter, and may prevail over deuterons and $\alpha$ particles at high density in strongly asymmetric matter, and not too high temperatures. The presence of the light clusters reduces the contribution of heavy clusters to a much smaller density range, and to a smaller mass fraction.

Thick shell regime in the chameleon two-body problem

In a previous paper [Phys. Rev. D 97, 104044 (2018)] we pointed out some shortcomings of the standard approach to chameleon theories consisting in treating the small bodies used to test the weak equivalence principle (WEP) as test particles, whose presence do not modify the chameleon field configuration. In that paper we developed an alternative method to determine the relevant field configuration which takes into account the influence of both test and source bodies, and computed the chamaleon mediated force. Relying on that analysis we showed that the effective acceleration of test bodies is composition dependent even when the model is based on universal couplings. In this paper, we improve our method by using a more suitable approximation for the effective chameleon potential in situations where the bodies are in the so-called "thick shell regime". We then find new and more restrictive bounds on the model' s parametres by confronting the new theoretical predictions with the empirical bounds on E\"otv\"os parameter comming from the lunar laser ranging experiments.

Hunting all the hidden photons

We explore constraints on gauge bosons of a weakly coupled U(1)B − L, mathrm{U}{(1)}_{L_{mu }-{L}_e},kern0.5em mathrm{U}{(1)}_{L_e-{L}_{tau }}kern0.5em mathrm{and}kern0.5em mathrm{U}{(1)}_{L_{mu }-{L}_{tau }} . To do so we apply the full constraining power of experimental bounds derived for a hidden photon of a secluded U(1)X and translate them to the considered gauge groups. In contrast to the secluded hidden photon that acquires universal couplings to charged Standard Model particles through kinetic mixing with the photon, for these gauge groups the couplings to the different Standard Model particles can vary widely. We take finite, computable loop-induced kinetic mixing effects into account, which provide additional sensitivity in a range of experiments. In addition, we collect and extend limits from neutrino experiments as well as astrophysical and cosmological observations and include new constraints from white dwarf cooling. We discuss the reach of future experiments in searching for these gauge bosons.