We discuss new bounds on vectors coupled to currents whose nonconservation is due to mass terms, such as $U(1{)}_{L_{\mu }-L_{\tau }}$. Due to the emission of many final state longitudinally polarized gauge bosons, inclusive rates grow exponentially fast in energy, leading to constraints that are only logarithmically dependent on the symmetry breaking mass term. This exponential growth is unique to Stueckelberg theories and reverts back to polynomial growth at energies above the mass of the radial mode. We present bounds coming from the high transverse mass tail of $\mathrm{monolepton}+\mathrm{MET}$ events at the LHC, which beat out cosmological bounds to place the strongest limit on Stueckelberg $U(1{)}_{L_{\mu }-L_{\tau }}$ models for most masses below a keV. We also discuss a stronger, but much more uncertain, bound coming from the validity of perturbation theory at the LHC.

We consider three-particle systems consisting of two identical particles and a third that is different, with all being spinless. Examples include ${\pi }^{+}{\pi }^{+}{K}^{+}$ and $K^{+}{K}^{+}{\pi }^{+}$. We derive the formalism necessary to extract two- and three-particle infinite-volume scattering amplitudes from the spectrum of such systems in finite volume. We use a relativistic formalism based on an all-orders diagrammatic analysis in generic effective field theory, adopting the methodology used recently to study the case of three nondegenerate particles. We present both a direct derivation, and also a cross-check based on an appropriate limit and projection of the fully nondegenerate formalism. We also work out the threshold expansions for the three-particle K matrix that will be needed in practical applications, both for systems with two identical particles plus a third, and also for the fully nondegenerate theory.

It is shown numerically, in a chiral U(1) gauge Higgs theory in which the left and right-handed fermion components have opposite U(1) charges, that the spectrum of gauge and Higgs fields surrounding a static fermion contains both a ground state and at least one stable excited state. To bypass the difficulties associated with dynamical fermions in a lattice chiral gauge theory we consider only static fermion sources in a quenched approximation, at fixed lattice spacing and couplings, and with a lattice action along the lines suggested long ago by Smit and Swift.

We investigate the phase transition of the four-dimensional single-component ${\varphi }^4$ theory on the lattice using the tensor renormalization group method. We have examined the hopping parameter dependence of the bond energy and the vacuum condensation of the scalar field $⟨\varphi ⟩$ at a finite quartic coupling $\lambda$ on large volumes up to $V=1024^4$ in order to detect the spontaneous breaking of the ${\mathbb{Z}}_2$ symmetry. Our results show that the system undergoes the weak first-order phase transition at a certain critical value of the hopping parameter. We also make a comparative study of the three-dimensional ${\varphi }^4$ theory and find that the properties of the phase transition are consistent with the universality class of the three-dimensional Ising model.

We show how to compute electromagnetic polarizabilities of charged hadrons using four-point functions in lattice QCD. The low-energy behavior of Compton scattering amplitude is matched to matrix elements of current-current correlation functions on the lattice. Working in momentum space, formulas for electric polarizability (${\alpha }_E$) and magnetic polarizability (${\beta }_M$) are derived for both charged pion and proton. Lattice four-point correlation functions are constructed from quark and gluon fields to be used in Monte Carlo simulations. The content of the functions is assessed in detail, and specific prescriptions are given to isolate the polarizabilities. The connected quark-line diagrams can be done today as a small lattice project. The disconnected diagrams are more challenging but are within reach of dedicated resources for medium to large lattice projects. We also draw attention to the potential of four-point functions as a multipurpose tool for hadron structure.

We revisit the experimental and theoretical status of $B\to \rho l\overline{\nu }$ and $B\to \omega l\overline{\nu }$ decays. We perform a combined fit of averaged spectra from Belle and BABAR measurements with prior light-cone sum rule calculations in order to obtain more precise predictions over the full $q^2$ range. The extracted values of $|V_{ub}|$ from these combined fits exhibit smaller uncertainty compared to previous extractions from $B\to \rho l\overline{\nu }$ and $B\to \omega l\overline{\nu }$ decays, and the central values are found to be smaller than values extracted from $B\to \pi l\overline{\nu }$ or inclusive measurements. We use our fit results to obtain more precise predictions in and beyond the Standard Model for the lepton universality ratios $R(\rho )$ and $R(\omega )$, as well as several angular observables that are sensitive to the full $q^2$ distribution, such as the longitudinal polarization of the vector meson, the $\tau$ polarization, and its forward-backward asymmetry.

We evaluate the cross section for the $pp\to pp{f}_1(1285)$ and $p\overline{p}\to p\overline{p}{f}_1(1285)$ reactions at near threshold energies relevant for the HADES and PANDA experiments at GSI-FAIR. We assume that at energies close to the threshold the $\omega \omega \to f_1(1285)$ and ${\rho }^0{\rho }^0\to f_1(1285)$ fusion processes are the dominant production mechanisms. The vertex for the $VV\to f_1$ coupling is derived from an effective coupling Lagrangian. The $g_{\rho \rho f_1}$ coupling constant is extracted from the decay rate of $f_1(1285)\to {\rho }^0\gamma$ using the vector-meson-dominance ansatz. We assume $g_{\omega \omega f_1}=g_{\rho \rho f_1}$, equality of these two coupling constants, based on arguments from the naive quark model and vector-meson dominance. The amplitude for the $VV\to f_1$ fusion, supplemented by phenomenological vertex form factors for the process, is given. The differential cross sections at energies close to the threshold are calculated. In order to determine the parameters of the model the $\gamma p\to f_1(1285)p$ reaction is discussed in addition and results are compared with the CLAS data. The possibility of a measurement by HADES@GSI is presented and discussed. We perform a Monte Carlo feasibility simulation of the $pp\to pp{f}_1$ reaction for $\sqrt{s}=3.46\mathrm{GeV}$ with the $f_1$ decaying into the ${\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ (not shown explicitly) and ${\pi }^{+}{\pi }^{-}\eta (\to {\pi }^{+}{\pi }^{-}{\pi }^0)$ final states using the PLUTO event generator. The latter $f_1$ decay is especially promising as a peak in the ${\pi }^{+}{\pi }^{-}\eta$ mass distribution should be observable by HADES.

We compute the logarithmic contributions to the polarized massive Wilson coefficients for deep-inelastic scattering in the asymptotic region $Q^2\gg m^2$ to three-loop order in the fixed-flavor number scheme and present the corresponding expressions for the polarized massive operator matrix elements needed in the variable flavor number scheme. The calculation is performed in the Larin scheme. For the massive operator matrix elements $A_{qq,Q}^{(3),\mathrm{PS}}$ and $A_{qg,Q}^{(3),\mathrm{S}}$ the complete results are presented. The expressions are given in Mellin-$N$ space and in momentum fraction $z$ space.

In the framework of the Standard Model (SM) a theoretical description of the neutron beta decay is given at the level of ${10}^{-5}$. The neutron lifetime and correlation coefficients of the neutron beta decay for a polarized neutron, a polarized electron, and an unpolarized proton are calculated at the account for (i) the radiative corrections (RC) of order $O(\alpha E_e/m_N)\sim {10}^{-5}$, i.e., $O(\alpha E_e/m_N)$ RC, to Sirlin’s outer and inner $O(\alpha /\pi )$ RC, where $\alpha$ and $E_e$ are the fine-structure constant and the electron energy, respectively; (ii) the outer $O(\alpha E_e/m_N)$ RC, caused by Sirlin’s outer $O(\alpha /\pi )$ RC and the phase-volume of the neutron beta decay, calculated to next-to-leading order in the large nucleon mass $m_N$ expansion; (iii) the corrections of order $O(E_e^2/m_N^2)\sim {10}^{-5}$, caused by weak magnetism and proton recoil; and (iv) Wilkinson’s corrections of order ${10}^{-5}$ [Wilkinson, Nucl. Phys. A377, 474 (1982)]. These corrections define the SM background of the theoretical description of the neutron beta decay at the level of ${10}^{-5}$, which is required by experimental searches of interactions beyond the SM with experimental uncertainties of a few parts of ${10}^{-5}$.

A measurement of the $CP$ asymmetry in $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ decays is reported, based on a data sample of proton-proton collisions collected by the LHCb experiment from 2015 to 2018, corresponding to an integrated luminosity of $6{\mathrm{fb}}^{-1}$. The flavor of the $D^0$ candidate is determined using the charge of the $D^{*\pm }$ meson, from which the decay is required to originate. The $D^0\to K^{+}{K}^{-}$ decay is used as a calibration channel. The time-integrated $CP$ asymmetry for the $D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0$ mode is measured to be ${\mathcal{A}}^{CP}(D^0\to K_{\mathrm{S}}^0{K}_{\mathrm{S}}^0)=(-3.1\pm 1.2\pm 0.4\pm 0.2)$, where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the $CP$ asymmetry of the calibration channel. This is the most precise determination of this quantity to date.

We present a Bayesian parameter-estimation pipeline to measure the properties of inspiralling stellar-mass black hole binaries with LISA. Our strategy (i) is based on the coherent analysis of the three noise-orthogonal LISA data streams, (ii) employs accurate and computationally efficient post-Newtonian waveforms—accounting for both spin-precession and orbital eccentricity—and (iii) relies on a nested sampling algorithm for the computation of model evidences and posterior probability density functions of the full 17 parameters describing a binary. We demonstrate the performance of this approach by analyzing the LISA Data Challenge (LDC–1) dataset, consisting of 66 quasicircular, spin-aligned binaries with signal-to-noise ratios ranging from 3 to 14 and times to merger ranging from 3000 to 2 years. We recover 22 binaries with signal-to-noise ratio higher than 8. Their chirp masses are typically measured to better than $0.02M_{\odot }$ at 90% confidence, while the sky-location accuracy ranges from 1 to 100 square degrees. The mass ratio and the spin parameters can only be constrained for sources that merge during the mission lifetime. In addition, we report on the successful recovery of an eccentric, spin-precessing source at signal-to-noise ratio 15 for which we can measure an eccentricity of $3\times {10}^{-3}$ and the time to merger to within $\sim 1\mathrm{hour}$.

Cosmic rays bombard the lunar surface producing mesons, which attenuate inside the regolith. They get slower and decay weakly into mostly sub-GeV neutrinos leaving the surface. Thus the Moon shines in neutrinos. Here we calculate spectra of low-energy neutrinos, which exhibit bright features potentially recognizable above isotropic neutrino background in the direction towards the Moon. Their observation, though a very challenging task for future neutrino large volume experiments, would make the Moon the nearest astrophysical source for which the concept of multimessenger astronomy truly works. Remarkably, some features of the lunar neutrino flux are sensitive to the surface mass density of the Moon.

We propose leveraging our proficiency for detecting Higgs resonances by using the Higgs as a tagging object for new heavy physics. In particular, we argue that searches for exotic Higgs production from decays of color-singlet fields with electroweak charges could beat current searches at the Large Hadron Collider which look for their decays to vectors. As an example, we study the production and decay of vectorlike leptons which admit Yukawa couplings with Standard Model leptons. We find that bounds from run 2 searches are consistent with anywhere from hundreds to many thousands of Higgses having been produced in their decays over the same period, depending on the representation. Dedicated searches for these signatures may thus be able to significantly improve our reach at the electroweak energy frontier.

Models of asymmetric dark matter (ADM) seek to explain the apparent coincidence between the present-day mass densities of visible and dark matter, ${\mathrm{\Omega }}_{\mathrm{DM}}\simeq 5{\mathrm{\Omega }}_{\mathrm{VM}}$. However, most ADM models only relate the number densities of visible and dark matter without motivating the similar particle masses. We expand upon a recent work that obtained a natural mass relationship in a mirror matter ADM model with two Higgs doublets in each sector, by looking to implement dark electroweak baryogenesis as the means of asymmetry generation. We explore two aspects of the mechanism: the nature of the dark electroweak phase transition, and the transfer of particle asymmetries between the sectors by the use of portal interactions. We find that both aspects can be implemented successfully for various regions of the parameter space. We also analyze one portal interaction—the neutron portal—in greater detail, in order to satisfy the observational constraints on dark radiation.

Supersymmetric grand unification based on $SO(10)$ is one of the most attractive paradigms in physics beyond the Standard Model. Inspired by the recent NANOGrav signal, we discuss the implications of detecting a stochastic gravitational wave background emitted by a network of cosmic strings for the $SO(10)$ grand unification. Starting from a minimal model with multiple steps of symmetry breaking, we show that it generally prefers a high intermediate scale above ${10}^{14}\mathrm{GeV}$ that is favored by observable primordial gravitational waves. The observed spectrum can potentially narrow the possible range of the cosmic string scale and restricts the unified couplings and the unification scale by requiring gauge coupling unification. As an indirect consequence of the high cosmic string scale, the monopole abundance places nontrivial constraints on the theory. These are complementary to the proton decay constraints and probe different facets of supersymmetric $SO(10)$ unification theories.

Clockwork models can explain the flavor hierarchies in the Standard Model quark and lepton spectrum. We construct supersymmetric versions of such flavor clockwork models. The zero modes of the clockwork are identified with the fermions and sfermions of the minimal supersymmetric Standard Model. In addition to generating a hierarchical fermion spectrum, the clockwork also predicts a specific flavor structure for the soft SUSY breaking sfermion masses. We find sizeable flavor mixing among first and second generation squarks. Constraints from kaon oscillations require the masses of either squarks or gluinos to be above a scale of $\sim 3\mathrm{PeV}$.

Motivated by renewed evidence for new physics in $b\to s\ell \ell$ transitions in the form of LHCb’s new measurements of theoretically clean lepton-universality ratios and the purely leptonic $B_s\to {\mu }^{+}{\mu }^{-}$ decay, we quantify the combined level of discrepancy with the Standard Model and fit values of short-distance Wilson coefficients. A combination of the clean observables $R_K$, $R_{K^{*}}$, and $B_s\to \mu \mu$ alone results in a discrepancy with the Standard Model at $4.0\sigma$, up from $3.5\sigma$ in 2017. One-parameter scenarios with purely left-handed or with purely axial coupling to muons fit the data well and result in a $\sim 5\sigma$ pull from the Standard Model. In a two-parameter fit of new-physics contributions with both vector and axial-vector couplings to muons the allowed region is much more restricted than in 2017, principally due to the much more precise result on $B_s\to {\mu }^{+}{\mu }^{-}$, which probes the axial coupling to muons. Including angular observables data restricts the allowed region further. A by-product of our analysis is an updated average of $\mathrm{BR}(B_s\to {\mu }^{+}{\mu }^{-})=(2.8\pm 0.3)\times {10}^{-9}$.

We derive partial-wave unitarity constraints on gauge-invariant interactions of an axionlike particle up to dimension-6 from all allowed $2\to 2$ scattering processes in the limit of large center-of-mass energy. We find that the strongest bounds stem from scattering amplitudes with one external axionlike particle and only apply to the coupling to a pair of $SU(2{)}_L$ gauge bosons. Couplings to $U(1{)}_Y$ and $SU(3{)}_C$ gauge bosons and to fermions are more loosely constrained.

The cross sections of $J/\psi {\eta }_c$ and $J/\psi J/\psi$ production in $e^{+}{e}^{-}$ annihilation are calculated at a one-loop accuracy near $Z$-boson pole and at higher energies as well. Both intermediate bosons, $\gamma$ and $Z$, are included. It is found that at $Z$ mass, the next-to-leading contribution increases the production cross sections by a factor of 3.5.