In this addendum to T. Becher and X. Garcia i Tormo, Phys. Rev. D 88, 013009 (2013), we give results for the electroweak Sudakov corrections in gauge-boson production at large transverse momentum $p_T$ at proton colliders. For the results to be easily usable, we provide a simple and accurate parametrization of the corrections as a function of $p_T$ and the center-of-mass energy $\sqrt{s}$. Additionally, we also discuss the dependence of the electroweak corrections on the rapidity of the produced boson and comment on the complications that arise in the photon-production case due to isolation requirements.

Two searches for physics beyond the standard model in events containing photons are presented. The data sample used corresponds to an integrated luminosity of $19.7{\mathrm{fb}}^{-1}$ of proton-proton collisions at $\sqrt{s}=8\mathrm{TeV}$, collected with the CMS experiment at the CERN LHC. The analyses pursue different inclusive search strategies. One analysis requires at least one photon, at least two jets, and a large amount of transverse momentum imbalance, while the other selects events with at least two photons and at least one jet, and uses the razor variables to search for signal events. The background expected from standard model processes is evaluated mainly from data. The results are interpreted in the context of general gauge-mediated supersymmetry, with the next-to-lightest supersymmetric particle either a bino- or wino-like neutralino, and within simplified model scenarios. Upper limits at the 95% confidence level are obtained for cross sections as functions of the masses of the intermediate supersymmetric particles.

Measurements of the branching ratios of top quark decays into leptons and jets using events with $t\overline{t}$ (top antitop) pairs are reported. Events were recorded with the ATLAS detector at the LHC in $pp$ collisions at a center-of-mass energy of 7 TeV. The collected data sample corresponds to an integrated luminosity of $4.6{\mathrm{fb}}^{-1}$. The measured top quark branching ratios agree with the Standard Model predictions within the measurement uncertainties of a few percent.

Using $2.92{\mathrm{fb}}^{-1}$ of electron-positron annihilation data collected at a center-of-mass energy of $\sqrt{s}=3.773\mathrm{GeV}$ with the BESIII detector, we present an improved measurement of the branching fraction $\mathcal{B}(D^{+}\to \omega e^{+}{\nu }_e)=(1.63\pm 0.11\pm 0.08)\times 10^{-3}$. The parameters defining the corresponding hadronic form factor ratios at zero momentum transfer are determined for the first time; we measure them to be $r_V=1.24\pm 0.09\pm 0.06$ and $r_2=1.06\pm 0.15\pm 0.05$. The first and second uncertainties are statistical and systematic, respectively. We also search for the decay $D^{+}\to \varphi e^{+}{\nu }_e$. An improved upper limit $\mathcal{B}(D^{+}\to \varphi e^{+}{\nu }_e)<1.3\times 10^{-5}$ is set at 90% confidence level.

We consider the propagation of electromagnetic waves through a dilaton-Maxwell domain wall of the type introduced by Gibbons and Wells [G. W. Gibbons and C. G. Wells, Classical and Quantum Gravity 11, 2499 (1994)]. It is found that if such a wall exists within our observable Universe, it would be absurdly thick, or else have a magnetic field in its core which is much stronger than observed intergalactic fields. We conclude that it is highly improbable that any such wall is physically realized.

We analyze various aspects of pion and kaon condensation in the framework of chiral perturbation theory. Considering a system at vanishing temperature and varying the isospin chemical potential and the strange quark chemical potential we reproduce known results about the phase transition to the pion condensation phase and to the kaon condensation phase. However, we obtain mesonic mixings and masses in the condensed phases that are in disagreement with the results reported in previous works. Our findings are obtained both by a theory group analysis and by direct calculation by means of the same low-energy effective Lagrangian used in previous works. We also study the leptonic decay channels in the normal phase and in the pion condensed phase, finding that some of these channels have a peculiar nonmonotonic behavior as a function of the isospin chemical potential. Regarding the semileptonic decays, we find that they are feeding processes for the stable charged pion state.

We demonstrate that ($3+1$)-dimensional quantum electrodynamics with fermionic charges, fermionic monopoles, and fermionic dyons arises at the edge of a ($4+1$)-dimensional gapped phase with short-range entanglement. The ground state of this phase cannot be adiabatically connected to a product state, even in the absence of any symmetry. Our construction provides independent evidence for the obstruction found by Wang et al. [Science 343, 629 (2014)] to a ($3+1$)-dimensional short-distance completion of all-fermion electrodynamics. The nontriviality of the bulk is demonstrated by a fermion number anomaly.

The development of hyperbolic formulations of Einstein’s equations has revolutionized our ability to perform long-time, stable, accurate numerical simulations of strong field gravitational phenomena. However, hyperbolic methods have seen relatively little application in one area of interest, type II critical collapse, where the challenges for a numerical code are particularly severe. Using the critical collapse of a massless scalar field in spherical symmetry as a test case, we study a generalization of the Baumgarte-Shapiro-Shibata-Nakamura formulation due to Brown that is suited for use with curvilinear coordinates. We adopt standard dynamical gauge choices, including 1+log slicing and a shift that is either zero or evolved by a Gamma-driver condition. With both choices of shift we are able to evolve sufficiently close to the black hole threshold to (1) unambiguously identify the discrete self-similarity of the critical solution, (2) determine an echoing exponent consistent with previous calculations, and (3) measure a mass scaling exponent, also in accord with prior computations. Our results can be viewed as an encouraging first step towards the use of hyperbolic formulations in more generic type II scenarios, including the as yet unresolved problem of critical collapse of axisymmetric gravitational waves.

Stationary and axially symmetric spacetimes play an important role in astrophysics, particularly in the theory of neutron stars and black holes. The static vacuum subclass of these spacetimes is known as Weyl’s class, and contains the Schwarzschild spacetime as its most prominent example. This paper is going to study the space of Killing tensor fields of valence 3 for spacetimes of Weyl’s class. Killing tensor fields play a crucial role in physics since they are in correspondence to invariants of the geodesic motion (i.e. constants of the motion). It will be proven that in static and axially symmetric vacuum spacetimes the space of Killing tensor fields of valence 3 is generated by Killing vector fields and quadratic Killing tensor fields. Using this result, it will be proven that for the family of Zipoy-Voorhees metrics, valence-3 Killing tensor fields are always generated by Killing vector fields and the metric.

The Einstein equations for an isotropic and homogeneous Friedmann-Robertson-Walker universe in the presence of a quintessence scalar field are shown to be described in a compact way, formally identical to the dynamics of a relativistic particle moving on a two-dimensional spacetime. The correct Lagrangian for the system is presented and used to construct a spinor quantum cosmology theory using Breit’s prescription. The theory is supersymmetric when written in the Majorana representation. The spinor field components interact through a potential that correlates the spacetime metric and the quintessence. An exact supersymmetric solution for $k=0$ case is exhibited. This quantum cosmology model may be interpreted as a theory of interacting universes.

One of the next frontiers in dark-matter direct-detection experiments is to explore the MeV to GeV mass regime. Such light dark matter does not carry enough kinetic energy to produce an observable nuclear recoil, but it can scatter off electrons, leading to a measurable signal. We introduce a semianalytic approach to characterize the resulting electron-scattering events in atomic and semiconductor targets, improving on previous analytic proposals that underestimate the signal at high recoil energies. We then use this procedure to study the time-dependent properties of the electron-scattering signal, including the modulation fraction, higher-harmonic modes and modulation phase. The time dependence can be distinct in a nontrivial way from the nuclear scattering case. Additionally, we show that dark-matter interactions inside the Earth can significantly distort the laboratory-frame phase-space distribution of sub-GeV dark matter.

The self-induced collapse hypothesis was introduced by D. Sudarsky and collaborators to explain the origin of cosmic structure from a perfect isotropic and homogeneous universe during the inflationary regime. In this paper, we calculate the power spectrum for the tensor modes, within the semiclassical gravity approximation, with the additional hypothesis of a generic self-induced collapse of the inflaton’s wave function; we also compute an estimate for the tensor-to-scalar ratio. Based on this calculation, we show that the considered proposal exhibits a strong suppression of the tensor modes amplitude; nevertheless, the corresponding amplitude is still consistent with the joint BICEP/KECK and Planck Collaboration’s limit on the tensor-to-scalar ratio.

We forecast the ability of cosmic microwave background (CMB) temperature and polarization data sets to constrain theories of eternal inflation using cosmic bubble collisions. Using the Fisher matrix formalism, we determine both the overall detectability of bubble collisions and the constraints achievable on the fundamental parameters describing the underlying theory. The CMB signatures considered are based on state-of-the-art numerical relativistic simulations of the bubble collision spacetime, evolved using the full temperature and polarization transfer functions. Comparing a theoretical cosmic-variance-limited experiment to the WMAP and Planck satellites, we find that there is no improvement to be gained from future temperature data, that adding polarization improves detectability by approximately 30%, and that cosmic-variance-limited polarization data offer only marginal improvements over Planck. The fundamental parameter constraints achievable depend on the precise values of the tensor-to-scalar ratio and energy density in (negative) spatial curvature. For a tensor-to-scalar ratio of 0.1 and spatial curvature at the level of $10^{-4}$, using cosmic-variance-limited data it is possible to measure the width of the potential barrier separating the inflating false vacuum from the true vacuum down to $M_{\text{Pl}}/500$, and the initial proper distance between colliding bubbles to a factor $\pi /2$ of the false vacuum horizon size (at three sigma). We conclude that very near-future data will have the final word on bubble collisions in the CMB.

We report calculations of cosmic-ray proton, nuclei, antiproton, electron and positron energy spectra within a “two-halo model” of diffusive transport. The two halos represent a simple, physically consistent generalization of the standard diffusion models, which assume a unique type of diffusion for cosmic rays in the whole galactic halo. We believe instead that cosmic rays may experience a smaller energy dependence of diffusion when they are in proximity of the galactic disk. Our scenario is supported by recent observations of cosmic ray protons, nuclei, anisotropy, and gamma-rays. We predict remarkably hard antiparticle spectra at high energy. In particular, at $E\gtrsim 10\mathrm{GeV}$, the antiproton/proton ratio is expected to flatten, while the positron fraction is found to increase with energy. We discuss the implications for cosmic-ray physics and dark matter searches via antimatter.

A recent proposal for explaining discrepancies in angular observables in the rare decay $B\to K^{*}{\mu }^{+}{\mu }^{-}$ with a gauged $L_{\mu }-L_{\tau }$ current carried with it the prediction of lepton flavor universality violation in related $B$-meson decays. This prediction gained empirical support with a subsequent hint for lepton flavor universality violation in the $B\to K{\ell }^{+}{\ell }^{-}$ decay by LHCb. In this short paper we fully quantify the prediction including the associated uncertainties. We also provide new predictions for a variety of additional observables sensitive to lepton flavor universality violation in $B$-meson decays.

We study the quantization of a minimally gauged massless Rarita–Schwinger field, by both the Dirac bracket and functional integral methods. The Dirac bracket approach in the covariant radiation gauge leads to an anticommutator that has a nonsingular limit as gauge fields approach zero, is manifestly positive semidefinite, and is Lorentz invariant. The constraints also have the form needed to apply the Faddeev–Popov method for deriving a functional integral, using the same constrained Hamiltonian and inverse constraint matrix that appear in the Dirac bracket approach.

We show that, in contrast to known results in the massive case, a minimally gauged massless Rarita–Schwinger field yields a consistent classical theory, with a generalized fermionic gauge invariance realized as a canonical transformation. To simplify the algebra, we study a two-component left chiral reduction of the massless theory. We formulate the classical theory in both Lagrangian and Hamiltonian form for a general non-Abelian gauging and analyze the constraints and the Rarita–Schwinger gauge invariance of the action. An explicit wave front calculation for Abelian gauge fields shows that wavelike modes do not propagate with superluminal velocities. An analysis of Rarita–Schwinger spinor scattering from gauge fields shows that adiabatic decoupling fails in the limit of zero gauge field amplitude, invalidating various “no-go” theorems based on “on-shell” methods that claim to show the impossibility of gauging Rarita–Schwinger fields. Quantization of Rarita–Schwinger fields, using many formulas from this paper, is taken up in the following paper.

The single-particle content of two-dimensional adjoint QCD remains elusive due to the inability to distinguish single- from multiparticle states. To find a criterion we compare several approximations to the theory. The starting point is a Hamiltonian containing only operators corresponding to the long-range Coulomb forces. This enables us to construct sets of eigenfunctions in the lowest parton sectors. A perturbative treatment of the omitted operators is then performed. We find that multiparticle states are absent if pair production is disallowed and hints for a double “Regge” trajectory of single-particle states. We discuss the structure of the eigensystem of the theory, and present the reason for the fact that bosonic single-particle states do not form multiparticle states.

The complex Langevin method in conjunction with the gauge cooling is applied to the two-dimensional lattice $SU(2)$ Yang-Mills theory that is analytically solvable. We obtain strong numerical evidence that at large Langevin time the expectation value of the plaquette variable converges, but to a wrong value when the complex phase of the gauge coupling is large.