We present an exact solution to the equations of massive gravity that displays cosmological constantlike behavior for any spherically symmetric distribution of matter, including arbitrary time dependence. On this solution, the new degrees of freedom from the massive graviton generate a cosmological constantlike contribution to stress energy that does not interact directly with other matter sources. When the effective cosmological constant contribution dominates over other sources of stress energy, the cosmological expansion self-accelerates, even when no other dark-energy-like ingredients are present. The new degrees of freedom introduced by giving the graviton the mass do not respond to arbitrarily large radial or homogeneous perturbations from other matter fields on this solution. We comment on possible implications of this result.

Radiative decays of bottomonium are revisited, focusing on contributions from higher-order relativistic effects. The leading relativistic correction to the magnetic spin-flip operator at the photon vertex is found to be particularly important. The combination of $\mathcal{O}(v^6)$ effects in the nonrelativistic QCD action and in the transition operator moves previous lattice results for excited ${\rm Y}$ decays into agreement with experiment.

We explore the consequences of heavy quark spin symmetry for the charmed meson-antimeson system in a contact-range (or pionless) effective field theory. As a trivial consequence, we theorize the existence of a heavy quark spin symmetry partner of the $X(3872)$, with $J^{\mathrm{PC}}=2^{++}$, which we call $X(4012)$ in reference to its predicted mass. If we additionally assume that the $X(3915)$ is a $0^{++}$ heavy spin symmetry partner of the $X(3872)$, we end up predicting a total of six $D^{(*)}{\overline{D}}^{(*)}$ molecular states. We also discuss the error induced by higher order effects such as finite heavy quark mass corrections, pion exchanges and coupled channels, allowing us to estimate the expected theoretical uncertainties in the position of these new states.

We show that quadratic divergences in top-quark condensation are cancelled when the tadpoles cancel. This latter cancellation is naturally implemented as the cancellation among the top-quark, Goldstone and Higgs contributions. We also calculate the bosonic correction terms to Gribov’s mass formula for the Higgs boson. These reduce the prediction for $M_H$ from 167 to 132 GeV. The tadpole cancellation condition by itself is an independent condition on the mass of the Higgs boson which, in Gribov’s $\mathrm{U}(1{)}_Y$ scenario, yields $M_H\approx 117\mathrm{GeV}$ with large theoretical uncertainty. More generally, we are able to obtain all three masses, $M_W$, $m_t$ and $M_H$, in the 100 GeV to 10 TeV energy range as a function of the cutoff scale and the gauge couplings only.

There are several ways to explain the dark matter relic density other than by the ordinary freeze-out scenario. For example, the freeze-in mechanism may constitute an alternative for generating the correct relic density for dark matter candidates whose predicted freeze-out abundance is too low due to a large total annihilation cross section. Here we show that although such a mechanism could explain why a dark matter candidate has the correct relic density, some candidates may still be ruled out because they would lead to a large gamma-ray flux in dwarf spheroidal galaxies or a large elastic scattering rate in direct detection experiments. To investigate this scenario we examine neutralino dark matter in the MSSM. However, our conclusions can be generalized to other types of annihilating DM candidates with a low relic density in the freeze-out scenario, but which have their relic densities generated by some other mechanism.

Dynamical dark matter (DDM) is an alternative framework for dark-matter physics in which the dark-matter candidate is an ensemble of constituent fields with differing masses, lifetimes, and cosmological abundances. In this framework, it is the balancing of these quantities against each other across the ensemble as a whole which ensures phenomenological viability. In this paper, we examine the prospects for the direct detection of a DDM ensemble. In particular, we study the constraints imposed by current limits from direct-detection experiments on the parameter space of DDM models, and we assess the prospects for detecting such an ensemble and distinguishing it from traditional dark-matter candidates on the basis of data from the next generation of direct-detection experiments. For concreteness, we focus primarily on the case in which elastic scattering via spin-independent interactions dominates the interaction rate between atomic nuclei and the constituent particles of the ensemble. We also briefly discuss the effects of modifying these assumptions.

We simulate $K\pi$ scattering in $s$ wave and $p$ wave for both isospins $I=1/2$, $3/2$ using quark-antiquark and meson-meson interpolating fields. We extract the elastic phase shifts $\delta$ at several values of the $K\pi$ relative momenta. The resulting phases exhibit qualitative agreement with the experimental phases in all four channels. We express the $s$-wave phase shifts near threshold in terms of the scattering length and the effective range. Our $K\pi$ system has zero total momentum and is simulated on a single ensemble with two dynamical quarks, so results apply for $m_{\pi }\simeq 266\mathrm{MeV}$ and $m_K\simeq 552\mathrm{MeV}$ in our simulation. The backtracking contractions in both $I=1/2$ channels are handled by the use of Laplacian-Heavyside smeared quarks within the distillation method. Elastic phases are extracted from the energy levels using Lüscher’s relations. In all four channels, we observe the expected $K(n)\pi (-n)$ scattering states, which are shifted due to the interaction. In both attractive $I=1/2$ channels, we observe additional states which are related to resonances; we attribute them to $K_0^{*}(1430)$ in $s$ wave and $K^{*}(892)$, $K^{*}(1410)$ and $K^{*}(1680)$ in $p$ wave.

Quantum chromodynamics (QCD) at nonzero isospin chemical potential is studied in a canonical approach by analyzing systems of fixed isospin number density. To construct these systems, we develop a range of new algorithms for performing the factorially large numbers of Wick contractions required in multihadron systems. We then use these methods to study systems with the quantum numbers of up to $72{\pi }^{+}$’s on three ensembles of gauge configurations with spatial extents $L\sim 2.0$, 2.5 and 3.0 fm, and light quark masses corresponding to a pion mass of 390 MeV. The ground state energies of these systems are extracted and the volume dependence of these energies is utilized to determine the two- and three-body interactions among ${\pi }^{+}$’s. The systems studied correspond to isospin densities of up to ${\rho }_I\sim 9{\mathrm{fm}}^{-3}$ and probe isospin chemical potentials, ${\mu }_I$, in the range $m_{\pi }\lesssim {\mu }_I\lesssim 4.5m_{\pi }$, allowing us to investigate aspects of the QCD phase diagram at low temperature and for varying isospin chemical potential. By studying the energy density of the system, we provide numerical evidence for the conjectured transition of the system to a Bose-Einstein condensed phase at ${\mu }_I\gtrsim m_{\pi }$.

We study infrared conformality of the twelve-flavor QCD on the lattice. Utilizing the highly improved staggered quarks (HISQ) type action which is useful to study continuum physics, we analyze the lattice data of the mass and the decay constant of a pseudoscalar meson and the mass of a vector meson as well at several values of lattice spacing and fermion mass. Our result is consistent with the conformal hypothesis for the mass anomalous dimension ${\gamma }_m\sim 0.4–0.5$.

We present a general relativistic framework for the calculation of the electroweak structure of heavy-light mesons within constituent-quark models. To this aim the physical processes in which the structure is measured, i.e., electron-meson scattering and semileptonic weak decays, are treated in a Poincaré-invariant way by making use of the point form of relativistic quantum mechanics. The electromagnetic and weak meson currents are extracted from the $1\mathrm{\text{−}}\gamma$- and $1\mathrm{\text{−}}W$-exchange amplitudes that result from a Bakamjian-Thomas type mass operator for the respective systems. The covariant decomposition of these currents provides the electromagnetic and weak (transition) form factors. Problems with cluster separability, which are inherent in the Bakamjian-Thomas construction, are discussed and it is shown how to keep them under control. It is proved that the heavy-quark limit of the electroweak form factors leads to one universal function, the Isgur-Wise function, confirming that the requirements of heavy-quark symmetry are satisfied. A simple analytical expression is given for the Isgur-Wise function and its agreement with a corresponding front-form calculation is verified numerically. Electromagnetic form factors for $B^{-}$ and $D^{+}$ and weak $B\to D^{(*)}$ decay form factors are calculated with a simple harmonic-oscillator wave function and heavy-quark symmetry breaking due to finite masses of the heavy quarks is discussed.

Light sterile neutrinos mixing with the active ones have been recently proposed to solve different anomalies observed in short-baseline oscillation experiments. These neutrinos can also be produced by oscillations of the active neutrinos in the early Universe, leaving possible traces on different cosmological observables. Here, we perform an updated study of the neutrino kinetic equations in ($3+1$) and ($2+1$) oscillation schemes, dynamically evolving primordial asymmetries of active neutrinos and taking into account for the first time $CP$-violation effects. In the absence of neutrino asymmetries, eV-mass scale sterile neutrinos would be completely thermalized, creating a tension with respect to the cosmic microwave background, large scale structures, and big bang nucleosynthesis data. In the past literature, active neutrino asymmetries have been invoked as a way to inhibit the sterile neutrino production via the in-medium suppression of the sterile-active mixing angle. However, neutrino asymmetries also permit a resonant sterile neutrino production. We find that if the active species have equal asymmetries $L$, a value $|L|={10}^{-3}$ is required to start suppressing the resonant sterile production, roughly an order of magnitude larger than what was previously expected. When active species have opposite asymmetries, the sterile abundance is further enhanced, requiring an even larger $|L|\simeq {10}^{-2}$ to start suppressing their production. In the latter case, $CP$ violation (naturally expected) further exacerbates the phenomenon. Some consequences for cosmological observables are briefly discussed: for example, it is likely that moderate suppressions of the sterile species production are associated with significant spectral distortions of the active neutrino species, with potentially interesting phenomenological consequences especially for big bang nucleosynthesis.

This paper reports measurements of atmospheric neutrino and antineutrino interactions in the MINOS Far Detector, based on 2553 live-days (37.9 kton-years) of data. A total of 2072 candidate events are observed. These are separated into 905 contained-vertex muons and 466 neutrino-induced rock-muons, both produced by charged-current ${\nu }_{\mu }$ and ${\overline{\nu }}_{\mu }$ interactions, and 701 contained-vertex showers, composed mainly of charged-current ${\nu }_e$ and ${\overline{\nu }}_e$ interactions and neutral-current interactions. The curvature of muon tracks in the magnetic field of the MINOS Far Detector is used to select separate samples of ${\nu }_{\mu }$ and ${\overline{\nu }}_{\mu }$ events. The observed ratio of ${\overline{\nu }}_{\mu }$ to ${\nu }_{\mu }$ events is compared with the Monte Carlo (MC) simulation, giving a double ratio of $R_{\overline{\nu }/\nu }^{\mathrm{data}}/R_{\overline{\nu }/\nu }^{\mathrm{MC}}=1.03\pm 0.08(\mathrm{stat})\pm 0.08(\mathrm{syst})$. The ${\nu }_{\mu }$ and ${\overline{\nu }}_{\mu }$ data are separated into bins of $L/E$ resolution, based on the reconstructed energy and direction of each event, and a maximum likelihood fit to the observed $L/E$ distributions is used to determine the atmospheric neutrino oscillation parameters. This fit returns 90% confidence limits of $|\Delta m^2|=(1.9\pm 0.4)\times {10}^{-3}{\mathrm{eV}}^2$ and ${sin}^{2}2\theta >0.86$. The fit is extended to incorporate separate ${\nu }_{\mu }$ and ${\overline{\nu }}_{\mu }$ oscillation parameters, returning 90% confidence limits of $|\Delta m^2|-|\Delta {\overline{m}}^2|={0.6}_{-0.8}^{+2.4}\times {10}^{-3}{\mathrm{eV}}^2$ on the difference between the squared-mass splittings for neutrinos and antineutrinos.

The decay ${\overline{B}}_s^0\to J/\psi {\pi }^{+}{\pi }^{-}$ can be exploited to study $CP$ violation. A detailed understanding of its structure is imperative in order to optimize its usefulness. An analysis of this three-body final state is performed using a $1.0{\mathrm{fb}}^{-1}$ sample of data produced in 7 TeV $pp$ collisions at the LHC and collected by the LHCb experiment. A modified Dalitz plot analysis of the final state is performed using both the invariant mass spectra and the decay angular distributions. The ${\pi }^{+}{\pi }^{-}$ system is shown to be dominantly in an $S$-wave state, and the $CP$-odd fraction in this ${\overline{B}}_s^0$ decay is shown to be greater than 0.977 at 95% confidence level. In addition, we report the first measurement of the $J/\psi {\pi }^{+}{\pi }^{-}$ branching fraction relative to $J/\psi \varphi$ of $(19.79\pm 0.47\pm 0.52)\%$.

We update the comparison with an experiment of the dynamical model of high-energy hadron interactions based on the two-scale structure of hadrons. All predictions made over a decade ago are confirmed with a high precision by the TOTEM experiment at LHC.

Solar and atmospheric neutrino oscillations are consistent with a tribimaximal form of the mixing matrix $U$ of the lepton sector. Exact tribimaximal mixing leads to ${\theta }_{13}=0$. Recent results from the Daya Bay and RENO experiments have established a nonzero value of ${\theta }_{13}$. Keeping the leading behavior of $U$ as tribimaximal we perform a model-independent perturbative calculation to incorporate a nonvanishing ${\theta }_{13}$. We identify the nature of the perturbation matrix and consider the possibility of the solar neutrino splitting also resulting from it. We calculate up to first order in perturbation theory and evaluate the deviations proportional to $\sin {\theta }_{13}$ while including $CP$ nonconservation. Finally, we briefly discuss a gauge model where such an addition to the neutrino mass matrix arises through one-loop effects.

Several proposals to deal with the dynamics of general relativity involve gauge fixings or the introduction of matter fields in terms of which the theory is deparametrized. The resulting theories have true Hamiltonians for their evolution that usually involve square roots, and this poses certain challenges for their implementation as self-adjoint quantum operators. We show in the context of a simple model of a totally constrained theory that one can introduce related, well-defined operators that reproduce semiclassically the same physics as the original ones, at least for states peaked in the regions of phase space where their associated classical quantities are well-defined.

Maximally helicity-violating (MHV) diagrams give an efficient Feynman diagramlike formalism for calculating gauge theory scattering amplitudes on momentum space. Although they arise as the Feynman diagrams from an action on twistor space in an axial gauge, the main ingredients were previously expressed only in momentum space and momentum twistor space. Here we show how the formalism can be elegantly derived and expressed entirely in twistor space. This brings out the underlying superconformal invariance of the framework (up to the choice of a reference twistor used to define the axial gauge) and makes the twistor support transparent. Our treatment is largely independent of signature, although we focus on Lorentz signature. Starting from the $\mathcal{N}=4$ super-Yang-Mills twistor action, we obtain the propagator for the antiholomorphic Dolbeault operator as a delta function imposing collinear support with the reference twistor defining the axial gauge. The MHV vertices are also expressed in terms of similar delta functions. We obtain concrete formulas for tree-level ${\mathrm{N}}^k\mathrm{MHV}$ diagrams as a product of MHV amplitudes with an R invariant for each propagator; here the R invariant manifests superconformal as opposed to dual-superconformal invariance. This gives the expected explicit support on $k+1$ lines linked by $k$ further lines associated to the propagators. The R invariants arising correspond to those obtained in the dual conformal invariant momentum twistor version of the formalism, but differences arise in the specification of the boundary terms. Surprisingly, in this framework, some finite loop integrals can be performed as simply as those for tree diagrams.

We present an efficient separable approach to the estimation and reconstruction of the bispectrum and the trispectrum from observational (or simulated) large-scale structure data. This is developed from general cosmic microwave background (poly)spectra methods that exploit the fact that the bispectrum and trispectrum in the literature can be represented by a separable mode expansion that converges rapidly (with $n_{\max }=\mathcal{O}(30)$ terms). The underlying methodology can encompass a wide variety of modal types, including polynomials, trigonometric functions, wavelets, and bins. With an effective grid resolution $l_{\max }$ (number of particles/grid points $N=l_{\max }^3$), we present a bispectrum estimator that requires only $\mathcal{O}(n_{\max }\times l_{\max }^3)$ operations, along with a corresponding method for direct bispectrum reconstruction. This method is extended to the trispectrum revealing an estimator that requires only $\mathcal{O}(n_{\max }^{4/3}\times l_{\max }^3)$ operations. The complexity in calculating the trispectrum in this method is now involved in the original decomposition and orthogonalization process that need only be performed once for each model. However, for nondiagonal trispectra these processes present little extra difficulty and may be performed in $\mathcal{O}(l_{\max }^4)$ operations. A discussion of how the methodology may be applied to the quadspectrum is also given. An efficient algorithm for the generation of arbitrary non-Gaussian initial conditions for use in N-body codes using this separable approach is described. This prescription allows for the production of non-Gaussian initial conditions for arbitrary bispectra and trispectra. A brief outline of the key issues involved in parameter estimation, particularly in the nonlinear regime, is also given.

Using the general results on the classification of timelike supersymmetric solutions of all four-dimensional $\mathcal{N}\ge 2$ supergravity theories, we show how to construct all the supersymmetric (single- and multi-) black-hole solutions of $\mathcal{N}=8$ supergravity.

We correct Eq. (10) for deep inelastic scattering (DIS) through QCD instantons and its longitudinal as well as transverse projections. For the single spin asymmetries (SSA) in DIS with longitudinal polarizations, the corrected results fit better the reported data, while for the transversely polarized protons the results are larger than the experimentally reported data.