We investigate the implications of a putative new resonance in the TeV region coupled to the weak bosons. By studying perturbative unitarity of longitudinal $WW$ scattering, we find that a weakly coupled spin-1 resonance, that explains the ATLAS diboson excesses, is allowed with a SM-like Higgs. On the other hand, larger values of the resonance couplings, preferred in models of strong dynamics, would imply either sizeable reduction of the Higgs couplings or new physics, beyond the diboson resonance, at a few TeV.

Dark matter (DM) without a matter asymmetry is studied in the context of twin Higgs (TH) theories in which the LHC naturalness problem is addressed. These possess a twin sector related to the Standard Model (SM) by a (broken) ${\mathbb{Z}}_2$ symmetry, and interacting with the SM via a specific Higgs portal. We focus on the minimal realization of the TH mechanism, the fraternal twin Higgs, with only a single generation of twin quarks and leptons, and the $SU(3{)}^{\prime }\times SU(2{)}^{\prime }$ gauge group. We show that a variety of natural twin-WIMP DM candidates are present (directly linked to the weak scale by naturalness), the simplest and most attractive being the ${\tau }^{\prime }$ lepton with a mass $m_{{\tau }^{\prime }}>m_{\text{Higgs}}/2$, although spin-1 $W^{\prime \pm }$ DM and multicomponent DM are also possible (twin baryons are strongly disfavored by tuning). We consider in detail the dynamics of the possibly (meta)stable glueballs in the twin sector, the nature of the twin QCD phase transition, and possible new contributions to the number of relativistic degrees of freedom, $\mathrm{\Delta }{N}_{\mathrm{eff}}$. Direct detection signals are below current bounds but accessible in near-future experiments. Indirect detection phenomenology is rich and requires detailed studies of twin hadronization and fragmentation to twin glueballs and quarkonia and their subsequent decay to SM, and possible light twin sector states.

We propose a focus point gauge mediation model based on the product group unification (PGU), which solves the doublet-triplet splitting problem of the Higgs multiplets. In the focus point gauge mediation, the electroweak symmetry breaking scale can be naturally explained even for multi-TeV stops. It is known that the focus point behavior appears if a ratio of the number of $SU(2)$ doublet messengers to that of $SU(3)$ triplet messengers is close to $5/2$. Importantly, this ratio (effectively) appears in our scenario based on the PGU, if the messenger field is an adjoint representation of the $SU(5)$ gauge group. Therefore, our focus point scenario is very predictive. It is also pointed out that the gravitino can be dark matter without spoiling the success of the thermal leptogenesis.

Recent developments showed that light-cone parton distributions can be studied by investigating the large momentum limit of the so-called quasiparton distributions, which are defined in terms of spacelike correlators, and therefore can be readily computed on the lattice. These two distributions can be connected to each other by a perturbative factorization formula or matching condition that allows one to convert the latter into the former. Here we present the one-loop matching condition for the transversity generalized quark distribution in the nonsinglet case.

The direct $CP$ asymmetry $a_{CP}^{\text{dir}}(D^0\to K_S{K}_S)$ involves exchange diagrams which are induced at tree level in the Standard Model. Since the corresponding topological amplitude $E_{KK}$ can be large, $D^0\to K_S{K}_S$ is a promising discovery channel for charm $CP$ violation. We estimate the penguin annihilation amplitude with a perturbative calculation and extract the exchange amplitude $E_{KK}$ from a global fit to $D$ branching ratios. Our results are further used to predict the size of mixing-induced $CP$ violation. We obtain $|a_{CP}^{\text{dir}}(D^0\to K_S{K}_S)|\le 1.1\%$ (95% C.L.). The same bound applies to the nonuniversal part of the phase between the $D-\overline{D}$ mixing and decay amplitudes. If future data exceed our predictions, this will point to new physics or an enhancement of the penguin annihilation amplitude by QCD dynamics. We briefly discuss the implications of these possibilities for other $CP$ asymmetries.

This erratum serves to give corrections of two errors made in Koksbang and Hannestad [Phys. Rev. D, 92, 023532 (2015)]. One error consists of having used the expression for the Doppler convergence for a flat background to study the convergence on curved backgrounds. The other error which was made, is a typo in the numerical code used to study the convergence in onion models with curved backgrounds. After correcting this typo, the results of Sec. VI A in Koksbang and Hannestad [Phys. Rev. D, 92, 023532 (2015)] were recomputed. Contrary to the original results, the new results show that the ray-tracing scheme studied in Koksbang and Hannestad [Phys. Rev. D, 92, 023532 (2015)] can reproduce the exact results in LTB onion models very well. The corrections and new results are described more elaborately below.

We study how the kinetic decoupling of dark matter within a minimal supersymmetric extension of the standard model, by adopting nine independent parameters (MSSM-9), could improve our knowledge of the properties of the dark matter protohalos. We show that the most probable neutralino mass regions, which satisfy the relic density and the Higgs mass constraints, are those with the lightest supersymmetric neutralino mass around 1 TeV and 3 TeV, corresponding to Higgsino-like and winolike neutralino, respectively. The kinetic decoupling temperature in the MSSM-9 scenario leads to a most probable protohalo mass in a range of $M_{\text{ph}}\sim {10}^{-12}–{10}^{-7}{M}_{\odot }$. The part of the region closer to $\sim 2\mathrm{TeV}$ gives also important contributions from the neutralino-stau coannihilation, reducing the effective annihilation rate in the early Universe. We also study how the size of the smallest dark matter substructures correlates to experimental signatures, such as the spin-dependent and spin-independent scattering cross sections, relevant for direct detection of dark matter. Improvements on the spin-independent sensitivity might reduce the most probable range of the protohalo mass between $\sim {10}^{-9}{M}_{\odot }$ and $\sim {10}^{-7}{M}_{\odot }$, while the expected spin-dependent sensitivity provides weaker constraints. We show how the boost of the luminosity due to dark matter annihilation increases, depending on the protohalo mass. In the Higgsino case, the protohalo mass is lower than the canonical value often used in the literature ($\sim {10}^{-6}{M}_{\odot }$), while $⟨\sigma v⟩$ does not deviate from $⟨\sigma v⟩\sim {10}^{-26}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$; there is no significant enhancement of the luminosity. On the contrary, in the wino case, the protohalo mass is even lighter, and $⟨\sigma v⟩$ is two orders of magnitude larger; as its consequence, we see a substantial enhancement of the luminosity.

In this article we extend a recent theorem proven by Hod [Upper bound on the radii of black-hole photon spheres, Phys. Lett. B 727, 345 (2013)] to $n$-dimensional Einstein and Einstein-Gauss-Bonnet theories, which gives an upper bound for the photon sphere radii of spherically symmetric black holes. As applications of these results we give a universal upper bound for the real part of quasinormal modes in the WKB limit and a universal lower bound for the position of the first relativistic image in the strong lensing regime produced by these type of black holes. For the axially-symmetric case, we also make some general comments (independent of the underlying gravitational theory) on the relation between circular null geodesics and the fastest way to circle a black hole.

The disformal transformation of metric $g_{\mu \nu }\to {\mathrm{\Omega }}^2(\varphi )g_{\mu \nu }+\mathrm{\Gamma }(\varphi ,X){\partial }_{\mu }\varphi {\partial }_{\nu }\varphi$, where $\varphi$ is a scalar field with the kinetic energy $X={\partial }_{\mu }\varphi {\partial }^{\mu }\varphi /2$, preserves the Lagrangian structure of Gleyzes–Langlois–Piazza–Vernizzi theories (which is the minimum extension of Horndeski theories). In the presence of matter, this transformation gives rise to a kinetic-type coupling between the scalar field $\varphi$ and matter. We consider the Einstein frame in which the second-order action of tensor perturbations on the isotropic cosmological background is of the same form as that in General Relativity and study the role of couplings at the levels of both background and linear perturbations. We show that the effective gravitational potential felt by matter perturbations in the Einstein frame can be conveniently expressed in terms of the sum of a General Relativistic contribution and couplings induced by the modification of gravity. For the theories in which the transformed action belongs to a class of Horndeski theories, there is no anisotropic stress between two gravitational potentials in the Einstein frame due to a gravitational demixing. We propose a concrete dark energy model encompassing Brans–Dicke theories as well as theories with the tensor propagation speed $c_{\mathrm{t}}$ different from 1. We clarify the correspondence between physical quantities in the Jordan/Einstein frames and study the evolution of gravitational potentials and matter perturbations from the matter-dominated epoch to today in both analytic and numerical approaches.

In the standard cosmological framework of the 0th-order Friedmann-Lemaître-Robertson-Walker (FLRW) metric and the use of perfect fluids in the stress-energy tensor, dark energy with an equation-of-state parameter $w<-1$ (known as phantom dark energy) implies negative kinetic energy and vacuum instability when modeled as a scalar field. However, the accepted values for present-day $w$ from Planck and WMAP9 include a significant range of values less than $-1$. We find that it is not as obvious as one might think that phantom dark energy has negative kinetic energy categorically. Analogously, we find that field models of quintessence dark energy ($w_{\varphi }>-1$) do not necessarily have positive kinetic energy categorically. Staying within the confines of observational constraints and general relativity, for which there is good experimental validation, we consider a few reasonable departures from the standard 0th-order framework in an attempt to see if negative kinetic energy can be avoided in these settings despite an apparent $w<-1$. We consider a more accurate description of the universe through the perturbing of the isotropic and homogeneous FLRW metric and the components of the stress-energy tensor, and we consider dynamic $w$ and primordial isocurvature and adiabatic perturbations. We find that phantom dark energy does not necessarily have negative kinetic energy for all relevant length scales at all times, and we also find that, by the same token, quintessence dark energy does not necessarily have positive kinetic energy for all relevant length scales at all times.

The presence of inhomogeneous phases in the QCD phase diagram is analyzed within chiral quark models that include nonlocal interactions. We work at the mean field level, assuming that the spatial dependence of scalar and pseudoscalar condensates is given by a dual chiral density wave. Phase diagrams for Gaussian nonlocal form factors are studied in detail and compared with those obtained within the Nambu—Jona-Lasinio model and quark-meson approaches.

We consider theories where dark matter is composed of a thermal relic of weak scale mass, whose couplings to the standard model (SM) are however too small to give rise to the observed abundance. Instead, the abundance is set by annihilation to light hidden sector states that carry no charges under the SM gauge interactions. In such a scenario the constraints from direct and indirect detection, and from collider searches for dark matter, can easily be satisfied. The masses of such light hidden states can be protected by symmetry if they are Nambu-Goldstone bosons, fermions, or gauge bosons. These states can then contribute to the cosmic energy density as dark radiation, leading to observable signals in the cosmic microwave background (CMB). Furthermore, depending on whether or not the light hidden sector states self-interact, the fraction of the total energy density that free-streams is either decreased or increased, leading to characteristic effects on both the scalar and tensor components of the CMB anisotropy that allows these two cases to be distinguished. The magnitude of these signals depends on the number of light degrees of freedom in the hidden sector, and on the temperature at which it kinetically decouples from the SM. We consider a simple model that realizes this scenario, based on a framework in which the SM and hidden sector are initially in thermal equilibrium through the Higgs portal, and show that the resulting signals are compatible with recent Planck results, while large enough to be detected in upcoming experiments such as CMBPol and CMB Stage-IV. Invisible decays of the Higgs into hidden sector states at colliders can offer a complementary probe of this model.

We propose an alternative evaluation of the long-distance weak annihilation (WA, also called one-photon exchange in this paper) contribution to the rare semileptonic $B^{\pm }\to ({\pi }^{\pm },K^{\pm }){\ell }^{+}{\ell }^{-}$ ($\ell =e,\mu$) decays. This hadronic description at low energies is matched at intermediate energies to its short-distance counterpart in terms of quark and gluon degrees of freedom. Although the WA contribution does not contribute to solve the possible breaking of lepton universality observed by LHCb in the $B^{\pm }\to K^{\pm }({\mu }^{+}{\mu }^{-}/e^{+}{e}^{-})$ ratio, nor does it provide an important hadronic contamination to their decay rates, its contribution to the branching ratios (and direct $CP$ asymmetry) of the $B^{\pm }\to {\pi }^{\pm }{\ell }^{+}{\ell }^{-}$ transitions turns out to be significant. This hadronic pollution should be taken into account when looking for new physics effects in decays into pions, which suggests to restrict these searches to squared lepton-pair invariant mass in the $(1,8){\mathrm{GeV}}^2$ range. The interference of the one-photon exchange contribution with the dominant short-distance one-loop amplitude induces a sizable $CP$ asymmetry in these rare decays, which calls for dedicated measurements.

The $B$-factories and Large Hadron Collider experiments have demonstrated the ability to observe and measure the properties of bottomonium mesons. In order to discover missing states it is useful to know their properties to develop a successful search strategy. To this end we calculate the masses and decay properties of excited bottomonium states. We use the relativized quark model to calculate the masses and wave functions and the ${{}^{3}P}_0$ quark-pair creation model to calculate decay widths to open bottom. We also summarize results for radiative transitions, annihilation decays, hadronic transitions and production cross sections which are used to develop strategies to find these states. We find that the $b\overline{b}$ system has a rich spectroscopy that we expect to be substantially extended by the LHC and $e^{+}{e}^{-}$ experiments in the near future. Some of the most promising possibilities at the LHC are observing the ${\chi }_{b(1,2)}(3P)$, ${\chi }_{b(1,2)}(4P)$ and ${\eta }_b(3S)$ states in $\gamma {\mu }^{+}{\mu }^{-}$ final states that proceed via radiative transitions through $\mathrm{\Upsilon }(nS)$ intermediate states and $1{{}^{3}D}_J$ and $2{{}^{3}D}_J$ into $\gamma \gamma {\mu }^{+}{\mu }^{-}$ final states proceeding via $1{{}^{3}P}_J\to 1{{}^{3}S}_1$ and $2{{}^{3}P}_J\to 2{{}^{3}S}_1$ intermediate states respectively. Some of the most interesting possibilities in $e^{+}{e}^{-}$ collisions are studying the $1{{}^{3}D}_J$ states via $4\gamma$ cascades starting with the $\mathrm{\Upsilon }(3S)$ and the $3{{}^{3}P}_J$ states in $\gamma \gamma {\mu }^{+}{\mu }^{-}$ final states starting with the $\mathrm{\Upsilon }(4S)$ and proceeding via $\mathrm{\Upsilon }(nS)$ intermediate states. Completing the bottomonium spectrum is an important validation of lattice QCD calculations and a test of our understanding of bottomonium states in the context of the quark model.

We calculate configuration energies of stringlike membranes in M2- and M5-brane spaces. In the near horizon approximation these backgrounds reduce to ${\mathrm{AdS}}_4\times S^7$ and ${\mathrm{AdS}}_7\times S^4$ spaces and the dual theories are supersymmetric $SU(N)$ gauge theories, in accordance with the AdS/CFT correspondence. In this case the stringlike configuration energy is identified with the quark and antiquark energy interaction in the dual theories. Far from the horizon the dual theory is more involved but anyhow we were able to calculate the stringlike configuration energy. For limiting regimes we find simpler solutions for which some potentials exhibit a confinement behavior while others are nonconfining.

We investigate the scalar and tensor spectral indices of the quadratic inflation model in Eddington-inspired Born-Infeld (EiBI) gravity. We find that the EiBI corrections to the spectral indices are of second and first order in the slow-roll approximation for the scalar and tensor perturbations, respectively. This is very promising since the quadratic inflation model in general relativity provides a very nice fit for the spectral indices. Together with the suppression of the tensor-to-scalar ratio, EiBI inflation is agrees well with the observational data.

Assuming that curvature perturbations and gravitational waves originally arise from vacuum fluctuations in a matter-dominated phase of contraction, we study the dynamics of the cosmological perturbations evolving through a nonsingular bouncing phase described by a generic single scalar field Lagrangian minimally coupled to Einstein gravity. In order for such a model to be consistent with the current upper limits on the tensor-to-scalar ratio, there must be an enhancement of the curvature fluctuations during the bounce phase. We show that, while it remains possible to enlarge the amplitude of curvature perturbations due to the nontrivial background evolution, this growth is very limited because of the conservation of curvature perturbations on super-Hubble scales. We further perform a general analysis of the evolution of primordial non-Gaussianities through the bounce phase. By studying the general form of the bispectrum we show that the non-Gaussianity parameter $f_{\mathrm{NL}}$ (which is of order unity before the bounce phase) is enhanced during the bounce phase if the curvature fluctuations grow. Hence, in such nonsingular bounce models with matter given by a single scalar field, there appears to be a tension between obtaining a small enough tensor-to-scalar ratio and not obtaining a value of $f_{\mathrm{NL}}$ in excess of the current upper bounds. This conclusion may be considered as a “no-go” theorem that rules out any single field matter bounce cosmology starting with vacuum initial conditions for the fluctuations.

Primordial fluctuations in the relative number densities of particles, or isocurvature perturbations, are generally well constrained by cosmic microwave background (CMB) data. A less probed mode is the compensated isocurvature perturbation (CIP), a fluctuation in the relative number densities of cold dark matter and baryons. In the curvaton model, a subdominant field during inflation later sets the primordial curvature fluctuation $\zeta$. In some curvaton-decay scenarios, the baryon and cold dark matter isocurvature fluctuations nearly cancel, leaving a large CIP correlated with $\zeta$. This correlation can be used to probe these CIPs more sensitively than the uncorrelated CIPs considered in past work, essentially by measuring the squeezed bispectrum of the CMB for triangles whose shortest side is limited by the sound horizon. Here, the sensitivity of existing and future CMB experiments to correlated CIPs is assessed, with an eye towards testing specific curvaton-decay scenarios. The planned CMB Stage 4 experiment could detect the largest CIPs attainable in curvaton scenarios with more than $3\sigma$ significance. The significance could improve if small-scale CMB polarization foregrounds can be effectively subtracted. As a result, future CMB observations could discriminate between some curvaton-decay scenarios in which baryon number and dark matter are produced during different epochs relative to curvaton decay. Independent of the specific motivation for the origin of a correlated CIP perturbation, cross-correlation of CIP reconstructions with the primary CMB can improve the signal-to-noise ratio of a CIP detection. For fully correlated CIPs the improvement is a factor of $\sim 2–3$.

We present results for the nucleon electromagnetic form factors, including the momentum transfer dependence and derived quantities (charge radii and magnetic moment). The analysis is performed using $\mathcal{O}(a)$ improved Wilson fermions in $N_f=2$ QCD measured on the Coordinated Lattice Simulations ensembles. Particular focus is placed on a systematic evaluation of the influence of excited states in three-point correlation functions, which lead to a biased evaluation, if not accounted for correctly. We argue that the use of summed operator insertions and fit Ansätze including excited states allow us to suppress and control this effect. We employ a novel method to perform joint chiral and continuum extrapolations, by fitting the form factors directly to the expressions of covariant baryonic chiral effective field theory. The final results for the charge radii and magnetic moment from our lattice calculations include, for the first time, a full error budget. We find that our estimates are compatible with experimental results within their overall uncertainties.