A detection of primordial B modes has been heralded not only as a smoking gun for the existence of inflation, but also as a way to establish the scale at which inflation took place. In this paper we critically reinvestigate the connection between a detection of primordial gravity waves and the scale of inflation. We consider whether the presence of additional fields and nonadiabaticity during inflation may have provided an additional source of primordial B modes competitive with those of the quasi–de Sitter vacuum. In particular, we examine whether the additional sources could provide the dominant signal, which could lead to a misinterpretation of the scale of inflation. In light of constraints on the level of non-Gaussianity coming from Planck we find that only hidden sectors with strictly gravitationally strong couplings provide a feasible mechanism. The required model building is somewhat elaborate, and so we discuss possible UV completions in the context of type IIB orientifold compactifications with Ramond-Ramond axions. We find that an embedding is possible and that dangerous sinusoidal corrections can be suppressed through the compactification geometry. Our main result is that even when additional sources of primordial gravity waves are competitive with the inflaton, a positive B-mode detection would still be a relatively good indicator of the scale of inflation. This conclusion will be strengthened by future constraints on both non-Gaussianity and cosmic microwave background polarization.

There is a tension between measurements of the amplitude of the power spectrum of density perturbations inferred using the cosmic microwave background (CMB) and directly measured by large-scale structure (LSS) on smaller scales. We show that this tension exists, and is robust, for a range of LSS indicators including clusters, lensing and redshift space distortions and using CMB data from either Planck or $\mathrm{WMAP}+\mathrm{SPT}/\mathrm{ACT}$. One obvious way to try to reconcile this is the inclusion of a massive neutrino which could be either active or sterile. Using Planck and a combination of all the LSS data we find that (i) for an active neutrino $\sum m_{\nu }=(0.357\pm 0.099)\mathrm{eV}$ and (ii) for a sterile neutrino $m_{\text{sterile}}^{\text{eff}}=(0.67\pm 0.18)\mathrm{eV}$ and $\mathrm{\Delta }{N}_{\text{eff}}=0.32\pm 0.20$. This is, however, at the expense of a degraded fit to Planck temperature data, and we quantify the residual tension at $2.5\sigma$ and $1.6\sigma$ for massive and sterile neutrinos, respectively. We also consider alternative explanations including a lower redshift for reionization that would be in conflict with polarization measurements made by WMAP and ad hoc modifications to the primordial power spectrum.

We report results of an experimental search for the intrinsic electric dipole moment of the electron (eEDM) using a solid-state technique. The experiment employs a paramagnetic, insulating gadolinium gallium garnet (GGG) that has a large magnetic response at low temperatures. The presence of the eEDM would lead to a small but nonzero magnetization as the GGG sample is subjected to a strong electric field. We search for the resulting Stark-induced magnetization with a sensitive magnetometer. Recent progress on the suppression of several sources of background allows the experiment to run free of spurious signals at the level of the statistical uncertainties. We report our first limit on the eEDM of $(-5.57\pm 7.98\pm 0.12)\times {10}^{-25}\mathrm{e}\mathrm{cm}$ with 5 days of data averaging.

We consider nonperturbative aspects of a composite Higgs model that serves as a prototype for physics beyond the Standard Model, in which a new strongly interacting sector undergoes chiral symmetry breaking, and generates the Higgs particle as a pseudo-Nambu-Goldstone boson. In addition, the top quark couples linearly to baryons of the new strong sector, thereby becoming partially composite. We study the dynamics leading to the top quark Yukawa coupling as well as the top quark contribution to the effective potential for the Higgs, obtaining expressions for these couplings in terms of baryonic correlation functions in the underlying strongly interacting theory. We then show that a large-$N$ limit exists in which the top quark contribution to the Higgs effective potential overcomes that of the weak gauge bosons, inducing electroweak symmetry breaking. The same large-$N$ limit also suggests that the baryons that couple to the top quark may be relatively light. This composite Higgs model, and similar ones, can be studied on the lattice with the methods developed for lattice QCD.

Based on previous studies that support the important role of the $f_2(1270)$, $f_2^{\prime }(1525)$, and ${\overline{K}}_2^{*}(1430)$ resonances in the $J/\psi [\psi (2S)]\to \varphi (\omega )VV$ decays, we make an analysis of the analogous decays of $\mathrm{\Upsilon }(1S)$ and $\mathrm{\Upsilon }(2S)$, taking into account recent experimental data. In addition, we study the $J/\psi$ and $\psi (2S)$ radiative decays and we also made predictions for the radiative decay of $\mathrm{\Upsilon }(1S)$ and $\mathrm{\Upsilon }(2S)$ into $\gamma f_2(1270)$, $\gamma f_2^{\prime }(1525)$, $\gamma f_0(1370)$ and $\gamma f_0(1710)$, comparing with the recent results of a CLEO experiment. We can compare our results for ratios of decay rates with eight experimental ratios and find agreement in all but one case, where experimental problems are discussed.

The relaxation times over which dissipative fluxes restore their steady-state values are evaluated for a pion gas using the 14-moment method. The effect of the medium is implemented through a temperature-dependent $\pi \pi$ cross section in the collision integral which is obtained by including one-loop self-energies in the propagators of the exchanged $\rho$ and $\sigma$ mesons. To account for chemical freeze-out in heavy-ion collisions, a temperature-dependent pion chemical potential is introduced in the distribution function. The temperature dependence of the relaxation times for shear and bulk viscous flows as well as the heat flow is significantly affected.

The deep inelastic scattering cross section in the endpoint region $x\sim 1$ has been subjected to extensive analysis. We revisit this process using soft collinear effective theory, and show that in the endpoint individual factors in the factorized hadronic tensor have rapidity divergences. We regulate these divergences using a recently introduced rapidity regulator, and find that each operator matrix element requires a different scale to minimize large rapidity logarithms. However, the running in rapidity is nonperturbative and must be absorbed into the definition of the parton distribution function.

Kinetic mixing between the metric and scalar degrees of freedom is an essential ingredient in contemporary scalar-tensor theories. This often makes it hard to understand their physical content, especially when derivative mixing is present, as is the case for Horndeski action. In this work we develop a method that allows us to write a Ricci-curvature-free scalar field equation, and we discuss some of the advantages of such a rephrasing in the study of stability issues in the presence of matter, the existence of an Einstein frame, and the generalization of the disformal screening mechanism. For quartic Horndeski theories, such a procedure leaves, in general, a residual coupling to the curvature, given by the Weyl tensor. This gives rise to a binary classification of scalar-tensor theories into stirred theories, in which the curvature can be substituted, and shaken theories, in which a residual coupling to the curvature remains. Quite remarkably, we have found that generalized Dirac-Born-Infeld Galileons belong to the first class. Finally, we discuss kinetic mixing in quintic theories, in which nonlinear mixing terms appear, and in the recently proposed theories beyond Horndeski that display a novel form of kinetic mixing, in which the field equation is sourced by derivatives of the energy-momentum tensor.

We present a new definition of the wormhole throat including the flare-out condition and the feature corresponding to the traversability for general dynamical spacetimes in terms of null geodesic congruences. We will examine our definition for some examples and see advantages compared to the others.

The bumblebee model of spontaneous Lorentz symmetry breaking is explored in a cosmological context, considering a single nonzero time component for the vector field. The relevant dynamic equations for the evolution of the Universe are derived and their properties and physical significance are studied. We conclude that a late-time de Sitter expansion of the Universe can be replicated, and attempt to constrain the parameter of the potential driving the spontaneous symmetry breaking.

A new approach to cosmological perturbation theory has been recently introduced by Bartelmann et al., relying on nonequilibrium statistical theory of classical particles, and treating the gravitational interaction perturbatively. They compute analytic expressions for the nonlinear matter power spectrum, to first order in the interaction, and at one-loop order in the linear power spectrum. The resulting power spectrum is well behaved even at large wave numbers and seems in good agreement with results from numerical simulations. In this paper, we rederive their results concisely with a different approach, starting from the implicit integral solution to particle trajectories. We derive the matter power spectrum to first order in the interaction, but to arbitrary order in the linear power spectrum, from which the one-loop result follows. We also show that standard linear perturbation theory can only be recovered at infinite order in the gravitational interaction. At finite order in the interaction, we find that the linear power spectrum is systematically and significantly underestimated. A comprehensive study of the convergence of the theory with the order of the interaction for nonlinear scales will be the subject of future work.

In the approach of the effective field theory of modified gravity, we derive the second-order action and the equation of motion for tensor perturbations on the flat isotropic cosmological background. This analysis accommodates a wide range of gravitational theories including Horndeski theories, its generalization, and the theories with spatial derivatives higher than second order (e.g., Hořava–Lifshitz gravity). We obtain the inflationary power spectrum of tensor modes by taking into account corrections induced by higher-order spatial derivatives and slow-roll corrections to the de Sitter background. We also show that the leading-order spectrum in concrete modified gravitational theories can be mapped on to that in General Relativity under a disformal transformation. Our general formula will be useful to constrain inflationary models from the future precise measurement of the B-mode polarization in the cosmic microwave background.

We present the first attempt to use a combination of CMB, LIGO, and Pulsar Timing Array (PPTA) data to constrain both the tilt and the running of primordial tensor power spectrum through constraints on the gravitational wave energy density generated in the early universe. Combining measurements at different cosmological scales highlights how complementary data can be used to test the predictions of early universe models including the inflationary consistency relation. Current data prefer a slightly positive tilt ($n_t=0.06_{-0.89}^{+0.63}$) and a negative running ($n_{t,\text{run}}<-0.22$) for the tensor power spectrum spectrum. Interestingly, the addition of direct gravitational wave detector data alone puts strong bounds on the tensor-to-scalar ratio $r<0.2$ since the large positive tensor tilt preferred by the Planck temperature power spectrum is no longer allowed. Adding the recently released BICEP2/KECK and Planck 353 GHz polarization cross-correlation data gives an even stronger bound $r<0.1$. We comment on possible effects of a large positive tilt on the background expansion and show that depending on the assumptions regarding the UV cutoff ($k_{\mathrm{UV}}/k_{*}=10^{24}$) of the primordial spectrum of gravitational waves, the strongest bounds on $n_t=0.07_{-0.80}^{+0.52}$ are derived from this effect.

We evaluate energy levels of the $K\pi$ system in the $K^{*}$ channel in finite volume using chiral unitary theory. We use these energy levels to obtain $K\pi$ phase shifts and then obtain the $K^{*}$ mass and its decay width. We investigate their dependence on the pion mass and compare this with lattice QCD calculations. We also compare our method with the standard Lüscher approach and solve the inverse problem to obtain the $K\pi$ phase shifts from these “synthetic” lattice data.

We investigate the low-lying eigenmodes of the Dirac matrix with the aim to gain more insight into the temperature dependence of the anomalous $U_A(1)$ symmetry in QCD. We use the overlap operator to probe dynamical QCD configurations generated with ($2+1$)-flavors of highly improved staggered quarks. We find no evidence of a gap opening up in the infrared region of the eigenvalue spectrum even at $1.5T_c$, $T_c$ being the chiral crossover temperature. Instead, we observe an accumulation of near-zero eigenmodes. We argue that these near-zero eigenmodes are primarily responsible for the anomalous breaking of the axial symmetry still being effective. At $1.5T_c$, these near-zero eigenmodes remain localized and their distribution is consistent with the dilute instanton gas picture. At this temperature, the average size of the instantons is $0.223(8)\mathrm{fm}$ and their density is $0.147(7){\mathrm{fm}}^{-4}$.

The quark flavor distribution functions of the octet baryons ($N$, $\mathrm{\Sigma }$, $\mathrm{\Xi }$, and $\mathrm{\Lambda }$) have been calculated in the chiral constituent quark model. In particular, the valence and sea quark flavor distribution functions of the scalar density matrix elements of octet baryons have been computed explicitly. The implications of chiral symmetry breaking and SU(3) symmetry breaking have been discussed in detail for the sea quark asymmetries, a fraction of a particular quark (antiquark) present in a baryon, flavor structure functions and the Gottfried integral. The meson-baryon sigma terms ${\sigma }_{\pi B}$, ${\sigma }_{KB}$, and ${\sigma }_{\eta B}$ for the case of $N$, $\mathrm{\Sigma }$, and $\mathrm{\Xi }$ baryons have also been calculated. The results have been compared with the recent available experimental observations for the case of $N$, and how the future experiments for $\mathrm{\Sigma }$, $\mathrm{\Xi }$, and $\mathrm{\Lambda }$ can provide important constraints to describe the role of nonvalence (sea) degrees of freedom has been discussed.

Particle production caused by the oscillation after inflation is important since it explains reheating after inflation. On the particle theory side, we know that effective action may have additional higher dimensional terms (usually called nonrenormalizable terms) suppressed by the cutoff scale. Moreover, interaction between the inflaton and so-called moduli field will be higher dimensional. Therefore, if such higher dimensional interaction is significant for resonant particle production, one cannot avoid the effect in a preheating study. We explicitly calculated the required number of oscillations for the energy transfer. Consequently, cosmological history of an oscillating field and the moduli problem can be reconsidered.

The clustering ratio $\eta$, a large-scale structure observable originally designed to constrain the shape of the power spectrum of matter density fluctuations, is shown to provide a sensitive probe of the nature of gravity in the cosmological regime. We apply this analysis to $F(R)$ theories of gravity using the luminous red galaxy sample extracted from the spectroscopic Sloan Digital Sky Survey (SDSS) data release 7 and 10 catalogs. We find that general relativity (GR), complemented with a Friedmann-Robertson-Walker (FRW) cosmological model with parameters fixed by the Planck satellite, describes extremely well the clustering of galaxies up to $z\sim 0.6$. On large cosmic scales, the absolute amplitude of deviations from GR, $|f_{R_0}|$, is constrained to be smaller than $4.6\times 10^{-5}$ at the 95% confidence level. This bound makes cosmological probes of gravity almost competitive with the sensitivity of Solar System tests, although still one 1 order of magnitude less effective than astrophysical tests. We also extrapolate our results to future large surveys like Euclid and show that the astrophysical bound will certainly remain out of reach for such a class of modified-gravity models that only differ from $\mathrm{\Lambda }\mathrm{CDM}$ at low redshifts.

We derive simple analytic expressions for the (coherent and semicoherent) phase metrics of continuous-wave sources in low-eccentricity binary systems for the two regimes of long and short segments compared to the orbital period. The resulting expressions correct and extend previous results found in the literature. We present results of extensive Monte Carlo studies comparing metric mismatch predictions against the measured loss of detection statistics for binary parameter offsets. The agreement is generally found to be within $\sim 10\%–30\%$. For an application of the metric template expressions, we estimate the optimal achievable sensitivity of an Einstein@Home directed search for Scorpius X-1, under the assumption of sufficiently small spin wandering. We find that such a search, using data from the upcoming advanced detectors, would be able to beat the torque-balance level [R. V. Wagoner, Astrophys. J. 278, 345 (1984); L. Bildsten, Astrophys. J. 501, L89 (1998).] up to a frequency of $\sim 500–600\mathrm{Hz}$, if orbital eccentricity is well constrained, and up to a frequency of $\sim 160–200\mathrm{Hz}$ for more conservative assumptions about the uncertainty on orbital eccentricity.