During the motion of a binary pulsar around the Galactic center, the pulsar and its companion experience a wind of dark-matter particles that can affect the orbital motion through dynamical friction. We show that this effect produces a characteristic seasonal modulation of the orbit and causes a secular change of the orbital period whose magnitude can be well within the astonishing precision of various binary-pulsar observations. Our analysis is valid for binary systems with orbital period longer than a day. By comparing this effect with pulsar-timing measurements, it is possible to derive model-independent upper bounds on the dark-matter density at different distances $D$ from the Galactic center. For example, the precision timing of $\mathrm{J}1713+0747$ imposes ${\rho }_{\mathrm{DM}}\lesssim {10}^5{\mathrm{GeV}/\mathrm{cm}}^3$ at $D\approx 7\mathrm{kpc}$. The detection of a binary pulsar at $D\lesssim 10\mathrm{pc}$ could provide stringent constraints on dark-matter halo profiles and on growth models of the central black hole. The Square Kilometer Array can improve current bounds by 2 orders of magnitude, potentially constraining the local density of dark matter to unprecedented levels.

The dynamics of the tilted axisymmetric Bianchi IX cosmological models are explored allowing energy flux in the source fluid. The Einstein equations and the continuity equation are presented treating the equation of state $w$ and the tilt angle of the fluid $\lambda$ as time-dependent functions, but when analyzing the phase space $w$ and $\lambda$ are considered free parameters and the shear, the vorticity and the curvature of the spacetime span a three-dimensional phase space that contains seven fixed points. One of them is an attractor that inflates the universe anisotropically, thus providing a counterexample to the cosmic no-hair conjecture. Also, examples of realistic though fine-tuned cosmologies are presented wherein the rotation can become significant towards the present epoch but the shear stays within the observational bounds. The examples suggest that the model used here can explain the parity-violating anomalies of the cosmic microwave background. The result significantly differs from an earlier study, where a nonaxisymmetric Bianchi IX type model with a tilted perfect dust source was found to induce too much shear for observationally significant vorticity.

We investigate the possible implications of the measured value of the scalar tilt $n_s$ for the tensor-to-scalar ratio $r$ in slow-roll, single-field inflationary models. The measured value of the tilt satisfies $n_s-1\sim 1/N_{*}$, where $N_{*}\sim 60$ is the number of $e$-folds for observationally relevant scales. If this is not a coincidence and the scaling holds for different values of $N$, it strongly suggests that either $r$ is as big as $10^{-1}$ (a possibility in tension with the recent data), or smaller than $10^{-2}$ and exponentially dependent on $n_s$. A large region of the $(n_s,r)$ plane is not compatible with this scaling.

We extend the gravitational self-force methodology to identify and compute new $\mathcal{O}(\mu )$ tidal invariants for a compact body of mass $\mu$ on a quasicircular orbit about a black hole of mass $M\gg \mu$. In the octupolar sector we find seven new degrees of freedom, made up of $3+3$ conservative/dissipative ‘electric’ invariants and $3+1$ ‘magnetic’ invariants, satisfying $1+1$ and $1+0$ trace conditions. We express the new invariants for equatorial circular orbits on Kerr spacetime in terms of the regularized metric perturbation and its derivatives; and we evaluate the expressions in the Schwarzschild case. We employ both Lorenz gauge and Regge-Wheeler gauge numerical codes, and the functional series method of Mano, Suzuki and Takasugi. We present (i) highly-accurate numerical data and (ii) high-order analytical post-Newtonian expansions. We demonstrate consistency between numerical and analytical results, and prior work. We explore the application of these invariants in effective one-body models and binary black hole initial-data formulations.

We study the effective field theory (EFT) of large-scale structure for cosmic density and momentum fields. We show that the finite part of the two-loop calculation and its counterterms introduces an apparent scale dependence for the leading-order parameter $c_{\mathrm{s}}^2$ of the EFT starting at $k=0.1h{\mathrm{Mpc}}^{-1}$. These terms limit the range over which one can trust the one-loop EFT calculation at the 1% level to $k<0.1h{\mathrm{Mpc}}^{-1}$ at redshift $z=0$. We construct a well-motivated one-parameter ansatz to fix the relative size of the one- and two-loop counterterms using their high-$k$ sensitivity. Although this one-parameter model is a very restrictive choice for the counterterms, it explains the apparent scale dependence of $c_{\mathrm{s}}^2$ seen in simulations. It is also able to capture the scale dependence of the density power spectrum up to $k\approx 0.3h{\mathrm{Mpc}}^{-1}$ at the 1% level at redshift $z=0$. Considering a simple scheme for the resummation of large-scale motions, we find that the two-loop calculation reduces the need for this IR resummation at $k<0.2h{\mathrm{Mpc}}^{-1}$. Finally, we extend our calculation to momentum statistics and show that the same one-parameter model can also describe density-momentum and momentum-momentum statistics.

We propose a novel method to probe primordial gravitational waves by means of primordial black holes (PBHs). When the amplitude of primordial tensor perturbations on comoving scales much smaller than those relevant to cosmic microwave background is very large, it induces scalar perturbations due to second-order effects substantially. If the amplitude of resultant scalar perturbations becomes too large, then PBHs are overproduced to a level that is inconsistent with a variety of existing observations constraining their abundance. This leads to upper bounds on the amplitude of initial tensor perturbations on superhorizon scales. The resultant PBH upper bounds turn out be tighter than other bounds obtained from big bang nucleosynthesis and cosmic microwave background.

The latest Planck results show a power deficit in the temperature anisotropies near $\ell \approx 20$ in the cosmic microwave background (CMB). This observation can hardly be explained within the standard inflationary $\mathrm{\Lambda }$-cold-dark-matter ($\mathrm{\Lambda }\mathrm{CDM}$) scenario. In this paper we consider a string theory inspired inflationary model (axion monodromy inflation) with a step-like modulation in the potential which gives rise to observable signatures in the primordial perturbations. One interesting phenomenon is that the primordial scalar modes experience a sudden suppression at a critical scale when the modulation occurs. By fitting to the CMB data, we find that the model can nicely explain the $\ell \approx 20$ power deficit anomaly as well as predict specific patterns in the temperature-polarization correlation and polarization autocorrelation spectra. Though the significance of the result is not sufficient to claim a detection, our analysis reveals that fundamental physics at extremely high energy scales, namely, some effects inspired by string theory, may be observationally testable in forthcoming cosmological experiments.

A recently developed variant of the so-called optimized perturbation theory (OPT), making it perturbatively consistent with renormalization group (RG) properties, RGOPT, was shown to drastically improve its convergence for zero temperature theories. Here the RGOPT adapted to finite temperature is illustrated with a detailed evaluation of the two-loop pressure for the thermal scalar $\lambda {\varphi }^4$ field theory. We show that already at the simple one-loop level this quantity is exactly scale-invariant by construction and turns out to qualitatively reproduce, with a rather simple procedure, results from more sophisticated resummation methods at two-loop order, such as the two-particle irreducible approach typically. This lowest order also reproduces the exact large-$N$ results of the $O(N)$ model. Although very close in spirit, our RGOPT method and corresponding results differ drastically from similar variational approaches, such as the screened perturbation theory or its QCD-version, the (resummed) hard thermal loop perturbation theory. The latter approaches exhibit a sensibly degrading scale dependence at higher orders, which we identify as a consequence of missing RG invariance. In contrast RGOPT gives a considerably reduced scale dependence at two-loop level, even for relatively large coupling values $\sqrt{\lambda /24}\sim \mathcal{O}(1)$, making results much more stable as compared with standard perturbation theory, with expected similar properties for thermal QCD.

Diboson resonance with mass of 1.8–2 TeV is reported successively by CMS and ATLAS experiments in proton-proton collisions at $\sqrt{s}=8\mathrm{TeV}$. We investigate the potentiality of Higgs singlet as the TeV resonance. The challenges of low production cross section and high width for a fundamental scalar could be got over by three factors: (1) larger Yukawa couplings, (2) larger number of heavy quarks and (3) smaller mixing angle with standard model Higgs. We find that the required factors could be realized in the framework of two vectorlike triplet quarks (VLTQs) and the resulting production cross section and decay fraction of heavy Higgs $\sigma (pp\to H)\times \mathrm{BR}(H\to W^{+}{W}^{-}+ZZ)$ can be of $\mathcal{O}(10)\mathrm{fb}$ when masses of new heavy quarks are 1 TeV, the values of Yukawa couplings are around 3 and the mixing angle is $\sin \theta \sim 0.11$. We also find that the SM Higgs production and its decay in the process $pp\to h\to \gamma \gamma$ could be still consistent with current data when a color-triplet scalar $(3,3{)}_{1/3}$ is considered. Furthermore, we study the product of VLTQ-pair production cross section and the BRs of VLTQ decays, and find that the cross sections in the decay channels, such as $u_{4,5}\to b{W}^{+}$, $d_5\to t{W}^{-}$ and $d_4\to bh(Z)$ could be 7–17 fb at 13 TeV LHC.

In order to reproduce the measured mass of the Higgs boson $m_h=125\mathrm{GeV}$ in the minimal supersymmetric standard model, one usually has to rely on heavy stops. By introducing a new gauge sector, the Higgs mass gets a tree-level contribution via a nondecoupling $D$-term, and $m_h=125\mathrm{GeV}$ can be obtained with lighter stops. In this paper, we study the values of the stops masses needed to achieve the correct Higgs mass in a setup where the gauge group is extended by a single $U(1{)}_x$ interaction. We derive the experimental limits on the mass of the $Z^{\prime }$ gauge boson in this setup, then discuss how the stops masses vary as a function of the free parameters introduced by the new sector. We find that the correct Higgs mass can be reproduced with stops in a region between 700–800 GeV and a $Z^{\prime }$ resonance close to the 2.5 TeV bound from the run I of the LHC, or in a higher region 800–900 GeV if the $Z^{\prime }$ resonance is heavier (3.1 TeV). This region of parameter space will be quickly accessible at run II of the LHC, and we discuss the impact of the projected run-II bounds on the $U(1{)}_x$ parameter space. We also discuss the phenomenology of the Higgs-like particles introduced to break $U(1{)}_x$ and conclude their effects are too small to be detected at current colliders.

We compute the branching ratio and forward-backward asymmetry ($A_{\mathrm{FB}}$) distribution for the rare dileptonic decay $B\to K^{*}{\mu }^{+}{\mu }^{-}$ for the full range of $q^2$, the dimuon mass squared, region. For the required form factors, we use nonperturbative inputs as predicted by the anti-de Sitter (AdS)/QCD correspondence. When using the Breit-Wigner model with momentum-dependent decay constants to account for the $\psi$ and ${\psi }^{\prime }$ resonance effects in the nonresonance region of the spectrum, we find our predictions to be in better agreement with the experimental data for the branching ratio.

The entanglement interactions between the Polyakov loop and chiral condensate have been recently studied in the entangled Polyakov-loop Nambu–Jona-Lasinio model (EPNJL). The calculation shows that such an interaction plays an important role in the pseudocritical temperatures of deconfinement and chiral symmetry restoration. As a further study, here we construct a hadron-quark two-equation-of-state (two-EoS) model, based on the Walecka-quantum hadrodynamics and the EPNJL pictures, in order to study the equilibrium transition between hadronic and quark matter in heavy-ion collisions at finite densities and temperatures. We can explore the phase diagram of strongly interacting matter and the transition boundaries from nuclear to quark matter. We discuss the influence of the entanglement interaction on the critical point of the expected first-order phase transition in the two-EoS model. In particular, for charge asymmetric matter, we analyze the local asymmetry of the $u$, $d$ quarks as a function of quark concentration in the hadron-quark mixed phase during the phase transition. We finally propose some related observables that are possibly measurable in heavy-ion collision experiments.

We study the off-shell mixing and renormalization of flavor-diagonal dimension-five $T$- and $P$-odd operators involving quarks, gluons, and photons, including quark electric dipole and chromoelectric dipole operators. We present the renormalization matrix to one loop in the $\overline{\mathrm{MS}}$ scheme. We also provide a definition of the quark chromoelectric dipole operator in a regularization-independent momentum-subtraction scheme suitable for nonperturbative lattice calculations and present the matching coefficients with the $\overline{\mathrm{MS}}$ scheme to one loop in perturbation theory, using both the naïve dimensional regularization and ’t Hooft–Veltman prescriptions for ${\gamma }_5$.

The same leptoquarks that explain the recently observed anomaly in $R_K$ can generate naturally small Majorana neutrino masses at one-loop level through mixing with the standard model Higgs. This is particularly relevant in models with at least two leptoquarks contributing to $b\to sll$ transitions.

Understanding the charged current quasielestic (CCQE) neutrino-nucleus interaction is important for precision studies of neutrino oscillations. The theoretical description of the interaction depends on the combination of a nuclear model with the knowledge of form factors. While the former has received considerable attention, the latter, in particular, the axial form factor, is implemented using the historical dipole model. Instead, we use a model-independent approach, presented in a previous study, to analyze the muon-antineutrino CCQE mineral oil data published by the MiniBooNE collaboration. We combine the cross section for scattering of antineutrinos off protons in carbon and hydrogen, using the same axial form factor for both. The extracted value of the axial mass parameter $m_A=0.84_{-0.04}^{+0.12}\pm 0.11\mathrm{GeV}$ is in very good agreement with the model-independent value extracted from MiniBooNE’s neutrino data. Going beyond a one-parameter description of the axial form factor, we extract values of the axial form factor in the range of $Q^2=0.1\dots 1.0{\mathrm{GeV}}^2$, finding a very good agreement with the analogous extraction from the neutrino data. We discuss the implications of these results.

A seesaw mechanism is presented in the neutrino sector and a new phase of $CP$ violation ($\alpha$) emerges in the interplay between the type-I and type-III seesaw schemes. This phase is inside the mixing term, and thus it cannot be rotated away in the Yukawa Lagrangian and, therefore, the heavy symmetry states cannot be in a diagonal weak basis in the broken phase. Some particular descriptions are analyzed suggesting that if the usual Yukawa couplings are suppressed, leptogenesis still occurs due to a new interacting vertex with fermion triplet $T$, fermion singlets $N$, and scalar triple, $\mathrm{\Sigma }$, which now is included to mediate the interactions. The evaluated $CP$ violation is enough to generate the observed matter-antimatter asymmetry even in the minimal $1N+1T$ case (independently of $\alpha$) or in the $2N+1T$ approach (controlled by $\alpha$). The latter introduces more $CP$ contributions to leptogenesis due to new diagrams which are now possible even with the suppressed imaginary part of the standard Yukawa couplings and can induce the observed baryon-to-photon ratio.

We show that active neutrino masses and a keV-GeV mass sterile neutrino dark matter candidate can result from a modified, low energy seesaw mechanism if right-handed neutrinos are charged under a new symmetry broken by a scalar field vacuum expectation value at the PeV scale. The dark matter relic abundance can be obtained through active-sterile oscillation, freeze-in through the decay of the heavy scalar, or freeze-in via nonrenormalizable interactions at high temperatures. The low energy effective theory maps onto the widely studied $\nu \mathrm{MSM}$ framework.

We examine the physics of the early universe when Majorana neutrinos (${\nu }_e$, ${\nu }_{\mu }$, ${\nu }_{\tau }$) possess transition magnetic moments. These extra couplings beyond the usual weak interaction couplings alter the way neutrinos decouple from the plasma of electrons/positrons and photons. We calculate how transition magnetic moment couplings modify neutrino decoupling temperatures, and then use a full weak, strong, and electromagnetic reaction network to compute corresponding changes in big bang nucleosynthesis abundance yields. We find that light element abundances and other cosmological parameters are sensitive to magnetic couplings on the order of $10^{-10}{\mu }_B$. Given the recent analysis of sub-MeV Borexino data which constrains Majorana moments to the order of $10^{-11}{\mu }_B$ or less, we find that changes in cosmological parameters from magnetic contributions to neutrino decoupling temperatures are below the level of upcoming precision observations.

We derived local boundary counterterms in massive gravity theory with a negative cosmological constant in four dimensions. With these counterterms at hand, we analyzed the properties of the boundary field theory in the context of AdS/CFT duality by calculating the boundary stress-energy tensor. The calculation shows that the boundary stress-energy tensor is conserved, and momentum dissipation might occur on the level of linear response only. We also calculated the thermodynamic quantities and the boundary stress-energy tensor for a specific type of solutions. The thermodynamic potentials agree with the results of literature up to some constants which can be removed by adding finite counterterms.