The symmetron model is a scalar-tensor theory of gravity with a screening mechanism that suppresses the effect of the symmetron field at high densities characteristic of the Solar System and laboratory scales but allows it to act with gravitational strength at low density on the cosmological scale. We elucidate the screening mechanism by showing that in the quasistatic Newtonian limit there are precise analogies between symmetron gravity and electrostatics for both strong and weak screening. For strong screening we find that large dense bodies behave in a manner analogous to perfect conductors in electrostatics. Based on this analogy we find that the symmetron field exhibits a lightning rod effect wherein the field gradients are enhanced near the ends of pointed or elongated objects. An ellipsoid placed in a uniform symmetron gradient is shown to experience a torque. By symmetry there is no gravitational torque in this case. Hence this effect unmasks the symmetron and might serve as the basis for future laboratory experiments. The symmetron force between a point mass and a large dense body includes a component corresponding to the interaction of the point mass with its image in the larger body. None of these effects have counterparts in the Newtonian limit of Einstein gravity. We discuss the similarities between symmetron gravity and the chameleon model as well as the differences between the two.

We show that the $R^{(3)}\delta K$ operator in effective field theory is significant for avoiding the instability of nonsingular bounce, where $R^{(3)}$ and $K_{\mu \nu }$ are the three-dimensional Ricci scalar and the extrinsic curvature on the spacelike hypersurface, respectively. We point out that the covariant Lagrangian of $R^{(3)}\delta K$, i.e., $L_{R^{(3)}\delta K}$, has the second order derivative couplings of scalar field to gravity which do not appear in Horndeski theory or its extensions but does not bring the Ostrogradski ghost. We also discuss the possible effect of $L_{R^{(3)}\delta K}$ on the primordial scalar perturbation in the inflation scenario.

A Hamiltonian approach to the equations of general relativity is proposed using the powerful mathematical language of multivector-valued differential forms. In the approach, the gravitational coordinates are the 12 spatial components of the line interval (the vierbein) including their antisymmetric parts, and their 12 conjugate momenta. A feature of the proposed formalism is that it allows Lorentz gauge freedoms to be imposed on the Lorentz connections rather than on the vierbein, which may facilitate numerical integration in some challenging problems. The 40 Hamilton’s equations comprise $12+12=24$ equations of motion, ten constraint equations (first class constraints, which must be arranged on the initial hypersurface of constant time, but which are guaranteed thereafter by conservation laws), and six identities (second class constraints). The six identities define a trace-free spatial tensor that is the gravitational analog of the magnetic field of electromagnetism. If the gravitational magnetic field is promoted to an independent field satisfying its own equation of motion, then the system becomes the Wahlquist-Estabrook-Buchman-Bardeen (WEBB) system, which is known to be strongly hyperbolic. Some other approaches, including Arnowitt-Deser-Misner, Baumgarte-Shapiro-Shibata-Nakamura, WEBB, and loop quantum gravity, are translated into the language of multivector-valued forms, bringing out their underlying mathematical structure.

We investigate the flux tube joining two equal and opposite electric charges using the dual Ginzburg-Landau model of superconductivity. The model is supplemented with an additional scalar field carrying a non-Abelian global symmetry, broken in the vortex cores. The presence of orientational moduli makes the flux tube non-Abelian. We perform a detailed study of the low-energy theory of this soliton. We also analyze the solution representing superconducting droplets in the presence of the monopole-antimonopole pair.

The strong and radiative decays of the low-lying $S$- and $P$-wave ${\mathrm{\Lambda }}_{c(b)}$, ${\mathrm{\Sigma }}_{c(b)}$, ${\mathrm{\Xi }}_{c(b)}$, ${{\mathrm{\Xi }}_{c(b)}}^{\prime }$, and ${\mathrm{\Omega }}_{c(b)}$ baryons are systematically studied in a constituent quark model. We find that the radiative decay mode ${\mathrm{\Lambda }}_b^0\gamma$ could be very useful for us to establish the missing neutral states ${\mathrm{\Sigma }}_b^0$ and ${\mathrm{\Sigma }}_b^{*0}$. Our calculation shows that most of those missing $\lambda$-mode $P$-wave singly heavy baryons have a relatively narrow decay width of less than 30 MeV. Their dominant strong and radiative decay channels can be ideal for searching for their signals in future experiments. The ${\mathrm{\Sigma }}_c(2800)$ resonance may be assigned to $|{\mathrm{\Sigma }}_c{{}^{2}P}_{\lambda }{\frac{3}{2}}^{-}⟩$ with $J^P=3/2^{-}$ or $|{\mathrm{\Sigma }}_c{{}^{4}P}_{\lambda }{\frac{5}{2}}^{-}⟩$ with $J^P=5/2^{-}$. In general, the excitations of $|{{}^{2}P}_{\lambda }{\frac{3}{2}}^{-}⟩$ and $|{{}^{4}P}_{\lambda }{\frac{5}{2}}^{-}⟩$ of the ${\mathbf{6}}_F$ multiplet have similar strong decay properties. In order to identify them, angular distributions of their decays in either strong decay modes or radiative transitions should be needed.

New physics at the TeV scale can affect the dynamics of the electroweak phase transition in many ways. In this paper, we evaluate its impact on the rate of baryon-number violation via sphaleron transitions. We parametrize the effect of new physics with dimension-six operators, and we use the Newton-Kantorovich method to numerically solve the resulting equations of motion. Depending on the sign of the coefficient of the dimension-six operators, their presence can either increase or decrease the sphaleron energy at the level of a few percent, parametrically of order $m_W^2/{\mathrm{\Lambda }}^2$ where $\mathrm{\Lambda }$ is the scale suppressing the dimension-six operator. The baryon-number washout condition, typically written as $v_c/T_c>1$, is directly proportional to the sphaleron energy, and we discuss how the presence of dimension-six operators can affect electroweak baryogenesis.

The lowest dimension three-gluon currents that couple to the exotic $0^{\pm -}$ glueballs have been constructed using the helicity formalism. Based on the constructed currents, we obtain new QCD sum rules that have been used to extract the masses and the decay constants of the scalar exotic $0^{\pm -}$ glueballs. We estimate the masses for the scalar state and for the pseudoscalar state to be $m_{+}={9.8}_{-1.4}^{+1.3}\mathrm{GeV}$ and $m_{-}={6.8}_{-1.2}^{+1.1}\mathrm{GeV}$.

We have presented the results for the single and double spin asymmetries in semi-inclusive deep inelastic scatterings for proton in a light front quark-diquark model. The asymmetries generated by the T-even TMDs are discussed here. The model predictions are found to agree with the available data. We also present our model predictions for the Collins asymmetry for the future electron-ion collider experiments.

We calculate the probabilities of various charmed meson molecules for $X(4260)$ under the framework of the ${{}^{3}P}_0$ model. The results indicate that, even though heavy quark spin symmetry forbids $S$ wave coupling of $D_1\overline{D}$ to the ${{}^{3}S}_1$ charmonia [$\psi (nS)$], the $D$ wave coupling is allowed and not negligible. Under this symmetry, the $D_1\overline{D}$ can couple to ${{}^{3}D}_1$ charmonia [$\psi (nD)$] via both $S$ and $D$ waves, and the overall coupling is around three times larger than that of $\psi (nS)$. The $X(4260)$ cannot be a pure molecule but a mixture of a charmonium and various charmed meson components. Since the $D_1\overline{D}$ couples strongly to $\psi (nD)$, our results suggest that, in the $D_1\overline{D}$ molecular picture, the charmonium core of $X(4260)$ is $\psi (nD)$ instead of $\psi (nS)$. As a result, the experimental fact that the $R$ ratio has a dip around 4.26 GeV can be understood in the $D_1\overline{D}$ molecular picture of the $X(4260)$.

We use the recently developed generalized double-copy procedure to construct an integrand for the five-loop four-point amplitude of $\mathcal{N}=8$ supergravity. This construction starts from a naive double copy of the previously computed corresponding amplitude of $\mathcal{N}=4$ super-Yang-Mills theory. This is then systematically modified by adding contact terms generated in the context of the method of maximal unitarity cuts. For the simpler generalized cuts, whose corresponding contact terms tend to be the most complicated, we derive a set of formulas relating the contact contributions to the violations of the dual Jacobi identities in the relevant gauge-theory amplitudes. For more complex generalized unitarity cuts, which tend to have simpler contact terms associated with them, we use the method of maximal cuts more directly. The five-loop four-point integrand is a crucial ingredient towards future studies of ultraviolet properties of $\mathcal{N}=8$ supergravity at five loops and beyond. We also present a nontrivial check of the consistency of the integrand, based on modern approaches for integrating over the loop momenta in the ultraviolet region.

A quantum representation of holonomies and exponentiated fluxes of a U(1) gauge theory that contains the Pullin-Dittrich-Geiller (DG) vacuum is presented and discussed. Our quantization is performed manifestly in a continuum theory, without any discretization. The discreteness emerges on the quantum level as a property of the spectrum of the quantum holonomy operators. The new type of a cylindrical consistency present in the DG approach now follows easily and naturally. A generalization to the non-Abelian case seems possible.

We consider the first order form of the Einstein-Hilbert action and quantize it using the path integral. Two gauge fixing conditions are imposed so that the graviton propagator is both traceless and transverse. It is shown that these two gauge conditions result in two complex fermionic vector ghost fields and one real bosonic vector ghost field. All Feynman diagrams to any order in perturbation theory can be constructed from two real bosonic fields, two fermionic ghost fields and one real bosonic ghost field that propagate. These five fields interact through just five three point vertices and one four point vertex.

We present a systematic and robust approach to nonlinear gravitational perturbations of vacuum spacetimes. This approach provides a basis for a theory of nonlinear gravitational waves. In particular, we show that the system of perturbative Einstein equations reduces at each perturbation order to two (for each gravitational mode in $3+1$ dimensions on which our study is focused) scalar wave equations, and then we show how the metric perturbations can be explicitly obtained, once the solutions to these scalar wave equations are known. These results show that the concept of polarization of a gravitational wave does make sense also beyond the linear approximation.

We analyze scale invariant quadratic quantum gravity incorporating nonminimal coupling to a multiplet of scalar fields in a gauge theory, with particular emphasis on the consequences for its interpretation resulting from a transformation from the Jordan frame to the Einstein frame. The result is the natural emergence of a de Sitter space solution which, depending the gauge theory and region of parameter space chosen, can be free of ghosts and tachyons, and completely asymptotically free. In the case of an SO(10) model, we present a detailed account of the spontaneous symmetry breaking, and we calculate the leading (two-loop) contribution to the dilaton mass.

We study the effect of nonquadrupolar modes in the detection and parameter estimation of gravitational waves (GWs) from black hole binaries with nonprecessing spins, using Advanced LIGO. We evaluate the loss of the signal-to-noise ratio (SNR) and the systematic errors in the estimated parameters when a quadrupole-mode template family is used to detect GW signals with all the relevant modes. Target signals including nonquadrupole modes are constructed by matching numerical-relativity simulations of nonprecessing black hole binaries describing the late inspiral, merger, and ringdown with post-Newtonian/effective-one-body waveforms describing the early inspiral. We find that neglecting nonquadrupole modes will, in general, cause unacceptable loss in the detection rate and unacceptably large systematic errors in the estimated parameters, for the case of massive binaries with large mass ratios. For a given mass ratio, neglecting subdominant modes will result in a larger loss in the detection rate for binaries with aligned spins. For binaries with antialigned spins, quadrupole-mode templates are more effectual in detection, at the cost of introducing a larger systematic bias in the parameter estimation. We provide a summary of the regions in the parameter space where neglecting nonquadrupole modes will cause an unacceptable loss of detection rates and unacceptably large systematic biases in the estimated parameters.

We present two different versions of the consistent theory of massive gravitons in arbitrary spacetimes which are simple enough for practical applications. The theory is described by a nonsymmetric rank-2 tensor whose equations of motion imply six algebraic and five differential constraints, reducing the number of independent components to five. The theory reproduces the standard description of massive gravitons in Einstein spaces. In generic spacetimes it does not show the massless limit and always propagates five degrees of freedom, even for the vanishing mass parameter. We illustrate these features by an explicit calculation for a homogeneous and isotropic cosmological background. We find that the gravitons are stable if they are sufficiently massive, hence they may be a part of dark matter at present. We also discuss other possible applications.

We present a formalism to compute Lagrangian displacement fields for a wide range of cosmologies in the context of perturbation theory up to third order. We emphasize the case of theories with scale-dependent gravitational strengths, such as chameleons, but our formalism can be accommodated to other modified gravity theories. In the nonlinear regime, two qualitative features arise. One, as is well known, is that nonlinearities lead to a screening of the force mediated by the scalar field. The second is a consequence of the transformation of the Klein-Gordon equation from Eulerian to Lagrangian coordinates, producing frame lagging terms that are important especially at large scales, and if not considered, the theory does not reduce to the $\mathrm{\Lambda }\mathrm{CDM}$ model in that limit. We apply our formalism to compute the one-loop power spectrum and the correlation function in $f(R)$ gravity by using different resummation schemes. We further discuss the IR divergences of these formalisms.

The presence of ubiquitous magnetic fields in the universe is suggested from observations of radiation and cosmic ray from galaxies or the intergalactic medium (IGM). One possible origin of cosmic magnetic fields is the magnetogenesis in the primordial universe. Such magnetic fields are called primordial magnetic fields (PMFs), and are considered to affect the evolution of matter density fluctuations and the thermal history of the IGM gas. Hence the information of PMFs is expected to be imprinted on the anisotropies of the cosmic microwave background (CMB) through the thermal Sunyaev-Zel’dovich (tSZ) effect in the IGM. In this study, given an initial power spectrum of PMFs as $P(k)\propto B_{1\mathrm{Mpc}}^2{k}^{n_B}$, we calculate dynamical and thermal evolutions of the IGM under the influence of PMFs, and compute the resultant angular power spectrum of the Compton $y$-parameter on the sky. As a result, we find that two physical processes driven by PMFs dominantly determine the power spectrum of the Compton $y$-parameter; (i) the heating due to the ambipolar diffusion effectively works to increase the temperature and the ionization fraction, and (ii) the Lorentz force drastically enhances the density contrast on small scale just after the recombination epoch. These facts result in making the anisotropies of the CMB temperature on small scales, and we find that the signal goes up to $10\mu {\mathrm{K}}^2$ around $\ell \sim {10}^6$ with $B_{1\mathrm{Mpc}}=0.1\mathrm{nG}$ and $n_B=0.0$. Therefore, CMB measurements on such small scales may provide a hint for the existence of the PMFs.

The AMS-02 collaboration has published the measurement of the cosmic antiproton to proton ratio $\overline{p}/p$ and the $\overline{p}$ flux with a high precision up to $\sim 450\mathrm{GeV}$. In this work, we perform a systematic analysis of the secondary antiproton flux generated by the cosmic ray interaction with the interstellar gas. The uncertainties of the prediction from the cosmic ray propagation process and the hadronic interaction models are analyzed. We find the two effects may interplay with each other in the prediction. In some combinations of the propagation and hadronic interaction models the secondary $\overline{p}$ predictions give quite good fit to the AMS-02 data and thus set very stringent constraint on the dark matter annihilation cross section, while in some cases the predictions would deviate from the data. Especially, we find that the epos lhc hadronic model, which can fit the collider data very well, predicts a slightly lower $\overline{p}/p$ ratio than the AMS-02 data at the high energy end.