Besides scalarized black holes and wormholes, Einstein-scalar-Gauss-Bonnet theories allow also for particlelike solutions. The scalar field of these particlelike solutions diverges at the origin, akin to the divergence of the Coulomb potential at the location of a charged particle. However, these particlelike solutions possess a globally regular metric, and their effective stress-energy tensor is free from pathologies, as well. We determine the domain of existence for particlelike solutions in a number of Einstein-scalar-Gauss-Bonnet theories, considering dilatonic and power-law coupling functions, and we analyze the physical properties of the solutions. Interestingly, the solutions may possess pairs of lightrings, and thus represent ultracompact objects. We determine the location of these lightrings, and study the effective potential for the occurrence of echoes in the gravitational-wave spectrum. We also address the relation of these particlelike solutions to the respective wormhole and black-hole solutions, and clarify the limiting procedure to recover the Fisher solution (also known as the Janis-Newman-Winicour-Wyman solution).

In Einstein’s general relativity, gravity is mediated by a massless metric field. The extension of general relativity to consistently include a mass for the graviton has profound implications for gravitation and cosmology. Salient features of various massive gravity theories can be captured by Galileon models, the simplest of which is the cubic Galileon. The presence of the Galileon field leads to additional gravitational radiation in binary pulsars where the Vainshtein mechanism is less suppressed than its fifth-force counterpart, which deserves a detailed confrontation with observations. We prudently choose 14 well-timed binary pulsars, and from their intrinsic orbital decay rates we put a new bound on the graviton mass, $m_g\lesssim 2\times {10}^{-28}\mathrm{eV}/c^2$ at the 95% confidence level, assuming a flat prior on $\ln m_g$. It is equivalent to a bound on the graviton Compton wavelength ${\lambda }_g\gtrsim 7\times {10}^{21}\mathrm{m}$. Furthermore, we extensively simulate times of arrival for pulsars in orbit around stellar-mass black holes and the supermassive black hole at the Galactic Center, and we investigate their prospects of probing the cubic Galileon theory in the near future.

The framework of “time-dependent basis light-front quantization” (tBLFQ) offers a nonperturbative approach to scattering problems in external fields, based on Fock space truncation. Here we extend tBLFQ to include spatio-temporal field inhomogeneities in multiple spacetime directions. This extension is necessary for the proper modeling of e.g. intense laser fields. We focus on the example of nonlinear Compton scattering of an electron on an axicon-type laser, with an emphasis on the transverse structure of the beam. We analyze the impact of field intensity and particle energy, as well as basis truncation effects, on the radiation spectrum of the scattered electron.

We propose the simplest TeV-scale scotogenic extension of the original 3-3-1 theory, where dark matter stability is linked to the Dirac nature of neutrinos, which results from an unbroken $B-L$ gauge symmetry. The new gauge bosons get masses through the interplay of spontaneous symmetry breaking à la Higgs and the Stueckelberg mechanism.

We propose an extension of the Standard Model (SM) based on the $SU(3{)}_C\otimes SU(3{)}_L\otimes U(1{)}_X$ (3-3-1) gauge symmetry and scale invariance. Maintaining the main features of the so-called 3-3-1 models, such as the cancellation of gauge anomalies related to the number of chiral fermion generations, this model exhibits a very compact scalar sector. Only two scalar triplets and one singlet are necessary and sufficient to break the symmetries dynamically via the Coleman-Weinberg mechanism. With the introduction of an Abelian discrete symmetry and assuming a natural hierarchy among the vacuum expectation values of the neutral scalar fields, we show that all particles in the model can get phenomenologically consistent masses. In particular, most of the standard fermion masses are generated via a seesaw mechanism involving some extra heavy fermions introduced for consistency. This mechanism provides a partial solution for the fermion mass hierarchy problem in the SM. Furthermore, the simplicity of the scalar sector allows us to analytically find the conditions for the potential stability up to one-loop level and show how they can be easily satisfied. Some of the new particles, such as the scalars $H$, $H^{\pm }$ and all the non-SM vector bosons, are predicted to get masses around the TeV scale and, therefore, could be produced at the high-luminosity LHC. Finally, we show that the model features a residual symmetry, which leads to the stability of a heavy neutral particle; the latter is expected to show up in experiments as missing energy.

We present the first study of the Abelian-projected gluonic-excitation energies for the static quark-antiquark ($\mathrm{Q}\overline{\mathrm{Q}}$) system in SU(3) lattice QCD at the quenched level, using a ${32}^4$ lattice at $\beta =6.0$. We investigate ground-state and three excited-state $\mathrm{Q}\overline{\mathrm{Q}}$ potentials, using smeared link variables on the lattice. We find universal Abelian dominance for the quark confinement force of the excited-state $\mathrm{Q}\overline{\mathrm{Q}}$ potentials as well as the ground-state potential. Remarkably, in spite of the excitation phenomenon in QCD, we find Abelian dominance for the first gluonic-excitation energy of about 1 GeV at long distances in the maximally Abelian gauge. On the other hand, no Abelian dominance is observed for higher gluonic-excitation energies even at long distances. This suggests that there is some threshold between 1 and 2 GeV for the applicable excitation-energy region of Abelian dominance. Also, we find that Abelian projection significantly reduces the short-distance $1/r$-like behavior in gluonic-excitation energies.

We present the first open-source analysis of parton distribution functions (PDFs) of charged pions using xFitter, an open-source QCD fit framework to facilitate PDF extraction and analyses. Our calculations are implemented at next-to-leading order (NLO) using applgrids generated by the mcfm generator. Using currently available Drell-Yan and photon production data, we find the valence distribution is well constrained; however, the considered data are not sensitive enough to unambiguously determine sea and gluon distributions. Fractions of momentum carried by the valence, sea and gluon components are discussed, and we compare with the results of the JAM collaboration and the GRV group.

We discuss a general diagrammatic description of $n$-point functions in the QCD instanton vacuum that resums planar diagrams, and enforces gauge invariance and spontaneously broken chiral symmetry. We use these diagrammatic rules to derive the pion and kaon quasiparton amplitude and distribution functions at leading order in the instanton packing fraction for large but finite momentum. The instanton and anti-instanton zero modes and nonzero modes are found to contribute to the quasidistributions, but the latter are shown to drop out in the large-momentum limit. The pertinent pion and kaon parton distribution amplitudes and functions are made explicit at the low renormalization scale fixed by the inverse instanton size. Assuming that factorization holds, the pion parton distributions are evolved to higher renormalization scales with one-loop DGLAP evolution and compared to existing data.

Cross sections of the process $e^{+}{e}^{-}\to {\pi }^0{\pi }^{0}J/\psi$ at center-of-mass energies between 3.808 and 4.600 GeV are measured with high precision by using $12.4{\mathrm{fb}}^{-1}$ of data samples collected with the BESIII detector operating at the BEPCII collider facility. A fit to the measured energy-dependent cross sections confirms the existence of the charmoniumlike state $Y(4220)$. The mass and width of the $Y(4220)$ are determined to be $(4220.4\pm 2.4\pm 2.3)$ $\mathrm{MeV}/c^2$ and $(46.2\pm 4.7\pm 2.1)\mathrm{MeV}$, respectively, where the first uncertainties are statistical and the second systematic. The mass and width are consistent with those measured in the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}J/\psi$. The neutral charmonium-like state $Z_c(3900{)}^0$ is observed prominently in the ${\pi }^{0}J/\psi$ invariant-mass spectrum, and, for the first time, an amplitude analysis is performed to study its properties. The spin-parity of $Z_c(3900{)}^0$ is determined to be $J^P=1^{+}$, and the pole position is $(3893.1\pm 2.2\pm 3.0)-i(22.2\pm 2.6\pm 7.0)\mathrm{MeV}/c^2$, which is consistent with previous studies of electrically charged $Z_c(3900{)}^{\pm }$. In addition, cross sections of $e^{+}{e}^{-}\to {\pi }^0{Z}_c(3900{)}^0\to {\pi }^0{\pi }^{0}J/\psi$ are extracted, and the corresponding line shape is found to agree with that of the $Y(4220)$.

The Cachazo-He-Yuan formula was originally proposed to describe on-shell scattering of particles from a single massless field. We present a method to modify it to include several interacting scalar fields, all possessing different masses and possibly off-shell momenta. The method is applied to Yukawa interactions between a number of scalar nucleons and pions, and to the ${\varphi }_1{\varphi }_2{\varphi }_3$ coupling of three different scalar fields. Composite models constructed from existing theories can be used to broaden the scope of the method. The modification is applied to describe Compton scattering from a massive particle and to photon bremsstrahlung. It is also employed to generalize the disk function $Z$ and the sphere function $J$.

Recent observations of anomalous line-of-sight velocity dispersions of two ultradiffuse galaxies (UDGs) provide a stringent test for modified gravity theories. While NGC 1052-DF2 exhibits an extremely low dispersion value ($\sigma \sim {7.8}_{-2.2}^{+5.6}\mathrm{km}/\mathrm{s}$), the reported dispersion value for NGC 1052-DF44 is quite high ($\sigma \sim 41.0\pm 8\mathrm{km}/\mathrm{s}$). For DF2, the dynamical mass is almost equal to the luminous mass suggesting the galaxy have little to no “dark matter” in $\mathrm{\Lambda }\mathrm{CDM}$ whereas DF4 requires a dynamical mass-to-light ratio of $\sim 30$ making it to be almost entirely consists of dark matter. It has been claimed that both these galaxies, marking the extreme points in terms of the estimated dynamical mass-to-light ratio among known galaxies, would be difficult to explain in modified gravity scenarios. Extending the analysis presented in [T. Islam and K. Dutta, Phys. Rev. D 100, 104049 (2019)], we explore the dynamics of DF2 and DF44 within the context of three popular alternative theories of gravity [modified Newtonian dynamics (MOND), Weyl conformal gravity and modified gravity (MOG)] and examine their viability against the dispersion data of DF2 and DF44. We further show that the galactic “radial acceleration relation” (RAR) is consistent with DF44 dispersion data but not with DF2.

In a class of generalized Proca theories, we study the existence of neutron star solutions with a nonvanishing temporal component of the vector field $A_{\mu }$ approaching 0 toward spatial infinity, as they may be the endpoints of tachyonic instabilities of neutron star solutions in general relativity with $A_{\mu }=0$. Such a phenomenon is called spontaneous vectorization, which is analogous to spontaneous scalarization in scalar-tensor theories with nonminimal couplings to the curvature or matter. For the nonminimal coupling $\beta XR$, where $\beta$ is a coupling constant and $X=-A_{\mu }{A}^{\mu }/2$, we show that there exist both 0-node and 1-node vector-field solutions, irrespective of the choice of the equations of state of nuclear matter. The 0-node solution, which is present only for $\beta =-\mathcal{O}(0.1)$, may be induced by some nonlinear effects such as the selected choice of initial conditions. The 1-node solution exists for $\beta =-\mathcal{O}(1)$, which suddenly emerges above a critical central density of star and approaches the general relativistic branch with the increasing central density. We compute the mass $M$ and radius $r_s$ of neutron stars for some realistic equations of state and show that the $M-r_s$ relations of 0-node and 1-node solutions exhibit a notable difference from those of scalarized solutions in scalar-tensor theories. Finally, we discuss the possible endpoints of tachyonic instabilities.

In this paper, we study the shadow produced by rotating black holes with charge in the presence of an anisotropic matter field. We obtain the apparent shape and the corresponding observables characterizing the size, oblateness, and deviation of the center, for different values of the parameters of the model. We compare the new results with those corresponding to the Kerr-Newmann spacetime and we also discuss the observational prospects.

We study the self-force acting on a static charged pointlike particle near a Schwarzschild black hole. We obtain the pointlike particle as a limit of a spacetime describing a big neutral black hole with a small charged massive object nearby. The massive object is modeled by a black hole or a naked singularity. In this fully interacting system the massive object is supported above the black hole by a strut. Such a strut has a nonzero tension which corresponds to the external force compensating the gravitational force and the electromagnetic self-force acting on the massive object. We discuss details of the limiting procedure leading to the pointlike particle situation. As a result, we obtain the standard gravitational force in the static frame of the Schwarzschild spacetime and the electromagnetic self-force. The electromagnetic self-force differs slightly from the classical results in a domain near the horizon. The difference is due to taking into account the influence of the strut on the electromagnetic field. We also demonstrate that higher order corrections to the gravitational force, a sort of gravitational self-force, are not uniquely defined, and they depend on details of the limiting procedure.

We investigate generalized interacting dark matter–dark energy scenarios with a time-dependent coupling parameter, allowing also for freedom in the neutrino sector. The models are tested in the phantom and quintessence regimes, characterized by equations of state, $w_x<-1$ and $w_x>-1$, respectively. Our analyses show that for some of the scenarios, the existing tensions on the Hubble constant $H_0$ and on the clustering parameter $S_8$ can be significantly alleviated. The relief is either due to (a) a dark energy component which lies within the phantom region or (b) the presence of a dynamical coupling in quintessence scenarios. The inclusion of massive neutrinos into the interaction schemes does not affect either the constraints on the cosmological parameters or the bounds on the total number or relativistic degrees of freedom $N_{\mathrm{eff}}$, which are found to be extremely robust and, in general, strongly consistent with the canonical prediction $N_{\mathrm{eff}}=3.045$. The most stringent bound on the total neutrino mass $M_{\nu }$ is $M_{\nu }<0.116\mathrm{eV}$ and it is obtained within a quintessence scenario in which the matter mass-energy density is only mildly affected by the presence of a dynamical dark sector coupling.

Optimal analyses of many signals in the cosmic microwave background (CMB) require map-level extraction of individual components in the microwave sky, rather than measurements at the power spectrum level alone. To date, nearly all map-level component separation in CMB analyses has been performed exclusively using satellite data. In this paper, we implement a component separation method based on the internal linear combination (ILC) approach which we have designed to optimally account for the anisotropic noise (in the 2D Fourier domain) often found in ground-based CMB experiments. Using this method, we combine multifrequency data from the Planck satellite and the Atacama Cosmology Telescope Polarimeter (ACTPol) to construct the first wide-area ($\approx 2100\mathrm{sq}.\mathrm{deg}.$), arcminute-resolution component-separated maps of the CMB temperature anisotropy and the thermal Sunyaev-Zel’dovich (tSZ) effect sourced by the inverse-Compton scattering of CMB photons off hot, ionized gas. Our ILC pipeline allows for explicit deprojection of various contaminating signals, including a modified blackbody approximation of the cosmic infrared background (CIB) spectral energy distribution. The cleaned CMB maps will be a useful resource for CMB lensing reconstruction, kinematic SZ cross-correlations, and primordial non-Gaussianity studies. The tSZ maps will be used to study the pressure profiles of galaxies, groups, and clusters through cross-correlations with halo catalogs, with dust contamination controlled via CIB deprojection. The data products described in this paper are available on LAMBDA.

In general relativity, predictions for observable quantities can be expressed in a coordinate independent way. Nonetheless it may be inconvenient to do so. Using a particular frame may be the easiest way to connect theoretical predictions to measurable quantities. For the cosmological curvature bispectrum such frame is described by the conformal Fermi coordinates. In single field inflation it was shown that going to this frame cancels the squeezed limit of the density perturbation bispectrum calculated in global coordinates. We explore this issue in quasisingle field inflation when the curvaton mass and the curvaton-inflaton mixing are small. In this case, the contribution to the bispectrum from the coordinate transformation to conformal Fermi coordinates is of the same order as that from the inflaton-curvaton interaction term but does not cancel it.

We examine the eigenfrequencies of gravitational waves from the protoneutron stars (PNSs) provided via the core-collapse supernovae, focusing on how the frequencies depend on the dimension of numerical simulations especially for the early phase after core bounce. As expected, we find that the time evolution of gravitational wave frequencies depends strongly on the dimension of numerical simulation as well as the equation of state for high density matter. Even so, we find that the fundamental frequency as a function of PNS average density and the ratio of the specific eigenfrequencies to the fundamental frequency as a function of PNS properties are independent of the dimension of the numerical simulations, where the dependence of the equation of state is also very weak in this early postbounce phase. Thus, one can safely discuss the gravitational wave frequencies of the PNSs as a function of the PNS average density or compactness even with the frequencies obtained from the one dimensional simulations. We also provide phenomenological relation between the compactness and average density as well as the relation among the $f$-, $p$-, and $g$- mode frequencies.

We report on the gravitational-wave signal computed in the context of a three-dimensional simulation of a core-collapse supernova explosion of a $15M_{\odot }$ star. The simulation was performed with our neutrino hydrodynamics code chimera. We detail the gravitational wave strains as a function of time, for both polarizations, and discuss their physical origins. We also present the corresponding spectral signatures. Gravitational wave emission in our model has two key features: low-frequency emission (less than 200 Hz) emanates from the gain layer as a result of neutrino-driven convection and the standing accretion shock instability (SASI), and high-frequency emission (greater than 600 Hz) emanates from the proto–neutron star due to Ledoux convection within it. The high-frequency emission dominates the gravitational wave emission in our model and emanates largely from the convective layer itself, not from the convectively stable layer above it, due to convective overshoot. Moreover, the low-frequency emission emanates from the gain layer itself, not from the proto–neutron star, due to accretion onto it. We provide evidence of the SASI in our model and demonstrate that the peak of our low-frequency gravitational wave emission spectrum corresponds to it. Given its origin in the gain layer, we classify the SASI emission in our model as p-mode emission and assign a purely acoustic origin, not a vortical–acoustic origin, to it. We compare the results of our three-dimensional model analysis with those obtained from the model’s two-dimensional counterpart and find a significant reduction in the strain amplitudes in the former case, as well as significant reductions in all related quantities. Our dominant proto–neutron star gravitational wave emission is not well characterized by emission from surface g modes, complicating the relationship between peak frequencies observed and the mass and radius of the proto–neutron star expressed by analytic estimates under the assumption of surface g-mode emission. We present our frequency normalized characteristic strain along with the sensitivity curves of current- and next-generation gravitational wave detectors. This simple analysis indicates that the spectrum of gravitational wave emission between approximately 20 Hz and approximately 1 kHz, stemming from neutrino-driven convection, the SASI, accretion onto the proto–neutron star, and proto–neutron star convection, will be accessible for a Galactic event.