The molecular assignments to the three $P_c$ states and the similar production mechanism between the ${\mathrm{\Lambda }}_b\to P_c+K$ and $B\to XYZ+K$ convince us the $B$ decaying to a charmonium state plus light mesons could be the appropriate production process to search for the charmoniumlike molecular tetraquarks. In this work, we systematically study the interactions between a charmed (charmed-strange) meson and an anticharmed (anticharm-strange) meson, which include the $D^{(*)}{\overline{D}}^{(*)}$, ${\overline{D}}^{(*)}{\overline{D}}_1$, $D^{(*)}{\overline{D}}_2^{*}$, $D_s^{(*)}{\overline{D}}_s^{(*)}$, $D_s^{(*)}{\overline{D}}_{s0}^{*}$, $D_s^{(*)}{\overline{D}}_{s1}^{\prime }$, $D_s^{(*)}{\overline{D}}_{s1}$, $D_s^{(*)}{\overline{D}}_{s2}^{*}$ systems. After adopting the one-boson-exchange effective potentials, our numerical results indicate that, on one hand, there can exist a serial of isoscalar charmoniumlike $\mathcal{D}\overline{\mathcal{D}}$ and ${\mathcal{D}}_s{\overline{\mathcal{D}}}_s$ molecular states, on the other hand, we can fully exclude the charged charmoniumlike states as the isovector charmoniumlike molecules. Meanwhile, we discuss the two-body hidden-charm decay channels for the obtained $\mathcal{D}\overline{\mathcal{D}}$ and ${\mathcal{D}}_s{\overline{\mathcal{D}}}_s$ molecules, especially the $D^{*}{\overline{D}}^{*}$ molecular tetraquarks. By analyzing the experimental data collected from the $B\to XYZ+K$ and the mass spectrum and two-body hidden-charm decay channels for the obtained $\mathcal{D}\overline{\mathcal{D}}$ and ${\mathcal{D}}_s{\overline{\mathcal{D}}}_s$ molecules, we find several possible hints of the existence of the charmoniumlike molecular tetraquarks, i.e., a peculiar characteristic mass spectrum of the isoscalar $D^{*}{\overline{D}}^{*}$ molecular systems can be applied to identify the charmoniumlike molecule. We look forward to the future experiments like the LHCb, Belle II, and BESIII Collaborations can test our results with more precise experimental data.

We simultaneously incorporate two common extensions of the hadron resonance gas model, namely the addition of extra, unconfirmed resonances to the particle list, and the excluded volume repulsive interactions. We emphasize the complementary nature of these two extensions and identify combinations of conserved charge susceptibilities that allow us to constrain them separately. In particular, ratios of second-order susceptibilities like ${\chi }_{11}^{BQ}/{\chi }_2^B$ and ${\chi }_{11}^{BS}/{\chi }_2^B$ are sensitive only to the baryon spectrum, while fourth-to-second order ratios like ${\chi }_4^B/{\chi }_2^B$, ${\chi }_{31}^{BS}/{\chi }_{11}^{BS}$, or ${\chi }_{31}^{BQ}/{\chi }_{11}^{BQ}$ are mainly determined by repulsive interactions. Analysis of the available lattice results suggests the presence of both the extra states in the baryon-strangeness sector and the repulsive baryonic interaction, with indications that hyperons have a smaller repulsive core than nonstrange baryons. The modified hadron resonance gas model presented here significantly improves the description of lattice QCD susceptibilities at chemical freeze-out and can be used for the analysis of event-by-event fluctuations in heavy-ion collisions.

We present an experimental procedure, based on Meissner effect levitation of neodymium ferromagnets, as a method of measuring the gravitational interactions between milligram masses. The scheme consists of two superconducting lead traps, with a magnet levitating in each trap. The levitating magnets behave as harmonic oscillators and, by carefully driving the motion of one magnet on resonance with the other, we find that it should easily be possible to measure the gravitational field produced by a 4 mg sphere, with the gravitational attraction from masses as small as $30\mu \mathrm{g}$ predicted to be measurable within a realistic measurement time frame. We apply this acceleration sensitivity to one concrete example and show the abilities of testing models of modified Newtonian dynamics.

When dense high-energy lepton bunches collide, the beam particles can experience rest-frame electromagnetic fields which greatly exceed the QED critical one. Here it is demonstrated that beamstrahlung efficiently converts lepton energy to high-energy photons in this so-called supercritical QED regime, as the single-photon emission spectrum exhibits a pronounced peak close to the initial lepton energy. It is also shown that the observation of this high-energy peak in the photon spectrum requires one to mitigate multiple photon emissions during the interaction. Otherwise, the photon recoil induces strong correlations between subsequent emissions which soften the photon spectrum and suppress the peak. The high-energy peak in the photon spectrum constitutes a unique observable of photon emission in the supercritical QED regime and provides decisive advantages for the realization of an efficient multi-TeV laserless gamma-gamma collider based on electron-electron collisions.

We study the leading- (LO) and the next-to-leading-order (NLO) stability of multipole perturbations for a static dielectric M2-brane with spherical topology in the 11-dimensional maximally supersymmetric plane-wave background. We observe a cascade of instabilities that originates from the dipole ($j=1$) and quadrupole ($j=2$) sectors (the only unstable sectors of the LO) and propagates toward all the multipoles of the NLO.

The energy radiated (without the 1.5PN tail contribution which requires a different treatment) by a binary system of compact objects moving in a hyperboliclike orbit is computed in the frequency domain through the second post-Newtonian level as an expansion in the large-eccentricity parameter up to next-to-next-to-leading order, completing the time domain corresponding information (fully known in closed form at the second post-Newtonian of accuracy). The spectrum contains quadratic products of the modified Bessel functions of the first kind (Bessel $K$ functions) with frequency-dependent order (and argument) already at Newtonian level, so preventing the direct evaluation of Fourier integrals. However, as the order of the Bessel functions tends to zero for large eccentricities, a large-eccentricity expansion of the spectrum allows for analytical computation beyond the lowest order.

An exact solution for the bulk five-dimensional geometry is derived for $F(R)$ gravity with nonflat de Sitter 3-branes located at the $M_4\times Z_2$ orbifold boundaries. The corresponding form of $F(R)$ that leads to such an exact solution of the bulk metric is derived, which turns out to have all positive integer powers of $R$. In such a scenario, the stability issue of the modulus (radion field) is analyzed critically for different curvature epochs in both Einstein and Jordan frames. The radion in the effective 4D theory exhibits a phantom epoch, making this model viable for a nonsingular bounce. Simultaneous resolution of the gauge-hierarchy problem is exhibited through the resulting stable value of the radion field in the effective $3+1$-dimensional theory.

We carry out numerical simulations of the gravitational collapse of a rotating perfect fluid with the ultrarelativistic equation of state $P=\kappa \rho$, in axisymmetry in $2+1$ spacetime dimensions with $\mathrm{\Lambda }<0$. We show that for $\kappa \lesssim 0.42$, the critical phenomena are type I, and the critical solution is stationary. The picture for $\kappa \gtrsim 0.43$ is more delicate: for small angular momenta, we find type II phenomena, and the critical solution is quasistationary, contracting adiabatically. The spin-to-mass ratio of the critical solution increases as it contracts, and hence, so does that of the black hole created at the end as we fine-tune to the black-hole threshold. Forming extremal black holes is avoided because the contraction of the critical solution smoothly ends as extremality is approached.

Detection of gravitational waves (GW) from highly eccentric binary black hole (BBH) systems can provide insight into their dynamics and formation. To date, all of the LIGO-Virgo BBH detections have been made using quasicircular templates in their initial discovery. However, recent studies have found some of these systems to be compatible with high eccentricity in the LIGO band, $e_{10\mathrm{Hz}}>0.1$, possibly pointing to a population of sources that are challenging to detect. Current low-latency search methods used with ground-based GW detector data are not well equipped to detect highly eccentric sources. Template-based, matched-filter searches require accurate eccentric waveform models that are computational expensive. Unmodeled burst searches are designed to detected localized excess power and are unable to identify multiple isolated bursts, as would originate from a single highly eccentric BBH. Therefore, we propose a signal-based prior that can be incorporated into an existing GW burst search to target highly eccentric BBHs. Our eccentric burst prior is based on the Newtonian burst model described by [Classical Quantum Gravity 34, 135011 (2017)]. As a proof of concept, we test our method on simulated data and find that for intermediate $\mathrm{SNR}\sim 3–6$ signals using the eccentric burst prior more effectively localizes GW bursts when compared to a uniform prior.

In Paper I, three TAIJI orbital deployments have been proposed to compose alternative LISA-TAIJI networks: TAIJIm (leading the Earth by 20° and $-60°$ inclined with respect to ecliptic plane), TAIJIp (leading the Earth by 20° and $+60°$ inclined), TAIJIc (colocated and coplanar with LISA) with respect to the LISA mission (trailing the Earth by 20° and $+60°$ inclined). And the LISA-TAIJIm network has been identified as the most capable configuration for massive black hole binary observation. In this work, we examine the performance of three networks to the stochastic gravitational wave background (SGWB) especially for the comparison of two eligible configurations, LISA-TAIJIm and LISA-TAIJIp. This investigation shows that the detectability of LISA-TAIJIm is competitive with the LISA-TAIJIp network for some specific SGWB spectral shapes. And the capability of LISA-TAIJIm is also identical to LISA-TAIJIp to separate the SGWB components by determining the parameters of signals. Considering the performances on SGWB and massive black hole binaries observations, the TAIJIm could be recognized as an optimal option to fulfill joint observations with LISA.

Neutron stars (NSs) in scalar-tensor theories of gravitation with the phenomenon of spontaneous scalarization can develop significant deviations from general relativity. Cases with a massless scalar have been studied widely. We compare the NS scalarizations in Damour–Esposito-Farèse theory, Mendes-Ortiz theory, and $\xi$ theory with a massive scalar field. Numerical solutions for slowly rotating NSs are obtained. They are used to construct the x-ray pulse profiles of a pair of extended hot spots on the surface of NSs. We also calculate the tidal deformability for NSs with spontaneous scalarization, which is done for the first time with a massive scalar field. We show the universal relation between the moment of inertia and the tidal deformability. The x-ray pulse profiles, the tidal deformability, and the universal relation may help us to constrain the massive scalar-tensor theories in x-ray and gravitational-wave observations of NSs, including the Neutron star Interior Composition Explorer satellite, the Square Kilometre Array telescope, and LIGO/Virgo/KAGRA laser interferometers.

We study the time delay between two relativistic images due to strong gravitational lensing of the light rays caused by the Kerr and Kerr-Newman black holes. The trajectories of the light rays are restricted on the equatorial plane. Using the known form of the deflection angle in the strong deflection limit (SDL) allows us to analytically develop the formalism for the travel time of the light from the distant source winding around the black hole several times and reaching the observer. We find that the black holes with higher mass or with spin of the extreme black hole potentially have a higher time delay. The effect of the charge of the black hole enhances the time delay between the images lying on the opposite side of the optical axis, resulting from the light rays when one light ray is in the direct orbit and the other is in the retrograde orbit. In contrary, when both light rays travel along either direct or retrograde orbits, giving the images on the same side of the optical axis, the charge effect reduces the time delay between them. We then examine the time delay observations due to the galactic and supermassive black holes, respectively.

When geodesic equations are formulated in terms of an effective potential $\mathcal{U}$, circular orbits are characterized by $\mathcal{U}={\partial }_a\mathcal{U}=0$. In this paper, we consider the case where $\mathcal{U}$ is an algebraic function. Then, the condition for circular orbits defines an $A$-discriminantal variety. A theorem by Rojas and Rusek, suitably interpreted in the context of effective potentials, gives a precise criteria for certain types of spacetimes to contain at most two branches of light rings (null circular orbits), where one is stable and the other one unstable. We identify a few classes of static, spherically symmetric spacetimes for which these two branches occur.

We derive the Hawking radiation spectrum of anyons, namely particles in $(2+1)$—dimension obeying fractional statistics, from a Bañados, Teitelboim, and Zanelli (BTZ) black hole, in the tunneling formalism. We examine ways of measuring the spectrum in experimentally realizable systems in the laboratory.

Perturbation theory of large-scale structures of the Universe at next-to-leading order and next-to-next-to-leading order provides us with predictions of cosmological statistics at subpercent level in the mildly nonlinear regime. Its use to infer cosmological parameters from spectroscopic surveys, however, is hampered by the computational cost of making predictions for a large number of parameters. In order to reduce the running time of the codes, we present a fast scheme in the context of the regularized perturbation theory approach and applied it to power spectra at 2-loop level and bispectra at 1-loop level, including the impact of binning. This method utilizes a Taylor expansion of the power spectrum as a functional of the linear power spectrum around fiducial points at which costly direct evaluation of perturbative diagrams is performed and tabulated. The computation of the predicted spectra for arbitrary cosmological parameters then requires only one-dimensional integrals that can be done within a few minutes. It makes this method suitable for Markov chain Monte-Carlo analyses for cosmological parameter inference.

In order to extract maximal information from neutron-star merger signals, both gravitational and electromagnetic, we need to ensure that our theoretical models/numerical simulations faithfully represent the extreme physics involved. This involves a range of issues, with the finite temperature effects regulating many of the relevant phenomena. As a step toward understanding these issues, we explore the conditions for $\beta$-equilibrium in neutron star matter for the densities and temperatures reached in a binary neutron star merger. Using the results from our out-of-equilibrium merger simulation, we consider how different notions of equilibrium may affect the merger dynamics, raising issues that arise when attempting to account for these conditions in future simulations. These issues are both computational and conceptual. We show that the effects lead to, in our case, a softening of the equation of state in some density regions, and to composition changes that affect processes that rely on deviation from equilibrium, such as bulk viscosity, both in terms of the magnitude and the equilibration timescales inherent to the relevant set of reactions. We also demonstrate that it is difficult to determine exactly which equilibrium conditions are relevant in which regions of the matter due to the dependence on neutrino absorption, further complicating the calculation of the reactions that work to restore the matter to equilibrium.

The origin of ultrahigh-energy cosmic rays (UHECRs) remains a mystery. It has been suggested that UHECRs can be produced by the stochastic acceleration in relativistic jets of gamma-ray bursts (GRBs) at the early afterglow phase. We develop a time-dependent model for proton energization by cascading compressible waves in GRB jets while considering the concurrent effect of the jet’s dynamics and the mutual interactions between turbulent waves and particles. Considering the fast mode of a magnetosonic wave as the dominant particle scatterer and assuming the interstellar medium for the circumburst environment, our numerical results suggest that protons can be accelerated up to ${10}^{19}\mathrm{eV}$ during the early afterglow. An estimation shows that ultrahigh-energy nuclei can easily survive photodisintegration in the external shocks in most cases, thus allowing the acceleration of ${10}^{20}\mathrm{eV}$ cosmic-ray nuclei in the proposed frame. The spectral slope can be as hard as $\mathrm{d}N/\mathrm{d}E\propto E^0$, which is consistent with the requirement for the interpretation of the intermediate-mass composition of the UHECRs as measured by the Pierre Auger Observatory.

We discuss stationary and axisymmetric transmagnetosonic outflows in the magnetosphere of a rotating black hole (BH). Ejected plasma from the plasma source located near the BH is accelerated far away to form a relativistic jet. In this study, the plasma acceleration efficiency and conversion of fluid energy from electromagnetic energy are considered by employing the transfast magnetosonic flow solution derived by Takahashi & Tomimatsu (2008). Considering the parameter dependence of magnetohydrodynamical flows, we search for the parameters of the transmagnetosonic outflow solution to the recent M87 jet observations and obtain the angular velocity values of the magnetic field line and angular momentum of the outflow in the magnetized jet flow. Therefore, we estimate the locations of the outer light surface, Alfvén surface, and separation surface of the flow. We also discuss the electromagnetic energy flux from the rotating BH (i.e., the Blandford–Znajek process), which suggests that the energy extraction mechanism is effective for the M87 relativistic jet.

We perform numerical simulations of fast collective neutrino flavor conversions in an one-dimensional box mimicking a system with the periodic boundary condition in one spatial direction and translation symmetry in the other two dimensions. We evolve the system over several thousands of the characteristic timescale (inverse of the interaction strength) with different initial ${\overline{\nu }}_e$ to ${\nu }_e$ number density ratios and different initial seed perturbations. We find that small scale structures are formed due to the interaction of the flavor waves. This results in a nearly flavor depolarization in a certain neutrino phase space, when averaged over the entire box. Specifically, systems with initially equal number of ${\nu }_e$ and ${\overline{\nu }}_e$ can reach full flavor depolarization for the entire neutrino electron lepton number ($\nu \mathrm{ELN}$) angular spectra. For systems with initially unequal ${\nu }_e$ and ${\overline{\nu }}_e$, flavor depolarization can only be reached in one side of the $\nu \mathrm{ELN}$ spectra, dictated by the net neutrino $e-x$ lepton number conservation. Quantitatively small differences depending on the initial perturbations are also found when different perturbation seeds are applied. Our numerical study here provides new insights for efforts aiming to include impact of fast flavor conversions in astrophysical simulations while calls for better analytical understanding accounting for the evolution of fast flavor conversions.

We discuss the associated $c\overline{c}$ and $l^{+}{l}^{-}$ pairs production in ultraperipheral heavy-ion collisions at high energies. Such a channel provides a novel probe for double-parton scattering (DPS) at small $x$ enabling one to probe the photon density inside the nucleus. We have derived an analog of the standard central $pp$ pocket formula and studied the kinematical dependence of the effective cross section. Taking into account both elastic and nonelastic contributions, we have shown predictions for the DPS $c\overline{c}{l}^{+}{l}^{-}$ production cross section differential in charm quark rapidity and dilepton invariant mass and rapidity for LHC and a future collider.