First-order phase transitions (FOPTs) are ubiquitous in physics beyond the Standard Model (SM). Recently, models with no dimensionful parameters in the tree-level action have been attracting much attention because they can predict a very strong FOPT with ultrasupercooling. In this paper, we study the cosmological signatures of such a supercooling model. As a concrete model, we consider the SM with two additional real scalars $\varphi$ and $S$, which can realize the electroweak symmetry breaking via the Coleman-Weinberg mechanism. One of the additional scalars $S$ can naturally become a dark matter (DM) candidate due to the $Z_2$ symmetry of the action. We study the FOPT of this model and calculate the gravitational save (GW) signals and the thermal relic abundance of $S$ taking the filtered effects into account. Within the envelope approximation, we find that the GW peak amplitude can reach $\sim {10}^{-10}$ around the frequency $f\sim {10}^{-3}\mathrm{Hz}$ for model parameters $(v_{\varphi },{\lambda }_{\varphi S})\sim (200\mathrm{TeV},1.6)$ where $v_{\varphi }$ is the vacuum expectation value of $\varphi$ and ${\lambda }_{\varphi S}$ is the scalar mixing coupling. On the other hand, the filtered DM mechanism only works for $0.8\lesssim {\lambda }_{\varphi S}\lesssim 1$, where the GW peak amplitude is found to be quite small $\lesssim {10}^{-17}$.

We investigate the constraints on early dark energy (EDE) by combining the most recent CMB observations available, ACT DR4, SPT-3G, and Planck2018 (${\ell }_{\mathrm{TT},\max }=1000$) data. This combined CMB dataset favors nonzero EDE fractions and large Hubble constants. The inclusion of $\mathrm{BAO}+\mathrm{Pantheon}$ data has little effect on the results, leads to $H_0=71.6(72.9{)}_{-1.5}^{+2.0}$ and $73.17(72.74{)}_{-0.77}^{+0.55}\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ for axionlike EDE and AdS-EDE, respectively. The axionlike EDE can fit the data significantly better ($\mathrm{\Delta }{\chi }^2\lesssim -10$) than $\mathrm{\Lambda }\mathrm{CDM}$, which is mainly driven by the ACT data. It is found again that if the current $H_0$ measured locally is correct, complete resolution of the Hubble tension seems to be pointing toward a scale invariant Harrison-Zeldovich spectrum of primordial scalar perturbation, i.e., $n_s=1$ for $H_0\sim 73\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$.

In a simplified model including a singlet vectorlike top quark $T$ with charge $|\mathrm{Q}|=2/3$, we investigate the single production of $T$ decaying into $tZ$ at the 14 TeV LHC, 27 TeV high energy LHC (HE-LHC), and 100 TeV hadron-hadron Future Circular Hadron Collider (FCC-hh). In the four flavor scheme, we make detailed detector simulations and the background analysis. We find that the excluding and discovering capability is enhanced obviously with the increase of the collision energy. The model includes only two free parameters, the coupling constant $g^{*}$, and top quark partner mass $m_T$. For the highest integrated luminosity designed, the excluding capability can be given as follows: (1) the LHC can exclude the correlated regions $g^{*}\in [0.085,0.50]$ with $m_T\in [1000\mathrm{GeV},1840\mathrm{GeV}]$ for $\mathcal{L}=3000{\mathrm{fb}}^{-1}$; (2) the HE-LHC can exclude the correlated regions $g^{*}\in [0.035,0.50]$ with $m_T\in [1000\mathrm{GeV},2610\mathrm{GeV}]$ for $\mathcal{L}=15{\mathrm{ab}}^{-1}$; (3) the FCC-hh can exclude the correlated regions $g^{*}\in [0.005,0.50]$ with $m_T\in [1000\mathrm{GeV},4270\mathrm{GeV}]$ for $\mathcal{L}=30{\mathrm{ab}}^{-1}$. Besides, we find that the excluding and discovering regions will be reduced if the narrow width approximation limit is considered.

Particles may be emitted efficiently from the solar interior if they are sufficiently light and weakly coupled to the solar plasma. In a narrow region of phase space, they are emitted with velocities smaller than the escape velocity of the Solar System, thereby populating a gravitationally bound density that can accumulate over the solar lifetime, referred to as a “solar basin.” Detection strategies that can succeed in spite of (or even be enhanced by) the low particle velocities are therefore poised to explore new regions of parameter space when taking this solar population into account. Here we identify “direct deflection” as a powerful method to detect such a population of millicharged particles. This approach involves distorting the local flow of gravitationally bound millicharges with an oscillating electromagnetic field and measuring these distortions with a resonant $LC$ circuit. Since it is easier to distort the flow of slowly moving particles, the signal is parametrically enhanced by the small solar escape velocity near Earth. The proposed setup can probe couplings an order of magnitude smaller than other methods for millicharge masses ranging from 100 to 100 eV and can operate concurrently as a search for sub-GeV millicharged dark matter. The signal power scales as the millicharge coupling to the eighth power, meaning that even with conservative assumptions, direct deflection could begin to explore new regions of parameter space. We also highlight novel features of millicharge solar basins, including those associated with the phase-space distribution and the possibility for the occupation number to vastly exceed that of a thermal distribution.

Thanks to the recent careful revisit of the theoretical prediction of the $B_c$ meson lifetime, the conservative upper bound on the branching ratio (BR) of $\tau \nu$ mode is found to be $\simeq 63\%$ due to the large charm quark mass uncertainty. Although it is well known that a charged Higgs ($H^{-}$) interpretation of the $R_{D^{(*)}}$ anomaly is excluded by the previously proposed bounds, $\mathrm{BR}(B_c\to \tau \nu )\le 30\%$ and $\le 10\%$, $H^{-}$ can still explain the anomaly within $1\sigma$ if we adopt the 63% one. The scalar contribution is also favored by the polarization data $F_L^{D^{*}}$ measured at the Belle. Since the implied NP scale is within the reach of the Large Hadron Collider (LHC), collider searches are powerful tools to test the scenario. For instance, the $\tau \nu$ resonance search has already put the more stringent bound for $m_{H^{-}}\ge 400\mathrm{GeV}$. In this work we revisit the further lighter mass range, $180\mathrm{GeV}\le m_{H^{-}}\le 400\mathrm{GeV}$ which has not been covered yet. We will see that a combination of the conventional stau search and low mass flavor inclusive and bottom flavored dijet resonance searches can place a new limit on the interpretation. We summarize the current status of the low mass region and discuss the future sensitivity in the high luminosity (HL)-LHC based on the existent collider constraints.

The hypothetical dark photon portal connecting the visible and dark sectors of the Universe has received considerable attention in recent years, with a focus on $CP$-conserving kinetic mixing between the Standard Model hypercharge gauge boson and a new ${\mathrm{U}(1)}_X$ gauge boson. In the effective field theory context, one may write nonrenormalizable $CP$-violating kinetic mixing interactions involving the $X$ and ${\mathrm{SU}(2)}_L$ gauge bosons. We construct for the first time a renormalizable model for $CP$-violating kinetic mixing that induces $CP$-violating non-Abelian kinetic mixing at mass dimension 5. The model grows out of the type-III seesaw model, with the lepton triplets containing right-handed neutrinos playing a crucial role in making the model renormalizable and providing a bridge to the origin of the neutrino mass. This scenario also accommodates electron electric dipole moments (EDM) as large as the current experimental bound, making future EDM searches an important probe of this scenario.

In recent years, a growing experimental program has begun to search for sub-GeV dark matter through its scattering with electrons. An associated theoretical challenge is to compute the dark matter scattering rate in experimental targets, and to find materials with large scattering rates. In this paper we point out that, if dark matter scatters through a mediator that couples to electromagnetic charge, then electromagnetic sum rules place limits on the achievable scattering rates. These limits serve as a useful sanity check for calculations, as well as setting a theoretical target for proposed detection methods. Motivated by this analysis, we explore how conductor-dielectric heterostructures can result in enhanced scattering rates compared to bulk conductors, for dark matter masses $\lesssim \mathrm{MeV}$. These effects could be especially important in computing the scattering rates from thin-film targets, e.g., superconducting detectors such as superconducting nanowire single-photon detectors, transition edge sensors, or microwave kinetic inductance detectors, for which the scattering rate could be enhanced by orders of magnitude at low enough dark matter masses, as well as introducing or enhancing directional dependence.

The helicity-dependent strange quark distribution in the proton, $\mathrm{\Delta }s$, is calculated in a nonlocal chiral SU(3) effective field theory. The hadronic proton to meson plus octet or decuplet baryon splitting functions are derived at the one-loop level, with loop integrals rendered finite by correlation functions introduced in the nonlocal Lagrangian. Within the convolution framework, the proton strange helicity distribution is obtained using spin-flavor symmetry to constrain the input valence quark distributions in the hadronic intermediate states. The polarized strange quark distribution is found to be quite small, with the lowest moment of $\mathrm{\Delta }s$ negative, but consistent with recent global QCD analyses.

Decay properties of multistrangeness $\mathrm{\Xi }$ and $\mathrm{\Omega }$ baryon resonances are investigated within the constituent quark model by including relativistic corrections. The strong decay widths of various $\mathrm{\Xi }$ and $\mathrm{\Omega }$ resonances are computed and tested for internal quark configurations to pin down their spin-parity ($J^P$) quantum numbers and internal structures. We found that the Roper-like resonances in the multistrangeness sector have large decay widths bearing resemblances to their siblings in light and heavy baryon sectors. In addition, we obtained the decay ratio for the $\mathrm{\Omega }(2012)$ as $\mathrm{\Gamma }(\mathrm{\Omega }\to \mathrm{\Xi }\overline{K}\pi )/\mathrm{\Gamma }(\mathrm{\Omega }\to \mathrm{\Xi }\overline{K})=4.5\%$, which is consistent with the experimental data when $J^P=3/2^{-}$ is assigned. This observation holds the possibility that the $\mathrm{\Omega }(2012)$ could naturally be explained as a three-quark state in the quark model. The decays of other low-lying $\mathrm{\Xi }$ and $\mathrm{\Omega }$ resonances are systematically analyzed, which would be useful to unveil the structure of these resonances in future experiments.

The $d=2$ critical Ising model is described by an exactly solvable conformal field theory (CFT). The deformation to $d=2+\epsilon$ is a relatively simple system at strong coupling outside of even dimensions. Using novel numerical and analytical conformal bootstrap methods in Lorentzian signature, we show that the leading corrections to the Ising data are more singular than $\epsilon$. There must be infinitely many new states due to the $d$-dependence of conformal symmetry. The linear independence of conformal blocks is central to this bootstrap approach, which can be extended to more rigorous studies of nonpositive systems, such as nonunitary, defect/boundary and thermal CFTs.

The gravitational wave signal emitted during the coalescence of two neutron stars carries information about the stars’ internal structure. During the long inspiral phase the main matter observable is the tidal interaction between the binary components, an effect that can be parametrically modeled with compact-binary solutions to general relativity. After the binary merger the main observable is frequency modes of the remnant, most commonly giving rise to a short-duration signal accessible only through numerical simulations. The complicated morphology and the decreasing detector sensitivity in the relevant frequencies currently hinder detection of the postmerger signal and motivate separate analyses for the premerger and postmerger data. However, planned and ongoing detector improvements could soon put the postmerger signal within reach. In this study we target the whole premerger and postmerger signal without an artificial separation at the binary merger. We construct a hybrid analysis that models the inspiral with templates based on analytical calculations and calibrated to numerical relativity and the postmerger signal with a flexible morphology-independent analysis. Applying this analysis to GW170817 we find, as expected, that the postmerger signal remains undetected. We further study simulated signals and find that we can reconstruct the full signal and simultaneously estimate both the premerger tidal deformation and the postmerger signal frequency content. Our analysis allows us to study neutron star physics using all the data available and directly test the premerger and postmerger signal for consistency thus probing effects such as the onset of the hadron-quark phase transition.

Moment of inertia ($I$), rotational (tidal) Love number (${\lambda }^{(\mathrm{rot})}$), and quadrupole moment ($Q$) of slowly rotating massive neutron stars (NSs) with holographic multiquarks (MQs) core are computed in comparison to pure MQ stars. The chiral effective theory (CET) stiff equation of state (EoS) is used in the crust of the neutron star. As previously established in earlier work, the dimensionless multipole moments $\overline{I},{\overline{\lambda }}^{(\mathrm{rot})}$, and $\overline{Q}$ are found to be independent of the rotation parameters and determined completely by the zeroth-order star profile. Universal “I-Love-Q” relations found by Yagi and Yunes [Science 341, 365 (2013); Phys. Rev. D 88, 023009 (2013)] are mostly preserved even in the presence of the MQ core. The tidal deformation parameter ${\overline{\lambda }}^{(\mathrm{tid})}$ is also explored in connection with $\overline{I},{\overline{\lambda }}^{(\mathrm{rot})},\overline{Q}$, and two kinds of universal I-Love-Q relations are verified. However, the unique kink in the plots of multipoles with respect to mass and compactness of the population of neutron stars can reveal the existence of massive NSs with a MQ core.

Partly motivated by the arrow of time problem in cosmology and the Weyl curvature hypothesis formulated by Roger Penrose, previous works in the literature have proposed—among other possibilities—the square of the Weyl curvature as being the underlying entropy density function of black hole entropy, but the proposal suffers from a few drawbacks. In this work, we propose a new entropy density function also based solely on the Weyl curvature, but adopting some other combinations of curvature invariants. As an improvement we find that our method works for all static black hole solutions in four- and five-dimensional general relativity regardless of whether they are empty space solutions or not. It should also be possible to generalize our method to higher dimensions. This allows us to discuss the physical interpretation of black hole entropy, which remains somewhat mysterious. Extending to modified theories of gravity, our work also suggests that gravitational entropy in some theories is a manifestation of different physical effects since we need to choose different combinations of curvature quantities.

Merger rates of binary black holes, binary neutron stars, and neutron-star–black-hole binaries in the local Universe (i.e., redshift $z=0$), inferred from the Laser Interferometer Gravitational Wave Observatory and Virgo, are $16-130{\mathrm{Gpc}}^{-3}{\mathrm{yr}}^{-1}$, $13-1900{\mathrm{Gpc}}^{-3}{\mathrm{yr}}^{-1}$, and $7.4-320{\mathrm{Gpc}}^{-3}{\mathrm{yr}}^{-1}$, respectively. These rates suggest that there is a significant chance that two or more of these signals will overlap with each other during their lifetime in the sensitivity band of future gravitational-wave detectors such as the Cosmic Explorer and Einstein Telescope. The detection pipelines provide the coalescence time of each signal with an accuracy $\mathcal{O}(10\mathrm{ms})$. We show that by using a prior on the coalescence time from a detection pipeline, it is possible to correctly infer the properties of these overlapping signals with the current data-analysis infrastructure. We study different configurations of two overlapping signals created by nonspinning binaries, varying their time and phase at coalescence, as well as their signal-to-noise ratios. We conclude that, for the scenarios considered in this work, parameter inference is robust provided that their coalescence times in the detector frame are more than $\sim 1–2\mathrm{s}$. Signals whose coalescence epochs lie within $\sim 0.5\mathrm{s}$ of each other suffer from significant biases in parameter inference, and new strategies and algorithms would be required to overcome such biases.

Quasinormal mode (QNM) modeling is an invaluable tool for characterizing remnant black holes, studying strong gravity, and testing general relativity. Only recently have QNM studies begun to focus on multimode fitting to numerical relativity strain waveforms. As gravitational wave observatories become even more sensitive they will be able to resolve higher-order modes. Consequently, multimode QNM fits will be critically important, and in turn require a more thorough treatment of the asymptotic frame at ${\mathcal{I}}^{+}$. The first main result of this work is a method for systematically fitting a QNM model containing many modes to a numerical waveform produced using Cauchy-characteristic extraction (CCE), a waveform extraction technique which is known to resolve memory effects. We choose the modes to model based on their power contribution to the residual between numerical and model waveforms. We show that the all-mode strain mismatch improves by a factor of $\sim {10}^5$ when using multimode fitting as opposed to only fitting the $(2,\pm 2,n)$ modes. Our most significant result addresses a critical point that has been overlooked in the QNM literature: the importance of matching the Bondi-van der Burg-Metzner-Sachs (BMS) frame of the numerical waveform to that of the QNM model. We show that by mapping the numerical waveforms—which exhibit the memory effect—to a BMS frame known as the super rest frame, there is an improvement of $\sim {10}^5$ in the all-mode strain mismatch compared to using a strain waveform whose BMS frame is not fixed. Furthermore, we find that by mapping CCE waveforms to the super rest frame, we can obtain all-mode mismatches that are, on average, a factor of $\sim 4$ better than using the publicly available extrapolated waveforms. We illustrate the effectiveness of these modeling enhancements by applying them to families of waveforms produced by numerical relativity and comparing our results to previous QNM studies.

The canonical approach to black hole entropy in Poincaré gauge theory without matter is extended to include the Maxwell field as a matter source. The new formalism is used to calculate asymptotic charges and entropy of Kerr-Newmann-AdS black holes with torsion. The result implies that the first law, with a nontrivial contribution of the Maxwell field, takes the same form as in general relativity.

This work proposes a set of equations that can be used to numerically compute spacetimes containing a stationary black hole. The formalism is based on the $3+1$ decomposition of General Relativity with maximal slicing and spatial harmonic gauge. The presence of the black hole is enforced using the notion of apparent horizon in equilibrium. This setting leads to the main result of this paper: a set of boundary conditions describing the horizon and that must be used when solving the $3+1$ equations. Those conditions lead to a choice of coordinates that is regular even on the horizon itself. The whole procedure is validated with three different examples chosen to illustrate the great versatility of the method. First, the single rotating black holes are recovered up to very high values of the Kerr parameter. Second, nonrotating black holes coupled to a real scalar field, in the presence of a negative cosmological constant (the so-called Martinez-Troncoso-Zanelli black holes), are obtained. Last, black holes with complex scalar hairs are computed. Eventually, prospects for future work, in particular in contexts where stationarity is only approximate, are discussed.

A cosmological first-order phase transition gravitational wave could provide a novel approach to studying the early Universe. In most cases, the acoustic gravitational wave from the sound wave mechanism is dominant. Considering different sound velocities in symmetric and broken phases, we study sound velocity effects on the acoustic phase transition gravitational wave spectra in the sound shell model. We demonstrate that different sound velocities could obviously modify the peak frequency and peak amplitude of the gravitational wave power spectra. Therefore, taking more realistic sound velocities might provide more accurate predictions for various gravitational wave experiments.