Next-generation gravitational-wave detectors will provide unprecedented sensitivity to inspiraling binary neutron stars and black holes, enabling detections at the peak of star formation and beyond. However, the signals from these systems will last much longer than those in current detectors, and overlap in both time and frequency, leading to increased computational cost to search for them with standard matched filtering analyses, and a higher probability that they are observed in the presence of non-Gaussian noise. We therefore present a method to search for gravitational waves from compact binary inspirals in next-generation detectors that is computationally efficient and robust against gaps in data collection and noise nonstationarities. Our method, based on the Hough transform, finds tracks in the time/frequency plane of the detector that uniquely describe specific inspiraling systems. We find that we could detect $\sim 5$ overlapping, intermediate-strength signals (matched-filter signal-to-noise ratio $\rho \approx 58$) without a sensitivity loss. Additionally, we demonstrate that our method can enable multimessenger astronomy: using only low frequencies (2–20 Hz), we could warn astronomers $\sim 2.5$ hours before a GW170817-like merger at 40 Mpc and provide a sky localization of $\sim 20{\mathrm{deg}}^2$ using only one “L” of Einstein Telescope. Additionally, assuming that primordial black holes (PBHs) exist, we derive projected constraints on the fraction of dark matter they could compose, $f_{\mathrm{PBH}}\sim {10}^{-6}–{10}^{-4}$, for $\sim 1–0.1M_{\odot }$ equal-mass systems, respectively, using a rate suppression factor $f_{\sup }=2.5\times {10}^{-3}$. Comparing matched filtering searches to our proposed method at a fixed sensitivity, we find a factor of $\sim 10–50$ speedup when we begin an analysis at a frequency of 5 Hz up to 12 Hz for a system with a chirp mass between $\mathcal{M}\in [1,2]M_{\odot }$.

Using corsika simulations, we investigate the mass sensitivity of cosmic-ray air-shower observables for sites at the South Pole and Malargüe, Argentina, the respective locations of the IceCube Neutrino Observatory and the Pierre Auger Observatory. Exact knowledge of observables from air-shower simulations was used to study the event-by-event mass separation between proton, helium, oxygen, and iron primary cosmic rays with a Fisher linear discriminant analysis. Dependencies on the observation site as well as the energy and zenith angle of the primary particle were studied in the ranges from ${10}^{16.0}–{10}^{18.5}\mathrm{eV}$ and 0° to 60°; they are mostly weak and do not change the qualitative results. Promising proton-iron mass separation is achieved using combined knowledge of all studied observables, also when typical reconstruction uncertainties are accounted for. However, even with exact measurements, event-by-event separation of intermediate-mass nuclei is challenging and better methods than the Fisher discriminant and/or the inclusion of additional observables will be needed. As an individual observable, high-energy muons ($>500\mathrm{GeV}$) provide the best event-by-event mass discrimination, but the combination of muons of any energy and $X_{\max }$ provides already a high event-by-event separation between proton-iron primaries at both sites. We also confirm that the asymmetry and width parameters of the air-shower longitudinal profile, $R$ and $L$, are mass sensitive. Only $R$ seems to be suitable for event-by-event mass separation, but $L$ can potentially be used to statistically determine the proton-helium ratio. Overall, our results motivate the coincident measurement of several air-shower observables, including at least $X_{\max }$ and the sizes of the muonic and electromagnetic shower components, for the next generation of air-shower experiments.

In this paper, the new particle $X(3842)$ discovered by the LHCb Collaboration is identified to be the ${\psi }_3(1^3{D}_3)$ state. We study its strong decays with the combination of the Bethe-Salpeter method and the ${{}^{3}P}_0$ model. Its electromagnetic (EM) decay is also calculated by the Bethe-Salpeter method within the Mandelstam formalism. The strong decay widths are $\mathrm{\Gamma }[X(3842)\to D^0{\overline{D}}^0]=1.27\mathrm{MeV}$ and $\mathrm{\Gamma }[X(3823)\to D^{+}{D}^{-}]=1.08\mathrm{MeV}$, and the ratio is $\mathcal{B}[X(3842)\to D^{+}{D}^{-}]/\mathcal{B}[X(3823)\to D^0{\overline{D}}^0]=0.84$. The EM decay width is $\mathrm{\Gamma }[X(3842)\to {\chi }_{c2}\gamma ]=0.29\mathrm{MeV}$. We also estimate the total width to be 2.87 MeV, which is in good agreement with the experimental data ${2.79}_{-0.86}^{+0.86}\mathrm{MeV}$. Since the used relativistic wave functions include different partial waves, we also study the contributions of different partial waves in electromagnetic decay.

We perform a global analysis of a vectorlike extension of the Standard Model, which also features additional doublet and singlet scalars. The usual Yukawa interactions are forbidden in this setup by an extra U(1) global symmetry and the masses of the second and third family quarks and leptons are generated via the mixing with the vectorlike sector. We identify three best-fit benchmark scenarios which satisfy the constraints imposed by the stability of the scalar potential, the perturbativity of the coupling constants, the measurement of the muon anomalous magnetic moment and the nonobservation of the flavor violating tau decays. We show that dominant contributions to the muon ($g-2$) originate in this model from the charged Higgs/neutral lepton one-loop diagrams, thus correcting an inaccurate statement than can be found in the literature. We also perform a detailed LHC analysis of the benchmark scenarios. We investigate the experimental constraints stemming from direct searches for vectorlike quarks, vectorlike leptons, and exotic scalars. While we show that the model is not currently tested by any collider experiment, we point out that decays of a heavy Higgs boson into two tau leptons may offer a smoking gun signature for the model verification in upcoming runs at the LHC.

We study weak isosinglet vectorlike leptons that decay through a small mixing with the tau lepton, for which the discovery and exclusion reaches of the Large Hadron Collider and future proposed hadron colliders are limited. We show how an $e^{+}{e}^{-}$ collider may act as a discovery machine for these ${\tau }^{\prime }$ particles, demonstrate that the ${\tau }^{\prime }$ mass peak can be reconstructed in a variety of distinct signal regions, and explain how the ${\tau }^{\prime }$ branching ratios may be measured.

We present a feasibility study to probe quantum entanglement and Bell inequality violation in the process ${\mathrm{e}}^{+}{\mathrm{e}}^{-}\to {\tau }^{+}{\tau }^{-}$ at a center-of-mass energy of $\sqrt{s}=10.579\mathrm{GeV}$. The sensitivity of the analysis is enhanced by applying a selection on the scattering angle $\vartheta$ in the ${\tau }^{+}{\tau }^{-}$ center-of-mass frame. We analyze events in which both $\tau$ leptons decay to hadrons, using a combination of decay channels ${\tau }^{-}\to {\pi }^{-}{\nu }_{\tau }$, ${\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau }$, and ${\tau }^{-}\to {\pi }^{-}{\pi }^{+}{\pi }^{-}{\nu }_{\tau }$. The spin orientation of the $\tau$ leptons in these decays is reconstructed using the polarimeter-vector method. Assuming a dataset of 200 million ${\tau }^{+}{\tau }^{-}$ events and accounting for experimental resolutions, we expect the observation of quantum entanglement and Bell inequality violation by the Belle-II experiment will be possible with a significance well in excess of five standard deviations.

The observation of gravitational waves opens up a new window to probe the universe and the nature of the gravitational field itself. As a result, they serve as a new and promising tool to not only test our current theories but to study different models that go beyond our current understanding. In this paper, inspired by recent successes in scalar and Maxwell electrodynamics, we analyze the role played by the (quantum) Unruh effect on the production of both classical and quantum gravitational waves by a uniformly accelerated mass. In particular, we show the fundamental role played by zero-energy (Rindler) gravitons in building up the gravitational radiation, as measured by inertial observers, emitted by the body.

Pseudospectral analyses have broadened our understanding of ringdown waveforms from binary remnants by providing insight into both the stability of their characteristic frequencies under environmental perturbations, as well as the underlying transient and nonmodal phenomenology that a mode analysis may miss. In this work, we present the pseudospectrum of scalar perturbations on spherically symmetric black holes in de Sitter spacetimes. We expand upon previous analyses in this setting by calculating the pseudospectrum of Reissner-Nordström-de Sitter black holes and revisit results regarding the stability of quasinormal modes under perturbations in several cases. Of particular note is the case of scalar quasinormal modes with angular parameter $\ell =0$, which possess a zero mode related to the presence of a cosmological horizon. We show that the nontrivial eigenfunction associated to this mode has a vanishing energy norm, which poses a challenge in quantifying the magnitude of external perturbations to the wave equation’s potential, as well as in calculating the pseudospectrum. Nonetheless, we present results that suggest that the spectral instability manifestation of $\ell =0$ scalar quasinormal modes is qualitatively the same as in other cases, in contrast to recent claims. We also analyze the stability of the fundamental mode for $\ell \ge 1$, finding it to be spectrally stable, except for certain configurations in which a perturbation leads to a discontinuous overtaking of the fundamental unperturbed purely-imaginary mode by a perturbed complex quasinormal mode.

We present a first complete implementation of an effective-one-body (EOB) model for extreme-mass-ratio inspirals (EMRIs) that incorporates aligned spins (on both the primary and the secondary) as well as orbital eccentricity. The model extends TEOBResumS-Dalí for these binaries by (i) recasting conservative first-order gravitational self-force (1GSF) information in the resummed EOB potentials, (ii) employing a post-Newtonian (PN) $3^{+19}\mathrm{PN}$-accurate (3PN comparable-mass terms hybridized with test-particle terms up to 22PN relative order) expression for the gravitational-wave flux at infinity, and (iii) using an improved implementation of the horizon flux that better approximates its test-mass representation. With respect to our previous work [A. Albertini et al., Comparing second-order gravitational self-force and effective one body waveforms from inspiralling, quasicircular and nonspinning black hole binaries. II. The large-mass-ratio case, Phys. Rev. D 106, 084062 (2022).], we demonstrate that the inclusion of the $3^{+19}\mathrm{PN}$-accurate $\ell =9$ and $\ell =10$ modes in the flux at infinity significantly improves the model’s agreement with second-order accurate GSF (2GSF) circular waveforms. For a standard EMRI with mass ratio $q\equiv m_1/m_2=5\times {10}^4$ and $m_2=10M_{\odot }$, the accumulated EOB/2GSF dephasing is $\lesssim \mathrm{rad}$ for $\sim 1\mathrm{yr}$ of evolution, which is consistent with the standard accuracy requirements for EMRIs. We also showcase the generation of eccentric and spinning waveforms and discuss future extensions of our EOB towards a physically complete model for EMRIs.

We introduce a nonperturbative method to constrain the amplitude of local-type primordial non-Gaussianity ($f_{\mathrm{NL}}$) using squeezed configurations of the CMB lensing convergence and cosmic shear bispectra. First, we use cosmological consistency relations to derive a model for the squeezed limit of angular auto- and cross-bispectra of lensing convergence fields in the presence of $f_{\mathrm{NL}}$. Using this model, we perform a Fisher forecast with specifications expected for upcoming CMB lensing measurements from the Simons Observatory and CMB-S4, as well as cosmic shear measurements from a Rubin $\mathrm{LSST}/Euclid$-like experiment. Assuming a minimum multipole ${\ell }_{\min }=10$ and maximum multipole ${\ell }_{\max }=1400$, we forecast ${\sigma }_{f_{\mathrm{NL}}}=175$ (95) for Simons Observatory (CMB-S4). Our forecasts improve considerably for an $\mathrm{LSST}/Euclid$-like cosmic shear experiment with three tomographic bins and ${\ell }_{\min }=10$ and ${\ell }_{\max }=1400$ (5000) with ${\sigma }_{f_{\mathrm{NL}}}=31$ (16). A joint analysis of CMB-S4 lensing and $\mathrm{LSST}/Euclid$-like shear yields little gain over the shear-only forecasts; however, we show that a joint analysis could be useful if the CMB lensing convergence can be reliably reconstructed at larger angular scales than the shear field. The method presented in this work is a novel and robust technique to constrain local primordial non-Gaussianity from upcoming large-scale structure surveys that is completely independent of the galaxy field (and therefore any nuisance parameters such as $b_{\varphi }$), thus complementing existing techniques to constrain $f_{\mathrm{NL}}$ using the scale-dependent halo bias.

We revisit the one-loop corrections on cosmic microwave background scale perturbations induced from small-scale modes in single field models which undergo a phase of ultraslow-roll inflation. There were concerns that large loop corrections are against the notion of the decoupling of scales and that they are canceled out once the boundary terms are included in the Hamiltonian. We highlight that the nonlinear coupling between the long and short modes and the modulation of the short mode power spectrum by the long mode are the key physical reasons behind the large loop corrections. In particular, in order for the modulation by the long mode to be significant there should be a strong scale-dependent enhancement in the power spectrum of the short mode, which is the hallmark of the ultraslow-roll inflation. We highlight the important roles played by the would-be decaying mode which were not taken into account properly in recent works claiming loop cancellation. We confirm the original conclusion that loop corrections are genuine and that they can be dangerous for primordial black hole formation unless the transition to the final attractor phase is mild.

In the preceding article, we introduce 21cmfirstclass, a new code for computing the 21-cm anisotropies, assembled from the merger of the two popular codes 21cmfast and class. Unlike the standard 21cmfast, which begins at $z=35$ with homogeneous temperature and ionization boxes, our code begins its calculations from recombination, evolves the signal through the dark ages, and naturally yields an inhomogeneous box at $z=35$. In this paper, we validate the output of 21cmfirstclass by developing a new theoretical framework which is simple and intuitive on the one hand, but robust and precise on the other hand. As has been recently claimed, using consistent inhomogeneous initial conditions mitigates inaccuracies, which according to our analysis can otherwise reach the $\mathcal{O}(20\%)$ level. On top of that, we also show for the first time that 21cmfast overpredicts the 21-cm power spectrum at $z\gtrsim 20$ by another $\mathcal{O}(20\%)$, due to the underlying assumption that ${\delta }_b={\delta }_c$, namely that the density fluctuations in baryons and cold dark matter are indistinguishable. We propose an elegant solution to this discrepancy by introducing an appropriate scale-dependent growth factor into the evolution equations. Our analysis shows that this modification will ensure subpercent differences between 21cmfirstclass and the Boltzmann solver camb at $z\le 50$ for all scales between the horizon and the Jeans scale. This will enable 21cmfirstclass to consistently and reliably simulate the 21-cm anisotropies both in the dark ages and cosmic dawn, for any cosmology.

In this work we present 21cmfirstclass, a modified version of 21cmfast, the most popular code in the literature for computing the inhomogeneities of the 21-cm signal. Our code uses the public cosmic microwave background (CMB) Boltzmann code class, to establish consistent initial conditions at recombination for any set of cosmological parameters and evolves them throughout the dark ages, cosmic dawn, the epoch of heating and reionization. We account for inhomogeneity in the temperature and ionization fields throughout the evolution, crucial for a robust calculation of both the global 21-cm signal and its fluctuations. We demonstrate how future measurements of the CMB and the 21-cm signal can be combined and analyzed with 21cmfirstclass to obtain constraints on both cosmological and astrophysical parameters and examine degeneracies between them. As an example application, we show how 21cmfirstclass can be used to study cosmological models that exhibit nonlinearities already at the dark ages, such as scattering dark matter (SDM). For the first time, we present self-consistent calculations of the 21-cm power spectrum in the presence of SDM during the nonlinear epoch of cosmic dawn.

Primordial black holes (PBHs) are a compelling candidate for dark matter (DM). There remain significant parameter spaces to be explored despite current astrophysical observations setting strong limits. Utilizing advanced MeV observation instruments, we have statistically established the upper limit of Hawking radiation emitted by PBHs in DM-dense systems, such as galaxy clusters or dwarf galaxies. These results can set a stringent upper limit on the ratio of PBH to DM, expressed as $f_{\mathrm{PBH}}$. Our results highlight the efficacy of MeV observations in DM-dense environments. The constraints on $f_{\mathrm{PBH}}$ for PBHs in the mass range of ${10}^{16}–{10}^{17}\mathrm{g}$ can be improved significantly compared with the current observations.

A number of discrepancies have emerged between lattice computations and data-driven dispersive evaluations of the RBC/UKQCD intermediate-window-hadronic contribution to the muon anomalous magnetic moment. It is therefore interesting to obtain data-driven estimates for the light-quark-connected and strange-plus-disconnected components of this window quantity, allowing for a more detailed comparison between the lattice and data-driven approaches. The aim of this paper is to provide these estimates, extending the analysis to several other window quantities, including two windows designed to focus on the region in which the two-pion contribution is dominant. Clear discrepancies are observed for all light-quark-connected contributions considered, while good agreement with lattice results is found for strange-plus-disconnected contributions to the quantities for which corresponding lattice results exist. The largest of these discrepancies is that for the RBC/UKQCD intermediate window, where, as previously reported, our data-driven result, $a_{\mu }^{W1,\mathrm{lqc}}=198.9(1.1)\times {10}^{-10}$, is in significant tension with the results of 8 different recent lattice determinations. Our strategy is the same as recently employed in obtaining data-driven estimates for the light-quark-connected and strange-plus-disconnected components of the full leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment. Updated versions of those earlier results are also presented, for completeness.

We explore a scenario of high-scale supersymmetry where all supersymmetric particles except gauginos stay at a high-energy scale $M_{\mathrm{SUSY}}$ that is much larger than the reheating temperature $T_{\mathrm{RH}}$. The dark matter is dominated by a bino component with mass around the electroweak scale and the observed relic abundance is mainly generated by the freeze-in process during the early Universe. Considering the various constraints, we identify two available scenarios in which the supersymmetric sector at an energy scale below $T_{\mathrm{RH}}$ consists of (a) bino or (b) bino and wino. Typically, for a bino mass around 0.1–1 TeV and a wino mass around 2 TeV, we find that $M_{\mathrm{SUSY}}$ should be around ${10}^{13-14}\mathrm{GeV}$ with $T_{\mathrm{RH}}$ around ${10}^{4-6}\mathrm{GeV}$.

We calculate the pion scattering amplitude at nonzero temperature and nonzero ${\mu }_5$, the chemical potential associated to chiral imbalance in a locally $P$-breaking scenario. The amplitude is calculated up to next-to-leading order in Chiral Perturbation Theory and is unitarized with the Inverse Amplitude Method to generate the poles of the $f_0(500)$ and $\rho (770)$ resonances. Within the saturation approach, the thermal $f_0(500)$ pole allows to determine $T_c({\mu }_5)$, the transition temperature for chiral symmetry restoration. Our results confirm the growing behavior of $T_c({\mu }_5)$ found in previous works and, through a fit to lattice results, we improve the uncertainty range of the low-energy constants associated to ${\mu }_5$ corrections in the chiral Lagrangian. The results for the $\rho (770)$ pole are compatible with previous works regarding the dilepton yield in heavy-ion collisions.

Based on a data sample of $(2712.4\pm 14.3)\times {10}^6\psi (3686)$ events collected with the BESIII detector at the BEPCII collider, the M1 transition $\psi (3686)\to \gamma {\eta }_c(2S)$ with ${\eta }_c(2S)\to K\overline{K}\pi$ is studied, where $K\overline{K}\pi$ is $K^{+}{K}^{-}{\pi }^0$ or $K_S^0{K}^{\pm }{\pi }^{\mp }$. The mass and width of the ${\eta }_c(2S)$ are measured to be $(3637.8\pm 0.8(\mathrm{stat})\pm 0.2(\mathrm{syst}))\mathrm{MeV}/c^2$ and $(10.5\pm 1.7(\mathrm{stat})\pm 3.5(\mathrm{syst}))\mathrm{MeV}$, respectively. The product branching fraction $\mathcal{B}(\psi (3686)\to \gamma {\eta }_c(2S))\times \mathcal{B}({\eta }_c(2S)\to K\overline{K}\pi )$ is determined to be $(0.97\pm 0.06(\mathrm{stat})\pm 0.09(\mathrm{syst}))\times {10}^{-5}$. Using $\mathcal{B}({\eta }_c(2S)\to K\overline{K}\pi )=(1.86_{-0.49}^{+0.68})\%$, we obtain the branching fraction of the radiative transition to be $\mathcal{B}(\psi (3686)\to \gamma {\eta }_c(2S))=(5.2\pm 0.3(\mathrm{stat})\pm 0.5(\mathrm{syst}{)}_{-1.4}^{+1.9}(\mathrm{extr}))\times {10}^{-4}$, where the third uncertainty is due to the quoted $\mathcal{B}({\eta }_c(2S)\to K\overline{K}\pi )$.

The stringy realization of generalized symmetry operators involves wrapping “branes at infinity”. We argue that in the case of continuous (as opposed to discrete) symmetries, the appropriate objects are fluxbranes. We use this perspective to revisit the phase structure of Verlinde’s monopole, a proposed particle satisfies the Bogomol’nyi-Prasad-Sommerfield (BPS) condition when gravity is decoupled, but is non-BPS and metastable when gravity is switched on. Geometrically, this monopole is obtained from branes wrapped on locally stable but globally trivial cycles of a compactification geometry. The fluxbrane picture allows us to characterize electric (respectively magnetic) confinement (respectively screening) in the 4D theory as a result of monopole decay. In the presence of the fluxbrane, this decay also creates lower-dimensional fluxbranes, which in the field theory is interpreted as the creation of an additional topological field theory sector.

We construct a bulk spacetime from a boundary conformal field theory, $O(N)$ free scalar model, at finite temperature using a smearing technique, called a conformal flow. The bulk metric is constructed from the thermal two-point function of the smeared boundary elementary field in such a way that it can be interpreted as an information metric associated with the boundary thermofield double state. Near the boundary (UV region), an asymptotically anti–de Sitter (AdS) spacetime is obtained with a leading order perturbation of scalar mode. Based on the falloff behavior of the perturbations and the $O(N)$ symmetry in the conformal field theory, we argue that the corresponding bulk theory is a modified gravity with scalar mode such as $f(R)$ gravity rather than Einstein’s general relativity coupled minimally to matter fields. Moving to the Einstein frame, we show that the metric is asymptotically the same as the AdS black brane solution. On the other hand, deep in the bulk (IR region), the spacetime turns out to be conformally equivalent to the near horizon limit of AdS extremal black brane, though it is no longer a solution of $f(R)$ gravity, and hence more general classes of modified gravity need to be considered.