In experiments searching for axionic dark matter, the use of the standard threshold-based data analysis discards valuable information. We present a Bayesian analysis framework that builds on an existing processing protocol [B. M. Brubaker, L. Zhong, S. K. Lamoreaux, K. W. Lehnert, and K. A. van Bibber, Phys. Rev. D 96, 123008 (2017)] to extract more information from the data of coherent axion detectors such as operating haloscopes. The analysis avoids logical subtleties that accompany the standard analysis framework and enables greater experimental flexibility on future data runs. Performing this analysis on the existing data from the HAYSTAC experiment, we find improved constraints on the axion-photon coupling $g_{\gamma }$ while also identifying the most promising regions of parameter space within the $23.15–24.0\mu \mathrm{eV}$ mass range. A comparison with the standard threshold analysis suggests a 36% improvement in scan rate from our analysis, demonstrating the utility of this framework for future axion haloscope analyses.

We study the formation rate of binary black hole mergers formed through gravitational-wave emission between unbound, single black holes in globular clusters. While the formation of these binaries in very dense systems such as galactic nuclei has been well studied, we show here that this process can operate in lower-density stellar systems as well, forming binaries at a rate similar to other proposed pathways for creating eccentric mergers. Recent advances in post-Newtonian cluster dynamics indicate that a large fraction of dynamically assembled binary black holes merge inside their host clusters during weak and strong binary-single and binary-binary interactions, and that these systems may retain measurable eccentricities as they travel through the LIGO and LISA sensitivity bands. Using an analytic approach to modeling binary black holes from globular clusters, we show that the formation of merging binaries from previously unbound black holes can operate at a similar rate to mergers forming during strong binary encounters, and that these binaries inhabit a unique region of the gravitational-wave frequency space which can be identified by proposed deci-Hertz space-based detectors.

We discuss the potential of the $eXTP$ x-ray telescope, in particular its Spectroscopic Focusing Array, Large Area Detector and Wide Field Monitor for the detection of a signal from keV-scale decaying dark matter. We show that the sensitivity of the $eXTP$ is sufficient to improve existing constraints on the mixing angle of the neutrino minimal extension of the Standard Model ($\nu \mathrm{MSM}$) by a factor of 5–10 within the dark matter mass range 2–50 keV, assuming 1% level of systematic uncertainty. We assert that the $eXTP$ will be able to probe previously inaccessible range of $\nu \mathrm{MSM}$ parameters and serve as a precursor for the Athena mission in decaying dark matter searches.

Various theories beyond the Standard Model predict new particles with masses in the sub-eV range with very weak couplings to ordinary matter which can possess spin-dependent couplings to electrons and nucleons. We report null results of a search for possible exotic spin-dependent couplings of the neutron which could be induced by the exchange of light weakly coupled bosons or spin-gravity coupling conducted using a spin-echo neutron spectrometer. We constrain the products $g_A^2$ and $g_A{g}_V$ of the axial vector coupling of the neutron to the matter of the Earth through the exchange of a weakly coupled vector boson for force ranges between the metre scale and the radius of the Earth. We also constrain the constants in some theories of exotic spin-gravity couplings.

New bounds on the electric dipole moment (EDM) of charm and bottom quarks are derived using the stringent limits on their chromo-EDMs. The new limits, $|d_c|<1.5\times {10}^{-21}e\mathrm{cm}$ and $|d_b|<1.2\times {10}^{-20}e\mathrm{cm}$, improve the previous ones by about 3 orders of magnitude. These indirect bounds have implications for different models of new physics, including two-Higgs-doublet, leptoquarks, and supersymmetry models.

We demonstrate that jets from hadronic decays of moderately boosted color-singlet bosons at the LHC can be isolated. The telescoping jet substructure method is used to carve out dominant energy flows along subjets and identify the radiation surrounding the dipole, and it achieves excellent performance in identifying boosted $W$ boson and top quark jets at the LHC energy. We show that telescoping jet variables efficiently isolate subjets, and we compare with standard $N$-prong taggers and isolation cone methods.

We analyze the quasi-two-body decays $B^{+}\to {\pi }^{+}\rho (770,1450{)}^0\to {\pi }^{+}{K}^{+}{K}^{-}$ in the perturbative QCD approach. The results in this work do not support that large branching fractions contributed by the resonances $\rho (770,1450{)}^0$ in the $B^{\pm }\to {\pi }^{\pm }{K}^{+}{K}^{-}$ decays. The virtual contribution for $K^{+}{K}^{-}$ from the tail of the resonance $\rho (770{)}^0$ which has been ignored in the experimental studies is about 1.5 times of the $\rho (1450{)}^0\to K^{+}{K}^{-}$ contribution, with the predicted branching fractions ${\mathcal{B}}_v=(1.31\pm 0.27)\times {10}^{-7}$ and $\mathcal{B}=(8.96\pm 2.61)\times {10}^{-8}$, respectively, for these two subprocesses in the $B^{\pm }\to {\pi }^{\pm }{K}^{+}{K}^{-}$ decays. The absence of $\rho (770{)}^0\to K^{+}{K}^{-}$ for the decay amplitude of a three-body hadronic $B$ decay involving charged kaon pair could probably result in a larger proportion for the contribution from the resonance $\rho (1450{)}^0$ in experimental analysis.

We analyze the flat space limit of 3-point correlators in momentum space for general conformal field theories in even spacetime dimensions, and show they exhibit a double copy structure similar to that found in odd dimensions. In even dimensions, the situation is more complicated because correlators contain branch cuts and divergences which need to be renormalized. We describe the analytic continuation of momenta required to extract the flat space limit, and show that the flat space limit is encoded in the leading singularity of a 1-loop triangle integral which serves as a master integral for 3-point correlators in even dimensions. We then give a detailed analysis of the renormalized correlators in four dimensions where the flat space limit of stress tensor correlators is controlled by the coefficients in the trace anomaly.

We study the quantum channel between two localized first-quantized systems that communicate in $3+1$ dimensional Schwarzschild spacetime via a quantum field. We analyze the information carrying capacity of direct and black hole-orbiting null geodesics as well as of the timelike contributions that arise because the strong Huygens principle does not hold on the Schwarzschild background. We find, in particular, that the nondirect-null and timelike contributions, which do not possess an analog on Minkowski spacetime, can dominate over the direct null contributions. We cover the cases of both geodesic and accelerated emitters. Technically, we apply tools previously designed for the study of wave propagation in curved spacetimes to a relativistic quantum information communication setup, first for generic spacetimes, and then for the case of Schwarzschild spacetime in particular.

Quasinormal modes of scalar field and electromagnetic field in a specific Finslerian-Schwarzschild spacetime have been investigated in this paper. The equations of motion for scalar field and electromagnetic field have been constructed by Finslerian-Laplace operator and divergence operator. The solutions of the equations of motion are presented. The solutions of angular part for scalar field and electromagnetic field are different. The solutions of radial part are numerically analyzed via WKB approximation and finite difference method, which give the quasinormal frequencies and dynamic evolution of quasinormal modes, respectively. The spectrum splitting generated from spherical symmetry breaking of the Finslerian-Schwarzschild spacetime is shown. The analysis of the dynamical evolution of quasinormal modes shows that the Finslerian-Schwarzschild black hole is stable if the Finslerian parameter ${\epsilon }^2<0.8$.

Motivated by the absence of Misner string in the Euclidean Taub-Bolt/NUT solutions with flat horizons, we present a new treatment for studying the thermodynamics of these spactimes. This treatment is based on introducing a new charge, $N=\sigma n$, where $n$ is the nut charge and $\sigma$ is some constant, and its conjugate thermodynamic potential ${\mathrm{\Phi }}_N$. Upon identifying one of the spatial coordinates, the boundary of these solutions contains two annuluslike surfaces in addition to the constant-r surface. For these solutions, we show that these annuli surfaces receive electric, magnetic, and mass/energy fluxes, therefore, they have nontrivial contributions to these conserved charges. Calculating these conserved charges we find, $Q_e=Q_e^{\infty }-2N{\mathrm{\Phi }}_m$, $Q_m=Q_m^{\infty }+2N{\mathrm{\Phi }}_e$ and $\mathfrak{M}=M-2N{\mathrm{\Phi }}_N$, where $Q_e^{\infty }$, $Q_m^{\infty }$, $M$ are electric charge, magnetic charge and mass in the $n=0$ case, while ${\mathrm{\Phi }}_e$ and ${\mathrm{\Phi }}_m$ are the electric and magnetic potentials. The calculated thermodynamic quantities obey the first law of thermodynamics while the entropy is the area of the horizon. Furthermore, all these quantities obey Smarr’s relation. We show the consistency of these results through calculating the Hamiltonian and its variation which reproduces the first law.

We perform a systematic analysis of dark matter production during postinflationary reheating. Following the period of exponential expansion, the inflaton begins a period of damped oscillations as it decays. These oscillations and the evolution of temperature of the thermalized decay products depend on the shape of the inflaton potential $V(\mathrm{\Phi })$. We consider potentials of the form, ${\mathrm{\Phi }}^k$. Standard matter-dominated oscillations occur for $k=2$. In general, the production of dark matter may depend on either (or both) the maximum temperature after inflation, or the reheating temperature, where the latter is defined when the Universe becomes radiation dominated. We show that dark matter production is sensitive to the inflaton potential and depends heavily on the maximum temperature when $k>2$. We also consider the production of dark matter with masses larger than the reheating temperature.

Nongravitational interaction between dark matter and dark energy has been considered in a spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) universe. The interaction rate is assumed to be linear in the energy densities of dark matter and dark energy and it is also proportional to the Hubble rate of the FLRW universe. This kind of interaction model leads to an autonomous linear dynamical system, and depending on the coupling parameters, could be solved analytically by calculating the exponential of the matrix, defining the system. We show here that such interaction rate has a very deep connection with some well-known cosmological theories. We then investigate the theoretical bounds on the coupling parameters of the interaction rate in order that the energy densities of the dark sector remain positive throughout the evolution of the universe and asymptotically converge to zero at very late times. Our analyses also point out that such linear interacting model may encounter with finite time future singularities depending on the coupling parameters as well as the dark energy state parameter.

The identification of electromagnetic emission from gravitational-wave sources typically requires multiple follow-up observations due to the limited fields of view of follow-up observatories compared to the poorly localized direction of gravitational waves. Gravitational-wave localization regions are typically covered with multiple telescope pointings using a “honeycomb” structure, which is optimal only on an infinite, flat surface. Here we present a machine-learning algorithm which uses genetic algorithms along with Broyden-Fletcher-Goldfarb-Shanno optimization to find an optimal configuration of tiles to cover the gravitational-wave sky localization area on a spherical surface.

The observation of binary neutron star merger GW170817, along with its optical counterpart, provided the first constraint on the Hubble constant $H_0$ using gravitational wave standard sirens. When no counterpart is identified, a galaxy catalog can be used to provide the necessary redshift information. However, the true host might not be contained in a catalog which is not complete out to the limit of gravitational-wave detectability. These electromagnetic and gravitational-wave selection effects must be accounted for. We describe and implement a method to estimate $H_0$ using both the counterpart and the galaxy catalog standard siren methods. We perform a series of mock data analyses using binary neutron star mergers to confirm our ability to recover an unbiased estimate of $H_0$. Our simulations used a simplified universe with no redshift uncertainties or galaxy clustering, but with different magnitude-limited catalogs and assumed host galaxy properties, to test our treatment of both selection effects. We explore how the incompleteness of catalogs affects the final measurement of $H_0$, as well as the effect of weighting each galaxy’s likelihood of being a host by its luminosity. In our most realistic simulation, where the simulated catalog is about three times denser than the density of galaxies in the local universe, we find that a 4.4% measurement precision can be reached using galaxy catalogs with 50% completeness and $\sim 250$ binary neutron star detections with sensitivity similar to that of Advanced LIGO’s second observing run.

The question of how to efficiently formulate Hamiltonian gauge theories is experiencing renewed interest due to advances in building quantum simulation platforms. We introduce a reformulation of an SU(2) Hamiltonian lattice gauge theory—a loop-string-hadron (LSH) formulation—that describes dynamics directly in terms of its loop, string, and hadron degrees of freedom, while alleviating several disadvantages of quantum simulating the Kogut-Susskind formulation. This LSH formulation transcends the local loop formulation of $d+1$-dimensional lattice gauge theories by incorporating staggered quarks, furnishing the algebra of gauge-singlet operators, and being used to reconstruct dynamics between states that have Gauss’s law built in to them. LSH operators are then factored into products of “normalized” ladder operators and diagonal matrices, priming them for classical or quantum information processing. Self-contained expressions of the Hamiltonian are given up to $d=3$. The LSH formalism makes little use of structures specific to SU(2), and its conceptual clarity makes it an attractive approach to apply to other non-Abelian groups like SU(3).

We study the leading-twist quasi parton distribution function (quasi-PDF) and quasigeneralized parton distribution (quasi-GPD) of the pion meson by using a spectator model. We consider the case where the quasifunctions are defined via inserting the matrix ${\gamma }_z$ in the spacial correlation functions. We obtain the analytical expressions for the quasi-PDF and quasi-GPD. The numerical results of the quasifunctions are calculated from the parameters obtained by fitting the model result to the known parametrization. Particularly, we investigate the hadron momentum dependence of the quasifunctions as well as compare the quasidistributions to the standard functions at different hadron momentum. We find that in the region $x>0.2$, the quasidistribution are similar to the standard distributions in size and shape when the hadron momentum is larger than 2 GeV. Our study thus supports the idea of using quasidistributions to obtain standard distributions.

In Hoyos et al. [Phys. Rev. Lett. 117, 032501 (2016)], a holographic $\mathrm{D}3/\mathrm{D}7$ system was used to describe a deconfined yet massive quark phase of QCD at finite density, concluding that the equation of state of such a phase was not stiff enough to support exotic dense stars. That analysis used a hard quark mass to represent the dynamical mass and assumed a conformal gauge background. Here, we phenomenologically adjust the $\mathrm{D}3/\mathrm{D}7$ system to include a running anomalous dimension for the quark condensate. This introduces a dynamical mechanism for chiral symmetry breaking, yet the model still has a deconfined massive phase at intermediate densities. We show that these systems, dependent on the running profile in the deep IR, generate much stiffer equations of state and nonmonotonic behavior in the speed of sound. The results suggest that these equations of state may be closer to supporting hybrid stars with quark cores.