We analyze the mass spectrum of the charged and neutral Higgs bosons in the framework of the two Higgs doublet model (2HDM) in the light of the precision measurement of the $W$ boson mass by the CDF collaboration. We have considered the most general 2HDM potential with explicit $CP$ violation in the Higgs basis which contains the three $CP$-mixed neutral mass eigenstates $H_1$, $H_2$, and $H_3$ with $M_{H_1}\le M_{H_2}\le M_{H_3}$. The high-precision CDF measurement of the $W$ boson mass is characterized by the large positive value of the $T$ parameter. By identifying the lightest neutral Higgs boson $H_1$ as the SM-like one discovered at the LHC, we find that it is necessary to have the mass splitting between the charged Higgs boson $H^{\pm }$ and the second heaviest neutral one $H_2$ to accommodate the sizable positive deviation of the $T$ parameter from its SM value of 0. By combining the mass splitting between $H^{\pm }$ and $H_2$ with the theoretical constraints from the perturbative unitarity and for the Higgs potential to be bounded from below, we implement comprehensive analysis of the mass spectrum of the heavy Higgs bosons taking account of the effects of deviation from the alignment limit and also the mass splitting between $H_3$ and $H_2$. We further analyze the behavior of the heavy-Higgs mass spectrum according to the variation of the $T$ parameter. Finally, concentrating on the heavy mass region $M\equiv (M_{H_2}+M_{H^{\pm }})/2\gtrsim 500\mathrm{GeV}$ in which we find a mass hierarchy of $M\gg M_{H_1}\sim |\mathrm{\Delta }|\gtrsim \delta$ with $\mathrm{\Delta }\equiv M_{H_2}-M_{H^{\pm }}$ and $\delta \equiv M_{H_3}-M_{H_2}$, we discuss some benchmarking scenarios for the searches of heavy Higgs bosons at future colliders such as the high luminosity option of the LHC and a 100 TeV hadron collider.

There is increasing evidence suggesting a discrepancy between the cosmic dipole observed in the number count of distant galaxies and the one derived from the cosmic microwave background (CMB). In this study, we investigate the possibility that the cosmic dipole problem can be addressed by considering the QCD axion, a hypothetical particle that arises from the spontaneous breaking of the Peccei-Quinn symmetry and is postulated to constitute the dark matter in our Universe.

We present a minimal grand unified theory model, based on $SU(5)$ gauge symmetry and a global $U(1)$ Peccei-Quinn symmetry, that predicts the existence of an ultralight axion dark matter within a narrow mass range of $m_a\in [0.1,4.7]\mathrm{neV}$. This mass window is determined through an interplay between gauge coupling unification constraints, partial proton decay lifetime limits, and the need to reproduce experimentally observed fermion mass spectrum. The entire parameter space of the proposed model will be probed through a synergy between several low-energy experiments that look for proton decay (Hyper-Kamiokande), axion dark matter through axion-photon coupling (ABRACADABRA and DMRadio-GUT), and nucleon electric dipole moments (CASPEr Electric).

As our recent quark model calculation [S. Noh and W. Park, Phys. Rev. D 108, 014004 (2023)] suggests a strong possibility of a compact $T_{cc}$ that closely reproduces experimental mass, we have a strong incentive to extend our work to investigate the possible compact configuration of a pentaquark $udcc\overline{s}$, which is related to the structure of the doubly charmed tetraquark $T_{cc}$. Since the introduction of a complete set of three-dimensional harmonic oscillator bases to a spatial wave function in solving a quark model-based Hamiltonian with variational method leads to a more accurate value of the mass, it seems natural that future studies of the pentaquark should be treated with the same elaborate technical approach. To attain such precision for the ground state energy, we utilize a complete set of three-dimensional harmonic oscillator base up to the sixth quanta. Before carrying out this process, one important thing that has to be taken into account is to find out the color $\otimes$ spin states of the pentaquark for the evaluation of the color and spin interaction most essential to the quark model configuration. To easily identify the suitable configuration, we make a systematic analysis of $SU(6{)}_{CS}$ irreducible representation of the pentaquark, from which we find that there is a correspondence between the color $\otimes$ spin states obtained from their coupling scheme and the multiplet of the $SU(6{)}_{CS}$ irreducible representation of the pentaquark. We find that the energy of the pentaquark configuration is $+18.5\mathrm{MeV}$ above the lowest threshold for decay into ${\mathrm{\Xi }}_{cc}$ and $K$, suggesting that this configuration is not stable against its decay. Nonetheless, while we used a Gaussian hyperfine potential, it was recently found that a Yukawa form leads to a stronger attraction for the $T_{cc}$ configuration. Therefore, it is important to study the same configuration using the latter potential.

The heavy photon search experiment (HPS) at the Thomas Jefferson National Accelerator Facility searches for electroproduced dark photons. We report results from the 2016 engineering run consisting of $10608{\mathrm{nb}}^{-1}$ of data for both the prompt and displaced vertex searches. A search for a prompt resonance in the $e^{+}{e}^{-}$ invariant mass distribution between 39 and 179 MeV showed no evidence of dark photons above the large QED background, limiting the coupling of ${\epsilon }^2\gtrsim {10}^{-5}$, in agreement with previous searches. The search for displaced vertices showed no evidence of excess signal over background in the masses between 60 and 150 MeV, but had insufficient luminosity to limit canonical heavy photon production. This is the first displaced vertex search result published by HPS. HPS has taken high-luminosity data runs in 2019 and 2021 that will explore new dark photon phase space.

We compute the supersymmetry-breaking three-form fluxes generated by the addition of anti-D3 branes at the tip of a Klebanov-Strassler throat. These fluxes give rise to nontrivial terms in the superpotential when the throat is embedded in a flux compactification. We describe these terms both from a ten-dimensional and from a four-dimensional perspective and show that, upon including Kähler-moduli stabilization, the resulting potential admits de Sitter minima. Our proposed de Sitter construction does not require additional supersymmetry-breaking (0,3) fluxes, and hence is more minimalist than the KKLT proposal.

We propose a new mechanism which simultaneously explains tiny neutrino masses, stability of dark matter and baryon asymmetry of the Universe via leptogenesis due to the common origin; a spontaneous breaking of a $U(1{)}_X$ gauge symmetry at TeV scale. The $U(1{)}_X$ breaking provides small Majorana masses of vectorlike leptons which generate small mass differences among them, and enhance their $CP$-violating decays via the resonant effect. Such $CP$-violation and lepton-number violation turns out to be a sufficient amount of the observed baryon asymmetry through leptogenesis. The Majorana masses from the $U(1{)}_X$ breaking also induce radiative generation of masses for active neutrinos at one-loop level. Furthermore, a $Z_2$ symmetry appears as a remnant of the $U(1{)}_X$ breaking, which guarantees the stability of dark matter. We construct a simple renormalizable model to realize the above mechanism, and show a benchmark point which can explain observed neutrino oscillations, dark matter data and the baryon asymmetry at the same time.

We describe an analytic procedure whereby scattering amplitudes are bootstrapped directly from an input mass spectrum and a handful of physical constraints: crossing symmetry, boundedness at high energies, and finiteness of exchanged spins. For an integer spectrum, this procedure gives a first principles derivation of a new infinite parameter generalization of the Veneziano amplitude that is unitary while exhibiting dual resonance and consistent high-energy behavior. Lifting to a $q$-deformed integer spectrum, we derive the Coon amplitude and its analogous generalizations. Finally, we apply this logic to derive an infinite class of deformed Virasoro-Shapiro amplitudes.

The complex critical points are analyzed in the four-dimensional Lorentzian Engle-Pereira-Rovelli-Livine spinfoam model in the large-$j$ regime. For the four-simplex amplitude, taking into account the complex critical point generalizes the large-$j$ asymptotics to the situation with non-Regge boundary data and relates to the twisted geometry. For generic simplicial complexes, we present a general procedure to derive the effective theory of Regge geometries from the spinfoam amplitude in the large-$j$ regime by using the complex critical points. The effective theory is analyzed in detail for the spinfoam amplitude on the double-${\mathrm{\Delta }}_3$ simplicial complex. We numerically compute the effective action and the solution of the effective equation of motion on the double-${\mathrm{\Delta }}_3$ complex. The effective theory reproduces the classical Regge gravity when the Barbero-Immirzi parameter $\gamma$ is small.

We demonstrate a relation between Nielsen’s approach toward circuit complexity and Krylov complexity through a particular construction of quantum state space geometry. We start by associating Kähler structures on the full projective Hilbert space of low rank algebras. This geometric structure of the states in the Hilbert space ensures that every unitary transformation of the associated algebras leave the metric and the symplectic forms invariant. We further associate a classical matter free Jackiw-Teitelboim gravity model with these state manifolds and show that the dilaton can be interpreted as the quantum mechanical expectation values of the symmetry generators. On the other hand, we identify the dilaton with the spread complexity over a Krylov basis thereby proposing a geometric perspective connecting two different notions of complexity.

Epicyclic frequencies are usually observed in x-ray binaries and constitute a powerful astrophysical mean to probe the strong gravitational field around a compact object. We consider them in the equatorial plane around a general stationary and axially symmetric wormhole. We first search for the wormholes’ existence, distinguishing them from a Kerr black hole. Once there will be available observational data on wormholes, we present a strategy to reconstruct the related metrics. Finally, we discuss the implications of our approach and outline possible future perspectives.

We calculate the scattering amplitude of two rotating objects with the linear-in-curvature spin-induced multipoles of Kerr black holes at $\mathcal{O}(G^2)$ and all orders in the spins of both objects. This is done including the complete set of contact terms potentially relevant to Kerr-black-hole scattering at $\mathcal{O}(G^2)$. As such, Kerr black holes should be described by this scattering amplitude for a specific choice of values for the contact-term coefficients. The inclusion of all potential contact terms means this amplitude allows for a comprehensive search for structures emerging for certain values of the coefficients, and hence special properties that might be exhibited by Kerr-black-hole scattering. Our result can also act as a template for comparison for future computations of classical gravitational high-spin scattering.

Using recently developed techniques, we consider weak-field test particle scattering angle calculations in two distinct settings: Charged test particles in spacetimes of charged sources and effective one-body theory with spin. We present scattering angle calculations up to $\mathcal{O}(G^4)$ of charged particles in the Kerr-Newman metric, including electromagnetic interactions up to second order in charge. Coulomb scattering is also discussed, and the well-known Darwin scattering formula is rederived by resummation. An effective one-body metric for a Kerr-Schwarzschild binary is constructed in a post-Minkowskian framework up to $\mathcal{O}(G^2)$ and first order in spin. Facilitated by explicit scattering calculations, our approach is equivalent with existing literature through gaugelike transformations. Finally, we investigate if the Newman-Janis algorithm applied to an effective one-body metric of nonspinning binaries represents a binary system with spin.

Tidal Love numbers describe the linear response of a compact object under the presence of external tidal perturbations, and they are found to vanish exactly for black holes within General Relativity. In this paper we investigate the tidal deformability of neutral black holes when nonlinearities in the theory are taken into account. As a case in point, we consider scalar tidal perturbations on the black hole background, and find that the tidal Love numbers may be nonvanishing depending on the scalar interactions in the bulk theory. Remarkably, for nonlinear sigma models, we find that the tidal Love numbers vanish to all orders in perturbation theory.

In this work, we investigated Bayesian methodologies for constraining in the Solar System a Yukawa suppression of the Newtonian potential—which we interpret as the effect of a non-null graviton mass—by considering its impact on planetary orbits. Complementary to the previous results obtained with INPOP (Intégrateur Numérique Planétaire de l’Observatoire de Paris) planetary ephemerides, we consider here a Markov chain Monte Carlo approach associated with a Gaussian process regression for improving the resolution of the constraints driven by planetary ephemerides on the graviton mass in the Solar System. At the end of the procedure, a posterior for the mass of the graviton is presented, providing an upper bound at $1.01\times {10}^{-24}\mathrm{eV}{c}^{-2}$ (respectively, ${\lambda }_g\ge 122.48\times {10}^{13}\mathrm{km}$) with a 99.7% confidence level. The threshold value represents an improvement of 1 order of magnitude relative to the previous estimations. This updated determination of the upper bound is mainly due to the Bayesian methodology, although the use of new planetary ephemerides (INPOP21a used here versus INPOP19a used previously) already induces a gain of a factor of 3 with respect to the previous limit. The INPOP21a ephemerides are characterized by the addition of new Juno and Mars orbiter data but also by a better Solar System modeling, with notably a more realistic model of the Kuiper belt. Finally, by testing the sensitivity of our results to the choice of the a priori distribution of the graviton mass, it turns out that the selection of a prior more favorable to zero-mass graviton (that is, here, general relativity) seems to be more supported by the observations than nonzero mass graviton, leading to a possible conclusion that planetary ephemerides are more likely to favor general relativity.

The nonlinear gravitational wave (GW) memory effect is a distinct prediction in general relativity. While the effect has been well studied for comparable mass binaries, it has mostly been overlooked for intermediate mass ratio inspirals (IMRIs). We offer a comprehensive analysis of the phenomenology and detectability of memory effects, including contributions from subdominant harmonic modes, in heavy IMRIs consisting of a stellar mass black hole and an intermediate mass black hole. When formed through hierarchical mergers, for example when a GW190521-like remnant captures a stellar mass black hole, IMRI systems have a large total mass, large spin on the primary, and possibly residual eccentricity; features that potentially raise the prospect for memory detection. We compute both the displacement and spin nonlinear GW memory from the $m\ne 0$ gravitational waveforms computed within a black hole perturbation theory framework that is partially calibrated to numerical relativity waveforms. We probe the dependence of memory effects on mass ratio, spin, and eccentricity and consider the detectability of a memory signal from IMRIs using current and future GW detectors. We find that (i) while eccentricity introduces additional features in both displacement and spin memory, it does not appreciatively change the prospects of detectability, (ii) including higher modes into the memory computation can increase signal-to-noise (SNR) values by about 7% in some cases, (iii) the SNR from displacement memory dramatically increases as the spin approaches large, positive values, and (iv) spin memory from heavy IMRIs would, however, be difficult to detect with future generation detectors even from highly spinning systems. Our results suggest that hierarchical binary black hole mergers may be a promising source for detecting memory and could favorably impact memory forecasts.

In this paper, the orbits of a charged particle near the event horizon of a magnetized black hole are investigated. For a static black hole of mass $M$ immersed in a homogeneous magnetic field $B$, the dimensionless parameter $b=eBGM/(m{c}^4)$ controls the radius of the circular orbits and determines the position of the innermost stable circular orbit (ISCO), where $m$ and $e$ are the mass and charge of the particle. For large values of the parameter $b$, the ISCO radius can be very close to the gravitational radius. We demonstrate that the properties of such orbits can be effectively and easily found by using a properly constructed “near-horizon approximation.” In particular, we show that the effective potential (which determines the position of the orbit) can be written in a form which is invariant under rescaling of the magnetic field and as a result is universal in this sense. We also demonstrate that in the near-horizon approximation, the particle orbits are stationary worldlines in Minkowski spacetime. We use this property to solve the equation describing slow changes in the distance of the particle orbit from the horizon, which arise as a result of the electromagnetic field radiated by the particle itself. This allows us to evaluate the lifetime of the particle before it reaches the ISCO and ultimately falls into the black hole.

The gravitational memory effect and its electromagnetic (EM) analog are potential probes in the strong gravity regime. In the literature, this effect is derived for static observers at asymptotic infinity. While this is a physically consistent approach, it restricts the spacetime geometries for which one can obtain the EM memory effect. To circumvent this, we evaluate the EM memory effect for comoving observers (defined by the 4-velocity $u_{\mu }$) in arbitrary curved spacetimes. Using the covariant approach, we split Maxwell’s equations into two parts—projected parallel to the 4-velocity $u_{\mu }$ and into the 3-space orthogonal to $u_{\mu }$. Further splitting the equations into $1+1+2$-form, we obtain the acceleration vector of the comoving observer located in a two-dimensional (2D) surface orthogonal to the direction of propagation of the EM waves. We refer to this expression as the master equation for the EM memory in an arbitrary curved spacetime. The master equation corresponding to the acceleration of the comoving observer in the 2D surface provides a physical understanding of the contribution to the EM memory. For instance, the leading order contribution only requires information about the total energy density of the EM field, while the subleading contributions contain information about the spacetime geometry and the other components of the energy-momentum tensor of the EM field. To our knowledge, this is the first time a transparent and easily applicable final expression for electromagnetic memory has been derived for a general curved spacetime. We then obtain EM memory for specific spacetime geometries and demonstrate the advantages of our approach.

The plunge-merger stage of the binary-black hole coalescence, when the bodies’ velocities reach a large fraction of the speed of light and the gravitational-wave luminosity peaks, provides a unique opportunity to probe gravity in the dynamical and nonlinear regime. How much do the predictions of general relativity differ from the ones in other theories of gravity for this stage of the binary evolution? To address this question, we develop a parametrized waveform model, within the effective-one-body formalism, that allows for deviations from general relativity in the plunge-merger-ringdown stage. As first step, we focus on nonprecessing-spin, quasicircular black hole binaries. In comparison to previous works, for each gravitational wave mode, our model can modify, with respect to general-relativistic predictions, the instant at which the amplitude peaks, the instantaneous frequency at this time instant, and the value of the peak amplitude. We use this waveform model to explore several questions considering both synthetic-data injections and two gravitational wave signals. In particular, we find that deviations from the peak gravitational wave amplitude and instantaneous frequency can be constrained to about 20% with GW150914. Alarmingly, we find that GW200129_65458 shows a strong violation of general relativity. We interpret this result as a false violation, either due to waveform systematics (mismodeling of spin precession) or due to data-quality issues depending on one’s interpretation of this event. This illustrates the use of parametrized waveform models as tools to investigate systematic errors in plain general relativity. The results with GW200129_65458 also vividly demonstrate the importance of waveform systematics and of glitch mitigation procedures when interpreting tests of general relativity with current gravitational wave observations.

We present analytical and numerical progress on black-hole binary spin precession at second post-Newtonian order using multitimescale methods. In addition to the commonly used effective spin which acts as a constant of motion, we exploit the weighted spin difference and show that such reparametrization cures the coordinate singularity that affected the previous formulation for the case of equal-mass binaries. The dynamics on the precession timescale is written down in closed form in both coprecessing and inertial frames. Radiation reaction can then be introduced in a quasiadiabatic fashion such that, at least for binaries on quasicircular orbits, gravitational inspirals reduce to solving a single ordinary differential equation. We provide a broad review of the resulting phenomenology and rewrite the relevant physics in terms of the newly adopted parametrization. This includes the spin-orbit resonances, the up-down instability, spin propagation at past time infinity, and new precession estimators to be used in gravitational-wave astronomy. Our findings are implemented in version 2 of the public Python module precession. Performing a precession-averaged post-Newtonian evolution from/to arbitrarily large separation takes $\lesssim 0.1\mathrm{s}$ on a single off-the-shelf processor—a $50\times$ speedup compared to our previous implementation. This allows for a wide variety of applications including propagating gravitational-wave posterior samples as well as population-synthesis predictions of astrophysical nature.