Extracting parton structure from lattice quantum chromodynamics (QCD) calculations requires studying the coordinate scale $z_3$ dependence of the matrix elements of bilocal operators. The most significant contribution comes from the $z_3$ dependence induced by ultraviolet (UV) renormalization of the Wilson line. We demonstrate that the next-to-leading order perturbative calculations of the renormalization factor can describe, to a few percent accuracy, the logarithm of the lattice QCD rest frame matrix elements with separations up to distances of 0.6 fm on multiple lattice spacings. The residual discrepancies can be modeled by a leading effect from the structure of the nucleon.

We use a simple holographic model to discuss approaching the edge of the conformal window in strongly coupled gauge theories to draw lessons for lattice studies. Walking gauge theories have a gap between the scale where they enter the strong coupling regime and the scale of chiral symmetry breaking. We highlight that there can also be a gap between the scale where the critical value of the quark-antiquark operator’s anomalous dimension is passed and the scale of the condensate. This potentially makes identifying the edge of the conformal window in a lattice simulation with UV bare coupling below the fixed point value on a finite lattice difficult. A resolution is to study the theory with a coupling above the fixed point value at the UV cutoff. Here we show that an “artifact” phase with chiral symmetry breaking triggered at the UV cutoff exists and lies arbitrarily close to the fixed point at the edge of the conformal window. We quantify the chance of a misidentification of a chiral-symmetry-breaking theory as IR conformal. We also quantify where the artifact phase lies, tuned to the fixed point value. We use the latest lattice results for SU(3) gauge theory with ten quark flavors in [, Phys. Rev. D 108, L071503 (2023)] as a test case; we conclude that their identification of the theory being in the conformal window is reliable.

Using a three-flavor Nambu–Jona-Lasinio model to describe the charge-parity violating effects through axion field, we investigate the axion effects on quark matter and quark-matter cores in massive hybrid stars. Within the range from 0 to $\pi$, the axion field $a/f_a$ decreases the baryon chemical potential of the first-order phase transition, leading to an increase in normalized pressure and stiffening of the quark matter equation of state. The effect of axions on hybrid star matter that includes the hadron-quark phase transition is contrary to expectations. The axion field shifts the onset of the hadron-quark mixed phase to lower densities but slightly softens the equation of state of the mixed phase matter, which also results in a slight decrease in the maximum mass and corresponding radius of the hybrid stars. However, we also find that the lowering of the onset of the mixed phase significantly increases the radius and mass of the quark-matter core in the hybrid star. Therefore, our results indicate that with axion effects, a sizable quark-matter core can appear in $2M_{\odot }$ massive neutron stars.

The possibility of compact stars as hideouts for color-spin-locked (CSL) quark matter (QM) is investigated in both the MIT bag model and the Nambu-Jona-Lasinio (NJL) model. Within the framework of the NJL model, the idea of absolutely stable quark matter and the existence of the conventional pure quark star (QS) are not supported; in addition, there appears to be no stable hybrid configuration above $2M_{\odot }$ as the hideout for CSL QM. The stable configurations of massive strange quark stars could be reproduced in the MIT bag model with QCD corrections being taken into account; moreover, they could act as the hiding place for the CSL QM. An interesting scenario is proposed that the phase transition to the CSL phase could occur in the cooling process. The CSL quark matter is an electromagnetic (EM) superconductor of type I, and a complete Meissner effect is expected. However, the analysis for this sizable superconductor indicates that most of the magnetic field is frozen inside the quark core with a critical strength, while in some special cases a small fraction could be expelled from a thin layer near the surface in a short time. The analysis on energetics and timescale suggests that this process could act as an inducement mechanism to power typical fast radio bursts, but as a single source of energy, it is unlikely to generate other EM emissions such as gamma-ray bursts and giant flares.

We study electromagnetic radiation by electrically charged fermions embedded in a rotating medium in an external magnetic field. We compute the dependence of the radiation intensity on the angular velocity $\mathrm{\Omega }$ of the rotating medium for fermion polarizations along and opposite the magnetic field direction in intense subcritical fields. The polarization dependence of the photon radiation results in the Sokolov-Ternov effect—the radiative polarization of fermions. We study the dependence of the degree of polarziation on $\mathrm{\Omega }$. We found that rotation significantly changes the degree of polarization. We show that the rotating quark-gluon plasma acquires a finite magnetic moment that exhibits complex dependence on $\mathrm{\Omega }$.

Light thermal dark matter has emerged as an attractive theoretical possibility and a promising target for discovery at experiments in the near future. Such scenarios generically invoke mediators with very small couplings to the Standard Model, but with moderately strong couplings within the dark sector, calling into question theoretical estimates based on the lowest order of perturbation theory. As an example, we focus on a scenario in which (pseudo-)Dirac fermion dark matter is connected to the Standard Model via a dark photon charged under a new $U(1{)}^{\prime }$ extension of the standard model, and we investigate the impact of the next-to-leading order corrections to annihilation and scattering. We find that radiative corrections can significantly impact model predictions for the relic density and scattering cross section, depending on the strength of the dark sector coupling and ratio of the dark matter to mediator mass. We also show why factorization into the yield parameter $Y$ typically presented in literature leads to imprecision. Our results are necessary to accurately map experimental searches into the model parameter space and assess their ability to reach thermal production targets.

Wash-in leptogenesis is an attractive mechanism to produce the baryon asymmetry of the Universe. It treats right-handed-neutrino interactions as spectator processes, on the same footing as electroweak sphalerons, that reprocess primordial charge asymmetries in the thermal plasma into a baryon-minus-lepton asymmetry. The origin of these primordial charges must be accounted for by new $CP$-violating dynamics at very high energies. In this paper, we propose such a scenario of chargegenesis that, unlike earlier proposals, primarily relies on new interactions in the gravitational sector. We point out that a coupling of a conserved current to the divergence of the Ricci scalar during reheating can lead to nonzero effective chemical potentials in the plasma that, together with a suitable charge-violating interaction, can result in the production of a primordial charge asymmetry. Gravitational chargegenesis represents a substantial generalization of the idea of gravitational baryogenesis. We provide a detailed analysis of a generic and minimal realization that is consistent with inflation and show that it can successfully explain the baryon asymmetry of the Universe.

Multi-Higgs boson interactions with massive gauge bosons are known to be tell-tale probes of the vacuum manifold of electroweak symmetry breaking. Phenomenologically, a precise determination of these parameters is hampered through increasingly rare processes at the presently available energy frontier provided by the Large Hadron Collider. Contact interactions of three Higgs bosons with the $W$ and $Z$ bosons seem currently well out of experimental reach due to an irrelevant standard model (SM) production cross section. From a theoretical perspective, in perturbative extensions of the SM such interactions are suppressed by weak loops and further diluted in a priori sensitive processes like weak boson fusion (WBF) when they admit a dimension-six Standard Model effective field theory description. In this work, we identify scenarios that can indeed lead to large, and perhaps even observable modifications of WBF triple Higgs production most directly parametrized by Higgs effective field theory. We critically analyse these enhancements at the LHC and future colliders from the perspective of unitarity and demonstrate the radiative stability of such analyses under QCD corrections at hadron colliders. Taking into account the restrictions from unitarity, we finally study the expected sensitivity to the electroweak triple Higgs production within HEFT, considering $HHVV$ and $HHHVV$ effective couplings, at both future hadron and lepton colliders. Particularly, we present numerical predictions for LHC, FCC, CLIC, and muon colliders.

The observation of the coherent elastic neutrino-nucleus scattering process using reactor antineutrinos offers a unique opportunity to probe the Standard Model and explore beyond the Standard Model scenarios. This study reports on the latest results from the $\mathrm{CONUS}+\text{experiment}$ conducted at the Leibstadt nuclear power plant in Switzerland. The CONUS collaboration reports $395\pm 106$ events detected from reactor antineutrinos with an exposure of $327\mathrm{kg}·\mathrm{days}$, utilizing high-purity germanium detectors operated at sub-keV thresholds. A ${\chi }^2$-based statistical analysis was performed on these results, incorporating systematic uncertainties. This analysis was used to extract the weak mixing angle, establish a limit on the neutrino magnetic moment, and impose constraints on neutrino nonstandard interactions using reactor antineutrinos. The results confirm the potential of coherent elastic neutrino-nucleus scattering experiments in the study of fundamental neutrino properties and probing new physics.

We investigate the astrophysical consequences of an attractive long-range interaction between dark matter and baryonic matter. Our study highlights the role of this interaction in inducing dynamical friction between dark matter and stars, which can significantly influence the evolution of compact stellar systems. Using the star cluster in Eridanus II as a case study, we derive a new stringent upper bound on the interaction strength $\tilde{\alpha }\le 314.5$ for the interaction range $\lambda =1\mathrm{pc}$. This constraint is independent of the dark matter mass and can improve the existing model-independent limits on $\tilde{\alpha }$ by a few orders of magnitude. Furthermore, we observe that the constraint is insensitive to the mass of the stellar system and the dark matter density in the stellar system as long as the system is dark matter dominated. This new approach can be applied to many other stellar systems, and we obtain comparable constraints from compact stellar halos observed in ultrafaint dwarf galaxies.

According to the microscopic formulation of Landauer’s principle, when information is deleted, the von Neumann entropy of the system gets reduced with a corresponding energy cost. Although within the same perspective the growth of the entropy should remain unconstrained, we show that during quantum amplification the heat flow does restrict the increase of the von Neumann entropy. When applied to the case of relic gravitons (with frequencies between the aHz region and the THz domain), the bounds obtained here set a limit on initial thermal gravitons and on the total duration of inflation.

Maximal supergravities in ten and eleven dimensions admit consistent truncations on particular spheres to maximal supergravities in lower dimensions. Concurrently, the truncation to singlets under any subgroup of the sphere isometry group leads to consistent truncations with less or no supersymmetry. We review the relation between these truncations in the framework of exceptional field theory. As an application, we derive three new ${\mathrm{G}}_2$-invariant solutions of $D=11$ supergravity. Their geometry is of the form ${\mathrm{AdS}}_4\times {\mathrm{\Sigma }}_7$ where ${\mathrm{\Sigma }}_7$ is a deformed seven-sphere, preserving SO(7) isometries.

We present two new frequency-domain gravitational waveform models for the analysis of signals emitted by binary neutron star coalescences: IMRPhenomXAS_NRTidalv2 and IMRPhenomXP_NRTidalv2. Both models are available through the public algorithm library lalsuite and represent the first extensions of IMRPhenomX models including matter effects. We show here that these two models represent a significant advancement in efficiency and accuracy with respect to their phenomenological predecessors, IMRPhenomD_NRTidalv2 and IMRPhenomPv2_NRTidalv2. The computational efficiency of the new models is achieved through the application of the same multibanding technique previously applied to binary black hole models. Furthermore, IMRPhenomXP_NRTidalv2 implements a more accurate description of the precession dynamics, including double-spin effects and, optionally, matter effects in the twisting-up construction. The latter are available through an option to use a numerical integration of the post-Newtonian precession equations. We show that the new precession descriptions allow the model to better reproduce the phenomenology observed in numerical-relativity simulations of precessing binary neutron stars. Finally, we present some applications of the new models to Bayesian parameter estimation studies, including a reanalysis of GW170817 and a study of simulated observations using numerical relativity waveforms for nonprecessing binary neutron stars with highly spinning components. We find that in these cases the new models make a negligible difference in the results. Nevertheless, by virtue of the aforementioned improvements, the new models represent valuable tools for the study of future detections of coalescing binary neutron stars.

We revisit the conformally coupled scalar gravitational theory. This is the simplest local-scale invariant theory of gravity which is linear in the curvature scalar. We demonstrate that, if local-scale symmetry is properly taken into account in the variational procedure, it is not required that the trace of the stress-energy tensor of the matter fields vanished for this symmetry be preserved. The relevance of this result for the understanding of local-scale symmetry along with its physical consequences, is discussed.

Black hole (BH)-neutron star (NS) binary mergers are not only strong sources of gravitational waves (GWs), but they are also candidates for joint detections in the GW and electromagnetic (EM) spectra. However, the possible emergence of an EM signal from these binaries relies crucially on the fate of the NS which, in turn, is determined by a complex combination of the equation of state (EOS), the BH spin, and the mass ratio. Depending on these binary parameters, the NS can either undergo a “tidal disruption” or “plunge” directly into the BH without losing its compact structure beforehand. Accurate predictions as to which of these scenarios actually takes place relies on the use of numerical-relativity simulations, which represent essential tools to learn about the properties of the system. In this second paper in a series, we present a systematic exploration of the possible space of binary parameters in terms of the mass ratio and BH spin so as to construct a complete description of the dynamical processes accompanying a BHNS binary merger. This second work relies not only on the initial data of eight nonprecessing spinning binaries presented in the companion paper I, but also on the predictions via quasiequilibrium (QE) sequences on the outcome of the binary. In this way, and for the first time, we are able to relate the predictions of QE analyses with the results of accurate general-relativistic magnetohydrodynamic simulations. In addition to a careful investigation of the evolution of the BH mass and spin as a result of the merger, the total remnant rest-mass of the resulting accretion disk and its properties, and of the corresponding postmerger GW emission, special attention is paid to the conditions that lead to tidal disruption. Leveraging QE calculations, we are able to verify the reliability of stringent predictions about the occurrence or not of a plunge and to measure the “strength” of the tidal disruption when it takes place. Finally, using a novel contraction of the Riemann tensor in a locally orthonormal tetrad and with respect to the one comoving with the fluid introduced in paper I, we are able to point out the onset of the instability to tidal disruption. This new diagnostic can be employed not only to determine the occurrence of the disruption, but also to characterize it in terms of the binary parameters.

Black hole-neutron star (BHNS) mergers are a promising target of current gravitational-wave (GW) and electromagnetic (EM) searches, being the putative origin of ultrarelativistic jets, gamma-ray emission, and r-process nucleosynthesis. However, the possibility of any EM emission accompanying a GW detection crucially depends on the amount of baryonic mass left after the coalescence, i.e., whether the neutron star (NS) undergoes a “tidal disruption” or “plunges” into the black hole (BH) while remaining essentially intact. As the first of a series of two papers, we here report the most systematic investigation to date of quasiequilibrium sequences of nonprecessing initial data across a range of stellar compactnesses $\mathcal{C}$, mass ratios $q$, BH spins ${\chi }_{\mathrm{BH}}$, and equations of state satisfying all present observational constraints. Using an improved version of the elliptic initial-data solver fuka, we have computed more than 1000 individual configurations and estimated the onset of mass-shedding or the crossing of the innermost stable circular orbit in terms of the corresponding characteristic orbital angular velocities ${\mathrm{\Omega }}_{\mathrm{MS}}$ and ${\mathrm{\Omega }}_{\mathrm{ISCO}}$ as a function of $\mathcal{C}$, $q$, and ${\chi }_{\mathrm{BH}}$. To the best of our knowledge, this is the first time that the dependence of these frequencies on the BH spin is investigated. In turn, by setting ${\mathrm{\Omega }}_{\mathrm{MS}}={\mathrm{\Omega }}_{\mathrm{ISCO}}$ it is possible to determine the separatrix between the tidal disruption or plunge scenarios as a function of the fundamental parameters of these systems, namely, $q$, $\mathcal{C}$, and ${\chi }_{\mathrm{BH}}$. Finally, we present a novel analysis of quantities related to the tidal forces in the initial data and discuss their dependence on spin and separation.

Wormholes are exotic compact objects characterized by the absence of essential singularities and horizons, acting as slender bridges linking two distinct regions of spacetime. Despite their theoretical significance, they remain, however, undetected, possibly due to their ability to closely mimic the observational properties of black holes. This study explores whether a static and spherically symmetric wormhole within General Relativity can reproduce the quasinormal mode spectrum of a Schwarzschild black hole under scalar, electromagnetic, and axial gravitational perturbations, both individually and in combination. To address this, we reformulate the wormhole metric components using a near-throat parametrization. Our analysis concentrates on the fundamental mode and first overtone, estimated via the Wentzel-Kramers-Brillouin method. By employing a customized minimization strategy, we demonstrate that, within a specific region of the parameter space, a wormhole can successfully replicate a subset of the black hole quasinormal mode spectrum.

We introduce a large family of homogeneous and isotropic cosmological solutions in quadratic gravity which are singularity-free at early and late times. This kind of smooth solutions only emerge beyond the nonstandard de Sitter branch $3\alpha <\beta$, $\alpha$ and $\beta$ being the couplings of the $R^2$ and $-R_{\mu \nu }^2$ terms. We have analyzed the stability of these singularity-free solutions by computing the second-order variation of the action. We show that the expected instability is similar to that of the standard $\mathrm{\Lambda }$ Cold Dark Matter ($\mathrm{\Lambda }$ CDM) scenario. Thus, they provide cosmological background scenarios as legitimate as that of the Standard Model. The complete analysis shows that a singular big bang scenario can emerge from a singularity-free cosmological scenario when the parameters of the theory are slightly modified, which provides a bridge between the two very different cosmological scenarios with similar instabilities.

There exist two consistent theories of self-interacting gravitons: general relativity and Weyl transverse gravity. The latter has the same classical solutions as general relativity but different local symmetries. We argue that Weyl transverse gravity also naturally arises from thermodynamic arguments. In particular, we show that thermodynamic equilibrium of local causal diamonds together with the strong equivalence principle encodes the gravitational dynamics of Weyl transverse gravity rather than general relativity. We obtain this result in a self-consistent way, verifying the validity of our initial assumptions, i.e., the proportionality between entropy and area and the different versions of the equivalence principle in Weyl transverse gravity. Furthermore, we extend the thermodynamic derivation of the equations of motion from Weyl transverse gravity to a class of modified theories of gravity with the same local symmetries. For this purpose, we employ the general expression for Wald entropy in such theories.