Gravitational redshift imprints a slight asymmetry in the observed clustering of galaxies, producing odd multipoles (e.g., the dipole) in the cross-correlation function. But there are other sources of asymmetry which must also be considered in any model which aims to measure gravitational redshift from large-scale structure. In this work we develop a nonlinear model of the redshift-space correlation function complete down to these subleading, asymmetric effects. In addition to gravitational redshift and the well-known redshift-space distortions, our model, given by a compact nonperturbative formula, also accounts for wide-angle effects (to all orders), light cone effects, and other kinematic contributions. We compare our model with $N$-body simulations and find good agreement; in particular we find that the observed turnover in the dipole moment around a separation of $20h^{-1}\mathrm{Mpc}$ (a feature absent in the linear predictions) is accounted for well. By examining the exchange properties of distinct tracers, we identify the pairwise potential difference as the key physical ingredient of the dipole. Several new insights related to the theory of redshift-space distortions are also given.

Gravitational waves (GWs) exhibit wave-optics effects when their wavelength is comparable to the scale of the gravitational lens. This may occur in lensing from galactic subhalos in GWs emitted by binary black-hole mergers and is gaining interest as a novel probe of dark matter. Predictions for observables in these cases ultimately rely on evaluating a Fresnel integral that quantifies the effect of lensing on the amplitude of a GW at a given frequency. However, numerical evaluation of this Fresnel integral is tricky, and several algorithms and publicly available codes that implement it have been developed. Here, we show that the dependence of this integral on the lens position can be written as a two-dimensional Fourier transform. Modern FFT techniques then enable rapid evaluation at all-sky positions simultaneously for general lenses without symmetry. Vectorization of FFT routines allows for derivatives with respect to model parameters to be obtained with only incremental additional computational cost. If the lens is axisymmetric, further speedups can be achieved with recently developed techniques for nonuniform fast Hankel transforms. To demonstrate, we make available Fresnel Integral Optimization with Nonuniform Transforms (fiona), an efficient and accurate code that is significantly faster than current methods for dense source grids, reaching 2 orders of magnitude speedups for $\sim {10}^6$ GW-emitting points. As part of fiona, we developed code that provides vectorized nonuniform fast Hankel transforms that may have other uses (e.g., calculation of cosmological two-point correlation functions) beyond those considered here.

We present the first detection of weak gravitational lensing around spectroscopically confirmed dwarf galaxies, using the large overlap between DESI DR1 spectroscopic data and DECADE/DES weak lensing catalogs. A clean dwarf galaxy sample with well-defined redshift and stellar mass cuts enables excess surface mass density measurements in two stellar mass bins ($\log {\mathrm{M}}_{*}=[8.2,9.2]M_{\odot }$ and $\log {\mathrm{M}}_{*}=[9.2,10.2]M_{\odot }$), with signal-to-noise ratios of 5.6 and 12.4 respectively. This signal-to-noise drops to 4.5 and 9.2 respectively for measurements without applying individual inverse probability (IIP) weights, which mitigates fiber incompleteness from DESI’s targeting. The measurements are robust against variations in stellar mass estimates, photometric shredding, and lensing calibration systematics. Using a simulation-based modeling framework with stellar mass function priors, we constrain the stellar mass-halo mass relation and find a satellite fraction of $\simeq 0.3$, which is higher than previous photometric studies and somewhat lower than the value predicted by the same $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$)-based forward model given the inferred stellar mass-halo mass relation. We find that IIP weights have a significant impact on lensing measurements and can change the inferred $f_{\mathrm{sat}}$ by a factor of two, highlighting the need for accurate fiber incompleteness corrections for dwarf galaxy samples. Our results open a new observational window into the galaxy-halo connection at low masses, showing that future massively multiplexed spectroscopic observations and weak lensing data will enable stringent tests of galaxy formation models and $\mathrm{\Lambda }\mathrm{CDM}$ predictions.

Dark matter is expected to accumulate inside neutron stars, modifying the structure of isolated stars and influencing both the dynamics of binary mergers and the evolution of the resulting hypermassive remnants. Since differential rotation is the primary mechanism delaying the collapse of these remnants, understanding its behavior is crucial when assessing the impact of an embedded dark component. In this work, we extend the numerical code rns to describe two gravitationally coupled fluids in differential rotation, with baryonic matter modeled by a realistic nuclear equation of state and dark matter represented as a self-interacting bosonic condensate. Restricting the models to the zero-temperature approximation, we focus on the internal equilibrium structure. Within this framework, we construct equilibrium sequences for a representative differential rotation law, providing a basis to explore how dark matter may influence the global properties and rotational dynamics of binary neutron star remnants.

Dark matter direct detection experiments involving electron recoils are beginning to test highly predictive, thermal-relic milestones for sub-GeV dark matter models. Due to the Lee-Weinberg bound, thermal dark matter candidates in this mass range necessarily require comparably light mediator particles to achieve a suitably large annihilation cross section. Here we present new thermal-relic milestones for sub-GeV dark matter candidates that couple to vector mediators. In these models, the mediators are massive gauge bosons of anomaly-free Abelian extensions to the Standard Model, including the dark photon, gauged $L_i-L_j,B-L$, and $B-3L_i$ models, where $B$ is the baryon number, $L$ is the lepton number, and $i$, $j$ index the lepton families. Since the same interactions that govern cosmological production also govern electron scattering, the targets we present are firmly predictive and allow for these models to be robustly discovered or falsified. Furthermore, since the mediators we study exhaust the minimal anomaly-free U(1) extensions to the Standard Model, our results offer a complete list of predictive milestones for sub-GeV dark matter coupled to vector mediators.

The phase space of hadron collider events spans hundreds of dimensions, generating an intricate geometry that we are just starting to explore. The number of possible new physics signals is exponential in the number of dimensions and detecting all of them is currently impossible for any human or artificial intelligence. In this work we introduce a method to search for new physics model independently in this high-dimensional space. It is based on the measurement of the most basic property of the manifold of collider events, its dimensionality. Our proposed technique does not suffer from a look-elsewhere effect that grows exponentially with the number of dimensions of the dataset, and by construction is insensitive to energy scale uncertainties. We illustrate its potential by finding new physics in simulated events with hundreds of phase space dimensions, taking as input single particles rather than jets. This study sets the stage for new model-independent search strategies based on global properties of collider data manifolds.

Within the nonrelativistic QCD framework, we investigate the associated production of charmonia and bottomonia at the future super $Z$-factory and at CEPC and FCC-ee. The color-octet (CO) channels in the ${\gamma }^{*}/Z^0$-propagated processes are considered in addition to the color-singlet (CS) channels. We find that the contributions from the CO channels are substantial or even dominant for nearly all processes from the production threshold to the $Z^0$ pole region. However, estimates of the production rate are highly sensitive to long-distance matrix elements (LDMEs) selections, so different combinations of LDMEs produce markedly different production yields. For this reason, the study of charmonia-bottomonia production at the future super $Z$-factory can serve as a viable probe of the CO mechanism, and the comparison between the theoretical results and future experimental data may provide constraints on the CO matrix elements. In addition, we calculate the relativistic corrections to both the CS and CO channels, which decrease the cross sections significantly, yielding a $K$ factor of approximately 0.5. The predicted event yields of ($J/\psi +\mathrm{\Upsilon },\mathrm{\Upsilon }+{\eta }_c$) production, with $J/\psi ,\mathrm{\Upsilon }$ reconstructed via lepton pairs and ${\eta }_c$ reconstructed via hadronic decays, are (2, 4) and (18, 35) at the CEPC (2-year) and FCC-ee (4-year), respectively.

In this paper, we have studied the impact of two different formalisms of quantum decoherence in determining the sensitivities of the two future long-baseline experiments DUNE and P2SO. In formalism A, we will assume that the decoherence matrix is defined in a matter mass eigenstate basis which is the basis that diagonalizes the Hamiltonian for neutrinos in matter, with a constant matter density. In formalism B, we will define the decoherence matrix in the vacuum mass eigenstate basis and then rotate it to matter mass basis via an unitary transformation. By using different values of the decoherence parameter $\mathrm{\Gamma }$, we will show how these two formalisms differ at the probability level and then we will demonstrate how the sensitivities can differ at the ${\chi }^2$ level. Our results show that if the values of $\mathrm{\Gamma }$ are small, then these two formalisms yield same probability in vacuum. However, if the values of $\mathrm{\Gamma }$ is large or if there is strong matter effect, then these two formalisms yield very different results.

Observation of baryon number violation (BNV) in laboratory experiments would constitute unambiguous evidence for physics beyond the Standard Model. We propose dedicated searches for apparent BNV in charm-baryon decays, ${\mathrm{\Lambda }}_c^{+}\to M^{+}+$ missing energy ($M=\pi ,K$), where the missing energy stems from a resonance. These channels have not been explored experimentally so far, despite the relatively clean environment potentially provided by near-${\mathrm{\Lambda }}_c^{+}{\overline{\mathrm{\Lambda }}}_c^{-}$ threshold production at $e^{+}{e}^{-}$ colliders. Performing state-of-the-art Monte Carlo simulations for the proposed Super Tau-Charm Facility (STCF), we evaluate the signal efficiencies and derive projected model-independent sensitivities under the assumption of negligible background. We further interpret these sensitivities within two theoretical frameworks: a sterile-neutrino-extended low-energy effective field theory ($\nu \mathrm{LEFT}$) and R-parity-violating (RPV) supersymmetry. With an integrated luminosity of $1{\mathrm{ab}}^{-1}$, STCF can probe new-physics scales of several TeV in the $\nu \mathrm{LEFT}$ description and constrain the RPV model parameter ${\lambda }_{212}^{\prime \prime }/m_{\tilde{q}}^2$ down to about $0.1{\mathrm{TeV}}^{-2}$. Our results demonstrate that STCF provides a highly competitive opportunity for probing BNV interactions in rare charm-baryon decays.

The cosmological evolution of a scalar field is shaped by Hubble damping. Any nongravitational couplings of the scalar with the primordial thermal bath generically contribute additional damping. Although often neglected, such thermal damping could be the dominant dissipative effect on the scalar. We derive approximate yet highly general thermal damping rates of scalar fields that modulate the masses of thermally populated particles. We extend previous results to cover cases of particular phenomenological interest where the scalar background oscillates sinusoidally but not necessarily slowly compared to the thermalization rates of the primordial bath. As applications, we estimate the thermal damping of scalars coupled linearly to neutrinos, quadratically to gluons, and linearly to Weakly Interacting Massive Particles, and demonstrate the importance of this effect in certain parameter spaces of these models. We also estimate the thermal damping rates in models of QCD axions.

Standard calculations of cosmological first-order phase transitions usually assume critical bubbles to nucleate on a homogeneous symmetric vacuum background. However, this assumption can fail in weak transitions, where thermal fluctuations trigger subcritical bubbles before the standard nucleation temperature $T_n$. Motivated by this possibility, we systematically examine whether the homogeneous nucleation background approximation is self-consistent. By evolving the Gelmini-Gleiser subcritical bubble kinetics and comparing it with the standard critical bubble nucleation picture, we identify the parameter regions in which the background becomes apparently mixed. A detailed scan of these regions shows that sizable subcritical volume fractions arise when the two phases are nearly degenerate at $T_n$, the potential barrier is low, the difference of free energy between the symmetric and broken phases is moderate and the transition strength is weak. Within this simplified phenomenological kinetic framework, this scan further calibrates a practical reference criterion, ${\log }_{10}{\widehat{f}}_{\xi }(T_n)\simeq -1.95$, for percent level subcritical bubble volume fractions. Parameter points above this boundary should be treated as mixed background candidates rather than as ordinary homogeneous bounce points.

We calculate the gluon momentum fraction of the nucleon using lattice QCD, with a nonperturbative renormalization technique based on the gradient flow. The gluon momentum fraction is determined on a single Wilson-clover ensemble using $N_f=2+1$ flavors with pion mass 358 MeV and lattice spacing 0.094 fm. We employ the variational method to reduce excited-state contamination and apply the distillation framework to ensure a large operator basis. To reduce systematic uncertainties, we apply Bayesian model averaging to all fit procedures. We apply matching coefficients to the flow-time dependent lattice results to recover the gluon momentum fraction in the $\overline{\mathrm{MS}}$-scheme at 2 GeV. Our final result is $⟨x{⟩}_g(\mu =2\mathrm{GeV})=0.482(35)$, where we quote only statistical uncertainties.

Strongly coupled theories are of phenomenological interest, for example as dark matter candidates. Theories that can undergo first-order thermal phase transitions are particularly appealing as potential sources of a stochastic gravitational wave background. Determining the expected gravitational wave signal from a first-order phase transition requires accurate information on the bubble nucleation rate, but thus far for strongly coupled models these have relied on semiclassical methods. As a first step toward determining the nucleation rate, in this paper we study the confinement-deconfinement phase transition in a 4D SU(8) pure gauge model, using multicanonical Monte Carlo. Resolving the critical bubble for the first time in a pure Yang-Mills model, we determine the critical bubble probability and compare it to results from thin wall calculations. We also compare the effectiveness of different lattice pseudo-order parameters at resolving the condensation transition between the metastable phase and critical bubble branch, and point out that the choice of order parameter is crucial to accurately resolve the critical configurations.

A systematic way to constructing optimized interpolating operators for two-hadron systems is developed by incorporating interhadron spatial wave functions. The wave functions can be obtained from an iterative process with an appropriate initial guess. To implement these operators, a novel quark smearing technique utilizing $Z_3$ noise vectors is proposed, which allows for effectively incorporating interhadron spatial wave functions at the source without using all-to-all quark propagators. Proof-of-principle application to the ${\mathrm{\Omega }}_{ccc}{\mathrm{\Omega }}_{ccc}$ system using physical-point lattice configurations with a large size $La\simeq 8.1\mathrm{fm}$ demonstrates that optimized operators outperform combinations of limited plane wave operators in the variational analysis, enabling clear identification of states around $2m_{{\mathrm{\Omega }}_{ccc}}\simeq 9700\mathrm{MeV}$ with the energy gap as narrow as $\sim 5\mathrm{MeV}$. A comparison on correlation functions, effective energies, and HAL QCD potentials between unoptimized operators and optimized operators is given, with a special emphasis on the effects from nearby elastic scattering states. Potential applicability of the optimized operator to various two-hadron systems and its relation to the variational method are also discussed.

We investigate the existence of the three-body molecular state composed of $D{D}^{*}{\overline{K}}^{*}$ within the one-boson-exchange model. A major challenge is that while the pseudoscalar-meson couplings are well determined, the couplings for scalar- and vector-meson exchanges render significant model dependence. To ensure the reliability of our predictions and reduce model dependence, we recalibrate the coupling constants of the one-boson-exchange model. We treat the pole position of $Z_c(3900)$, or equivalently the scalar $\sigma$-exchange coupling constant, as the only unknown parameter. The coupling constants for the vector $\rho$ and $\omega$ exchanges are determined by the pole positions of the well-established states $X(3872)$ and $T_{cc}(3875)$. We demonstrate that these parameter sets also successfully describe the $T_{cs0}(2870)$ without further tuning. For the three-body system, our results indicate that an $I(J^P)=1/2(0^{-})$ three-body molecular bound state exists when $Z_c(3900)$ is a virtual state located within approximately $-10\mathrm{MeV}$ of the $D{\overline{D}}^{*}$ threshold. Furthermore, we extend our analysis to the complex energy plane using the complex scaling method to search for molecular resonances, though no evidence of resonances is found in considered channels. We also apply this formalism to the bottom analog $B{B}^{*}{K}^{*}$ system. In this sector, the conditions for the existence of a three-body bound state are more relaxed, as a $Z_c(3900)$ virtual state located within $-25\mathrm{MeV}$ below the threshold suffices, although three-body molecular resonances remain absent. We suggest that future experiments precisely measure the pole position of $Z_c(3900)$ or search for the three-body bound state in $DD\overline{K}\pi \pi$ and $DD\overline{K}$ channels, as these efforts would mutually illuminate the nature of the associated states.

We investigate the strong decay $J/\psi \to {\rho }^{+}{\rho }^{-}\omega$ and the radiative decay $J/\psi \to \gamma {\rho }^0\omega$, taking into account the $S$-wave $K^{*}{\overline{K}}^{*}$, $\rho \omega$ and $\rho \varphi$ final-state interactions, which dynamically generate the scalar meson $a_0(1710)$. Our results demonstrate that a clear peak structure emerges around 1.8 GeV in the ${\rho }^{+}\omega$ (${\rho }^{-}\omega$) invariant mass distribution of the strong decay, which can be associated with the $a_0(1710)$ resonance. Similarly, a distinct peak is predicted in the ${\rho }^0\omega$ invariant mass distribution of the radiative decay. Our results indicate that clear signals of $a_0(1710)$ production could be observed in future measurements of these processes at BESIII, Belle II, and the planned Super Tau-Charm Facility, thereby helping to determine its mass and width more precisely.

We present the first fully off-shell covariant investigation of the $S=-1$ meson-baryon interaction within the unitarized chiral effective field theory framework up to next-to-leading order. In particular, we perform a detailed comparison with the widely used on-shell approximation. We find that the resulting scattering observables are very similar, thereby confirming the validity of key results obtained within the on-shell scheme. A notable advantage of the off-shell treatment, however, is the absence of unphysical left-hand cuts induced by the on-shell approximation. Employing the off-shell amplitudes, we compute the femtoscopic correlation functions for $K^{-}p$ and ${\pi }^{\pm }{\mathrm{\Sigma }}^{\mp }$ pairs. The $K^{-}p$ correlation functions are found to be consistent with previously published results based on the on-shell approximation, with marginal differences arising from slightly different descriptions of scattering data. The ${\pi }^{\pm }{\mathrm{\Sigma }}^{\mp }$ correlation functions are predicted for the first time and are expected to provide valuable constraints on the nature of the $\mathrm{\Lambda }(1405)$ resonance and the coupled-channel chiral dynamics of the $\overline{K}N-\pi \mathrm{\Sigma }$ system.

Probing gravity in its strongest regime is a central goal of modern physics, as the nature of the most compact objects reflects fundamental aspects of Einstein’s theory of general relativity (GR). In GR, black holes are regarded as the most compact objects in the Universe. Here, for the first time, we demonstrate that stable stellar configurations more compact than black holes can arise when neutron-star equations of state are embedded in quasitopological gravity, a class of higher-curvature extensions of GR. We construct such ultracompact stars, analyze their macroscopic properties, and establish their stability against radial perturbations, confirming their physical plausibility. We further identify potential observational signatures to distinguish these stars from black holes, most notably gravitational-wave echoes whose detectability could provide direct evidence of physics beyond Einstein’s GR in the strong-field regime.

We investigate axion production in the collision between a spin-polarized relativistic electron beam and an ultraintense laser pulse. A spin-resolved Monte Carlo framework is developed to model axion-electron and axion-photon couplings in arbitrary electromagnetic fields, using quantum emission probabilities under the local constant field approximation. Owing to spin-dependent asymmetries in the radiation probability, the emitted axions acquire a characteristic angular deflection correlated with the initial electron polarization, enabling control of the axion emission via the polarizations of the electron beam and laser field. Simulations demonstrate that a dense ($\sim {10}^{10}{g}_{ae}^2$) and highly collimated axion beam with a tunable milliradian-scale deflection can be produced within tens of femtoseconds using current laser technology. The polarization-tagged angular asymmetry, combined with femtosecond time gating, provides enhanced signal-background discrimination. These results establish a spin-dependent mechanism for manipulating axion trajectories and open a promising route toward laboratory-based searches for the axion-electron coupling.

A systematic framework for constructing optimized interpolating operators strongly coupled to QCD two-particle states is developed, which is achieved by incorporating interhadron spatial wave functions. To efficiently implement these operators in lattice QCD, a novel quark smearing technique utilizing noise vectors is proposed. Applied to the ${\mathrm{\Omega }}_{ccc}{\mathrm{\Omega }}_{ccc}$ system, these optimized operators prove superior to combinations of limited plane-wave operators, enabling the resolution of distinct eigenstates separated by only $\sim 5\mathrm{MeV}$ near the threshold $2m_{{\mathrm{\Omega }}_{ccc}}\simeq 9700\mathrm{MeV}$. This exceptional resolving power opens new possibilities for studies of a wide range of hadronic systems in QCD.