In this paper, we take into account the intrinsic charm and gluonic contents into the $\eta -{\eta }^{\prime }$ mixing scheme and formulate the tetramixing $\eta -{\eta }^{\prime }-G-{\eta }_c$ to study the mixing properties of ${\eta }^{(\prime )}$ mesons. Using the newly derived mixing parameters, we calculate the transition form factors (TFFs) of $B^{+}/D^{+}/D_s^{+}\to {\eta }^{(\prime )}$ within the quantum chromodynamics (QCD) light-cone sum rules up to next-to-leading order QCD corrections and twist-4 contributions. Using the extrapolated TFFs, we then calculate the decay widths and branching fractions of the semileptonic decays $B^{+}/D^{+}/D_s^{+}\to {\eta }^{(\prime )}{\ell }^{+}{\nu }_{\ell }$. Our results are consistent with the recent Belle and BES-III measurements within reasonable errors.

A new dark matter candidate is proposed that arises as the lightest baryon from a confining $SU(N)$ gauge theory which equilibrates with the Standard Model only through electroweak interactions. Surprisingly, this candidate can be as light as a few GeV. The lower bound arises from the intersection of two competing requirements: (i) the equilibration sector of the model must be sufficiently heavy, at least several TeV, to avoid bounds from colliders, and (ii) the lightest dark meson (that may be the dark ${\eta }^{\prime }$, $\sigma$, or the lightest glueball) has suppressed interactions with the SM and must decay before big bang nucleosynthesis. The low-energy dark sector consists of one flavor that is electrically neutral and an almost electroweak singlet. The dark matter candidate is the lightest baryon consisting of $N$ of these light flavors leading to a highly suppressed elastic scattering rate with the Standard Model (SM). The equilibration sector consists of vectorlike dark quarks that transform under the electroweak group, ensuring that the dark sector can reach thermal equilibrium with the SM in the early Universe. The lightest dark meson lifetimes vary between ${10}^{-3}\lesssim c\tau \lesssim {10}^7\mathrm{m}$, providing an outstanding target for LHC production and experimental detection. We delineate the interplay between the lifetime of the light mesons, the suppressed direct detection cross section of the lightest baryon, and the scale of equilibration sector that can be probed at the LHC.

In this article, we study the significance of string loop corrections, in a perturbative moduli stabilization scenario, focusing on their role in unraveling the origin of dark radiation in the late cosmological epoch and their correlation to dark matter. More specifically, a detailed analysis is provided in which the mass hierarchy of the normalized fields in the Kähler moduli sector is determined by the scales of the integer fluxes and the quantum corrections. Furthermore, we compute the previously underestimated contributions to the decay rates of moduli to axions, which behave as dark radiation, highlighting their connection to the aforementioned higher-order corrections. Two contrasting reheating scenarios (low scale and high scale) are provided, depending on the decay rate of the longest-lived particle into the Standard Model degrees of freedom through a Giudice-Masiero mechanism, while the effective number of neutrino species $\mathrm{\Delta }{N}_{\mathrm{eff}}$ remains below the respective bounds. Finally, a nonthermal dark matter scenario is proposed based on the decays of heavy scalar fields, where the main production mechanisms are investigated, leading to a dark matter candidate mass ranging from a few GeV up to ${10}^{12}\mathrm{GeV}$.

Dark matter (DM) remains one of the most compelling unresolved problems in fundamental physics, motivating the search for new detection approaches. We propose a network-based quantum sensor architecture to enhance sensitivity to ultralight DM fields. Each node in the network is a superconducting qubit, interconnected via controlled-Z gates in symmetric topologies such as line, ring, star, and fully connected graphs. We investigate four- and nine-qubit systems, optimizing both state preparation and measurement using a variational quantum metrology framework. This approach minimizes the quantum and classical Cramér-Rao bounds to identify optimal configurations. Bayesian inference is employed to extract the DM-induced phase shift from measurement outcomes. Our results show that optimized network configurations significantly outperform conventional Greenberger-Horne-Zeilinger-based protocols while maintaining shallow circuit depths compatible with noisy intermediate-scale quantum hardware. Sensitivity remains robust under local dephasing noise. These findings highlight the importance of network structure in quantum sensing and point toward scalable strategies for quantum-enhanced DM detection.

We study 3D anti–de Sitter minimal massive gravity in two regimes: a) at the chiral limit where one of the boundary Brown-Henneaux central charges vanishes and two modes become null and b) in the regime where one of the two charges is much larger than the other. At the chiral point, we go beyond the known free-theory analysis to prove that these modes decouple completely also in the full MMG Lagrangian and field equations. We also use the full action to ascertain if the interacting theory becomes infinitely strongly coupled in the neighborhood of the chiral limit, where the theory is not unitary. We show that this is not the case at tree level but that a strong coupling pathology appears in loops, starting at a loop level determined by the number of external legs in the bulk Feynman diagrams. Finally, we show that there is no strong coupling problem in the second regime where, instead, the two boundary fields and the field propagating in the bulk decouple from one another.

Oscillations in the primordial bispectrum are sourced by a range of inflationary phenomena, including features in the inflaton potential and interactions with massive fields through the Cosmological Collider scenario. These signatures offer a powerful window into early-universe physics. In this work, we study how oscillations of the form ${\lim }_{q\ll k}B(q,k)\propto \cos (\mu \ln (q/k))$ impact the nonlinear squeezed matter bispectrum. Using a suite of $N$-body simulations with non-Gaussian initial conditions, we show that nonlinear evolution significantly damps these oscillations, effectively erasing the signal on scales $k\gtrsim 0.3h/\mathrm{Mpc}$ at redshift $z=0$. This damping is well described by the Zel’dovich approximation and can be modeled deep into the nonlinear regime using nonperturbative separate universe simulations. Promisingly, we show that reconstruction techniques developed for baryon acoustic oscillation analyses can largely undo this damping, improving constraints on the amplitude (phase) of oscillations in the primordial squeezed bispectrum by up to a factor of five (four) at $z=0$. We also discuss several challenges with modeling the nonlinear evolution of the squeezed bispectrum in the Cosmological Collider scenario, where the bispectrum is suppressed by a factor of $(q/k{)}^{3/2}$ relative to the template studied here. Our findings pave the way for future searches for oscillatory bispectra using large-scale structure data.

Gravitational waves from inspiraling compact binaries provide direct measurements of luminosity distances and serve as a powerful probe of the high-redshift Universe. In addition to their role as standard sirens, they offer an opportunity to constrain small-scale density fluctuations through the dispersion in the distance–redshift relation induced by gravitational lensing. We propose a method to constrain this lensing dispersion without requiring the redshift information by analyzing the angular clustering of gravitational wave sources. Our formalism incorporating second-order lensing effects in the luminosity distance shows that the amplitude of the autocorrelation angular clustering decreases with increasing lensing dispersion. While we show that the autocorrelation signal is detected with sufficient signal-to-noise ratios in future gravitational wave experiments, there exists a strong degeneracy between the lensing dispersion and the linear bias of gravitational wave sources. We demonstrate that this degeneracy is partially broken by a joint analysis of the autocorrelation of gravitational wave sources and the cross-correlation with galaxies whose redshifts are known. This approach enhances the use of gravitational waves as a cosmological probe at high redshifts.

In the Standard Model, neutrinos are massless. However, oscillation experiments demonstrate that they do have a small mass. Currently, only the differences of the masses squared are known, along with an upper bound on their sum. Upcoming surveys of the Universe’s Large-Scale Structure offer a promising avenue to probe neutrino mass by revealing how neutrinos influence galaxy clustering. Massive neutrinos affect mode coupling within the framework of Perturbation Theory (PT) for structure formation, leaving detectable signatures in the PT kernels. In this work, we present for the first time the explicit modifications to the kernels caused by massive neutrinos and investigate the extent of these changes in the redshift-space galaxy bispectrum. To this end, we generate synthetic data using a theoretical covariance matrix and employ Markov-chain Monte Carlo to assess the impact of these new signature terms. This approach, in contrast to Fisher forecasting, allows us to see if the new terms induce shifts in the recovered central values of parameters. The synthetic data are produced to mirror two different galaxy samples. The first corresponds to the Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey Data Release 12 CMASS Luminous Red Galaxy (LRG) sample, characterized by an effective volume of $V_{\mathrm{eff}}=3[\mathrm{Gpc}/h{]}^3$ and a number density of $\overline{n}=3\times {10}^{-4}h/\mathrm{Mpc}$. The second corresponds to the Dark Energy Spectroscopic Instrument (DESI) Year 5 LRG sample with $V_{\mathrm{eff}}=25[\mathrm{Gpc}/h{]}^3$. Our findings indicate that neglecting neutrino mass effects in the kernels can result in a central value shift equivalent to approximately $1\sigma$ in the galaxy biases estimated from the DESI Y5-like sample and no observable shift of the cosmological parameters.

Neutron star-black hole (NSBH) mergers, detectable via their gravitational-wave (GW) emission, are expected to produce kilonovae (KNe). Four NSBH candidates have been identified and followed-up by more than fifty instruments since the start of the fourth GW observing run (O4), in May 2023, up to July 2024; however, no confirmed associated KN has been detected. This study evaluates ejecta properties from multimessenger observations to understand the absence of detectable KN: we use GW public information and joint observations taken from 05.2023 to 07.2024 (LVK, ATLAS, DECam, GECKO, GOTO, GRANDMA, SAGUARO, TESS, WINTER, ZTF). First, our analysis on follow-up observation strategies shows that, on average, more than 50% of the simulated KNe associated with NSBH mergers reach their peak luminosity around one day after merger in the $g$, $r$, $i$- bands, which is not necessarily covered for each NSBH GW candidate. We also analyze the trade-off between observation efficiency and the intrinsic properties of the KN emission, to understand the impact on how these constraints affect our ability to detect the KN, and underlying ejecta properties for each GW candidate. In particular, we can only confirm the kilonova was not missed for 1% of the GW230529 and S230627c sky localization region, given the large sky localization error of GW230529 and the large distance for S230627c and, their respective KN faint luminosities. More constraining, for S230518h, we infer the dynamical ejecta and postmerger disk wind ejecta $m_{\mathrm{dyn}},m_{\mathrm{wind}}<0.03M_{\odot }$ and the viewing angle $\theta >25°$. Similarly, the nonastrophysical origin of S240422ed is likely further confirmed by the fact that we would have detected even a faint KN at the time and presumed distance of the S240422ed event candidate, within a minimum 45% credible region of the sky area, that can be larger depending on the KN scenario.

Supernova-neutrino-boosted dark matter ($\mathrm{SN}\nu$ BDM) has emerged as a promising portal for probing sub-GeV dark matter. In this work, we investigate the behavior of BDM signatures originating from core-collapse supernovae within the Milky Way (MW) over the past one hundred thousand years, examining both their temporal evolution and present-day spatial distributions. We show that while the MW BDM signature is approximately diffuse in the nonrelativistic regime, it exhibits significant temporal variation and spatial localization when the BDM is relativistic. Importantly, we compare these local MW signatures with the previously proposed diffuse $\mathrm{SN}\nu$ BDM (DBDM), which arises from the accumulated flux of all past supernovae in the Universe [Y.-H. Lin and M.-R. Wu, Phys. Rev. Lett. 133, 111004 (2024)]. In the nonrelativistic limit, DBDM consistently dominates over the local diffuse MW BDM signature. Only when the MW BDM becomes ultrarelativistic and transitions into a transient, highly localized signal can it potentially surpass the DBDM background. This work thus reinforces the importance of DBDM for $\mathrm{SN}\nu$ BDM searches until the next galactic SN offers new opportunities.

The absence of direct evidence for new physics at current collider energies motivates the study of indirect effects within the framework of the Standard Model effective field theory (SMEFT). In this work, we investigate the role of the $A_4$ discrete flavor symmetry in constraining the UV dynamics, giving rise to dimension-six SMEFT operators involving leptons. We consider renormalizable interactions between SM fields and heavy mediators, classified according to their $A_4$ transformation properties in the modular framework, where Yukawa structures are encoded in modular forms. Restricting our analysis to UV interactions with at most a single modular form insertion, we study the resulting classification of $A_4$ UV mediator irreducible representations and explore their implications across a range of observables, including both lepton-flavor-conserving and lepton-flavor-violating processes. A detailed phenomenological analysis is carried out, incorporating both tree-level and one-loop matching contributions for scalar and fermionic mediators, as well as leading-log renormalization group equation effects in case of vectors.

We illustrate how the future electron-ion collider (EIC) can be used to discover dark bosons with masses in the $\sim (10\mathrm{MeV}\text{−}10\mathrm{GeV})$ regime, having a wide range of properties. We only require that the dark bosons have a non-negligible weak coupling to electrons and decay with the $\mathcal{O}(1)$ branching fraction into invisible final states. Our signal selection takes advantage of the excellent electron beam kinematic measurements and the capability to tag incoherent scattering, as envisioned at the EIC. This makes the EIC a powerful tool for uncovering potential dark sector forces, for a variety of possibilities.

In this paper, we develop an approach to calculate the valence-quark quasiparton distribution amplitude (quasi-PDA) and quasiparton distribution function (quasi-PDF) for the pion with a large longitudinal momentum with the functional renormalization group (fRG). This is demonstrated in a low energy effective theory (LEFT) with four-quark scatterings. In the study of the complex structure of quasi-PDA, we introduce a deformed integration contour in the calculations of quasi-PDA or quasi-PDF, which allows us to obtain correct integrals for all momentum fractions. It is found that the pion light-front PDA extrapolated from quasi-PDA based on the large momentum effective theory in the LEFT is comparable with lattice QCD and Dyson-Schwinger equation. This work paves the way to study the PDA and PDF within the fRG approach to first-principles QCD.

We investigate energy bounds and the stability of stationary asymptotically flat spacetimes with an ergoregion and no future horizon in the context of Einstein-Maxwell-scalar field models that naturally arise in Kaluza-Klein and string theories. In order to do that, we consider scalar field perturbations nonminimally coupled to a background electromagnetic field. We show that there is compactly supported initial data such that the initial energy flux across the initial Cauchy hypersurface is negative and that the energy flux decreases with time. Then, considering arguments due to Friedman and Moschidis, this indicates that the energy flux diverges for those solutions and such spacetimes with an ergoregion are unstable.

Primordial black holes (PBHs) with masses between ${10}^{14}$ and ${10}^{20}\mathrm{kg}$ are candidates to contribute a substantial fraction of the total dark matter abundance. When in orbit around the center of a star, which can possibly be a completely interior orbit, such objects would emit gravitational waves, as predicted by general relativity. In this work, we examine the gravitational wave signals emitted by such objects when they orbit typical stars, such as the Sun. We show that the magnitude of the waves that could eventually be detected on Earth from a possible PBH orbiting the Sun or a neighboring Sun-like star within our Galaxy can be significantly stronger than those originating from a PBH orbiting a denser but more distant neutron star. Such signals may be detectable by the LISA gravitational wave detector. In addition, we estimate the contribution that a large collection of such PBH-star systems would make to the stochastic gravitational wave background within a range of frequencies to which pulsar timing arrays are sensitive.

Recently, there has been interest in the applicability of quantum statistics to distinguish Dirac from Majorana neutrinos in multineutrino final states. In particular, debate has arisen over the validity of the Dirac-Majorana confusion theorem in these processes, i.e., that any distinction between the Dirac and Majorana processes goes to zero as the neutrino mass goes to zero. Here we approach this problem equipped with spinor-helicity methods generalized for massive Dirac and Majorana fermions. We explicitly calculate all helicity amplitudes, and their squares, for the decay of a light scalar particle to two neutrinos and two oppositely charged leptons. This allows us to pinpoint the crucial steps which could lead to claims of a violation of the confusion theorem. We show that, if the correct antisymmetrization of Dirac to Majorana amplitudes is used, identification of which is clear in this framework, and all relevant contributions are appropriately summed, a scalar decay into two charged leptons and two neutrinos satisfies the Dirac-Majorana confusion theorem.

In the poltergeist mechanism the enhancement of induced gravitational waves (GWs) occurs due to a sudden transition from an early matter-dominated era to the radiation-dominated era. In this work, we calculate the bispectrum of induced GWs from the poltergeist mechanism by adopting the sudden transition approximation. We find that the tensor bispectrum peaks either in the equilateral or squeezed configurations, depending on scales. Such a characteristic behavior enables us to distinguish it from that from other GW generation mechanisms.

Recently, the wavefunction coefficients for conformally coupled scalars in an Friedmann-Robertson-Walker cosmology have been presented as a sum over amplitudelike functions known as amplitubes. In this work, we extend this analysis to full correlation functions. Remarkably, the amplitube expansion of the correlator exhibits many vanishing contributions that are otherwise present in the expansion of the wavefunction. Moreover, while the wavefunction coefficients suffer from relative minus signs between terms, the surviving terms in thte correlation function do not. These observations point to a hidden simplicity in the structure of the correlation function compared to that of the wavefunction coefficient.

This letter introduces a novel analytical approach to calculating phase-space integrals, crucial for precision in particle physics. We develop a method to compute angular components using multifold Mellin-Barnes integrals, yielding results in terms of Goncharov polylogarithms for integrals involving three denominators. Our results include expressions for massless momenta to $\mathcal{O}({\epsilon }^2)$ and for massive momentum to $\mathcal{O}(\epsilon )$. We derive recursion relations that reduce integrals with higher powers of denominators to simpler ones. We detail how to combine the angular part with the radial one which requires a careful handling of singularities.