We perform a model-independent measurement of the $D^0\text{−}{\overline{D}}^0$ mixing parameters using samples of $e^{+}{e}^{-}$ -collision data collected by the Belle and Belle II experiments that have integrated luminosities of $951{\mathrm{fb}}^{-1}$ and $408{\mathrm{fb}}^{-1}$, respectively. Approximately $2.05\times {10}^6$ neutral $D$ mesons are reconstructed in the $D^0\to K_{\mathrm{S}}^0{\pi }^{+}{\pi }^{-}$ channel, with the neutral $D$ flavor tagged by the charge of the pion in the $D^{*+}\to D^0{\pi }^{+}$ decay. Assuming charge-parity symmetry, the mixing parameters are measured to be $x=(4.0\pm 1.7\pm 0.4)\times {10}^{-3}$ and $y=(2.9\pm 1.4\pm 0.3)\times {10}^{-3}$, where the first uncertainties are statistical and the second systematic. The results are consistent with previous determinations.

We present a measurement of $|V_{ub}|$ from a simultaneous study of the charmless semileptonic decays $B^0\to {\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ and $B^{+}\to {\rho }^0{\ell }^{+}{\nu }_{\ell }$, where $\ell =e$, $\mu$. This measurement uses a data sample of 387 million $B\overline{B}$ meson pairs recorded by the Belle II detector at the SuperKEKB electron-positron collider between 2019 and 2022. The two decays are reconstructed without identifying the partner $B$ mesons. We simultaneously measure the differential branching fractions of $B^0\to {\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ and $B^{+}\to {\rho }^0{\ell }^{+}{\nu }_{\ell }$ decays as functions of $q^2$ (momentum transfer squared). From these, we obtain total branching fractions $\mathcal{B}(B^0\to {\pi }^{-}{\ell }^{+}{\nu }_{\ell })=(1.516\pm 0.042(\mathrm{stat})\pm 0.059(\mathrm{syst}))\times {10}^{-4}$ and $\mathcal{B}(B^{+}\to {\rho }^0{\ell }^{+}{\nu }_{\ell })=(1.625\pm 0.079(\mathrm{stat})\pm 0.180(\mathrm{syst}))\times {10}^{-4}$. By fitting the measured $B^0\to {\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ partial branching fractions as functions of $q^2$, together with constraints on the nonperturbative hadronic contribution from lattice QCD calculations, we obtain $|V_{ub}|=(3.93\pm 0.09\pm 0.13\pm 0.19)\times {10}^{-3}$. Here, the first uncertainty is statistical, the second is systematic, and the third is theoretical.

We present a novel way to probe inelastic dark matter using cosmic-ray (CR) cooling in active galactic nuclei (AGNs). Dark matter (DM) in the vicinity of supermassive black holes may scatter off CRs, resulting in the rapid cooling of CRs for sufficiently large cross sections. This in turn can alter the high-energy neutrino and gamma-ray fluxes detected from these sources. We show that AGN cooling bounds obtained through the multimessenger data of NGC 1068 and TXS $0506+056$ allows us to reach unprecedently large mass splittings for inelastic DM ($\gtrsim \mathrm{TeV}$), orders of magnitude larger than those probed by direct detection experiments and DM capture in neutron stars. Furthermore, we demonstrate that cooling bounds from AGNs can probe thermal light DM with small mass splittings. This provides novel and complementary constraints in parts of a parameter space accessible solely by colliders and beam-dump experiments.

In models with extended scalar sectors consisting of multiple Higgs doublets that trigger spontaneous electroweak symmetry breaking, it might be expected that the abundance of dimensionful quadratic couplings in the scalar potential could allow for a regime where, apart from the would-be Goldstone bosons and a neutral Higgs-like state, all new scalars have masses much larger than the electroweak scale. In the case of models where $CP$ invariance holds at the Lagrangian level but is broken by the vacuum, we show that such a reasonable expectation does not hold. When perturbativity requirements are placed on the dimensionless quartic couplings, the spectrum of the new scalars includes one charged and two additional neutral states whose masses cannot be much larger than the electroweak scale.

Supersymmetric models accompanied by certain anomaly-free discrete $R$ symmetries ${\mathbb{Z}}_n^R$ are attractive in that 1. the $R$ symmetry (which can arise from compactified string theory as a remnant of the broken 10-d Lorentz symmetry) forbids unwanted superpotential terms while allowing for the generation of an accidental, approximate global $U(1{)}_{PQ}$ symmetry needed to solve the strong $CP$ problem and 2. they provide a raison d’etre for an otherwise ad-hoc $R$-parity conservation. We augment the minimal supersymmetric Standard Model (MSSM) by two additional ${\mathbb{Z}}_n^R$- and Peccei-Quinn (PQ)-charged fields $X$ and $Y$ wherein supersymmetry (SUSY) breaking at an intermediate scale $m_{\text{hidden}}$ leads to PQ breaking at a scale $f_a\sim {10}^{11}\mathrm{GeV}$ leading to a SUSY Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) axion. The same SUSY breaking can trigger $R$-parity breaking via higher-dimensional operators leading to tiny $R$-violating couplings of order $(f_a/m_P{)}^N$ so that both $U(1{)}_{PQ}$ and $R$ parity emerge as accidental, approximate symmetries. For ${\mathbb{Z}}_4^R$ and ${\mathbb{Z}}_8^R$, we find only an $N=1$ suppression. Then the lightest SUSY particle (LSP) of the MSSM becomes unstable with a lifetime of order ${10}^{-3}-{10}^1$ s so the LSPs all decay away before the present epoch. That leaves a universe with all axion cold dark matter and no weakly interacting massive particles (WIMPs) in accord with recent LZ(2024) WIMP search results.

Light-cone distribution amplitudes (LCDAs) of heavy meson within heavy quark effective theory (HQET) are crucial for predicting physical observables in $B$ decays, but unfortunately there is no first-principle result due to severe challenges. After analyzing these challenges, we propose a realistic method to determine heavy meson LCDA. We utilize equal-time correlations and incorporate a dynamic quark field for a fast moving heavy quark. To verify this method, we make use of lattice QCD simulation on a lattice ensemble with spacing $a=0.05187\mathrm{fm}$. The preliminary findings for HQET LCDAs qualitatively align with phenomenological models, and the fitted result for the first inverse moment ${\lambda }_B^{-1}$ is consistent with the experimentally constrained region from $B\to \gamma \ell {\nu }_{\ell }$. We explore how our findings can reduce model uncertainties in predictions of heavy-to-light form factors at large recoil. These results demonstrate the promise of our method in providing first-principle predictions for heavy meson LCDAs.

The $X(3872)$, as the first and the most crucial member in the exotic charmoniumlike $XYZ$ family, has been studied for a long time. However, its dynamical origin, whether stemming from a $D{\overline{D}}^{*}$ hadronic molecule or the first excited $P$-wave charmonium ${\chi }_{c1}(2P)$, remains controversial. In this Letter, we demonstrate that the $X(3872)$ definitely does not result from the mass shift of the higher bare ${\chi }_{c1}(2P)$ resonance pole in the coupled-channel dynamics involving a short-distance $c\overline{c}$ core and the long-distance $D{\overline{D}}^{*}$ channels. Instead, it originates from either the $D{\overline{D}}^{*}$ molecular pole or the shadow pole associated with the antiresonance of the $P$-wave charmonium, depending on the weak or strong coupling mode, respectively. To differentiate these origins and fully exploit the nature of $X(3872)$, we conduct a comprehensive analysis in a couple-channel dynamics framework, including the isospin violation, the three-body $D\overline{D}\pi$ effect, the dynamical width of $D^{*}$, and nonopen-charm decays of the bare ${\chi }_{c1}(2P)$. Our findings highlight the pivotal role of the coupled-channel dynamics in explaining the disparity between the pole widths of $X(3872)$ and $T_{cc}^{+}$, while also predicting a new resonance with $J^{PC}=1^{++}$ around 4.0 GeV. By matching the newly observed ${\chi }_{c1}(4010)$ by the LHCb Collaboration to our predicted resonance, we conclude that the $X(3872)$ most likely originates from the $D{\overline{D}}^{*}$ pole with a confidence level exceeding 99.7%.

We reconstrue unconventional supersymmetry, a notion introduced by Alvarez-Valenzuela-Zanelli, as an attempt to use the framework of supersymmetric field theory to describe fermionic matter fields and bosonic gauge fields in a unified way, as parts of a single superconnection. It hinges upon the so-called matter ansatz. Unfortunately, the formal and conceptual status of the ansatz has remained unclear, preventing unconventional supersymmetry to be used in a principled way as a general approach beyond the model in which it was first considered. In this paper, we lift this restriction by showing that the ansatz is a special case of the dressing field method, a new systematic tool to exhibit the gauge-invariant content of general-relativistic gauge field theories.

Considering the Einstein-Hilbert truncation for the running action in (Euclidean) quantum gravity, we derive the renormalization group equations for the cosmological and Newton constant. We find that these equations admit only the Gaussian fixed point with a UV-attractive and a UV-repulsive eigendirection, and that there is no sign of the nontrivial UV-attractive fixed point of the asymptotic safety scenario. Crucial to our analysis is a careful treatment of the measure in the path integral that defines the running action and a proper introduction of the physical running scale $k$. We also show why and how in usual implementations of the RG equations the aforementioned UV-attractive fixed point is generated.

Obtaining the classification of three-dimensional (3D) $\mathcal{N}=4$ quivers whose Coulomb branches have an isolated singularity is an essential step in understanding moduli spaces of vacua of supersymmetric field theories with eight supercharges in any dimension. In this work, we derive a full classification for such Abelian quivers with arbitrary charges and identify all possible Coulomb branch geometries as quotients of ${\mathbb{H}}^n$ by U(1) or a finite cyclic group. We give two proofs, one which uses the “decay and fission” algorithm and another one relying only on explicit computations involving 3D mirror symmetry. In the process, we put forward a method for computing the 3D mirror of any $\mathrm{U}(1{)}^r$ gauge theory, which is sensitive to discrete gauge factors in the mirror theory. This constitutes a confirmation for the decay and fission algorithm.

The derivative expansion of the effective action is considered in the model with two interacting real scalar fields in curved spacetime. Using the functional approach and local momentum representation, the coefficient of the derivative term is calculated up to the first order in curvature in the one-scalar theory. The two-scalar problem is solved by extracting normal modes and consequent reduction to the single-scalar case. The method can be applied to a larger number of scalars. In the theory with strong hierarchy of masses, the renormalized effective potential and the coefficients of the second-order derivative terms demonstrate the quantum decoupling in the low-energy limit.

In this work, we show that a gauge-theoretic description of Jackiw-Teitelboim (JT) gravity naturally yields a Henneaux-Teitelboim (HT) unimodular gravity via a central extension of its isometry group, valid for both flat and curved two-dimensional spacetimes. HT gravity introduces a unimodular time canonically conjugate to the cosmological constant, serving as a physical time in quantum cosmology. By studying the minisuperspace reduction of ${\mathrm{HT}}_2$ gravity, the Wheeler-DeWitt equation becomes a Schrödinger-like equation, giving a consistent and unitary quantum theory. Analysis of the wave function’s probability density reveals a quantum distribution for the scale factor $a$, offering a quantum perspective on the expansion and contraction of the Universe. In this perspective, the possibility of reaching the singular point $a=0$ signals that topology change could occur. Finally, we give a consistent quantum description of unimodular time that aligns seamlessly with Page-Wootters formulation of quantum mechanics, where quantum correlations between unimodular time and JT gravity are studied in ${\mathrm{HT}}_2$ quantum cosmology.

The Weyl-type modified gravity theory is an extension of the $f(Q)$ and $f(Q,T)$ theories, where $T$ is the trace of the matter energy-momentum tensor, and the scalar nonmetricity $Q$ is represented in its standard Weyl form, which is fully determined by a vector field ${\omega }_{\mu }$. The theory provides a solid explanation of the observational data and the evolution of the late-time Universe, offering a geometric explanation of the dark energy. In this work, we investigate the big bang nucleosynthesis (BBN) constraints on several Weyl-type $f(Q,T)$ gravity models. We analyze in detail three distinct cosmological models, each corresponding to a specific choice of the functional form of $f(Q,T)$. The first model adopts a simple linear additive structure in $Q$ and $T$, the second model is multiplicative in $Q$ and $T$, while the third is additive in $T$ and the exponential of $Q$. For each $f(Q,T)$ model, we consider first the cosmological evolution in the radiation dominated era, and then we determine the constraints on the model parameters from the primordial abundances of the light element, helium-4, deuterium, and lithium-7. The abundances of helium-4 and deuterium agree with theoretical predictions, however, the lithium problem, even slightly alleviated, still persists for the considered Weyl-type $f(Q,T)$ models. Generally, these models satisfy the BBN constraints, and thus they represent viable cosmologies describing the entire dynamical timescale of the evolution of the Universe.

Deformations of spacelike hypersurfaces in space-time play an important role in discussions of general covariance and slicing independence in gravitational theories. In a canonical formulation, they provide the geometrical meaning of gauge transformations generated by the diffeomorphism and Hamiltonian constraints. However, it has been known for some time that the relationship between hypersurface deformations and general covariance is not a kinematical equivalence but holds only on the solution space of the constraints and requires their gauge equations and equations of motion to be used. The off-shell behavior of hypersurface deformations on their own, without imposing constraint and gauge equations, is therefore different from space-time diffeomorphisms. Its complete understanding is important for potential quantizations or modifications of general relativity in canonical form and of compatible space-time geometries that may be implied by them. Here, a geometrical analysis of hypersurface deformations is performed, allowing for a dependence of hypersurface deformation generators (the lapse function and the shift vector) on the phase-space degrees of freedom given by the geometry of an embedded spacelike hypersurface. The result is compared in detail with Poisson brackets of the gravitational constraints. As a new implication of physical relevance, covariance conditions are obtained for theories of emergent modified gravity without symmetry restrictions.

We consider an electric charge uniformly accelerating along the $x$ direction and moving with constant velocity along the $y$ direction. We show that while co-accelerating along the $x$ direction in the Rindler frame this charge creates a nonzero Poynting vector, which, however, does not lead to a nonvanishing flux through an infinitely distant surface. Furthermore, we show that in the laboratory Minkowski frame such a charge creates a stress energy flux that does not vanish at infinity. We interpret these observations as that while the Rindler frame corresponds to the static zone around the charge, the Minkowski frame does contain the wave zone. We give detailed calculations and explanations concluding that a uniformly accelerating charge does radiate.

Binary black hole systems are typically assumed to evolve in vacuum. However, the environment surrounding the binary components can influence their properties, such as their tidal deformability, affecting the gravitational waveform produced by the binary and its interpretation in gravitational wave data analysis. In this work we focus on next-generation experiments, such as the Einstein Telescope and LISA, and we quantify the systematic biases in gravitational wave observations that arise when tidally deformed binaries are interpreted as occurring in vacuum. We consider binaries over a range of masses and we compare different phenomenological models for the dynamical evolution of the tidal deformability. We find that systematic biases could significantly affect the measurability of the binary parameters if tidal effects are not carefully modeled.

The intrinsic alignment (IA) of galaxy shapes probes the underlying gravitational tidal field, thus offering cosmological information complementary to galaxy clustering. In this paper, we perform a Fisher forecast to assess the benefit of IA in improving cosmological parameter constraints, for the first time, leveraging the full-shape (FS) information of IA statistics. Our forecast is based on Subaru Prime Focus Spectrograph-like and Euclid-like surveys as examples of deep and wide galaxy surveys, respectively. We explore various cosmological models, with the most comprehensive one simultaneously including dynamical dark energy, curvature, massive neutrinos, and modified gravity (MG). We find that adding FS IA information significantly tightens cosmological constraints relative to the FS clustering-only cases, particularly for dynamical dark energy and nonflat-MG models. For a deep galaxy survey, the figure of merit for the dark energy equation of state parameters is improved by at least more than 40% in all dynamical dark energy models investigated. For nonflat-MG models, parameter constraints are tightened by 6%–28%, except for the dark matter density and spectral index parameters. For a wide galaxy survey, improvements with IA become milder, although its joint constraints are tighter than those from the deep survey. Our findings highlight the efficacy of the galaxy IA as a complementary cosmological probe to galaxy clustering.

Domain walls are the simplest type of topological defects formed at cosmological phase transitions, and one of the most constrained. Their studies typically assume a quartic double well potential, but this model is not fully representative of the range of known or plausible particle physics models. Here, we study the cosmological evolution of domain walls in two other classes of potentials. The Sine-Gordon potential allows several types of walls, interpolating between different pairs of minima (which demands specific numerical algorithms to separately measure the relevant properties of each type). The Christ-Lee potentials parametrically interpolates between sextic and quartic behavior. We use multiple sets of simulations in two and three spatial dimensions, for various cosmological epochs and under various choices of initial conditions, to discuss the scaling properties of these networks. In the Sine-Gordon case, we identify and quantify deviations from the usual scaling behavior. In the Christ-Lee case, we discuss conditions under which walls form (or not) and quantify how these outcomes depend on parameters such as the energy difference between the false and true vacua and the expansion rate of the Universe. Various biased initial conditions are also addressed in the Appendixes. Finally, we briefly comment on the possible cosmological implications of our results.

We investigate the effect of potentially large distortions of the relic neutrino spectra on cosmological observables. To that end, we consider a phenomenological model of “gray” spectral distributions, described by a single parameter, which generalizes the traditional $y$-distortions to possibly large negative values. Implementing these distortions in the primordial nucleosynthesis code primat, we can constrain the distortion parameter along with the presence of extra radiation, exploiting the complementarity of big bang nucleosynthesis and cosmic microwave background measurements to disentangle gravitational and nonthermal effects. These constraints rule out a distortion where more than $\sim 1/2$ of the neutrinos’ energy density is replaced by dark radiation. Nonetheless, we find that large distortions, accompanied with extra radiation, are allowed—and even slightly preferred in some cases—by current cosmological observations. As this scenario would require substantial modifications to the physics of neutrino decoupling in the early Universe, these observational constraints call for a renewed attention on the possibility of large deviations from the standard cosmological model in the neutrino sector.