We present a lattice quantum chromodynamics (QCD) calculation of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon using $N_f=2+1+1$ flavors of staggered quarks with masses tuned to their physical values. Our final result, in the continuum limit, reads $a_{\mu }^{\mathrm{hlbl}}=125.5(11.5{)}_{\mathrm{stat}}(1.9{)}_{\mathrm{syst}}\times {10}^{-11}$ where the first error is statistical and the second is systematic. Light, strange, and charm-quark contributions are considered. In addition to the connected and leading disconnected contributions, we also include an estimate of the subleading disconnected diagrams. Our result is compatible with previous lattice QCD and data-driven dispersive determinations.

We study the effect of finite spin quark density on the chiral and deconfinement thermal crossovers using numerical simulations of lattice QCD with two dynamical light quarks. The finite spin density is introduced by the quark spin potential in the canonical formulation of the spin operator. We show that both chiral and deconfinement temperatures are decreasing functions of the spin potential. We determine the parabolic curvatures of crossover temperatures in a limit of physical quark masses.

We report the first Dyson-Schwinger equation predictions for the leading-twist distribution amplitudes of the $B^{*}$, $B_s^{*}$, and $B_c^{*}$ mesons, and extend the investigation to a broader set of heavy-light pseudoscalar/vector mesons. Numerical analysis shows that, in flavor-asymmetric systems, the distribution amplitude is skewed toward the heavier quark, with the position of the maximum $\sim M_E^f/(M_E^f+M_E^g)$, where $M_E$ is the Euclidean constituent quark mass and $f$, $g$ denote the quark flavors. Spin effects are found to be subleading compared to the influence of valence-quark composition, and lead to heavier quarks carrying more light-front momentum in vector mesons than in their pseudoscalar counterparts. Our results can be compared with both experimental and theoretical outcomes in the future.

In the present work, we propose to investigate the productions of ${\mathrm{\Lambda }}_c(2910)$ and ${\mathrm{\Lambda }}_c(2940)$ in the ${\pi }^{-}p\to D^{-}{D}^{0}p$ processes by utilizing an effective Lagrangian approach, where ${\mathrm{\Lambda }}_c(2910)$ and ${\mathrm{\Lambda }}_c(2940)$ are considered as $D^{*}N$ molecular states with $J^P$ quantum numbers to be $1/2^{-}$ and $3/2^{-}$, respectively. With the cutoff parameter determined by the upper limit of the cross sections for ${\pi }^{-}p\to D^{*-}{\mathrm{\Lambda }}_c(2286)$, the ratios of the cross sections for ${\pi }^{-}p\to D^{*-}{\mathrm{\Lambda }}_c(2286)$, ${\pi }^{-}p\to D^{-}{\mathrm{\Lambda }}_c(2286)$, ${\pi }^{-}p\to D^{-}{\mathrm{\Lambda }}_c(2910)$, and ${\pi }^{-}p\to D^{-}{\mathrm{\Lambda }}_c(2940)$ are estimated to be $1:4.8:1.42:0.26$ at $p_{\pi }=30\mathrm{GeV}$. Considering that the ${\mathrm{\Lambda }}_c(2910)$ and ${\mathrm{\Lambda }}_c(2940)$ state can further decay into $D^{0}p$, we estimate the cross sections for ${\pi }^{-}p\to D^{-}{D}^{0}p$ process and the differential cross sections depending on the $D^{0}p$ invariant mass spectrum. Our estimations indicate that the total cross sections are $(0.49_{-0.38}^{+1.56})\mathrm{nb}$ when $p_{\pi }=15\mathrm{GeV}$, where the uncertainties result from the variation of the ${\mathrm{\Lambda }}_r$. By comparing the contributions of the $s$, $u$, and $t$-channels, we conclude that the $t$-channel plays the predominant role. Moreover, the present estimations suggest that the structure around 2.9 GeV in the $D^{0}p$ invariant mass spectrum of the ${\pi }^{-}p\to D^{-}{D}^{0}p$ process should correspond to ${\mathrm{\Lambda }}_c(2910)$ rather than ${\mathrm{\Lambda }}_c(2940)$, which can be tested by further experimental measurements at J-PARC in the future.

The production yields of the orbitally excited charm-strange mesons ${\mathrm{D}}_{\mathrm{s}1}(1^{+})(2536{)}^{+}$ and ${\mathrm{D}}_{\mathrm{s}2}^{*}(2^{+})(2573{)}^{+}$ were measured for the first time in proton-proton (pp) collisions at a center-of-mass energy of $\sqrt{s}=13\mathrm{TeV}$ with the ALICE experiment at the LHC. The ${\mathrm{D}}_{\mathrm{s}1}^{+}$ and ${\mathrm{D}}_{\mathrm{s}2}^{*+}$ mesons were measured at midrapidity ($|y|<0.5$) in minimum-bias and high-multiplicity pp collisions in the transverse-momentum interval $2<p_{\mathrm{T}}<24\mathrm{GeV}/c$. Their production yields relative to the ${\mathrm{D}}_{\mathrm{s}}^{+}$ ground-state yield were found to be compatible between minimum-bias and high-multiplicity collisions, as well as with previous measurements in ${\mathrm{e}}^{\pm }\mathrm{p}$ and ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ collisions. The measured ${\mathrm{D}}_{\mathrm{s}1}^{+}/{\mathrm{D}}_{\mathrm{s}}^{+}$ and ${\mathrm{D}}_{\mathrm{s}2}^{*+}/{\mathrm{D}}_{\mathrm{s}}^{+}$ yield ratios are described by statistical hadronization models and can be used to tune the parameters governing the production of excited charm-strange hadrons in Monte Carlo generators, such as pythia 8.

A search for heavy neutral gauge bosons ($Z^{\prime }$) decaying into a pair of tau leptons is performed in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ at the CERN LHC. The data were collected with the CMS detector and correspond to an integrated luminosity of $138{\mathrm{fb}}^{-1}$. The observations are found to be in agreement with the expectation from standard model processes. Limits at 95% confidence level are set on the product of the $Z^{\prime }$ production cross section and its branching fraction to tau lepton pairs for a range of $Z^{\prime }$ boson masses. For a narrow resonance in the sequential standard model scenario, a $Z^{\prime }$ boson with a mass below 3.5 TeV is excluded. This is the most stringent limit to date from this type of search.

It has been shown that entanglement and Bell nonlocality, which are key concepts in quantum mechanics, can be probed in high-energy colliders via processes of fundamental particle scattering. In fact, the ATLAS and CMS Collaborations have measured entanglement using top-quark pairs produced in proton-proton collisions at the LHC. Recently, it was shown that spin correlations can be measured in pairs of bottom quarks at the LHC, despite the fact that bottom quarks, unlike top quarks, hadronize before decaying. Here, we demonstrate that quantum correlations can also be studied using bottom-quark pairs, and analyze the feasibility of the observation of entanglement and Bell nonlocality in several collider experiments. Given the low mass of the bottom quark relative to typical energies accessible at the LHC, many of the bottom-quark pairs are in the ultrarelativistic regime, where they can exhibit strong spin entanglement. We find that entanglement of bottom-quark pairs may be measurable even with the LHC Run 2 data, especially with the CMS $B$ parking dataset, while observation of Bell nonlocality may become feasible at the high-luminosity phase of the LHC.

In this work, we construct an explicit string motivated example of three-field inflation related to, yet distinct from the recently discovered perturbative large volume scenario (pLVS). In this setup, large volume is ensured by the interplay between the effects of ${\alpha }^{\prime 3}$, logarithmic loop, and higher derivative $F^4$ corrections. After addressing full moduli stabilization, we move on to a detailed analysis of a three-field model of inflation while choosing a suitable canonical basis for the fields. Our model differs from previous setups in three key aspects: first, the interaction between subleading corrections that drive full moduli stabilization is different compared to pLVS for instance; second, the volume of the underlying Calabi-Yau is of “weak-Swiss-cheese” type; and third, in our three-field inflationary scenario, the second Hubble slow-roll parameter consistently dominates over the first by several orders of magnitude—primarily due to the steepness of the potential. When this hierarchy is aided by a brief deviation from slow roll, an enhancement in the primordial power spectrum can be naturally achieved. We have obtained two stages of inflation: the first stage mostly occurs when one of the inflatons roll along the steepest direction—completing 55 e-folds of inflation. Once the rolling inflaton falls off a ridge of the multifield potential, the other two fields become active, giving us a true multifield behavior in the second stage—adding few more e-folds of inflation. Inflation ends when all three of them roll toward the global minimum and settle there. We confirm this behavior by introducing the nonplanar torsion in the inflationary trajectory—this quantity becomes nontrivial in the second stage of inflation. Finally, we calculate the cosmological observables, which align with the Planck data, and discuss potential directions for future research.

We clarify the relation between the classical double copy and the double copy for amplitudes in the setting of self-dual gauge and gravity theories. To this end we construct explicit all-order perturbative solutions in these theories and show that they are related by a version of color-kinematics duality. This relation can be expressed in a double-copy form and embodies the most general manifestation of the self-dual classical double copy. Our classical double-copy relations directly lead to known amplitude double-copy relations, both for Berends-Giele currents and on-shell amplitudes, through the perturbiner expansion.

In this study, we calculate the $m-1$ correction to the reflected entropy for two adjacent intervals on a half-infinite line within the ${\mathrm{AdS}}_3/{\mathrm{BCFT}}_2$ framework, where $m$ is a Renyi index for a canonical purification. We utilize the doubling trick and compute the leading terms in the large central charge expansion of correlation functions in the holographic boundary conformal field theory (BCFT). In the corresponding anti–de Sitter (AdS) space with an end of the world brane, we analyze the entanglement wedge cross section, the dual counterpart of reflected entropy. This AdS/BCFT setup allows us to explore a richer set of phases in the entanglement wedge cross section. The $m-1$ correction in the holographic BCFT manifests as modifications in the entanglement wedge cross section induced by cosmic branes. For the adjacent intervals anchored to the boundary of BCFT, we show the duality between the entanglement wedge cross section with the backreaction from a cosmic brane and Renyi reflected entropy at all orders in $m-1$. Furthermore, by analyzing the entanglement wedge cross section for general adjacent intervals, we provide guidance for an $\epsilon$ expansion of five-point functions in the holographic conformal field theory (CFT), where $\epsilon$ is the rescaled conformal dimension by the central charge.

The Swampland cobordism conjecture [arXiv:1909.10355.] predicts various new objects in a theory with dynamical gravity. Applying this idea to the Standard Model of particle physics, a string object is predicted. We numerically constructed such an object as a black string solution.

In this paper, we derive five-dimensional non-Abelian $\mathcal{N}=1$ Chern-Simons action from its proposed definition of variation with respect to an infinitesimal deformation of the vector prepotential in a projective superspace setting. It has been a long-standing open problem how to integrate this variation. Now, thanks to the simplicity of a projective superspace technique, we are finally able to obtain this term. Our final result is expressed in terms of the real prepotential multiplets and projective covariant derivatives. The action reduces to the correct formula in the Abelian limit. As a bonus, we also give the supersymmetric Yang-Mills action with a half measure.

In this paper, we study the trajectories of massive and massless particles in four-dimensional static and spherically symmetric black holes in the de Rham–Gabadadze–Tolley massive gravity theory via phase-plane analysis and point out several novel features. In particular, we show the existence of a static sphere, a finite radial distance outside the black holes in these theories, where a massive particle can be at rest, as seen by an asymptotic zero-angular-momentum observer. Topological arguments show that stable and unstable static spheres, which come in pairs, have opposite charges. In the presence of angular momentum, we first study the behavior of massless particles and find the presence of stable and unstable photon spheres in both neutral and charged black holes. Subsequently, we study the motion of massive test particles around these black holes, and we find one pair of stable and unstable timelike circular orbits (TCOs), such that the stable and unstable TCOs are disconnected in certain regions. Computing the angular velocity ${\mathrm{\Omega }}_{\mathrm{CO}}$ of the TCOs, measured by a static observer at rest, shows the unusual nature of its monotonic increase with the radius of the TCO near the location of a stable photon sphere. This confirms the existence of the Aschenbach effect for spherically symmetric black holes in massive gravity, which was only found to exist in rapidly spinning black holes, with the only other exception being the rare example of gravity coupled to quasitopological electromagnetism.

We point out that inflationary superhorizon fluctuations can be effectively described by a set of equations analogous to those governing a superfluid. This is achieved through a functional Schrödinger approach to the evolution of the inflationary wave function, combined with a suitable coarse-graining procedure to capture large-scale dynamics. The irrotational fluid velocity is proportional to the gradient of the wave-function phase. Marginalizing over short superhorizon modes introduces an external force acting on the fluid velocity. The quantum pressure characteristic of the superfluid plays a role in scenarios involving an ultra-slow-roll phase of inflation. Our superfluid framework is consistent with the standard Starobinsky approach to stochastic inflation while offering complementary insights, particularly by providing more precise information on the phase of the inflationary wave function. We also discuss a heuristic approach to include dissipative effects in this description.

Axionlike scalar fields can induce temporary deviations from the standard expansion history of the Universe. The scalar field’s contribution to the energy density of the Universe grows while the field is held constant by Hubble friction, but when the scalar field starts to evolve, its energy density decreases faster than the radiation density for some potentials. We explore the observational signatures of such a scalar field that becomes dynamical between big bang nucleosynthesis and matter-radiation equality, which we call very early dark energy (vEDE). If vEDE momentarily dominates the energy density of the Universe, it generates a distinctive feature in the matter power spectrum that includes a bump on scales that enter the horizon just after the scalar field starts to evolve. For $k\gtrsim 10h{\mathrm{Mpc}}^{-1}$, the amplitude of this bump can exceed the amplitude of the standard matter spectrum. The power on scales on either side of this peak is suppressed relative to the standard power spectrum, but only scales that are within the horizon while the scalar field makes a significant contribution to the total energy density are affected. We determine how vEDE scenarios are constrained by observations of the cosmic microwave background, measurements of the primordial deuterium abundance, and probes of the late-time expansion history. We find that these observations are consistent with vEDE scenarios that enhance power on scales $k\gtrsim 30h{\mathrm{Mpc}}^{-1}$ and nearly double the amplitude of the matter power spectrum around $200h{\mathrm{Mpc}}^{-1}$. These scenarios also suppress power on scales between 0.3 and $30h{\mathrm{Mpc}}^{-1}$.

If QCD axion dark matter formed postinflation, axion miniclusters emerged from isocurvature fluctuations and later merged hierarchically into minihalos. These minihalos, potentially disrupted by stellar encounters in the Milky Way, affect axion detectability. We extend prior analyses by more accurately incorporating multiple stellar encounters and dynamical relaxation timescales, simulating minihalo orbits in the Galactic potential. Our results show stellar interactions are more destructive than previously estimated, reducing minihalo mass retention at the solar system to 30%, compared to earlier estimates of 60%. This enhanced loss arises from cumulative energy injections when relaxation periods between stellar encounters are accounted for. The altered minihalo mass function implies a larger fraction of axion dark matter occupies interminihalo space, potentially increasing the local axion density and improving haloscope detection prospects. This work highlights the significance of detailed modeling of stellar disruptions in shaping the axion dark matter distribution.

We determine the chiral vortical conductivities, as well as the orbital and spin moment of inertia of a charged, chiral, and rigidly rotating free Fermi gas. To this purpose, we begin by calculating the vacuum expectation values of a vector and axial vector current using the free fermion propagator in this medium. This propagator is derived by employing the Fock-Schwinger method based on the solutions of the Dirac equation in the presence of rotation and finite axial chemical potential. We present a complete derivation of these solutions. We demonstrate that in the first approximation, the chiral vortical conductivity associated with the vector current is proportional to the product of the vector and axial chemical potentials. In contrast, the chiral vortical conductivity related to the axial vector current depends on the temperature, the vector, and the axial vector chemical potential squares. We use the relation between the axial vector current and the angular momentum density associated with spin to determine the spin and the orbital moment of inertia of a rigidly rotating Fermi gas in a charged and chirally imbalanced medium separately. In addition, we compute the total moment of inertia by utilizing the methods presented in the first part of the paper and show that the orbital moment of inertia of a free fermion gas vanishes.

In this paper, we present a novel method for pile-up removal of $pp$ interactions using variational inference with diffusion models, called vipr. Instead of using classification methods to identify which particles are from the primary collision, a generative model is trained to predict the constituents of the hard-scatter particle jets with pile-up removed. This results in an estimate of the full posterior over hard-scatter jet constituents, which has not yet been explored in the context of pile-up removal, yielding a clear advantage over existing methods especially in the presence of imperfect detector efficiency. We evaluate the performance of vipr in a sample of jets from simulated $t\overline{t}$ events overlain with pile-up contamination. vipr outperforms softdrop and has comparable performance to puppiml in predicting the substructure of the hard-scatter jets over a wide range of pile-up scenarios.

We present a comprehensive theoretical framework describing single pion resonant production through inelastic dark fermion-nucleon interactions mediated by resonances in the GeV-scale regime. Building upon the Rein-Sehgal approach, we derive differential cross sections for processes in which an incoming dark fermion scatters off a nucleon, exciting a resonance that subsequently decays into a nucleon and a pion. Our formulation accommodates various mediator types—namely, dark photons with vector and axial couplings, as well as scalar and pseudoscalar mediators—thereby extending the conventional approach that Rein, Sehgal, and Berger performed for neutrino interactions. Transition amplitudes for the nucleon-to-resonance conversion are computed using the relativistic harmonic-oscillator quark model from Feynman, Kislinger, and Ravndal, while a Breit-Wigner prescription is employed to incorporate finite resonance widths. This framework offers a useful tool for interpreting experimental data in dark sector and dark matter searches and represents a contribution to elucidate the possible role of resonances in GeV-scale phenomenology.

We introduce a class of multi-Higgs doublet extensions of the Standard Model that solve the strong $CP$ problem with profound consequences for the flavor sector. The Yukawa matrices are constrained to have many zero entries by a “Higgs-flavor” symmetry, $G_{\mathrm{HF}}$, that acts on Higgs and quark fields. The violation of both $CP$ and $G_{\mathrm{HF}}$ occurs in the Higgs mass matrix so that, for certain choices of $G_{\mathrm{HF}}$ charges, the strong $CP$ parameter $\overline{\theta }$ is zero at tree level. Radiative corrections to $\overline{\theta }$ are computed in this class of theories. They vanish in realistic two-Higgs doublet models with $G_{\mathrm{HF}}={\mathbb{Z}}_3$. We also construct realistic three-Higgs models with $G_{\mathrm{HF}}=\mathrm{U}(1)$, where the one-loop results for $\overline{\theta }$ are model-dependent. Requiring $\overline{\theta }<{10}^{-10}$ has important implications for the flavor problem by constraining the Yukawa coupling and Higgs mass matrices. Contributions to $\overline{\theta }$ from higher-dimension operators are computed at one loop and can also be sufficiently small, although the hierarchy problem of this class of theories is worse than in the Standard Model.