We study a simple extension of the Standard Model featuring a dark sector with an ultralight pseudo-Nambu-Goldstone boson as a dark matter candidate. We focus on the mass range $\mathcal{O}({10}^{-20}–{10}^{-10})\mathrm{eV}$, relevant for strong gravity applications, and explore its production and evolution in the early Universe. The model is formulated in such a way that dark matter does not couple directly to photons or other Standard Model particles avoiding some of the most stringent cosmological bounds related to axionlike particles. In this work, two different scenarios are considered depending on whether dark matter is produced in a preinflationary or postinflationary regime. We also discuss the effect from emergent topological defects such as cosmic strings and domain walls and estimate the spectrum of stochastic gravitational waves produced by their decay, enabling us to test the model at current and future gravitational-wave experiments.

We study the constraints on low-energy coefficients of the $\nu \mathrm{SMEFT}$ generalization of the Standard Model effective theory in the simple case of a $\mathrm{U}(1{)}^{\prime }$ enlargement of the Standard Model gauge group. In particular, we analyze the constraints imposed by the requirement that the extended theory remains free of gauge anomalies. We present the cases of explicit realizations, showing the obtained correlations among the coefficients of $d=6$ operators.

Optically dense clouds in the interstellar medium composed predominantly of molecular hydrogen, known as molecular clouds, are sensitive to energy injection in the form of photon absorption, cosmic-ray scattering, and dark matter (DM) scattering. The ionization rates in dense molecular clouds are heavily constrained by observations of abundances of various molecular tracers. Recent studies have set constraints on the DM-electron scattering cross section using measurements of ionization rates in dense molecular clouds. Here we calculate the analogous bounds on the DM-proton cross section using the molecular Migdal effect, recently adapted from the neutron scattering literature to the DM context. These bounds may be the strongest limits on a strongly coupled DM subfraction, and represent the first application of the Migdal effect to astrophysical systems.

We have studied neutrino phenomenology in the supersymmetric type-I seesaw model endowed with the ${\mathrm{\Gamma }}_2\simeq S_3$ modular symmetry. We have identified different realizations of the $S_3$ modular symmetry, referred to as models A, B, C, and D. The four models are compatible with neutrino mass being inverted ordering (IO). Moreover, models A, B, and D can also accommodate normal ordering (NO) neutrino masses. We identify parameter space for each model compatible with neutrino oscillation at the $2\text{−}\sigma$ level. We then proceed to study the neutrino phenomenology of each model. We find that the lightest neutrino mass can be as light as 0.64 meV in the case of NO in model A and 50 meV in the case of IO in model D. The smallest effective electron neutrino mass attainable in our analysis is 8.8 meV in the case of NO (model A) and 50 meV for IO (model D). Finally, we note that the effective Majorana mass can be as small as 0.33 meV in the case of NO (model A) and 22 meV for IO (model D).

We explore the potential application of quantum computers to the examination of lattice holography, which extends to the strongly coupled bulk theory regime. With adiabatic evolution, we compute the ground state of a spin system on a ($2+1$)-dimensional hyperbolic lattice, and measure the spin-spin correlation function on the boundary. Notably, we observe that with achievable resources for coming quantum devices, the correlation function demonstrates an approximate scale-invariant behavior, aligning with the pivotal theoretical predictions of the anti–de Sitter/conformal field theory correspondence.

We present a lattice QCD study of the elastic $S$-wave $D\overline{B}$ scattering in search of tetraquark candidates with explicitly exotic flavor content $bc\overline{u}\overline{d}$ in the isospin $I=0$ and $J^P=0^{+}$ channel. We use four lattice QCD ensembles with dynamical $u/d$, $s$, and $c$ quark fields generated by the MILC collaboration. A nonrelativistic QCD Hamiltonian, including improvement coefficients up to $\mathcal{O}({\alpha }_s{v}^4)$, is utilized for the bottom quarks. For the rest of the valence quarks we employ a relativistic overlap action. Five different valence quark masses are utilized to study the light quark mass dependence of the $D\overline{B}$ scattering amplitude. The finite volume energy spectra are extracted following a variational approach. The elastic $D\overline{B}$ scattering amplitudes are extracted employing Lüscher’s prescription. The light quark mass dependence of the continuum extrapolated amplitudes suggests an attractive interaction between the $\overline{B}$ and $D$ mesons. At the physical pseudoscalar meson mass ($M_{ps}=M_{\pi }$) the $D\overline{B}$ scattering amplitude has a subthreshold pole corresponding to a binding energy of $-39{(}_{-6}^{+4}){(}_{-18}^{+8})\mathrm{MeV}$ with respect to the $D\overline{B}$ threshold. The critical $M_{ps}$ at which the $D\overline{B}$ scattering length diverges and the system becomes unbound corresponds to $M_{ps}^{*}=2.94(15)(5)\mathrm{GeV}$. This result can hold significant experimental relevance in the search for a bound scalar $T_{bc}$ tetraquark, which could well be the next “doubly heavy” bound tetraquark to be discovered with only weak decay modes.

Motivated by one-dimensional color-electric flux-tube formation in four-dimensional (4D) QCD, we investigate a possibility of effective dimensional reduction in the 4D Yang-Mills (YM) theory. We propose a new gauge fixing of “dimensional reduction (DR) gauge” defined so as to minimize $R_{\mathrm{DR}}\equiv \int d^{4}s\mathrm{Tr}[A_x^2(s)+A_y^2(s)]$, which has a residual gauge symmetry for the gauge function $\mathrm{\Omega }(t,z)$ like 2D QCD on the $t\text{−}z$ plane. We investigate effective dimensional reduction in the DR gauge using SU(3) quenched lattice QCD at $\beta =6.0$. The amplitude of $A_x(s)$ and $A_y(s)$ are found to be strongly suppressed in the DR gauge. We consider “$tz$-projection” of $A_{x,y}(s)\to 0$ for the gauge configuration generated in the DR gauge, in a similar sense to Abelian projection in the maximally Abelian gauge. By the $tz$-projection in the DR gauge, the interquark potential is not changed, and $A_t(s)$ and $A_z(s)$ play a dominant role in quark confinement. In the DR gauge, we calculate a spatial correlation $⟨\mathrm{Tr}{A}_{\perp }(s)A_{\perp }(s+r{a}_{\perp })⟩(\perp =x,y)$ and estimate the spatial mass of $A_{\perp }(s)(\perp =x,y)$ as $M\simeq 1.7\mathrm{GeV}$. It is conjectured that this large mass makes $A_{\perp }(s)$ inactive and realizes the dominance of $A_t(s)$ and $A_z(s)$ in infrared region in the DR gauge. We also calculate the spatial correlation of two temporal link-variables and find that the correlation decreases as $\exp (-mr)$ with $m\simeq 0.6\mathrm{GeV}$. Using a crude approximation, the 4D YM theory is reduced into an ensemble of 2D YM systems with the coupling of $g_{2\mathrm{D}}=gm$.

We use the higher-order tensor renormalization group method to study the two-dimensional generalized XY model that admits integer and half-integer vortices. This model is the deformation of the classical XY model and has a rich phase structure consisting of nematic, ferromagnetic, and disordered phases and three transition lines belonging to the Berezinskii-Kosterlitz-Thouless and Ising class. We explore the model for a wide range of temperatures, $T$, and the deformation parameter, $\mathrm{\Delta }$, and compute specific heat along with integer and half-integer magnetic susceptibility, finding both Berezinskii-Kosterlitz-Thouless-like and Ising-like transitions and the region where they meet.

We present a first study of the effects of renormalization-group resummation (RGR) and leading-renormalon resummation (LRR) on the systematic errors of the unpolarized isovector nucleon generalized parton distribution in the framework of large-momentum effective theory. This work is done using lattice gauge ensembles generated by the MILC Collaboration, consisting of $2+1+1$ flavors of highly improved staggered quarks with a physical pion mass at lattice spacing $a\approx 0.09\mathrm{fm}$ and a box width $L\approx 5.76\mathrm{fm}$. We present results for the nucleon $H$ and $E$ generalized parton distributions (GPDs) with average boost momentum $P_z\approx 2\mathrm{GeV}$ at momentum transfers $Q^2=[0,0.97]{\mathrm{GeV}}^2$ at skewness $\xi =0$ as well as $Q^2\in 0.23{\mathrm{GeV}}^2$ at $\xi =0.1$, renormalized in the modified minimal subtraction ($\overline{\mathrm{MS}}$) scheme at scale $\mu =2.0\mathrm{GeV}$, with two- and one-loop matching, respectively. We demonstrate that the simultaneous application of RGR and LRR significantly reduces the systematic errors in renormalized matrix elements and distributions for both the zero and nonzero skewness GPDs, and that it is necessary to include both RGR and LRR at higher orders in the matching and renormalization processes.

In many calculations involving polarized twist-2 parton densities to higher order in the strong coupling constant one uses the Larin scheme to describe chiral effects in dimensional regularization. Upon forming observables, the scheme dependence cancels. Still one needs a corresponding regularization scheme to compute the contributing building blocks, like massless and massive Wilson coefficients, as well as the massive three-loop operator matrix elements used in the variable flavor number scheme. These are matched to the evolved parton distribution functions in the Larin scheme. Starting with suitable input distributions we provide the solution of scale evolution of the different polarized parton distribution functions in Bjorken $x$ space for a wide range of virtualities $Q^2$ in the Larin scheme, at next-to-leading, at next-to-next-to-leading order for the first time. We also illustrate the deviation between the parton distributions in the Larin and $\overline{\mathrm{MS}}$ schemes numerically.

To continue from our previous work [Phys. Rev. D 109, 073007 (2024)], we derive the full Standard Model prediction of the most general free neutron differential decay rate with all massive particles (neutron, proton, and electron) polarized, including the $\mathcal{O}(1/m_N)$ recoil corrections and $\mathcal{O}(\alpha /\pi )$ radiative corrections. For the latter we adopt the newly developed pseudoneutrino formalism which is compatible to realistic experimental setups, in which neutrinos and photons are not detected. We also provide readily executable Mathematica notebooks to evaluate these corrections.

Liquid argon time projection chamber (LArTPC) detector technology offers a wealth of high-resolution information on particle interactions, and leveraging that information to its full potential requires sophisticated automated reconstruction techniques. This article describes nugraph2, a graph neural network for low-level reconstruction of simulated neutrino interactions in a LArTPC detector. Simulated neutrino interactions in the MicroBooNE detector geometry are described as heterogeneous graphs, with energy depositions on each detector plane forming nodes on planar subgraphs. The network utilizes a multihead attention message-passing mechanism to perform background filtering and semantic labeling on these graph nodes, identifying those associated with the primary physics interaction with 98.0% efficiency and labeling them according to particle type with 94.9% efficiency. The network operates directly on detector observables across multiple two-dimensional representations but utilizes a three-dimensional-context-aware mechanism to encourage consistency between these representations. Model inference takes $0.12\mathrm{s}/\mathrm{event}$ on a CPU and $0.005\mathrm{s}/\mathrm{event}$ batched on a GPU. This architecture is designed to be a general-purpose solution for particle reconstruction in neutrino physics, with the potential for deployment across a broad range of detector technologies, and offers a core convolution engine that can be leveraged for a variety of tasks beyond the two described in this paper.

A search for long-lived particles (LLPs) decaying in the CMS muon detectors is presented. A data sample of proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$, recorded at the LHC in 2016–2018, is used. The decays of LLPs are reconstructed as high multiplicity clusters of hits in the muon detectors. In the context of twin Higgs models, the search is sensitive to LLP masses from 0.4 to 55 GeV and a broad range of LLP decay modes, including decays to hadrons, $\tau$ leptons, electrons, or photons. No excess of events above the standard model background is observed. The most stringent limits to date from LHC data are set on the branching fraction of the Higgs boson decay to a pair of LLPs with masses below 10 GeV. This search also provides the best limits for various intervals of LLP proper decay length and mass. Finally, this search sets the first limits at the LHC on a dark quantum chromodynamic sector whose particles couple to the Higgs boson through gluon, Higgs boson, photon, vector, and dark-photon portals, and is sensitive to branching fractions of the Higgs boson to dark quarks as low as $2\times {10}^{-3}$.

With the data samples taken at center-of-mass energies from 2.00 to 3.08 GeV with the BESIII detector at the BEPCII collider, a partial wave analysis on the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0$ process is performed. The Born cross sections for $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0$ and its intermediate processes $e^{+}{e}^{-}\to \rho \pi$ and $\rho (1450)\pi$ are measured as functions of $\sqrt{s}$. The results for $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0$ are consistent with previous results measured with the initial state radiation method within one standard deviation, and improve the uncertainty by a factor of ten. By fitting the line shapes of the Born cross sections for the $e^{+}{e}^{-}\to \rho \pi$ and $e^{+}{e}^{-}\to \rho (1450)\pi$, a structure with mass $M=2119\pm 11\pm 15\mathrm{MeV}/c^2$ and width $\mathrm{\Gamma }=69\pm 30\pm 5\mathrm{MeV}$ is observed with a significance of $5.9\sigma$, where the first uncertainties are statistical and the second ones are systematic. This structure can be interpreted as an excited $\omega$ state.

We study interacting theories of $N$ left-moving and $\overline{N}$ right-moving Floreanini-Jackiw bosons in two dimensions. A parametrized family of such theories is shown to enjoy (nonmanifest) Lorentz invariance if and only if its Lagrangian obeys a flow equation driven by a function of the energy-momentum tensor. We discuss the canonical quantization of such theories along classical stress tensor flows, focusing on the case of the root-$T\overline{T}$ deformation, where we obtain perturbative results for the deformed spectrum in a certain large-momentum limit. In the special case $N=\overline{N}$, we consider the quantum effective action for the root-$T\overline{T}$-deformed theory by expanding around a general classical background, and we find that the one-loop contribution vanishes for backgrounds with constant scalar gradients. Our analysis can also be interpreted via dual $U(1)$ Chern-Simons theories in three dimensions, which might be used to describe deformations of charged ${\mathrm{AdS}}_3$ black holes or quantum Hall systems.

We consider rotational holographic transport in strongly coupled $2+1$-dimensional systems, from the point of view of $3+1$-dimensional gravity. We consider the moment of inertia $I$ as a kind of transport coefficient, identified with the moment of inertia of a charged rotating black hole in ${\mathrm{AdS}}_4$ background. In the low-temperature region, we find the behavior of the density $I/A$ with temperature $T$ and angular velocity $\mathrm{\Omega }$ and find a quadratic behavior for $\partial (I/A)/\partial \mathrm{\Omega }$ with $T$, in the presence of some charge $Q$.

Considering a doubly holographic model, we study the black hole information paradox for the eternal ${\mathrm{AdS}}_d$-RN black hole coupled to and in equilibrium with a $d$-dimensional conformal bath whose state has been deformed by the charged scalar field coupled to a U(1) gauge field. Without a brane, the spontaneous symmetry breaking of the gauge field on boundary systems can induce a second-order phase transition of the charged scalar field at the critical temperature, known as holographic superconductors. The bath deformation can significantly change its entanglement dynamics with the black hole, resulting in variations in the Page curve and Page time. Our results indicate that characteristic parameters of the Page curve, such as entanglement velocity, initial area difference and Page time, can be used as suitable probes to detect superconducting phase transitions. In particular, the entanglement velocity can also probe both Kasner flows and Josephson oscillations. When keeping the endpoint of the radiation region fixed at twice the critical Page point, the entanglement velocity (the internal backreaction) has a more significant influence on the Page time compared to the initial area difference (the external backreaction).

Lagrangian formulation for perfect fluid equations which hold invariant under the $\ell$-conformal Galilei group with half-integer $\ell$ is proposed. It is based on a Clebsch-type parametrization and reproduces Lagrangian description of the Euler fluid equations for $\ell =\frac{1}{2}$. The transition from the Lagrangian formulation to the Hamiltonian one is analyzed in detail.

Recently Danielson, Satishchandran, and Wald (DSW) have shown that quantum superpositions held outside of Killing horizons will decohere at a steady rate. This occurs because of the inevitable radiation of soft photons (gravitons), which imprint a electromagnetic (gravitational) “which-path” memory onto the horizon. Rather than appealing to this global description, an experimenter ought to also have a local description for the cause of decoherence. One might intuitively guess that this is just the bombardment of Hawking/Unruh radiation on the system, however simple calculations challenge this idea—the same superposition held in a finite temperature inertial laboratory does not decohere at the DSW rate. In this work we provide a local description of the decoherence by mapping the DSW setup onto a worldline-localized model resembling an Unruh-DeWitt particle detector. We present an interpretation in terms of random local forces which do not sufficiently self-average over long times. Using the Rindler horizon as a concrete example we clarify the crucial role of temperature, and show that the Unruh effect is the only quantum mechanical effect underlying these random forces. A general lesson is that for an environment which induces Ohmic friction on the central system (as one gets from the classical Abraham-Lorentz-Dirac force, in an accelerating frame) the fluctuation-dissipation theorem implies that when this environment is at finite temperature it will cause steady decoherence on the central system. Our results agree with DSW and provide the complementary local perspective.

We consider two-component Bose-Einstein condensates (BECs) and introduce the BEC vortex in $1+2$ dimensions. We focus on two types of gapped excitations induced by the modes of two-component BECs with relative phases of 0 and $\pi$, analogous to the massive scalar field with positive and negative mass squared, respectively. The inclusion of space-dependent Rabi coupling can induce an effective space-dependent mass term. We study superradiant instabilities resulting from the quasibound states corresponding to positive mass squared and the tachyonic instabilities arising from negative mass squared in both the frequency and time domains. These instabilities resemble two possible mechanisms that make Kerr black holes unstable in scalar-tensor gravity with the presence of matter around the black hole. Our proposed phenomena could potentially be implemented in future experiments, drawing from the success of recent analog rotating black hole implementations.