We determine the nucleon axial, scalar, and tensor charges and the nucleon $\sigma$-terms using twisted mass fermions. We employ three ensembles with approximately equal physical volume of about 5.5 fm, three values of the lattice spacing, approximately 0.06, 0.07, and 0.08 fm, and with the mass of the degenerate up and down, strange and charm quarks tuned to approximately their physical values. We compute both isovector and isoscalar charges and $\sigma$-terms and their flavor decomposition including the disconnected contributions. We use the Akaike information criterion to evaluate systematic errors due to excited states and the continuum extrapolation. For the nucleon isovector axial charge we find $g_A^{u-d}=1.250(24)$, in agreement with the experimental value. Moreover, we extract the nucleon $\sigma$-terms and find for the light quark content ${\sigma }_{\pi N}=41.9(8.1)\mathrm{MeV}$ and for the strange ${\sigma }_s=30(17)\mathrm{MeV}$.

In the present study, we explore the properties of generalized parton distributions (GPDs) for the kaon and pion within the framework of the nonlocal chiral quark model ($\mathrm{NL}\chi \mathrm{QM}$). Valence quark GPDs of the kaon and pion are analyzed with respect to their momentum fraction $x$ and skewness $\xi$ dependencies in the DGLAP (Dokshitzer-Gribov-Lipatov-Altarelli-Parisi) and ERBL (Efremov-Radyushkin-Brodsky-Lepage) regions. We observe that the asymmetry of the current quark masses in kaon results in a significant distortion of the quark GPDs in kaon near $\xi =1$, compared to the case of the pion. The quark GPDs of the kaon and pion are evolved to ${\mu }^2=4{\mathrm{GeV}}^2$ and $100{\mathrm{GeV}}^2$ by the QCD evolution equation at one-loop order using the apfel++ package. We find that the produced sea quarks and gluons are largely suppressed as $\xi$ becomes nonzero, predominantly confined within the ERBL region. We subsequently examine the polynomiality of the GPDs and numerically obtain the electromagnetic and gravitational form factors of the kaon and pion. For the kaon, gravitational form factor ratios $A_{\overline{s}/K^{+}}(0)/A_{s/K^{+}}(0)=1.26$ and $D_{\overline{s}/K^{+}}(0)/D_{s/K^{+}}(0)=1.10$ are reported and compared with results from the recent lattice QCD calculations and other effective models.

We compute the fragmentation function of a light quark into S-wave fully charmed tetraquarks ($T_{4c}$) within the nonrelativistic QCD framework, at leading order in ${\alpha }_s$ and $v$. We present results for light quark fragmentation into $T_{4c}$ and predict its contribution to $T_{4c}$ production at high transverse momentum ($p_T$) at the large hadron collider and electron-ion collider. We also compare light quark fragmentation with charm quark and gluon fragmentation channels. Our analysis shows that the production cross section for $T_{4c}$ from light quark fragmentation is smaller than that from gluon fragmentation but larger than that from charm quark fragmentation.

The recent development of the field correlator method (FCM) is discussed, with applications to the most interesting areas of QCD physics obtained in the lattice data and experiment. These areas include: (a) the connection of colorelectric (CE) confinement with the basic quark and gluon condensates; (b) the explicit form of the colorelectric deconfinement at a growing temperature $T$; (c) the theory of the colormagnetic (CM) confinement at all temperatures; (d) the theory of strong decays, the theory of parton distribution function (PDF), and jets in the instantaneous formalism with confinement. We demonstrate that the field correlator method with instantaneous formalism and confinement (instead of the light cone formalism and pure perturbation theory) can provide the way to the theory of QCD, which helps to describe world data without phenomenological parameters.

Using a data sample of $(10087\pm 44)\times {10}^6$ $J/\psi$ events collected with the BESIII detector, we search for the decays $\eta /{\eta }^{\prime }\to e^{+}{e}^{-}{\mu }^{+}{\mu }^{-}$ and ${\eta }^{\prime }\to {\mu }^{+}{\mu }^{-}{\mu }^{+}{\mu }^{-}$ via the radiative decays $J/\psi \to \gamma \eta /\gamma {\eta }^{\prime }$. No excess of events over expected background is observed for any of the decays of interest. At 90% confidence level, we report the first upper limits on the branching fractions of ${\eta }^{\prime }\to e^{+}{e}^{-}{\mu }^{+}{\mu }^{-}$ and ${\eta }^{\prime }\to {\mu }^{+}{\mu }^{-}{\mu }^{+}{\mu }^{-}$ to be $1.75\times {10}^{-6}$ and $5.28\times {10}^{-7}$, respectively. In addition, we set an upper limit on the branching fraction of $\eta \to e^{+}{e}^{-}{\mu }^{+}{\mu }^{-}$ to be $6.88\times {10}^{-6}$, which improves the previous result by about two orders of magnitude.

The $\gamma$-ray emission originating from in-flight annihilation (IA) of positrons is a powerful observable for constraining high-energy positron production from exotic sources. By comparing diffuse $\gamma$-ray observations of INTEGRAL, COMPTEL, and EGRET to theoretical predictions, we set the most stringent constraints on electrophilic feebly interacting particles, thereby proving IA as a valuable probe of new physics. In particular, we extensively discuss the case of MeV-scale sterile neutrinos, where IA sets the most stringent constraints, excluding $|U_{\mu 4}{|}^2\gtrsim {10}^{-13}$ and $|U_{\tau 4}{|}^2\gtrsim 2\times {10}^{-13}$ for sterile neutrinos mixed with $\mu$ and $\tau$ neutrinos, respectively. These constraints improve existing limits by more than an order of magnitude. We briefly discuss the application of these results to a host of exotic positron sources such as dark photons, axionlike particles, primordial black holes, and sub-GeV dark matter.

We investigate various properties of extremal dyonic static black holes in Einstein-Maxwell-Dilaton-Axion theory. We obtain a simple first-order ordinary differential equation for the black hole mass in terms of its electric and magnetic charges, which we can solve explicitly for certain special values of the scalar couplings. For one such case we also construct new dyonic black hole solutions, making use of the presence of an enhanced $SL(2,\mathbb{R})$ symmetry. Finally, we investigate the structure of long range forces and binding energies between nonequivalent extremal black holes. For certain special cases, we can identify regions of parameter space where the force is always attractive or repulsive. Unlike in the case without an axion, the force and binding energies between distinct black holes are not always correlated with each other. Our work is motivated in part by the question of whether long range forces between nonidentical states can potentially encode information about UV constraints on low-energy physics.

The entanglement entropy of a massless scalar field in de Sitter space depends on multiple scales, such as the radius of the entangling surface, the Hubble constant and the UV cutoff. We perform a high-precision numerical calculation using a lattice model in order to determine the dependence on these scales in the Bunch-Davies vacuum. We derive the leading de Sitter corrections to the flat-space entanglement entropy for subhorizon entangling radii. We analyze the structure of the finite-size effects and show that the contribution to the entanglement entropy of the sector of the theory with vanishing angular momentum depends logarithmically on the size of the overall system, which extends beyond the horizon.

This work constitutes the second part of a series of studies that aim to utilize tools from Hamiltonian mechanics to investigate the motion of an extended body in general relativity. The first part of this work [On the integrability of extended test body dynamics around black holes, Classical Quantum Gravity.] established the ten-dimensional, covariant Hamiltonian framework, incorporating all quadratic-in-spin corrections from the secondary spin to the geodesic motion in arbitrary spacetime. Notably, this framework yields an integrable Hamiltonian system (up to quadratic terms in spin) when both the background spacetime and secondary compact objects are rotating Kerr black holes. The present work translates this abstract integrability result into tangible applications for linear-in-spin Hamiltonian dynamics of a compact object in a Schwarzschild spacetime. In particular, a canonical system of coordinates is constructed explicitly, which exploits the spherical symmetry of the Schwarzschild spacetime. These coordinates are based on a relativistic generalization of the classical Andoyer variables of Newtonian rigid body motion. This canonical setup allows us to derive ready-to-use formulas for action-angle coordinates and gauge-invariant Hamiltonian frequencies, which automatically include all linear-in-spin effects. No external parameters or ad hoc choices are necessary, and the framework can be used to find complete solutions by quadrature of generic (bound or unbound), linear-in-spin orbits, including orbital inclination, precession and eccentricity, as well as spin precession. The efficacy of the formalism is demonstrated here in the context of circular orbits with arbitrary spin and orbital precession, with the results validated against known results in the literature.

We investigate the (axial) quasinormal modes of black holes embedded in generic matter profiles. Our results reveal that the axial quasinormal modes experience a redshift when the black hole is surrounded by various matter environments, proportional to the compactness of the matter halo. Our calculations demonstrate that for static black holes embedded in galactic matter distributions, there exists a universal relation between the matter environment and the redshifted vacuum quasinormal modes. In particular, for dilute environments the leading order effect is a redshift $1+U$ of frequencies and damping times, with $U\sim -\mathcal{C}$ the Newtonian potential of the environment at its center, which scales with its compactness $\mathcal{C}$.

Decaying dark matter (DDM) can be tested via different astrophysical and cosmological probes. In particular, particles in the $\sim 9.5–30\mathrm{eV}$ mass range that decay into monochromatic photons, would contribute to the extragalactic background light (EBL) in the ultraviolet (UV) bandwidth. In this work, we show that an intriguing improvement to the constraints on such DDM models can come from broadband UV surveys, such as GALEX or the upcoming ULTRASAT satellite. These provide diffuse light maps of the UV-EBL, integrated over a wide redshift range. The cross correlation between intensity fluctuations in these maps with a reference spectroscopic galaxy survey, can be used to reconstruct the redshift evolution of the EBL intensity; in this way, it is also possible to detect signatures of contributions from DDM. We forecast the constraining power of $(\mathrm{GALEX}+\mathrm{ULTRASAT})\times \mathrm{DESI}$, and we show they will be able to detect DDM with decay rate up to $\mathcal{O}({10}^{-26}\mathrm{s})$. In the context of axionlike particles (ALP), our forecasts can be converted to constraints on the ALP-photon coupling; our results show this technique will test ALP with coupling $\lesssim \mathcal{O}({10}^{-12}{\mathrm{GeV}}^{-1})$, more than an order of magnitude better than current bounds in this mass range.

We propose a self-supervised learning model to denoise gravitational wave (GW) signals in the time series strain data without relying on waveform information. Denoising GW data is a crucial intermediate process for machine-learning-based data analysis techniques, as it can simplify the model for downstream tasks such as detections and parameter estimations. We use the blind-spot neural network and train it with whitened strain data with GW signals injected as both input data and target. Under the assumption of a Gaussian noise model, our model successfully denoises over 90% of GW signals from binary black hole (BBH) and neutron star–black hole mergers when the signal-to-noise ratio (SNR) is larger than 13 and 16 and denoises over 50% of binary neutron star signals when the SNR is larger than 23, with an overlap greater than 0.2, over which the denoised signal can have visually distinguishable patterns. Our model also denoises over 90% of BBH signals in H1, L1, and V1 data detected in the O1, O2, and O3 observation runs when the network SNR is larger than 11, 12, and 20, respectively. We also test the model’s potential to extract glitch features, loud inspiral compact binary coalescence signals a few seconds before the merger, and unseen core-collapse supernova signals during training.

Stasis is a unique cosmological phenomenon in which the abundances of different energy components in the universe (such as matter, radiation, and vacuum energy) each remain fixed even though they scale differently under cosmological expansion. Moreover, extended epochs exhibiting stasis are generally cosmological attractors in many beyond the Standard Model (BSM) settings and thus arise naturally and without fine-tuning. To date, stasis has been found within a number of very different BSM cosmologies. In some cases, stasis emerges from theories that contain large towers of decaying states (such as theories involving extra dimensions or string theory). By contrast, in other cases, no towers of states are needed, and stasis instead emerges due to thermal effects involving particle annihilation rather than decay. In this paper, we study the dynamics of the energy flows in all of these theories during stasis and find that these theories all share a common energy-flow structure which in some sense lies between particle decay and particle annihilation. This structure has been hidden until now but ultimately lies at the root of the stasis phenomenon, with all of the previous stases appearing as different manifestations of this common underlying structure. This insight not only allows us to understand the emergence of stasis in each of these different scenarios, but also provides an important guide for the potential future discovery of stasis in additional cosmological systems.

Primordial black holes (PBHs), possibly constituting a non-negligible fraction of dark matter (DM), might be responsible for a number of gravitational-wave events detected by LIGO/Virgo/KAGRA. In this paper, we simulate the evolution of PBH binaries in DM halos and calculate their merger rate up to redshift of 10. We assume that DM halos are made entirely by a combination of single PBHs and PBH binaries. We present the resulting merger rates from the two main channels that lead to merging PBH binaries: two-body captures and binary-single interactions. We account for alternative assumptions on the dark matter halo mass-concentration relationship versus redshift. We also study what impact the PBH mass distribution, centered in the stellar-mass range, has on the PBH merger rate that the ground-based gravitational-wave observatories can probe. We find that, under reasonable assumptions on the abundance of PBH binaries relative to single PBHs, the binary-single interaction rates can be dominant over the two-body capture channel. Our work studies in detail the dynamics of PBHs inside DM halos, advancing our understanding on how the current gravitational-wave events constrain the properties of PBHs. Moreover, we make predictions in a redshift range to be probed by future observatories.

Direct detection of light dark matter can be significantly enhanced by upscattering of dark matter with energetic particles in the cosmic ambient. This boosted dark matter flux can reach kinetic energies up to tens of MeV, while the typical kinetic energies of GeV mass dark matter particles in the Milky Way halo are of the order of keV. Dark matter boosted by energetic diffuse supernova background neutrinos can be detected only through nuclear or electron scattering in ground-based detectors requiring a nonzero interaction of dark matter with nucleon or electron, in addition to its interaction with neutrino. However, in the presence of dark matter-nucleon (electron) interaction, the scattering of dark matter with cosmic rays is unavoidable. Thus, we consider boosted dark matter resulting from diffuse supernova neutrinos as well as cosmic protons (electrons) considering both energy-dependent and energy-independent scattering cross sections between dark matter and standard model particles. We explore this scenario in dark matter detectors such as XENONnT and neutrino detectors like Super-Kamiokande.

We introduce a systematic method to derive the effective action for domain walls directly from the scalar field theory that gives rise to their solitonic solutions. The effective action for the Goldstone mode, which characterizes the soliton’s position, is shown to consist of the Nambu-Goto action supplemented by higher-order curvature invariants associated to its worldvolume metric. Our approach constrains the corrections to a finite set of Galileon terms, specifying both their functional forms and the procedure to compute their coefficients. We do a collection of tests across various models in $2+1$ and $3+1$ dimensions that confirm the validity of this framework. Additionally, the method is extended to include bound scalar fields living on the world sheet, along with their couplings to the Goldstone mode. These interactions reveal a universal nonminimal coupling of these scalar fields to the Ricci scalar on the world sheet. A significant consequence of this coupling is the emergence of a parametric instability, driven by interactions between the bound states and the Goldstone mode.

We present a novel relaxation time approximation for kinetic theory with spin which takes into account the nonlocality of particle collisions. In particular, it models the property of the microscopic nonlocal collision term to vanish in global, but not in local equilibrium. We study the asymptotic distribution function obtained as the solution of the Boltzmann equation within the nonlocal relaxation time approximation in the limit of small gradients and short relaxation time. We show that the resulting polarization agrees with the one obtained from the Zubarev formalism for a certain value of a coefficient that determines the timescale on which orbital angular momentum is converted into spin. This coefficient can be identified with a parameter related to the pseudogauge choice in the Zubarev formalism. Finally, we demonstrate how the nonlocal collision term generates polarization from vorticity by studying a nonrelativistic rotating cylinder both from kinetic and hydrodynamic approaches, which are shown to be equivalent in this example.

We analyze the spin alignment of vector mesons stemming from spin correlation of the quark and antiquark induced by background color fields in relativistic heavy ion collisions. The quark-coalescence equation relating the collision kernel of the vector-meson kinetic equation to spin alignment is expanded to the relativistic case. Focusing on the color-octet contribution, the spin alignment for $\varphi$ mesons from glasma fields with momentum dependence is investigated, where the scenarios for different spin quantization axes are considered. Moreover, we qualitatively analyze the spin alignment from isotropic color fields in the quark gluon plasma phase for comparison. In particular, we propose that the experimental measurement of spin alignment along the beam direction, dubbed as the longitudinal spin alignment, could be useful to identify the dominance of longitudinal spin correlation potentially led by the glasma effect in high-energy nuclear collisions.

When building dark matter (DM) models, one often imposes conserved discrete symmetries to stabilize DM candidates. The simplest choice is ${\mathbb{Z}}_2$ but models with larger stabilizing groups have also been explored. Can a conserved non-Abelian group lead to a viable DM model? Here, we address this question within the three-Higgs-doublet model based on the group $\mathrm{\Sigma }(36)$, in which DM stabilization by a non-Abelian group is not only possible but inevitable. We show that the tight connections between the Higgs, fermion, and DM sectors repeatedly drive the model into conflict with the LHC results and DM observations, with the most recent LZ results playing a decisive role. We believe that the lessons learned from this study help chart the limits of what can be achieved within multi-Higgs-doublet DM models with large symmetry groups.

We present the determination of the charm quark mass, the masses, and decay constants of charmed mesons using thirteen $2+1$ flavor gauge ensembles at five different lattice spacings $a\in [0.05,0.11]\mathrm{fm}$, 8 pion masses $m_{\pi }\in (130,360)\mathrm{MeV}$, and several values of the strange quark mass, which allows us to do the chiral and continuum extrapolation. These ensembles are generated through the stout smeared clover fermion action and Symanzik gauge actions with the tadpole improvement. By absorbing the discretization errors into the masses and field normalization of the charm quark, we manage to suppress the discretization error of the charmed meson mass and all the S-wave open charmed meson decay constants to a few percent or even less at lattice spacing $a\sim 0.1\mathrm{fm}$. Moreover, discretization errors for other quantities are also significantly reduced. The continuum extrapolated charm quark mass, $m_c(m_c)=1.2933(72)(95)\mathrm{GeV}$ in $\overline{\mathrm{MS}}$ scheme, is determined using QED-subtracted $D_s$ meson mass and nonperturbative renormalization. Predictions of the open and close charm mesons using this charm quark mass agree with the experimental values at 0.1–0.5% level uncertainty. We obtained $D_{(s)}$ decay constants and also by far the most precise $D_{(s)}^{*}$ decay constants $f_{D^{*}}=0.2292(26)(17)\mathrm{GeV}$ and $f_{D_s^{*}}=0.2691(30)(03)\mathrm{GeV}$.