Recently, the BESIII Collaboration updated the data for the exotic state, $D_{s0}^{*}(2317)$, with a mass of $2318.3\pm 1.2\pm 1.2\mathrm{MeV}$ from the positronium annihilation process. Inspired by the experiment, we systematically investigated the $c\overline{q}$ meson family spectrum from the perspectives of two-quark, four-quark, and mixed two-four-quark structures, including $D_s$, $D_s^{*}$, $D_{s0}^{*}(2317)$, and $D_{s1}(2460)$, with the help of the Gaussian expansion method, which is a very accurate calculation method for few-body systems. We found that with appropriate spin-orbit coupling parameter $a_s$, the chiral quark model can effectively describe both $D_{s0}^{*}(2317)$ and $D_{s1}(2460)$. The four-quark calculation shows that the $DK$ state does not form a bound state, but the effective potential calculation shows an attractive interaction between them. Finally, we performed mixed two-four-quark calculations, and the results, with the help of the unquenched effect, show that the energies of $D_{s0}^{*}(2317)$ and $D_{s1}(2460)$ are in better agreement with experimental values. Therefore, we conclude that these two particles are good candidates for mixed two-four-quark states.

We revisit optimization of functional renormalization group flows by analyzing regularized loop integrals. This leads us to a principle, the principle of strongest singularity, and a corresponding order relation which allows us to order existing regularization schemes with respect to the stability of renormalization group flows. Moreover, the order relation can be used to construct new regulators in a systematic fashion. For studies of critical behavior, which require to follow renormalization group flows down to the deep infrared regime, such new regulators may turn out to be particularly useful. The general application of this principle is demonstrated with the aid of a scalar field theory which is solved over a wide range of scales with novel methods borrowed from numerical fluid dynamics.

If the dark sector possesses long-range self-interactions, these interactions can source dramatic collective instabilities even in astrophysical settings where the collisional mean free path is long. Here, we focus on the specific case of dark matter halos composed of a dark $U(1)$ gauge sector undergoing a dissociative cluster merger. We study this by performing the first dedicated particle-in-cell plasma simulations of interacting dark matter streams, tracking the growth, formation, and saturation of instabilities through both the linear and nonlinear regimes. We find that these instabilities give rise to local (dark) electromagnetic inhomogeneities that serve as scattering sites, inducing an effective dynamic collisional cross section. Mapping this effective cross section onto existing results from large-scale simulations of the Bullet Cluster, we extend the limit on the dark charge-to-mass ratio by over 10 orders of magnitude. Our results serve as a simple example of the rich phenomenology that may arise in a dark sector with long-range interactions and motivate future dedicated study of such “dark plasmas.”

We identify symmetries in a broad class of vectorlike confining dark sectors that forbid the leading electromagnetic moments that would ordinarily mediate dark baryon scattering with the Standard Model. The absence of these operators implies dark baryon dark matter has much smaller cross sections for elastic scattering off nuclei, leading to suppressed direct detection signals. In the confined description, we identify an “$\mathcal{H}$-parity” symmetry that exists in any dark sector with dark quarks transforming under a vectorlike representation of a new confining SU($N_c$) gauge theory as well as a vectorlike representation of the electroweak group ${\mathrm{SU}(2)}_L$. The parity is independent of $N_c$ and $N_f$, though it is essential that the dark quarks are neutral under hypercharge. This parity forbids dark hadron electric and magnetic dipole moments, charge radius, and anapole moment, while permitting dimension-7 operators that include polarizability, electroweak loop-induced interactions, and lower-dimensional electromagnetic transition moments between different neutral dark baryon states. We work out an explicit example, $N_c=N_f=3$, that is the most minimal theory with fermionic dark baryons. In this specific model, we use the nonrelativistic quark model to show the magnetic dipole moment and charge radius vanish, while the transition moments are nonzero, consistent with $\mathcal{H}$-parity. We discuss the implications of a suppressed direct detection signal, emphasizing that this broad class of models provide a well-motivated target for future colliders.

We investigate the thermal phase structure of the Berenstein-Maldacena-Nastase matrix model using nonperturbative lattice Monte Carlo calculations. Our main analyses span 3 orders of magnitude in the coupling, involving systems with sizes up to $N_{\tau }=24$ lattice sites and $\mathrm{SU}(N)$ gauge groups with $8\le N\le 16$. In addition, we carry out extended checks of discretization artifacts for $N_{\tau }\le 128$ and gauge group SU(4). We find results for the deconfinement temperature that interpolate between the perturbative prediction at weak coupling and the large-$N$ dual supergravity calculation at strong coupling. While we confirm that the phase transition is first order for strong coupling, it appears to be continuous for weaker couplings.

Within the framework of nonrelativistic-QCD factorization, we perform a comprehensive investigation of the color singlet (CS) contribution to prompt $J/\psi$ pair production at the CERN Large Hadron Collider at next-to-leading order (NLO) in ${\alpha }_s$. Specifically, we compare our NLO predictions with measurements from the LHCb, CMS, and ATLAS collaborations. We find that the CS contribution itself can well describe the LHCb data in most of the experimental bins, except in the regions where the fixed-order calculation is spoiled by the emission of soft or hard-collinear gluons. In the CMS and ATLAS cases, however, the CS predictions greatly undershoot both the measured total and differential cross sections, despite sizable $K$ factors, of 2–3, for the total cross sections.

We study the $P$-wave single charmed baryons of the $SU(3)$ flavor ${\overline{\mathbf{3}}}_{\mathbf{F}}$ within the framework of heavy quark effective theory. We systematically calculate their strong and radiative decay properties using the light-cone sum rule method. Besides the ${\mathrm{\Lambda }}_c(2595)$, ${\mathrm{\Lambda }}_c(2625)$, ${\mathrm{\Xi }}_c(2790)$, and ${\mathrm{\Xi }}_c(2815)$, our results suggest the existence of two additional ${\mathrm{\Lambda }}_c$ baryons and two additional ${\mathrm{\Xi }}_c$ baryons. Their masses, mass splittings within the same multiplets, and decay properties are summarized in for future experimental searches.

We systematically explore the S-wave $D_1{D}_1$, $D_1{D}_2^{*}$ and $D_2^{*}{D}_2^{*}$ states with various isospin-spin-orbit ($ISL$) configurations in the quark model. We propose nine stable dimeson states with the $ISL$ configurations, $ISL=001$, 010, 012, 100, 102, 110, 112, 120, and 122, against dissociation into their constituent mesons. Those bound states are hydrogenlike molecular states, where the two subclusters are moderately overlapped and the QCD covalent bond is formed due to the delocalization of light quarks. The QCD covalent bond serves as the primary binding mechanism in the bound states with $I=1$. However, the exchange of $\pi$ and $\sigma$ mesons plays a pivotal role in the bound states with $I=0$. The coupled-channel effect is essential in the formation of the bound states with $ISL=001$, 010, 012, 100, and 102.

The modifications of $\varphi$ meson properties (masses and decay widths) are investigated in nuclear matter from the $\varphi$ meson self-energy, using the tree-level $\varphi K\overline{K}$ Lagrangian and incorporating in-medium masses of (anti)kaons calculated within the quark meson coupling (QMC) model. These mass shifts and decay widths are incorporated in the Breit-Wigner spectral function of the $\varphi$ meson to calculate the production cross section of $\varphi$ in asymmetric nuclear matter. Considerable modifications to the production cross section are observed at normal nuclear matter density, driven by the in-medium mass reduction and the increase in the decay width of $\varphi$ meson. The potential experienced by the $\varphi$ meson in nuclear matter is used to study the possibility of formation of the $\varphi$-mesic bound state with atomic nuclei. We explore the probable formation of $\varphi$-mesic bound states in ${}^4\mathrm{He}$, ${}^{12}\mathrm{C}$, ${}^{16}\mathrm{O}$, ${}^{40}\mathrm{Ca}$, ${}^{90}\mathrm{Zr}$, ${}^{197}\mathrm{Au}$, and ${}^{208}\mathrm{Pb}$ nuclei by investigating their binding energies and absorption widths based on the corresponding $\varphi$-nucleus potentials. Our study shows shallow bound states with the light nuclei and deeply bound states in heavy nuclei. Among the investigated nuclei, a particularly distinct signal for a $\varphi$-mesic bound state is identified in ${}^{16}\mathrm{O}$, suggesting its potential experimental observability. The work provides valuable insights into $\varphi$ meson interactions in infinite nuclear matter and the plausible formation of exotic $\varphi$-mesic nuclear states, offering promising probes for strongly interacting matter in the upcoming experiments at J-PARC, JLab, and $\overline{\mathrm{P}}\mathrm{ANDA}@\mathrm{FAIR}$ physics program.

We investigate potential hadronic molecular states in the $D^{(*)}{\overline{D}}^{(*)}$ and $B^{(*)}{\overline{B}}^{*}$ systems using light meson exchange interactions. Our analysis focuses on coupled-channel systems with spin-parity quantum numbers $J^{PC}=0^{++}$, $1^{+\pm }$, and $2^{++}$, examining how the $\delta (\mathit{r})$ potential affects states near threshold. Using coupled-channel analysis, we reproduce the $X(3872)$ mass with a given cutoff for the $(I)J^{PC}=(0)1^{++}$ state, finding a minimal impact from the $\delta (\mathit{r})$ term. At this cutoff, both the $(0)0^{++}$ state near the $D\overline{D}$ threshold and the $(0)1^{+-}$ state near the $D{\overline{D}}^{*}$ threshold show less sensitivity to the $\delta (\mathit{r})$ term compared to the three states–$(0)0^{++}$, $(0)1^{+-}$, and $(0)2^{++}$–near the $D^{*}{\overline{D}}^{*}$ threshold. As anticipated, the $B^{(*)}{\overline{B}}^{*}$ systems exhibit similar behavior but with stronger binding due to their larger reduced mass. These findings suggest promising directions for future experimental searches, particularly in the isoscalar sector, which could substantially advance our understanding of exotic tetraquark states.

We compute next-to-leading order QCD corrections to the $1/m_b^2$ terms of the heavy quark expansion, for the contribution to inclusive nonleptonic bottom hadron decays, induced by the charged-current operators mediating the $b\to c\overline{c}s$ transition. Their contributions to the lifetimes are Cabibbo favored and have large Wilson coefficients, but they have not been computed before, since the presence of two heavy quarks in the final state makes this calculation technically demanding. This work adds the last missing piece of the full NLO terms at $1/m_b^2$ in the heavy quark expansion of $B$-hadron lifetimes. We obtain analytical results with full dependence on the final-state charm quark mass.

In this study, we assess the effectiveness and robustness of the recently proposed $T^{\prime }$-expansion scheme for expanding the equation of state of strongly interacting matter to finite density, by comparing its performance relative to the conventional Taylor expansion method in various effective QCD models. We use baryon number density and its susceptibilities to calculate the expansion coefficients in the $T^{\prime }$-expansion scheme with and without the Stefan-Boltzmann limit correction. Our methodology involves comparing truncation orders to exact solutions to assess the scheme’s accuracy. We utilize ideal, excluded volume, and van der Waals formulations of the hadron resonance gas (HRG) model at low temperatures, and the cluster expansion model at higher temperatures. Our findings indicate that the $T^{\prime }$-expansion scheme offers superior convergence properties near and above the chiral crossover temperature, where the chiral-criticality-inspired scaling $(\partial /\partial T{)}_{{\mu }_B}\sim ({\partial }^2/\partial {\mu }_B^2{)}_T$ holds. However, it shows limited improvement in the HRG models, indicating that it may not be the most suitable choice for describing the hadronic phase.

We analyze the proton-box contribution to the hadronic light-by-light part of the muon’s anomalous magnetic moment, which is the first reported baryonic contribution to this piece. We follow the quark-loop analysis, incorporating the relevant data-driven and lattice proton form factors. Although the heavy mass expansion would yield a contribution of $\mathcal{O}({10}^{-10})$, the damping of the form factors in the regions where the kernel peaks explains our finding $a_{\mu }^{\mathrm{p}-\text{box}}=1.82(7)\times {10}^{-12}$, 2 orders of magnitude smaller than the forthcoming uncertainty on the $a_{\mu }$ measurement and on its Standard Model prediction.

A measurement of the Higgs boson mass and width via its decay to two $Z$ bosons is presented. Proton-proton collision data collected by the CMS experiment, corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$ at a center-of-mass energy of 13 TeV, is used. The invariant mass distribution of four leptons in the on-shell Higgs boson decay is used to measure its mass and constrain its width. This yields the most precise single measurement of the Higgs boson mass to date, $125.04\pm 0.12\mathrm{GeV}$, and an upper limit on the width ${\mathrm{\Gamma }}_H<330\mathrm{MeV}$ at 95% confidence level. A combination of the on- and off-shell Higgs boson production decaying to four leptons is used to determine the Higgs boson width, assuming that no new virtual particles affect the production, a premise that is tested by adding new heavy particles in the gluon fusion loop model. This result is combined with a previous CMS analysis of the off-shell Higgs boson production with decay to two leptons and two neutrinos, giving a measured Higgs boson width of ${3.0}_{-1.5}^{+2.0}\mathrm{MeV}$, in agreement with the standard model prediction of 4.1 MeV. The strength of the off-shell Higgs boson production is also reported. The scenario of no off-shell Higgs boson production is excluded at a confidence level corresponding to 3.8 standard deviations.

Key measurements at the future electron-ion collider (EIC), including first-of-their-kind studies of kaon structure, require the detection of ${\mathrm{\Lambda }}^0$ at forward angles. We present a feasibility study of ${\mathrm{\Lambda }}^0\to n{\pi }^0$ measurements using a high-granularity zero-degree calorimeter to be located about 35 m from the interaction point. We introduce a method to address the unprecedented challenge of identifying ${\mathrm{\Lambda }}^0\mathrm{s}$ with energy $O(100)\mathrm{GeV}$ that produce displaced vertices of $O(10)\mathrm{m}$. In addition, we present a reconstruction approach using graph neural networks. We find that the energy and angle resolution for ${\mathrm{\Lambda }}^0$ is similar to that for neutrons, both of which meet the requirements outlined in the EIC Yellow Report. Furthermore, we estimate performance for measuring the neutron’s direction in the ${\mathrm{\Lambda }}^0$ rest frame, which reflects the ${\mathrm{\Lambda }}^0$ spin polarization. We estimate that the neutral-decay channel ${\mathrm{\Lambda }}^0\to n{\pi }^0$ will greatly extend the measurable energy range for the charged-decay channel ${\mathrm{\Lambda }}^0\to p{\pi }^{-}$, which is limited by the location of small-angle trackers and the accelerator magnets. This work paves the way for EIC studies of kaon structure and spin phenomena.

Anti–de Sitter/QCD models are being extensively studied because they seem to offer an entirely tractable and radically different approach to the phases of QCD whose region of validity is precisely the region of strong interactions. In this context, a missing ingredient has been the absence of a bulk description dual to a confined hadronic phase at finite baryon density. In this work, we discuss a class of backgrounds that fill this lacuna. Applying physically motivated boundary conditions, we obtain phase diagrams which compare reasonably with approaches based on the Polyakov-Nambu-Jona-Lasino model. We also show that such backgrounds can play a similar role in geometries with a dilaton field.

We extract the complex frequency of the lowest quasinormal mode (QNM) from the holographically computed entropy density near thermodynamic equilibrium. The system under study is a purely thermal supersymmetric Yang-Mills $\mathcal{N}=4$ plasma undergoing homogeneous isotropization dynamics. Starting from a far-from-equilibrium initial state, the system evolves toward equilibrium entropy, forming a stairway pattern. Our analysis reveals that the rate of increase of the stairway is twice the decay rate (imaginary part) of the lowest QNM. Based on this observation, we propose a model that explains how this information is encoded in the entropy. The model is further extended to include finite temperature, R-charge density, and scalar condensate, revealing an additional feature: the system’s dominant dissipation channel may shift to one driven by the scalar condensate, depending on the chemical potential.

We study the patterns of multipartite entanglement in Chern-Simons theory with compact simple gauge group $G$ and level $k$ for states defined by the path integral on “link complements,” i.e., compact manifolds whose boundaries consist of $n$ topologically linked tori. We focus on link complements which can be described topologically as fibrations over a Seifert surface. We show that the entanglement structure of such fibered link complement states is controlled by a topological invariant, the monodromy of the fibration. Thus, the entanglement structure of a Chern-Simons link state is not simply a function of the link, but also of the background manifold in which the link is embedded. In particular, we show that any link possesses an embedding into some background that leads to Greenberger–Horne–Zeilinger state (GHZ)-like entanglement. Furthermore, we demonstrate that all fibered links with periodic monodromy have GHZ-like entanglement, i.e., a partial trace on any link component produces a separable state. These results generalize to any three dimensional topological field theory with a dual chiral rational conformal field theory.

In this work, we investigate the tidal deformability of regular black holes (RBHs). Employing different phenomenological models, we analyze their response to both test-field and gravitational perturbations, interpreting the latter within the framework of Einstein’s field equations in the presence of an appropriate exotic matter distribution. Numerical and analytical methods reveal that RBHs exhibit nontrivial tidal responses, influenced by their regularization parameters and exotic matter distributions. The results obtained for test-field and gravitational perturbations are in qualitative agreement. This hints at the possibility that similar conclusions could hold if these spacetimes were interpreted as solutions of a modified gravitational action. Our findings suggest that RBHs possess distinct, though subtle, tidal signatures, which may serve as observational probes of their internal structure in gravitational wave detections.

We present a new, monolithic first-order (both in time and space) BSSNOK formulation of the coupled Einstein-Euler equations. The entire system of hyperbolic Partial Differential Equations is solved in a completely unified manner via one single numerical scheme applied to both the conservative sector of the matter part and to the first-order strictly nonconservative sector of the spacetime evolution. The coupling between matter and spacetime is achieved via algebraic source terms. The numerical scheme used for the solution of the new monolithic first-order formulation is a path-conservative finite difference central Weighted Essentially Non-Oscillatory (WENO) scheme, with suitable insertions to account for the presence of the nonconservative terms. By solving several crucial tests of numerical general relativity, including a stable neutron star, Riemann problems in relativistic matter with shock waves, and the stable longtime evolution of single- and binary-puncture black holes up and beyond the binary merger, we show that our new central WENO scheme, introduced two decades ago for the compressible Euler equations of gas dynamics, can be successfully applied also to numerical general relativity, solving all equations at the same time with one single numerical method. In the future, the new monolithic approach proposed in this paper may become an attractive alternative to traditional methods that couple central finite difference schemes with Kreiss-Oliger dissipation for the spacetime part with totally different Total Variation Diminishing (TVD) schemes for the matter evolution and which are currently the state of the art in the field.