The spectrum of light unflavored vector mesons above 2.4 GeV has not yet been firmly established experimentally. In this work, we demonstrate that the process $e^{+}{e}^{-}\to p\overline{p}\pi$ serves as a particularly promising channel as a probe for higher isovector $\rho$ excitations. In contrast to typical electron-positron annihilation processes into purely light-meson final states, the reaction $e^{+}{e}^{-}\to p\overline{p}\pi$ benefits from a relatively low continuum background, on the order of $(50\sim 100)\mathrm{pb}$ around 2.4 GeV, which enhances the visibility of even modest resonance contributions. In addition, the comparatively high production threshold further suppresses potential contamination from lower $\rho$-meson excitations. Our analysis based on effective Lagrangian approach indicates that the observed line shape of the $e^{+}{e}^{-}\to p\overline{p}\pi$ cross section measured by the Beijing Spectrometer (BESIII) Experiment can be naturally interpreted by including the $\rho (5S)$ and $\rho (6S)$ contributions, namely the fourth and fifth radial excitations of $\rho (770)$. In particular, the pronounced rise of the cross section near 2.4 GeV provides strong evidence for the contribution of $\rho (5S)$ signal. Their branching ratios to the $p\overline{p}\pi$ final state are found to be below 4%, which do not contradict with usual expectations. In addition, we evaluate pion-induced production of these two $\rho$-meson states as a complementary probe, offering useful guidance for the relevant experiments such as the Common Muon and Proton Apparatus for Structure and Spectroscopy.

Using a data sample of $(2.712\pm 0.014)\times {10}^9\psi (3686)$ events collected with the BESIII detector at the BEPCII collider, we investigate the decays ${\chi }_{cJ}\to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}{\eta }^{\prime }$ for $J=0$, 1, 2 via the radiative transition $\psi (3686)\to \gamma {\chi }_{cJ}$. The decays ${\chi }_{c0,2}\to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}{\eta }^{\prime }$ are observed for the first time, with statistical significances of $6.7\sigma$ and $6.4\sigma$, respectively. Evidence for the decay ${\chi }_{c1}\to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}{\eta }^{\prime }$ is found with a statistical significance of $3.3\sigma$. The corresponding branching fractions are measured to be $ℬ({\chi }_{c0}\to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}{\eta }^{\prime })=(7.56\pm 1.42\pm 0.90)\times {10}^{-5}$, $ℬ({\chi }_{c1}\to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}{\eta }^{\prime })=(1.54\pm 0.51\pm 0.16)\times {10}^{-5}$, and $ℬ({\chi }_{c2}\to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}{\eta }^{\prime })=(3.03\pm 0.61\pm 0.29)\times {10}^{-5}$, where the first uncertainties are statistical and the second are systematic. No significant excited $\mathrm{\Lambda }$ baryon states or $\mathrm{\Lambda }\overline{\mathrm{\Lambda }}$ near-threshold enhancements are observed.

We formulate confinement in quantum chromodynamics (QCD) as an entropic surface phenomenon. Quark and gluon quantum information is localized on a transverse, entangling two-sphere of radius $R_{EE}$; at this radius the QCD vacuum—partitioned by a hadron into interior and exterior regions—reaches its maximal entanglement entropy. Lattice-QCD determinations of the scalar (trace) gravitational form factors fix both $R_{EE}$ and the transverse trace-anomaly density ${\rho }_h(R_{EE})$, yielding a parameter-free slope $c_h=8{\pi }^2{R}_{EE}^2{\rho }_h(R_{EE})$ and a mechanical entropy $S_{EE}(y)=c_{h}y$ that grows linearly with rapidity $y$. The entropy gradient ${\partial }_R{S}_{EE}$ changes sign at $R_{EE}$: it pushes colored degrees of freedom outward for $r<R_{EE}$ and pulls them inward for $r>R_{EE}$, thereby localizing them on the codimension-2 entangling two-sphere ${\mathrm{\Sigma }}_{\perp }=S_{R_{EE}}^2$ (which, in the infinite-momentum frame (IMF), projects onto the transverse plane)—the “information wall.” This provides a high-energy (large-$y$) entropic confinement diagnostic that complements—rather than replaces—Wilson’s area-law criterion, which probes long-distance dynamics near the rest frame ($y\to 0$). Imposing unitarity on an entropic ansatz for the amplitude yields $\sigma (s)\propto y^{\delta }$. World data favor $\delta =2$ for elastic $pp(p\overline{p})$ scattering and heavy-quark photoproduction, whereas $\varphi$ photoproduction favors a softer $\delta =0.387$. All extracted cross sections remain well below the Froissart-Martin bound. These results provide a confinement criterion quantified directly from nonperturbative QCD inputs, unifying the trace anomaly, entanglement entropy, and high-energy scattering within a single quantitative framework.

In this paper we employ lattice simulations to search for the critical point of QCD. We search for the onset of a first-order QCD transition on the phase diagram by following contours of constant entropy density from imaginary to real chemical potentials under conditions of strangeness neutrality. We scan the phase diagram and investigate whether these contours meet to determine the probability that the critical point is located in a certain region on the $T-{\mu }_B$ plane. To achieve this we introduce a new, continuum extrapolated equation of state at zero density with improved precision using lattices with $N_{\tau }=8$, 10, 12, 16 time slices, and supplement it with new data at imaginary chemical potential. The current precision allows us to exclude, at the $2\sigma$ level, the existence of a critical point at ${\mu }_B<450\mathrm{MeV}$.

We develop a new method for writing simple exact equations characterizing gravity solutions among which are black holes and in particular quasinormal modes. More precisely, we derive the full system of functional and thermodynamic Bethe ansatz nonlinear integral equations of quantum integrability. In particular, we prove that the quasinormal modes verify different equivalent exact quantization conditions and identify them with Bethe roots. We numerically solve the integral equation and compare the results with other methods. Eventually, we can definitely certify its simplicity, accuracy, and effectiveness. Furthermore, this method connects different unexpected fields and paves the way for innovative ways of investigations in gravity and gauge theories.

We study the stability of the Weyl geometry considering an exact black hole solution. By calculating the geodesics of massless and massive scalar fields orbiting outside the Weyl black hole background and using the Lyapunov exponent, we show that geodesic instabilities, characterized by the Lyapunov exponent, appear in the asymptotically de Sitter-like spacetime. Calculating the photon sphere’s quasinormal modes (QNMs) of a scalar field perturbing the Weyl black hole, we find a relation connecting the QNMs with the Lyapunov exponent in the asymptotically de Sitter-like spacetime. Furthermore, we study the anomalous decay rate of the QNMs connecting their behavior with the Lyapunov exponent.

We study the dynamics of electrically charged black-hole binaries and their gravitational-wave emission during the inspiral phase. Within the post-Newtonian framework, we derive the conservative and dissipative dynamics up to second order (2PN), combining Effective Field Theory and classical methods. We compute the next-to-next-to-leading-order conservative Lagrangian, leading-order dissipative effects in harmonic and Lorenz gauges, and provide the equations of motion, center-of-mass transformations, and the Lagrangian/Hamiltonian in Arnowitt-Deser-Misner-type coordinates. We also obtain gauge-invariant expressions for the binding energy, periastron advance in quasi-circular orbits, and the scattering angle in unbound orbits. Our results extend previous analyses and are fully consistent with recent post-Minkowskian findings.

Early James Webb Space Telescope (JWST) observations reveal an unexpectedly abundant population of high-redshift candidate massive galaxies at $z\gtrsim 7$, and recent Dark Energy Spectroscopic Instrument (DESI) measurements show a preference for dynamical dark energy, which together present a significant challenge to the standard $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) cosmology. In this work, we jointly analyze high-redshift galaxy data from JWST, baryon acoustic oscillations data from DESI Data Release 2 (DR2), and cosmic microwave background (CMB) data from Planck and Atacama Cosmology Telescope (ACT), measuring the total neutrino mass $\sum m_{\nu }$. We consider three dark energy models ($\mathrm{\Lambda }\mathrm{CDM}$, $w\mathrm{CDM}$, and $w_0{w}_a\mathrm{CDM}$) and three mass hierarchies. Our results indicate that in the $w_0{w}_a\mathrm{CDM}$ model, adding JWST data to $\mathrm{CMB}+\mathrm{DESI}$ tightens the upper limit of $\sum m_{\nu }$ by about 5.8%–10.2%, and we obtain $\sum m_{\nu }<0.167\mathrm{eV}$ ($2\sigma$) in the normal hierarchy (NH) case. Furthermore, JWST also offers indicative lower limits on star formation efficiency parameter of $f_{*,10}\gtrsim 0.146–0.161$. Bayesian evidence weakly favors the $w_0{w}_a\mathrm{CDM}+\sum m_{\nu }(\mathrm{NH})$ model relative to the $\mathrm{\Lambda }\mathrm{CDM}+\sum m_{\nu }(\mathrm{NH})$ model using $\mathrm{CMB}+\mathrm{DESI}+\mathrm{JWST}$ data. These results suggest that the joint analysis of high-redshift JWST data and low-redshift DESI data provides useful constraints on neutrino mass and merits further investigation.

Bulk viscosity, which characterizes the irreversible dissipative resistance of a fluid to volume changes, has been proposed as a potential mechanism for explaining both early- and late-time accelerated expansion of the Universe. In this work, we investigate two distinct physical scenarios for the origin of bulk viscosity: (1) nonminimal interactions between two fluids, and (2) elastic collisions in an ideal gas. In both cases, we demonstrate that while the associated energy-momentum exchange can significantly influence fluid dynamics, overall energy-momentum conservation precludes such exchange from having any direct gravitational effect in the context of General Relativity. In case (1), we show that the standard bulk viscous energy-momentum tensor can be obtained for the two-fluid system only at the cost of the violation of all classical energy conditions: null, weak, dominant, and strong. In case (2), we consider a single fluid composed of point particles undergoing instantaneous, energy- and momentum-conserving collisions, and find that the proper pressure remains strictly non-negative, with the equation-of-state parameter confined to the interval $[0,1/3]$. In both scenarios, achieving a sufficiently negative effective pressure to drive cosmic acceleration requires assumptions that compromise the physical viability of the model. Our results highlight some of the key physical challenges involved in modeling dark energy through bulk viscous effects.

We analyze radiative corrections to the predictions of Starobinsky-like models of inflation arising from self-interactions of the inflaton, and from its Yukawa couplings, $y$, to matter fermions, and dimensionful trilinear couplings, $\kappa$, to scalar fields, which could be responsible for reheating the Universe after inflation. The inflaton self-interactions are found to be of higher order in the Hubble expansion rate during inflation, and hence unimportant for CMB observations. In contrast, Einstein-frame matter couplings to an inflaton generating Starobinsky-like inflation can have significant effects on the spectral index of scalar CMB perturbations, $n_s$, and on the tensor-to-scalar ratio, $r$. Using a renormalization-group improved analysis of the effective inflationary potential, we find that the Planck measurement of $n_s$ constrains the inflaton coupling to light fermions in the Einstein frame; $y<4.5\times {10}^{-4}$, corresponding to an upper limit on the reheating temperature $T_{\mathrm{RH}}<2\times {10}^{11}\mathrm{GeV}$, whereas the ACT DR6 measurement of $n_s$ corresponds to $3.8\times {10}^{-4}<y<5.6\times {10}^{-4}$ and $1.7\times {10}^{11}\mathrm{GeV}<T_{\mathrm{RH}}<2.8\times {10}^{11}\mathrm{GeV}$, while the upper limits on $r$ provide weaker constraints. Planck data also imply a constraint on a trilinear inflaton coupling to light scalars in the Einstein frame: $\kappa \le 4\times {10}^{12}\mathrm{GeV}$, corresponding to $T_{\mathrm{RH}}\le 4.2\times {10}^{13}\mathrm{GeV}$. We further present constraints on inflaton couplings to massive fermions and scalars, and analyze constraints on couplings in the Jordan frame.

The fact that no Hawking radiation from the final stages of evaporating primordial black holes (PBHs) has yet been observed places stringent bounds on their allowed contribution to dark matter. Concretely, for Schwarzschild PBHs, i.e., uncharged and nonrotating black holes, this rules out black hole masses of less than ${10}^{-15}{M}_{\odot }$. In this article, we propose that by including an additional ‘dark’ $U(1)$ charge one can significantly lower the PBHs’ Hawking temperature, slowing down their evaporation process and significantly extending their lifetimes. With this, PBHs again become a viable option for dark matter candidates over a large mass range. We will explore in detail the effects of varying the dark electron (lightest dark charged fermion) mass and charge on the evaporation dynamics. For instance, we will show that by allowing the dark electron to have a sufficiently high mass and/or low charge, our approach suppresses both Hawking radiation and the Schwinger effect, effectively extending even the lifespan of PBHs with masses smaller than ${10}^{-15}{M}_{\odot }$ beyond the current age of the Universe. We will finally present a new lower bound on the allowed mass range for dark-charged PBHs as a function of the dark electron charge and mass, showing that the PBHs’ mass can get to at least as low as ${10}^{-24}{M}_{\odot }$ depending on the dark electron properties. This further demonstrates that the phenomenology of the evaporation of PBHs is ill-served by a focus solely on Schwarzschild black holes.

Numerical relativity simulations provide a means by which to study the evolution and end point of strong overdensities in cosmological spacetimes. Specific applications include studies of primordial black hole formation and the robustness of inflation. Here we adopt a toy model previously used in asymptotically flat spacetimes to show that, for given values of the overdensity and the mean curvature, solutions to the Hamiltonian constraint need not exist, and if they do exist they are not unique. Specifically, pairs of solutions exist on two branches, corresponding to strong-field and weak-field solutions, that join at a maximum beyond which solutions cease to exist. As a result, there is a limit to the extent to which an overdensity can be balanced by intrinsic rather than extrinsic curvature on the initial slice. Even below this limit, iterative methods to construct initial data may converge to solutions on either one of the two branches, depending on the starting guess, leading to potentially inconsistent physical results in the evolution.

In this work, we emphasize that it is necessary to take into account one-loop corrections of 2.0% to the neutrino matter potential in the precision measurements of neutrino oscillation parameters and in the experimental searches for new physics beyond the Standard Model. With the numerical simulation of the DUNE experiment, we study how radiative corrections to the matter potential affect neutrino oscillation probabilities, and thus, the event rates in the presence of neutrino nonstandard interactions (NSIs). We find that neglecting one-loop corrections may lead to wrong conclusions for the discovery of NSIs. The implications for the determination of neutrino mass ordering and constraints on the NSI parameters in future long-baseline accelerator neutrino experiments are explored in a quantitative way.

We define a relativistic version of the global symmetries responsible for the restricted mobility of fracton quasiparticles. The theories have a symmetry current that is proportional to a vector field that spontaneously breaks Lorentz boost symmetry. We argue that the existence of a pressureless dust in the early Universe could be a consequence of this symmetry. We provide an example of a fractonic scalar field with a quartic self-interaction evolving on a Friedmann-Robertson-Walker background and show that the interaction gives rise to a separately conserved fluid with equation of state $w=1$.

The $Z_2$ gauging of $Z_N$ symmetry can enforce the vanishing of certain elements of the fermion Yukawa couplings. We have performed a systematical study of texture-zero patterns of lepton mass matrices in the minimal seesaw model, and we have presented all the possible patterns of the charged-lepton Yukawa coupling $Y_E$, neutrino Yukawa coupling $Y_{\nu }$, right-handed neutrino mass matrix $M_R$, and the light neutrino mass matrix $M_{\nu }$, which can be derived from the $Z_2$ gauging of $Z_N$ symmetry. The realization of the textures with the maximum number of zeros and the second maximum number of zeros from noninvertible symmetry is studied, and the phenomenological implications in neutrino oscillation are discussed.

We investigate the $S$- and $P$-wave phase shifts for the $D{D}^{*}$ and $B{B}^{*}$ scatterings using Lüscher’s finite-size method under twisted boundary conditions to search for doubly charmed tetraquarks $T_{cc}^{+}$ and doubly bottomed tetraquarks $T_{bb}^{-}$ as the hadronic bound states. The $T_{cc}^{+}$ state was observed as a peak just below the $D{D}^{*}$ threshold by LHCb Collaboration, while the $T_{bb}^{-}$ state is a theoretically predicted tetraquark state having heavier quark flavors $bb\overline{u}\overline{d}$. Lüscher’s finite-size method is one of the well-established methods for calculating the scattering phase shifts between two hadrons in lattice QCD simulations. Several studies have used simulations under the periodic boundary condition to determine the scattering phase shifts at a few discrete momenta for the $D{D}^{*}$ system. However, the scattering phase shift has not been investigated for the $B{B}^{*}$ system. In this study, we investigate $S$- and $P$-wave scattering phase shifts for the $D{D}^{*}$ and $B{B}^{*}$ systems in both $I=0$ and $I=1$ channels under several types of partially twisted boundary conditions. The use of the partially twisted boundary conditions enables us to obtain the scattering phase shift at any momentum by continuously varying the twisting angle. It also allows us to easily access the $P$-wave scattering phase shifts through the mixing of $S$ and $P$ waves, which is induced by the imposed boundary conditions. The $2+1$ flavor PACS-CS gauge ensembles at $m_{\pi }=295$, 411, and 569 MeV are used. For charm and bottom quarks, the relativistic heavy quark action is adopted to reduce the lattice discretization artifacts due to the heavy quark mass. We discuss the emergence of a shallow bound state with a binding energy of $\mathcal{O}(100)\mathrm{keV}$ at the physical pion mass in the $B{B}^{*}$ system, which has the quantum number $I(J^P)=0(1^{+})$.

The Standard Model predicts a long-range force mediated by a pair of neutrinos, known as “the neutrino force.” It scales as $G_F^2/r^5$, where $G_F$ is the Fermi constant. However, as $r\lesssim \sqrt{G_F}$, the four-Fermi theory breaks down and the neutrino force no longer has the $1/r^5$ scaling. For the first time, we derive a complete expression for the neutrino force that is valid at all distances. For $r\gg \sqrt{G_F}$, the result reduces to the known $G_F^2/r^5$; for $r\ll \sqrt{G_F}$, it scales as $1/r$. We explore the implications of this result for atomic parity violation (APV) experiments. A key feature of the neutrino force is that it is a long-range effect compared to the atomic length scale. Thus, in general, it cannot be simply treated as a correction to the tree-level $Z$-exchange diagram without considering the atomic wave functions. We calculate the effects in muonium and positronium, finding that the neutrino force contributes about 4% and 16%, respectively, compared to the leading $Z$ exchange. This indicates a significant impact on APV, with important implications for detecting the neutrino force and measuring the weak mixing angle in APV experiments.

In this paper we calculate two-point correlation functions of a massive probe scalar field in the background of the three-dimensional Janus solution. We relate the equation of motion of the scalar to Heun’s equation and use the recently obtained expressions for the connection coefficients to obtain the two-point function of operators dual to the probe scalar. From the correlators we obtain the corrections to the spectrum of boundary operators and bulk-boundary operator product coefficients to second order in the Janus deformation parameter.

We propose a generalization of the Bogomol’ny–Prasad–Sommerfield Skyrme model [L. A. Ferreira, Exact self-duality in a modified Skyrme model, J. High Energy Phys. 07 (2017) 039] for simple compact Lie groups $G$ that leads to Hermitian symmetric spaces. In such a theory, the Skyrme field takes its values in $G$, while the remaining fields correspond to the entries of a symmetric, positive, and invertible $\dim G\times \dim G$-dimensional matrix $h$. We also use the holomorphic map Ansatz between $S^2\to G/H\otimes U(1)$ proposed in Ferreira and Livramento [Harmonic, holomorphic and rational maps from self-duality, arXiv:2412.02636] to study the self-dual sector of the theory, which generalizes the holomorphic Ansatz between $S^2\to C{P}^N$ proposed in Ioannidou [Low-energy states in the SU(N) Skyrme models, in International Meeting on Mathematical Methods in Modern Theoretical Physics (ISPM 98) (1998), pp. 91–123, arXiv:hep-th/9811071]. This Ansatz is constructed using the fact that stable harmonic maps of the two $S^2$ spheres for compact Hermitian symmetric spaces are holomorphic or antiholomorphic [J. Eells and L. Lemaire, Two Reports on Harmonic Maps (World Scientific Publishing Company, Singapore, 1995)]. Apart from some special cases, the self-duality equations do not fix the matrix $h$ entirely in terms of the Skyrme field, which is completely free, as it happens in the original self-dual Skyrme model for $G=SU(2)$. In general, the freedom of the $h$ fields tend to grow with the dimension of $G$. The holomorphic Ansatz enable us to construct an infinite number of exact self-dual Skyrmions for each integer value of the topological charge and for each value of $N\ge 1$, in case of the $C{P}^N$, and for each values of $p$, $q\ge 1$ in case of $SU(p+q)/SU(p)\otimes SU(q)\otimes U(1)$.