The coalescence production of the sexaquark, a hypothetical stable state with quark content $(uuddss)$, is investigated using the parton and hadron cascade model PACIAE in $pp$ collisions at $\sqrt{s}=7\mathrm{TeV}$. In this work, the compact sexaquark bound state of three diquarks is formed in the final partonic state by a two-step approach, which involves “diquark” formation via partonic coalescence and sexaquark construction with the dynamically constrained phase-space coalescence model successively. The yields, yield ratios, and dependences of the spatial parameters (the size of the diquark $D_0$ and the radius of the sexaquark $R_0$) of a (anti)sexaquark are predicted. The yields of the hadronic H-dibaryon molecule $\mathrm{H}(\mathrm{\Lambda }\mathrm{\Lambda })$ generated in the final hadronic state are also compared. These estimates provide references for future sexaquark searches and other exotic state studies, such as dibaryons.

We suggest a new look onto the thermodynamics of cold isospin quantum chromodynamics (QCD) matter described within the quarkyonic framework, when confining forces are essential only for the momentum states close to the Fermi sphere and lead to formation of the quark-antiquark correlations with quantum numbers of pions. Within this picture cold isospin QCD matter is constituted by the Bose-Einstein condensate of pions and free (anti)quarks. We develop a simple confining model of pions existing as the lowest energy $P$-state of in-medium three-dimensional harmonic oscillator and use it to show that under the conditions of isospin QCD quarkyonic matter can onset at densities significantly smaller than the overlap density of pions. Using the experimentally established pion charge radius we demonstrate that the onset density can be even lower than two nuclear saturation densities. To analyze the lattice QCD data we develop a field-theory inspired model of quark-antiquark-pion matter with vector-isovector repulsion among pions and (anti)quarks. The quark substructure of pions, which is one of the key elements of the model, is accounted for within the one-loop no-sea approximation and leads to an effective medium dependence of the pion mass. The latter is shown to be crucial for providing asymptotic vanishing of the pion density and pion condensate, which reflects pion dissociation due to asymptotic freedom of QCD. The proposed quarkyonic picture of isospin QCD agrees with the results of perturbative calculations on reaching the conformal limit of QCD and with the data of lattice simulations, which supports its viability and physical relevance.

The Any Light Particle Search II (ALPS II) experiment at Deutsches Elektronen-Synchrotron, Hamburg, is a light-shining-through-a-wall experiment aiming to probe the existence of axions and axionlike particles, which are candidates for dark matter. Data collection in ALPS II is underway utilizing a heterodyne-based detection scheme. A complementary run for confirmation or as an alternative method is planned using single photon detection, requiring a sensor capable of measuring low-energy photons (1064 nm, 1.165 eV) with high efficiency (higher than 50%) and a low background rate (below $7.7\times {10}^{-6}\mathrm{cps}$). To meet these requirements, we are investigating a tungsten Transition Edge Sensor (TES) provided by NIST, which operates in its superconducting transition region at millikelvin temperatures. This sensor exploits the drastic change in resistance caused by the absorption of a single photon. We find that the background observed in the setup with a fiber-coupled TES is consistent with Black Body Radiation (BBR) as the primary background contributor. A framework was developed to simulate BBR propagation to the TES under realistic conditions. The framework not only allows the exploration of background reduction strategies, such as improving the TES energy resolution, but also reproduces, within uncertainties, the spectral distribution of the observed background. These simulations have been validated with experimental data, in agreement with the modeled background distribution, and show that the improved energy resolution reduces the background rate in the 1064 nm signal region by 1 order of magnitude, to approximately ${10}^{-4}\mathrm{cps}$. However, this rate must be reduced further to meet the ALPS II requirements.

We consider black hole scattering up to the fifth post-Minkowskian ($G^5$) order and compare the predictions of the tutti frutti formalism to the results obtained within two different versions of worldline effective field theory. At the $G^4$ order we highlight the complete agreement between tutti frutti results and the results of [C. Dlapa et al., [Phys. Rev. Lett. 130, 101401 (2023)] ], and show how the tutti frutti approach allows one to extract the $O(G^3)$ angular momentum loss from the $O(G^4)$ impulse. We compare the sixth post-Newtonian (6PN) accurate tutti frutti predictions to the recent results of [M. Driesse et al., [Nature 641, 603 (2025)] ], which are at the $G^5$ order, and at the leading order in the two mass ratios, finding complete agreement. We highlight that this agreement involves the presence at the 5.5PN level of a nonlocal tail-of-tail contribution to the scattering (first computed in [D. Bini et al., [Phys. Rev. D 102, 084047 (2020)] ]), and involves, at the 6PN level, the presence of a $O(G^4)$ contribution to the angular momentum loss [C. Heissenberg, [Phys. Rev. D 111, 126012 (2025)] ]. At the second order in the mass ratios of the $O(G^5)$ order we predict two independent gauge-invariant observables to high-PN accuracy.

The third Gravitational-Wave Transient Catalog contains 90 binary coalescence candidates detected by the LIGO-Virgo-KAGRA Collaboration (LVK). We provide a reanalysis of binary black hole (BBH) events using a numerical relativity waveform surrogate model, NRSur7dq4, that includes all $\ell \le 4$ spin-weighted spherical harmonic modes as well as the complete physical effects of precession. Properties of the remnant black holes’ mass, spin vector, and kick vector are found using an associated remnant surrogate model NRSur7dq4Remnant. Both NRSur7dq4 and NRSur7dq4Remnant models have errors comparable to numerical relativity simulations and allow for high-accuracy parameter estimates. We restrict our analysis to 47 BBH events that fall within the regime of validity of NRSur7dq4 (mass ratios greater than $1/6$ and total masses greater than $60M_{\odot }$). While for most of these events, our results match the LVK analyses that were obtained using the semianalytical models such as IMRPhenomXPHM and SEOBNRv4PHM, we find that for more than 20% of events, the NRSur7dq4 model recovers noticeably different measurements of black hole properties like the masses and spins, as well as extrinsic properties like the binary inclination and distance. For instance, GW150914_095045 exhibits noticeable differences in spin precession and spin magnitude measurements. Other notable findings include one event (GW191109_010717) that constrains the effective spin ${\chi }_{\mathrm{eff}}$ to be negative at a 99.3% credible level and two events (GW191109_010717 and GW200129_065458) with well-constrained kick velocities. Furthermore, compared to the models used in the LVK analyses, NRSur7dq4 recovers a larger signal-to-noise ratio and/or Bayes factors for several events. While these findings have important astrophysical implications, some of the more interesting events are affected by transient detector noise, which can be challenging to remove from short-duration signals.

Recent observations from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2 (DR2) have revealed compelling evidence for dynamical dark energy, challenging the $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) paradigm. In this work, we adopt a data-driven, model-independent approach to reconstruct the dark energy equation of state (EOS) and its potential interaction with dark matter using combined background cosmological datasets, including DESI DR2, cosmic chronometers, observational Hubble data, and type Ia supernovae. Using Gaussian process regression and a nonparametric formalism, we first confirm an $\sim 2\sigma$ indication of dynamical dark energy, featuring a phantom crossing around redshift $z\sim 0.4$, which is consistent with the DESI results. We then explore the implications of dynamical EOS from DESI DR2 for dark sector coupling. Incorporating priors on the EOS from DESI DR2, we find an $\sim 2\sigma$ signal for nonzero interactions between dark energy and dark matter at low redshift. Our results suggest that if DESI’s evidence for time-varying dark energy is confirmed, a coupled dark sector may be a necessary extension beyond $\mathrm{\Lambda }\mathrm{CDM}$.

This study sets new constraints on $\mathrm{cold}+\mathrm{warm}$ dark matter (CWDM) models by leveraging the small-scale suppression of structure formation imprinted in the Lyman-$\alpha$ forest. Using the Sherwood-Relics suite, we extract high-fidelity flux power spectra from simulated Lyman-$\alpha$ forest data, spanning a broad range of cosmologies and thermal histories. This enables precise constraints on the warm dark matter (WDM) fraction, $f_{\mathrm{WDM}}$, and the mass of the WDM particle, $m_{\mathrm{WDM}}$. A key advancement of our analysis is the integration of a neural network emulator directly at the likelihood level, significantly accelerating Bayesian parameter inference. With new observations of high-redshift ($z=4.2–5.0$) quasar spectra from UVES and HIRES, we establish stringent upper limits: for $m_{\mathrm{WDM}}=1\mathrm{keV}$, we find $f_{\mathrm{WDM}}<0.16$ ($2\sigma$), with constraints loosening to 35%, 50%, and 67% for $m_{\mathrm{WDM}}=2,3$, and 4 keV, respectively. Our results for pure WDM reaffirm the lower bounds of previous work. Crucially, we account for the fixed resolution of simulations and the impact of patchy reionization, demonstrating their minimal influence on mixed dark matter constraints. This robustness paves the way for tighter bounds with improved statistical samples in the future. Our findings suggest that CWDM models can naturally accommodate mild suppression of matter clustering in the high-redshift Lyman-$\alpha$ forest 1D flux power, potentially offering a resolution to some of the ongoing cosmological tensions at low redshifts, namely the $S_8$ tension.

In this study, we use a flexible parametrization of the equation of state of dark energy to explore its possible evolution with datasets from the Dark Energy Spectroscopic Instrument (DESI), Planck cosmic microwave background (CMB), and either the 5-year Dark Energy Survey (DES) or the $\mathrm{Pantheon}+$ (PP) supernova (SN) compilation. This parametrization, called transitional dark energy (TDE), allows for rapid changes in the equation of state but also changes like that in the Chevallier-Polarski-Linder (CPL) $w_0–w_a$ parametrization. We find a $3.8\sigma$ preference for evolving dark energy over $\mathrm{\Lambda }\mathrm{CDM}$ with the DES SN dataset and a weaker $2.4\sigma$ preference when using the PP dataset. This corroborates the finding of the DESI Collaboration, who found that their baryon acoustic oscillation data preferred evolving dark energy when fit with the CPL parametrization of the equation of state. Our analysis reveals no significant outliers in the DESI data around the TDE best-fit, while the data is asymmetrically distributed around the $\mathrm{\Lambda }\mathrm{CDM}$ best-fit model such that the measured distances are on average smaller. The DESI and SN data both prefer an expansion history that implies a higher dark energy density around $z=0.5$ than in the Planck-$\mathrm{\Lambda }\mathrm{CDM}$ model, with the inferred equation of state being greater than $-1$ around $z=0$ and close to or below $-1$ at $z>0.5$. We show that when the expansion rate is greater than that in the Planck-$\mathrm{\Lambda }\mathrm{CDM}$ model (around $z=0.5$), the growth rate calculated assuming General Relativity is suppressed relative to the Planck-$\mathrm{\Lambda }\mathrm{CDM}$ model, and it rebounds as the expansion rate differences between the models become smaller closer to the present time. We derive an approximate analytic expression for the growth rate differences to understand this behavior quantitatively. The resulting flattening of the $f{\sigma }_8(z)$ curve compared to the $\mathrm{\Lambda }\mathrm{CDM}$ model could be an independent signature of the temporal evolution of dark energy.

The mathematical expression for the dark matter nuclear recoil event rate in a detector consists of a six-dimensional integral over the velocity distribution of dark matter in the detector frame and over the recoil momentum of the nucleus. While a significant part of this integral can be solved in closed form under traditional assumptions of the standard halo model and/or isotropic detector response, analysis of alternate assumptions is conventionally impeded by the inefficiency of multidimensional numerical integration methods. In this work, we introduce a novel, fast, and efficient algorithm for direct detection event rate computations. This algorithm takes advantage of a closed-form expression for the Radon transform of three-dimensional Zernike functions, which are used as basis functions for the velocity distribution. We demonstrate an implementation of this algorithm zebradm, which is typically faster than an optimized numerical integration approach by a factor between ${10}^2$ and ${10}^4$.

The diffuse neutrino and the stochastic gravitational wave (GW) backgrounds from binary neutron star mergers offer a wealth of physics information worth exploring. We study the feasibility of detection of both backgrounds as standalone and as multimessenger observations. Furthermore, we explore the possibility of setting additional constraints to the nuclear matter equation of state (EOS) based on these detections. We find that within the reach of the next generation of GW detectors, this stochastic GW background will show signatures of the EOS, in a frequency range of about 200–300 Hz (subjected to merger rates). As discussed elsewhere, while the detection of these relic neutrinos up to some cosmological distance is challenging, due to the presence of backgrounds from other sources, it is feasible by implementing searches following up the mergers’ GW observation. We find that analyzing the neutrino counts, in Hyper-Kamiokande enhanced with gadolinium (HK-Gd), during short time windows of a few milliseconds and in coincidence with GWs would provide significant background reduction. Additionally, based on this multimessenger strategy, we find that in a bit less than a decade of mergers’ observation, it would be possible to distinguish in HK-Gd between EOS types with a follow-up time window of about a second.

We perform axisymmetric general relativistic radiation-viscous hydrodynamics simulations of black hole (BH)-torus systems with full Boltzmann Monte Carlo neutrino transport to investigate the role of neutrino-antineutrino pair annihilation in launching relativistic outflows. Our models span a wide range of BH spins, torus masses, and viscosity parameters. We find that the pair annihilation leads to the formation of relativistic fireballs in most cases, except for those with low black-hole spin and high viscosity. The isotropic-equivalent energies of these outflows reach $\lesssim {10}^{51}\mathrm{erg}$ with durations $\lesssim 0.2\mathrm{s}$. While this is insufficient to explain the brightest short gamma-ray bursts (sGRBs), our results suggest that the pair annihilation may account for some low-luminosity sGRBs and GRB precursors. We also provide updated scaling relations for the pair annihilation energy deposition rate as a function of accretion rate, and discuss the sensitivity of outflow properties to numerical resolution and floor density.

We investigate the potential of light calorimetry in liquid argon time projection chambers and its intrinsic self compensation properties, emphasizing its advantages alongside conventional charge calorimetry. Previous studies have demonstrated that light calorimetry can achieve energy resolution comparable to advanced charge based techniques, particularly for GeV scale neutrinos. In this work, we explore the complementarity of light calorimetry with charge calorimetry for precision measurements of key physics parameters in the DUNE, including $CP$ violation ($CPV$) and mass hierarchy determination. While charge calorimetry provides superior resolution in $CP$ phase measurements, light calorimetry independently offers significant insights into $CPV$ and mass hierarchy sensitivities. Furthermore, our exposure versus $CPV$ sensitivity studies indicate that the $5\sigma$ discovery potential is reached faster using light and charge calorimetry than with the traditional Technical Design Report (TDR) based reconstruction method. These findings highlight the promising role of light calorimetry as a simple yet effective reconstruction method, serving as a complementary approach to enhance the physics capabilities of DUNE.

In the presence of a light singletlike scalar, the bino-dominated dark matter (DM) candidate in the ${\mathbb{Z}}_3$-symmetric next-to-minimal supersymmetric standard model (${\mathbb{Z}}_3$-NMSSM) exhibits notable deviations from its counterpart in the minimal supersymmetric standard model, both in terms of its inherent properties and the mechanisms determining its relic abundance and detection prospects. Motivated by recent progress in experimental particle physics, this study systematically investigates the implications for the ${\mathbb{Z}}_3$-NMSSM framework featuring a light bino-dominated DM particle and a light singletlike scalar, ensuring theoretical consistency with empirical observations. Of particular significance are the latest results from the LUX-ZEPLIN (LZ) direct detection experiment, supersymmetry searches at the Large Hadron Collider (LHC), and precision measurements of the Muon g-2 anomaly at Fermilab, which collectively impose complementary constraints on the model’s viable parameter space. A comprehensive parameter scan was conducted using the MultiNest algorithm, incorporating constraints from LZ-2022 data, LHC Higgs analyses, Muon g-2 measurements, and B-physics observables. The analysis reveals that current experimental limits—particularly those on spin-independent and spin-dependent DM-nucleon scattering cross sections and LHC constraints on electroweakinos—severely restrict the model. Nevertheless, the framework remains capable of naturally accommodating the observed $Z$ boson and standard-model-like Higgs boson masses, accounting for the Muon g-2 anomaly, and inducing sizable corrections to the $W$ boson mass. These results are distinctive to the NMSSM and emerge from the interplay of bino-dominated DM and singlino components, with essential contributions from higgsino.

We identify a new critical parameter in Choptuik’s gravitational collapse: the angle at which null energy condition (NEC) saturation lines intersect at the center of the critical spacetime. These NEC lines coincide with regions of vanishing curvature, dividing spacetime into stripes of positive and negative curvature. By numerically solving Choptuik’s original system, we find the NEC angle to be $\alpha \approx 0.64$ ($\approx 37°$) and analytically derive $\alpha =2\mathrm{arccot}(D-1)$ for any spacetime dimension $D>3$.

Recent investigations of Rényi entanglement entropy in the Sachdev-Ye-Kitaev (SYK) chain of Majorana fermions have indicated that the model exhibits slow thermalization when initialized in certain states. The extent to which the heavy modes—believed to underlie this behavior—affect other aspects of the model remains an open question. In this work, I study thermalization and scrambling of information in individual energy eigenstates of the SYK chain using exact diagonalization. I show that two-point correlation functions in finite-energy eigenstates closely match their thermal counterparts and that information scrambling occurs efficiently within these pure states. These results suggest that the slow thermalization observed in entanglement dynamics does not extend to all probes of thermalization and scrambling, even in pure states.

We study the Higgs branch moduli space of certain 6D (1, 0) superconformal field theories (SCFTs) after gauging their ${\mathbb{Z}}_2$ Green-Schwarz automorphism. We explain how to read the flavor symmetry of such SCFTs directly from the 6D construction, and we confirm the expectation by computing the Coulomb branch Hilbert series of their ${\mathbb{Z}}_2$-wreathed 3d $\mathcal{N}=4$ magnetic quiver. To perform the latter computation, we explicitly introduce a methodology to determine such Hilbert series for ${\mathbb{Z}}_2$-wreathed orthosymplectic quivers.

We analyze the double Wick rotated Bañados-Teitelboim-Zanelli (BTZ) black hole with the Euclidean signature, which is a Riemannian manifold. We calculate thermodynamics, total energy of spacetime, and holographic two-point functions in the double Wick rotated background. Results agree with those of a rotating BTZ with the same periodicity.

In this study, we generalize the work of Farhi, Guth, and Guven [Nucl. Phys. B339, 417 (1990)] by incorporating a wormhole and investigating the impact of the topological structure of spacetime on false vacuum bubble tunneling. In our model, the spherically symmetric bubble contains two domain walls. The classical dynamics of each domain wall are constrained by two classically forbidden regions. We find that the presence of a wormhole increases the number of instantons, thereby enhancing the tunneling rate. We analytically derive the tunneling rate formula, which reduces to the result obtained by Farhi, Guth, and Guven in the limit where the wormhole vanishes. Our results show that the tunneling rate increases with both the wormhole throat radius and the black hole mass. We demonstrate that the topological structure of spacetime influences domain wall tunneling. Within a limited range of parameters, we find that the tunneling rate increases with surface tension, while it decreases with the cosmological constant. In the case where a wormhole exists within a bubble and is connected to another universe, we demonstrate that the bubble can enter into another universe through quantum tunneling.

The late-time response of vacuum black holes in general relativity is notoriously governed by power-law tails arising from the wave scattering off the curved spacetime geometry far from the black hole. While it is known that such tails are universal to a certain extent, a precise characterization of their key ingredients is missing. Here we provide an analytical proof that the tail fall-off is universal for any effective potential asymptotically decaying as $1/r^2$, while the power-law decay is different if the potential decays as $1/r^{\alpha }$ with $1<\alpha <2$. This result extends and revises some previous work and is in agreement with numerical analyses. Our proof is based on an analytical evaluation of the branch cut contribution to the Green’s function, and includes charged black holes, different kinds of perturbations, the Teukolsky equation for the Kerr metric, exotic compact objects, extensions of general relativity, and environmental effects. In the latter case, our results indicate that tails are largely insensitive to a wide range of physically motivated matter distributions around black holes, including the Navarro-Frenk-White profile commonly used to model dark matter.