Given the absence of a definitive top-down indication for understanding the peculiar structure of the lepton sector, discrete flavor symmetries offer a profound perspective for examining the intricate patterns of lepton masses and mixings. In this work, drawing upon previous studies on the interplay of flavor symmetries with the potential UV completions from a purely bottom-up perspective, three well-motivated discrete flavor groups, suitable for portraying the leptonic sector as well as the neutrino masses, specifically $A_4$, $A_5$, and $S_4$, are explored within this framework, leading to the comprehensive classification of the new physics (NP) mediators, along with the tree-level matching relations onto dimension-6 Standard Model effective field theory operators. Particular emphasis is placed on the discrete leptonic directions, for which a phenomenological analysis is carried out in order to constrain various NP mediators, where significant focus is directed towards the examination of the charged lepton flavor violation operators, which, for the wide range of applicable cases, offer the leading constraint.

Recent analyses by CMS and ATLAS suggest a deviation in the diphoton channel at approximately 95 GeV, alongside a previously observed excess in $b\overline{b}$ signals at a similar mass by the Large Electron-Positron collider, potentially hinting at a new scalar particle. This study explores this possibility within the framework of the ${\mathbb{Z}}_3$-symmetric next-to-minimal supersymmetric standard model. A comprehensive parameter scan was conducted, integrating constraints from dark matter relic density, direct detection experiments, and the properties of the observed 125 GeV Higgs boson. The results demonstrate that the model can accommodate the observed excesses with a singlet-dominated $CP$-even scalar boson near 95 GeV. The model accurately predicts signal strengths of the diphoton and $b\overline{b}$ channels at a level of $1\sigma$. Furthermore, it accounts for the measured dark matter relic abundance through bino-dominated neutralinos coannihilation with winolike electroweakinos, all while remaining consistent with existing Large Hadron Collider (LHC) constraints. These findings pave the way for future validation at the high-luminosity LHC and linear colliders, which may offer crucial tests of the model’s predictions.

Exploring nuclear physics through the fundamental constituents of the strong force—quarks and gluons—is a formidable challenge. While numerical calculations using lattice quantum chromodynamics offer the most promising approach for this pursuit, practical implementation is arduous, especially due to the uncontrollable growth of quark-combinatorics, the so-called Wick-contraction problem of nuclei. We present here two novel methods providing a state-of-the art solution to this problem. In the first, we exploit randomized algorithms inspired from computational number theory to detect and eliminate redundancies that arise in Wick contraction computations. Our second method explores facilities for automation of tensor computations—in terms of efficient utilization of specialized hardware, algorithmic optimizations, as well as ease of programming and the potential for automatic code generation—that are offered by new programming models inspired by applications in machine learning (e.g., tensorflow). We demonstrate the efficacy of our methods by computing two-point correlation functions for Deuteron, Helium-3, Helium-4, and Lithium-7, achieving at least an order of magnitude improvement over existing algorithms with efficient implementation on GPU-accelerators. Additionally, we discover an intriguing characteristic shared by all the nuclei we study: specific spin-color combinations dominate the correlation functions, hinting at a potential connection to an as-yet-unidentified symmetry in nuclei. Moreover finding them beforehand can reduce the computing time further and substantially. Our results, with the efficiency that we achieved, suggest the possibility of extending the applicability of our methods for calculating properties of light nuclei, potentially up to $A\sim 12$ and beyond.

We develop a theoretical framework to match transverse momentum dependent parton distribution functions (TMD PDFs) onto chiral effective theory operators. In this framework the TMD PDF is expressed as a convolution of TMD hadronic distribution functions, which describe fluctuations of initial states into intermediate hadrons in chiral perturbation theory, and short distance matching coefficients, which are the TMD PDFs of intermediate hadrons in the chiral limit. The various limits of the matching condition are explored and an operator product expansion is applied to the high energy TMD matching coefficients, allowing them to be written in terms of the collinear valence PDFs of intermediate hadrons. As an example, we calculate the isovector TMD hadronic distribution functions for the proton at leading order in the chiral expansion.

The spin-singlet state ${\eta }_{c2}({}^1{D}_2)$ has not been discovered in experiment and it is the only missing low-excited $D$-wave charmonium, so in this paper, we like to study its properties. Using the Bethe-Salpeter equation method, we obtain its mass as 3828.2 MeV and its electromagnetic decay widths as $\mathrm{\Gamma }[{\eta }_{c2}(1D)\to h_c(1P)\gamma ]=284\mathrm{keV}$, $\mathrm{\Gamma }[{\eta }_{c2}(1D)\to J/\psi \gamma ]=1.04\mathrm{keV}$, $\mathrm{\Gamma }[{\eta }_{c2}(1D)\to \psi (2S)\gamma ]=3.08\mathrm{eV}$, and $\mathrm{\Gamma }[{\eta }_{c2}(1D)\to \psi (3770)\gamma ]=0.143\mathrm{keV}$. Considering the strong decay widths are estimated to be $\mathrm{\Gamma }({\eta }_{c2}(1D)\to {\eta }_c\pi \pi )=144\mathrm{keV}$ and $\mathrm{\Gamma }({\eta }_{c2}(1D)\to gg)=46.1\mathrm{keV}$, we obtain the total decay width of 475 keV for ${\eta }_{c2}(1D)$, and point out that the full width is very sensitive to the mass $M_{{\eta }_{c2}}$. In our calculation, the emphasis is put on the relativistic corrections. Our results show that ${\eta }_{c2}\to h_c\gamma$ is the nonrelativistic $E1$ transition dominated $E1+M2+E3$ decay, and ${\eta }_{c2}\to \psi \gamma$ is the $M1+E2+M3+E4$ decay but the relativistic $E2$ transition contributes the most.

A mechanism of generating $CP$ violation through the imaginary part of the interference of two amplitudes is proposed. This mechanism has shown clear evidence in decays such as $B^{\pm }\to {\pi }^{\pm }{\pi }^{+}{\pi }^{-}$. The proposed mechanism is helpful in searching for $CP$ violation in bottom and charmed baryon decay processes.

In this paper, we investigate different thermodynamic properties of $T\overline{T}+J\overline{T}$ deformed Schwarzian theory and its different gravitational perspectives. First, we compute the partition function of $U(1)$ coupled 2D-gravity with fixed chemical potential, obtained from the dimensional reduction of the four-dimensional Einstein-Maxwell theory. Then, we compute the partition function of the gravity theory which is the dual to the deformed Schwarzian living on its boundary and study the genus expansion of the one and two-point correlation function of the partition function of the theory. Subsequently, we use the one-point function to compute the “annealed” and “quenched” free energy in low-temperature limits and make a qualitative comparison with the undeformed theory. Then, using the two-point function, we compute the spectral form factor of the deformed theory in early and late time. We find a dip and ramp structure in early and late time, respectively. We also get a plateau structure in the $\tau$-scaling limit. Last but not least, we comment on the late-time topology change to give a physical interpretation of the ramp of the spectral form factor for our theory.

We report on an old computation of propagators of massless scalar fields on an ensemble of configurations in 4D Euclidean dynamical triangulations in the collapsed (crumpled) phase. The resulting quantum average is used to construct the scale factor of a 4D rotational invariant metric. This new scale factor is nonzero at the origin, which we assume to be caused the presence of the well-known singular structure in the collapsed phase. The scale factor depends on an overall integration constant, which is determined by comparison with the implied volume at intermediate distances. We construct a transformation to a 3D rotational invariant metric, which reveals Euclidean black hole features at an instant in time, with a horizon separating interior and exterior parts. Effective Einstein equations in the presence of a “geometric condensate” are assumed, and computed with the software ogre. Also explored briefly is a qualitatively different (not preferred) interpretation of the data which follows from comparison with an inversely transformed Euclidean regular black hole metric.

In analogy to null electromagnetic fields we define null Yang-Mills (YM) fields. We show that the null non-Abelian $SU(N)$ gauge fields admit a set of $2N^2$ conserved “helicities.” We derive null YM solutions that carry finite helicities by uplifting the Abelian Hopfion solution and their generalizations. Another method that we implement is to deform YM solutions which do not carry helicities into ones that have nontrivial helicities. A nontrivial non-Abelian solution with helicities is found as a wave of infinite energy. We also discuss non-Abelian generalizations of the Bateman parameterization for null Abelian gauge fields.

In this work, we study the geodesics in different Carrollian limits of RN (Reissner-Nordström) black holes, considering the motions of both neutral and charged particles. We use the geodesic equations in the weak Carrollian structure and analyze the corresponding trajectories projected onto the absolute space, and find that the geodesics are well defined. In particular, we examine the electric-electric and magnetic-electric limit of the RN black hole, focusing on their geodesic structures. We find that the global structures of the usual RN black holes get squeezed under the ultrarelativistic limit. More precisely, the nonextreme magnetic-electric RN spacetime has two different asymptotic flat patches while the extreme black hole spacetime consists of only one patch. For the magnetic-electric RN spacetime, the Carrollian extremal surfaces (CESs) divide the spacetime into several geodesically complete regions, and the geodesics can only travel in one of these regions. For the charged particles, we extend the analysis by considering their interactions with the electromagnetic field in the Carrollian RN spacetimes and find that their trajectories are significantly different from the neutral geodesics.

We present a new exact solution for a general non-BPS black ring in the bosonic sector of five-dimensional minimal supergravity. This obtained solution carries four independent conserved charges: the mass, two angular momenta, an electric charge, and an additional dipole charge related to other charges. By employing the Ehlers-Harrison transformation, we derive this solution by transforming a five-dimensional vacuum solution into a charged solution in the theory. Previously, our work produced a vacuum doubly rotating black ring solution possessing a Dirac-Misner string singularity by using the Ehlers transformation. In this study, we use the singular black ring as the seed for the Harrison transformation. The resultant solution is regular, free from curvature singularities, conical singularities, orbifold singularities, Dirac-Misner string singularities, and closed timelike curves both on and outside the horizon. We show that within a specific parameter range, the black ring presents two branches for the same mass, two angular momenta and electric charge but these are distinguished by a dipole charge, which exhibits discontinuous nonuniqueness. Furthermore, this newly obtained black ring seamlessly connects to various physically significant solutions, such as the Pomeransky-Sen’kov black ring, the extremal black ring, the supersymmetric black ring, and the charged singly spinning black ring.

We present a discussion of the periodicity in imaginary time of maximally extended black hole spacetimes without reference to Euclidean manifolds. As motivation, we first demonstrate our approach for the Rindler geometry in flat space before then applying it for the case of Schwarzschild time in the maximally extended Kruskal geometry. One notable advantage of our approach is that it can be utilized in the Kerr case, again without reference to a Euclidean manifold, and without complexifying the angular momentum parameter, $a$. One unusual feature of our application in the Kerr case is that, even for the purely Lorentzian geometry, it is developed in terms of explicitly complex coordinates which are associated with distinct families of $\alpha$-surfaces. Moreover, coordinatization of these gives a single set of coordinates which cover the entire geometry outside the inner horizon.

Astrophysical objects like black holes are usually surrounded by matter in the form of accretion disks or jets of matter. These astrophysical scenarios are expected to introduce novel phenomenology in the scattering of particles and fields. Wormholes are viable candidates for exotic compact objects that can mimic some black hole properties. Hence, it is natural to wonder what would happen if the central astrophysical object were a wormhole, instead of a black hole. We investigate the astrophysical environment effect on the absorption of a massless scalar field by a dirty wormhole surrounded by a thick shell of matter. We study null geodesics around these dirty wormholes and analyze under which conditions new pairs of light rings can appear. The presence of new stable light rings allows new quasibound states in the spacetime, apart from the ones trapped near the throat. Thus, the astrophysical environment can introduce deviations in the absorption bands. Remarkably, although heavy and dense distributions of matter are considered surrounding the wormhole, the position of most of the spectral lines in the absorption bands is preserved, indicating that the astrophysical environment cannot hide some fingerprints of the central object.

We present a surrogate model of SEOBNRv4PHM, a fully precessing time-domain effective-one-body waveform model including subdominant modes. We follow an approach similar to that used to build recent numerical relativity surrogate models. Our surrogate is 5000 M in duration, covers mass ratios up to $1:20$ and dimensionless spin magnitudes up to 0.8. Validating the surrogate against an independent test set, we find that the median mismatch error is less than ${10}^{-3}$, which is typically smaller than the modeling error of SEOBNRv4PHM itself. At high total mass, a few percent of configurations can exceed mismatches of ${10}^{-2}$ if they are highly precessing and exceed a mass ratio of $1:4$. This surrogate is nearly 2 orders of magnitude faster than the underlying time-domain SEOBNRv4PHM model and can be evaluated in $\sim 50\mathrm{ms}$. Bayesian inference analyses with SEOBNRv4PHM are typically very computationally demanding and can take from weeks to months to complete. The 2 order of magnitude speedup attained by our surrogate model enables practical parameter estimation analyses with this waveform family. This is crucial because Bayesian inference allows us to recover the masses and spins of binary black hole mergers given a model of the emitted gravitational waveform along with a description of the noise.

We investigate chaos in the dynamics of massless particles near the horizon of static spherically symmetric black holes in two well-motivated models of $f(R)$ gravity. In both these models, we probe chaos in the particle trajectories (under suitable harmonic confinement) in the vicinity of the black hole horizons, for a set of initial conditions. The particle trajectories, associated Poincaré sections, and Lyapunov exponents clearly illustrate the role played by the black hole horizon in the growth of chaos. We find that with increasing energy, the particle trajectories explore regions closer to the black hole horizon, with reduced overlap between two initially close trajectories. We demonstrate how this energy range is controlled by the parameters of the modified gravity theory under consideration. The growth of chaos in such a classical setting is known to respect a surface gravity bound arising from universal aspects of particle dynamics close to the black hole horizon [K. Hashimoto and N. Tanahashi, Phys. Rev. D 95, 024007 (2017)], analogous to the quantum Maldacena, Shenker, and Stanford bound [J. Maldacena et al., J. High Energy Phys. 08 (2016) 106]. Interestingly, both models studied in our work respect the bound, in contrast to some of the other models of $f(R)$ gravity in the existing literature. The work serves as a motivation to use chaos as an additional tool to probe Einstein gravity in the strong gravity regime in the vicinity of black hole horizons.

We study the spontaneous scalarization of Bardeen black holes, whose tachyonic instability triggers the formation of scalarized charged black holes (SCBHs). In this case, we find infinite ($n=0,1,2,\dots$) branches of SCBHs with magnetic charge $g$. The $n=0$ branch of SCBHs can be found for the coupling parameter $\alpha \ge {\alpha }_{n=0}(g)$ with both quadratic ($1-\alpha {\phi }^2$) and exponential ($e^{-\alpha {\phi }^2}$) couplings, where ${\alpha }_{n=0}(g)$ represents the threshold of tachyonic instability for the Bardeen black holes. Furthermore, it is shown that the $n=0$ branch for both couplings is stable against radial perturbations. This stability shows that this branch can be used for further observational implications.

A generic characteristic of self-gravitating systems is that they have a negative heat capacity. An important example of this behavior is given by the Schwarzschild black hole. The case of charged and rotating black holes is even more interesting since a change of sign of the specific heat takes place through an infinite discontinuity. This has been usually associated with a black hole thermodynamic phase transition appearing at the points where the heat capacity diverges, the so-called Davies points. This aspect of black hole thermodynamics has been addressed from different perspectives, motivating different interpretations since its discovery in the 1970s. In this paper, a physical reinterpretation of the heat capacity is provided for spherically symmetric and static black holes. Our analysis is partially based on a reformulation of the black hole heat capacity using the Newman-Penrose formalism. The application to the Reissner-Nordström-de Sitter black hole case reveals a clear physical interpretation of the Newman-Penrose scalars evaluated at the event horizon. This allows us to write the heat capacity as a balance of pressures defined at the horizon, in particular, a matter pressure (coming from the energy-momentum tensor) and a thermal pressure (coming from the holographic energy equipartition of the horizon). The Davies point is identified with the point where the Komar thermal energy density matches the matter pressure at the horizon. We also compare the black hole case with the case of self-gravitating objects and their corresponding thermal evolutions. We conclude that the heat capacity of black holes and self-gravitating systems can be understood qualitatively in similar terms.

The production of quantum field excitations or particles in cosmological spacetimes is a hallmark prediction of curved quantum field theory. The generation of cosmological perturbations from quantum fluctuations in the early Universe constitutes an important application. The problem can be quantum-simulated in terms of structure formation in an interacting Bose-Einstein condensate (BEC) with time-dependent s-wave scattering length. Here, we explore a mapping between cosmological particle production in general ($D+1$)-dimensional spacetimes and scattering problems described by the nonrelativistic stationary Schrödinger equation in one dimension. Through this mapping, intuitive explanations for emergent spatial structures in both the BEC and the cosmological system can be obtained for analogue cosmological scenarios that range from power-law expansions to periodic modulations. The investigated cosmologies and their scattering analogs are tuned to be implemented in a ($2+1$)-dimensional quantum field simulator.

The ratio of Bayesian evidences is a popular tool in cosmology to compare different models. There are however several issues with this method: Bayes’ factor depends on the prior even in the limit of noninformative priors, and the Jeffreys scale, used to assess the test, is arbitrary. Moreover, the standard use of Bayes’ factor is often criticized for being unable to reject models. In this paper, we address these shortcoming by promoting evidence ratios to frequentist statistics and deriving their sampling distributions. By comparing the evidence ratios to their sampling distributions, poor fitting models can now be rejected. Our method additionally does not depend on the prior in the limit of very weak priors, thereby safeguarding the experimenter against premature rejection of a theory with a uninformative prior, and replaces the arbitrary Jeffreys scale by probability thresholds for rejection. We provide analytical solutions for some simplified cases (Gaussian data, linear parameters, and nested models), and we apply the method to cosmological supernovae Ia data. We dub our method the FB method, for frequentist-Bayesian.

Self-interacting dark matter (SIDM) theory predicts that dark matter halos experience core collapse, a process where the halo’s inner region rapidly increases in density and decreases in size. The N-body simulations used to study this process can suffer from numerical errors when simulation parameters are selected incorrectly. Optimal choices for simulation parameters are well studied for cold dark matter, but are not deeply understood when self-interactions are included. In order to perform reliable N-body simulations and model core-collapse accurately we must understand the potential numerical errors, how to diagnose them, and what parameter selections must be made to reduce them. We use the arepo N-body code to perform convergence tests of core-collapsing SIDM halos across a range of halo concentrations and SIDM cross sections, and quantify potential numerical issues related to mass resolution, time step size, and gravitational softening length. Our tests discover that halos with fewer than ${10}^5$ simulation particles, a resolution typically not met by subhalos in N-body simulations, suffer from significant discreteness noise that leads to variation and extreme outliers in the collapse rate. At our lowest resolution of $N={10}^4$ particles, this collapse time variation can reach as high as 20%. At this low resolution we also find a bias in collapse times and a small number of extreme outliers. Additionally, we find that simulations which run far beyond the age of the Universe, which have been used to calibrate SIDM gravothermal fluid models in previous work, have a sensitivity to the time step size that is not present in shorter simulations or simulations using only cold dark matter. Our work shows that choices of simulation parameters that yield converged results for some halo masses and SIDM models do not necessarily yield convergence for others.