In this paper, we explore the natural grand unified theory (GUT) with spontaneous supersymmetry (SUSY) breaking, focusing on the contribution to sfermion and Higgs masses. Natural GUTs solve various problems in SUSY GUTs with the natural assumption that all terms allowed by $SO(10)\times U(1{)}_A$ symmetry are introduced with $O(1)$ coefficients. It is also possible to introduce spontaneous SUSY breaking in the natural GUT. This scenario predicts that $D$-term contribution to sfermion and Higgs masses dominates the $F$-term contribution, which potentially leads to the SUSY flavor problem. Fortunately, it also predicts high-scale SUSY, which avoids the SUSY flavor problem but leads to the instability of the electroweak scale. The $D$-term domination results in the superheavy Higgsino, unless the $D$-term contribution becomes comparable with the $F$-term contribution. We discuss whether it is possible to suppress the $D$-term contribution while maintaining the $F$-term contribution through the tuning of $O(1)$ coefficients in the natural GUT with spontaneous SUSY breaking. Our results indicate that it is impossible. This also suggests that the mass spectrum of the sfermions can be predicted by the $D$-term contributions and that the Higgsino is not a candidate for dark matter in the scenario.

A high baryon density and strong magnetic fields are expected in peripheral collisions in heavy-ion collision experiments, such as the upcoming Compressed Baryonic Matter experiment at facility for antiproton and ion research in Germany and nuclotron-based ion collider faсility in Russia. Such densities are also likely in the core of massive neutron stars, possibly with mixed quark-hadron phases. We employed the chiral effective model to obtain the constituent quark mass in this nonperturbative QCD regime. A quantized version of conductivity and resistivity is found reliable in the quantum domain of low density and high magnetic fields. Landau quantization gives rise to phenomena similar to SdH oscillations and quantum Hall effect in this regime. We have used a density-dependent magnetic field to observe SdH-type oscillations and the possibility of the quantum Hall effect in the interior of neutron stars where the magnetic field varies as a function of the baryon density. Our results indicate the possibility of observing the quantum Hall effect in a neutron star environment.

We present a comprehensive analysis of the angular structure of the Drell-Yan process at different rapidity and kinematical ranges using predictions of theoretical approaches (collinear perturbative QCD and the geometrical method) at next-to-leading order and data of ATLAS, LHCb, and CMS Collaborations at the CERN LHC.

$CP$ violation in the charmed baryon sector is generally expected to be very small, of order ${10}^{-4}$ or even smaller. Nevertheless, large long-distance penguin topologies can be induced through final-state rescattering. At the hadron level, they are manifested as the triangle and bubble diagrams. However, these diagrams consist of not only the penguin but also other tree topologies. Therefore, we focus on the flavor structure of the these diagrams and project out their contributions to penguin and tree topologies. The analysis is performed within the framework of the topological diagram approach and the irreducible SU(3) approach in which the SU(3) flavor symmetry of QCD is realized to describe the nonleptonic decays of charmed baryons. $CP$ violation at the per mille level is found in the following decay modes: ${\mathrm{\Lambda }}_c^{+}\to p{\pi }^0,{\mathrm{\Lambda }}_c^{+}\to p{\eta }^{\prime },{\mathrm{\Xi }}_c^0\to {\mathrm{\Sigma }}^0\eta$, and ${\mathrm{\Xi }}_c^{+}\to {\mathrm{\Sigma }}^{+}\eta$. $CP$ asymmetries in the last three modes receive sizable contributions from the SU(3)-flavor-singlet hairpin diagram.

Heavy flavor hadrons, especially doubly heavy baryons and doubly heavy tetraquarks, have always received extensive attention in theoretical and experimental research. Given the separation of quark masses $m_Q\gg m_q$ ($Q=c$, $b$ and $q=u$, $d$, $s$), this type of heavy flavor hadrons can be well regarded as hydrogenlike structures in the strong interaction. In the theoretical framework of Born-Oppenheimer approximation, we derive the Schrödinger equation for the motion of light quarks in the effective potential field of heavy quarks. Taking proper account of the color-spin hyperfine interaction, we carry out a systematic study on the mass spectra of $S$-wave doubly heavy baryons and doubly heavy tetraquarks. The model parameters required for the calculation are obtained by fitting conventional hadrons. The investigation on the doubly heavy baryon systems indicates the reliability of our theoretical approach. Our calculation results show that the experimentally discovered $T_{cc}^{+}$ is most likely a compact tetraquark $|(cc{)}_0^6(\overline{u}\overline{d}{)}_1^{\overline{6}}⟩$ state with quantum numbers $(I,J^P)=(0,1^{+})$. Furthermore, for different quantum number assignments, some stable tetraquark states are found and may be very narrow peaks. The predictions for other heavy flavor hadrons are expected to be confirmed in new theories and future experiments.

We calculate the next-to-leading order corrections to single inclusive hadron production in deep inelastic scattering at small $x$ using the color glass condensate formalism, for the case when the exchanged photon is transversely polarized. We show all UV and soft divergences cancel while collinear and rapidity divergences result in scale evolution of quark-hadron fragmentation function and small-x evolution of dipole amplitudes, respectively.

This study investigates the femtoscopic correlation functions of charmonium-nucleon pairs, utilizing the lattice QCD phase shifts provided by the HAL QCD Collaboration. A “model-independent” formalism is employed to transform scattering phase shifts directly into momentum correlation functions, thereby circumventing the approximations inherent in traditional methods, such as the Lednický-Lyuboshits model. The $J/\psi \text{−}p$ correlation functions, including spin-averaged and partial-wave results, are predicted using near-physical pion mass lattice results. The ${\eta }_c\text{−}p$ correlation function is calculated for the first time. The derived correlation functions provide critical references for future experiments, such as those at the LHC, where high-precision measurements of charmonium-nucleon correlations could unveil valuable insights into nonperturbative QCD dynamics.

We perform a comprehensive analysis of baryon number violation during an electroweak phase transition (EWPT) within the framework of a scalar electroweak multiplet extension of the Standard Model (SM). We classify the multiplet representations, topological properties, and corresponding thermal histories. Sphaleron or monopole topological field solutions emerge during the EWPT depending on the stage of the phase transition and the hypercharge of the new scalar multiplet. Furthermore, the monopole field solution pertains when the neutral component of the additional scalar multiplet is a viable dark matter candidate. We further analyze other formal considerations, including the construction of the “sphaleron matrix” for higher dimensional representations, computation of the sphaleron and monopole masses, and the choice of boundary conditions when solving the field equations of motion. We apply these considerations to the computation of sphaleron energy and monopole mass within the context of a multistep EWPT, employing the ${\mathrm{SU}(2)}_L$ septuplet scalar extension to the SM as a case of study from the minimal dark matter paradigm. For the first step of a two-step EWPT, we delineate the relationship between the monopole mass and the parameters relevant to dark matter phenomenology.

The first simultaneous measurements of the ${\nu }_{\mu }$ quasielasticlike cross section on C, CH, ${\mathrm{H}}_2\mathrm{O}$, Fe, and Pb targets as a function of kinematic imbalance variables in the plane transverse to the incoming neutrino direction are presented. These variables combine the muon and proton information to provide a new way to disentangle the effects of the nucleus in quasielasticlike processes. The data were obtained using a wideband ${\nu }_{\mu }$ beam with $⟨{\mathrm{E}}_{\nu }⟩\sim 6\mathrm{GeV}$. Cross-section ratios of the different target materials to CH are also shown. These measurements are used to explore the nature of the cross-section $A$ scaling, as well as initial and final state interaction effects. Comparisons are made to predictions from a number of commonly used neutrino Monte Carlo event generators. The range of predictions of the different models tends to cover the data but the degree and consistency of the agreement suffers in regions, and on higher $A$ targets, where the final state interactions are expected to be more pronounced.

We present a comprehensive study of the quasinormal modes of a new class of nonlocal static and spherically symmetric black hole (BH) solutions within the framework of the revised Deser-Woodard theory of gravity. These solutions are constructed as linear perturbations of the Schwarzschild spacetime and are characterized by an inverse power-law behavior of the lapse metric function. We derive the radial profiles of the effective potentials corresponding to scalar, electromagnetic, and axial gravitational fluctuations on the BH background. Using the WKB method, complemented by Padé approximants to regularize the trend of the effective potential near its peak, we compute the complex quasinormal mode frequencies associated with each type of perturbation. Our results are examined from both mathematical and physical perspectives, and are substantiated with references to existing literature. In particular, we compare the numerical outcomes with the predictions of the Schwarzschild metric to quantify deviations from the framework of general relativity. When all types of perturbations are combined, the relative deviations of the fundamental modes can reach up to $\sim 12\%$. Finally, we discuss the possibility to place observational bounds in the BH parameter space, based on the predicted sensitivities of future gravitational wave detectors.

We investigate whether a black hole (BH) surrounded by a dark matter halo has scalar hair/superradiant instability in the scalar tensor theory of gravity. In the scalar tensor theory, the coupling of matter and the scalar field creates effective mass, this effective mass causes the hairless BH to have scalar hair (spontaneous scalarization). In the case of rotating BHs, it is also known that if the sign of the effective mass is positive, superradiant instability can occur instead of scalarization. Our study applies this effect to BHs with dark matter haloes. As a result, we confirmed that scalarization and superradiant instability occur in some of the parameter regions. In the case of small haloes, the size and mass of the halo affect the strength of scalarization, but not for astronomically large haloes, where the dependence on the coupling constant $\alpha$ is stronger. In the case of superradiance, we also confirm that for small haloes, the size and mass of the halo affect the strength of the instability and the number of unstable modes.

The focus of this article is on a modification of general relativity (GR) governed by a dynamical scalar field. The latter is able to acquire a nonzero spacetime-dependent vacuum expectation value in a potential, which is a mechanism describing a spontaneous violation of spacetime symmetries. A broad class of spacetime-dependent potentials can be chosen allowing for a spacetime-dependent vacuum expectation value of the scalar field. The spacetime dependence of the potential can be parametrized by either another dynamical field or a nondynamical one. The second possibility introduces an aspect of explicit symmetry violation into the model, which is then interpreted as a hybrid. Based on the ($3+1$) decomposition, we demonstrate how to develop the Hamiltonian formulation for the hybrid theory. Having done so, our primary interest is to understand how spontaneous spacetime symmetry violation caused by the dynamical scalar via a mechanism manifests itself in such a setting. In particular, we find that the constraint structure of GR is preserved, although the constraints are clearly modified by the scalar field. This is the case even when the potential involves a nondynamical field, i.e., the latter is unessential for the constraint structure of the model. These results emphasize the beauty of spontaneous spacetime symmetry violation in gravity from the viewpoint of the Hamiltonian formulation. They may pose as the base for further studies of more sophisticated models of vector and higher-rank tensor fields. Moreover, the description developed can bear fruits when applied within phenomenological quests for spacetime symmetry violation in gravity, in particular, at cosmological scales.

We compute by means of post-Newtonian (PN) methods the innermost stable circular orbit (ISCO) of arbitrary-mass (in particular, comparable-mass) compact binaries. Two methods are used with equivalent results: dynamical perturbation of the conservative equations of motion in harmonic coordinates and dynamical perturbation of the conservative Hamiltonian in Arnowitt-Deser-Misner (ADM) coordinates. The perturbation of the nonlocal tail term at 4PN order in both approaches is carefully investigated. Our final gauge-invariant result for the location of the ISCO at 4PN order is close to the numerical value of the ISCO shift computed by the gravitational self-force approach in the small mass-ratio limit and is also in good agreement with the full numerical-relativity calculation in the case of equal masses. The PN method followed here is considered in standard Taylor-expanded form, without any resummation techniques applied. As a complement, we also compute explicitly the gauge transformation from harmonic coordinates to ADM coordinates up to 4PN order, including the tail contribution therein.

We study static, spherically symmetric neutron stars in a class of scalar-tensor theories with noncanonical kinetic terms (K-essence) obeying all causality and hyperbolicity conditions. These models have nontrivial dynamics that lead to a type of antiscreening of the scalar. They lead to small corrections in the solar system due to a small coupling, but can lead to large corrections in regimes of high densities, especially neutron stars. We solve the modified Tolman-Oppenheimer-Volkoff equations numerically using realistic equations of state (SLy4, WFF1, MS1, MPA1). For a given central density, we find that two distinct configurations may exist, forming two separate branches of solutions. We find that above a certain critical central density solutions with the correct asymptotic behavior at spatial infinity cannot be obtained. We obtain precise predictions for the mass-radius relation for neutron stars for different values of the parameters in the model and we compare to data.

Recent studies suggest that the most energetic cosmic rays, exceeding 100 EeV, may primarily consist of $r$-process nuclei. This highlights binary neutron star mergers and collapsars as promising sources of ultrahigh-energy cosmic rays (UHECRs). Building on these insights, we examine the conditions that facilitate the efficient production of UHE $r$-process nuclei during the prompt radiation (PR), extended emission (EE), and plateau emission phases of short gamma-ray bursts (sGRBs) following neutron star mergers. Our study reveals that jets associated with the PR phase, characterized by typical bulk Lorentz factors ($\gtrsim 400–500$), dissipation radii, and magnetic field strengths, can accelerate $r$-process nuclei to energies $\gtrsim 100\mathrm{EeV}$, while preserving them during propagation within the source. Additionally, we investigate the production of HE neutrinos from photomeson and hadronic interactions, as well as from the $\beta$ decay of accelerated $r$-process nuclei. We find that the HE neutrino fluxes from sGRBs, mainly produced via photomeson interactions, are significantly limited to preserve the accelerated heavy nuclei, leading to lower fluxes than the predictions without allowing for contributions to UHECRs. Our results suggest that sGRBs may potentially contribute to UHECRs during the PR phase and to HE neutrinos during the EE phase—a scenario that can be tested by future neutrino observatories.

A new tune (set of model parameters) is found for the six most important parameters of the pythia8 final state parton shower and hadronization model using Bayesian optimization. The tune fits the Large Electron-Positron collider (LEPI) data from ALEPH better than the default tune in pythia8. To the best of our knowledge, we present the most comprehensive application of Bayesian optimization to the tuning of a parton shower and hadronization model using the LEPI data.

We develop a theoretical framework for the production of $K^{+}{K}^{-}$ pairs through the decay of $\varphi$ mesons produced from a thermal background, based on the Nambu-Jona-Lasinio (NJL) model. The differential production rate of $K^{+}{K}^{-}$ is related to the self-energy of the $\varphi$ meson, incorporating the contributions of the quark loop at leading order and the kaon loop at next-to-leading order in the $1/N_c$ expansion. We numerically evaluate the invariant mass spectrum of the $K^{+}{K}^{-}$ pair both in vacuum and at finite temperature. The inclusion of the kaon loop results in a finite width of the spectrum, improving agreement with experimental data. We also investigate the spin alignment of the $\varphi$ meson induced by its motion relative to the thermal background. In the NJL model with only chiral condensates, we find that deviations from the unpolarized limit of $1/3$ are negligible.

Holographic models of QCD provide the spectrum of heavy vector meson masses and electromagnetic decay constants through bulk computations of the current-current correlation function. Conversely, the phenomenology of heavy vector mesons is articulated by the constituent heavy quark model utilizing a nonrelativistic approximation. By applying the Segre formula from nonrelativistic quantum mechanics, we derive new observables from holography: the constituent quark mass, the three-photon decay width, the effective fine structure constant of the strong interaction, and the mixed one-photon and two-gluon decay width. We also derive the three-gluon decay width, the three-photon decay width, and the mixed one-photon and two-gluon decay width for the radially excited states of heavy quarkonia and compare them with available experimental data. The present results reveal a new paradigm of meson spectroscopy in anti-de-Sitter (AdS)/QCD.

Computing the vacuum expectation of a fermion number operator on a soliton background is often challenging. A recent proposal in [1] simplifies this task by considering the soliton in a bounded region and relating the $\eta$ invariant, and thus the fermion number, to a specific heat kernel coefficient and to contributions from the edge states. We test this method in a system of charged fermions living on an Abrikosov-Nielsen-Olesen vortex background. We show that the resulting $\eta$ invariant does not depend on boundary conditions (within a certain class), thereby supporting the validity of the method. Our analysis reveals a nontrivial feature for the fermionic spectrum in the vortex-induced Higgs phase. As a by-product, we also find that for a vortex living on a disk, the edge states carry a fractional charge.

In this paper, it is shown that $N$-naturalness scenarios have an intrinsic mechanism to suppress neutrino masses. As in other infrared neutrino mass models like extra-dimensional theories or many species theories, the large number of mixing partners is responsible for the neutrino mass suppression. It is shown how neutrino mass matrices arise in $N$-naturalness models, and the resulting neutrino mixing is analyzed. The first result is that a totally democratic coupling among the different sectors like in the original models is already ruled out by the fact that neutrinos are not massless. In the case where the sector couplings deviate from the intersector ones a tower of additional neutrino mass eigenstates appears whose difference between the squared masses, $\mathrm{\Delta }{m}_{ij}^2$, is determined fully by the theory. The resulting phenomenology of such a tower is investigated, and the unique signals in neutrino oscillation experiments, neutrino mass measurements, and neutrinoless double beta decay experiments are discussed. This opens the door for terrestrial tests of $N$-naturalness whose phenomenology was so far focused on cosmology.