Self-interacting dark matter (SIDM) naturally gives rise to a cored isothermal density profile, which is favored in observations of many dwarf galaxies. The dark matter distribution in the presence of a central black hole in an isothermal halo develops a density spike with a power law of $r^{-7/4}$, which is shallower than $r^{-7/3}$ as expected for collisionless dark matter (CDM). Thus, indirect detection constraints on dark matter annihilations from the density spike could be relaxed in SIDM. Taking the most dense satellite galaxy of the Milky Way Draco as an example, we derive upper limits on the annihilation cross section and the black hole mass for both SIDM and CDM halos. For the former case, Draco could host an intermediate mass black hole even if dark matter is composed of thermal relics. We further explore the constraints from the Milky Way and M87, which host supermassive black holes, and show the upper limits on the annihilation cross section are significantly weakened in SIDM. Our results also indicate that the Event Horizon Telescope could provide a unique test of SIDM spikes.

We investigate nonrelativistic quantum-mechanical potentials between fermions generated by various classes of quantum field theory (QFT) operators and evaluate their singularity structure. These potentials can be generated either by four-fermion operators or by the exchange of a scalar or vector mediator coupled via renormalizable or nonrenormalizable operators. In the nonrelativistic regime, solving the Schrödinger equation with these potentials provides an accurate description of the scattering process. This procedure requires providing a set of boundary conditions. We first recapitulate the procedure for setting the boundary conditions by matching the first Born approximation in quantum mechanics to the tree-level QFT approximation. Using this procedure, we show that the potentials are nonsingular, despite the presence of terms proportional to $r^{-3}$ and ${\nabla }_i{\nabla }_j{\delta }^3(\overrightarrow{r})$. This surprising feature leads us to bifurcate the space of nonrelativistic quantum mechanical potentials into those which can be UV completed to a QFT and those which cannot. We identify preliminary criteria for distinguishing between these two classes of potentials. We also consider extensions to potentials in higher dimensions and find that Coulomb potentials are nonsingular in an arbitrary number of spacetime dimensions.

We introduce a numerical package FORward Experiment SEnsitivity Estimator, or $\mathtt{FORESEE}$, that can be used to simulate the expected sensitivity reach of experiments placed in the far-forward direction from the proton-proton interaction point. The simulations can be performed for 14 TeV collision energy characteristic for the LHC, as well as for larger energies; 27 and 100 TeV. In the package, a comprehensive list of validated forward spectra of various SM species is also provided. The capabilities of $\mathtt{FORESEE}$ are illustrated for the popular dark photon and dark Higgs boson models, as well as for the search for light up-philic scalars. For the dark photon portal, we also comment on the complementarity between such searches and dark matter direct detection bounds. Additionally, for the first time, we discuss the prospects for the LLP searches in the proposed future hadron colliders: High-Energy LHC (HE-LHC), Super proton-proton Collider (SppC), and Future Circular Collider (FCC-hh).

Recently, the BESIII Collaboration reported a resonance $Y(2040)$ with $M=2034\pm 13\pm 9\mathrm{MeV}$ and $\mathrm{\Gamma }=234\pm 30\pm 25\mathrm{MeV}$ in the process of $e^{+}{e}^{-}\to \omega {\pi }^0$. In addition, new measurements with much higher precision for the $\rho (1900)$ and $\rho (2150)$ states are obtained by the BESIII and BABAR Collaborations. In this work, we perform a systematic study on the mass spectrum of the excited $\rho$ resonances using the modified Godfrey-Isgur model, and the strong decays of $Y(2040)$, $\rho (1900)$, and $\rho (2150)$ within the ${}^3{P}_0$ model. We find that $Y(2040)$, $\rho (1900)$, and $\rho (2150)$ can be interpreted as the $\rho (2{{}^{3}D}_1)$, $\rho (3{{}^{3}S}_1)$, and $\rho (4{{}^{3}S}_1)$ states, respectively. Meanwhile, the mass and strong decays of the $\rho (3{{}^{3}D}_1)$ state are predicted as well, which could be helpful to search for this state in the future.

Baryon production is studied within the framework of quantized fragmentation of a QCD string. Baryons appear in the model in a fairly intuitive way, with the help of causally connected string breakups. A simple helical approximation of a QCD flux tube with parameters constrained by a mass spectrum of light mesons is sufficient to reproduce masses of light baryons.

The experiment Neutrino-4 started in 2014 with a detector model and continued with a full-scale detector in 2016–2021. In this article, we describe all the steps of the preparatory work on this experiment. We present all results of the Neutrino-4 experiment with increased statistical accuracy provided to date. The experimental setup is constructed to measure the flux and spectrum of the reactor antineutrinos as a function of distance to the center of the active zone of the SM-3 reactor (Dimitrovgrad, Russia) in the range of 6–12 meters. Using all the collected data, we performed a model-independent analysis to determine the oscillation parameters $\mathrm{\Delta }{\mathrm{m}}_{14}^2$ and ${\sin }^{2}2{\theta }_{14}$. The method of coherent summation of measurement results allows us to directly demonstrate the oscillation effect. We present the analysis of possible systematic errors and the MC model of the experiment, which considers the possibility of the effect manifestation at the present precision level. As a result of the analysis, we can conclude that at currently available statistical accuracy, we observe the oscillations at the $2.9\sigma$ level with the parameters $\mathrm{\Delta }{m}_{14}^2=(7.3\pm {0.13}_{\mathrm{st}}\pm {1.16}_{\mathrm{syst}}){\mathrm{eV}}^2=(7.3\pm 1.17){\mathrm{eV}}^2$ and ${\sin }^{2}2\theta =0.36\pm {0.12}_{\mathrm{stat}}(2.9\sigma )$. Monte Carlo based statistical analysis gave an estimation of the confidence level at $2.7\sigma$. We plan to improve the currently working experimental setup and create a completely new setup in order to increase the accuracy of the experiment by 3 times. We also provide a brief analysis of the general experimental situation in the search for sterile neutrinos.

We study the four-point function of the superconformal primary of the stress-tensor multiplet in four-dimensional $\mathcal{N}=4$ super Yang-Mills theory, at strong coupling and in a large-$N$ expansion. This observable is holographically dual to a four-graviton amplitude in type IIB supergravity on ${\mathrm{AdS}}_5\times S^5$. We construct the maximal transcendental weight piece of the correlator at order $N^{-6}$ and compare it with the flat-space limit of the corresponding two-loop amplitude. This allows us to conjecture structures of the correlator/amplitude which should be present at any loop order.

We report the results of the first search for the decay $B_s^0\to {\eta }^{\prime }\eta$ using $121.4{\mathrm{fb}}^{-1}$ of data collected at the $\mathrm{\Upsilon }(5S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We observe no significant signal and set a 90% confidence-level upper limit of $6.5\times {10}^{-5}$ on the branching fraction of this decay.

For the first time we systematically discuss the $N=1$ supersymmetric $SU(12{)}_C\times SU(2{)}_L\times SU(2{)}_R$ models, $SU(4{)}_C\times SU(6{)}_L\times SU(2{)}_R$ models, and $SU(4{)}_C\times SU(2{)}_L\times SU(6{)}_R$ models from the type IIA orientifolds on $T^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_2)$ with intersecting D6-branes. These gauge symmetries can be broken down to the Pati-Salam gauge symmetry $SU(4{)}_C\times SU(2{)}_L\times SU(2{)}_R$ via three $SU(12{)}_C/SU(6{)}_L/SU(6{)}_R$ adjoint representation Higgs fields, and further down to the Standard Model (SM) via the D-brane splitting and Higgs mechanism. We obtain three families of the SM fermions, and have the left-handed three-family SM fermion unification in the $SU(4{)}_C\times SU(6{)}_L\times SU(2{)}_R$ models, and the right-handed three-family SM fermion unification in the $SU(4{)}_C\times SU(2{)}_L\times SU(6{)}_R$ models. Utilizing mathematical analysis, we exclude the generalized $SU(12{)}_C\times SU(2{)}_L\times SU(2{)}_R$ models by requiring the conditions for constructing Minimal Supersymmetric Standard Model models. Moreover, the $SU(4{)}_C\times SU(6{)}_L\times SU(2{)}_R$ models and $SU(4{)}_C\times SU(2{)}_L\times SU(6{)}_R$ models are related by the left and right gauge symmetry exchanging, as well as a variation of type II T-duality. The hidden sector contains $USp(n)$ branes, which are parallel with the orientifold planes or their ${\mathbb{Z}}_2$ images and might break the supersymmetry via gaugino condensations.

The aim of this article is to explore the interplay between the eikonal resummation in impact-parameter space and the exponentiation of infrared divergences in momentum space for gravity amplitudes describing collisions of massive objects. The eikonal governs the classical dynamics relevant to the two-body problem, and its infrared properties are directly linked to the zero-frequency limit of the gravitational wave emission spectrum and to radiation-reaction effects. Combining eikonal and infrared exponentiations it is possible to derive these properties at a given loop order starting from lower-loop data. This is illustrated explicitly in $\mathcal{N}=8$ supergravity and in general relativity by deriving the divergent part of the two-loop eikonal from tree-level and one-loop elastic amplitudes.

Non-Abelian $U$ duality originates from the construction of exceptional Drinfel’d algebra (EDA), which extends the constriction of the classical Drinfel’d double. This symmetry is a natural extension of Poisson–Lie $T$ duality and is believed to be a symmetry of type II string/M-theory or their low-energy effective theories. In this paper, we consider non-Abelian $U$ dualities of 11- or 10-dimensional backgrounds starting with, $E_{n(n)}$ EDA with $n\le 6$ with vanishing trombone gauging. The latter guarantees that all dual backgrounds satisfy the standard supergravity equations of motion. In particular, when the duality includes a timelike $T$ duality, we obtain solutions of ${\mathrm{M}}^{*}$-theory or type ${\mathrm{II}}^{*}$ background equations, as expected. Also starting with coboundary EDA’s we provide examples of generalized Yang–Baxter deformations of M-theory and type IIB backgrounds. The obtained results provide explicit examples when non-Abelian $U$ duality works well as a solution generating transformation.

The scattering of Dirac fermions in the background fields of topological solitons of the ($2+1$)-dimensional nonlinear $O(3)$ $\sigma$-model is studied using both analytical and numerical methods. General formulas describing fermion scattering are obtained and the symmetry properties of the partial scattering amplitudes and elements of the $S$-matrix are determined. Within the framework of the Born approximation, the scattering amplitudes, differential cross sections, and total cross sections of fermion-soliton scattering are obtained in analytical forms, and their symmetry properties and asymptotic behavior are investigated. The dependences of the first several partial elements of the $S$-matrix on the momentum of the fermion are obtained using numerical methods, and some properties of these dependences are ascertained and discussed.

In theories with higher time derivatives, the Hamiltonian analysis of Ostrogradsky predicts an instability. However, this Hamiltonian treatment does not correspond the way that these theories are treated in quantum field theory, and the instability may be avoided in at least some cases. We present a very simple model which illustrates these features.

Recent works have explored nonperturbative effects due to the existence of (infinitesimal) Gribov copies in Yang-Mills-Chern-Simons theories in three Euclidean dimensions. In particular, the removal of such copies modify the gauge field propagator by a self-consistent dynamically generated mass parameter, the Gribov parameter. Due to the interplay with the topological mass introduced by the Chern-Simons term, the propagator features a nontrivial set of phases with poles of different nature, leading to the possible interpretation of a confinfing to deconfining phase transition. Here, we restore the Becchi–Rouet–Stora–Tyutin (BRST) symmetry which is softly broken by the elimination of gauge copies and provide a BRST-invariant discussion of such a transition. In order to make clear all physical statements, we deal with linear covariant gauges which contain a gauge parameter and therefore allow for an explicit check of gauge parameter independence of physical results. We also discuss the generation of condensates due to the infrared relevance of infinitesimal Gribov copies.

We revisit the definition of transverse frames and tetrad choices with regard to its application to numerically generated spacetimes, in particular those from the merger of binary black holes. We introduce the concept of local and approximate algebraic Petrov types in the strong-field regime. We define an index $\mathcal{D}=\sqrt{12/I}({\mathrm{\Psi }}_2-{\mathrm{\Psi }}_3^2/{\mathrm{\Psi }}_4)$ able to discriminate between Petrov types II and D and define regions of spacetime of those approximate types when used in conjunction with the speciality invariant $S=27J^2/I^3$. We provide an explicit example applying this method to Brill-Lindquist initial data corresponding to two nonspinning black holes from rest at a given initial separation. We find a doughnutlike region that is approximately of Petrov type II surrounded by an approximately Petrov type D region. We complete the study by proposing a totally symmetric tetrad fixing of the transverse frame that can be simply implemented in numerically generated spacetimes through the computation of spin coefficients ratios. We provide an application by explicitly deriving the Kerr-perturbative equations in this tetrad.

We prove the equivalence in the covariant phase space of the metric and connection formulations for Palatini gravity, with nonmetricity and torsion, on a spacetime manifold with boundary. To this end, we will rely on the cohomological approach provided by the relative bicomplex framework. Finally, we discuss some of the physical implications derived from this equivalence in the context of singularity identification through curvature invariants.

We construct several new classes of black hole (BH) solutions in the context of the mimetic Euler-Heisenberg theory. We separately derive three differently charged BH solutions and their relevant mimetic forms. We show that the asymptotic form of all BH solutions behaves like a flat spacetime. These BHs, either with or without cosmological constant, have a nonconstant Ricci scalar, due to the contribution of the Euler-Heisenberg parameter, which means that they are not a solution to standard or mimetic $f(R)$ gravitational theory without the Euler-Heisenberg nonlinear electrodynamics and at the same time they are not equivalent to the solutions of the Einstein gravity with a massless scalar field. Moreover, we display that the effect of the Euler-Heisenberg theory makes the singularity of BH solutions stronger compared with that of BH solutions in general relativity. Furthermore, we show that the null and strong energy conditions of those BH solutions are violated, which is a general trend of mimetic gravitational theory. The thermodynamics of the BH solutions are satisfactory although a negative Hawking temperature appears under some conditions. Additionally, these BHs obey the first law of thermodynamics. We also study the stability, using the geodesic deviation, and derive the stability condition analytically and graphically. Finally, for the first time and under some conditions, we derive multihorizon BH solutions in the context of the mimetic Euler-Heisenberg theory and study their related physics.

We investigate the presence of a black hole black string phase transition in Einstein-Gauss-Bonnet (EGB) gravity in the large dimension limit. The merger point is the static spacetime connecting the black string phase with the black hole phase. We consider several ranges of the Gauss-Bonnet parameter. We find that there is a range when the Gauss-Bonnet corrections are subordinate to the Einstein gravity terms in the large dimension limit, and yet the merger point geometry does not approach a black hole away from the neck. We cannot rule out a topology changing phase transition as argued by Kol. However as the merger point geometry does not approach the black hole geometry asymptotically it is not obvious that the transition is directly to a black hole phase. We also demonstrate that for another range of the Gauss-Bonnet parameter, the merger point geometry approaches the black hole geometry asymptotically when a certain parameter depending on the Gauss-Bonnet parameter $\alpha$ and on the parameters in the Einstein-Gauss-Bonnet black hole metric is small enough.

For a type of nonminimally coupled vector-tensor theories with Abelian gauge symmetry breaking in four-dimensional spacetime and correspondingly asymptotic non-AdS black hole solutions including a cosmological constant, we construct the appropriate boundary terms and derive the associated junction condition. In order to remove the divergences in the stress tensor which is localized on the spacetime boundary, we also involve the suitable surface counterterms into the total action. Using the counterterm method, we calculate the black hole mass. An implicit relation between the black hole carge $Q$ and other parameters is implied by combining the expression of the black hole mass with the first law of black hole thermodynamics. With this implicit relation, we can prove the inequality $Q\le M$ which is a general bound for most of charged black holes. Besides, the phase structure of black holes is also investigated in the grand canonical ensemble.