Extreme mass ratio inspirals (EMRIs) are important sources for space-borne gravitational wave detectors, such as the laser interferometer space antenna and TianQin. Previous EMRI rate studies have focused on the “loss cone” scenario, where stellar-mass black holes (sBHs) are scattered into highly eccentric orbits near the central massive black hole (MBH) via multibody interaction. In this work, we calculate the rate of EMRIs of an alternative formation channel: EMRI formation assisted by the accretion flow around accreting massive black holes. In this scenario, sBHs and stars on inclined orbits are captured by the accretion disk, and then subsequently migrate towards the MBH, under the influence of density wave generation and head wind. By solving the Fokker-Planck equation incorporating both sBH-sBH–sBH-star scatterings and sBH–star-disk interactions, we find that an accretion disk usually boosts the EMRI formation rate per individual MBH by $\mathcal{O}({10}^1–{10}^3)$ compared with the canonical loss cone formation channel. Taking into account that the fraction of active Galactic nuclei (AGNs) is $\sim \mathcal{O}({10}^{-2}-{10}^{-1})$, where the MBHs are expected to be rapidly accreting, we expect EMRI formation assisted by AGN disks to be an important channel for all EMRIs observed by space-borne gravitational wave detectors. These two channels also predict distinct distributions of EMRI eccentricities and orbit inclinations with respect to the MBH spin equatorial plane, which can be tested by future gravitational wave observations.

We present the automation of one-loop computations in the standard-model effective field theory at dimension 6. Our general implementation, dubbed smeft@nlo, covers all types of operators: bosonic and two- and four-fermion ones. Included ultraviolet and rational counterterms presently allow for fully differential predictions, possibly matched to the parton shower, up to the one-loop level in the strong coupling or in four-quark operator coefficients. Exact flavor symmetries are imposed among light quark generations, and an initial focus is set on top-quark interactions in the fermionic sector. We illustrate the potential of this implementation with novel loop-induced and next-to-leading-order computations relevant for top-quark, electroweak, and Higgs-boson phenomenology at the LHC and future colliders.

We show that the ($3+1$)-dimensional gauged nonlinear sigma model minimally coupled to a $U(1)$ gauge field possesses analytic solutions representing gauged solitons at finite baryon density whose electromagnetic field is a force-free plasma. These gauged solitons manifest a crystalline structure and generate in a very natural way persistent currents able to support force-free plasma electromagnetic fields. The trajectories of charged test particles moving within these configurations can be characterized. Quite surprisingly, despite the nonintegrable nature of the theory, some of the perturbations of these gauged solitons allow one to identify a proper resurgent parameter. In particular, the perturbations of the solitons profile are related to the Lamé operator. On the other hand, the electromagnetic perturbations on the configurations satisfy a two-dimensional effective Schrödinger equation, where the soliton’s background interacts with the electromagnetic perturbations through an effective two-dimensional periodic potential. We studied numerically the band energy spectrum for different values of the free parameters of the theory and we found that band gaps are modulated by the potential strength. Finally we compare our crystal solutions with those of the ($1+1$)-dimensional Gross-Neveu model.

Dilepton production from hot, dense and magnetized quark matter is studied using the three-flavor Polyakov loop extended Nambu–Jona-Lasinio (PNJL) model in which the anomalous magnetic moment (AMM) of the quarks is also taken into consideration. This is done by first evaluating the thermomagnetic spectral function of the vector current correlator employing the real time formalism of finite temperature field theory and the Schwinger proper time formalism. The constituent quark mass which goes as an input in the expression of the dilepton production rate (DPR), has been calculated using the three-flavor PNJL model employing Pauli-Villiars (PV) regularization. The obtained constituent quark mass being strongly dependent on the temperature, density, magnetic field and AMM of the quarks, captures the effect of “strong” interactions specifically around the (pseudo) chiral and confinement-deconfinement phase transition regions. The analytic structure of the spectral function in the complex energy plane has been analyzed in detail and a nontrivial Landau cut is found in the physical kinematic domains resulting from the scattering of the Landau quantized quark/antiquark with the photon which is purely a finite magnetic field effect. Due to the emergence of the Landau cut along with the usual unitary cut, the DPR is found to be largely enhanced in the low invariant mass region. Owing to the magnetic field and AMM dependence of the thresholds of these cuts, we find that the kinematically forbidden gap between the unitary and Landau cuts vanishes at sufficiently high temperature, density and magnetic field leading to the generation of a continuous spectrum of dilepton emission over the whole invariant mass region. In order to see the effects of strangeness and confinement-deconfinement, the rates are compared with the three-flavor NJL and the two-flavor NJL and PNJL models. Finally, an infinite number of quark Landau levels is incorporated in the calculation so that no approximations are made on the strength of the background magnetic field like strong or weak as usually done in the literature.

We minimally extend the Standard Model field content by adding new vectorlike fermions at the TeV scale to allow gauge coupling unification at a realistic scale. We embed the model into an SU(5) grand unified theory that is asymptotically safe and features an interacting fixed point for the gauge coupling. There are no Landau poles of the U(1) gauge and Higgs couplings in this new setting. Gauge, Yukawa, and Higgs couplings are retraced from the fixed point and matched at the grand unification scale to those of the Standard Model rescaled up to the same energy. All couplings, their fixed point values, and critical exponents always remain in the perturbative regime.

$U(1)$ global symmetry to solve the strong $CP$ problem could be a remnant of multi-$U(1)$ symmetries from QCD and hidden strong dynamics. Both Peccei-Quinn $U(1)$ and dynamical $U(1)$ are described uniformly, based on which we classify various mixed two-$U(1)$ models to solve both strong $CP$ and quality problems. We propose a moose diagram method with different fermion assignments to directly read relations between $CP$ phases, which illustrate how the strong $CP$ problem is solved in terms of cancellation between $CP$ phases. In two-axion models, we find that the lightest axion is still the same as a QCD axion in the infrared region, while a one-axion model with $Z_2$ symmetry enhances the axion mass spectrum. Our discussions can be extended to multiaxion cases.

We calculate tree-level scattering amplitudes of massive spin-2 Kaluza-Klein (KK) particles in models of stabilized compact extradimensional theories. Naïvely introducing a mass for the radion in an extra-dimensional model without accounting for the dynamics responsible for stabilizing the extra dimension upsets the cancellations relating the masses and couplings of the spin-2 modes, resulting in KK scattering amplitudes which grow like $E^4$ instead of $E^2$. We therefore investigate scattering of the Kaluza-Klein states in theories incorporating the Goldberger-Wise mechanism to stabilize the size of the extra dimension. We demonstrate that the cancellations occur only when one includes not only the massive radion, but also the massive spin-0 modes arising from the Goldberger-Wise scalar. We compute the revised sum rules which are satisfied in a stabilized model to ensure a consistent high-energy scattering amplitude. We introduce a simple model of a stabilized extra dimension which is a small deformation of a flat (toroidal) five-dimensional model, and demonstrate the cancellations in computations performed to leading nontrivial order in the deformation. These results are the first complete KK scattering computation in an extra-dimensional model with a stabilized extra dimension, with implications for the theory and phenomenology of these models.

Higgs production in association with a photon at hadron colliders is a rare process, not yet observed at the LHC. We show that this process is sensitive to significant deviations of Higgs couplings to first- and second-generation SM quarks (particularly the up type) from their SM values, and we use a multivariate neural network analysis to derive the prospects of the High Luminosity LHC to probe deviations in the up and charm Higgs Yukawa couplings through $h+\gamma$ production.

We extend previous work concerning rest-frame partial-wave mixing in Hamiltonian effective field theory to both elongated and moving systems, where two particles are in a periodic elongated cube or have nonzero total momentum, respectively. We also consider the combination of the two systems when directions of the elongation and the moving momentum are aligned. This extension should also be applicable in any Hamiltonian formalism. As a demonstration, we analyze lattice QCD results for the spectrum of an isospin-2 $\pi \pi$ scattering system and determine the $s$, $d$, and $g$ partial-wave scattering information. The inclusion of lattice simulation results from moving frames significantly improves the uncertainty in the scattering information.

Path integral contour deformations have been shown to mitigate sign and signal-to-noise problems associated with phase fluctuations in lattice field theories. We define a family of contour deformations applicable to $SU(N)$ lattice gauge theory that can reduce sign and signal-to-noise problems associated with complex actions and complex observables. For observables, these contours can be used to define deformed observables with identical expectation value but different variance. As a proof-of-principle, we apply machine learning techniques to optimize the deformed observables associated with Wilson loops in two dimensional $SU(2)$ and $SU(3)$ gauge theory. We study loops consisting of up to 64 plaquettes and achieve variance reduction of up to 4 orders of magnitude.

We present the first lattice-QCD determination of the form factors describing the semileptonic decays ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c^{*}(2595){\ell }^{-}\overline{\nu }$ and ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c^{*}(2625){\ell }^{-}\overline{\nu }$, where the ${\mathrm{\Lambda }}_c^{*}(2595)$ and ${\mathrm{\Lambda }}_c^{*}(2625)$ are the lightest charm baryons with $J^P={\frac{1}{2}}^{-}$ and $J^P={\frac{3}{2}}^{-}$, respectively. These decay modes provide new opportunities to test lepton flavor universality and also play an important role in global analyses of the strong interactions in $b\to c$ semileptonic decays. We determine the full set of vector, axial vector, and tensor form factors for both decays but only in a small kinematic region near the zero-recoil point. The lattice calculation uses three different ensembles of gauge-field configurations with $2+1$ flavors of domain-wall fermions, and we perform extrapolations of the form factors to the continuum limit and physical pion mass. We present Standard Model predictions for the differential decay rates and angular observables. In the kinematic region considered, the differential decay rate for the ${\frac{1}{2}}^{-}$ final state is found to be approximately 2.5 times larger than the rate for the ${\frac{3}{2}}^{-}$ final state. We also test the compatibility of our form-factor results with zero-recoil sum rules.

In this paper we consider the influence of relativistic rotation on the confinement-deconfinement transition in gluodynamics within lattice simulation. We perform the simulation in the reference frame which rotates with the system under investigation, where rotation is reduced to external gravitational field. To study the confinement-deconfinement transition, the Polyakov loop and its susceptibility are calculated for various lattice parameters and the values of angular velocities that are characteristic for heavy-ion collision experiments. Different types of boundary conditions (open, periodic, Dirichlet) are imposed in directions, orthogonal, to rotation axis. Our data for the critical temperature are well described by a simple quadratic function $T_c(\mathrm{\Omega })/T_c(0)=1+C_2{\mathrm{\Omega }}^2$ with $C_2>0$ for all boundary conditions and all lattice parameters used in the simulations. From this we conclude that the critical temperature of the confinement-deconfinement transition in gluodynamics increases with increasing angular velocity. This conclusion does not depend on the boundary conditions used in our study and we believe that this is universal property of gluodynamics.

The low-lying spectrum of the massless overlap Dirac operator coupled to Abelian fields in three dimensions with three different measures are shown to exhibit two phases: a strong coupling gapped phase and a weak coupling gapless phase. The vanishing of the gap from the strong coupling side with a Maxwell and a conformal measure is governed by a Gaussian exponent. Contrary to this result, the vanishing of the gap from the strong coupling side with a compact Thirring measure is not consistent with a Gaussian exponent. The low-lying spectrum with a noncompact Thirring measure does not exhibit a simple nonmonotonic behavior as a function of the lattice size on the weak coupling side. Our combined analysis suggests exploring the possibility of a strongly coupled continuum theory starting from a compact lattice Thirring model where a compact U(1) gauge field with a single link action is coupled to even number of flavors of massless overlap Dirac fermions.

I present a numerical study of the crossover between the low temperature chirally broken phase and the high temperature chirally restored phase in $SU(N_c)$ gauge theory with $N_c=3–5$ colors and $N_f=2$ degenerate fermion flavors. Fermion masses span a range of intermediate values corresponding to pseudoscalar to vector meson masses $(m_{PS}/m_V{)}^2\sim 0.25–0.63$. Observables include the temperature-dependent chiral condensate and screening masses. At each fermion mass these quantities show nearly identical temperature dependence across $N_c$.

A nonperturbative one-gluon exchange quark-antiquark interaction is considered to compute flavor-dependent U(3) Nambu–Jona-Lasinio-type (NJL-type) interactions of the form $G_{ij,\mathrm{\Gamma }}(\overline{\psi }{\lambda }_i\mathrm{\Gamma }\psi )(\overline{\psi }{\lambda }_j\mathrm{\Gamma }\psi )$ for $i,j=0\dots 8$ and $\mathrm{\Gamma }=I,i{\gamma }_5$ from the one-loop polarization process with nondegenerate u-d-s quark effective masses. The resulting NJL-type coupling constants in all channels are resolved in the long-wavelength limit and the numerical results are presented for different choices of an effective gluon propagator. Leading deviations with respect to a flavor symmetric coupling constant are found to be of the order $(M_{f_2}^{*}-M_{f_1}^{*}{)}^n/(M_{f_2}^{*}+M_{f_1}^{*}{)}^n$, for $n=1$, 2, where $M_{f_i}^{*}$ are the effective masses of quarks $f_1,f_2=u$, $d$ and $s$. The scalar channel coupling constants $G_{ij,s}$ can be considerably smaller than the pseudoscalar ones. The effect of the flavor-dependence of coupling constants for the masses of pions and kaons may be nearly of the same order of magnitude as the effect of the u, d, and s quark mass nondegeneracy. The effect of these coupling constants is also verified for some of the light scalar meson masses, usually described by quark-antiquark states, and for some observables of the pseudoscalar mesons.

We propose a new method for unsupervised clustering for collider physics named UCluster, where information in the embedding space created by a neural network is used to categorize collision events into different clusters that share similar properties. We show how this method can be developed into an unsupervised multiclass classification of different processes and applied in the anomaly detection of events to search for new physics phenomena at colliders.

Using $6.32{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected by the BESIII detector at the center-of-mass energies between 4.178 and 4.226 GeV, an amplitude analysis of the $D_s^{+}\to K_S^0{K}^{-}{\pi }^{+}{\pi }^{+}$ decays is performed for the first time to determine the intermediate-resonant contributions. The dominant component is the $D_s^{+}\to K^{*}(892{)}^{+}{\overline{K}}^{*}(892{)}^0$ decay with a fraction of $(40.6\pm 2.9_{\mathrm{stat}}\pm 4.9_{\mathrm{sys}})\%$. Our results of the amplitude analysis are used to obtain a more precise measurement of the branching fraction of the $D_s^{+}\to K_S^0{K}^{-}{\pi }^{+}{\pi }^{+}$ decay, which is determined to be $(1.46\pm 0.05_{\mathrm{stat}}\pm 0.05_{\mathrm{sys}})\%$.

We study causal diamonds in Minkowski, Schwarzschild, (anti–)de Sitter, and Schwarzschild–de Sitter spacetimes using Euclidean methods. The null boundaries of causal diamonds are shown to map to isolated punctures in the Euclidean continuation of the parent manifold. Boundary terms around these punctures decrease the Euclidean action by $A_{\diamond }/4$, where $A_{\diamond }$ is the area of the holographic screen around the diamond. We identify these boundary contributions with the maximal entropy of gravitational degrees of freedom associated with the diamond.

In this paper, we will analyze the effects of superlight braneworld perturbative modes on clustering of galaxies. In the present manuscript, we use the Boltzmann and Tsallis statistical approaches to study the large distance modification of gravity in the braneworld. The impact of modified potential on clustering of galaxies is analyzed in both the approaches. The infinities associated with Newtonian point mass approximation of gravity models is removed using the analytical extensions. The regularized and finite partition function is obtained for the system of galaxies in the braneworld model and is used to evaluate the regularized thermodynamic properties of the system in the form of equations of state. Hence, we study thermodynamic quantities and discuss about the thermodynamic stability of the model. We find that large number of galaxies may lead to the thermodynamic instability. The appealing feature of the paper revolve around the generalization of the dimensional regularization (GDR) of Bollini and Giambiagi supplemented with the statistical adequacy of Boltzmann and Tsallis.

The stability and other physical properties of a class of regular black holes, quasiblack holes, and other electrically charged compact objects are investigated in the present work. The compact objects are obtained by solving the Einstein-Maxwell system of equations assuming spherical symmetry in a static spacetime. The spacetime is split in two regions by a spherical surface of coordinate radius $a$. The interior region contains a nonisotropic charged fluid with a de Sitter type equation of state, $p_r=-{\rho }_m$, $p_r$ and ${\rho }_m$ being respectively the radial pressure and the energy density of the fluid. The charge distribution is chosen as a well behaved power-law function. The exterior region is the electrovacuum Reissner-Nordström metric, which is joined to the interior metric through a spherical thin shell (a thin matter layer) placed at the radius $a$. The matter of the shell is assumed to be a perfect fluid satisfying a linear barotropic equation of state, $\mathcal{P}=\omega \sigma$, with $\mathcal{P}$ and $\sigma$ being respectively the pressure and energy density of the shell, with $\omega$ being a constant. The exact solutions obtained are analyzed in some detail by exploring the interesting regions of parameter space, complementing the analysis of previous works on similar models. This is the first important contribution of the present study. The stability of the solutions are then investigated considering perturbations around the equilibrium position of the shell. This is the second and the most important contribution of this work. We find that there are stable objects in relatively large regions of the parameter space. In particular, there are stable regular black holes for all values of the parameter $\omega$ of interest. Other stable ultracompact objects as quasiblack holes, gravastars, and even overcharged stars are allowed in certain regions of the parameter space.