We have analyzed the reaction ${\chi }_{c0}\to \overline{p}{K}^{+}\mathrm{\Lambda }$ reported by the BESIII Collaboration, taking into account the contributions from the intermediate $K(1830)$, $N(2300)$, and $\mathrm{\Lambda }(1520)$ resonances. Our results are in good agreement with the BESIII measurements, and it is found that the anomalous enhancement near the $\overline{p}\mathrm{\Lambda }$ threshold is mainly due to the contribution of the $K(1830)$ resonance. We also show that the interference of the high-mass $N^{*}$ and ${\mathrm{\Lambda }}^{*}$ can not produce the anomalous enhancement near the $\overline{p}\mathrm{\Lambda }$ threshold.

We determine the $1/N_f^2$ and $1/N_f^3$ contributions to the QED beta function stemming from the closed set of nested diagrams. At the order of $1/N_f^2$, we discover a new logarithmic branch cut closer to the origin when compared to the $1/N_f$ results. The same singularity location appears at $1/N_f^3$, and these correspond to a UV renormalon singularity in the finite part of the photon two-point function.

We investigate simplified models involving an inert scalar triplet and vectorlike leptons that can account for the muon $g-2$ anomaly. These simplified scenarios are embedded in a model that features W’ and Z’ bosons, which are subject to stringent collider bounds. The constraints coming from the muon $g-2$ anomaly are put into perspective with collider bounds, as well as bounds coming from lepton flavor violation searches. The region of parameter space that explains the $g-2$ anomaly is shown to be within reach of lepton flavor violation probes and future colliders such as HL-LHC and HE-LHC.

The center vortex structure of the $SU(3)$ gauge field vacuum is explored through the use of novel visualization techniques. The lattice is partitioned into 3D time slices, and vortices are identified by locating plaquettes with nontrivial center phases. Vortices are illustrated by rendering vortex lines that pierce these nontrivial plaquettes. Nontrivial plaquettes with one dimension in the suppressed time direction are rendered by identifying the visible spatial link. These visualizations highlight the frequent presence of singular points and reveal an important role for branching points in $SU(3)$ gauge theory in creating high topological charge density regimes. Visualizations of the topological charge density are presented, and an investigation into the correlation between vortex structures and topological charge density is conducted. The results provide new insight into the mechanisms by which center vortices generate nontrivial gauge field topology. This work demonstrates the utility of visualizations in conducting center vortex studies, presenting new avenues with which to investigate this perspective of the QCD vacuum.

We present a formalism and detailed analytical results for soft-gluon resummation for $2\to n$ processes in single-particle-inclusive (1PI) kinematics. This generalizes previous work on resummation for $2\to 2$ processes in 1PI kinematics. We also present soft anomalous dimensions at one and two loops for certain $2\to 3$ processes involving top quarks and Higgs or $Z$ bosons, and we provide some brief numerical results.

Perturbative matching relates the parton quasidistributions, defined by Euclidean correlators at finite hadron momenta, to the light-cone distributions which are accessible in experiments. Previous matching calculations have exclusively focused on twist-2 distributions. In this work, we address, for the first time, the one-loop matching for the twist-3 parton distribution function $g_T(x)$. The results have been obtained using three different infrared regulators, while dimensional regularization has been adopted to deal with the ultraviolet divergences. We present the renormalized expressions of the matching coefficient for $g_T(x)$ in the $\overline{\mathrm{MS}}$ and modified $\overline{\mathrm{MS}}$ schemes. We also discuss the role played by a zero-mode contribution. Our results have already been used for the extraction of $g_T(x)$ from lattice QCD calculations.

Motivated by the desire to understand the nucleon mass structure in terms of light-cone distributions, we introduce the twist-four parton distribution function $F(x)$ whose first moment is the gluon condensate in the nucleon. We present the equation of motion relations for $F(x)$ and discuss the possible existence of the delta function (“zero mode”) contribution at $x=0$. We also perform one-loop calculations for quark and gluon targets.

We report on a search for elementary particles with charges much smaller than the electron charge using a data sample of proton-proton collisions provided by the CERN Large Hadron Collider in 2018, corresponding to an integrated luminosity of $37.5{\mathrm{fb}}^{-1}$ at a center-of-mass energy of 13 TeV. A prototype scintillator-based detector is deployed to conduct the first search at a hadron collider sensitive to particles with charges $\le 0.1e$. The existence of new particles with masses between 20 and 4700 MeV is excluded at 95% confidence level for charges between $0.006e$ and $0.3e$, depending on their mass. New sensitivity is achieved for masses larger than 700 MeV.

This erratum reports two inconsistencies in the definitions of the gravitational-wave (GW) amplitude $h_0$ across the different sections of this paper, as well as an overestimation of the numerically-computed GW timescale ${\tau }_{\mathrm{GW}}$.

We extend a bottom-up holographic model, which has been used in studying the color superconductivity in QCD, to the imaginary chemical potential (${\mu }_I$) region, and the phase diagram is studied on the ${\mu }_I$-temperature ($T$) plane. The analysis is performed for the case of the probe approximation and for the background, where the backreaction from the flavor fermions is taken into account. For both cases, we could find the expected Roberge-Weiss (RW) transitions. In the case of the backreacted solution, a bound of the color number $N_c$ is found to produce the RW periodicity. It is given as $N_c\ge 1.2$. Furthermore, we could assure the validity of this extended model by comparing our result with that of the lattice QCD near ${\mu }_I=0$.

We study Fayet-Iliopoulos (FI) terms of six-dimensional supersymmetric Abelian gauge theory compactified on a $T^2/Z_2$ orbifold. Such orbifold compactifications can lead to localized FI-terms and instability of bulk zero modes. We study 1-loop correction to FI-terms in more general geometry than the previous works. We find induced FI-terms depend on the complex structure of the compact space. We also find the complex structure of the torus can be stabilized at a specific value corresponding to a self-consistent supersymmetric minimum of the potential by such 1-loop corrections, which is applicable to the modulus stabilization.

Using the renormalization group improvement technique, we study the effective potential of a model consisting of $N$ scalar fields ${\varphi }^i$ transforming in the fundamental representation of an $O(N)$ group coupled to an additional scalar field $\sigma$ via cubic interactions, defined in a six-dimensional spacetime. We find that the model presents a metastable vacuum, which can be long-lived, where the particles become massive. The existence of attractive and repulsive interactions plays a crucial role in such phenomena.

We study a fermion field coupled to a scalar via a Yukawa term. The scalar field is the ${\varphi }^4$ model with an impurity that preserves half of the Bogomol’nyi-Prasad-Sommerfield (BPS) property. We analyze the spectrum of the defects of the model and collisions between them both close to the BPS regime and not. As the fermion binds to these defects, it may be transferred from one to the other, which we quantify via overlaps, known as Bogoliubov coefficients. BPS collisions are less likely to transfer the fermion between defects and can be adiabatic for nonrelativistic velocities, especially for small coupling constants. Moreover, closer to the BPS limit only a small fraction of the fermion number is radiated away. In contrast, non-BPS collisions lead to more radiation in the fermion field and excitation of the fermion to higher bound states, and the result is more sensitive to the parameters.

The Unruh effect is the phenomenon that accelerated observers detect particles even when inertial observers experience the vacuum state. In particular, uniformly accelerated observers are predicted to measure thermal radiation that is proportional to the acceleration. Here we consider the Unruh effect for a detector that follows a quantum superposition of different accelerated trajectories in Minkowski spacetime. More precisely, we analyze the excitations of a pointlike multilevel particle detector coupled to a massless real scalar field and moving in the superposition of accelerated trajectories. We find that the state of the detector excitations is, in general, not a mere (convex) mixture of the thermal spectrum characteristics of the Unruh effect for each trajectory with well-defined acceleration separately. Rather, for certain trajectories and excitation levels, and upon the measurement of the trajectory state, the state of the detector excitations features in addition off-diagonal terms. The off-diagonal terms of these “superpositions of thermal states” are related to the distinguishability of the different possible states in which the field is left after its interaction with detector’s internal degrees of the freedom.

The direct detection of gravitational waves by the LIGO/Virgo Collaboration has opened a new window with which to measure cosmological parameters such as the Hubble constant $H_0$, and also probe general relativity on large scales. In this paper we present a new phenomenological approach, together with its inferential implementation, for measuring deviations from general relativity (GR) on cosmological scales concurrently with a determination of $H_0$. We consider gravitational waves (GWs) propagating in an expanding homogeneous and isotropic background, but with a modified friction term and dispersion relation relative to that of GR. We find that a single binary neutron star GW detection will poorly constrain the GW friction term. However, a joint analysis including the GW phase and GW-GRB detection delay could improve constraints on some GW dispersion relations provided the delay is measured with millisecond precision. We also show that, for massive gravity, by combining 100 binary neutron stars detections with observed electromagnetic counterparts and host galaxy identification, we will be able to constrain the Hubble constant, the GW damping term and the GW dispersion relation with 2%, 15% and 2% accuracy, respectively. We emphasize that these three parameters should be measured together in order to avoid biases. Finally we apply the method to GW170817, and demonstrate that for all of the GW dispersions relations we consider, including massive gravity, the GW must be emitted $\sim 1.74\mathrm{s}$ before the gamma-ray burst. Furthermore, at the GW merger peak frequency, we show that the fractional difference between the GW group velocity and $c$ is $\lesssim {10}^{-17}$.

It was shown in a recent paper [J. Math. Phys. (N.Y.) 60, 102502 (2019)] that slowly lowering an electric charge into a Schwarzschild-Tangherlini (ST) black hole endows the final state with electric multipole fields, which implies that the final-state geometry is not Reissner-Nordström-Tangherlini in nature. This conclusion departs from the four-dimensional case in which the no-hair theorem (NHT) requires the final state to be a Reissner-Nordström black hole. To better understand this discrepancy clearly requires a deeper understanding of the origin of the multipole hair in the higher-dimensional case. In this paper, we advance the conjecture that charged, static, and asymptotically flat higher-dimensional black holes can acquire electric multipole hair only after they form. This supposition derives from studying the asymptotic behavior of the field of a multipole charge onto which a massive and hyperspherical shell with an exterior ST geometry is collapsing. In the mathematical limit as the shell approaches its ST radius, we find that the multipole fields (except the monopole) vanish. This implies that the only information of an arbitrary (but finite) charge distribution inside the collapsing shell that is available to an asymptotic observer is the total electric charge. Our results yield considerable insight into how higher-dimensional black holes acquire electric multipole hair, and also imply that, in four dimensions, the fadeaway of multipole moments during gravitational collapse is not strictly because of the NHT.

We study thermodynamics of the four-dimensional Kerr-Sen-AdS black hole and its ultraspinning counterpart and verify that both black holes fulfil the first law and Bekenstein-Smarr mass formulas of black hole thermodynamics. Furthermore, we derive new Christodoulou-Ruffini-like squared-mass formulas for the usual and ultraspinning Kerr-Sen-${\mathrm{AdS}}_4$ solutions. We show that this ultraspinning Kerr-Sen-${\mathrm{AdS}}_4$ black hole does not always violate the reverse isoperimetric inequality (RII) since the value of the isoperimetric ratio can be larger/smaller than, or equal to unity, depending upon where the solution parameters lie in the parameters space. This property is obviously different from that of the Kerr-Newman-${\mathrm{AdS}}_4$ superentropic black hole, which always strictly violates the RII, although both of them have some similar properties in other aspects, such as horizon geometry and conformal boundary. In addition, it is found that while there exists the same lower bound on mass ($m_e\ge 8l/\sqrt{27}$ with $l$ being the cosmological scale) both for the extremal ultraspinning Kerr-Sen-${\mathrm{AdS}}_4$ black hole and for the extremal superentropic Kerr-Newman-${\mathrm{AdS}}_4$ case, the former has a maximal horizon radius $r_{\mathrm{HP}}=l/\sqrt{3}$, which is the minimum of the latter. Therefore, these two different kinds of four-dimensional ultraspinning charged AdS black holes exhibit some significant physical differences.

The classical Hamiltonian for a chargeless and massless particle in a very near-horizon region is shown to be of the form $H\sim xp$ as long as radial motion is concerned. This is demonstrated explicitly for static spherically symmetric black hole and also found to be applicable for specific choice of radial trajectories in the Kerr case. Such feature of horizon leads to unavoidable “local instability” in the particle’s radial motion as long as near-horizon regime is concerned. We show that at the quantum level this provides thermality in the system. The temperature is found to be given by the Hawking expression. Finally, we conjecture that the automatic instability created by the horizon is responsible for its own temperature and consequently can be a possible physical mechanism for horizon temperature.

Recently the global variation of the Planck mass in the general relativistic Einstein-Hilbert action was proposed as a self-tuning mechanism of the cosmological constant preventing vacuum energy from freely gravitating. We show that this global mechanism emerges for generic local scalar-tensor theories with additional coupling of the scalar field to the field strength of a three-form gauge field that turns the scalar field constant on the domain of the action. Evaluation of the resulting integral constraint equation over the observable Universe yields a self-consistent framework with general relativistic field equations and arbitrary radiatively stable residual cosmological constant. We argue that the expectation value for this residual is in good agreement with the magnitude of the observed cosmic acceleration.