Differential cross section measurements of $W^{\pm }\gamma$ production in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ are presented. The data set used in this study was collected with the CMS detector at the CERN LHC in 2016–2018 with an integrated luminosity of $138{\mathrm{fb}}^{-1}$. Candidate events containing an electron or muon, a photon, and missing transverse momentum are selected. The measurements are compared with standard model predictions computed at next-to-leading and next-to-next-to-leading orders in perturbative quantum chromodynamics. Constraints on the presence of TeV-scale new physics affecting the $WW\gamma$ vertex are determined within an effective field theory framework, focusing on the ${\mathcal{O}}_{3W}$ operator. A simultaneous measurement of the photon transverse momentum and the azimuthal angle of the charged lepton in a special reference frame is performed. This two-dimensional approach provides up to a factor of ten more sensitivity to the interference between the standard model and the ${\mathcal{O}}_{3W}$ contribution than using the transverse momentum alone.

With the increasing sensitivity of gravitational-wave detectors, we expect to observe multiple binary neutron-star systems through gravitational waves in the near future. The combined analysis of these gravitational-wave signals offers the possibility to constrain the neutron-star radius and the equation of state of dense nuclear matter with unprecedented accuracy. However, it is crucial to ensure that uncertainties inherent in the gravitational-wave models will not lead to systematic biases when information from multiple detections is combined. To quantify waveform systematics, we perform an extensive simulation campaign of binary neutron-star sources and analyze them with a set of four different waveform models. For our analysis with 38 simulations, we find that statistical uncertainties in the neutron-star radius decrease to $\pm 250\mathrm{m}$ (2% at 90% credible interval) but that systematic differences between currently employed waveform models can be twice as large. Hence, it will be essential to ensure that systematic biases will not become dominant in inferences of the neutron-star equation of state when capitalizing on future developments.

Solutions to vacuum Einstein field equations with cosmological constants, such as the de Sitter space and the anti–de Sitter space, are basic in different cosmological and theoretical developments. It is also well known that complex structures admit metrics of this type. The most famous example is the complex projective space endowed with the Fubini-Study metric. In this work, we perform a systematic study of Einstein complex geometries derived from a logarithmic Kähler potential. Depending on the different contribution to the argument of such logarithmic term, we shall distinguish among direct, inverted and hybrid coordinates. They are directly related to the signature of the metric and determine the maximum domain of the complex space where the geometry can be defined.

An Einstein manifold in four dimensions has some configuration of $SU(2{)}_{+}$ Yang-Mills instantons and $SU(2{)}_{-}$ anti-instantons associated with it. This fact is based on the fundamental theorems that the four-dimensional Lorentz group Spin(4) is a direct product of two groups $SU(2{)}_{\pm }$ and the vector space of 2-forms decomposes into the space of self-dual and anti-self-dual 2-forms. It explains why the four-dimensional spacetime is special for the stability of Einstein manifolds. We now consider whether such a stability of four-dimensional Einstein manifolds can be lifted to a five-dimensional Einstein manifold. The higher-dimensional embedding of four-manifolds from the viewpoint of gauge theory is similar to the grand unification of the Standard Model, since the group $SO(4)\cong \mathrm{Spin}(4)/{\mathbb{Z}}_2=SU(2{)}_{+}\otimes SU(2{)}_{-}/{\mathbb{Z}}_2$ must be embedded into the simple group $SO(5)=Sp(2)/{\mathbb{Z}}_2$. Our group-theoretic approach reveals the anatomy of Riemannian manifolds quite similar to the quark model of hadrons in which two independent Yang-Mills instantons represent a substructure of Einstein manifolds.

In Newtonian physics or in general relativity, energy dissipation causes observers moving along circular orbits to slowly spiral toward the source of the gravitational field. We show that the loss of energy has the same effect in any theory of gravity respecting the weak equivalence principle, by exhibiting an intimate relation between the energy of a massive test particle and the stability of its orbit. Ultimately, massive particles either plunge, or are driven towards minima of the generalized Newtonian potential, where they become static. In addition, we construct a toy metric which displays an unbound innermost stable circular orbit, allowing particles that reach this orbit to be expelled away.

New early dark energy (NEDE) makes the cosmic microwave background consistent with a higher value of the Hubble constant inferred from supernovae observations. It is a better alternative to the old EDE model because it explains naturally the decay of the extra energy component in terms of a vacuum first-order phase transition that is triggered by a subdominant scalar field at zero temperature. With hot NEDE, we introduce a new mechanism to trigger the phase transition. It relies on thermal corrections that subside as a subdominant radiation fluid in a dark gauge sector cools. We explore the phenomenology of hot NEDE and identify the strong supercooled regime as the scenario favored by phenomenology. In a second step, we propose different microscopic embeddings of hot NEDE. This includes the (non-)Abelian dark matter model, which has the potential to also resolve the LSS tension through interactions with the dark radiation fluid. We also address the coincidence problem generically present in EDE models by relating NEDE to the mass generation of neutrinos via the inverse seesaw mechanism. We finally propose a more complete dark sector model, which embeds the NEDE field in a larger symmetry group and discuss the possibility that the hot NEDE field is central for spontaneously breaking lepton number symmetry.

Understanding the physics of inflaton condensate fragmentation in the early Universe is crucial as the existence of fragments in the form of nontopological solitons (oscillons or Q-balls) may potentially modify the evolution of the postinflation Universe. Furthermore, such fragments may evolve into primordial black holes and form dark matter, or emit gravitational waves. Due to the nonperturbative and nonlinear nature of the dynamics, most of the studies rely on numerical lattice simulations. Numerical simulations of condensate fragmentation are, however, challenging and, without knowing where to look in the parameter space, they are likely to be time-consuming as well. In this paper, we provide generic analytical conditions for the perturbations of an inflaton condensate to undergo growth to nonlinearity in the cases of both symmetric and asymmetric inflaton potentials. We apply the conditions to various inflation models and demonstrate that our results are in good agreement with explicit numerical simulations. Our analytical conditions are easy to use and may be utilized in order to quickly identify models that may undergo fragmentation and determine the conditions under which they do so, which can guide subsequent in-depth numerical analyses.

The scattering of cosmic microwave background (CMB) radiation in galaxy clusters induces polarization signals according to the quadrupole anisotropy in the photon distribution at the cluster location. This “remote quadrupole” derived from the measurements of the induced polarization provides an opportunity for reconstructing primordial fluctuations on large scales. We discuss that comparing the local CMB quadrupoles predicted by these reconstructed primordial fluctuations and the direct measurements done by CMB satellites may enable us to test the dark energy beyond cosmic variance limits.

There is much debate about the channels for astrophysical origins of the stellar-mass binary black hole (BBH) mergers detected by LIGO and Virgo. Active galactic nuclei (AGNs) are promising sites for the efficient formation and rapid mergers of BBHs due to migration traps in high-density gas disks within an inner radii. In this paper, we carry out Monte Carlo simulations to explore the mass properties of mergers over time and hierarchical mergers—with one of the black holes (BHs) being the remnant of a previous merger. We find that the predicted merger rate is $\sim 27–37{\mathrm{Gpc}}^{-3}{\mathrm{yr}}^{-1}$ and the detection rate of LIGO/Virgo accompanying with extreme mass-ratio mergers will increase in the late stage of AGNs. The fraction of hierarchical mergers is $\sim 24\%$, and its mass-ratio peak is $\sim 0.15–0.35$. Compared with the low-generation mergers in hierarchical mergers, the mass ratio of high-generation mergers has a flatter distribution around its peak. These reveal that the BBH mergers detected by LIGO/Virgo with the extreme mass ratio or heavy component masses can be well explained in the AGN channel.

Quantum fields in time-dependent backgrounds generally lead to particle production. Here we consider “unexciting” backgrounds for which the net particle production vanishes. We start by considering the simple harmonic oscillator and explicitly construct all unexciting time-dependent frequencies. This allows us to construct homogeneous backgrounds in field theory for which there is no particle production in any given mode, though we are able to show that there are no homogeneous backgrounds for which the particle production vanishes in every mode. We then construct general inhomogeneous unexciting field theory backgrounds. The set of all unexciting field theory backgrounds will be further restricted by the choice of physical interactions and this leads to an interesting open problem.

Minimal extensions of the Standard Model (SM), such as the so-called two-Higgs-doublet model (2HDM), can possess several accidental discrete symmetries whose spontaneous breakdown in the early Universe usually lead to the formation of domain walls. We extend an earlier work [R. A. Battye et al., J. High Energy Phys. 01 (2021) 105.] on this topic by studying in more detail the analytic properties of electrically charged and $CP$-violating kink solutions in the $Z_2$-symmetric 2HDM. We derive the complete set of equations of motion that describe the 1D spatial profile of both the 2HDM vacuum parameters and the would-be Goldstone bosons $G^{1,2,3}$ of the SM. These equations are then solved numerically using the gradient flow technique, and the results of our analysis are presented in different parametrizations of the Higgs doublets. In particular, we show analytically how an electrically charged profile should arise in 1D kink solutions when asymmetric boundary conditions are imposed on the Goldstone mode $G^2$ at spatial infinities, i.e. as $x\to \pm \infty$. If asymmetric boundary conditions are selected at $x\to \pm \infty$ for the Goldstone mode $G^3$ or the longitudinal mode $\theta$ corresponding to a would-be massive photon, the derived kink solutions are then shown to exhibit $CP$ violation. Possible cosmological implications of the electrically charged and $CP$-violating domain walls in the 2HDM are discussed.

A semirelativistic potential model is adopted to calculate the mass spectra of charmed and charmed-strange meson states up to the $2D$ excitations. The strong decay properties are further analyzed with a chiral quark model by using the numerical wave functions obtained from the potential model. By using the strong decay amplitudes extracted from the chiral quark model, we also systematically study the coupled-channel effects on the bare masses of the $1P$-wave states, since the masses of $D_{s0}^{*}(2317)$ and $D_{s1}(2460)$ cannot be explained with bare $1P$-wave states within the potential model. Based on our good descriptions of the mass and decay properties for the low-lying well-established states, we give a quark model classification for the high-mass resonances observed in recent years. In the $D$-meson family, $D_0(2550)$ can be classified as the radially excited state $D(2{{}^{1}S}_0)$, $D_3^{*}(2750)$ and $D_2(2740)$ can be classified as the second orbital excitations $D(1{{}^{3}D}_3)$ and $D(1D_2^{\prime })$, respectively, $D_J^{*}(3000)$ may be a candidate of $D(1{{}^{3}F}_4)$ or $D(2{{}^{3}P}_2)$, while $D_J(3000)$ may favor the high-mass mixed state $D(2P_1^{\prime })$; however, there are still puzzles in our understanding of the nature of $D_1^{*}(2600)$ and $D_1^{*}(2760)$, whose decay properties cannot be well explained with either pure $D(2{{}^{3}S}_1)$ and $D(1{{}^{3}D}_1)$ states or their mixing. In the $D_s$-meson family, $D_{s3}^{*}(2860)$ favors the $D_s(1{{}^{3}D}_3)$ assignment, $D_{s1}^{*}(2700)$ and $D_{s1}^{*}(2860)$ may favor the mixed states $|(SD{)}_1{⟩}_L$ and $|(SD{)}_1{⟩}_H$ via the $2{{}^{3}S}_1\text{−}1{{}^{3}D}_1$ mixing, respectively, $D_{sJ}(3040)$ may favor $D_s(2P_1)$ or $D_s(2P_1^{\prime })$, or correspond to a structure contributed by both $D_s(2P_1)$ and $D_s(2P_1^{\prime })$, the newly observed resonance $D_{s0}(2590{)}^{+}$ as an assignment of $D_s(2{{}^{1}S}_0)$, by including coupled-channel effects the mass of $D_s(2{{}^{1}S}_0)$ is close to the observed value; however, the width cannot be well understood in the present study. Many missing excited $D$- and $D_s$-meson states have a relatively narrow width and they are most likely to be observed in their dominant decay channels in future experiments.

The significant neutrino flux at high rapidity at the LHC motivates dedicated forward detectors to study the properties of neutrinos at TeV energies. We investigate magnetic dipole interactions between the active neutrinos and new sterile states at emulsion and liquid argon experiments that could be located in a future Forward Physics Facility (FPF) downstream of the ATLAS interaction point. The up-scattering of neutrinos off electrons produces an electron recoil signature that can probe new regions of parameter space at the High Luminosity LHC (HL-LHC), particularly for liquid argon detectors due to low momentum thresholds. We also consider the decay of the sterile neutrino through the dipole operator, which leads to a photon that could be displaced from the production vertex. FPF detectors can test sterile neutrino states as heavy as 1 GeV produced through the dipole portal, highlighting the use of high energy LHC neutrinos as probes of new physics.

We discuss the interplay of wave packet decoherence and decoherence induced by quantum gravity via interactions with spacetime foam for high-energy astrophysical neutrinos. In this context, we point out a compelling consequence of the expectation that quantum gravity should break global symmetries, namely that quantum-gravity induced decoherence may not only be the most sensitive probe for quantum properties of spacetime but also can provide both a powerful tool for the search for new particles, including totally decoupled backgrounds interacting only gravitationally, and at the same time a window into the intricacies of black hole information processing.

Using lattice QCD, we calculate the twist-2 contribution $a_2$ to the third Mellin moment of the spin structure functions $g_1$ and $g_2$ in the nucleon. In addition we evaluate the twist-3 contribution $d_2$. Our computations make use of $N_f=2+1$ gauge field ensembles generated by the Coordinated Lattice Simulations effort. Neglecting quark-line disconnected contributions we obtain as our best estimates $a_2^{(p)}=0.069(17)$, $d_2^{(p)}=0.0105(68)$ and $a_2^{(n)}=0.0068(88)$, $d_2^{(n)}=-0.0009(70)$ for the proton and the neutron, respectively, where we use the normalizations given in Eqs. (58) and (59). While the $a_2$ results have been converted to the $\overline{\mathrm{MS}}$ scheme using three-loop perturbation theory, the numbers for $d_2$ are given in the regularization independent momentum subtraction scheme, i.e., the conversion has been performed only in tree-level perturbation theory. The $d_2$ results can be interpreted as corresponding to a transverse color Lorentz force on a quark in a transversely polarized proton of size $F^{(u)}=116(61)$ and $F^{(d)}=-38(66)\mathrm{MeV}/\mathrm{fm}$ for $u$ and $d$ quarks, respectively. The error estimates quoted include statistical and systematic uncertainties added in quadrature.

Building upon the most recent CT18 global fit, we present a new calculation of the photon content of the proton based on an application of the LUX formalism. We explore two principal variations of the LUX ansatz. In one approach, which we designate “CT18lux,” the photon parton distribution function (PDF) is calculated directly using the LUX formula for all scales, $\mu$. In an alternative realization, “CT18qed,” we instead initialize the photon PDF in terms of the LUX formulation at a lower scale, $\mu \sim {\mu }_0$, and evolve to higher scales with a combined $\mathrm{QED}+\mathrm{QCD}$ kernel at $\mathcal{O}(\alpha ),\mathcal{O}(\alpha {\alpha }_s)$, and $\mathcal{O}({\alpha }^2)$. While we find that these two approaches generally agree, especially at intermediate $x$ (${10}^{-3}\lesssim x\lesssim 0.3$), we discuss some moderate discrepancies that can occur toward the end-point regions at very high or low $x$. We also study effects that follow from variations of the inputs to the LUX calculation originating outside the pure deeply inelastic scattering region, including from elastic form factors and other contributions to the photon PDF. Finally, we investigate the phenomenological implications of these photon PDFs for the LHC, including high-mass Drell-Yan measurements, vector-boson pairs, top-quark pairs, and Higgs bosons associated with vector-boson production.

The NEWS-G collaboration uses spherical proportional counters (SPCs) to search for weakly interacting massive particles (WIMPs). In this paper, we report the first measurements of the nuclear quenching factor in neon gas at 2 bar using an SPC deployed in a neutron beam at the TUNL facility. The energy-dependence of the nuclear quenching factor is modeled using a simple power law: $\alpha {\mathrm{E}}_{\mathrm{nr}}^{\beta }$; we determine its parameters by simultaneously fitting the data collected with the detector over a range of energies. We measured the following parameters in $\mathrm{Ne}:{\mathrm{CH}}_4$ at 2 bar: $\alpha =0.2801\pm 0.0050$ (fit) $\pm 0.0045$ (sys) and $\beta =0.0867\pm 0.020$ (fit) $\pm 0.006$ (sys). Our measurements do not agree with expected values from SRIM or Lindhard theory. We demonstrated the feasibility of performing quenching factor measurements at sub-keV energies in gases using SPCs and a neutron beam.

We revisit quantum field theory anomalies, emphasizing the interplay with diffeomorphisms and supersymmetry. The Ward identities of the latter induce Noether currents of all continuous symmetries, and we point out how these consistent currents are replaced by their covariant form through the appearance of the Bardeen-Zumino currents, which play a central role in our study. For supersymmetry Ward identities, two systematic methods for solving the Wess-Zumino consistency conditions are discussed: anomaly inflow and anomaly descent. The simplest inflows are from supersymmetric Chern-Simons actions in one dimension higher, which are used to supersymmetrize flavor anomalies in $d=4$ and, for $d=2$ $\mathcal{N}=(p,q)$, flavor anomalies with $p$, $q\le 3$ and Lorentz-Weyl anomalies with $p$, $q\le 6$. Finally, we extend the Becchi-Rouet-Stora-Tyutin algebra and the subsequent descent, a necessity for the diffeomorphism anomaly in retrospect. The same modification computes the supersymmetrized anomalies and determines the above Chern-Simons actions when these exist.

We consider gravitational lensing under a weak-field approximation and in a strong deflection limit by a Bronnikov-Kim wormhole with the same metric as the one of a wormhole which has been suggested in Einstein-Dirac-Maxwell theory. The metric approaches into the metric of an extreme charged Reissner-Nordström black hole in a black hole limit and it becomes the metric of a spatial Schwarzschild wormhole in an ultrastatic limit. In both of the black hole limit and the ultrastatic limit, the coefficient of a divergent term and the constant term of the deflection angle of a light in the strong deflection limit can be obtained exactly without expanding parameters of the spacetime. Interestingly, in the both limits to the black hole and the ultrastatic wormhole, we obtain exactly the same coefficient and constant term in the strong deflection limit.