We estimate the expected precision at a multi-TeV muon collider for measuring the Higgs boson couplings with electroweak gauge bosons, $HVV$ and $HHVV(V=W^{\pm },Z)$, as well as the trilinear Higgs self-coupling $HHH$. At very high energies both single and double Higgs productions rely on the vector-boson fusion (VBF) topology. The outgoing remnant particles have a strong tendency to stay in the very forward region, leading to the configuration of the “inclusive process” and making it difficult to isolate $ZZ$ fusion events from the $WW$ fusion. In the single Higgs channel, we perform a maximum likelihood analysis on $HWW$ and $HZZ$ couplings using two categories: the inclusive Higgs production and the 1-muon exclusive signal. In the double Higgs channel, we consider the inclusive production and study the interplay of the trilinear $HHH$ and the quartic $VVHH$ couplings, by utilizing kinematic information in the invariant mass spectrum. We find that at a center-of-mass energy of 10 TeV (30 TeV) with an integrated luminosity of $10{\mathrm{ab}}^{-1}$ ($90{\mathrm{ab}}^{-1}$), one may reach a 95% confidence level sensitivity of 0.073% (0.023%) for $WWH$ coupling, 0.61% (0.21%) for $ZZH$ coupling, 0.62% (0.20%) for $WWHH$ coupling, and 5.6% (2.0%) for $HHH$ coupling. For dim-6 operators contributing to the processes, these sensitivities could probe the new physics scale $\mathrm{\Lambda }$ in the order of 1–10 (2–20) TeV at a 10 TeV (30 TeV) muon collider.

Using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of $8.5{\mathrm{fb}}^{-1}$, the observation of a new excited ${\mathrm{\Xi }}_b^0$ resonance decaying to the ${\mathrm{\Xi }}_b^{-}{\pi }^{+}$ final state is presented. The state, referred to as ${\mathrm{\Xi }}_b(6227{)}^0$, has a measured mass and natural width of $m({\mathrm{\Xi }}_b(6227{)}^0)=6227.1_{-1.5}^{+1.4}\pm 0.5\mathrm{MeV}$ and $\mathrm{\Gamma }({\mathrm{\Xi }}_b(6227{)}^0)=18.6_{-4.1}^{+5.0}\pm 1.4\mathrm{MeV}$, where the uncertainties are statistical and systematic. The production rate of the ${\mathrm{\Xi }}_b(6227{)}^0$ state relative to that of the ${\mathrm{\Xi }}_b^{-}$ baryon in the kinematic region $2<\eta <5$ and $p_{\mathrm{T}}<30\mathrm{GeV}$ is measured to be $\frac{f_{{\mathrm{\Xi }}_b(6227{)}^0}}{f_{{\mathrm{\Xi }}_b^{-}}}\mathcal{B}({\mathrm{\Xi }}_b(6227{)}^0\to {\mathrm{\Xi }}_b^{-}{\pi }^{+})=0.045\pm 0.008\pm 0.004,$ where $\mathcal{B}({\mathrm{\Xi }}_b(6227{)}^0\to {\mathrm{\Xi }}_b^{-}{\pi }^{+})$ is the branching fraction of the decay, and $f_{{\mathrm{\Xi }}_b(6227{)}^0}$ and $f_{{\mathrm{\Xi }}_b^{-}}$ represent fragmentation fractions. Improved measurements of the mass and natural width of the previously observed ${\mathrm{\Xi }}_b(6227{)}^{-}$ state, along with the mass of the ${\mathrm{\Xi }}_b^{-}$ baryon, are also reported. Both measurements are significantly more precise than, and consistent with, previously reported values.

In this work we present a systematic study of ${\mathrm{AdS}}_{d+1}$ loop amplitudes for gluons and gravitons using momentum space techniques. Inspired by the recent progress in tree-level computation, we construct a differential operator that can act on a scalar factor in order to generate gluon and graviton loop integrands: this systematizes the computation for any given loop level Witten diagram. We then give a general prescription in this formalism, and discuss it for bubble, triangle, and box diagrams.

We study linear scalar perturbations of black holes in two-dimensional (2D) gravity models with a particular emphasis on Jackiw-Teitelboim (JT) gravity. We obtain an exact expression of the quasinormal mode frequencies for single horizon black holes in JT gravity and then verify it numerically using the Horowitz-Hubeny method. For a 2D Reissner-Nordström like solution, we find that the massless scalar wave equation reduces to the confluent Heun equation using which we calculate the Hawking spectra. Finally, we consider the dimensionally reduced Bañados-Teitelboim-Zanelli (BTZ) black hole and obtain the exterior and interior quasinormal modes. The dynamics of a scalar field near the Cauchy horizon mimics the behavior of the same for the usual BTZ black hole, indicating a possible violation of the strong cosmic censorship conjecture in the near extreme limit. However, quantum effects seem to rescue strong cosmic censorship.

In this paper we study the motion of photons or massless particles in the $C$ metric with cosmological constant. The Hamilton-Jacobi equations are known to be completely separable, giving a Carter-like quantity $Q$ which is a constant of motion. All possible trajectories are classified according to a two-dimensional parameter space representing the particle’s angular momentum and energy scaled in units of $Q$. Exact solutions are given in the $C$ metric coordinates in terms of Jacobi elliptic functions. Using the exact solutions, we find examples of periodic orbits on the photon surface.

We study the time evolution of the test scalar and electromagnetic fields perturbations in configurations of phantom wormholes surrounded by dark energy with state parameter $\omega <-1$. We observe obvious signals of echoes reflecting wormholes properties and disclose the physical reasons behind such phenomena. In particular, we find that the dark energy equation of state has a clear imprint in echoes in wave perturbations. When $\omega$ approaches the phantom divide $\omega =-1$ from below, the delay time of echoes becomes longer. The echo of gravitational wave is likely to be detected in the near future, and the signature of the dark energy equation of state in the echo spectrum can serve as a local measurement of the dark energy.

A fuzzy dark matter halo consists of a soliton core close to the center and a Navarro-Frenk-White–like density profile in the outer region. Previous investigations found that the soliton core exhibits temporal oscillations and random walk excursions around the halo center. Analyzing a set of numerical simulations, we show that both phenomena can be understood as the results of wave interference—a suitable superposition of the ground (solitonic) state and excited states in a fixed potential suffices to account for the main features of these phenomena. Such an eigenmode analysis can shed light on the evolution of a satellite halo undergoing tidal disruption. As the outer halo is stripped away, reducing the amplitudes of the excited states, the ground state evolves adiabatically. This suggests diminished soliton oscillations and random walk excursions, an effect to consider in deducing constraints from stellar heating.

We present limits on the parameters of the $\mathrm{o}\mathrm{\Lambda }\mathrm{CDM}$, $w_0\mathrm{CDM}$, and $w_0{w}_a\mathrm{CDM}$ models obtained from the joint analysis of the full-shape, baryon acoustic oscillations (BAO), big bang nucleosynthesis (BBN) and supernovae data. Our limits are fully independent of the data on the cosmic microwave background (CMB) anisotropies, but rival the CMB constraints in terms of parameter error bars. We find the spatial curvature consistent with a flat universe ${\mathrm{\Omega }}_k=-{0.043}_{-0.036}^{+0.036}$ (68% C.L.); the dark-energy equation of state parameter $w_0$ is measured to be $w_0=-{1.031}_{-0.048}^{+0.052}$ (68% C.L.), consistent with a cosmological constant. This conclusion also holds for the time-varying dark energy equation of state, for which we find $w_0=-{0.98}_{-0.11}^{+0.099}$ and $w_a=-{0.33}_{-0.48}^{+0.63}$ (both at 68% C.L.). The exclusion of the supernovae data from the analysis does not significantly weaken our bounds. This shows that using a single external BBN prior, the full-shape and BAO data can provide strong CMB-independent constraints on the nonminimal cosmological models.

We present a next-to-next-to-leading (fifth or NNLO) order calculation for the covariance matrix of the matter power spectrum, taking into account the effect of survey window functions. Using the grid-based calculation scheme for the standard perturbation theory, GridSPT, we quickly generate multiple realizations of the nonlinear density fields to fifth order in perturbation theory, then estimate the power spectrum and the covariance matrix from the sample. To the end, we have obtained the non-Gaussian covariance originated from the one-loop trispectrum without explicitly computing the trispectrum. By comparing the GridSPT calculations with the $N$-body results, we show that NNLO GridSPT result reproduces the $N$-body results on quasilinear scales, where SPT accurately models nonlinear matter power spectrum. Incorporating the survey window function effect to GridSPT is rather straightforward, and the resulting NNLO covariance matrix also matches well with the $N$-body results.

The optical design of the Einstein Telescope (ET) is based on a dual-recycled Michelson interferometer with Fabry-Perot cavities in the arms. ET will be constructed in a new infrastructure, allowing us to consider different technical implementations beyond the constraints of the current facilities. In this paper we investigate the feasibility of using beam-expander telescopes in the interferometer arms. We provide an example implementation that matches the optical layout as presented in the ET design update 2020. We further show that the beam-expander telescopes can be tuned to compensate for mode mismatches between the arm cavities and the rest of the interferometer.

The choked accretion model consists of a purely hydrodynamical mechanism in which, by setting an equatorial to polar density contrast, a spherically symmetric accretion flow transitions to an inflow-outflow configuration. This scenario has been studied in the case of a (nonrotating) Schwarzschild black hole as central accretor, as well as in the nonrelativistic limit. In this article, we generalize these previous works by studying the accretion of a perfect fluid onto a (rotating) Kerr black hole. We first describe the mechanism by using a steady-state, irrotational analytic solution of an ultrarelativistic perfect fluid, obeying a stiff equation of state. We then use hydrodynamical numerical simulations in order to explore a more general equation of state. Analyzing the effects of the black hole’s rotation on the flow, we find in particular that the choked accretion inflow-outflow morphology prevails for all possible values of the black hole’s spin parameter, showing the robustness of the model.

We develop a method to compute low-eccentricity initial data of black hole–neutron star binaries in the puncture framework extending previous work on other types of compact binaries. In addition to adjusting the orbital angular velocity of the binary, the approaching velocity of a neutron star is incorporated by modifying the helical Killing vector used to derive equations of the hydrostationary equilibrium. The approaching velocity of the black hole is then induced by requiring the vanishing of the total linear momentum of the system, differently from the case of binary black holes in the puncture framework where the linear momentum of each black hole is specified explicitly. We successfully reduce the orbital eccentricity to $\lesssim 0.001$ by modifying the parameters iteratively using simulations of $\approx 3$ orbits both for nonprecessing and precessing configurations. We find that empirical formulas for binary black holes derived in the excision framework do not reduce the orbital eccentricity to $\approx 0.001$ for black hole–neutron star binaries in the puncture framework, although they work for binary neutron stars.

Scattering processes in laser backgrounds are degenerate to the emission of unobservable photons collinear with the laser. We identify processes and observables for which such degeneracies factorize and exponentiate, obtaining the leading-order intensity dependence of these inclusive observables at high laser intensity, correct to all orders in the fine-structure constant (all loops, all emissions). The results show an exponential intensity dependence distinct from that predicted by the Narozhny-Ritus conjecture on the high-intensity behavior of quantum electrodynamics in strong fields.

In the modular invariant flavor model of ${\mathrm{A}}_4$, we study the hierarchical structure of lepton/quark flavors at nearby fixed points of $\tau =i$ and $\tau =\omega$ of the modulus, which are in the fundamental domain of $\mathrm{PSL}(2,\mathbb{Z})$. These fixed points correspond to the residual symmetries ${\mathbb{Z}}_2^S=\{I,S\}$ and ${\mathbb{Z}}_3^{ST}=\{I,ST,(ST{)}^2\}$ of ${\mathrm{A}}_4$, where $S$ and $T$ are generators of the $A_4$ group. The infinite $\tau =i\infty$ also preserves the residual symmetry of the subgroup ${\mathbb{Z}}_3^T=\{I,T,T^2\}$ of ${\mathrm{A}}_4$. We study typical two-type mass matrices for charged leptons and quarks in terms of modular forms of weights 2, 4, and 6, while the neutrino mass matrix with the modular forms of weight 4 through the Weinberg operator. Linear modular forms are obtained approximately by performing Taylor expansion of modular forms around fixed points. By using them, the flavor structure of the lepton and quark mass matrices are examined at nearby fixed points. The hierarchical structure of these mass matrices is clearly shown in the diagonal base of $S$, $T$, and $ST$. The observed Pontecorvo-Maki-Nakagawa-Sakata and Cabibbo-Kobayashi-Maskawa mixing matrices can be reproduced at nearby fixed points in some cases of mass matrices. By scanning model parameters numerically at nearby fixed points, our discussion are confirmed for both the normal hierarchy and the inverted one of neutrino masses. Predictions are given for the sum of neutrino masses and the $CP$ violating Dirac phase of leptons at each nearby fixed point.

Composite Higgs models must exhibit very different dynamics from quantum chromodynamics (QCD) regardless whether they describe the Higgs boson as a dilatonlike state or a pseudo-Nambu-Goldstone boson. Large separation of scales and large anomalous dimensions are frequently desired by phenomenological models. Mass-split systems are well-suited for composite Higgs models because they are governed by a conformal fixed point in the ultraviolet but are chirally broken in the infrared. In this work we use lattice field theory calculations with domain wall fermions to investigate a system with four light and six heavy flavors. We demonstrate how a nearby conformal fixed point affects the properties of the four light flavors that exhibit chiral symmetry breaking in the infrared. Specifically we describe hyperscaling of dimensionful physical quantities and determine the corresponding anomalous mass dimension. We obtain $y_m=1+{\gamma }^{*}=1.47(5)$ suggesting that $N_f=10$ lies inside the conformal window. Comparing the low energy spectrum to predictions of dilaton chiral perturbation theory, we observe excellent agreement which supports the expectation that the $4+6$ mass-split system exhibits near-conformal dynamics with a relatively light $0^{++}$ isosinglet scalar.

We simulate the $3+1$-dimensional classical Yang-Mills dynamics of the collisions of longitudinally extended nuclei, described by eikonal color charges in the color glass condensate framework. By varying the longitudinal thickness of the colliding nuclei, we discuss the violations of boost invariance and explore how the boost-invariant high-energy limit is approached. Subsequently, we develop a more realistic model of the three-dimensional color charge distributions that connects longitudinal and transverse fluctuations to the $x$ and ${\mathbf{k}}_{\perp }$ dependence of transverse momentum dependent parton distributions and explore the resulting rapidity profiles and their longitudinal fluctuations.

We present a study of the normalized transverse momentum distribution of $W$ bosons produced in $p\overline{p}$ collisions, using data corresponding to an integrated luminosity of $4.35{\mathrm{fb}}^{-1}$ collected with the D0 detector at the Fermilab Tevatron collider at $\sqrt{s}=1.96\mathrm{TeV}$. The measurement focuses on the transverse momentum region below 15 GeV, which is of special interest for electroweak precision measurements; it relies on the same detector calibration methods which were used for the precision measurement of the $W$ boson mass. The measured distribution is compared to different QCD predictions and a procedure is given to allow the comparison of any further theoretical models to the D0 data.

We numerically study the topologically twisted index of several three-dimensional supersymmetric field theories on a genus $g$ Riemann surface times a circle, ${\mathrm{\Sigma }}_g\times S^1$. We show that for a large class of theories with leading term of the order $N^{3/2}$, where $N$ is generically the rank of the gauge group, there is a universal logarithmic correction of the form $\frac{g-1}{2}\log N$. We explain how this logarithmic subleading correction can be obtained as a one-loop effect on the dual supergravity theory for magnetically charged, asymptotically ${\mathrm{AdS}}_4\times M^7$ black holes for a large class of Sasaki-Einstein manifolds, $M^7$. The matching of the logarithmic correction relies on a generic cohomological property of $M^7$ and it is independent of the black hole charges. We argue that our supergravity results apply also to rotating, electrically charged asymptotically ${\mathrm{AdS}}_4\times M^7$ black holes. We present explicitly the quiver gauge theories and the gravity side corresponding to $M^7=N^{0,1,0},V^{5,2}$ and $Q^{1,1,1}$.

We obtain a simple relationship between the change in the Brown-York energy inside a closed two-surface just outside of a horizon of spacetime, and the change in the area of that two-surface.

We derive the static Schwarzschild-Tangherlini metric by extracting the classical contributions from the multiloop vertex functions of a graviton emitted from a massive scalar field. At each loop order the classical contribution is proportional to a unique master integral given by the massless sunset integral. By computing the scattering amplitudes up to three-loop order in general dimension, we explicitly derive the expansion of the metric up to the fourth post-Minkowskian order $O(G_N^4)$ in four, five and six dimensions. There are ultraviolet divergences that are cancelled with the introduction of higher-derivative nonminimal couplings. The standard Schwarzschild-Tangherlini is recovered by absorbing their effects by an appropriate coordinate transformation induced from the de Donder gauge condition.