We provide results for the open-flavor strong decays of open-charm ($D$ and $D_{\mathrm{s}}$) and open-bottom ($B$, $B_{\mathrm{s}}$, and $B_{\mathrm{c}}$) mesons. The decays are calculated in a modified version of the ${}^3{P}_0$ pair-creation model, assuming harmonic oscillator wave functions. The spectra of open-charm and open-bottom mesons used in the calculations are computed within Godfrey and Isgur’s relativized quark model. Quantum number assignments are also provided. Our results are compared with the existing experimental data.

The measurement of triple Higgs coupling is a key benchmark for the Large Hadron Collider (LHC) and future colliders. It directly probes the Higgs potential and its fundamental properties in connection to new physics beyond the Standard Model. There exist two phase space regions with an enhanced sensitivity to the Higgs self-coupling, the Higgs pair production threshold, and an intermediate top pair threshold. We show how the invariant mass distribution of the Higgs pair offers a systematic way to extract the Higgs self-coupling, focusing on the leading channel $pp\to hh+X\to b\overline{b}\gamma \gamma +X$. We utilize new features of the signal events at higher energies and estimate the potential of a high-energy upgrade of the LHC and a future hadron collider with realistic simulations. We find that the high-energy upgrade of the LHC to 27 TeV would reach a $5\sigma$ observation with an integrated luminosity of $2.5{\mathrm{ab}}^{-1}$. It would have the potential to reach 15% (30%) accuracy at the 68% (95%) confidence level to determine the Standard Model (SM) Higgs boson self-coupling. A future 100 TeV collider could improve the self-coupling measurement to better than 5% (10%) at the 68% (95%) confidence level.

A theoretical description of the $g$ factor of a muon bound in a nuclear potential is presented. One-loop self-energy and multiloop vacuum polarization corrections are calculated, taking into account the interaction with the binding potential exactly. Nuclear effects on the bound-muon $g$ factor are also evaluated. We put forward the measurement of the bound-muon $g$ factor via the continuous Stern-Gerlach effect as an independent means to determine the muon’s magnetic moment anomaly and mass. The scheme presented enables the increase of the accuracy of the mass by more than an order of magnitude.

In this work we consider a two-dimensional quantum black hole sourced by the trace anomaly of a conformal field theory. By using holography, we are able to prove that the black hole size is always proportional to the number of states inside the black hole, a result that might be interpreted as a two-dimensional version of the Bekenstein entropy law. Finally, we also show that such a black hole has a minimal size (a remnant). Extrapolating this result for higher dimensions, we show that this would imply that the remnant has a size way larger than the Planck length and is, therefore, always weakly coupled.

We study supersymmetric Wilson loops in $d=3$, $\mathcal{N}=3$ harmonic superspace, leading to a construction of a supersymmetrized generalization of the $\frac{1}{3}$-BPS Wilson loop for $\mathcal{N}=3$ gauge theories. This also includes the generalization of the $\frac{1}{6}$-BPS loop for ABJM theory. We perform a “one-loop” computation of the vacuum expectation value of this operator directly in superspace and compare with the known $\mathcal{N}=2$ localization results at large $N$. This comparison also lets us identify certain fermionic contributions that do not receive any subleading corrections.

It is well known that the presence of a spacetime boundary requires the conventional Einstein-Hilbert action to be supplemented by the Gibbons-Hawking boundary term in order to retain the standard variational procedure. When the Einstein-Hilbert action is amended by the diffeomorphism-invariant graviton mass and potential terms, it naively appears that no further boundary terms are needed since all the new fields of massive gravity enter the action with the first derivative. However, we show that such a formulation would be inconsistent, even when the bulk action is ghost free. The theory is well defined only after introducing novel boundary counterterms, which dominate over the Gibbons-Hawking term in the massless limit and cancel the problematic boundary terms induced by the bulk action. The number of boundary counterterms equals the number of total derivatives one could construct in the bulk using positive powers of two derivatives of the longitudinal mode of the massive graviton.

We consider a quasi-single field inflation model in which the inflaton interacts with a massive scalar field called the isocurvaton. Due to the breaking of time translational invariance by the inflaton background, these interactions induce kinetic mixing between the inflaton and isocurvaton, which is parameterized by a constant $\mu$. We derive analytic formulas for the curvature perturbation two-, three-, four-, five-, and six-point functions explicitly in terms of the external wave vectors in the limit where $\mu$ and the mass of the isocurvaton $m$ are both much smaller than $H$. In previous work, it has been noted that when $m/H$ and $\mu /H$ are small, the non-Gaussianities predicted by quasi-single field inflation give rise to long wavelength enhancements of the power spectrum for biased objects (e.g., galactic halos). We review this calculation, and calculate the analogous enhanced contribution to the bispectrum of biased objects. We determine the scale at which these enhanced terms are larger than the Gaussian piece. We also identify the scaling of these enhanced parts to the $n$-point function of biased objects.

Pulsars have been invoked to explain the origin of recently observed high-energy Galactic cosmic-ray positrons. Since the positron propagation distance decreases with energy, the number of pulsars that can contribute to the observed positrons decreases from $O({10}^3)$ for positron energies $E\gtrsim 10\mathrm{GeV}$ to only a few for $E\gtrsim 500\mathrm{GeV}$. Thus, if pulsars explain these positrons, the positron energy spectrum should become increasingly bumpy at higher energies. Here, we present a power-spectrum analysis that can be applied to seek such spectral features in the energy spectrum for cosmic-ray positrons and for the energy spectrum of the combined electron/positron flux. We account for uncertainties in the pulsar distribution by generating hundreds of simulated spectra from pulsar distributions consistent with current observational constraints. Although the current AMS-02 data do not exhibit evidence for spectral features, we find that such features would be detectable at the $2\sigma$ lavel in $\simeq 10\%$ of our simulations, with 20 years of AMS-02 data or three years of DAMPE measurements on the electron-plus-positron flux.

The exclusive photoproduction of the heavy vector mesons $\psi$ and Y is investigated in peripheral Pb-Pb collisions for the energies available at the LHC, $\sqrt{s}=2.76\mathrm{TeV}$ and $\sqrt{s}=5.02\mathrm{TeV}$. To evaluate the robustness of the light-cone color dipole formalism, previously tested in the ultraperipheral regime, the rapidity distribution and the nuclear modification factor ($R_{AA}$) are calculated for the three centrality classes: 30%–50%, 50%–70%, and 70%–90%. The ultraperipheral to peripheral regime transition was carried out by sophisticating the photon flux description and the photonuclear cross section, taking into account the effective interaction area. In our calculations, three scenarios were considered: (scenario 1) the direct application of the usual photon flux and of the photonuclear cross section with no relevant change in relation to the ultraperipheral collision (UPCs), (scenario 2) the application of an effective photon flux keeping the photonuclear cross section unchanged, and (scenario 3) also considering an effective photonuclear cross section. The results obtained with the three different scenarios were compared with the ALICE measurements, showing a better agreement with the data (only $J/\psi$ at the moment) in the more complete approach (scenario 3), mainly in the more central regions (30%–50% and 50%–70%) where the uncertainty is smaller.

We propose a simple theory for the idea that cosmological dark matter (DM) may be present today mainly in the form of stable neutral hadronic thermal relics. In our model, neutrino masses arise radiatively from the exchange of colored DM constituents, giving a common origin for both dark matter and neutrino mass. The exact conservation of $B-L$ symmetry ensures dark matter stability and the Dirac nature of neutrinos. The theory can be falsified by dark matter nuclear recoil direct detection experiments, leading also to possible signals at a next generation hadron collider.

We present the first combined study of correlators and spectral properties of charmonium and open charm mesons at finite temperature using a fully relativistic lattice QCD approach. The QCD medium is captured by second generation anisotropic $24^3\times N_{\tau }$ lattices from the FASTSUM Collaboration, including $2+1$ flavors of clover discretized quarks with $m_{\pi }\approx 380\mathrm{MeV}$. Two Bayesian methods are deployed to reconstruct the spectral functions, the recent Bayesian reconstruction (BR) method as well as the maximum entropy method with Fourier basis. We take particular care to disentangle genuine in-medium effects from method artifacts with the help of the reconstructed correlator. Consistent with the direct inspection of correlators, we observe no significant in-medium modification for $J/\mathrm{\Psi }$ and ${\eta }_c$ around the crossover, while the ${\chi }_c$ states on the other hand show clear changes around the transition. At the highest temperature, $T=352\mathrm{MeV}$, $J/\mathrm{\Psi }$ and ${\eta }_c$ also exhibit discernible changes compared to the vacuum. For $D$ mesons around $T_c$, no significant modifications are observed, but we find clear indications that no bound state survives at the highest temperature of $T=352\mathrm{MeV}$. Above $T_c$ we discover a significant difference between $D$ and $D^{*}$ mesons, the latter being much more strongly affected by the medium.

A liquid argon time projection chamber, constructed for the Argon Response to Ionization and Scintillation (ARIS) experiment, is exposed to the highly collimated and quasimonoenergetic LICORNE neutron beam at the Institut de Physique Nucléaire d’Orsay (IPNO) in order to study the scintillation response to nuclear and electronic recoils. An array of liquid scintillator detectors, arranged around the apparatus, tag scattered neutrons and select nuclear recoil energies in the [7, 120] keV energy range. The relative scintillation efficiency of nuclear recoils is measured to high precision at null field, and the ion-electron recombination probability is extracted for a range of applied electric fields. Single-scattered Compton electrons, produced by gammas emitted from the deexcitation of ${}^7{\mathrm{Li}}^{*}$ in coincidence with the beam pulse, along with calibration gamma sources, are used to extract the recombination probability as a function of energy and electron drift field. The ARIS results are compared with three recombination probability parametrizations (Thomas-Imel, Doke-Birks, and PARIS), allowing for the definition of a fully comprehensive model of the liquid argon response to nuclear and electronic recoils down to the few-keV range. The constraints provided by ARIS to the liquid argon response at low energy allow the reduction of systematics affecting the sensitivity of dark matter search experiments based on liquid argon.

The generalized uncertainty principle is a phenomenological model whose purpose is to account for a minimal length in quantum and classical systems. However, the analysis of problems in classical physics is usually approached using a different formalism than the one used for quantum systems, and vice versa. Potentially, the two approaches can result in inconsistencies. Here, we eliminate such inconsistencies by proposing particular meanings and relations between the variables used to describe physical systems, resulting in a precise form of the Legendre transformation. Furthermore, we introduce two different sets of canonical variables and the relative map between them. These two sets allow for a complete and unambiguous description of classical and quantum systems.

We construct new solutions of the Faddeev-Skyrme-Maxwell model, which represent Hopf solitons coupled to magnetic fluxes. It turns out that coupling to the magnetic field allows for transmutations of the solitons; however, the results depend both on the type of the vacuum boundary condition and on the strength of the gauge coupling. It is shown that the structure of the magnetic fluxes of a gauged Hopfion is governed by the preimages of the points ${\varphi }_3=\pm 1$.

While recent detections of gravitational waves from the mergers of binary black holes match well with the predictions of General Relativity, they cannot directly confirm the existence of event horizons. Exotic compact objects are motivated by quantum models of black holes and can have exotic structure (or a “wall”) just outside the (would-be) horizon. Exotic compact objects produce ringdown waveforms similar to the General Relativistic black holes, but they are followed by delayed “echoes.” By solving linearized Einstein equations, we can model these echoes and provide analytic templates that can be used to compare to observations. For concreteness, we consider the GW150914 event, detected by the LIGO/Virgo Collaboration, and study the model dependence of its echo properties. We find that echoes are reasonably approximated by complex Gaussians, with amplitudes that decay as a power law in time, while their width in time (frequency) grows (shrinks) over subsequent echoes. We also show that trapped modes between a perfectly reflecting wall and angular momentum barrier in the Kerr metric can exhibit superradiant instability over long times, as expected.

In scalar-vector-tensor theories with $U(1)$ gauge invariance, it was recently shown that there exists a new type of hairy black hole (BH) solutions induced by a cubic-order scalar-vector interaction. In this paper, we derive conditions for the absence of ghosts and Laplacian instabilities against odd-parity perturbations on a static and spherically symmetric background for most general $U(1)$ gauge-invariant scalar-vector-tensor theories with second-order equations of motion. We apply those conditions to hairy BH solutions arising from the cubic-order coupling and show that the odd-parity stability in the gravity sector is always ensured outside the event horizon with the speed of gravity equivalent to that of light. We also study the case in which quartic-order interactions are present in addition to the cubic coupling and obtain conditions under which black holes are stable against odd-parity perturbations.

In this work we study the occurrence of finite-time cosmological singularities in a cosmological system comprising three fluids. Particularly, the system contains two dark fluids, namely, that of dark energy and dark matter, which are interacting, and of a noninteracting baryonic fluid. For the study we adopt the phase space approach by constructing the cosmological dynamical system in such a way that it is rendered as an autonomous polynomial dynamical system, and in order to achieve this, we appropriately choose the variables of the dynamical system. By employing a rigid mathematical framework, that of dominant balances analysis, we demonstrate that there exist nonsingular solutions of the dynamical system, which correspond to a general set of initial conditions, which proves that no big rip or type III finite-time singularities occur in this loop quantum cosmology multifluid dynamical system. Thus the new feature of this work is that we are able to do this using an analytic technique instead of adopting a numerical approach. In addition, we perform a fixed point analysis of the cosmological dynamical system, and we examine the behavior of the total effective equation of state parameter, at the fixed points, as a function of the free parameters of the system. Finally, we investigate the phenomenological implications of the dark energy equation of state, which we assumed governs the dark energy fluid.

We investigate the dynamics of a number of $f(R)$ theories in the background of the spatially homogeneous as well as isotropic Friedmann-Leimaître-Robertson-Walker (FLRW) model and anisotropic Bianchi type I and V models in Palatini formalism using the dynamical systems approach. Considering theories of the type $f(R)=R+\gamma R^m-\beta /R^n$, it is examined whether this model is capable of allowing all four phases of cosmological evolution or not. Additionally, we have performed the analysis for $f(R)=R+\gamma R^2$, as these theories have attracted great attention in recent years. For the theories of the type $f(R)=R-\beta /R^n$, the sequence of the radiation-dominated, matter-dominated, and accelerated expanding epochs has been reproduced. In the case of anisotropic models, the evolution of the anisotropy parameter, i.e., the shear, is also investigated, where it is found that the initial anisotropic Universe evolves to a stable accelerated expanding Universe. Moreover, corresponding to the Bianchi type V model, the evolution of spatial curvature is also investigated.

We consider the Horndeski theory in four-dimensional space-time as the most general theory with a single scalar field and second order field equations. We show that this theory does not admit stable, static, spherically symmetric, asymptotically flat, Lorentzian wormholes.

The gravitational wave radiation emitted by all, resolved and unresolved, astrophysical sources in the observable universe generates a stochastic background. This background has a directional dependence inherited from the inhomogeneities of the matter distribution. This article proposes a new and independent derivation of the angular dependence of its energy density by focusing on the total gravitational wave signal produced by an ensemble of incoherent sources. This approach clarifies the origin of the angular correlation and the relation between the gravitational wave signal that can be measured by interferometers and the energy density of the stochastic background.