We show that the leading coupling between a shift symmetric inflaton and the standard model fermions leads to an induced electroweak symmetry breaking due to particle production during inflation, and as a result, a unique oscillating feature in non-Gaussianities. In this one parameter model, the enhanced production of standard model fermions dynamically generates a new electroweak symmetry breaking minimum, where the Higgs field classically rolls to. The production of fermions stops when the Higgs expectation value and hence the fermion masses become too large, suppressing fermion production. The balance between the above-mentioned effects gives the standard model fermions masses that are uniquely determined by their couplings to the inflaton. In particular, the heaviest standard model fermion, the top quark, can produce a distinct cosmological collider physics signature characterized by a one-to-one relation between amplitude and frequency of the oscillating signal, which is observable at future 21-cm surveys.

We calculate the skewness (the third moment $S_3$) of matter distribution in dynamical dark energy cosmologies. We pay particular attention to the impact of dark energy perturbations on this quantity. There is indeed a clear signature of dark energy perturbations on this quantity. By properly allowing dark energy perturbations we show that their impact on $S_3$ is strong enough (a factor $\sim 3$ greater) to easily discriminate between clustering and nonclustering dark energy cosmologies. This indicates that high order statistics of the cosmic density field are useful to the study of dark energy models and are potentially able to rule out clustering dark energy cosmologies.

There are many possibilities of scenarios in the early universe, which can give rise to the same observational signals due to the degeneracy among each other, caused by equivalence under the conformal transformations. In order to break the degeneracy, in this paper we take into account the so-called “frame-invariant variables” proposed by A. Ijjas and P. J. Steinhardt in [J. Cosmol. Astropart. Phys. 10 (2015) 001]. We discuss how the different scenarios will distribute in different parametric space constructed from those variables, waiting for the judgement of real observations in the future. Several concrete models with explicit nonminimal coupling functions are also discussed.

Gravitational-wave memory, a strong-field effect of general relativity, manifests itself as a permanent displacement in spacetime. We develop a Bayesian framework to detect gravitational-wave memory with the Advanced LIGO/Virgo detector network. We apply this algorithm on the ten binary black hole mergers in LIGO/Virgo’s first transient gravitational-wave catalog. We find no evidence of memory, which is consistent with expectations. In order to estimate when memory will be detected, we use the best current population estimates to construct a realistic sample of binary black hole observations for LIGO/Virgo at design sensitivity. We show that an ensemble of $\mathcal{O}(2000)$ binary black hole observations can be used to find definitive evidence for gravitational-wave memory. We conclude that memory is likely to be detected in the early $A+/\mathrm{Virgo}+\mathrm{era}$.

Primordial black holes (PBHs) can represent all or most of the dark matter in the window ${10}^{17}–{10}^{22}\mathrm{g}$. Here we present an extension of the constraints on PBHs of masses ${10}^{13}–{10}^{18}\mathrm{g}$ arising from the isotropic diffuse gamma-ray background. Primordial black holes evaporate by emitting Hawking radiation that should not exceed the observed background. Generalizing from monochromatic distributions of Schwarzschild black holes to extended mass functions of Kerr rotating black holes, we show that the lower part of this mass window can be closed for near-extremal black holes.

Positivity bounds—the consequences of requiring a unitary, causal, local UV completion—place strong restrictions on theories of dark energy and/or modified gravity. We derive and investigate such bounds for Horndeski scalar-tensor theories and for the first time pair these bounds with a cosmological parameter estimation analysis, using CMB, redshift space distortion, matter power spectrum, and baryon acoustic oscillation measurements from the Planck, SDSS/BOSS, and 6dF surveys. Using positivity bounds as theoretical priors, we show that their inclusion in the parameter estimation significantly improves the constraints on dark energy/modified gravity parameters. Considering as an example a specific class of models, which are particularly well-suited to illustrate the constraining power of positivity bounds, we find that these bounds eliminate over 60% of the previously allowed parameter space. We also discuss how combining positivity requirements with additional theoretical priors has the potential to further tighten these constraints: for instance, also requiring a subluminal speed of gravitational waves eliminates all but $\lesssim 1\%$ of the previously allowed parameter space.

We study the thermodynamic geometry of the quark-meson model, focusing on the curvature, $R$, around the chiral crossover at finite temperature and baryon chemical potential. We find a peculiar behavior of $R$ in the crossover region, in which the sign changes and a local maximum develops; in particular, the height of the peak of $R$ in the crossover region becomes large in the proximity of the critical end point and diverges at the critical end point. The appearance of a pronounced peak of $R$ close to the critical end point supports the idea that $R$ grows with the correlation volume around the phase transition. Moreover, the change of sign of $R$ in the crossover region supports the idea that an attractive interaction develops at the mesoscopic level in that range of temperature. We also analyze the mixed fluctuations of energy and baryon number, $⟨\mathrm{\Delta }U\mathrm{\Delta }N⟩$, which grow up substantially in the proximity of the critical end point: In the language of thermodynamic geometry these fluctuations are responsible for the vanishing of the determinant of the metric, which results in thermodynamic instability and are thus related to the appearance of a critical end point.

Dark matter direct detection experiments have limited sensitivity to light dark matter (below a few GeV), due to the challenges of lowering energy thresholds for the detection of nuclear recoil to below $\mathcal{O}(\mathrm{keV})$. While impressive progress has been made on this front, light dark matter remains the least constrained region of dark-matter parameter space. It has been shown that both ionization and excitation due to the Migdal effect and coherently emitted photon bremsstrahlung from the recoiling atom can provide observable channels for light dark matter that would otherwise have been missed owing to the resulting nuclear recoil falling below the detector threshold. In this paper we extend previous work by calculating the Migdal effect and photon bremsstrahlung rates for a general set of interaction types, including those that are momentum independent or dependent, spin independent or dependent, as well as examining the rates for a variety of target materials, allowing us to place new experimental limits on some of these interaction types. Additionally, we include a calculation of these effects induced by the coherent scattering on nuclei of solar or atmospheric neutrinos. We demonstrate that the Migdal effect dominates over the bremsstrahlung effect for all targets considered for interactions induced by either dark matter or neutrinos. This reduces photon bremsstrahlung to irrelevancy for future direct detection experiments.

Motivated by the $R_{D^{(*)}}$ anomalies, we investigate an SO(10) grand unification scenario where a charge $-1/3$ scalar leptoquark ($S_1$) remains as the only new physics candidate at the TeV scale. This leptoquark along with the Standard Model (SM) Higgs doublet originates from the same ten-dimensional real scalar multiplet in the SO(10) grand unification framework taking its mass close to the electroweak scale. We explicitly show how the gauge coupling unification is achieved with only one intermediate symmetry-breaking scale at which the Pati-Salam gauge group is broken into the SM group. We investigate the phenomenological implications of our scenario and show that an $S_1$ with a specific Yukawa texture can explain the $R_{D^{(*)}}$ anomalies. We perform a multiparameter scan considering the relevant flavor constraints on $R_{D^{(*)}}$, $F_L(D^{*})$, $P_{\tau }(D^{*})$ and $R_{K^{(*)}}^{\nu \nu }$ as well as the constraint coming from the $Z\to \tau \tau$ decay and the latest $\tau \tau$ resonance search data at the LHC. Our analysis shows that a single leptoquark solution to the observed $R_{D^{(*)}}$ anomalies with $S_1$ is still a viable solution.

In this paper, we propose a framework for studying the properties of the Lefschetz thimbles decomposition for lattice fermion models approaching the thermodynamic limit. The proposed set of algorithms includes the Schur complement solver and the exact computation of the derivatives of the fermion determinant. It allows us to solve the gradient flow equations taking into account the fermion determinant exactly, with high performance. Being able to do so, we can find both real and complex saddle points and describe the structure of the Lefschetz thimbles decomposition for large enough lattices which allows us to extrapolate our results to the thermodynamic limit. We describe the algorithms for a general lattice fermion model, with emphasis on two widely used types of lattice discretizations for relativistic fermions (staggered and Wilson fermions), as well as on interacting tight-binding models for condensed matter systems. As an example, we apply these algorithms to the Hubbard model on a hexagonal lattice. Several technical improvements allow us to deal with lattice volumes as large as $12\times 12$ with $N_{\tau }=256$ steps in Euclidean time, in order to capture the properties of the thimbles decomposition as the thermodynamic, low-temperature, and continuum limits are approached. Different versions of the Hubbard-Stratonovich (HS) transformation were studied, and we show that the complexity of the thimbles decomposition is very dependent on its specific form. In particular, we provide evidence for the existence of an optimal regime for the hexagonal lattice Hubbard model, with a reduced number of thimbles becoming important in the overall sum. In order to check these findings, we have performed quantum Monte Carlo (QMC) simulations using the gradient flow to deform the integration contour into the complex plane. These calculations were made on small volumes ($N_s=8$ sites in space), albeit still at low temperatures and with the chemical potential tuned to the van Hove singularity, thus entering into a regime where standard QMC techniques exhibit an exponential decay of the average sign. The results are compared versus exact diagonalization, and we demonstrate the importance of choosing an optimal form for the HS transformation for the Hubbard model to avoid issues associated with ergodicity. We compare the residual sign problem with the state-of-the-art BSS (Blankenbecler, Scalapino, and Sugar)-QMC and show that the average sign can be kept substantially higher using the Lefschetz thimbles approach.

The valence double parton distribution of the pion is analyzed in the framework of chiral quark models, where in the chiral limit factorization between the longitudinal and transverse degrees of freedom occurs. This feature leads, at the quark-model scale, to a particularly simple distribution of the form $D(x_1,x_2,\mathit{q})=\delta (1-x_1-x_2)F(\mathit{q})$, where $x_{1,2}$ are the longitudinal momentum fractions carried by the valence quark and antiquark and $\mathit{q}$ is their relative transverse momentum. For $\mathit{q}=\mathbf{0}$ this result complies immediately with the Gaunt-Sterling sum rules. The Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution to higher scales is carried out in terms of the Mellin moments. We then explore its role on the longitudinal correlation quantified with the ratio of the double distribution to the product of single distributions, $D(x_1,x_2,\mathit{q}=\mathbf{0})/D(x_1)D(x_2)$. We point out that the ratios of moments $⟨x_1^n{x}_2^m⟩/⟨x_1^n⟩⟨x_2^m⟩$ are independent of the evolution, providing particularly suitable measures to be tested in the upcoming lattice simulations. The transverse form factor $F(\mathit{q})$ and its Fourier conjugate in the relative transverse coordinate $\mathit{b}$ are obtained in variants of the Nambu–Jona-Lasinio model with the spectral and Pauli-Villars regularizations. The results are valid in the soft-momentum domain. Interestingly, with the spectral regularization of the model, the effective cross section for the double parton scattering of pions is exactly equal to the geometric cross section, ${\sigma }_{\mathrm{eff}}=\pi ⟨{\mathit{b}}^2⟩$, and yields about 20 mb.

We study the structure of the ${\mathrm{\Lambda }}_c(2595)$ and ${\mathrm{\Lambda }}_c(2625)$ resonances in the framework of an effective field theory consistent with heavy quark spin and chiral symmetries, which incorporates the interplay between ${\mathrm{\Sigma }}_c^{(*)}\pi -N{D}^{(*)}$ baryon-meson degrees of freedom (d.o.f.) and bare $P$-wave $c\overline{u}d$ quark-model states. We show that these two resonances are not heavy quark spin symmetry partners. The $J^P=3/2^{-}$ ${\mathrm{\Lambda }}_c(2625)$ should be viewed mostly as a dressed three-quark state, whose origin is determined by a bare state, predicted to lie very close to the mass of the resonance. The $J^P=1/2^{-}$ ${\mathrm{\Lambda }}_c(2595)$ seems to have, however, a predominant molecular structure. This is because it is either the result of the chiral ${\mathrm{\Sigma }}_c\pi$ interaction, whose threshold is located much closer than the mass of the bare three-quark state, or because the light d.o.f. in its inner structure are coupled to the unnatural $0^{-}$ quantum numbers. We show that both situations can occur depending on the renormalization procedure used. We find some additional states, but the classification of the spectrum in terms of heavy quark spin symmetry is difficult, despite having used interactions that respect this symmetry. This is because the bare quark-model state and the ${\mathrm{\Sigma }}_c\pi$ threshold are located extraordinarily close to the ${\mathrm{\Lambda }}_c(2625)$ and ${\mathrm{\Lambda }}_c(2595)$, respectively, and hence they play totally different roles in each sector.

In this work, we perform a systematic study of the strong decays for the higher singly heavy baryon resonances ${\mathrm{\Lambda }}_Q(3S)$, ${\mathrm{\Lambda }}_Q(2P)$, ${\mathrm{\Lambda }}_Q(2D)$, ${\mathrm{\Lambda }}_Q(1F)$, ${\mathrm{\Sigma }}_Q(3S)$, ${\mathrm{\Sigma }}_Q(2P)$, ${\mathrm{\Sigma }}_Q(2D)$, and ${\mathrm{\Sigma }}_Q(1F)$ within the ${}^3{P}_0$ model. Our results show that most of the $\lambda$-mode higher excited ${\mathrm{\Lambda }}_Q$ and ${\mathrm{\Sigma }}_Q$ states have a relatively narrow width, and mainly decay into two-body final states with one heavy meson plus one light baryon. Our calculations provide abundant theoretical information and demonstrate the general feature for these higher states, which may be valuable for future experimental searches and establishing the singly heavy baryon spectrum.

We investigate quantum chromodynamics with two colors at nonvanishing density using Dyson-Schwinger equations. Lattice methods do not have a complex action problem in this theory. Thus, we can benchmark our results and the effect of truncations directly by comparing with the corresponding lattice results. We do so for the gluon propagator, the chiral condensate, and the quark number density and test variations of the employed truncation to improve the agreement. Finally, we compare the effect of a truncation on the chiral and confinement/deconfinement transitions in the phase diagrams of QCD and QCD with the gauge groups $SU(2)$ and $G_2$.

The QCD baryon number density can formally be expanded into a Laurent series in fugacity, which is a relativistic generalization of Mayer’s cluster expansion. We determine properties of the cluster expansion in a model with a phase transition and a critical point at finite baryon density, in which the Fourier coefficients of the expansion can be determined explicitly and to arbitrary order. The asymptotic behavior of Fourier coefficients changes qualitatively as one traverses the critical temperature and it is connected to the branch points of a thermodynamic potential associated with the phase transition. The results are discussed in the context of lattice QCD simulations at imaginary chemical potential. We argue that the location of a branch point closest to the imaginary chemical potential axis can be extracted through an analysis of an exponential suppression of Fourier coefficients. This is illustrated using the four leading coefficients both in a toy model as well as by using recent lattice QCD data.

The form factors parametrizing the weak $D$ and $D_s$ transitions to light pseudoscalar and vector mesons are calculated in the framework of the relativistic quark model based on the quasipotential approach. The special attention is paid to the systematic account of the relativistic effects including transformation of the meson wave function from the rest to moving reference frame and contributions of the intermediate negative-energy states. The form factors are expressed through the overlap integrals of the meson wave functions, which are taken from previous studies of meson spectroscopy. They are calculated in the whole range of the transferred momentum $q^2$. Convenient parametrization of the form factors which accurately reproduces numerical results is given. The obtained values of the form factors and their ratios at $q^2=0$ agree well with the ones extracted form the experimental data. On the basis of these form factors and helicity formalism, differential and total semileptonic decay rates of $D$ and $D_s$ mesons as well as different asymmetries and polarization parameters are calculated. The detailed comparison of the obtained results with other theoretical calculations and experimental data is given.

Using the initial-state radiation method, the $e^{+}{e}^{-}\to K_S{K}_L$ cross section from 1.98 to 2.54 GeV is measured in a data sample of $469{\mathrm{fb}}^{-1}$ collected with the BABAR detector. The results are used in conjunction with previous BABAR results for the $e^{+}{e}^{-}\to K^{+}{K}^{-}$, $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$, $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\eta$, and $e^{+}{e}^{-}\to \omega \pi \pi$ cross sections to investigate the nature of the resonance structure recently observed by the BESIII experiment in the $e^{+}{e}^{-}\to K^{+}{K}^{-}$ cross section.

Precise calorimetric reconstruction of 5–50 MeV electrons in liquid argon time projection chambers (LArTPCs) will enable the study of astrophysical neutrinos in DUNE and could enhance the physics reach of oscillation analyses. Liquid argon scintillation light has the potential to improve energy reconstruction for low-energy electrons over charge-based measurements alone. Here we demonstrate light-augmented calorimetry for low-energy electrons in a single-phase LArTPC using a sample of Michel electrons from decays of stopping cosmic muons in the LArIAT experiment at Fermilab. Michel electron energy spectra are reconstructed using both a traditional charge-based approach as well as a more holistic approach that incorporates both charge and light. A maximum-likelihood fitter, using LArIAT’s well-tuned simulation, is developed for combining these quantities to achieve optimal energy resolution. A sample of isolated electrons is simulated to better determine the energy resolution expected for astrophysical electron-neutrino charged-current interaction final states. In LArIAT, which has very low wire noise and an average light yield of $18\mathrm{pe}/\mathrm{MeV}$, an energy resolution of $\sigma /E\simeq 9.3\%/\sqrt{E}\oplus 1.3\%$ is achieved. Samples are then generated with varying wire noise levels and light yields to gauge the impact of light-augmented calorimetry in larger LArTPCs. At a charge-readout signal-to-noise of $\mathrm{S}/\mathrm{N}\simeq 30$, for example, the energy resolution for electrons below 40 MeV is improved by $\approx 10\%$, $\approx 20\%$, and $\approx 40\%$ over charge-only calorimetry for average light yields of $10\mathrm{pe}/\mathrm{MeV}$, $20\mathrm{pe}/\mathrm{MeV}$, and $100\mathrm{pe}/\mathrm{MeV}$, respectively.

A passing gravitational wave causes a deflection in the apparent astrometric positions of distant stars. The effect of the speed of the gravitational wave on this astrometric shift is discussed. A stochastic background of gravitational waves would result in a pattern of astrometric deflections which are correlated on large angular scales. These correlations are quantified and investigated for backgrounds of gravitational waves with sub- and superluminal group velocities. The statistical properties of the correlations are depicted in two equivalent and related ways: as correlation curves and as angular power spectra. Sub-(super-)luminal gravitational wave backgrounds have the effect of enhancing (suppressing) the power in low-order angular modes. Analytical representations of the redshift-redshift and redshift-astrometry correlations are also derived. The potential for using this effect for constraining the speed of gravity is discussed.

Peculiar-velocity surveys of the low-redshift universe have significant leverage to constrain the growth rate of cosmic structure and test gravity. Wide-field imaging surveys combined with multiobject spectrographs [e.g., ZTF2, Large Synoptic Survey Telescope (LSST), DESI, and 4MOST] can use type Ia supernovae as informative tracers of the velocity field, reaching few percent constraints on the growth rate $f{\sigma }_8$ at $z\lesssim 0.2$ where density tracers cannot do better than $\sim 10\%$. Combining the high-redshift DESI survey mapping redshift space distortions with a low-redshift supernova peculiar velocity survey using LSST and DESI can determine the gravitational growth index to $\sigma (\gamma )\approx 0.02$, testing general relativity. We study the characteristics needed for the peculiar velocity survey, and how its complementarity with clustering surveys improves when going from a $\mathrm{\Lambda }\mathrm{CDM}$ model assumption to a $w_0–w_a$ cosmology.