We investigate a scale-invariant $B-L$ scenario where the Standard Model (SM) is supplemented with a dark scalar $\varphi$ which has gauge and Yukawa interactions, with the couplings $g_{BL}$ and $y$, respectively, leading to radiative plateau inflation at scale $\varphi =M$ in the ultraviolet (UV), while dynamically generating the electroweak and seesaw scales á la Coleman-Weinberg in the infrared (IR). This is particularly achieved by implementing threshold corrections at an energy scale ${\mu }_T$ arising due to the presence of vectorlike fermions. We show that implementing the inflationary observables makes the couplings solely dependent on the plateau scale $M$, leaving us with only two independent parameters $M$ and ${\mu }_T$. Within the theoretically consistent parameter space defined by $m_{Z_{BL}}>850\mathrm{GeV}$, from the assumption of independent evolution of the dark sector couplings from the SM couplings and $M<5.67M_P$ required for the realization of inflationary plateaulike behavior of the potential around $\varphi =M$, where $M_P=2.4\times {10}^{18}\mathrm{GeV}$ is the reduced Planck mass, we identify the parameter space that is excluded by the current LHC results from the search for the heavy $Z_{BL}$ boson. For typical benchmark points in the viable parameter regions, we estimate the reheating temperature to be $\mathcal{O}(\mathrm{TeV})$ thus consistent with the standard big bang nucleosynthesis (BBN) constraints. For typical benchmark points ($M=5.67,1,0.1M_P$) we predict the scales of inflation to be ${\mathcal{H}}_{\inf }=2.79\times {10}^{12}\mathrm{GeV}$, $1.53\times {10}^{10}\mathrm{GeV}$, and $1.53\times {10}^7\mathrm{GeV}$, respectively.

We study the high-scale validity of a type-X two Higgs doublet scenario, which provides an explanation of the observed value of muon ($g-2$). This region allows a pseudoscalar physical state, which is well below the observed 125-GeV scalar in mass. A second neutral scalar particle can be both above and below 125 GeV in such a scenario. Admissible regions in the parameter space are obtained by using the most recent data on muon ($g-2$), theoretical constraints such as low-scale perturbativity and vacuum stability, and also all experimental constraints, including the available LHC results. Among other things, both the aforesaid orders of $CP$-even neutral scalar masses are included in our benchmark studies. Two-loop renormalization group equations are used to predict the values of various couplings at high scales, and the regions in the space spanned by low-scale parameters, which retain perturbative unitarity as well as vacuum stability up to various scales are identified. We thus conclude that such a scenario, while successfully explaining the observed muon ($g-2$), can be valid up to energy scales ranging from ${10}^4\mathrm{GeV}$ to the Planck scale, thus opening up directions of thought on its ultraviolet completion.

The quark model symmetry can be adopted to establish relations between the low-energy constants (LECs) in the baryon chiral perturbation theory ($\chi PT$) if one assumes that a baryon-baryon-meson coupling is described equivalently by a quark-quark-meson coupling at the quark level. Through the correspondence between the $SU(2)$ description and the $SU(3)$ description for the same coupling vertex at the quark level, we find some relations between the LECs in $SU(2{)}_{\chi PT}$ and $SU(3{)}_{\chi PT}$ up to the third chiral order. The $SU(3{)}_{\chi PT}$ LEC relations at the same order are also obtained. The numerical analysis roughly supports these relations. In the situation that the available experimental data are not enough, one may employ such constraints to reduce the number of LECs.

We compare a nonfactorizable charming-loop correction to an exclusive FCNC $B$ decay given in terms of the three-particle Bethe-Salpeter amplitude (3BS) of the $B$ meson, $⟨0|\overline{q}(x)G_{\mu \nu }(z)b(0)|B(p)⟩$, with the corresponding correction to the $B$-meson semileptonic form factor. In spite of certain similarities, these two corrections are shown to have substantial differences: the form-factor correction is dominated by the collinear light-cone configuration of 3BS ($z_{\mu }=u{x}_{\mu }$, $0<u<1$, $x^2=0$); in contrast, the FCNC amplitude is dominated by a different configuration with noncollinear arguments [$x^2=0$, $z^2=0$, but $(x-z{)}^2\ne 0$ (i.e., $z_{\mu }\ne u{x}_{\mu }$)].

We calculate the relativistic six-meson scattering amplitude at low energy within the framework of QCD-like theories with $n$ degenerate quark flavors at next-to-leading order in the chiral counting. We discuss the cases of complex, real and pseudoreal representations, i.e. with global symmetry and breaking patterns $\mathrm{SU}(n)\times \mathrm{SU}(n)/\mathrm{SU}(n)$ (extending the QCD case), $\mathrm{SU}(2n)/\mathrm{SO}(2n)$, and $\mathrm{SU}(2n)/\mathrm{Sp}(2n)$. In case of the one-particle-irreducible part, we obtain analytical expressions in terms of ten six-meson subamplitudes based on the flavor and group structures. We extend on our previous results obtained within the framework of the $\mathrm{O}(N+1)/\mathrm{O}(N)$ nonlinear sigma model, with $N$ being the number of meson flavors. This work allows for studying a number of properties of six-particle amplitudes at one-loop level.

Inspired by the observation of the $P_{\psi s}^{\mathrm{\Lambda }}(4459)$ and $P_{\psi s}^{\mathrm{\Lambda }}(4338)$, we systematically investigate the magnetic moments, the transition magnetic moments, and the radiative decay behaviors of the $S$-wave isoscalar ${\mathrm{\Xi }}_c^{(\prime )}{\overline{D}}^{(*)}$ molecular pentaquark states in this work. Our quantitative investigation shows that their electromagnetic properties can provide important hints to decode the inner structure of these discussed isoscalar ${\mathrm{\Xi }}_c^{(\prime )}{\overline{D}}^{*}$ molecular pentaquarks. As a potential research issue, we suggest future experiments to focus on the electromagnetic properties of these isoscalar ${\mathrm{\Xi }}_c^{(\prime )}{\overline{D}}^{(*)}$ molecular pentaquarks, which are a typical hidden-charm molecular pentaquark system with single strangeness.

The electroweak symmetry-breaking sector is one of the most promising and uncharted parts of the Standard Model (SM); but it seems likely that new electroweak physics may be out of reach of the present accelerator effort and the hope is to observe small deviations from the SM. Given that, effective field theory (EFT) becomes the logic method to use, and Standard Model effective field theory (SMEFT) has become the standard. However, the most general theory with the known particle content is Higgs effective field theory (HEFT), and whether SMEFT suffices should be investigated in future experimental efforts. Building on investigations by other groups that established geometric criteria to distinguish SMEFT from HEFT (useful for theorists examining specific beyond-SM completions), we seek more phenomenological understanding and present an analogous discussion aimed at a broader audience. We discuss various aspects of (multi)Higgs boson production from longitudinal electroweak gauge bosons $W_L{W}_L\to n\times h$ in the TeV region as the necessary information to characterize the flare function, $\mathcal{F}(h)$, that determines whether SMEFT or HEFT is needed. We also present tree-level amplitudes including contact and exchange channels, as well as a short discussion on accessing $\mathcal{F}$ from the statistical limit of many bosons. We also discuss the status of the coefficients of the series expansion of $\mathcal{F}(h)$, its validity, whether its complex-$h$ extension can be used to predict or not a tell-tale zero, and how they relate to the dimension-six and -eight SMEFT operators in the electroweak sector. We derive a set of new correlations among beyond the standard model corrections to the HEFT coefficients that help decide, from experimental data, whether we have a viable SMEFT. This analysis can be useful for machines beyond the LHC that could address the challenging final state with several Higgs bosons.

We study the dynamical spontaneous scalarization of charged black hole in asymptotically anti–de Sitter spacetimes in Einstein-Maxwell-scalar models. Including various nonminimal couplings between the scalar field and Maxwell field, an initial scalar-free black hole suffers tachyonic instability, and both the scalar field and the black hole irreducible mass grow exponentially at early times and saturate exponentially at late times. For fractional coupling, we find that, though there is negative energy distribution near the horizon, the black hole horizon area never decreases during the evolution. But when the parameters are large, the evolution end points of linearly unstable bald black holes will be spacetimes with a naked singularity such that the cosmic censorship is violated. The effects of the black hole charge, cosmological constant, and coupling strength on the dynamical scalarization process are studied in detail. We find that a large enough cosmological constant can prevent spontaneous scalarization.

Dark compact objects (“clumps”) transiting the Solar System exert accelerations on the test masses (TM) in a gravitational-wave (GW) detector. We reexamine the detectability of these clump transits in a variety of current and future GW detectors, operating over a broad range of frequencies. TM accelerations induced by clump transits through the inner Solar System have frequency content around $f\sim \mu \mathrm{Hz}$. Some of us [Fedderke et al., Phys. Rev. D 105, 103018 (2022)] recently proposed a GW detection concept with $\mu \mathrm{Hz}$ sensitivity, based on asteroid-to-asteroid ranging. From the detailed sensitivity projection for this concept, we find both analytically and in simulation that purely gravitational clump–matter interactions would yield one detectable transit every $\sim 20\mathrm{yrs}$, if clumps with mass $m_{\mathrm{cl}}\sim {10}^{14}\mathrm{kg}$ saturate the dark-matter (DM) density. Other (proposed) GW detectors using local TMs and operating in higher frequency bands are sensitive to smaller clump masses and have smaller rates of discoverable signals. We also consider the case of clumps endowed with an additional attractive long-range clump–matter fifth force significantly stronger than gravity (but evading known fifth-force constraints). For the $\mu \mathrm{Hz}$ detector concept, we use simulations to show that, for example, a clump–matter fifth-force $\sim {10}^3$ times stronger than gravity with a range of $\sim \mathrm{AU}$ would boost the rate of detectable transits to a few per year for clumps in the mass range ${10}^{11}\mathrm{kg}\lesssim m_{\mathrm{cl}}\lesssim {10}^{14}\mathrm{kg}$, even if they are a $\sim 1\%$ subcomponent of the DM. The ability of $\mu \mathrm{Hz}$ GW detectors to probe asteroid-mass-scale dark objects that may otherwise be undetectable bolsters the science case for their development.

Our current understanding of the core-collapse supernova explosion mechanism is incomplete, with multiple viable models for how the initial shock wave might be energized enough to lead to a successful explosion. Detection of a gravitational-wave signal emitted in the initial few seconds after stellar core-collapse would provide unique and crucial insight into this process. With the Advanced LIGO and Advanced Virgo detectors expected to approach their design sensitivities soon, we could potentially detect this signal from a supernova within our galaxy. In anticipation of such a scenario, we study how well the BayesWave algorithm can recover the gravitational-wave signal from core-collapse supernova models in simulated advanced detector noise, and optimize its ability to accurately reconstruct the signal waveforms. We find that BayesWave can confidently reconstruct the signal from a range of supernova explosion models in Advanced LIGO-Virgo for network signal-to-noise ratios $\gtrsim 30$, reaching maximum reconstruction accuracies of $\sim 90\%$ at $\mathrm{SNR}\sim 100$. For low SNR signals that are not confidently recovered, our optimization efforts result in gains in reconstruction accuracy of up to 20%–40%, with typical gains of $\sim 10\%$.

Locally constant crossed field approximation (LCFA) is a powerful tool for theoretical and numerical studies of various strong field quantum electrodynamical effects. We explore this approximation in detail for photon emission by a spinless particle in a strong time-dependent electric field. This kind of electromagnetic fields is of particular interest, because, in contrast to the comprehensively studied case of a plane wave, they are not crossed. We develop an approach for calculating photon emission probability in a generic time-dependent electric field, establish the range of applicability of LCFA, and calculate the corrections to it.

With theoretical constraints such as perturbative unitarity and vacuum stability conditions and updated experimental data of Higgs measurements and direct searches for exotic scalars at the LHC, we perform an updated scan of the allowed parameter space of the Georgi-Machacek (GM) model. With the refined global fit, we examine the allowed parameter space for inducing strong first-order electroweak phase transitions and find only the one-step phase transition is phenomenologically viable. Based upon the result, we study the associated gravitational wave signals and find most of which can be detected by several proposed experiments. We also make predictions on processes that may serve as promising probes to the GM model in the near future at the LHC, including the di-Higgs productions and several exotic scalar production channels.

Reconstructing spectral functions from Euclidean Green’s functions is an important inverse problem in many-body physics. However, the inversion is proved to be ill-posed in the realistic systems with noisy Green’s functions. In this paper we propose an automatic differentiation (AD) framework as a generic tool for the spectral reconstruction from propagator observable. Exploiting the neural networks’ regularization as a nonlocal smoothness regulator of the spectral function, we represent spectral functions by neural networks and use the propagator’s reconstruction error to optimize the network parameters unsupervisedly. In the training process, except for the positive-definite form for the spectral function, there are no other explicit physical priors embedded into the neural networks. The reconstruction performance is assessed through relative entropy and mean square error for two different network representations. Compared to the maximum entropy method, the AD framework achieves better performance in the large-noise situation. It is noted that the freedom of introducing nonlocal regularization is an inherent advantage of the present framework and may lead to substantial improvements in solving inverse problems.

Using the assumption that the independent gauge invariant couplings on the world-volume of the nonperturbative objects in the string theory are independent of the background, we find the four and the six gauge field strength and/or the second fundamental form couplings on the world volume of a ${\mathrm{D}}_p$-brane in the superstring theory at order ${\alpha }^{\prime 2}$ in the normalization that $F$ is dimensionless. We have found them by considering the particular background which has one circle and by imposing the corresponding T-duality constraint on the independent couplings. In particular, we find that there are $12+146$ independent gauge invariant couplings at this order, and the T-duality constraint can fix 150 of them. We show that these couplings are fully consistent with the partial results in the literature. This comparison also fixes the remaining 8 couplings.

The equatorial symmetry of the Kerr black hole is generically broken in models of quantum gravity. Nevertheless, most phenomenological models start from the assumption of equatorial symmetry, and little attention has been given to the observability of this smoking gun signature of physics beyond general relativity. Extreme mass-ratio inspirals (EMRIs), in particular, are known to sensitively probe supermassive black holes near their horizon; yet estimates for constraints on deviations from Kerr in space-based gravitational wave observations (e.g., with LISA) of such systems are currently based on equatorially symmetric models. We use modified “analytic kludge” waveforms to estimate how accurately LISA EMRIs will be able to measure or constrain equatorial symmetry breaking, in the form of the lowest-lying odd-parity multipole moments $S_2$, $M_3$. We find that the dimensionless multipole ratios such as $S_2/M^3$ will typically be detectable with a measurement accuracy of $\mathrm{\Delta }(S_2/M^3)\simeq 1\%$. This would be a precision test of the equatorial symmetry of black holes.

The recent transition from decelerated to accelerated expansion can be seen as a reflection (or “bounce”) in the connection variable, defined by the inverse comoving Hubble length ($b=\dot{a}$, on shell). We study the quantum cosmology of this process. We use a formalism for obtaining relational time variables either through the demotion of the constants of nature to integration constants, or by identifying fluid constants of motion. We extend its previous application to a toy model (radiation and $\mathrm{\Lambda }$) to the realistic setting of a transition from dust matter to $\mathrm{\Lambda }$ domination. In the dust and $\mathrm{\Lambda }$ model two time variables may be defined, conjugate to $\mathrm{\Lambda }$ and to the dust constant of motion, and we work out the monochromatic solutions to the Schrödinger equation representing the Hamiltonian constraint. As for their radiation and $\mathrm{\Lambda }$ counterparts, these solutions exhibit “ringing,” whereby the incident and reflected waves interfere, leading to oscillations in the amplitude. In the semiclassical approximation we find that, close to the bounce, the probability distribution becomes double peaked, one peak following a trajectory close to the classical limit but with a Hubble parameter slightly shifted downwards, the other with a value of $b$ stuck at its minimum $b=b_{\star }$. Still closer to the transition, the distribution is better approximated by an exponential distribution, with a single peak at $b=b_{\star }$, and a (more representative) average $b$ biased towards a value higher than the classical trajectory. Thus, we obtain a distinctive prediction for the average Hubble parameter with redshift: slightly lower than its classical value when $z\approx 0$, but potentially much higher than the classical prediction around $z\sim 0.64$, where the bounce most likely occurred. The implications for the “Hubble tension” have not escaped us.

The Hubble tension seems to be a crisis with $\sim 5\sigma$ discrepancy between the most recent local distance ladder measurement from type Ia supernovae calibrated by Cepheids and the global fitting constraint from the cosmic microwave background data. To narrow down the possible late-time solutions to the Hubble tension, we have used in a recent study [Phys. Rev. D 105, L021301 (2022)] an improved inverse distance ladder method calibrated by the absolute measurements of the Hubble expansion rate at high redshifts from the cosmic chronometer data, and found no appealing evidence for new physics at the late time beyond the $\mathrm{\Lambda }\mathrm{CDM}$ model characterized by a parametrization based on the cosmic age. In this paper, we further investigate the perspective of this improved inverse distance ladder method by including the late-time matter perturbation growth data. Independent of the dataset choices, model parametrizations, and diagnostic quantities ($S_8$ and $S_{12}$), the new physics at the late time beyond the $\mathrm{\Lambda }\mathrm{CDM}$ model is strongly disfavored so that the previous late-time no-go guide for the Hubble tension is further strengthened.

We study an asymmetric dark matter model with self-interacting dark matter consisting of a Dirac fermion $\chi$ coupled to a scalar or vector mediator, such that the reaction $\chi +\chi \to \chi +\chi$ is well described by perturbation theory. We compute the scattering cross section $\sigma$, the transfer cross section ${\sigma }_T$, and the viscosity cross section ${\sigma }_V$ for this reaction. As one part of our study, we give analytic and numerical comparisons of results obtained with the inclusion of both $t$-channel and $u$-channel exchanges and results obtained in an approximation that has often been used in the literature that includes only the $t$-channel contribution. The velocity dependences of these cross sections are studied in detail and shown to be in accord with observational data.