In this work we investigate the $\mathrm{\Upsilon }(10753)\to \mathrm{\Upsilon }(1{{}^{3}D}_J)\eta$ ($J=1$, 2, 3) processes, where the $\mathrm{\Upsilon }(10753)$ is assigned as a conventional bottomonium under the $4S–3D$ mixing scheme. Our result shows that the concerned processes have considerable branching ratios, i.e., branching ratios $\mathcal{B}[\mathrm{\Upsilon }(10753)\to \mathrm{\Upsilon }(1{{}^{3}D}_1)\eta ]$ and $\mathcal{B}[\mathrm{\Upsilon }(10753)\to \mathrm{\Upsilon }(1{{}^{3}D}_2)\eta ]$ can reach up to the order of magnitude of ${10}^{-4}–{10}^{-3}$, while $\mathcal{B}[\mathrm{\Upsilon }(10753)\to \mathrm{\Upsilon }(1{{}^{3}D}_3)\eta ]$ is around ${10}^{-6}–{10}^{-5}$. With the running of Belle II, it is a good opportunity for finding out the concerned hidden-bottom hadronic decays.

We investigate the axial-vector transition form factors of the baryon octet to the baryon decuplet within the framework of the chiral quark-soliton model, with the effects of flavor SU(3) symmetry breaking included. We consider the rotational $1/N_c$ corrections and regard the strange current quark mass as a perturbation. We compare the present results for the $\mathrm{\Delta }\to N$ axial-vector transition with those from other models and lattice QCD. We also compute all possible axial-vector transitions from the baryon decuplet to the octet with the strangeness changed, i.e., $|\mathrm{\Delta }S|=1$. We obtain the value of the essential form factor $C_5^A$ for the $\mathrm{\Delta }\to N$ axial-vector transition at the zero momentum transfer ($Q^2=0$). Furthermore, the present results are in good agreement with those fitted with the T2K data. We extract the value of the axial-vector mass $M_A$ compared to the data.

This paper reports results from a search for single and multinucleon disappearance from the ${}^{16}\mathrm{O}$ nucleus in water within the $\mathrm{SNO}+$ detector using all of the available data. These so-called “invisible” decays do not directly deposit energy within the detector but are instead detected through their subsequent nuclear deexcitation and gamma-ray emission. New limits are given for the partial lifetimes: $\tau (n\to \mathrm{inv})>9.0\times {10}^{29}\mathrm{years}$, $\tau (p\to \mathrm{inv})>9.6\times {10}^{29}\mathrm{years}$, $\tau (nn\to \mathrm{inv})>1.5\times {10}^{28}\mathrm{years}$, $\tau (np\to \mathrm{inv})>6.0\times {10}^{28}\mathrm{years}$, and $\tau (pp\to \mathrm{inv})>1.1\times {10}^{29}\mathrm{years}$ at 90% Bayesian credibility level (with a prior uniform in rate). All but the ($nn\to \mathrm{inv}$) results improve on existing limits by a factor of about 3.

We embed the geometries of the generalized $\lambda$ deformations into the framework of the double field theory.

We extend and clarify the large-charge expansion of the conformal dimension ${\mathrm{\Delta }}_Q$ of the lowest operator of charge $Q$ in nonrelativistic conformal field theories using the state-operator correspondence. The latter requires coupling the theory to an external harmonic trap that confines the particles to a spherical cloud, at the edge of which the effective theory breaks down and leads to divergences. Only recently has this issue been overcome by constructing appropriate counterterms at the edge of the cloud [S. Hellerman and I. Swanson, arXiv:2010.07967]. In this paper, we extend these results by systematically analyzing the degree of divergence of operators in the effective action and show that there always exist appropriate edge counterterms that make the final contributions to ${\mathrm{\Delta }}_Q$ finite. On the other side of the correspondence, this also provides new corrections to the Thomas-Fermi approximation of the unitary Fermi gas, and we comment on their relevance for ultracold atom physics.

The inclusion of the Weyl squared term in the gravitational action is one of the most simple, yet nontrivial modifications to general relativity at high energies. Nevertheless the study of the spherically symmetric vacuum solutions of this theory has received much attention only in recent times. A new type of asymptotically flat wormhole which does not match symmetrically at a finite radius with another sheet of the spacetime is presented. The outer spacetime is characterized by a Newtonian potential with a Yukawa correction, and has gravitational properties that can be arbitrarily close to the ones of a Schwarzschild black hole. The internal spacetime instead possesses a singularity at $r=\infty$ with the topology of a 2-dimensional sphere. The expansion scalar of geodesics reaching this singularity diverges in a finite amount of proper time, with a striking resemblance with the future singularity of the big rip cosmological scenario. In terms of the external Yukawa hair and mass $M$, these new wormholes fill a large region of the two-dimensional parameter space of physical solutions with $M>0$. On the contrary black holes, both of Schwarzschild and non-Schwarzschild nature, are confined on a line. We argue that this type of wormholes are ideal black hole mimickers.

Neutron stars can be destroyed by black holes at their center accreting material and eventually by swallowing the entire star. Here we note that the accretion model adopted in the literature, based on Bondi accretion or variations thereof, is inadequate for small black holes—black holes whose Schwarzschild radius is comparable to, or smaller than, the neutron’s de Broglie wavelength. In this case, quantum mechanical aspects of the accretion process cannot be neglected, and give rise to a completely different accretion rate. We show that for the case of black holes seeded by the collapse of bosonic dark matter, this is the case for electroweak-scale dark matter particles. In the case of fermionic dark matter, typically the black holes that would form at the center of a neutron star are more massive, unless the dark matter particle mass is very large, larger than about ${10}^{10}\mathrm{GeV}$. We calculate the lifetime of neutron stars harboring a “small” black hole, and find that black holes lighter than $\sim {10}^{11}\mathrm{kg}$ quickly evaporate, leaving no trace. More massive black holes destroy neutron stars via quantum accretion on timescales much shorter than the age of observed neutron stars. We find that the range where seed black holes inside neutron stars are massive enough that they do not quickly evaporate away, but not so massive that a fluid accretion picture is warranted is limited to between $\sim {10}^{11}$ and ${10}^{12}\mathrm{kg}$, but our results are key to accurately determine the actual critical black hole mass corresponding to the onset of neutron star destruction.

We show that the backreaction of left-handed neutrinos out of equilibrium on the matter sector induces an electric current proportional to a magnetic field even without a chiral imbalance for electrons in core-collapse supernovae. We derive the transport coefficient of this effect based on the recently formulated chiral radiation transport theory for neutrinos. This chiral electric current generates a strong magnetic field via the so-called chiral plasma instability, which could provide a new mechanism for the strong and stable magnetic field of magnetars. We also numerically study the physical origin of the inverse cascade of the magnetic energy in the magnetohydrodynamics including this current. Our results indicate that incorporating the chiral effects of neutrinos would drastically modify the hydrodynamic evolutions of supernovae, which may also be relevant to the explosion dynamics.

We investigate the gravitational waves (GWs) at low frequencies produced by neutrinos that are emitted anisotropically from the protoneutron star (PNS) during its cooling phase that lasts for about a minute. We are particularly interested in the deci-Hz range, in which some satellite-borne detectors are expected to have good sensitivities. We first give a formulation based on the spherical-harmonic expansion of the neutrino luminosity to obtain the gravitational waveform as well as the characteristic strain. In the absence of multidimensional simulations of PNS cooling, from which we can extract reliable data on the neutrino luminosities as a function of a solid angle, we construct them by hand. In the first model, the time evolution is approximated by piecewise exponential functions. In the second model we employ the time profile obtained in a 1D cooling simulation for all harmonic components for simplicity. In both cases, we consider not only axisymmetric components but also nonaxisymmetric ones. In the third model, we consider axisymmetric neutrino emissions, the axis of which is misaligned with the rotation axis and, as a result, rotates with the PNS. We find from the first model that the decay times in piecewise exponential function at late phases can be inferred from the positions of bumps and dips in the characteristic strain of the GW in the case of a slow cooling, whereas they may be obtained by identifying the positions of slope change in the case of rapid cooling, which may be induced by convection in PNS. We confirm the former result also in the second model. The results of the third model show that the gravitational waves emitted by the neutrinos contain circularly-polarized components in contrast to the first two models, in which only linear polarizations occur, and give oscillatory features in the waveform with the frequencies of integral multiples of the rotation frequency, which are also clearly reflected in the characteristic strain. Finally, we compare the GW signals thus obtained with the sensitivity curves of some planned GW detectors that are expected to be sensitive to GWs in the deci-Hz range. If these admittedly crude models are any guide, these detectors, DECIGO in particular, will have a fair chance of detecting the GW signals as we consider them in this paper if they are emitted from within our Galaxy.

Extreme mass ratio inspirals (EMRIs) are among the most interesting gravitational wave (GW) sources for space-borne GW detectors. However, successful GW data analysis remains challenging due to many issues, ranging from the difficulty of modeling accurate waveforms, to the impractically large template bank required by the traditional matched filtering search method. In this work, we introduce a proof-of-principle approach for EMRI detection based on convolutional neural networks (CNNs). We demonstrate the performance with simulated EMRI signals buried in Gaussian noise. We show that over a wide range of physical parameters, the network is effective for EMRI systems with a signal-to-noise ratio larger than 50, and the performance is most strongly related to the signal-to-noise ratio. The method also shows good generalization ability toward different waveform models. Our study reveals the potential applicability of machine learning technology like CNNs toward more realistic EMRI data analysis.

Heavy neutral leptons (HNLs) are an attractive minimal extension of the Standard Model, as is a singlet scalar $s$ mixing with the Higgs boson. If both are present, it is natural for HNLs to interact with $s$. For a light singlet, the decay $N\to s\nu$ can dominate over weak HNL decays. We reinterpret existing constraints on HNL mixing from the DELPHI, CHARM, and Belle experiments for 0.5–100 GeV mass HNLs, taking into account the new decay channel. Although the constraints are typically weakened, in some cases they can become stronger, due to observable $s\to {\ell }^{+}{\ell }^{-}$ decays in the detectors. The method presented here could be used to recast constraints from other (older) experiments without resorting to computationally expensive Monte Carlo simulations. In addition, we update and correct some errors in the analysis of the original constraints, in the absence of the singlet.

Several dark matter models allow for the intriguing possibility of exotic compact object formation. These objects might have unique characteristics that set them apart from their baryonic counterparts. Furthermore, gravitational wave observations of their mergers may provide the only direct window on a potentially entirely hidden sector. Here, we discuss dark white dwarfs, starting with an overview of the microphysical model and analytic scaling relations of macroscopic properties derived from the nonrelativistic limit. We use the full relativistic formalism to confirm these scaling relations and demonstrate that dark white dwarfs, if they exist, would have masses and tidal deformabilities that are very different from those of baryonic compact objects. Further, and most importantly, we demonstrate that dark white dwarf mergers would be detectable by current or planned gravitational observatories across several orders of magnitude in the particle-mass parameter space. Lastly, we find universal relations analogous to the compactness-Love and binary Love relations in neutron star literature. Using these results, we show that gravitational wave observations would constrain the properties of the dark matter particles constituting these objects.

We propose a mechanism that forms primordial black holes (PBHs) via a first-order electroweak phase transition (FOEWPT). The FOEWPT is realized by extending the Standard Model with a real singlet scalar, while the PBH formation is achieved by the collapse of nontopological solitons called Fermi-balls. Such solitons form via trapping fermions in the false vacuum during the FOEWPT, and they eventually collapse into PBHs due to the internal Yukawa attractive force. We demonstrate that a scenario with PBH dark matter candidate can exist, and the typical experimental signals include FOEWPT gravitational waves and the multilepton/jet or displaced vertex final states at the LHC.

We analyze the $\gamma N\to \pi N$ process in the negative parity channel with Hamiltonian effective field theory, which is successful in studying the nucleon resonances associated with the meson-nucleon scattering and lattice QCD simulations. We provide the scattering amplitude of pion photoproduction and extract the electric dipole amplitudes $E_{0+}$. The bare $N^{*}(1535)$ is important for improving the consistency between our results and the experimental data.

We report the results of a new global QCD analysis, which includes deep-inelastic $e/\mu$ scattering data off proton and deuterium, as well as Drell-Yan lepton pair production in proton-proton and proton-deuterium collisions and $W^{\pm }/Z$ boson production data from $pp$ and $p\overline{p}$ collisions at the LHC and Tevatron. Nuclear effects in the deuteron are treated in terms of a nuclear convolution approach with bound off-shell nucleons within a weak binding approximation. The off-shell correction is controlled by a universal function of the Bjorken variable $x$, describing the modification of parton distributions in bound nucleons, which is determined in our analysis along with the parton distribution functions of the proton. A number of systematic studies are performed to estimate the uncertainties arising from the use of various deuterium datasets, from the modeling of higher twist contributions to the structure functions, from the treatment of target mass corrections, as well as from the nuclear corrections in the deuteron. We obtain predictions for the ratios $F_2^n/F_2^p$, and $d/u$, focusing on the region of large $x$. We also compare our results with the ones obtained by other QCD analyses, as well as with the recent data from the MARATHON experiment.

The sensitivity to new physics of a low threshold scintillating argon bubble chamber measuring coherent elastic neutrino-nucleus scattering in reactors is reported. Namely, light scalar mediators, sterile neutrino oscillations, unitarity violation, and nonstandard interactions are studied. The results indicate that this detector could be able to set stronger constraints than current limits set by the recent COHERENT measurements. Considering the best scenario, a 100 kg detector located 30 m from a $2000{\mathrm{MW}}_{th}$ reactor, a sterile neutrino search would cover most of the space parameter allowed from the reactor antineutrino anomaly fit. Unitarity violation studies could set constraints on ${\alpha }_{11}$, more stringent than the current oscillation experiments fit. A low threshold argon detector with very low backgrounds has the potential to explore new physics in different scenarios and set competitive constraints.

Based on the potential nonrelativistic QCD formalism, we compute the nonrelativistic QCD long-distance matrix elements (LDMEs) for inclusive production of $S$-wave heavy quarkonia. This greatly reduces the number of nonperturbative unknowns and brings in a substantial enhancement in the predictive power of the nonrelativistic QCD factorization formalism. We obtain improved determinations of the LDMEs and find cross sections and polarizations of $J/\psi$, $\psi (2S)$, and excited $\mathrm{\Upsilon }$ states that agree well with LHC data. Our results may have important implications in pinning down the heavy quarkonium production mechanism.

We reconsider the Lee-Wick (LW) models and compare their properties to the properties of the models that contain purely virtual particles. We argue against the LW premise that unstable particles can be removed from the sets of incoming and outgoing states in scattering processes. The removal leads to a non-Hermitian classical limit, besides clashing with the observation of the muon. If, on the other hand, all the states are included, the LW models have a Hamiltonian unbounded from below or negative norms. Purely virtual particles, on the contrary, lead to a Hermitian classical limit and are absent from the sets of incoming and outgoing states without implications on the observation of long-lived unstable particles. We give a vademecum to summarize the properties of most options to treat abnormal particles. We study a method to remove the LW ghosts only partially, by saving the physical particles they contain. Specifically, we replace a LW ghost with a certain superposition of a purely virtual particle and an ordinary particle, and drop only the former from the sets of the external states. The trick can be used to make the Pauli-Villars fields consistent and observable, without sending their masses to infinity, or to build a finite QED, by tweaking the original Lee-Wick construction. However, it has issues with general covariance, so it cannot be applied as is to quantum gravity, where a manifestly covariant decomposition requires the introduction of a massive spin-2 multiplet.

The $C$-metric is a boost-symmetric spacetime solution to the vacuum Einstein field equations which describes black holes that are uniformly accelerated under the tension of a cosmic string. Only recently the thermodynamics of accelerating black holes and their modal stability against neutral scalar perturbations were concisely established. The generalization of accelerating black holes to incorporate an electric charge, namely the charged $C$-metric, possess three distinct families of quasinormal mode frequencies; the complex photon surface quasinormal modes associated with unstable null particles at the equatorial plane of the photon surface, the purely imaginary acceleration modes whose existence solely depends on the acceleration of spacetime and the purely imaginary near-extremal modes which dominate the dynamics of the ringdown at late times when the event and Cauchy horizon approach each other. We extend the quasinormal mode analysis to charged scalar fluctuations and find that the photon surface modes are continuously deformed with respect to their neutral counterpart as the scalar charge is increased. We further find that the acceleration and near-extremal families acquire an oscillation frequency when the scalar charge is introduced. Finally, we study the superradiant amplification of charged scalar monochromatic waves impinging charged accelerating black holes. We find that even though the frequency range of superradiant amplification is lessened due to the acceleration, the amplification factors are considerably elevated with respect to those transpiring in Reissner-Nordström black holes and are maximized when the scalar charge is significantly large.

Estimating the source parameters of gravitational waves from compact binary coalescence (CBC) is a key analysis task in gravitational-wave astronomy. To deal with the increasing detection rate of CBC signals, optimizing the parameter estimation analysis is crucial. The analysis typically employs a stochastic sampling technique such as Markov Chain Monte Carlo (MCMC), where the source parameter space is explored and regions of high-Bayesian posterior probability density are found. One of the bottlenecks slowing down the analysis is the nontrivial correlation between masses and spins of colliding objects, which makes the exploration of mass-spin space extremely inefficient. We introduce a new set of mass-spin sampling parameters which makes the posterior distribution simpler in the new parameter space, regardless of the true values of the parameters. The new parameter combinations are obtained as the principal components of the Fisher matrix for the restricted 1.5 post-Newtonian waveform. Our reparametrization improves the efficiency of MCMC by a factor of $\sim 10$ for a binary neutron star with a narrow-spin prior ($|\overrightarrow{\chi }|<0.05$) and $\sim 100$ for a binary neutron star with a broad-spin prior ($|\overrightarrow{\chi }|<0.99$), under the assumption that the binary has spins aligned with its orbital angular momentum.