Masses, widths, and branching ratios of hadronic resonances are quantified by their pole positions and residues with respect to transition amplitudes on the Riemann sheets of the complex energy plane. In this study, we discuss the analytic structure in the physical energy region of three-body scattering amplitudes on such manifolds. As an application, we determine the pole position of the $a_1(1260)$ meson from the ALEPH experiment by allowing for $\pi \rho$ coupled channels in $S$ and $D$ waves. We find it to be $\sqrt{s_0}=(1232_{-0-11}^{+15+9}-i266_{-22-27}^{+0+15})\mathrm{MeV}$.

Motivated by the discovery of the doubly charmed state $T_{cc}^{+}$ and with the help of light-cone sum rules, the magnetic moments of possible $T_{cc}^{++}$ states are calculated. While calculating the magnetic moments of these states, these particles are considered in the molecular picture and they have $J^P=1^{+}$ quantum numbers. The magnetic moment results obtained for the $T_{cc}^{++}$ states are large due to the double electric charge. The results obtained in this study can be checked using other theoretical models. The magnetic moments of the hadrons reveal valuable knowledge about the size and the shape of the hadrons. Measurement of the magnetic moment of the $T_{cc}^{++}$ states in future experimental collaborations can be very useful to understanding substructure and identification the quantum numbers of these states.

The observation of the exotic states $X_{0,1}(2900)$ with four open flavors by the LHCb Collaboration has promoted great interest in searching for the open-charm and open-bottom tetraquark states. In this work, we perform a systematic study of the open-heavy tetraquark systems $qq\overline{q}\overline{Q}$ ($q=u$, $d$, $s$ and $Q=c$, $b$) within the improved chromomagnetic interaction model. The mass spectra and color-spin wave functions of $S$-wave open-heavy tetraquark states with quantum numbers $J^P=0^{+}$, $1^{+}$, and $2^{+}$ are calculated. A number of compact tetraquark states are predicted in both open-charm and open-bottom systems. The two-body decay properties of these tetraquark states are phenomenologically analyzed. Our results suggest that the exotic open-charm state $X_0(2900)$ observed by the LHCb Collaboration is likely a compact tetraquark state with quantum number $I{J}^P=00^{+}$ (isospin singlet). For the open-bottom systems, our results also suggest a candidate for the exotic state $X^{\pm }(5568)$ reported by the D0 Collaboration. The other tetraquark states predicted in this work may also be examined in future experiments.

The decay ${\mu }^{-}\to e^{-}{\overline{\nu }}_e{\nu }_{\mu }$ of a muon that is bound to a nucleus poses an unavoidable background for experiments such as Mu2e, COMET, and DeeMe searching for lepton-flavor-violating ${\mu }^{-}\to e^{-}$ conversion and thus requires a precise understanding. We calculate the electron-energy spectra of muon decays in orbit near the electron energy end point for all stable isotopes and estimate uncertainties due to the nuclear charge distribution. Our results enable background studies of mixed or enriched target materials that are necessary for the next generation of ${\mu }^{-}\to e^{-}$ conversion experiments.

In the present work, we investigate the image of a power-Yang-Mills black hole and its luminosity under distinctive accretion models. Meanwhile, a special emphasis is put on the different image characteristics of the distant observer when the related physical quantity of the black hole varies. Concretely, after showing the power Yang-Mills black hole’s relevance with the Event Horizon Telescope data, we unveil the impact of the power parameter $\gamma$ on the photon trajectories, the observed intensity, and consequently on the image formation of such black hole. Furthermore, we establish that for the thin disk accretion model that the shadow, lens ring, and photon ring appear near the black hole following some parameter impact ranges. We also show that due to the extreme demagnetization, the remote observer cannot obtain the observation flux provided by the photon ring. Hence, the intensity of observation is provided by the direct image from accretion, and the lens ring also contributes, but only a small part. In addition, different emission profiles of the accretion will also directly affect the observed specific intensity. Such investigations have been realized within a variety of $\gamma$’s values. Later, the spherical infalling accretion model is considered and discussed within the $\gamma$ variation and by paying attention to the conformally invariant case associated with $\gamma =\frac{3}{4}$. Lastly, one concludes that the black hole presents a larger intensity as the power parameter $\gamma$ increases. In a word, observational appearances of the power Yang-Mills black hole surrounded by various accretions present some nice features that can be used to distinguish black holes from different gravity theories.

Primordial magnetic fields are generated during inflation by considering actions that break the conformal invariance of the electromagnetic field. To break the conformal invariance, the electromagnetic fields are coupled either to the inflaton or to the scalar curvature. Also, a parity violating term is often added to the action in order to enhance the amplitudes of the primordial electromagnetic fields. In this work, we examine the effects of deviations from slow roll inflation on the spectra of nonhelical as well as helical electromagnetic fields. We find that, in the case of the coupling to the scalar curvature, there arise certain challenges in generating electromagnetic fields of the desired shapes and strengths even in slow roll inflation. When the field is coupled to the inflaton, it is possible to construct model-dependent coupling functions that lead to nearly scale invariant magnetic fields in slow roll inflation. However, we show that sharp features in the scalar power spectrum generated due to departures from slow roll inflation inevitably lead to strong features in the power spectra of the electromagnetic fields. Moreover, we find that such effects can also considerably suppress the strengths of the generated electromagnetic fields over the scales of cosmological interest. We illustrate these aspects with the aid of inflationary models that have been considered to produce specific features in the scalar power spectrum. Further, we find that, in such situations, if the strong features in the electromagnetic power spectra are to be undone, the choice of the coupling function requires considerable fine tuning. We discuss wider implications of the results we obtain.

Black holes are considered to be exceptional due to their time evolution and information processing. However, it was proposed recently that these properties are generic for objects, the so-called saturons, that attain the maximal entropy permitted by unitarity. In the present paper, we verify this connection within a renormalizable $SU(N)$ invariant theory. We show that the spectrum of the theory contains a tower of bubbles representing bound states of $SU(N)$ Goldstones. Despite the absence of gravity, a saturated bound state exhibits a striking correspondence with a black hole: Its entropy is given by the Bekenstein-Hawking formula; semiclassically, the bubble evaporates at a thermal rate with a temperature equal to its inverse radius; the information retrieval time is equal to Page’s time. The correspondence goes through a trans-theoretic entity of the Poincaré Goldstone. The black hole–saturon correspondence has important implications for black hole physics, both fundamental and observational.

At sufficiently low temperature, without requiring any numerical data at finite real chemical potential, we can clarify the canonical partition function with a fixed quark number via the imaginary chemical potential region with few Ansätze. The canonical partition function relates to the multiplicity distribution which can be observed in collider experiments and thus we may access important information of the properties of the QCD matter based on the canonical method. In this paper, we estimate the multiplicity entropy, the configuration entropy, and the pointwise information which can be calculable with the canonical partition function to understand the properties of the cold QCD matter at finite density. With a large-$N_{\mathrm{c}}$ limit where $N_{\mathrm{c}}$ is the number of colors, we can simply estimate the tendency of them, and then the relation to the quarkyonic phase is clarified. In addition, we discuss the nontrivial ground-state degeneracy from the viewpoint of the canonical sectors.

We consider a dynamical model for dark energy based on an ultralight mass scalar field with very large-scale inhomogeneities. This model may cause observable impacts on the anisotropic properties of the cosmic microwave background (CMB) intensity and luminosity distance. We formulate the model as the cosmological perturbations of the superhorizon scales, focusing on the local region of our universe. Moreover, we investigated the characteristic properties of the late-time evolution of inhomogeneous dark energy. Our numerical solutions show that the model can mimic the standard $\mathrm{\Lambda }\mathrm{CDM}$ cosmology while including spatially dependent dark energy with flexible ranges of the model parameters. We put a constraint on the amplitude of these inhomogeneities of the dark energy on very large scales with the observations of the CMB anisotropies. We also discuss their influence on the estimation of the luminosity distance.

We propose an algebraic construction of the operator-state correspondence in nonrelativistic conformal field theories by explicitly constructing an automorphism of the Schrödinger algebra relating generators in different frames. It is shown that the construction follows closely that of relativistic conformal field theories.

A joint hierarchical Bayesian analysis of the binary black hole (BBH) mass function, merger rate evolution, and cosmological parameters can be used to extract information on both the cosmological and population parameters. We extend this technique to include the effect of modified gravitational wave (GW) propagation. We discuss the constraints on the parameter ${\mathrm{\Xi }}_0$ that describe this phenomenon [with ${\mathrm{\Xi }}_0=1$ in general relativity (GR)] using the data from the third gravitational wave transient catalog. We find the constraints ${\mathrm{\Xi }}_0=1.2_{-0.7}^{+0.7}$ with a flat prior on ${\mathrm{\Xi }}_0$, and ${\mathrm{\Xi }}_0=1.0_{-0.8}^{+0.4}$ with a prior uniform in $\log {\mathrm{\Xi }}_0$ (68% C.L., maximum posterior and highest-density interval), which only rely on the presence of a feature in the BBH mass distribution around $\sim 30–45M_{\odot }$ and are robust to whether or not the event GW190521 is considered an outlier of the population. We then study in more detail the effects of modified GW propagation on population and cosmological analyses for LIGO/Virgo at design sensitivity. We find that, for a given data-taking period, the relative error $\mathrm{\Delta }{\mathrm{\Xi }}_0/{\mathrm{\Xi }}_0$ has a significant dependence on the fiducial value of ${\mathrm{\Xi }}_0$, since the latter has a strong influence on the detection rate. For five years of data, the accuracy ranges from $\sim 10\%$ on ${\mathrm{\Xi }}_0$ when ${\mathrm{\Xi }}_0=1$ to $\mathrm{\Delta }{\mathrm{\Xi }}_0/{\mathrm{\Xi }}_0\sim 20\%$ for ${\mathrm{\Xi }}_0=1.8$, which represents a large deviation from GR, still consistent with current limits and predicted by viable cosmological models. For the Hubble parameter, we forecast an accuracy of $\mathrm{\Delta }{H}_0/H_0\sim 20\%$ and an accuracy on $H(z)$ of $\sim 7\%$ at a pivot redshift $z_{*}\sim 0.8$; this updates the results found in previous studies, by making use of a population model compatible with current observations, and is about a factor 2 worse, in twice the observing time. We finally show that, if nature is described by a modified gravity theory with a large deviation from the GR value ${\mathrm{\Xi }}_0=1$, such as ${\mathrm{\Xi }}_0=1.8$, analyzing the data assuming GR produces a significant bias in the inferred values of the mass scales, Hubble constant, and particularly the BBH merger rate.

Ultralight bosons, as important candidates of dark matter, can condense around spinning black holes (BHs) to form long-lived “boson clouds” due to superradiant instabilities. The boson-BH system can be observed through gravitational wave detection and may become a new window to find traces of ultralight bosons. In this paper, we explore the effects on the superradiant instabilities of BHs from the near-horizon microstructure. By introducing the reflection parameter near a BH horizon, we derive analytical results on the corrections to both energy levels of the bosonic cloud and its characteristic frequencies of superradiant instabilities. Our results imply that the evolution of a boson-BH system and the gravitational waves it emits would be influenced by the near-horizon physics of a BH.

We propose that a quantum black hole can produce a new kind of late-time gravitational echoes, facilitated by a near-horizon process analogous to Andreev reflection in condensed matter systems. In comparison to the traditional echo scenarios where the near-horizon region is treated as an ordinary reflector, we argue that, consequent to near-horizon gravitational scattering, this region is better described by an Andreev reflector. Such interactions lead to a novel contribution to gravitational echoes with a characteristic phase difference, an effect which is analogous to how Andreev reflections lead to propagating particlelike and holelike components with a relative phase in certain condensed matter scenarios. Moreover, this novel contribution to the echo signal encodes information about the “near-horizon quantum state,” hence offering a possible new window to probe the quantum nature of black holes.

We implement adaptive mesh refinement simulations of global topological strings using the public numerical relativity code, GRChombo. We perform a quantitative investigation of the dynamics of single sinusoidally displaced string configurations, studying a wide range of string energy densities $\mu \propto \ln \lambda$, defined by the string width parameter $\lambda$ over 2 orders of magnitude. We investigate the resulting massless (Goldstone boson or axion) radiation signals, using quantitative diagnostic tools to determine the eigenmode decomposition. Given analytic radiation predictions, we compare the oscillating string trajectory with a backreaction model accounting for radiation energy losses, finding excellent agreement. We establish that backreaction decay is accurately characterized by the inverse square of the amplitude being proportional to the inverse tension $\mu$ for $3\lesssim \lambda \lesssim 100$. We conclude that analytic radiation modeling in the thin-string (Nambu-Goto) limit provides the appropriate cosmological limit for global strings. We contextualize these results with respect to axions and gravitational waves produced by cosmic string networks.

The cosmic curvature density parameter has been constrained in the present work independent of any background cosmological model. The reconstruction is undertaken adopting the nonparametric Gaussian processes (GP). The constraints on ${\mathrm{\Omega }}_{k0}$ are obtained via a Markov Chain Monte Carlo (MCMC) analysis. Late-time cosmological probes viz., the supernova (SN) distance modulus data, the cosmic chronometer (CC) and the radial baryon acoustic oscillations ($r\mathrm{BAO}$) measurements of the Hubble data have been utilized for this purpose. The results are further combined with the data from redshift space distortions (RSD) which studies the growth of large scale structure in the universe. The only a priori assumption is that the universe is homogeneous and isotropic, described by the Friedmann-Lemaître-Robertson-Walker metric. Results indicate that a spatially flat universe is well consistent in $2\sigma$ within the domain of reconstruction $0<z<2$ for the background data. On combining the RSD data we find that the results obtained are consistent with spatial flatness mostly within $2\sigma$ and always within $3\sigma$ in the domain of reconstruction $0<z<2$.

We present a multiple test for the targeted search of continuous gravitational waves from an ensemble of known pulsars, combining multidetector single pulsar statistics defined through the $5n$-vector method. In order to maximize the detection probability, we describe a rank truncation method to select the most promising sources within the ensemble, based on the p-values computed for single pulsar analysis. To test the efficiency of our method, we use a Monte Carlo procedure and define a p-value for the ensemble that is an overall p-value for the hypothesis of continuous wave emissions from a set of known pulsars. We also perform a pilot search on real data from the O3A dataset of the two LIGO detectors.

We present a five-dimensional (5D) axion-neutrino model that explains the Standard Model fermion mass hierarchy and flavor structure, while simultaneously generating a high-quality axion. The axion and right-handed neutrinos transform under a 5D Peccei-Quinn gauge symmetry, and have highly suppressed profiles on the UV brane where the symmetry is explicitly broken. This setup allows neutrinos to be either Dirac or Majorana with hierarchically small sterile neutrino masses. The axion decay constant originates from the IR scale, which in the holographically dual four-dimensional description corresponds to the confinement scale of some new strong dynamics with a high-quality global Peccei-Quinn symmetry that produces a composite axion and light, composite sterile neutrinos. The sterile neutrinos could be observed in astrophysical or laboratory experiments, and the model predicts specific axion-neutrino couplings.

We present a quantum algorithm for digital quantum simulation of the ${\mathbb{Z}}_2$ gauge–Higgs model on a $3\times 3$ lattice, which is based on Trotter decomposition, the quantum adiabatic algorithm, and its circuit realization. Then, we perform a classical demonstration, dubbed a pseudoquantum simulation, on a GPU simulator. We obtain useful results on this model, which suggest the topological properties of the deconfined phase and help to clarify the phase diagram. It is suggested that the tricitical point, where the second-order critical lines of deconfinement-confinement transition and of deconfinement-Higgs transition meet, seems to be on the first-order critical line of confinement-Higgs transition, at a point other than the end of this critical line.

Using a current-current correlation function, the photon polarization tensor is calculated for a rotating hot and dense QCD medium. The spectral function (SF) and the dilepton rate (DR) are estimated therefrom. Numerical results show that both SF and DR are enhanced in a rotating medium, especially in a low invariant mass region. SF and DR are also explored in the consequences of the interplay among the angular velocity, temperature and chemical potential. We also estimated the electromagnetic screening by calculating the Debye mass and it shows a suppression for a rotating QCD medium. The most interesting observation is the azimuthal anisotropy of the dilepton production, i.e., the elliptic flow $v_2$ of the lepton pair induced by the rotation as an external field. The competition between the centrifugal effect and the spin polarization effect due to rotation results in a convex down behavior of the elliptic flow as a function of the transverse momentum in a relatively large magnitude of angular velocity. It is noticed that quark spin polarization induces a negative $v_2$ in the case of large angular velocity.

The exotic resonant states $P_c^{\pm }(4312)$, $P_c^{\pm }(4440)$, and $P_c^{\pm }(4457)$ are studied using the constrained phase-space coalescence model plus the parton and hadron cascade (paciae) model in $pp$ collisions at $\sqrt{s}=7$, 13 TeV, respectively. The pentaquark states, the nucleuslike states, and the hadronic molecular states are considered as their possible structures based on the $P_c^{\pm }\to J/\psi p(\overline{p})$ bound state. The predictions about the yield, the normalized $p_{\mathrm{T}}$-differential yield, and the normalized rapidity-differential yield are presented for the aforementioned scenarios. The results indicate a hierarchy of the yields for different possible structures; they are all on the order of ${10}^{-6}$. These predictions can be tested by future experimental measurements.