Primordial black holes (PBHs) are one of the most interesting nonparticle dark matter (DM) candidates. They may explain all the DM content in the Universe in the mass regime from about ${10}^{-14}{M}_{\odot }$ to ${10}^{-11}{M}_{\odot }$. We study PBHs as the source of fast radio bursts (FRBs) via magnetic reconnection in the event of collisions between them and neutron stars (NSs) in galaxies. We investigate the energy loss of PBHs during PBH-NS encounters to model their capture by NSs. To an order-of-magnitude estimation, we conclude that the parameter space of PBHs being all DM is accidentally consistent with that to produce FRBs with a rate which is the order of the observed FRB rate.

We explore the vibration isolation requirements imposed by Newtonian noise on the cryogenic shielding for next-generation gravitational-wave observatories relying on radiative cooling. Two sources of Newtonian noise from the shield arrays are analyzed: the tidal coupling from the motion of a shield segment to its nearby test mass’s displacement, and the effect of density fluctuations due to heterogeneous boiling of cryogenic liquids in the vicinity of the test masses. It was determined that the outer shields require no additional vibration isolation from ground motion to mitigate the Newtonian noise coupling to levels compatible with the LIGO Voyager design. Additionally, it was determined that the use of boiling nitrogen as the heat sink for the cryogenic arrays is unlikely to create enough Newtonian noise to compromise the detector performance for either Voyager or Cosmic Explorer phase 2. However, the inherent periodicity of the nucleation cycle might acoustically excite structural modes of the cryogenic array which could contaminate the signals from the interferometer through other means. This last effect could be circumvented by using a single-phase coolant to absorb the heat from the cryogenic shields.

This paper presents the results of a search for generic short-duration gravitational-wave transients in data from the third observing run of Advanced LIGO and Advanced Virgo. Transients with durations of milliseconds to a few seconds in the 24–4096 Hz frequency band are targeted by the search, with no assumptions made regarding the incoming signal direction, polarization, or morphology. Gravitational waves from compact binary coalescences that have been identified by other targeted analyses are detected, but no statistically significant evidence for other gravitational wave bursts is found. Sensitivities to a variety of signals are presented. These include updated upper limits on the source rate density as a function of the characteristic frequency of the signal, which are roughly an order of magnitude better than previous upper limits. This search is sensitive to sources radiating as little as $\sim {10}^{-10}{M}_{\odot }{c}^2$ in gravitational waves at $\sim 70\mathrm{Hz}$ from a distance of 10 kpc, with 50% detection efficiency at a false alarm rate of one per century. The sensitivity of this search to two plausible astrophysical sources is estimated: neutron star $f$ modes, which may be excited by pulsar glitches, as well as selected core-collapse supernova models.

In this paper, we study the entanglement property of a four-particle system. In this system, two initially entangled electrons A and C are scattered by two uncorrelated positrons B and D, respectively. We calculate the entanglements among the particles both before and after the double QED scattering ($AB\to AB,CD\to CD$). We find that the change of entanglement entropy between subsystems A and B during the scattering process is proportional to the total cross section, ${\sigma }_{\mathrm{tot}}={\sigma }_{AB}\times {\sigma }_{CD}$. Even though there is no direct interaction between subsystems A and C (or B and D), the scattering process induces entanglement change among them which is also proportional to ${\sigma }_{\mathrm{tot}}$. This result shows some kind of entanglement sharing property in multipartite system. In order to further investigate the entanglement sharing, we calculate the entanglement monotones that quantify the genuine multipartite entanglement in a multipartite system. For our chosen scattering process, $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$, however, we find that the outgoing state is a W-type four-partite entangled state that has no genuine four-partite entanglement.

Ultraperipheral heavy ion collisions constitute an ideal setup to look for exotic hadrons because of their low event multiplicity and the possibility of an efficient background rejection. We propose to look for four-quark states produced by photon-photon fusion in these collisions at the center-of-mass energy per nucleon pair $\sqrt{s_{\mathrm{NN}}}=5.5\mathrm{TeV}$. In particular, we focus on those states that would represent a definite smoking gun for the compact tetraquark model. We show that the $X(6900)$, a likely $cc\overline{c}\overline{c}$ compact state, is a perfect candidate for this search, and estimate a production cross section ranging from around 250 nb to 1150 nb, depending on its quantum numbers. Furthermore, we discuss the importance of ultraperipheral collisions to the search for the scalar and tensor partners of the $X(3872)$ predicted by the diquarkonium model, and not yet observed. The completion of such a flavor-spin multiplet would speak strongly in favor of the compact tetraquark model.

We explore higher-form symmetries of M- and F-theory compactified on elliptic fibrations, determined by the topology of their asymptotic boundaries. The underlying geometric structures are shown to be equivalent to known characterizations of the gauge group topology in F-theory via Mordell-Weil torsion and string junctions. We further study dimensional reductions of the 11d Chern-Simons term in the presence of torsional boundary $G_4$-fluxes, which encode background gauge fields of center one-form symmetries in the lower-dimensional effective gauge theory. We find contributions that can be interpreted as ’t Hooft anomalies involving the one-form symmetry which originate from a fractionalization of the instanton number of non-Abelian gauge theories in F-/M-theory compactifications to $8\mathrm{d}/7\mathrm{d}$ and $6\mathrm{d}/5\mathrm{d}$.

The formation of primordial black hole (PBH) dark matter and the generation of scalar induced secondary gravitational waves (SIGWs) have been studied in the generic no-scale supergravity inflationary models. By adding an exponential term to the Kähler potential, the inflaton experiences a period of ultraslow-roll and the amplitude of primordial power spectrum at small scales is enhanced to $\mathcal{O}({10}^{-2})$. The enhanced power spectra of primordial curvature perturbations can have both sharp and broad peaks. A wide mass range of PBHs can be produced in our model, and the frequencies of the accompanied SIGWs are ranged form nanohertz to kilohertz. We show four benchmark points where the generated PBH masses are around $\mathcal{O}({10}^{-16}{M}_{\odot })$, $\mathcal{O}({10}^{-12}{M}_{\odot })$, $\mathcal{O}({10}^{-2}{M}_{\odot })$ and $\mathcal{O}({10}^2{M}_{\odot })$. The PBHs with masses around $\mathcal{O}({10}^{-16}{M}_{\odot })$ and $\mathcal{O}({10}^{-12}{M}_{\odot })$ can make up almost all the dark matter, and the accompanied SIGWs can be probed by the upcoming space-based gravitational wave observatory. Also, the SIGWs accompanied with the formation of stellar mass PBHs can be used to interpret the stochastic GW background in the nanohertz band, detected by the North American Nanohertz Observatory for Gravitational Waves, and can be tested by future interferometric gravitational wave observatory.

We perform the first study of the principal core $g$-mode oscillation in hybrid stars containing quark matter, utilizing a crossover model for the hadron-to-quark transition inspired by lattice QCD. The ensuing results are compared with our recent findings of $g$-mode frequencies in hybrid stars with a first-order phase transition using Gibbs constructions. We find that models using Gibbs construction yield $g$-mode amplitudes and the associated gravitational energy radiated that dominate over those of the chosen crossover model owing to the distinct behaviors of the equilibrium and adiabatic sound speeds in the various models. Based on our results, we conclude that were $g$ modes to be detected in upgraded LIGO and Virgo detectors it would indicate a first-order phase transition akin to a Gibbs construction.

Dark matter (DM) can be trapped by the gravitational field of any star, since collisions with nuclei in dense environments can slow down the DM particle below the escape velocity ($v_{\mathrm{esc}}$) at the surface of the star. If captured, the DM particles can self-annihilate, and, therefore, provide a new source of energy for the star. We investigate this phenomenon for capture of DM particles by the first generation of stars [Population III (Pop III) stars], by using the multiscatter capture formalism. Pop III stars are particularly good DM captors, since they form in DM-rich environments, at the center of $\sim {10}^6{M}_{\odot }$ DM minihalos, at redshifts $z\sim 15$. Assuming a DM-proton scattering cross section ($\sigma$) at the current deepest exclusion limits provided by the XENON1T experiment, we find that captured DM annihilations at the core of Pop III stars can lead, via the Eddington limit, to upper bounds in stellar masses that can be as low as a few $M_{\odot }$ if the ambient DM density (${\rho }_X$) at the location of the Pop III star is sufficiently high. Conversely, when Pop III stars are identified, one can use their observed mass ($M_{\star }$) to place bounds on ${\rho }_X\sigma$. Using adiabatic contraction to estimate the ambient DM density in the environment surrounding Pop III stars, we place projected upper limits on $\sigma$, for $M_{\star }$ in the $100M_{\odot }–1000M_{\odot }$ range, and find bounds that are competitive with, or deeper than, those provided by the most sensitive current direct detection experiments for both spin-independent and spin-dependent (SD) interactions, for a wide range of DM masses. Most intriguingly, we find that Pop III stars with mass $M_{\star }\gtrsim 300M_{\odot }$ could be used to probe the SD proton-DM cross section below the “neutrino floor,” i.e. the region of parameter space where DM direct detection experiments will soon become overwhelmed by neutrino backgrounds.

Faster likelihood evaluation enhances the efficiency of gravitational wave signal analysis. We present mode-by-mode relative binning, a new method designed for obtaining fast and accurate likelihoods for advanced waveform models that include spin-orbit precession effects and multiple radiation harmonics from compact binary coalescence. Leveraging the “twisting-up” procedure of constructing precessing waveform modes from nonprecessing ones, the new method mitigates degrade of relative binning accuracy due to interference from superimposed modes. Additionally, we supplement algorithms for optimizing the choice of frequency bins specific to any given strain signal under analysis. Using the new method, we are able to evaluate the likelihood with up to an order of magnitude reduction in the number of waveform model calls per frequency compared to the previously used relative binning scheme, and achieve better likelihood accuracy than is sufficient for obtaining source parameter posterior distributions that are indistinguishable from the exact ones.

In this paper we compare the experimental HERA data with the next-to-leading order approach (NLO) of [Eur. Phys. J. C 80, 1029 (2020)]. This approach includes the re-summed NLO corrections to the kernel of the evolution equation, the correct asymptotic behavior in the NLO at $\tau =r^2{Q}_s^2\gg 1$; the impact parameter dependence of the saturation scale in accord with the Froissarrt theorem as well as the nonlinear corrections. In this paper, we successfully describe the experimental data with the quality, which is not worse, than in the leading order fits with larger number of the phenomenological parameters. It is demonstrated, that the data could be described, taking into account both the diffusion on $\ln (k_T)$, which stems from perturbative QCD, and the Gribov’s diffusion in impact parameters. It is shown an ability to describe the data at rather large values of ${\overline{\alpha }}_S$.

The Glashow-Iliopoulos-Maiani mechanism is extremely efficient to suppress the flavor-changing neutral current decays of charmed hadrons induced by the $c\to u$ transitions, making such processes particularly sensitive to phenomena beyond the Standard Model. In particular, $c\to u$ decays with a neutrino pair in the final state are theoretically appealing due to the small long-distance contributions. Moreover, in the framework of the Standard Model effective field theory (SMEFT), the $SU(2{)}_L$ invariance allows us to relate the Wilson coefficients in the effective Hamiltonian governing the $c\to u\nu \overline{\nu }$ decays to the coefficients in the $c\to u{\ell }^{+}{\ell }^{-}$ Hamiltonian. We analyze the $B_c\to B^{(*)+}\nu \overline{\nu }$ decays, for which branching fractions of at most $\mathcal{O}({10}^{-16})$ are predicted in the Standard Model including short- and long-distance contributions, so small that they can be considered as null tests. Using SMEFT and the relation to the $c\to u{\ell }^{+}{\ell }^{-}$ processes, we study the largest enhancement achievable in generic new physics scenarios, then we focus on a particular extension of the Standard Model, the 331 model. SMEFT relations and the connection with $c\to u{\ell }^{+}{\ell }^{-}$ imply that $\mathcal{B}(B_c\to B^{(*)+}\nu \overline{\nu })$ could even reach $\mathcal{O}({10}^{-6})$, an extremely large enhancement. A less pronounced effect is found in the 331 model, with $\mathcal{O}({10}^{-11})$ predicted branching fractions. Within the 331 model, correlations exist among the $B_c\to B^{(*)+}\nu \overline{\nu }$ and $K\to \pi \nu \overline{\nu }$, $B\to (X_s,K,K^{*})\nu \overline{\nu }$ channels.

We study the sensitivity of future xenon- and argon-based dark matter and neutrino detection experiments to low-energy atmospheric neutrinos. Not accounting for experimental backgrounds, the primary obstacle for identifying nuclear recoils induced by atmospheric neutrinos in xenon is the tail of the electron recoil distribution due to $pp$ solar neutrinos. We use the NEST code to model the solar and atmospheric neutrino signals in a xenon detector and find that an exposure of 700 tonne-years will produce a $5\sigma$ detection of atmospheric neutrinos. We explore the effect of different detector properties and find that a sufficiently long electron lifetime is essential to the success of such a measurement.

Finite-size scaling is investigated in detail around the critical point in the heavy quark region of nonzero temperature QCD. Numerical simulations are performed with large spatial volumes up to the aspect ratio $N_s/N_t=12$ at a fixed lattice spacing with $N_t=4$. We show that the Binder cumulant and the distribution function of the Polyakov loop follow the finite-size scaling in the $Z(2)$ universality class for large spatial volumes with $N_s/N_t\ge 9$, while, for $N_s/N_t\le 8$, the Binder cumulant becomes inconsistent with the $Z(2)$ scaling. To realize the large-volume simulations in the heavy quark region, we adopt the hopping parameter expansion for the quark determinant: We generate gauge configurations using the leading-order action including the Polyakov loop term for $N_t=4$, and incorporate the next-to-leading order effects in the measurements by the multipoint-reweighting method. We find that the use of the leading-order configurations is crucially effective in suppressing the overlapping problem in the reweighting and thus in reducing the statistical errors.

We present continuum extrapolated results of charmonium and bottomonium correlators in the vector channel at several temperatures below and above $T_c$. The continuum extrapolation jointly performed with the interpolations to have physical values of $J/\psi$ and $\mathrm{\Upsilon }$ masses in the confined phase is based on calculations on several large quenched isotropic lattices using clover-improved Wilson valence fermions carrying different quark masses. The extrapolated lattice correlators are confronted with perturbation theory results incorporating resummed thermal effects around the threshold from potential nonrelativistic QCD (pNRQCD) and vacuum asymptotics above the threshold. An additional transport peak is modeled below the threshold allowing for an estimate of the diffusion coefficients for charm and bottom quarks. We find that charmonium correlators in the vector channel can be well reproduced by perturbative spectral functions above $T_c$ where no resonance peaks for $J/\psi$ are needed at and above $1.1T_c$, while for bottomonium correlators a resonance peak for $\mathrm{\Upsilon }$ is still needed up to $1.5T_c$. By analyzing the transport contribution to the correlators we find that the drag coefficient of a charm quark is larger than that of a bottom quark.

We apply the dynamical diquark model to predict the spectrum of hidden-charm pentaquark states in both unflavored and open-strange sectors. Using only Hamiltonian parameters introduced in the tetraquark $S$- and $P$-wave multiplets, the model naturally produces the level spacing supported by the most recent LHCb results for $P_c$ structures. Furthermore, using model inputs obtained from data of hidden-charm, open-strange tetraquarks ($Z_{cs}$), we predict the spectrum of $P_{cs}$ states, including the recently observed $P_{cs}(4459)$. We find all pentaquark candidates observed to date to belong to the $1P$ multiplet and hence have positive parity.

We explore the implications of the recent radius determination of PSR $\mathrm{J}0740+6620$ by the NICER experiment, combined with the neutron skin measurement by the PREX-II experiment and the associated inference of the slope of symmetry energy, for the structure of hybrid stars with a strong first-order phase transition from nucleonic to quark matter. We combine a covariant density-functional nucleonic equation of state (EOS) with a constant-speed-of-sound EOS for quark matter. We show that the radius and tidal deformability ranges obtained from GW170817 can be reconciled with the implication of the PREX-II experiment if there is a phase transition to quark matter in the low-mass compact star. In the high-mass segment, the EOS needs to be stiff to comply with the large-radius inference for PSR $\mathrm{J}0740+6620$ and $\mathrm{J}0030+0451$ with masses $M\simeq 2M_{\odot }$ and $M\simeq 1.4M_{\odot }$. We show that twin stars are not excluded, but the mass and radius ranges (with $M\ge M_{\odot }$) are restricted to narrow domains $\mathrm{\Delta }{M}_{\mathrm{twin}}\lesssim 0.05M_{\odot }$ and $\mathrm{\Delta }{R}_{\mathrm{twin}}\sim 1.0\mathrm{km}$. We also show that the existence of twin configurations is compatible with the light companion in the GW190814 event being a hybrid star in the case of values of the sound-speed square $s=0.6$ and $s=1/3$.

We study a systematic derivation of four-dimensional $\mathcal{N}=1$ supersymmetric effective theory from a ten-dimensional non-Abelian Dirac-Born-Infeld action compactified on a six-dimensional torus with magnetic fluxes on the D-branes. We find a new type of matter Kähler metric, while gauge kinetic function and superpotential are consistent with previous studies. For the ten-dimensional action, we use a symmetrized trace prescription and focus on the bosonic part up to $\mathcal{O}(F^4)$. In the presence of the supersymmetry, four-dimensional chiral fermions can be obtained via index theorem. The new matter Kähler metric is independent of flavor but depends on the fluxes, 4D dilaton, Kähler moduli, and complex structure moduli and will be always positive definite if an induced Ramond-Ramond charge of the D-branes on which matters are living are positive. We read the superpotential from an F-term scalar quartic interaction derived from the ten-dimensional action and the contribution of the new matter Kähler metric to the scalar potential which we derive turns out to be consistent with the supergravity formulation.

We investigate how entangled inertial Unruh-DeWitt detectors are affected by interaction with a quantum field using a nonperturbative method. Inertial detectors in a ($3+1$)-dimensional Minkowski spacetime with instantaneous switching ($\delta$-switching) experience degradation of their initial entanglement as their coupling strength with a scalar field increases. Somewhat surprisingly, initially separable or weakly entangled detectors can extract mutual information from the vacuum. We also find that entanglement degradation is not reduced if communication via the field is possible; rather this only changes the manner in which entanglement is degraded.