Large panels of etched plastic, situated aboard the Skylab Space Station and inside the Ohya quarry near Tokyo, have been used to set limits on fluxes of cosmogenic particles. These plastic particle track detectors also provide the best sensitivity for some heavy dark matter that interacts strongly with nuclei. We revisit prior dark matter bounds from Skylab, and incorporate geometry-dependent thresholds, a halo velocity distribution, and a complete accounting of observed through-going particle fluxes. These considerations reduce the Skylab bound’s mass range by a few orders of magnitude. However, a new analysis of Ohya data covers a portion of the prior Skylab bound, and excludes dark matter masses up to the Planck mass. Prospects for future etched plastic dark matter searches are discussed.

A network of synchronized detectors can increase the likelihood of discovering the QCD axion within the axion quark nugget (AQN) dark matter model. A similar network can also discriminate the x rays emitted by the AQNs from the background signal. These networks can provide information on the directionality of the dark matter flux (if any), as well as its velocity distribution, and can therefore test the Standard Halo Model. We show that the optimal configuration to detect AQN-induced axions is a triangular network of stations 100 km apart. For x rays, the optimal network is an array of tetrahedral units.

I make two comments about nuclear matter. First, I consider the effects of a coupling between the $O(4)$ chiral field, $\overrightarrow{\varphi }$, and the ${\omega }_{\mu }$ meson, $\sim +{\overrightarrow{\varphi }}^2{\omega }_{\mu }^2$; for any net baryon density, a condensate for ${\omega }_0$ is unavoidably generated. I assume that with increasing density, a decrease of the chiral condensate and the effective ${\omega }_0$ mass gives a stiff equation of state (EOS). In order to match that onto a soft EOS for quarkyonic matter, I consider an $O(N)$ field at large $N$, where at nonzero temperature quantum fluctuations disorder, any putative pion “condensates” into a quantum pion liquid ($\mathrm{Q}\pi \mathrm{L}$) [R. D. Pisarski et al., Phys. Rev. D 102, 016015 (2020)]. In this paper, I show that the $\mathrm{Q}\pi \mathrm{L}$ persists at zero temperature. If valid qualitatively at $N=4$, the ${\omega }_0$ mass goes up sharply and suppresses the ${\omega }_0$ condensate. This could generate a spike in the speed of sound at high density, which is of relevance to neutron stars. Second, I propose a toy model of a $Z(3)$ gauge theory with three flavors of fermions, where $Z(3)$ vortices confine fermions into baryons. In $1+1$ dimensions, this model can be studied numerically with present techniques, using either classical or quantum computers.

Extending our recently published SU(2) results for zero temperature, we now compute the QCD equation of state for finite isospin density within the three-flavor Nambu–Jona-Lasinio (NJL) model in the mean field approximation, motivated by the recently obtained lattice QCD results for both zero and finite temperatures. Like our previous study, here also we have considered both the commonly used traditional cutoff regularization scheme and the medium separation scheme. Our results are compared with recent high-precision lattice simulations as well as previously obtained results in two-flavor Nambu–Jona-Lasinio model. The agreement between the lattice results and the predictions from three-flavor NJL model is very good for low values of ${\mu }_I$ (for both zero and finite temperatures). For larger values of ${\mu }_I$, the agreement between lattice data and the two-flavor NJL predictions is surprisingly good and better than with the three-flavor predictions.

The associated production of a single-top with opposite-sign same-flavor (OSSF) dileptons, $pp\to t{\ell }^{+}{\ell }^{-}$ and $pp\to t{\ell }^{+}{\ell }^{-}+j$ ($j=\mathrm{light}\mathrm{jet}$), can lead to striking trilepton $pp\to {\ell }^{\prime }{\ell }^{+}{\ell }^{-}+X$ and dilepton $pp\to {\ell }^{+}{\ell }^{-}+j_b+X$ ($j_b=b\text{−}\mathrm{jet}$) events at the LHC, after the top decays. Although these rather generic multilepton signals are flavor-blind, they can be generated by new 4-Fermi flavor changing (FC) $u_{i}t\ell \ell$ scalar, vector and tensor interactions ($u_i\in u$, $c$), which we study in this paper; we match the FC $u_{i}t\ell \ell$ 4-Fermi terms to the SMEFT operators and also to different types of FC underlying heavy physics. The main backgrounds to these di- and trilepton signals arise from $t\overline{t}$, $Z+\text{jets}$ and $VV$ ($V=W$, $Z$) production, but they can be essentially eliminated with a sufficiently high invariant mass selection on the OSSF dileptons, $m_{{\ell }^{+}{\ell }^{-}}^{\mathsf{min}}(\mathrm{OSSF})\gtrsim 1\mathrm{TeV}$; the use of $b$-tagging as an additional selection in the dilepton final state case also proves very useful. We find, for example, that the expected 95% CL bounds on the scale of a tensor(vector) $ut\mu \mu$ interaction, with the current $\sim 140{\mathrm{fb}}^{-1}$ of LHC data, are $\mathrm{\Lambda }\lesssim 5(3.2)\mathrm{TeV}$ or $\mathrm{\Lambda }\lesssim 4.1(2.7)\mathrm{TeV}$, if analyzed via the dimuon ${\mu }^{+}{\mu }^{-}+j_b$ signal or the $e{\mu }^{+}{\mu }^{-}$ trilepton one, respectively. The expected reach at the HL-LHC with $3000{\mathrm{fb}}^{-1}$ of data is $\mathrm{\Lambda }\lesssim 7.1(4.7)\mathrm{TeV}$ and $\mathrm{\Lambda }\lesssim 2.4(1.5)\mathrm{TeV}$ for the corresponding $ut\mu \mu$ and $ct\mu \mu$ operators. This should be compared to the current bounds of $\mathrm{\Lambda }\lesssim \mathcal{O}(1)\mathrm{TeV}$ on both the $ut\ell \ell$ and $ct\ell \ell$ operators from LEP2 and from $pp\to t\overline{t}$ followed by $t\to {\ell }^{+}{\ell }^{-}j$. We also study the potential sensitivity at future 27 TeV and 100 TeV high-energy LHC successors, which, for the $ut\ell \ell$ operators, can reach $\mathrm{\Lambda }\sim 10–40\mathrm{TeV}$. We furthermore discuss the possible implications of this class of FC 4-Fermi effective interactions on lepton nonuniversality tests at the LHC.

Using numerical solutions to the Dirac equation, we examine the role of energy shifts on the energy spectrum of created positrons in the laser-induced electron-positron pair-creation process in the presence of a highly charged model nucleus. We suggest that at those laser intensities, where the created electrons can be captured by the nucleus, the inclusion of the field-induced energy level shifts is crucial to predict correct positron energy spectra, especially close to the threshold for this process with regard to the laser frequency. For the interesting case where the laser frequency is tuned to the bound state energy differences, the coherence associated with possible electronic Rabi oscillations is transferred to the generated positrons, leading to new split peaks in their energy spectrum.

Quantum chromodynamics presents a series of exact and approximate symmetries which can be exploited to predict new hadrons from previously known ones. The $Z_c(3900)$ and $Z_c(4020)$, which have been theorized to be isovector $D^{*}\overline{D}$ and $D^{*}{\overline{D}}^{*}$ molecules [$I^G(J^{PC})=1^{-}(1^{+-})$], are no exception. Here we argue that from SU(3)-flavor symmetry, we should expect the existence of strange partners of the $Z_c$’s with hadronic molecular configurations $D^{*}{\overline{D}}_s-D{\overline{D}}_s^{*}$ and $D^{*}{\overline{D}}_s^{*}$ (or, equivalently, quark content $c\overline{c}s\overline{q}$, with $q=u$, $d$). The quantum numbers of these $Z_{cs}$ and $Z_{cs}^{*}$ structures would be $I(J^P)=\frac{1}{2}(1^{+})$. The predicted masses of these partners depend on the details of the theoretical scheme used, but they should be around the $D^{*}{\overline{D}}_s-D{\overline{D}}_s^{*}$ and $D^{*}{\overline{D}}_s^{*}$ thresholds, respectively. Moreover, any of these states could be either a virtual pole or a resonance. We show that, together with a possible triangle singularity contribution, such a picture nicely agrees with the very recent BESIII data of the $e^{+}{e}^{-}\to K^{+}(D_s^{-}{D}^{*0}+D_s^{*-}{D}^0)$.

We propose a modified definition of the jet charge, the “dynamic jet charge,” where the constant jet momentum fraction weighting parameter $\kappa$ in the standard jet charge definition is generalized to be a function of a dynamical property of the jet or the individual jet constituents. The dynamic jet charge can complement analyses based on the standard definition and give improved discrimination between quark and gluon initiated jets and between jets initiated by different quark flavors. We focus on the specific scenario where each hadron in the jet contributes to the dynamic jet charge with a $\kappa$-value dynamically determined by its jet momentum fraction. The corresponding dynamic jet charge distributions have qualitatively distinct features and are typically characterized by a multiple peak structure. For proton-proton collisions, compared to the standard jet charge, the dynamic jet charge gives significantly improved discrimination between quark and gluon initiated jets and comparable discrimination between $u$- and $d$-quark initiated jets. In pythia simulations of heavy ion collisions, the dynamic jet charge is found to have higher jet discrimination power compared to the standard jet charge, remaining robust against the increased contamination from underlying event. We also present phenomenological applications of the dynamic jet charge to probe nuclear flavor structure.

The BPS bound states of D4-D2-D0 branes on the noncompact divisors of Calabi-Yau threefolds and the instantons in the dual quiver gauge theories are previously studied using two-dimensional crystal melting model and dimer model, [T. Nishinaka et al., J. High Energy Phys. 5 (2014) 139]. Using the tropical geometry associated with the toric quiver, we study the asymptotic of the quiver gauge theory to compute some of their thermodynamic observables and extract the phase structure. We obtain that the thermodynamic observables such as free energy, entropy, and growth rate are explicitly derived from the limit shape of the crystal model, the boundary of the amoeba and its Harnack curve characterization. Furthermore, we observe that there is a Hagedorn phase transition in the instanton sector inferred from the Gumbel distribution of the fluctuations in the crystal model. We present explicit computations of the results in concrete examples of ${\mathbb{C}}^3$, conifold, local ${\mathbb{P}}^1\times {\mathbb{P}}^1$ and local ${\mathbb{P}}^2$ quivers.

We study several deformations of the Skyrme model in three dimensions with self-dual sectors of arbitrary baryonic charge. We show that, for a family of background metrics as well as for a family of field dependent couplings, the model has one BPS sector, which may have any topological charge. We also study the gravitating case, where there are infinite BPS sectors, provided that a cosmological constant is added to the model.

We consider a timelike geodesics in the background of rotating Einstein-Born-Infeld (EBI) black hole to examine the horizon and ergosphere structure. The effective potential that governs the particle’s motion in the spacetime and the innermost stable circular orbits (ISCO) is also studied. A qualitative analysis is conducted to find the redshifted ultrahigh center-of-mass (CM) energy as a result of a two-particle collision specifically near the horizon. The recent Event Horizon Telescope (EHT) triggered a surge of interest in strong gravitational lensing by black holes, which provide a new tool comparing the black hole lensing in general relativity and alternate gravity theories. Motivated by this, we also discussed both strong and weak-field gravitational lensing in the space-time discretely for a uniform plasma and a singular isothermal sphere. We calculated the light deflection coefficients $\overline{a}$ and $\overline{b}$ in the strong field limits, and their variance with the rotational parameter $a$ for different plasma frequency as well as in vacuum. For EBI black holes, we found that plasma’s presence increases the photon sphere radius, the deflection angle, the deflection coefficients $\overline{a}$, $\overline{b}$, the angular positions and the angular separation between the relativistic images. It is also shown that with increasing spin the impact of plasma on a strong gravitational lensing becomes smaller as the spin parameter grows in the prograde orbit ($a>0$). For extreme black holes, the strong gravitational effects in the homogenous plasma are similar to those of in a vacuum. We investigate strong gravitational lensing effects by supermassive black holes Sgr A* and M87*. Considering rotating EBI black holes as the lens, we find the angular position of images for Sgr A* and M87* and observe that the deviations of the angular position from that of the analogous Kerr black hole are not more than $2.44\mu \mathrm{as}$ for Sgr A* and $1.83\mu \mathrm{as}$ for M87*, which are unlikely to get resolved by the current EHT observations.

We consider a further extension of our previous works in the treatment of the three-dimensional general relativistic Poynting-Robertson effect, which describes the motion of a test particle around a compact object as affected by the radiation field originating from a rigidly rotating and spherical emitting source, which produces a radiation pressure, opposite to the gravitational pull, and a radiation drag force, which removes energy and angular momentum from the test particle. The gravitational source is modeled as a nonspherical and slowly rotating compact object endowed with a mass quadrupole moment and an angular momentum and it is formally described by the Hartle-Thorne metric. We derive the test particle’s equations of motion in the three-dimensional and two-dimensional cases. We then investigate the properties of the critical hypersurfaces (regions where a balance between gravitational and radiation forces is established). Finally, we show how this model can be applied to treat radiation phenomena occurring in the vicinity of a neutron star.

We examine the post-Newtonian limit of the minimal exponential measure (MEMe) model presented in [J. C. Feng, S. Carloni, Phys. Rev. D 101, 064002 (2020)] using an extension of the parameterized post-Newtonian (PPN) formalism which is also suitable for other type-I minimally modified gravity theories. The new PPN expansion is then used to calculate the monopole term of the post-Newtonian gravitational potential and to perform an analysis of circular orbits within spherically symmetric matter distributions. The latter shows that the behavior does not differ significantly from that of general relativity for realistic values of the MEMe model parameter $q$. Instead the former shows that one can use precision measurements of Newton’s constant $G$ to improve the constraint on $q$ by up to 10 orders of magnitude.

We obtain the mass parameter for a class of static and spherically symmetric regular black holes (BHs) (namely Bardeen, Hayward and Ayón-Beato-García BHs) which are solutions of Einstein’s field equations coupled to nonlinear electrodynamics (NED) in terms of redshifts and blueshifts of photons emitted by geodesic particles (for instance, stars) orbiting around these BHs. The motion of photons is not governed by null geodesics for these type of spacetime geometries which reflects the direct effects of the electrodynamic nonlinearities in the photon motion; hence, an effective geometry needs to be constructed to study null trajectories [M. Novello et al., Phys. Rev. D 61, 045001 (2000)]. To achieve the above, we first study the constants of motion from the analysis of the motion of both geodesic particles moving in stable circular orbits and photons ejected from them and reaching a distant observer (or detector) in the equatorial plane for the above mentioned regular BHs. The relationship between red/blueshifts of photons and the regular BH observables is presented. We also numerically find the bounds on the photon shifts for these regular BH cases.

Nowadays, fast radio bursts (FRBs) have been a promising probe for astronomy and cosmology. However, it is not easy to identify the redshifts of FRBs to date. Thus, no sufficient actual FRBs with identified redshifts can be used to study cosmology currently. In the past years, one has to use the simulated FRBs with “known” redshifts instead. To simulate an FRB, one should randomly assign a redshift to it from a given redshift distribution. But the actual redshift distribution of FRBs is still unknown so far. Therefore, many redshift distributions have been assumed in the literature. In the present work, we study the effect of various redshift distributions on cosmological constraints, while they are treated equally. We find that different redshift distributions lead to different cosmological constraining abilities from the simulated FRBs. This result emphasizes the importance to find the actual redshift distribution of FRBs, and reminds us of the possible bias in the FRB simulations due to the redshift distributions.

In recent years, the scalar field dark matter (SFDM), also called ultralight bosonic dark matter, has received considerable attention due to the number of problems it might help to solve. Among these are the cusp-core problem and the abundance of small structures of the standard cold dark matter (CDM) model. In this paper we show that multi-state solutions of the low energy and weak gravitational field limit of field equations, interpreted as galactic halo density profiles, can provide a possible explanation to the anisotropic distribution of satellite galaxies observed in the Milky Way, M31 and Centaurus A, where satellites trajectories seem to concentrate on planes close to the poles of the galaxies instead of following homogeneously distributed trajectories. The core hypothesis is that multi-state solutions of the equations describing the dynamics of this dark matter candidate, namely, the Gross-Pitaevskii-Poisson equations, with monopolar and dipolar contributions, can possibly explain the anisotropy of satellite trajectories. In order to construct a proof of concept, we study the trajectories of a number of test particles traveling on top of the gravitational potential due to a multi-state halo with modes $(1,0,0)+(2,1,0)$. The result is that particles accumulate asymptotically in time on planes passing close to the poles. Satellite galaxies are not test particles but interpreted as such, our results indicate that in the asymptotic time their trajectories do not distribute isotropically, instead they prefer to have orbital poles accumulating near the equatorial plane of the multistate halo. The concentration of orbital poles depends on whether the potential is monopolar or dipolar dominated.

Practical calculations in light-front dynamics are, as a general rule, complicated, since there is no consensus about how to treat the poles which come from the instantaneous parts of Feynman’s propagators of the fields. An alternative to solve this difficulty is null-plane causal perturbation theory, a recent developed framework which prevents the appearance of the mentioned poles by avoiding the usage of Feynman’s propagators in “loop distributions,” requiring no regularization of the amplitudes. In this study, we treat the radiative corrections in the neutral Yukawa’s model in that framework. Particularly, we explicitly calculate the boson and fermion self-energies and show that the results obtained with this approach are equivalent to that of the instant dynamics.

Indirect detection experiments typically measure the flux of annihilating dark matter (DM) particles propagating freely through galactic halos. We consider a new scenario where celestial bodies “focus” DM annihilation events, increasing the efficiency of halo annihilation. In this setup, DM is first captured by celestial bodies, such as neutron stars or brown dwarfs, and then annihilates within them. If DM annihilates to sufficiently long-lived particles, they can escape and subsequently decay into detectable radiation. This produces a distinctive annihilation morphology, which scales as the product of the DM and celestial body densities, rather than as DM density squared. We show that this signal can dominate over the halo annihilation rate in $\gamma$-ray observations in both the Milky Way Galactic center and globular clusters. We use Fermi and H.E.S.S. data to constrain the DM-nucleon scattering cross section, setting powerful new limits down to $\sim {10}^{-39}{\mathrm{cm}}^2$ for sub-GeV DM using brown dwarfs, which is up to 9 orders of magnitude stronger than existing limits. We demonstrate that neutron stars can set limits for TeV-scale DM down to about ${10}^{-47}{\mathrm{cm}}^2$.

We consider the production of a “fast flux” of hypothetical millicharged particles (mCPs) in the interstellar medium. We consider two possible sources induced by cosmic rays: (a) $pp\to (\mathrm{meson})\to (\mathrm{mCP})$, which adds to atmospheric production of mCPs, and (b) cosmic-ray upscattering on a millicharged component of dark matter. We notice that the galactic magnetic fields retain mCPs for a long time, leading to an enhancement of the fast flux by many orders of magnitude. In both scenarios, we calculate the expected signal for direct dark matter detection aimed at electron recoil. We observe that in scenario (a) neutrino detectors (ArgoNeuT and Super-Kamiokande) still provide superior sensitivity compared to dark matter detectors (XENON1T). However, in scenarios with a boosted dark matter component, the dark matter detectors perform better, given the enhancement of the upscattered flux at low velocities. Given the uncertainties, both in the flux generation model and in the actual atomic physics leading to electron recoil, it is still possible that the XENON1T-reported excess may come from a fast mCP flux, which will be decisively tested with future experiments.