We study the orbital evolution of eccentric binary systems in Horndeski gravity. This particular theory provides a test bed to give insightful comparisons with data. We compute the rate of energy loss and the rate of change of angular momentum for the binaries by calculating the multipole moments of the radiation fields. We have used appropriate parameters for the eccentric binaries to compute the decay rates of its orbital eccentricity and semimajor axis. We then compare this decay rate with that of general relativity.

Doubly special relativity (DSR) theories consider (quantum-gravity motivated) deformations of the symmetries of special relativity compatible with a relativity principle. The existence of time delays for massless particles, one of their proposed phenomenological consequences, is a delicate question since, contrary to what happens with Lorentz invariance violation scenarios, they are not simply determined by the modification in the particle dispersion relation. While some studies of DSR assert the existence of photon time delays, in this paper we generalize a recently proposed model for time delay studies in DSR and show that the existence of photon time delays does not necessarily follow from a DSR scenario, determining in which cases this is so. Moreover, we clarify long-standing questions about the arbitrariness in the choice of the energy-momentum labels and the independence of the time delay on this choice, as well as on the consistency of its calculation with the relative locality paradigm of DSR theories. Finally, we show that the result for time delays is reproduced in models that consider propagation in a noncommutative spacetime.

Orbits of Finslerian Schwarzschild black hole have been investigated in this paper. The Finslerian Schwarzschild black hole is a warp product spacetime where its two dimensional subspace possesses constant Finslerian curvature. Due to this special geometrical structure, four constants of motion have been obtained from geodesic equations of Finslerian Schwarzschild spacetime. Finslerian parameter $\epsilon$ which describes deviation between Finslerian Schwarzschild black hole and Schwarzschild black hole affects both orbital precession and orbital plane precession. Orbit of Finslerian Schwarzschild black hole will ergodically fill a toruslike region. It is shown that the orbital precession of Finslerian Schwarzschild black hole is a constant if we calculate the two nearby perihelion of orbit by arc length of two dimensional subspace of Finslerian Schwarzschild black hole. However, present astronomical observations calculate the two nearby perihelion of orbit by arc length of Riemannian 2-sphere. Under this viewpoint, the orbital precession of Finslerian Schwarzschild black hole will depend on the Finslerian parameter and orbital elements. Observations of orbits of several stars around Sagittarius A* by GRAVITY collaboration provide an approach to falsify Finslerian Schwarzschild black hole. We have used data of orbital precession of the star S2 as an anchor to constrain the Finslerian parameter. The value of $\epsilon$ is range from $-1.42\times {10}^{-4}$ to $1.66\times {10}^{-4}$. Then, we used the constrained $\epsilon$ to give prediction of orbital precession of other stars around Sagittarius A*. Due to the parity symmetry violation, it is shown in numerical results that both the direction of motion and the sign of $\epsilon$ will affect the orbital precession.

We study aspects of inflation and the possibility of enhanced production of primordial black holes (PBHs) and gravitational waves (GWs) in a string-inspired model of two axion fields coupled to Chern-Simons gravity, which results in a running-vacuum-model inflation. Fluctuations of the scale-invariant spectrum, consistent with the cosmological data, are provided in this model by world-sheet (nonperturbative) instanton terms of the axion field arising from string compactification. As a result of such modulations, there is an enhanced production of PBHs and GWs in such cosmologies, which may lead to observable in principle patterns in the profile of GWs during the radiation era. Moreover, we demonstrate that the PBHs may provide a significant amount of dark matter in this Universe. For comparison, we also discuss a two-stage inflation cosmological model of conventional string-inspired axion monodromy, involving again two axion fields. The resulting modifications imprinted on the GWs spectra between these two classes of models are distinct, and can, in principle, be distinguished by future interferometers. We consider models with more or less instantaneous reheating. We also make some remarks on the effects of a prolonged reheating period in leading to further enhancement of the power spectrum and thus fractions of PBHs that play the role of dark matter.

We study the use of type Ia supernovae (SNe Ia) in the context of scalar-tensor theories of gravity, taking as a working example induced gravity, equivalent to Jordan-Brans-Dicke theory. Winking at accurate and precision cosmology, we test the correction introduced by a time variation of the Newton constant, predicted by scalar-tensor theories, on the SNe distance modulus relation. We find that for induced gravity the coupling parameter is constrained from $\xi <0.0095$ [95% confidence level (CL)] using Pantheon SNe data alone down to $\xi <0.00063$ (95% CL) in combination with Planck data release DR3 and a compilation of baryon acoustic oscillation (BAO) measurements from BOSS DR12. In this minimal case the improvements in terms of constraints on the cosmological parameters coming from the addition of SNe data to cosmic microwave background (CMB) and BAO measurements is limited, $\sim 7\%$ on the 95% CL upper bound on $\xi$. Allowing for the value of the gravitational constant today to depart from the Newton constant, we find that the addition of SNe further tightens the constraints obtained by CMB and BAO data on the standard cosmological parameters and by 22% on the coupling parameter, i.e., $\xi <0.00064$ at 95% CL We finally show that in this class of modified gravity models the use of a prior on the absolute magnitude $M_B$ in combination with the Pantheon SNe sample leads to results which are very consistent with those obtained by imposing a prior on $H_0$, as happens for other early type models which accommodate a larger value of $H_0$ compared to the $\mathrm{\Lambda }\mathrm{CDM}$ results.

Many theoretical resolutions to the so-called “Hubble tension” rely on modifying the sound horizon at recombination, $r_s$, and thus the acoustic scale used as a standard ruler in the cosmic microwave background (CMB) and large scale structure (LSS) datasets. As shown in a number of recent works, these observables can also be used to compute $r_s$-independent constraints on $H_0$ by making use of the horizon scale at matter-radiation equality, $k_{\mathrm{eq}}$, which has different sensitivity to high redshift physics than $r_s$. As such, $r_s$- and $k_{\mathrm{eq}}$-based measurements of $H_0$ (within a $\mathrm{\Lambda }\mathrm{CDM}$ framework) may differ if there is new physics present pre-recombination. In this work, we present the tightest constraints on the latter from current data, finding $H_0={64.8}_{-2.5}^{+2.2}\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ at 68% CL from a combination of BOSS galaxy power spectra, Planck CMB lensing, and the newly released pantheon+ supernova constraints, as well as physical priors on the baryon density, neutrino mass, and spectral index. The BOSS and Planck measurements have different degeneracy directions, leading to the improved combined constraints, with a bound of $H_0={67.1}_{-2.9}^{+2.5}$ (${63.6}_{-3.6}^{+2.9}$) from BOSS (Planck) alone in $\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ units. The results show some dependence on the neutrino mass bounds, with the constraint broadening to $H_0={68.0}_{-3.2}^{+2.9}\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ if we instead impose a weak prior on $\sum m_{\nu }$ from terrestrial experiments rather than assuming $\sum m_{\nu }<0.26\mathrm{eV}$, or shifting to $H_0=64.6\pm 2.4\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ if the neutrino mass is fixed to its minimal value. Even without dependence on the sound horizon, our results are in $\approx 3\sigma$ tension with those obtained from the Cepheid-calibrated distance ladder, which begins to cause problems for new physics models that vary $H_0$ by changing acoustic physics or the expansion history immediately prior to recombination.

We investigate the effects of nonzero spatial curvature on cosmic inflation in light of cosmic microwave background (CMB) anisotropy measurements from the Planck Legacy 2018 release and from the 2015 observing season of BICEP2 and the Keck Array. Even a small percentage of nonzero curvature today would significantly limit the total number of $e$-folds of the scale factor during inflation, rendering just-enough inflation scenarios with a kinetically dominated or fast-roll stage prior to slow-roll inflation more likely. Finite inflation leads to oscillations and a cutoff toward large scales in the primordial power spectrum and curvature pushes them into the CMB observable window. Using nested sampling, we carry out Bayesian parameter estimations and model comparisons taking into account constraints from reheating and horizon considerations. We confirm the preference of CMB data for closed universes with Bayesian odds of over $100:1$ and with a posterior on the curvature density parameter of ${\mathrm{\Omega }}_{K,0}=-0.051\pm 0.017$ for a curvature extension of Lambda cold dark matter and ${\mathrm{\Omega }}_{K,0}=-0.031\pm 0.014$ for Starobinsky inflation. Model comparisons of various inflation models give similar results to flat universes with the Starobinsky model outperforming most other models.

We present a new neural network approach for deblending galaxy images in astronomical data using residual dense neural network (RDN) architecture. We train the network on synthetic galaxy images similar to the typical arrangements of field galaxies with a finite point spread function (PSF) and realistic noise levels. The main novelty of our approach is the usage of two distinct neural networks: (i) a deblending network which isolates a single galaxy postage stamp from the composite and, (ii) a classifier network which counts the remaining number of galaxies. The deblending proceeds by iteratively peeling one galaxy at a time from the composite until the image contains no further objects as determined by the classifier, or by other stopping criteria. By looking at the consistency in the outputs of the two networks, we can assess the quality of the deblending. We characterize the flux and shape reconstructions in different quality bins and compare our deblender with the industry standard, sextractor. We also discuss possible future extensions for the project with variable PSFs and noise levels.

The Antarctic Impulse Transient Antenna (ANITA) Collaboration [1–3] has reported two anomalous events with noninverted polarity. These events are hard to explain in terms of conventional cosmic rays (CRs). We explore a new possible explanation for these anomalous events by suggesting that these events can be related to the dark matter (DM) annihilations within the so-called axion quark nugget (AQN) DM model. This model was initially invented for a completely different purpose: to explain the observed similarity between the dark and the visible components in the Universe—i.e., ${\mathrm{\Omega }}_{\mathrm{DM}}\sim {\mathrm{\Omega }}_{\text{visible}}$—without any fitting parameters. We investigate the signal properties of the upward-going AQN events, including the event rate, the pulse duration, and the electric field strength, and find them consistent with the observations. We list several features of the upward-going AQN events distinct from conventional CR air showers. The observations (or nonobservation) of these features may substantiate (or refute) our proposal.

Our basic theoretical understanding of the sources of cosmic rays and their propagation through the interstellar medium is hindered by the Sun, that through the solar wind affects the observed cosmic-ray spectra. This effect is known as solar modulation. Recently released cosmic-ray observations from the Alpha Magnetic Spectrometer (AMS-02) and publicly available measurements of the solar wind properties from the Advanced Composition Explorer and the Wilcox observatory allow us to test the analytical modeling of the time-, charge- and rigidity-dependence of solar modulation. We rely on associating measurements on the local heliospheric magnetic field and the heliospheric current sheet’s tilt angle, to model the time-dependence and amplitude of cosmic-ray solar modulation. We find evidence for the solar modulation’s charge- and rigidity-dependence during the era of solar cycle 24. Our analytic prescription to model solar modulation can explain well the large-scale time evolution of positively charged cosmic-ray fluxes in the range of rigidities from 1 GV to 10 GV. We also find that cosmic-ray electron fluxes measured during the first years of cycle 24 are less trivial to explain, due to the complex and rapidly evolving structure of the heliosphere’s magnetic field that they experienced as they propagated inwards.

We investigate nuclear pasta structures at high temperatures in the framework of a relativistic mean field model with Thomas-Fermi approximation. Typical pasta structures (droplet, rod, slab, tube, and bubble) are obtained, which form various crystalline configurations. The properties of those nuclear pastas are examined in a three-dimensional geometry with reflection symmetry, where the optimum lattice constants are fixed by reproducing the droplet/bubble density that minimizes the free energy adopting spherical or cylindrical approximations for Wigner-Seitz cells. It is found that different crystalline structures can evolve into each other via volume conserving deformations. For fixed densities and temperatures, the differences of the free energies per baryon of nuclear pasta in various shapes and lattice structures are typically on the order of tens of keV, suggesting the possible coexistence of those structures. As temperature increases, the thermodynamic fluctuations are expected to disrupt the long-range ordering in nuclear pasta structures. We then estimate the critical conditions for nuclear pasta to become disordered and behave like liquid, which are found to be sensitive to the densities, temperatures, proton fractions, and nuclear shapes. If we further increase temperature, eventually the nonuniform structures of nuclear pasta become unstable and are converted into uniform nuclear matter. The phase diagrams of nuclear matter are then estimated, which should be useful for understanding the evolutions of neutron stars, supernova dynamics, and binary neutron star mergers.

The Laser Interferometer Space Antenna (LISA), which is currently under construction, is designed to measure gravitational wave signals in the milli-Hertz frequency band. It is expected that tens of millions of Galactic binaries will be the dominant sources of observed gravitational waves. The Galactic binaries producing signals at mHz frequency range emit quasimonochromatic gravitational waves, which will be constantly measured by LISA. To resolve as many Galactic binaries as possible is a central challenge of the upcoming LISA dataset analysis. Although it is estimated that tens of thousands of these overlapping gravitational wave signals are resolvable, and the rest blurs into a galactic foreground noise, extracting tens of thousands of signals using Bayesian approaches is still computationally expensive. We developed a new end-to-end pipeline using Gaussian process regression to model the log-likelihood function in order to rapidly compute Bayesian posterior distributions. Using the pipeline we are able to solve the Lisa Data Challenge (LDC) 1-3 consisting of noisy data as well as additional challenges with overlapping signals and particularly faint signals.

In this article, we have explored the very important quantity of lepton pair production from a hot and dense QCD medium in presence of an arbitrary external magnetic field for simultaneous nonzero values of both the parallel (along the direction of the external field) and perpendicular (lying on the transverse plane to the external field) components of the dilepton momentum. As opposed to the zero magnetic field case (the so-called Born rate) or the lowest Landau level approximated rate, where only the annihilation process contributes, here we observe contributions also arising out of the quark and antiquark decay processes. We found the encouraging result of considerable enhancement of lepton pair production in presence of an arbitrary magnetic field. We decompose the total rate into different physical processes and discuss their behaviors for both zero and nonzero baryon density. The whole analysis is then subjected to an effective model treatment, where we have incorporated the magnetic field induced novel effects of magnetic catalysis (MC) and inverse MC (IMC) through a medium dependent scalar coupling, which leads to some further interesting observations.

We investigate magnetic field $(eB)$ dependence of constituent quark mass, the longitudinal and transverse pressure as well as the magnetization and magnetic susceptibility of strongly interacting quark matter. We employ the two-flavor Polyakov Nambu–Jona-Lasinio model with the inclusion of the anomalous magnetic moment (AMM) of the quarks at finite temperature ($T$) and finite quark chemical potential $({\mu }_q)$ capturing different stages of chiral phase transition. We find that the transverse pressure, magnetization, and magnetic susceptibility become highly oscillatory for large values of $eB$ in the chiral symmetry broken phase. However, the oscillations cease to occur at higher values of $T$ and ${\mu }_q$ when chiral symmetry is (partially) restored and the anisotropic nature of the pressure becomes significant even at smaller values of $eB$. As the inclusion of AMM of the quarks leads to inverse magnetic catalysis of the transition temperature, we observe that the variations of transverse pressure, magnetization, and magnetic susceptibility are significantly modified in the vicinity of the chiral transition temperature. Furthermore, above the chiral transition temperature the magnetic susceptibility is found to remain positive for a wide range of $eB$, indicating a paramagnetic character of the strongly interacting quark matter. Finally, we have also examined the magnetism of strongly interacting matter in the quarkyonic phase. The obtained results could be useful for a magnetohydrodynamic evolution of hot and dense matter created in heavy-ion collisions.

We benefit from a recent lattice determination of the full set of vector, axial and tensor form factors for the ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c^{*}(2595)\tau {\overline{\nu }}_{\tau }$ and ${\mathrm{\Lambda }}_c^{*}(2625)\tau {\overline{\nu }}_{\tau }$ semileptonic decays to study the possible role of these two reactions in lepton flavor universality violation studies. Using an effective theory approach, we analyze different observables that can be accessed through the visible kinematics of the charged particles produced in the tau decay, for which we consider the ${\pi }^{-}{\nu }_{\tau },{\rho }^{-}{\nu }_{\tau }$ and ${\mu }^{-}{\overline{\nu }}_{\mu }{\nu }_{\tau }$ channels. We compare the results obtained in the Standard Model and other schemes containing new physics (NP) interactions, with either left-handed or right-handed neutrino operators. We find a discriminating power between models similar to the one of the ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c$ decay, although somewhat hindered in this case by the larger errors of the ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c^{*}$ lattice form factors. Notwithstanding this, the analysis of these reactions is already able to discriminate between some of the NP scenarios and its potentiality will certainly improve when more precise form factors are available.

We present the implications of the recent measurement of $W$ boson at CDF II on the two-Higgs-doublet model (2HDM). In the analysis, we impose theoretical bounds such as vacuum stability and perturbative unitarity, and several experimental constraints. In addition, we take into account the measurement of ${\sin }^2{\theta }_W(m_Z{)}_{\overline{\mathrm{MS}}}$ on top of the CDF $W$-boson mass to investigate how the $S$ and $T$ parameters are determined. We explore two possible scenarios depending on whether the Higgs boson observed at the LHC is the lighter or heavier of $CP$-even neutral Higgs bosons for 2HDM type I and II. Using the results, we show how the parameter space is constrained, and compare it with the one based on the PDG average of $m_W$. Furthermore, we explore phenomenological consequences of electroweak precision observables that can be affected by $m_W$ within the predictions of the 2HDM, and the reduction in parameter space expected from future measurements at the Future Circular Lepton Collider.

We establish new experiments to search for dark matter based on a model of a light scalar field with a dilaton-like coupling to the electromagnetic field, which is strongly motivated by superstring theory. We estimate the power of the photon signal in the process of a nonresonant scalar-photon transition and in a cavity resonator permeated by electric and magnetic fields. We show that existing cavity resonators employed in experiments like ADMX have a low but nonvanishing sensitivity to the scalar-photon coupling. As a result, by repurposing the results of the ADMX experiment, we find new limits on the scalar-photon coupling in the range of the scalar field masses from 2.7 to $4.2\mu \mathrm{eV}$. We discuss possible modifications of this experiment, which enhance the sensitivity to the scalar field dark matter. We also propose a broadband experiment for scalar field dark matter searches based on a high-voltage capacitor. The estimated sensitivity of this experiment exceeds that of the experiment based on molecular spectroscopy by nearly 2 orders of magnitude.

We propose the use of FASER as a light-shining-through-walls experiment to search for axions and axionlike particles (ALPs). LHC collisions generate a high intensity and high energy photon flux in the forward direction which can oscillate into ALPs in the magnetic fields that are used to confine the beam. These $\text{ALPs}$ then pass through about 100 m of rock before reaching the magnetic fields of FASER, where they can convert back into photons and be detected by an electromagnetic calorimeter. In the next years, FASER and its successor FASER2 at the Forward Physics Facility will be able to explore regions of the ALP parameter space inaccessible by other laboratory-based experiments.

The CDF II experiment has recently determined the mass of the $W$ boson to be $m_W(\mathrm{CDF}\mathrm{II})=80.4335\pm 0.0094\mathrm{GeV}$, which deviates from the standard model prediction at $7\sigma$ level. Although this new result is in tension with other experiments such as those at LHC and LEP, it is worth discussing possible implications on new physics by this anomaly. We show that this large discrepancy can be explained by nonaligned vacuum expectation values of isospin triplet scalar fields in the Georgi-Machacek model extended with custodial symmetry-breaking terms in the potential. The latter is required to avoid an undesirable Nambu-Goldstone boson as well as to be the consistent treatment of radiative corrections. With $m_W(\mathrm{CDF}\mathrm{II})$ as one of the renormalization inputs at the one-loop level, we derive the required difference in the triplet vacuum expectation values, followed by a discussion of phenomenological consequences in the scenario.

In this paper, axion models supplemented by leptoquarks and diquarks are systematically analyzed. Turning on some couplings to and among these latter states permits us to unify the Peccei-Quinn symmetry with baryon ($\mathcal{B}$) and lepton ($\mathcal{L}$) numbers, such that the axion becomes associated to the spontaneous breaking of the three $U(1)$ symmetries. All possible four- and six-fermion patterns of $\mathcal{B}$ and $\mathcal{L}$ violation are discussed, including those inducing proton decay, with $\mathrm{\Delta }\mathcal{B}=1$ and $\mathrm{\Delta }\mathcal{L}=\pm 1,\pm 3$, neutron-antineutron oscillations with $\mathrm{\Delta }\mathcal{B}=2$, and Majorana neutrino masses with $\mathrm{\Delta }\mathcal{L}=2$. Scenarios in which one or two axion fields necessarily appear in any $\mathcal{B}$ and/or $\mathcal{L}$ violating operators are also constructed. Nucleon decays would then necessarily involve an axion in the final state, while neutron-antineutron oscillations would only happen in an axionic background. This could have implications for the neutron lifetime puzzle, and more generally, opens the door to new phenomenological and cosmological applications.