Vector boson stars, or Proca stars, have been recently obtained as fully nonlinear numerical solutions of the Einstein-(complex)-Proca system [1]. These are self-gravitating, everywhere nonsingular, horizonless Bose-Einstein condensates of a massive vector field, which resemble in many ways, but not all, their scalar cousins, the well-known (scalar) boson stars. In this paper we report fully nonlinear numerical evolutions of Proca stars, focusing on the spherically symmetric case, with the goal of assessing their stability and the end point of the evolution of the unstable stars. Previous results from linear perturbation theory indicate that the separation between stable and unstable configurations occurs at the solution with maximal ADM mass. Our simulations confirm this result. Evolving numerically unstable solutions, we find, depending on the sign of the binding energy of the solution and on the perturbation, three different outcomes: (i) migration to the stable branch, (ii) total dispersion of the scalar field, or (iii) collapse to a Schwarzschild black hole. In the latter case, a long-lived Proca field remnant—a Proca wig—composed by quasibound states, may be seen outside the horizon after its formation, with a lifetime that scales inversely with the Proca mass. We comment on the similarities/differences with the scalar case as well as with neutron stars.

We present new stable solutions of the Tolman-Oppenheimer-Volkoff equations for quark stars using a quark matter equation of state based on the SU(3) quark-meson model that exhibits the onset of the chiral phase transition. These new solutions appear as two stable branches in the mass-radius relation allowing for so-called twin stars, i.e., two stable quark star solutions with the same mass, but distinctly different radii. We find solutions which are compatible with causality, the stability conditions of dense matter, the astrophysical constraints of the rotation of the millisecond pulsar PSR J1748-2446ad and the $2M_{\odot }$ pulsar mass constraint.

We demonstrate the existence of various nonlinear waves along open vortex filaments in the nonrelativistic Abelian Higgs model. These include nonlinear waves, which give the birth and death of helical filaments, as well breathers, which modify the amplitude of helical filaments periodically in time. Importantly, we demonstrate that some of the dynamics are quite particular to the equation of motion for vortex filaments under the nonrelativistic Abelian Higgs model, giving rise to vortex filament solutions not possible under the hydrodynamic vortex filament equation of motion (the local induction approximation) or generalizations used to study the dynamics of quantized vortex filaments in ${\mathrm{He}}^4$.

We show that in a complementary two-Higgs doublet model (C2HDM) the $CP$ violating phase in the Cabibbo-Kobayashi-Maskawa matrix can be generated spontaneously, dangerous flavor changing neutral currents (FCNC) can be naturally suppressed and the strong $CP$ problem can also be avoided. The two Higgs doublets in the model are complementary in the sense that none of them is enough to describe masses of a given type of quarks. We find that the strength of FCNC is suppressed by the strength of Yukawa couplings of the first generation quark and the tree-level FCNC is sufficiently small. Using an explicit example, we show that radiative correction to the assumed Yukawa couplings can modify the discussion about the strong $\theta$. The correction to the strong $\theta$ is estimated to be less than around ${10}^{-12}\sim {10}^{-10}$ which can be tested in future experiments.

Given the disappearance of the 750 GeV diphoton LHC signal and the absence of signals at high mass in this and other channels, significant constraints on the mixed Higgs-radion of the five-dimensional Randall-Sundrum model arise. By combining all channels, these constraints place a significant radion-mass-dependent lower bound on the radion vacuum expectation value that is fairly independent of the amount of Higgs radion mixing.

The unpolarized, helicity and transversity parton distribution functions of the nucleon are studied within a convolution model where the bare nucleon is dressed by its virtual meson cloud. Using light-front time-ordered perturbation theory, the Fock states of the physical nucleon are expanded in a series involving a bare nucleon and two-particle (meson-baryon) states. The bare baryons and mesons are described with light-front wave functions (LFWFs) for the corresponding valence-parton components. Using a representation in terms of overlap of LFWFs, the role of the nonperturbative antiquark degrees of freedom and the valence-quark contribution at the input scale of the model is discussed for the leading-twist collinear parton distributions. After introducing perturbative QCD effects through evolution to experimental scales, the results are compared with available data and phenomenological extractions. Predictions for the nucleon tensor charge are also presented, finding a very good agreement with recent phenomenological extractions.

We study the existence of $Z(3)$ metastable states in the presence of the dynamical quarks within the ambit of a Polyakov quark meson (PQM) model. Within the parameters of the model, it is seen that for temperatures ${\mathrm{T}}_m$ greater than the chiral transition temperature ${\mathrm{T}}_c$, $Z(3)$ metastable states exist (${\mathrm{T}}_m\sim 310\mathrm{MeV}$ at zero chemical potential). At finite chemical potential ${\mathrm{T}}_m$ is larger than the same at vanishing chemical potential. We also observe a shift of ($\sim 5°$) in the phase of the metastable vacua at zero chemical potential. The energy density difference between true and $Z(3)$ metastable vacua is very large in this model. This indicates a strong explicit symmetry-breaking effect due to quarks in the PQM model. We compare this explicit symmetry breaking in the PQM model with small explicit symmetry breaking as a linear term in a Polyakov loop added to the Polyakov loop potential. We also study the possibility of domain growth in a quenched transition to quark gluon plasma in relativistic heavy ion collisions.

We investigate the potential of inclusive-jet production in deep-inelastic scattering (DIS) at a future electron-ion collider (EIC) to improve our current knowledge of nuclear parton density functions (PDFs). We demonstrate that the kinematic reach is extended similarly to inclusive DIS, but that the uncertainty of the nuclear PDFs, in particular of the gluon density at low Bjorken-$x$, is considerably reduced, by up to an order of magnitude compared to the present situation. Using an approximate next-to-next-to-leading order (aNNLO) calculation implemented in the program JetViP, we also make predictions for three different EIC designs and for four different light and heavy nuclei.

We report the first measurement of the $T$-odd moments in the decay $D^0\to K_S^0{\pi }^{+}{\pi }^{-}{\pi }^0$ from a data sample corresponding to an integrated luminosity of $966{\mathrm{fb}}^{-1}$ collected by the Belle experiment at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. From these moments we determine the $CP$-violation-sensitive asymmetry $a_{CP}^{T\text{-odd}}=[-0.28\pm 1.38(\mathrm{stat}.{)}_{-0.76}^{+0.23}(\mathrm{syst}.)]\times {10}^{-3}$, which is consistent with no $CP$ violation. In addition, we perform $a_{CP}^{T\text{−}\mathrm{odd}}$ measurements in different regions of the $D^0\to K_S^0{\pi }^{+}{\pi }^{-}{\pi }^0$ phase space; these are also consistent with no $CP$ violation.

Screened modified gravity (SMG) is a kind of scalar-tensor theory with screening mechanisms, which can suppress the fifth force in dense regions and allow theories to evade the solar system and laboratory tests. In this paper, we investigate how the screening mechanisms in SMG affect the gravitational radiation damping effects, calculate in detail the rate of the energy loss due to the emission of tensor and scalar gravitational radiations, and derive their contributions to the change in the orbital period of the binary system. We find that the scalar radiation depends on the screened parameters and the propagation speed of scalar waves, and the scalar dipole radiation dominates the orbital decay of the binary system. For strongly self-gravitating bodies, all effects of scalar sector are strongly suppressed by the screening mechanisms in SMG. By comparing our results to observations of binary system PSR $\mathrm{J}1738+0333$, we place the stringent constraints on the screening mechanisms in SMG. As an application of these results, we focus on three specific models of SMG (chameleon, symmetron, and dilaton), and derive the constraints on the model parameters, respectively.

The direct discovery of gravitational waves from compact binary systems leads for the first time to explore the possibility of black hole spectroscopy. Newly formed black holes produced by coalescing events are copious emitters of gravitational radiation, in the form of damped sinusoids, the quasinormal modes. The latter provides a precious source of information on the nature of gravity in the strong field regime, as they represent a powerful tool to investigate the validity of the no-hair theorem. In this work we perform a systematic study on the accuracy with which current and future interferometers will measure the fundamental parameters of ringdown events, such as frequencies and damping times. We analyze how these errors affect the estimate of the mass and the angular momentum of the final black hole, constraining the parameter space which will lead to the most precise measurements. We explore both single and multimode events, showing how the uncertainties evolve when multiple detectors are available. We also prove that, for the second generation of interferometers, a network of instruments is a crucial and necessary ingredient to perform strong-gravity tests of the no-hair theorem. Finally, we analyze the constraints that a third generation of detectors may be able to set on the mode’s parameters, comparing the projected bounds against those obtained for current facilities.

A classical solution for electromagnetic monopoles induced by gravitational (global) monopoles in the presence of a (four-dimensional) Kalb-Ramond axion field is found. The magnetic charge of such a solution is induced by a nonzero Kalb-Ramond field strength, prevalent in string theory. Bounds from the current run of the LHC experiments are used to constrain the parameters of the model. Because the production mechanism depends on the details of the model and its ultraviolet completion, such bounds, presently, are only indicative.

The B-modes of polarization at frequencies ranging from 50–1000 GHz are produced by Galactic dust, lensing of primordial E-modes in the cosmic microwave background (CMB) by intervening large scale structure, and possibly by primordial B-modes in the CMB imprinted by gravitational waves produced during inflation. The conventional method used to separate the dust component of the signal is to assume that the signal at high frequencies (e.g. 350 GHz) is due solely to dust and then extrapolate the signal down to a lower frequency (e.g. 150 GHz) using the measured scaling of the polarized dust signal amplitude with frequency. For typical Galactic thermal dust temperatures of $\sim 20\mathrm{K}$, these frequencies are not fully in the Rayleigh-Jeans limit. Therefore, deviations in the dust cloud temperatures from cloud to cloud will lead to different scaling factors for clouds of different temperatures. Hence, when multiple clouds of different temperatures and polarization angles contribute to the integrated line-of-sight polarization signal, the relative contribution of individual clouds to the integrated signal can change between frequencies. This can cause the integrated signal to be decorrelated in both amplitude and direction when extrapolating in frequency. Here we carry out a Monte Carlo analysis on the impact of this line-of-sight extrapolation noise on a greybody dust model consistent with Planck and Pan-STARRS observations, enabling us to quantify its effect. Using results from the Planck experiment, we find that this effect is small, more than an order of magnitude smaller than the current uncertainties. However, line-of-sight extrapolation noise may be a significant source of uncertainty in future low-noise primordial B-mode experiments. Scaling from Planck results, we find that accounting for this uncertainty becomes potentially important when experiments are sensitive to primordial B-mode signals with amplitude $r\lesssim 0.0015$ in the greybody dust models considered in this paper.

Milky Way–like galaxies are predicted to host a very large number of dark matter subhalos. Some massive and nearby subhalos could generate detectable gamma rays, appearing as unidentified, spatially extended and stable gamma-ray sources. We search for such sources in the third Fermi Large Area Telescope source list (3FGL) and report the identification of a new candidate, 3FGL J1924.8-1034. With the Fermi-LAT Pass 8 data, we find that 3FGL J1924.8-1034 is spatially extended at a high confidence level of $5.4\sigma$, with a best-fit extension radius of $\sim 0.15°$. No significant variability has been found and its gamma-ray spectrum is well fitted by the dark matter annihilation into $b\overline{b}$ with a mass of $\sim 43\mathrm{GeV}$. All these facts make 3FGL J1924.8-1034 a possible dark matter subhalo candidate. However, due to the limited angular resolution, the possibility of that the spatial extension of 3FGL J1924.8-1034 is caused by the contamination from the other unresolved point source cannot be ruled out.

We study the decay of 125 GeV Higgs boson to a pair of lightest neutralinos in the phenomenological minimal supersymmetric standard model in the context of collider searches and astrophysical experiments. We consider the parameter space for light neutralinos that can be probed via the invisible Higgs decays and Higgsino searches at the ILC. We consider the cases where the light neutralino is compatible with the observed relic density or where the thermal relic is overabundant, pointing to nonstandard cosmology. In the former case, when the neutralino properties give rise to underabundant relic density, the correct amount of relic abundance is assumed to be guaranteed by either additional dark matter particles or by nonthermal cosmology. We contrast these different cases. We assess what astrophysical measurements can be made, in addition to the measurements made at the ILC, which can provide a clue to the nature of the light neutralino. We find that a number of experiments, including Xenon-nT, PICO-250, and LZ, in conjunction with measurements made at the ILC on invisible Higgs width can pin down the nature of this neutralino, along with its cosmological implications. Additionally, we also point out potential LHC signatures that could be complementary in this region of parameter space.

In this paper, we discuss dark matter candidates in a visible heavy QCD axion model. There, a mirror copied sector of the Standard Model with mass scales larger than the Standard Model is introduced. By larger mass scales of the mirrored sector, the QCD axion is made heavy via the axial anomaly in the mirrored sector without spoiling the Peccei-Quinn mechanism to solve the strong $CP$ problem. Since the mirror copied sector possesses the same symmetry structure with the Standard Model sector, the model predicts multiple stable particles. As we will show, the mirrored charged pion and the mirrored electron can be viable candidates for dark matter. They serve as self-interacting dark matter with a long-range force. We also show that the mirrored neutron can be lighter than the mirrored proton in a certain parameter region. There, the mirrored neutron can also be a viable dark matter candidate when its mass is around 100 TeV. It is also shown that the mirrored neutrino can also be a viable candidate for dark matter.

The right-handed neutrinos within the type-I seesaw mechanism can induce large radiative corrections to the Higgs mass, and naturalness arguments can then be used to set limits on their mass scale and Yukawa couplings. Driven by minimality, we consider the presence of two degenerate right-handed neutrinos. We compare the limits from naturalness with the ones from the stability of the electroweak vacuum and from lepton flavor violation. Implications from neutrinoless double beta decay are also discussed and renormalization effects for the light neutrino parameters are presented. Adding small perturbations to the degenerate heavy neutrino spectrum allows for successful leptogenesis.

There are presently several discrepancies in $b\to s{\ell }^{+}{\ell }^{-}$ decays of $B$ mesons suggesting new physics coupling to $b$ quarks and leptons. We show that a $Z^{\prime }$, with couplings to quarks and muons that can explain the $B$-decay anomalies, can also couple to dark matter in a way that is consistent with its relic abundance, direct detection limits, and hints of indirect detection. The latter include possible excess events in antiproton spectra recently observed by the AMS-02 experiment. We present two models, having a heavy (light) $Z^{\prime }$ with $m_{Z^{\prime }}\sim 600(12)\mathrm{GeV}$ and fermionic dark matter with mass $m_{\chi }\sim 50(2000)\mathrm{GeV}$, producing excess antiprotons with energies of $\sim 10(300)\mathrm{GeV}$. The first model is also compatible with fits for the Galactic center GeV gamma-ray excess.

We investigate the form factors of $B_c$ meson into $S$-wave charmonium within the nonrelativistic QCD effective theory and obtain the next-to-leading order relativistic corrections to the form factors, where both the $B_c$ meson and the charmonium are treated as the nonrelativistic bound states. Treating the charm quark as a light quark in the limit $m_c/m_b\to 0$, some form factors are identical at the maximum recoil point, which are consistent with the predictions in the heavy-quark effective theory and the large-energy effective theory. Considering that the branching ratios of $B_c^{+}\to J/\psi D_s^{+}$ and $B_c^{+}\to J/\psi D_s^{*+}$ have been measured by the LHCb and ATLAS Collaborations recently, we employ the form factors of $B_c$ meson into $S$-wave charmonium at the next-to-leading order accuracy to these two decay channels and obtain more precise predictions of their decay rates. Numerical results indicate that the factorizable diagrams dominate the contribution in these two channels, while the color-suppressed and the annihilation diagrams contribute less than 10 percent. Our results are consistent with the LHCb and ATLAS data.