Imaging surveys of galaxies will have a high number density and angular resolution yet a poor redshift precision. Intensity maps of neutral hydrogen will have accurate redshift resolution yet will not resolve individual sources. Using this complementarity, we show how the clustering redshifts approach proposed for spectroscopic surveys can also be used in combination with intensity mapping observations to calibrate the redshift distribution of galaxies in an imaging survey and, as a result, reduce uncertainties in photometric-redshift measurements. We show how the intensity mapping surveys to be carried out with the MeerKAT, HIRAX and SKA instruments can improve photometric-redshift uncertainties to well below the requirements of DES and LSST. The effectiveness of this method as a function of instrumental parameters, foreground subtraction and other potential systematic errors is discussed in detail.

The nonlinear transport features of inhomogeneous chiral plasma in the presence of electromagnetic fields, in rotating coordinates are studied within the relaxation time approach. The chiral distribution functions up to second order in the electric field in rotating coordinates and the derivatives of chemical potentials are established by solving the Boltzmann transport equation. First, the vector and axial current densities in the weakly ionized chiral plasma for vanishing magnetic field are calculated. They involve the rotational analogues of the Hall effect as well as several new terms arising from the Coriolis and fictitious centrifugal forces. Then in the short relaxation time regime the angular velocity and electromagnetic fields are treated as perturbations. The current densities are obtained by retaining the terms up to second order in perturbations. The time evolution equations of the inhomogeneous chemical potentials are derived by demanding that collisions conserve the particle number densities.

We compute the power spectrum at one-loop order in standard perturbation theory for the matter density field to which a standard Lagrangian baryonic acoustic oscillation (BAO) reconstruction technique is applied. The BAO reconstruction method corrects the bulk motion associated with the gravitational evolution using the inverse Zel’dovich approximation (ZA) for the smoothed density field. We find that the overall amplitude of one-loop contributions in the matter power spectrum substantially decreases after reconstruction. The reconstructed power spectrum thereby approaches the initial linear spectrum when the smoothed density field is close enough to linear, i.e., the smoothing scale $R_s\gtrsim 10h^{-1}\mathrm{Mpc}$. On smaller $R_s$, however, the deviation from the linear spectrum becomes significant on large scales ($k\lesssim R_s^{-1}$) due to the nonlinearity in the smoothed density field, and the reconstruction is inaccurate. Compared with N-body simulations, we show that the reconstructed power spectrum at one-loop order agrees with simulations better than the unreconstructed power spectrum. We also calculate the tree-level bispectrum in standard perturbation theory to investigate non-Gaussianity in the reconstructed matter density field. We show that the amplitude of the bispectrum significantly decreases for small $k$ after reconstruction and that the tree-level bispectrum agrees well with N-body results in the weakly nonlinear regime.

Recent studies of radio data put strong constraints on annihilation cross sections for dark matter. In this article, we provide the first analysis of using M33 radio data in constraining annihilating dark matter. The resulting constraints of annihilation cross sections for some channels are more stringent than that obtained from six years of Fermi Large Area Telescope (Fermi-LAT) gamma-ray observations of the Milky Way dwarf spheroidal satellite galaxies. In particular, the conservative lower limits of dark matter mass annihilating via $e^{+}{e}^{-}$, ${\mu }^{+}{\mu }^{-}$ and ${\tau }^{+}{\tau }^{-}$ channels are 190, 120 and 70 GeV, respectively, with the thermal relic annihilation cross section. These results are in significant tension with some of the recent quantitative analyses of the AMS-02 and Fermi-LAT data of the Milky Way center.

The small quark mixing, described by the Cabibbo-Kobayashi-Maskawa (CKM) matrix in the standard model, may be a clue to reveal new physics around the TeV scale. We consider a simple scenario that extra particles in a hidden sector radiatively mediate the flavor violation to the quark sector around the TeV scale and effectively realize the observed CKM matrix. The lightest particle in the hidden sector, whose contribution to the CKM matrix is expected to be dominant, is a good dark matter (DM) candidate. There are many possible setups to describe this scenario, so that we investigate some universal predictions of this kind of model, focusing on the contribution of DM to the quark mixing and flavor physics. In this scenario, there is an explicit relation between the CKM matrix and flavor violating couplings, such as four-quark couplings, because both are radiatively induced by the particles in the hidden sector. Then, we can explicitly find the DM mass region and the size of Yukawa couplings between the DM and quarks, based on the study of flavor physics and DM physics. In conclusion, we show that DM mass in our scenario is around the TeV scale, and the Yukawa couplings are between $\mathcal{O}(0.01)$ and $\mathcal{O}(1)$. The spin-independent DM scattering cross section is estimated as $\mathcal{O}({10}^{-9})$ [pb]. An extra colored particle is also predicted at the $\mathcal{O}(10)\mathrm{TeV}$ scale.

We consider a dark matter (DM) model that arises from the interplay of two renormalizable dark matter models, namely, the doublet-triplet fermion model and the doublet-triplet scalar model. Despite being excellent exponents of the weakly interacting massive particle paradigm, the physics related to DM in each of these models fails at the same time to account for neutrino masses. It turns out that from the combination of these two models it is possible to generate neutrino masses at one-loop level in the four topologies that are realizations of the Weinberg operator for neutrino masses at one loop. In this work, we combine both models focusing mostly on fermionic dark matter lying at the electroweak scale. We analyze the impact of the extra charged fields on the Higgs diphoton decay and find that, thanks to the presence of the charged scalars, it is possible to have a viable DM region at the electroweak scale.

We propose a minimal extension of the standard model by including a scalar triplet with hypercharge 2 and two vectorlike leptons, one doublet and a singlet, to explain simultaneously the nonzero neutrino mass and dark matter (DM) content of the Universe. The DM emerges as a mixture of the neutral component of the vectorlike lepton doublet and singlet, being odd under a discrete $Z_2$ symmetry. After electroweak symmetry breaking the triplet scalar gets an induced vacuum expectation value, which gives Majorana masses not only to the light neutrinos but also to the DM. Because of the Majorana mass of DM, the $Z$ mediated elastic scattering with nucleon is forbidden. However, the Higgs boson mediated direct detection cross section of the DM gives an excellent opportunity to probe it at Xenon1T. The DM cannot be detected at the collider. However, the charged partner of the DM (often next-to-lightest stable particle) can give large displaced vertex signature at the Large Hadron Collider.

I present approximate results that include third-order soft-gluon corrections for the associated production of a single top quark with a $W$ boson. The calculation uses expressions from soft-gluon resummation at next-to-next-to-leading-logarithm (NNLL) accuracy. From the NNLL resummed cross section, I derive approximate next-to-next-to-next-to-leading-order ($\mathrm{a}{\mathrm{N}}^3\mathrm{LO}$) cross sections for the process $bg\to t{W}^{-}$ at LHC and Tevatron energies. The $\mathrm{a}{\mathrm{N}}^3\mathrm{LO}$ top-quark transverse-momentum and rapidity distributions in $tW$ production are also presented.

Stimulated by the BESIII observation of $X(2100)$, $X(2500)$, and $\eta (2225)$, we try to pin down new pseudoscalar meson nonets including these states. The analysis of mass spectra and the study of strong decays indicate that $X(2120)$ and $\eta (2225)$ associated with $\pi (2070)$ and the predicted kaon $K(2150)$ may form a new pseudoscalar meson nonet. In addition, more experimental data for $X(2100)$ are necessary to determine its structure of nonets. Then, $X(2500)$, $X(2370)$, $\pi (2360)$, and the predicted kaon $K(2414)$ can be grouped into another new nonet. These assignments to the discussed pseudoscalar states can be further tested in experiment.

Alternative scenarios to the big bang singularity have been subject of intense research for several decades by now. Most popular in this sense have been frameworks were such singularity is replaced by a bounce around some minimal cosmological volume or by some early quantum phase. This latter scenario was devised a long time ago and referred as an “emergent universe” (in the sense that our universe emerged from a constant volume quantum phase). We show here that within an improved framework of canonical quantum gravity (the so-called quantum reduced loop gravity) the Friedmann equations for cosmology are modified in such a way to replace the big bang singularity with a short bounce preceded by a metastable quantum phase in which the volume of the universe oscillates between a series of local maxima and minima. We call this hybrid scenario an “emergent-bouncing universe” since after a pure oscillating quantum phase the classical Friedmann spacetime emerges. Perspective developments and possible tests of this scenario are discussed in the end.

Inspired by the recent “$\text{complexity}=\text{action}$” conjecture, we use the approach proposed by Lehner et al. to calculate the rate of the action of the Wheeler-DeWitt patch at late times for static uncharged and charged black holes in $f(R)$ gravity. Our results have the same expressions in terms of the mass, charge, and electrical potentials at the horizons of black holes as in Einstein’s gravity. In the context of $f(R)$ gravity, the Lloyd bound is saturated for uncharged black holes but violated for charged black holes near extremality. For charged black holes far away from the ground states, the Lloyd bound is violated in four dimensions but satisfied in higher dimensions.

We canonically quantize $O(D+2)$ nonlinear sigma models (NLSMs) with a theta term on arbitrary smooth, closed, connected, oriented $D$-dimensional spatial manifolds $\mathcal{M}$, with the goal of proving the suitability of these models for describing symmetry-protected topological (SPT) phases of bosons in $D$ spatial dimensions. We show that in the disordered phase of the NLSM, and when the coefficient $\theta$ of the theta term is an integer multiple of $2\pi$, the theory on $\mathcal{M}$ has a unique ground state and a finite energy gap to all excitations. We also construct the ground state wave functional of the NLSM in this parameter regime, and we show that it is independent of the metric on $\mathcal{M}$ and given by the exponential of a Wess-Zumino term for the NLSM field, in agreement with previous results on flat space. Our results show that the NLSM in the disordered phase and at $\theta =2\pi k$, $k\in \mathbb{Z}$, has a symmetry-preserving ground state but no topological order (i.e., no topology-dependent ground state degeneracy), making it an ideal model for describing SPT phases of bosons. Thus, our work places previous results on SPT phases derived using NLSMs on solid theoretical ground. To canonically quantize the NLSM on $\mathcal{M}$, we use Dirac’s method for the quantization of systems with second class constraints, suitably modified to account for the curvature of space. In a series of four Appendixes, we provide the technical background needed to follow the discussion in the main sections of the paper.

We carry out a theoretical investigation on the collective dynamics of an ensemble of correlated atoms, subject to both vacuum fluctuations of spacetime and stochastic gravitational waves. A general approach is taken with the derivation of a quantum master equation capable of describing arbitrary confined nonrelativistic matter systems in an open quantum gravitational environment. It enables us to relate the spectral function for gravitational waves and the distribution function for quantum gravitational fluctuations and to indeed introduce a new spectral function for the zero-point fluctuations of spacetime. The formulation is applied to two-level identical bosonic atoms in an off-resonant high-$Q$ cavity that effectively inhibits undesirable electromagnetic delays, leading to a gravitational transition mechanism through certain quadrupole moment operators. The overall relaxation rate before reaching equilibrium is found to generally scale collectively with the number $N$ of atoms. However, we are also able to identify certain states of which the decay and excitation rates with stochastic gravitational waves and vacuum spacetime fluctuations amplify more significantly with a factor of $N^2$. Using such favorable states as a means of measuring both conventional stochastic gravitational waves and novel zero-point spacetime fluctuations, we determine the theoretical lower bounds for the respective spectral functions. Finally, we discuss the implications of our findings on future observations of gravitational waves of a wider spectral window than currently accessible. Especially, the possible sensing of the zero-point fluctuations of spacetime could provide an opportunity to generate initial evidence and further guidance of quantum gravity.

We investigate Proca star (PS) solutions, namely boson star (BS) type solutions for a complex vector field with mass and nonminimal coupling to the Einstein tensor. Irrespective of the existence of nonminimal coupling, PS solutions are mini-BS type, but the inclusion of it changes properties. For positive nonminimal coupling parameters, PS solutions do not exist for central amplitudes above some certain value due to the singular behavior of the evolution equations. For negative nonminimal coupling parameters, there is no such singular behavior, but sufficiently enhanced numerical resolutions are requested for larger amplitudes. Irrespective of the sign of the nonzero nonminimal coupling parameter, PSs with the maximal Arnowitt-Deser-Misner mass and Noether charge are gravitationally bound. Properties of PSs are very similar to those of BSs in scalar-tensor theories including healthy higher-derivative terms.

Ultraviolet completion of the standard model plus gravity at and beyond the Planck scale is a daunting problem to which no generally accepted solution exists. Principal obstacles include (a) lack of data at the Planck scale, (b) the nonrenormalizability of gravity, and (c) the unitarity problem. Here we make a simple observation that, if one treats all Planck scale operators of equal canonical dimension democratically, one can tame some of the undesirable features of these models. With a reasonable amount of fine tuning one can satisfy the slow roll conditions required in viable inflationary models. That remains true even when the number of such operators becomes very large.

Our ignorance of the period between the end of inflation and the beginning of big bang nucleosynthesis limits our understanding of the origins and evolution of dark matter. One possibility is that the Universe’s energy density was dominated by a fast-rolling scalar field while the radiation bath was hot enough to thermally produce dark matter. We investigate the evolution of the dark matter density and derive analytic expressions for the dark matter relic abundance generated during such a period of kination. Kination scenarios in which dark matter does not reach thermal equilibrium require $⟨\sigma v⟩<2.7\times {10}^{-38}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$ to generate the observed dark matter density while allowing the Universe to become radiation dominated by a temperature of 3 MeV. Kination scenarios in which dark matter does reach thermal equilibrium require $⟨\sigma v⟩>3\times {10}^{-26}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$ in order to generate the observed dark matter abundance. We use observations of dwarf spheroidal galaxies by the Fermi Gamma-Ray Telescope and observations of the Galactic Center by the High Energy Stereoscopic System to constrain these kination scenarios. Combining the unitarity constraint on $⟨\sigma v⟩$ with these observational constraints sets a lower limit on the temperature at which the Universe can become radiation dominated following a period of kination if $⟨\sigma v⟩>3\times {10}^{-31}{\mathrm{cm}}^3{\mathrm{s}}^{-1}$. This lower limit is between 0.05 and 1 GeV, depending on the dark matter annihilation channel.

We study the correlations between parameters characterizing neutrino physics and the evolution of dark energy. Using a fluid approach, we show that time-varying dark energy models exhibit degeneracies with the cosmic neutrino background over extended periods of the cosmic history, leading to a degraded estimation of the total mass and number of species of neutrinos. We investigate how to break degeneracies and combine multiple probes across cosmic time to anchor the behavior of the two components. We use Planck cosmic microwave background data and baryonic acoustic oscillation measurements from the BOSS, SDSS, and 6dF surveys to present current limits on the model parameters, and then forecast the future reach from the CMB Stage-4 and DESI experiments. We show that a multiprobe analysis of current data provides only marginal improvement on the determination of the individual parameters and no reduction of the correlations. Future observations will better distinguish the neutrino mass and preserve the current sensitivity to the number of species even in case of a time-varying dark energy component.

We study rapidly rotating hybrid stars with the Dyson-Schwinger model for quark matter and the Brueckner-Hartree-Fock many-body theory with realistic two-body and three-body forces for nuclear matter. We determine the maximum gravitational mass, equatorial radius, and rotation frequency of stable stellar configurations by considering the constraints of the Keplerian limit and the secular axisymmetric instability, and compare with observational data. We also discuss the rotational evolution for constant baryonic mass and find a spin-up phenomenon for supramassive stars before they collapse to black holes.

After the breakthrough from the satellite-borne PAMELA detector, the flux of cosmic-ray (CR) antiprotons has been provided with unprecedented accuracy by AMS-02 on the International Space Station. Its data spans an energy range from below 1 GeV up to 400 GeV and most of the data points contain errors below the amazing level of 5%. The bulk of the antiproton flux is expected to be produced by the scatterings of CR protons and helium off interstellar hydrogen and helium atoms at rest. The modeling of these interactions, which requires the relevant production cross sections, induces an uncertainty in the determination of the antiproton source term that can even exceed the uncertainties in the CR $\overline{p}$ data itself. The aim of the present analysis is to determine the uncertainty required for $p+p\to \overline{p}+X$ cross section measurements such that the induced uncertainties on the $\overline{p}$ flux are at the same level. Our results are discussed both in the center-of-mass reference frame, suitable for collider experiments, and in the laboratory frame, as occurring in the Galaxy. We find that cross section data should be collected with accuracy better than few percent with proton beams from 10 GeV to 6 TeV and a pseudorapidity $\eta$ ranging from 2 to almost 8 or, alternatively, with $p_{\mathrm{T}}$ from 0.04 to 2 GeV and $x_{\mathrm{R}}$ from 0.02 to 0.7. Similar considerations hold for the $p\mathrm{He}$ production channel. The present collection of data is far from these requirements. Nevertheless, they could, in principle, be reached by fixed target experiments with beam energies in the reach of CERN accelerators.

We perform magnetohydrodynamic simulations in full general relativity of uniformly rotating stars that are marginally unstable to collapse. These simulations model the direct collapse of supermassive stars (SMSs) to seed black holes that can grow to become the supermassive black holes at the centers of quasars and active galactic nuclei. They also crudely model the collapse of massive Population III stars to black holes, which could power a fraction of distant, long gamma-ray bursts. The initial stellar models we adopt are $\mathrm{\Gamma }=4/3$ polytropes initially with a dynamically unimportant dipole magnetic field. We treat initial magnetic-field configurations either confined to the stellar interior or extending out from the stellar interior into the exterior. We find that the black hole formed following collapse has mass $M_{\mathrm{BH}}\simeq 0.9M$ (where $M$ is the mass of the initial star) and dimensionless spin parameter $a_{\mathrm{BH}}/M_{\mathrm{BH}}\simeq 0.7$. A massive, hot, magnetized torus surrounds the remnant black hole. At $\mathrm{\Delta }t\sim 400–550M\approx 2000-2700(M/{10}^6{M}_{\odot })\mathrm{s}$ following the gravitational wave peak amplitude, an incipient jet is launched. The disk lifetime is $\mathrm{\Delta }t\sim {10}^5(M/{10}^6{M}_{\odot })\mathrm{s}$, and the outgoing Poynting luminosity is $L_{\mathrm{EM}}\sim 10^{51-52}\mathrm{ergs}/\mathrm{s}$. $\text{If}\gtrsim 1\%-10\%$ of this power is converted into gamma rays, Swift and Fermi could potentially detect these events out to large redshifts $z\sim 20$. Thus, SMSs could be sources of ultra-long gamma-ray bursts (ULGRBs), and massive Population III stars could be the progenitors that power a fraction of the long GRBs observed at redshift $z\sim 5–8$. Gravitational waves are copiously emitted during the collapse and peak at $\sim 15({10}^6{M}_{\odot }/M)\mathrm{mHz}$ [$\sim 0.15({10}^4{M}_{\odot }/M)\mathrm{Hz}$], i.e., in the LISA (DECIGO/BBO) band; optimally oriented SMSs could be detectable by LISA (DECIGO/BBO) at $z\lesssim 3$ ($z\lesssim 11$). Hence, $10^4{M}_{\odot }$ SMSs collapsing at $z\sim 10$ are promising multimessenger sources of coincident gravitational and electromagnetic waves.