We present a single-domain Galerkin-collocation method to calculate puncture initial data sets for single and binary black holes, either in the trumpet or wormhole geometries. The combination of aspects belonging to the Galerkin and the collocation methods together with the adoption of spherical coordinates in all cases are shown to be very effective. We propose a unified expression for the conformal factor to describe trumpet and spinning black holes. In particular, for the spinning trumpet black holes, we exhibit the deformation of the limit surface due to the spin from a sphere to an oblate spheroid. We also revisit the energy content in the trumpet and wormhole puncture data sets. The algorithm can be extended to describe binary black holes.

The covariance matrix of the matter and halo power spectrum and bispectrum are studied. Using a large suite of simulations, we find that the non-Gaussianity in the covariance is significant already at mildly nonlinear scales. We compute the leading disconnected non-Gaussian correction to the matter bispectrum covariance using perturbation theory, and find that the corrections result in good agreement in the mildly nonlinear regime. The shot noise contribution to the halo power spectrum and bispectrum covariance is computed using the Poisson model, and the model yields decent agreement with simulation results. However, when the shot noise is estimated from the individual realization, which is usually done in reality, we find that the halo covariance is substantially reduced and gets close to the Gaussian covariance. This is because most of the non-Gaussianity in the covariance arises from the fluctuations in the Poisson shot noise. We use the measured non-Gaussian covariance to access the information content of the power spectrum and bispectrum. The signal-to-noise ratio (S/N) of the matter and halo power spectrum levels off in the mildly nonlinear regime, $k\sim 0.1–0.2{\mathrm{Mpc}}^{-1}h$. In the nonlinear regime the S/N of the matter and halo bispectrum increases but much slower than the Gaussian results suggest. We find that both the S/N for power spectrum and bispectrum are overestimated by the Gaussian covariances, but the problem is much more serious for the bispectrum. Because the bispectrum is affected strongly by nonlinearity and shot noise, inclusion of the bispectrum only adds a modest amount of S/N compared to that of the power spectrum.

The effects of both bulk and shear viscosities on the perturbations relevant for structure formation in late time cosmology are analyzed. It is shown that shear viscosity can be as effective as the bulk viscosity at suppressing the growth of perturbations and delaying the nonlinear regime. A statistical analysis of the shear and bulk viscous effects is performed, and some constraints on these viscous effects are given.

We continue a comprehensive numerical study of semilocal string networks and their cosmological evolution. These can be thought of as hybrid networks comprised of (nontopological) string segments, whose core structure is similar to that of Abelian Higgs vortices, and whose ends have long–range interactions and behavior similar to that of global monopoles. Our study provides further evidence of a linear scaling regime, already reported in previous studies, for the typical length scale and velocity of the network. We introduce a new algorithm to identify the position of the segment cores. This allows us to determine the length and velocity of each individual segment and follow their evolution in time. We study the statistical distribution of segment lengths and velocities for radiation- and matter-dominated evolution in the regime where the strings are stable. Our segment detection algorithm gives higher length values than previous studies based on indirect detection methods. The statistical distribution shows no evidence of (anti)correlation between the speed and the length of the segments.

The strong gravitational field around a proto-neutron star can modify the neutrino flavor transformations that occur above the neutrinosphere via three general relativistic (GR) effects: time dilation, energy redshift, and trajectory bending. Depending on the compactness of the central object, the neutrino self-interaction potential is up to three times as large as that without GR principally due to trajectory bending which increases the intersection angles between different neutrino trajectories, and time dilation which changes the fluxes. We determine whether GR effects are important for flavor transformation during the different epochs of a supernova by using multiangle flavor transformation calculations and consider a density profile and neutrino spectra representative of both the accretion and cooling phases. We find the GR effects are smaller during the accretion phase due to low compactness of the proto-neutron star and merely delay the decoherence; the neutrino bipolar oscillations during the cooling phase are also delayed due to the GR effects but the delay may be more important because the delay occurs at radii where it might alter the nucleosynthesis in the neutrino driven wind.

Growing evidence reveals universal hardening on various cosmic ray spectra, e.g., proton, positron, as well as antiproton fractions. Such universality may indicate they have a common origin. In this paper, we argue that these widespread excesses can be accounted for by a nearby supernova remnant surrounded by a giant molecular cloud. Secondary cosmic rays ($\mathrm{p}$, ${\mathrm{e}}^{+}$) are produced through the collisions between the primary cosmic-ray nuclei from this supernova remnant and the molecular gas. Different from the background, which is produced by the ensemble of a large number of sources in the Milky Way, the local injected spectrum can be harder. The time-dependent transport of particles would make the propagated spectrum even harder. Under this scenario, the anomalies of both primary ($\mathrm{p}$, ${\mathrm{e}}^{-}$) and secondary (${\mathrm{e}}^{+}$, $\overline{\mathrm{p}}/\mathrm{p}$) cosmic rays can be properly interpreted. We further show that the TeV to sub-PeV anisotropy of the proton is consistent with the observations if the local source is relatively young and lying at the anti-Galactic center direction.

We study the leptonic and semileptonic $D$-meson decays ($D\to {\mathit{\ell }}^{+}{\nu }_{\mathit{\ell }}$ and $D\to K^{(*)}{\mathit{\ell }}^{+}{\nu }_{\mathit{\ell }}$) in the framework of covariant quark model with built-in infrared confinement. We compute the required form factors in the entire kinematical momentum transfer region. The calculated form factors are used to evaluate the branching fractions of these transitions. We determine the following ratios of the partial widths: $\mathrm{\Gamma }(D^0\to K^{-}{e}^{+}{\nu }_e)/\mathrm{\Gamma }(D^{+}\to {\overline{K}}^0{e}^{+}{\nu }_e)=1.02$, $\mathrm{\Gamma }(D^0\to K^{-}{\mu }^{+}{\nu }_{\mu })/\mathrm{\Gamma }(D^{+}\to {\overline{K}}^0{\mu }^{+}{\nu }_{\mu })=0.99$ and $\mathrm{\Gamma }(D^{+}\to {\overline{K}}^0{\mu }^{+}{\nu }_{\mu })/\mathrm{\Gamma }(D^{+}\to {\overline{K}}^0{e}^{+}{\nu }_e)=0.97$ which are in close resemblance with the isospin invariance and experimental results.

The two-flavor quark-meson model is used as a low-energy effective model for QCD to study inhomogeneous chiral condensates at finite baryon chemical potential ${\mu }_B$. The parameters of the model are determined by matching the meson and quark masses, and the pion decay constant to their physical values using the on-shell and modified minimal subtraction schemes. Using a chiral-density wave ansatz for the inhomogeneity, we calculate the effective potential in the mean-field approximation and the result is completely analytic. The size of the inhomogeneous phase depends sensitively on the pion mass and whether one includes the vacuum fluctuations or not. Finally, we briefly discuss the mean-field phase diagram.

We optimize the pulse shape and polarization of time-dependent electric fields to maximize the production of electron-positron pairs via strong field quantum electrodynamics processes. The pulse is parametrized in Fourier space by a $B$-spline polynomial basis, which results in a relatively low-dimensional parameter space while still allowing for a large number of electric field modes. The optimization is performed by using a parallel implementation of the differential evolution, one of the most efficient metaheuristic algorithms. The computational performance of the numerical method and the results on pair production are compared with a local multistart optimization algorithm. These techniques allow us to determine the pulse shape and field polarization that maximize the number of produced pairs in computationally accessible regimes.

We study the sensitivity to sub-GeV dark sectors of high energy ($\ge 100\mathrm{GeV}$) proton fixed target experiments such as the Main Injector and the future Long-Baseline Neutrino Facility (LBNF). We focus on off-axis detectors since they have been shown to be the ideal location to reduce the neutrino background. We consider MiniBooNE as an off-axis detector for the NuMI facility and a hyphotetical detector for LBNF located 200 m away from the target and 6.5 degrees off-axis. We find that with the existing data, MiniBooNE can explore new regions of the parameter space for leptophobic dark forces in the 100 MeV–few GeV mass range. The dedicated MiniBooNE run in beam dump mode would further improve the reach for even lighter masses. Therefore, MiniBooNE has the potential to be one of the most sensitive probes of leptophobic dark forces for masses between 1 MeV–10 GeV. Hence we encourage MiniBooNE collaboration to perform a DM dedicated analysis of the existing data coming from neutrinos produced at the Main Injector.

The grand unified group ${\mathrm{E}}_6$ is a predictive scheme for physics beyond the standard model (SM). It offers the possibility of extra $Z$ bosons, new vectorlike fermions, sterile neutrinos, and neutral scalars in addition to the SM Higgs boson. Some previous discussions of these features are updated and extended. Their relevance to present searches at the CERN Large Hadron Collider and in patterns of neutrino masses is noted. Addition of a small set of scalar bosons at the TeV scale permits gauge unification near a scale of $10^{16}\mathrm{GeV}$ and leads to bounds on masses of particles beyond those in the standard model.

We discuss a new technique to evaluate integrals of QCD Green’s functions in the Euclidean based on their Mellin-Barnes representation. We present as a first application the evaluation of the lowest order hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon $\frac{1}{2}(g_{\mu }-2{)}_{\mathrm{HVP}}\equiv a_{\mu }^{\mathrm{HVP}}$. It is shown that with a precise determination of the slope and curvature of the HVP function at the origin from lattice QCD (LQCD), one can already obtain a result for $a_{\mu }^{\mathrm{HVP}}$ which may serve as a test of the determinations based on experimental measurements of the $e^{+}{e}^{-}$ annihilation cross section into hadrons.

Discussing four-point Green functions of bilinear quark currents in large-$N_c$ QCD, we formulate rigorous criteria for selecting diagrams appropriate for the analysis of potential tetraquark poles. We find that both flavor-exotic and cryptoexotic (i.e., flavor-nonexotic) tetraquarks, if such poles exist, have a width of order $O(1/N_c^2)$, so they are parametrically narrower compared to the ordinary $\overline{q}q$ mesons, which have a width of order $O(1/N_c)$. Moreover, for flavor-exotic states, the consistency of the large-$N_c$ behavior of “direct” and “recombination” Green functions requires two narrow flavor-exotic states, each coupling dominantly to one specific meson-meson channel.

We complement studies of the neutral pion transition form factor ${\pi }^0\to {\gamma }^{(*)}{\gamma }^{(*)}$ with calculations for the electromagnetic decay widths of the processes ${\pi }^0\to e^{+}{e}^{-}$, ${\pi }^0\to e^{+}{e}^{-}\gamma$ and ${\pi }^0\to e^{+}{e}^{-}{e}^{+}{e}^{-}$. Their common feature is that the singly or doubly virtual transition form factor serves as a vital input that is tested in the nonperturbative low-momentum region of QCD. We determine this form factor from a well-established and symmetry-preserving truncation of the Dyson-Schwinger equations. Our results for the three- and four-body decays match results of previous theoretical calculations and experimental measurements. For the rare decay we employ a numerical method to calculate the process directly by deforming integration contours, which in principle can be generalized to arbitrary integrals as long as the analytic structure of the integrands are known. Our result for the rare decay is in agreement with dispersive calculations but still leaves a $2\sigma$ discrepancy between theory and experiment.

We present a kinetic description of Bose-Einstein condensation for particle systems being out of thermal equilibrium, which may happen for gluons produced in the early stage of ultrarelativistic heavy-ion collisions. The dynamics of bosons towards equilibrium is described by a Boltzmann equation including Bose factors. To solve the Boltzmann equation with the presence of a Bose-Einstein condensate we make further developments of the kinetic transport model BAMPS (Boltzmann approach of multiparton scatterings). In this work we demonstrate the correct numerical implementations by comparing the final numerical results to the expected solutions at thermal equilibrium for systems with and without the presence of Bose-Einstein condensate. In addition, the onset of the condensation in an overpopulated gluon system is studied in more details. We find that both expected power-law scalings denoted by the particle and energy cascade are observed in the calculated gluon distribution function at infrared and intermediate momentum regions, respectively. Also, the time evolution of the hard scale exhibits a power-law scaling in a time window, which indicates that the distribution function is approximately self-similar during that time.

We have searched for proton decays into a charged antilepton ($e^{+}$, ${\mu }^{+}$) plus a meson ($\eta$, ${\rho }^0$, $\omega$) and for neutron decays into a charged antilepton ($e^{+}$, ${\mu }^{+}$) plus a meson (${\pi }^{-}$, ${\rho }^{-}$) using Super-Kamiokande I-IV data, corresponding to $0.316\text{megaton}·\text{years}$ of exposure. This measurement updates the previous published result by using 2.26 times more data and improved analysis methods. No significant evidence for nucleon decay is observed and lower limits on the partial lifetime of the nucleon are obtained. The limits range from $3\times {10}^{31}$ to $1\times {10}^{34}\text{years}$ at 90% confidence level, depending on the decay mode.

Using $2.93{\mathrm{fb}}^{-1}$ of data taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we study the semileptonic decays $D^{+}\to {\overline{K}}^0{e}^{+}{\nu }_e$ and $D^{+}\to {\pi }^0{e}^{+}{\nu }_e$. We measure the absolute decay branching fractions $\mathcal{B}(D^{+}\to {\overline{K}}^0{e}^{+}{\nu }_e)=(8.60\pm 0.06\pm 0.15)\times {10}^{-2}$ and $\mathcal{B}(D^{+}\to {\pi }^0{e}^{+}{\nu }_e)=(3.63\pm 0.08\pm 0.05)\times {10}^{-3}$, where the first uncertainties are statistical and the second systematic. We also measure the differential decay rates and study the form factors of these two decays. With the values of $|V_{cs}|$ and $|V_{cd}|$ from Particle Data Group fits assuming Cabibbo-Kobayashi-Maskawa (CKM) unitarity, we obtain the values of the form factors at $q^2=0$, $f_{+}^K(0)=0.725\pm 0.004\pm 0.012$, and $f_{+}^{\pi }(0)=0.622\pm 0.012\pm 0.003$. Taking input from recent lattice QCD calculations of these form factors, we determine values of the CKM matrix elements $|V_{cs}|=0.944\pm 0.005\pm 0.015\pm 0.024$ and $|V_{cd}|=0.210\pm 0.004\pm 0.001\pm 0.009$, where the third uncertainties are theoretical.

We present Bogomolny-Prasad-Sommerfield (BPS) indices of the supergroup Wess-Zumino-Witten (WZW) models that live on intersecting M2-M5-brane systems. They can encode data of the stretched M2-branes between M5-branes and count the BPS states. They are generally expressed in terms of mock theta functions via the Kac-Wakimoto character formula of the affine Lie superalgebra. We give an explicit expression of the index for the $PSL(2|2{)}_{k=1}$ WZW model in terms of the second-order multivariable Appell-Lerch sum. It indicates that wall crossing occurs in the BPS state counting due to the $C$ field on the M5-branes.

We propose formulas for the $1/N$ correction to the sphere free energy of theories with 4-fermion interactions, which are conformal for $d>2$. We also propose a formula for the scalar $O(N)$ model. Expanding these formulas in small $\epsilon$ near various integer dimensions, we find a perfect agreement with results obtained using the $\epsilon$-expansion technique. In $d=3$, the large $N$ results with the $1/N$ correction included are in good agreement with the Pade resummed $\epsilon$ expansion.

We investigate the entanglement entropy and the information flow of two-dimensional moving mirrors. Here we point out that various mirror trajectories can help to mimic different candidate resolutions to the information loss paradox following the semiclassical quantum field theory: (i) a suddenly stopping mirror corresponds to the assertion that all information is attached to the last burst, (ii) a slowly stopping mirror corresponds to the assertion that thermal Hawking radiation carries information, and (iii) a long propagating mirror corresponds to the remnant scenario. Based on such analogy, we find that the last burst of a black hole cannot contain enough information, while slowly emitting radiation can restore unitarity. For all cases, there is an apparent inconsistency between the picture based on quantum entanglements and that based on the semiclassical quantum field theory. Based on the quantum entanglement theory, a stopping mirror will generate a firewall-like violent emission which is in conflict with notions based on the semiclassical quantum field theory.