We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of $48.7[1/\sqrt{\mathrm{Hz}}]$. At the frequency of best strain sensitivity, near 100 Hz, we set 90% confidence upper limits of $1.8\times 10^{-25}$. At the low end of our frequency range, 20 Hz, we achieve upper limits of $3.9\times 10^{-24}$. At 55 Hz we can exclude sources with ellipticities greater than $10^{-5}$ within 100 pc of Earth with fiducial value of the principal moment of inertia of ${10}^{38}\mathrm{kg}{\mathrm{m}}^2$.

We present a new method for probing the hadronic interaction models at ultrahigh energy and extracting details about mass composition. This is done using the time profiles of the signals recorded with the water-Cherenkov detectors of the Pierre Auger Observatory. The profiles arise from a mix of the muon and electromagnetic components of air showers. Using the risetimes of the recorded signals, we define a new parameter, which we use to compare our observations with predictions from simulations. We find, first, inconsistencies between our data and predictions over a greater energy range and with substantially more events than in previous studies. Second, by calibrating the new parameter with fluorescence measurements from observations made at the Auger Observatory, we can infer the depth of shower maximum $X_{\max }$ for a sample of over 81,000 events extending from 0.3 to over 100 EeV. Above 30 EeV, the sample is nearly 14 times larger than what is currently available from fluorescence measurements and extending the covered energy range by half a decade. The energy dependence of $⟨X_{\max }⟩$ is compared to simulations and interpreted in terms of the mean of the logarithmic mass. We find good agreement with previous work and extend the measurement of the mean depth of shower maximum to greater energies than before, reducing significantly the statistical uncertainty associated with the inferences about mass composition.

We update the experimental moments for the charm quark as computed in [J. H. Kühn, M. Steinhauser, and C. Sturm, Nucl. Phys. B778, 192 (2007)] and used in [K. G. Chetyrkin, J. H. Kühn, A. Maier, P. Maierhöfer, P. Marquard, M. Steinhauser, and C. Sturm, Phys. Rev. D 80, 074010 (2009), K. Chetyrkin, J. H. Kühn, A. Maier, P. Maierhöfer, P. Marquard, M. Steinhauser, and C. Sturm, Theor. Math. Phys. 170, 217 (2012)] for the determination of the charm-quark mass. The new value for the $\overline{\mathrm{MS}}$ charm-quark mass reads $m_c(3\mathrm{GeV})=0.993\pm 0.008\mathrm{GeV}$.

In this paper we study the direct $CP$ asymmetry of the doubly Cabibbo-suppressed decay mode $D^0\to K^{+}{\pi }^{-}$ within standard model and two Higgs doublet model with generic Yukawa structure. In the standard model we derive the corrections to the tree level amplitude, generated from the box and dipenguin diagrams, required for generating the weak $CP$ violating phases. We show that these phases are so tiny leading to a direct $CP$ asymmetry of order ${10}^{-9}$. Regarding the two Higgs doublet model with generic Yukawa structure we derive the Wilson coefficients relevant to $D^0\to K^{+}{\pi }^{-}$. After taking into account all constraints on the parameter space of the model we show that charged Higgs couplings to quarks can lead to a direct $CP$ asymmetry of order ${10}^{-3}$ which is 6 orders of magnitude larger than the standard model prediction.

Using the example of a two-dimensional four-fermion lattice field theory we demonstrate that Feynman diagrams can generate a mass gap when massless fermions interact via a marginally relevant coupling. We introduce an infrared cutoff through the finite system size so that the perturbation series for the partition function and observables become convergent. We then use the Monte Carlo approach to sample sufficiently high orders of diagrams to expose the presence of a mass gap in the lattice model.

Smoothing of field configurations is highly important for precision calculations of physical quantities on the lattice. We present a cooling method based on stochastic quantization with a built-in UV momentum cutoff. The latter is implemented via a UV-regularized, hence colored, noise term. Our method is tested in a two-dimensional scalar field theory. We show that UV modes can be removed systematically without altering the physics content of the theory. The approach has an interpretation in terms of the nonperturbative (Wilsonian) renormalization group that facilitates the physics interpretation of the cutoff procedure. It also can be used to define the maximal colored cooling applicable without changing the theory.

We study the mass spectra and radiative decays of doubly heavy baryons within the diquark picture in a relativized quark model. The mass of the $J^P=1/2^{+}$ ${\mathrm{\Xi }}_{cc}$ ground state is predicted to be 3606 MeV, which is consistent with the mass of ${\mathrm{\Xi }}_{cc}^{++}(3621)$ newly observed by the LHCb Collaboration. The predicted mass gap between two $S$-wave states, ${\mathrm{\Xi }}_{cc}^{*}$ ($J^P=3/2^{+}$) and ${\mathrm{\Xi }}_{cc}$ ($J^P=1/2^{+}$), is 69 MeV. Furthermore, the radiative transitions of doubly heavy baryons are also estimated by using the realistic wave functions obtained from relativized quark model. The radiative decay widths of ${\mathrm{\Xi }}_{cc}^{*++}\to {\mathrm{\Xi }}_{cc}^{++}\gamma$ and ${\mathrm{\Xi }}_{cc}^{*+}\to {\mathrm{\Xi }}_{cc}^{+}\gamma$ are predicted to be about 7 and 4 keV, respectively. These predictions of doubly heavy baryons can provide helpful information for future experimental searches.

A search for dark matter in association with a Higgs boson decaying to two photons is presented. This study is based on data collected with the ATLAS detector, corresponding to an integrated luminosity of $36.1{\mathrm{fb}}^{-1}$ of proton-proton collisions at the LHC at a center-of-mass energy of 13 TeV in 2015 and 2016. No significant excess over the expected background is observed. Upper limits at 95% confidence level are set on the visible cross section for beyond the Standard Model physics processes, and the production cross section times branching fraction of the Standard Model Higgs boson decaying into two photons in association with missing transverse momentum in three different benchmark models. Limits at 95% confidence level are also set on the observed signal in two-dimensional mass planes. Additionally, the results are interpreted in terms of 90% confidence-level limits on the dark-matter–nucleon scattering cross section, as a function of the dark-matter particle mass, for a spin-independent scenario.

A noncommutative extension of an ideal (Hamiltonian) fluid model in $3+1$ dimensions is proposed. The model enjoys several interesting features: it allows a multiparameter central extension in Galilean boost algebra (which is significant being contrary to the existing belief that a similar feature can appear only in $2+1$-dimensions); noncommutativity generates vorticity in a canonically irrotational fluid; it induces a nonbarotropic pressure leading to a nonisentropic system. (Barotropic fluids are entropy preserving as the pressure depends only on the matter density.) Our fluid model is termed “exotic” since it has a close resemblance with the extensively studied planar ($2+1$ dimensions) exotic models and exotic (noncommutative) field theories.

We show that there is an inconsistency in the class of solutions obtained in Phys. Rev. D 95, 084037 (2017). This inconsistency is due to the approximate relation between Lagrangian density and its derivative for nonlinear electrodynamics. We present an algorithm to obtain new classes of solutions.

We derive the extended renormalized entanglement entropy and the Fisher information metric in the case of closed bosonic strings in a homogeneous plane wave background. Our investigations are conducted within the framework of thermo field dynamics. The formalism is also illustrated in the example of some particular models in condensed matter physics and the nonequilibrium case for a system with dissipations.

How the transverse M5-branes are described in the matrix-model formulations of M-theory has been a long-standing problem. We consider this problem for M-theory on the maximally supersymmetric pp-wave geometry, which admits transverse spherical M5-branes with zero light-cone energy. By using the localization, we directly analyze the strong coupling region of the corresponding matrix theory called the plane wave matrix model (PWMM). Under the assumption that the low-energy modes of the scalar fields in PWMM become mutually commuting in the strong coupling region, we show that the eigenvalue density of the $SO(6)$ scalars in the low-energy region exactly agrees with the shape of the spherical M5-branes in the decoupling limit. This result gives strong evidence that the transverse M5-branes are indeed contained in the matrix theory and the theory realizes a second quantization of the M-theory.

We study the long wavelength excitations in rotating QCD fluid in the presence of an external magnetic field at finite vector and axial charge densities. We consider the fluctuations of vector and axial charge currents coupled to energy and momentum fluctuations and compute the $SO(3)$ covariant dispersion relations of the six corresponding hydrodynamic modes. Among them, there are always two scalar chiral-magnetic-vortical-heat (CMVH) waves; in the absence of a magnetic field (vorticity) these waves reduce to chiral-vortical-heat (CVH) [chiral-magnetic-heat (CMH)] waves. While CMVH waves are a mixture of CMH and CVH waves, they have generally different velocities compared to the sum of velocities of the latter waves. The other four modes, which are made out of scalar-vector fluctuations, are mixed sound-Alfvén waves. We show that when the magnetic field is parallel with the vorticity, these four modes are the two ordinary sound modes together with two chiral Alfvén waves propagating along the common direction of the magnetic field and vorticity.

Quantum complexity is conjectured to probe inside of black hole horizons (or wormholes) via gauge gravity correspondence. In order to have a better understanding of this correspondence, we study time evolutions of complexities for Abelian pure gauge theories. For this purpose, we discretize the $U(1)$ gauge group as ${\mathbf{Z}}_N$ and also the continuum spacetime as lattice spacetime, and this enables us to define a universal gate set for these gauge theories and to evaluate time evolutions of the complexities explicitly. We find that to achieve a large complexity $\sim \exp (\text{entropy})$, which is one of the conjectured criteria necessary to have a dual black hole, the Abelian gauge theory needs to be maximally nonlocal.

We present results of searches for vector and pseudoscalar bosonic super-weakly interacting massive particles (WIMPs), which are dark matter candidates with masses at the keV-scale, with the XENON100 experiment. XENON100 is a dual-phase xenon time projection chamber operated at the Laboratori Nazionali del Gran Sasso. A profile likelihood analysis of data with an exposure of 224.6 live days $\times 34\mathrm{kg}$ showed no evidence for a signal above the expected background. We thus obtain new and stringent upper limits in the $(8–125)\mathrm{keV}/{\mathrm{c}}^2$ mass range, excluding couplings to electrons with coupling constants of $g_{ae}>3\times {10}^{-13}$ for pseudo-scalar and ${\alpha }^{\prime }/\alpha >2\times {10}^{-28}$ for vector super-WIMPs, respectively. These limits are derived under the assumption that super-WIMPs constitute all of the dark matter in our galaxy.

We construct closed-form gravitational waveforms (GWs) with tidal effects for the coalescence of binary neutron stars. The method relies on a new set of eccentricity-reduced and high-resolution numerical relativity (NR) simulations and is composed of three steps. First, tidal contributions to the GW phase are extracted from the time-domain NR data. Second, those contributions are employed to fix high-order coefficients in an effective and resummed post-Newtonian expression. Third, frequency-domain tidal approximants are built using the stationary phase approximation. Our tidal approximants are valid from the low frequencies to the strong-field regime. They can be analytically added to any binary black hole GW model to obtain a binary neutron star waveform, either in the time or in the frequency domain. This work provides simple, flexible, and accurate models ready to be used in both searches and parameter estimation of binary neutron star events.

The signaling between two observers in $3+1$ dimensional flat spacetime coupled locally to a nonlocal field is considered. We show that in the case where two observers are purely timelike related—so that an exchange of on-shell massless quanta cannot occur—signaling is still possible because of a violation of Huygens’ principle. In particular, we show that the signaling is exponentially suppressed by the nonlocality scale. Furthermore, we consider the case in which the two observers are lightlike related and show that the nonlocal modification to the local result is polynomially suppressed in the nonlocality scale. This may have implications for phenomenological tests of nonlocal theories.

The flavor-changing rare decay $B\to K^{*}(\to K\pi ){\ell }^{+}{\ell }^{-}$ is one of the most studied modes due to its sensitivity to physics beyond the standard model, and several discrepancies have come to light among the plethora of observables that are measured. In this paper, we revisit the analogous baryonic decay mode ${\mathrm{\Lambda }}_b\to \mathrm{\Lambda }(\to p\pi ){\ell }^{+}{\ell }^{-}$, and we present a complete set of ten angular observables that can be measured using this decay mode. Our calculations are done while retaining the finite lepton mass so that the signal of lepton non-universality observed in $B\to K^{*}{\ell }^{+}{\ell }^{-}$ can be corroborated by the corresponding baryonic decay mode. We show that due to the parity-violating nature of the subsequent $\mathrm{\Lambda }\to p\pi$ decay, there exists at least one angular asymmetry that is nonvanishing in the large-recoil limit, unlike the case in $B\to K^{*}{\ell }^{+}{\ell }^{-}$ decay mode, making it particularly sensitive to new physics that violates lepton flavor universality.

We report a comprehensive analysis of the light and strange disconnected-sea quarks contribution to the nucleon magnetic moment, charge radius, and the electric and magnetic form factors. The lattice QCD calculation includes ensembles across several lattice volumes and lattice spacings with one of the ensembles at the physical pion mass. We adopt a model-independent extrapolation of the nucleon magnetic moment and the charge radius. We have performed a simultaneous chiral, infinite volume, and continuum extrapolation in a global fit to calculate results in the continuum limit. We find that the combined light and strange disconnected-sea quarks contribution to the nucleon magnetic moment is ${\mu }_M(\mathrm{DI})=-0.022(11)(09){\mu }_N$ and to the nucleon mean square charge radius is $⟨r^2{⟩}_E(\mathrm{DI})=-0.019(05)(05){\mathrm{fm}}^2$ which is about $1/3$ of the difference between the $⟨r_p^2{⟩}_E$ of electron-proton scattering and that of a muonic atom and so cannot be ignored in obtaining the proton charge radius in the lattice QCD calculation. The most important outcome of this lattice QCD calculation is that while the combined light-sea and strange quarks contribution to the nucleon magnetic moment is small at about 1%, a negative 2.5(9)% contribution to the proton mean square charge radius and a relatively larger positive 16.3(6.1)% contribution to the neutron mean square charge radius come from the sea quarks in the nucleon. For the first time, by performing global fits, we also give predictions of the light and strange disconnected-sea quarks contributions to the nucleon electric and magnetic form factors at the physical point and in the continuum and infinite volume limits in the momentum transfer range of $0\le Q^2\le 0.5{\mathrm{GeV}}^2$.

The quantitative knowledge of heavy nuclei’s partonic structure is currently limited to rather large values of momentum fraction $x$—robust experimental constraints below $x\sim {10}^{-2}$ at low resolution scale $Q^2$ are particularly scarce. This is in sharp contrast to the free proton’s structure which has been probed in Deep Inelastic Scattering (DIS) measurements down to $x\sim {10}^{-5}$ at perturbative resolution scales. The construction of an electron-ion collider (EIC) with a possibility to operate with a wide variety of nuclei, will allow one to explore the low-$x$ region in much greater detail. In the present paper we simulate the extraction of the nuclear structure functions from measurements of inclusive and charm reduced cross sections at an EIC. The potential constraints are studied by analyzing simulated data directly in a next-to-leading order global fit of nuclear Parton Distribution Functions based on the recent EPPS16 analysis. A special emphasis is placed on studying the impact an EIC would have on extracting the nuclear gluon parton distribution function, the partonic component most prone to nonlinear effects at low $Q^2$. In comparison to the current knowledge, we find that the gluon parton distribution function can be measured at an EIC with significantly reduced uncertainties.