We review the electro-magnetic energy at axion haloscopes and find that the electric and the corresponding magnetic energy stored in the cavity modes or, equivalently, the mode dependent electric and magnetic form factors are the same regardless of the position of the cavity inside the solenoid. Furthermore, we extend our argument to the cases satisfying $\overrightarrow{\nabla }\times {\overrightarrow{B}}_{\text{external}}=0$, where ${\overrightarrow{B}}_{\text{external}}$ is a static magnetic field provided by a magnet at an axion haloscope. Two typical magnets, solenoidal and toroidal, satisfy $\overrightarrow{\nabla }\times {\overrightarrow{B}}_{\text{external}}=0$; thus, the electric and the corresponding magnetic energy stored in the cavity modes are always the same in both cases. The energy, however, is independent of the position of the cavity in axion haloscopes with a solenoid, and depends on those with a toroidal magnet.

The dissipative dynamics of an expanding massless gas with constant cross section in a spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) universe is studied. The mathematical problem of solving the full nonlinear relativistic Boltzmann equation is recast into an infinite set of nonlinear ordinary differential equations for the moments of the one-particle distribution function. Momentum-space resolution is determined by the number of nonhydrodynamic modes included in the moment hierarchy, i.e., by the truncation order. We show that in the FLRW spacetime the nonhydrodynamic modes decouple completely from the hydrodynamic degrees of freedom. This results in the system flowing as an ideal fluid while at the same time producing entropy. The solutions to the nonlinear Boltzmann equation exhibit transient tails of the distribution function with nontrivial momentum dependence. The evolution of this tail is not correctly captured by the relaxation time approximation nor by the linearized Boltzmann equation. However, the latter probes additional high-momentum details unresolved by the relaxation time approximation. While the expansion of the FLRW spacetime is slow enough for the system to move towards (and not away from) local thermal equilibrium, it is not sufficiently slow for the system to actually ever reach complete local equilibrium. Equilibration is fastest in the relaxation time approximation, followed, in turn, by kinetic evolution with a linearized and a fully nonlinear Boltzmann collision term.

Electromagnetic field configurations with vanishing Lorentz force density are known as force-free and appear in terrestrial, space, and astrophysical plasmas. We explore a general method for finding such configurations based on formulating equations for the field lines rather than the field itself. The basic object becomes a foliation of spacetime or, in the stationary axisymmetric case, of the half-plane. We use this approach to find some new stationary and axisymmetric solutions, one of which could represent a rotating plasma vortex near a magnetic null point.

In conventional general relativity without torsion, high-frequency gravitational waves couple to the chiral number density of spin one-half quanta: the polarization of the waves is rotated by $2\pi N_5{\ell }_{\mathrm{Pl}}^2$, where $N_5$ is the chiral column density and ${\ell }_{\mathrm{Pl}}$ is the Planck length. This means that if a primordial distribution of gravitational waves with E-E or B-B correlations passed through a chiral density of fermions in the very early Universe, an E-B correlation will be generated. This in turn will give rise to E-B and T-B correlations in the cosmic microwave background (CMB). Less obviously but more primitively, the condition Albrecht called “cosmic coherence” would be violated, changing the restrictions on the class of admissible cosmological gravitational waves. This altered class of waves would, generally speaking, probe earlier physics than do the conventional waves; their effects on the CMB would be most pronounced for low ($\lesssim 100$) multipoles. Rough estimates indicate that if the tensor-to-scalar ratio is less than about ${10}^{-2}$, it will be hard to constrain a spatially homogeneous primordial $N_5$ by present data.

Rapidly rotating neutron stars are promising sources of continuous gravitational wave radiation for the LIGO and Virgo interferometers. The majority of neutron stars in our galaxy have not been identified with electromagnetic observations. All-sky searches for isolated neutron stars offer the potential to detect gravitational waves from these unidentified sources. The parameter space of these blind all-sky searches, which also cover a large range of frequencies and frequency derivatives, presents a significant computational challenge. Different methods have been designed to perform these searches within acceptable computational limits. Here we describe the first benchmark in a project to compare the search methods currently available for the detection of unknown isolated neutron stars. The five methods compared here are individually referred to as the PowerFlux, sky Hough, frequency Hough, Einstein@Home, and time domain $\mathcal{F}$-statistic methods. We employ a mock data challenge to compare the ability of each search method to recover signals simulated assuming a standard signal model. We find similar performance among the four quick-look search methods, while the more computationally intensive search method, Einstein@Home, achieves up to a factor of two higher sensitivity. We find that the absence of a second derivative frequency in the search parameter space does not degrade search sensitivity for signals with physically plausible second derivative frequencies. We also report on the parameter estimation accuracy of each search method, and the stability of the sensitivity in frequency and frequency derivative and in the presence of detector noise.

In single-field slow-roll inflation models, the height and slope of the potential are made to satisfy certain conditions to match with observations. This in turn translates into bounds on the number of $e$-foldings and the excursion of the scalar field during inflation. In this work we consider broad classes of inflationary models to study how much the field excursion starting from the horizon exit to the end of inflation, $\mathrm{\Delta }\varphi$, can vary for the set of inflationary parameters given by Planck. We also derive an upper bound on the number of $e$-foldings between the horizon exit of a cosmologically interesting mode and the end of inflation. We comment on the possibility of having super-Planckian and sub-Planckian field excursions within the framework of single-field slow-roll inflation.

Inflation occurring at energy densities less than $({10}^{14}\mathrm{GeV}{)}^4$ produces tensor perturbations too small to be measured by cosmological surveys. However, we show that it is possible to probe low scale inflation by measuring the mass of the inflaton in low energy experiments. Detection prospects and cosmological constraints are determined for low scale quartic hilltop models of inflation paired with a curvaton field, which imprints the spectrum of scalar perturbations observed in large scale structure and on the cosmic microwave background. With cosmological constraints applied, low scale quartic inflation at energies GeV–PeV can be mapped to a MeV–TeV mass inflaton resonance, discoverable through a Higgs portal coupling at upcoming collider and meson decay experiments. It is demonstrated that low scale inflatons can have detectably large couplings to Standard Model particles through a Higgs portal, permitting prompt reheating after inflation, without spoiling, through radiative corrections to the inflaton’s self-coupling, the necessary flatness of a low scale inflationary potential. A characteristic particle spectrum for a quartic inflaton-curvaton pair is identified: to within an order of magnitude, the mass of the curvaton can be predicted from the mass of the inflaton, and vice versa. Low scale inflation Higgs portal sensitivity targets are found for experiments like the LHC, SHiP, BEPC, and KEKB.

We evaluate radiative corrections to the Higgs boson couplings in the inert doublet model, in which the lightest component of the $Z_2$ odd scalar doublet field can be a dark matter candidate. The one-loop contributions to the $hVV$, $hff$, and $hhh$ couplings are calculated in the on-shell scheme, where $h$ is the Higgs boson with the mass 125 GeV, $V$ represents a weak gauge boson, and $f$ is a fermion. We investigate how the one-loop corrected Higgs boson couplings can be deviated from the predictions in the standard model under the constraints from perturbative unitarity and vacuum stability in the scenario where the model can explain current dark matter data. When the mass of the dark matter is slightly above a half of the Higgs boson mass, it would be difficult to test the model by the direct search experiments for dark matter. We find that in such a case the model can be tested at future collider experiments by either the direct search of heavier inert particles or precision measurements of the Higgs boson couplings.

Conventional supersymmetry searches rely on large missing momentum and, on that account, are unsuitable for discovering superpartners nearly degenerate with the LSP. Such “compressed regions” are best probed by dedicated strategies that exploit their unique kinematic features. We consider a case study of a compressed gluino-bino simplified spectrum, motivated by its ability to set the dark matter relic abundance via coannihilation. A kinematic variable suited to this spectrum is introduced, by which, for a gluino-bino mass splitting of 100 GeV, the discovery reach is extendable to $m_{\tilde{g}}=850\mathrm{GeV}$ (1370 GeV) at LHC center-of-mass energy 8 TeV (13 TeV) with luminosity $20{\mathrm{fb}}^{-1}$ ($3000{\mathrm{fb}}^{-1}$). The nontrivial role played by soft triggers is also discussed.

We investigate whether the stationary solution of the Fokker-Planck equation of the complex Langevin algorithm reproduces the correct expectation values. When the complex Langevin algorithm for an action $S(x)$ is convergent, it produces an equivalent complex probability distribution $P(x)$ which ideally would coincide with $e^{-S(x)}$. We show that the projected Fokker-Planck equation fulfilled by $P(x)$ may contain an anomalous term whose form is made explicit. Such a term spoils the relation $P(x)=e^{-S(x)}$, introducing a bias in the expectation values. Through the analysis of several periodic and nonperiodic one-dimensional problems, using either exact or numerical solutions of the Fokker-Planck equation on the complex plane, it is shown that the anomaly is present quite generally. In fact, an anomaly is expected whenever the Langevin walker needs only a finite time to go to infinity and come back, and this is the case for typical actions. We conjecture that the anomaly is the rule rather than the exception in the one-dimensional case; however, this could change as the number of variables involved increases.

We derive the massive Wilson coefficients for the heavy flavor contributions to the nonsinglet charged current deep-inelastic scattering structure functions $F_L^{W^{+}}(x,Q^2)-F_L^{W^{-}}(x,Q^2)$ and $F_2^{W^{+}}(x,Q^2)-F_2^{W^{-}}(x,Q^2)$ in the asymptotic region $Q^2\gg m^2$ to 3-loop order in quantum chromodynamics at general values of the Mellin variable $N$ and the momentum fraction $x$. Besides the heavy quark pair production, also the single heavy flavor excitation $s\to c$ contributes. Numerical results are presented for the charm quark contributions, and consequences on the unpolarized Bjorken sum rule and Adler sum rule are discussed.

Neutral long-lived particles (LLPs) are highly motivated by many beyond the Standard Model scenarios, such as theories of supersymmetry, baryogenesis, and neutral naturalness, and present both tremendous discovery opportunities and experimental challenges for the LHC. A major bottleneck for current LLP searches is the prediction of Standard Model backgrounds, which are often impossible to simulate accurately. In this paper, we propose a general strategy for obtaining differential, data-driven background estimates in LLP searches, thereby notably extending the range of LLP masses and lifetimes that can be discovered at the LHC. We focus on LLPs decaying in the ATLAS muon system, where triggers providing both signal and control samples are available at LHC run 2. While many existing searches require two displaced decays, a detailed knowledge of backgrounds will allow for very inclusive searches that require just one detected LLP decay. As we demonstrate for the $h\to XX$ signal model of LLP pair production in exotic Higgs decays, this results in dramatic sensitivity improvements for proper lifetimes $\gtrsim 10\mathrm{m}$. In theories of neutral naturalness, this extends reach to glueball masses far below the $\overline{b}b$ threshold. Our strategy readily generalizes to other signal models and other detector subsystems. This framework therefore lends itself to the development of a systematic, model-independent LLP search program, in analogy to the highly successful simplified-model framework of prompt searches.

Measurements are presented of the cross section for the production of at least four jets, of which at least two originate from $b$ quarks, in proton-proton collisions. Data collected with the CMS detector at the LHC at a center-of-mass energy of 7 TeV are used, corresponding to an integrated luminosity of $3{\mathrm{pb}}^{-1}$. The cross section is measured as a function of the jet transverse momentum for $p_{\mathrm{T}}>20\mathrm{GeV}$, and of the jet pseudorapidity for $|\eta |<2.4$ ($b$ jets), 4.7 (untagged jets). The correlations in azimuthal angle and $p_{\mathrm{T}}$ between the jets are also studied. The inclusive cross section is measured to be $\sigma (pp\to 2b+2j+X)=69\pm 3(\mathrm{stat})\pm 24(\mathrm{syst})\mathrm{nb}$. The $\eta$ and $p_{\mathrm{T}}$ distributions of the four jets and the correlations between them are well reproduced by event generators that combine perturbative QCD calculations at next-to-leading-order accuracy with contributions from parton showers and multiparton interactions.

The scotogenic mechanism for radiative neutrino mass is generalized to include neutron-antineutron oscillation as well as proton decay. Dark matter is stabilized by extending the notion of lepton parity to matter parity. Leptogenesis is also a possible byproduct. This framework unifies the description of all these important topics in physics beyond the standard model of particle interactions.

The change in holographic entanglement entropy (HEE) for small fluctuations about pure anti–de Sitter is given by a perturbative expansion of the area functional in terms of the change in the bulk metric and the embedded extremal surface. However, it is known that changes in the embedding appear at second order or higher. In this paper we show that these changes in the embedding can be systematically calculated in the ($2+1$)-dimensional case by accounting for the deviation of the spacelike geodesics between a spacetime and perturbations over it. Here we consider rotating BTZ as a perturbation over ${\mathrm{AdS}}_3$ and study deviations of spacelike geodesics in them. We argue that these deviations arise naturally as solutions of a “generalized geodesic deviation equation.” Using this we perturbatively calculate the changes in HEE up to second order for rotating BTZ. This expression matches with the small system size expansion of the change in HEE obtained by the proposal of Hubeny, Rangamani, and Takayanagi for rotating BTZ. We also write an alternative form of the entanglement first law for rotating BTZ. To do this one needs to go beyond the leading order in the perturbation series discussed above. That is precisely the reason we consider finding a systematic way to calculate it. To put our result on a firm footing we further show that it is this alternative first law that approaches the thermal first law in the large subsystem size limit.

Results are presented of a search for heavy stable charged particles produced in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ using a data sample corresponding to an integrated luminosity of $2.5{\mathrm{fb}}^{-1}$ collected in 2015 with the CMS detector at the CERN LHC. The search is conducted using signatures of anomalously high energy deposits in the silicon tracker and long time-of-flight measurements by the muon system. The data are consistent with the expected background, and upper limits are set on the cross sections for production of long-lived gluinos, top squarks, tau sleptons, and leptonlike long-lived fermions. These upper limits are equivalently expressed as lower limits on the masses of new states; the limits for gluinos, ranging up to 1610 GeV, are the most stringent to date. Limits on the cross sections for direct pair production of long-lived tau sleptons are also determined.

By analyzing $482{\mathrm{pb}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at $\sqrt{s}=4.009\mathrm{GeV}$ with the BESIII detector at the BEPCII collider, we measure the absolute branching fractions for the semileptonic decays $D_s^{+}\to \eta e^{+}{\nu }_e$ and $D_s^{+}\to {\eta }^{\prime }{e}^{+}{\nu }_e$ to be $B(D_s^{+}\to \eta e^{+}{\nu }_e)=(2.30\pm 0.31\pm 0.08)\%$ and $B(D_s^{+}\to {\eta }^{\prime }{e}^{+}{\nu }_e)=(0.93\pm 0.30\pm 0.05)\%$, respectively, and their ratio $\frac{B(D_s^{+}\to {\eta }^{\prime }{e}^{+}{\nu }_e)}{B(D_s^{+}\to \eta e^{+}{\nu }_e)}=0.40\pm 0.14\pm 0.02$, where the first uncertainties are statistical and the second ones are systematic. The results are in good agreement with previous measurements within uncertainties; they can be used to determine the $\eta -{\eta }^{\prime }$ mixing angle and improve upon the $D_s^{+}$ semileptonic branching ratio precision.

In general relativity, relativistic gravity gradiometry involves the measurement of the relativistic tidal matrix, which is theoretically obtained from the projection of the Riemann curvature tensor onto the orthonormal tetrad frame of an observer. The observer’s 4-velocity vector defines its local temporal axis and its local spatial frame is defined by a set of three orthonormal nonrotating gyro directions. The general tidal matrix for the timelike geodesics of Kerr spacetime has been calculated by Marck [Proc. R. Soc. A 385, 431 (1983)]. We are interested in the measured components of the curvature tensor along the inclined “circular” geodesic orbit of a test mass about a slowly rotating astronomical object of mass $M$ and angular momentum $J$. Therefore, we specialize Marck’s results to such a “circular” orbit that is tilted with respect to the equatorial plane of the Kerr source. To linear order in $J$, we recover the gravitomagnetic beating phenomenon [B. Mashhoon and D. S. Theiss, Phys. Rev. Lett. 49, 1542 (1982)], where the beat frequency is the frequency of geodetic precession. The beat effect shows up as a special long-period gravitomagnetic part of the relativistic tidal matrix; moreover, the effect’s short-term manifestations are contained in certain post-Newtonian secular terms. The physical interpretation of this effect is briefly discussed.

Previous work on the anti–de Sitter (AdS) instability problem within the two-time framework (TTF) has found an “oscillating singularity” whose presence depends on the gauge choice. We give a physical interpretation of this singularity as a diverging redshift between the boundary and the center of AdS. This signals a genuine breakdown of the linearized gravity. One can also identify the diverging redshift through a backreaction calculation purely in the boundary gauge, where the TTF result stays regular.

An analytical solution for the light trajectory in the near zone of the gravitational field of one pointlike body in arbitrary slow motion in the post-post-Newtonian approximation is presented in harmonic gauge. Expressions for total light deflection and time delay are given. The presented solution is a further step toward high-precision astrometry aiming at nanoarcsecond level of accuracy.