A half–Bogomol’nyi-Prasad-Sommerfeld circular Wilson loop in $\mathcal{N}=4$ $SU(N)$ supersymmetric Yang-Mills theory in an arbitrary representation is described by a Gaussian matrix model with a particular insertion. The additional entanglement entropy of a spherical region in the presence of such a loop was recently computed by Lewkowycz and Maldacena using exact matrix model results. In this paper we utilize the supergravity solutions that are dual to such Wilson loops in a representation with order $N^2$ boxes to calculate this entropy holographically. Employing the matrix model results of Gomis, Matsuura, Okuda and Trancanelli we express this holographic entanglement entropy in a form that can be compared with the calculation of Lewkowycz and Maldacena. We find complete agreement between the matrix model and holographic calculations.

We compute the scattering cross section of Reissner-Nordström black holes for the case of an incident electromagnetic wave. We describe how scattering is affected by both the conversion of electromagnetic to gravitational radiation, and the parity dependence of phase shifts induced by the black hole charge. The latter effect creates a helicity-reversed scattering amplitude that is nonzero in the backward direction. We show that from the character of the electromagnetic wave scattered in the backward direction it is possible, in principle, to infer if a static black hole is charged.

We present the first results of searches for axions and axionlike particles with the XENON100 experiment. The axion-electron coupling constant, $g_{\mathrm{Ae}}$, has been probed by exploiting the axioelectric effect in liquid xenon. A profile likelihood analysis of 224.6 live days $\times$ 34-kg exposure has shown no evidence for a signal. By rejecting $g_{\mathrm{Ae}}$ larger than $7.7\times {10}^{-12}$ (90% C.L.) in the solar axion search, we set the best limit to date on this coupling. In the frame of the DFSZ and KSVZ models, we exclude QCD axions heavier than 0.3 and $80\mathrm{eV}/{\mathrm{c}}^2$, respectively. For axionlike particles, under the assumption that they constitute the whole abundance of dark matter in our galaxy, we constrain $g_{\mathrm{Ae}}$ to be lower than $1\times {10}^{-12}$ (90% C.L.) for masses between 5 and $10\mathrm{keV}/{\mathrm{c}}^2$.

An improved measurement of the mass of the Higgs boson is derived from a combined fit to the reconstructed invariant mass spectra of the decay channels $H\to \gamma \gamma$ and $H\to Z{Z}^{*}\to 4\ell$. The analysis uses the $pp$ collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at center-of-mass energies of 7 TeV and 8 TeV, corresponding to an integrated luminosity of $25{\mathrm{fb}}^{-1}$. The measured value of the Higgs boson mass is $m_H=125.36\pm 0.37(\text{stat})\pm 0.18(\text{syst})\mathrm{GeV}$. This result is based on improved energy-scale calibrations for photons, electrons, and muons as well as other analysis improvements, and supersedes the previous result from ATLAS. Upper limits on the total width of the Higgs boson are derived from fits to the invariant mass spectra of the $H\to \gamma \gamma$ and $H\to Z{Z}^{*}\to 4\ell$ decay channels.

In this paper we discuss search strategies at the LHC for light electroweak gauginos which are mostly wino-like, Higgsino-like or an admixture. These states are typically degenerate with decay products that are less energetic and hence difficult to detect. In addition, their production cross sections at a hadron collider are suppressed compared to colored states such as the gluinos. In order to detect these states one needs to trigger on initial-or final-state radiation. Many previous analyses have focussed on mono-jet and mono-photon triggers. In this paper we argue and show that these triggers are unlikely to succeed, due to the large background from QCD backgrounds for the mono-jet searches and the fact that the $p_T$ distribution of the mono-photons are rapidly decreasing functions of $p_T$. We show this with both an analytic calculation of photons in the initial-state radiation and also a detailed numerical analysis. We then argue that mono-$Z$ triggers, from $Z$ decaying into charged leptons may well provide the best search strategy, in particular for Higgsino-like and mixed cases.

Indirect constraints on the total Higgs width ${\mathrm{\Gamma }}_h$ from correlating Higgs signal strengths with cross-section measurements in the off-shell region for $p(g)p(g)\to 4\ell$ production have received considerable attention recently, and the CMS Collaboration have published a first measurement. We revisit this analysis from a new physics and unitarity constraints perspective and conclude that limits on ${\mathrm{\Gamma }}_h$ obtained in this fashion are not reliable unless we make model-specific assumptions, which cannot be justified at the current stage of the LHC program. Relaxing the ${\mathrm{\Gamma }}_h$ interpretation, we discuss the merits of high invariant mass cross-section measurements in the context of Higgs $\mathcal{C}\mathcal{P}$ analyses, higher-dimensional operator testing, and resolved new physics in the light of electroweak precision constraints beyond effective theory limitations. Furthermore, we show that a rather model-independent LHC constraint can be obtained from adapting the $gg\to 4\ell$ analysis to the weak boson fusion channels at lower statistical yield.

We explore the cosmological consequences of kinetically mixed dark photons with a mass between 1 MeV and 10 GeV and an effective electromagnetic fine structure constant as small as $10^{-38}$. We calculate the freeze-in abundance of these dark photons in the early universe and explore the impact of late decays on big bang nucleosynthesis and the cosmic microwave background. This leads to new constraints on the parameter space of mass $m_V$ vs kinetic mixing parameter $\kappa$.

We revisit the computation of logarithmic corrections to black holes with $\mathcal{N}\ge 2$ supersymmetry. We employ an on-shell method that takes advantage of the symmetries in the ${\mathrm{AdS}}_2\times S^2$ near horizon geometry. For bulk modes interactions are incorporated through the spectrum of chiral primaries that we derive afresh. The spectrum of boundary states is computed explicitly by analyzing gauge variations. Elementary heat kernels in four and two dimensions then give the logarithmic corrections to the black hole entropy. Our computation represents a streamlined and simplified derivation that agrees with the results recently found by A. Sen.

We analyze the two-Higgs-doublet models (2HDMs) of Type I and Type II for consistency with the latest measurements of the $\sim 125.5\mathrm{GeV}$ Higgs-like signal at the LHC. To this end, we perform scans of the 2HDM parameter space taking into account all relevant pre-LHC constraints as well as the most recent limits coming from searches for heavy Higgs-like states at the LHC. The current status of the 2HDMs of Type I and Type II is discussed assuming that the observed 125.5 GeV state is one of the two $CP$-even Higgs bosons, either the lighter $h$ or the heavier $H$. Implications for future experiments, including expectations regarding other lighter or heavier Higgs bosons, are given. The possible importance of heavier Higgs bosons feeding the signals for the 125.5 GeV state is also evaluated.

The post-Newtonian (PN) approximation is still the most widely used approach to obtaining explicit solutions in general relativity, especially for the relativistic two-body problem with arbitrary mass ratio. Within many of its applications, it is often required to use a regularization procedure. Though frequently misunderstood, the regularization is essential for waveform generation without reference to the internal structure of orbiting bodies. In recent years, direct comparison with the self-force approach, constructed specifically for highly relativistic particles in the extreme mass ratio limit, has enabled preliminary confirmation of the foundations of both computational methods, including their very independent regularization procedures, with high numerical precision. In this paper, we build upon earlier work to carry this comparison still further, by examining next-to-next-to-leading order contributions beyond the half integral 5.5PN conservative effect, which arise from terms to cubic and higher orders in the metric and its multipole moments, thus extending scrutiny of the post-Newtonian methods to one of the highest orders yet achieved. We do this by explicitly constructing tail-of-tail terms at 6.5 and 7.5PN order, computing the redshift factor for compact binaries in the small mass ratio limit, and comparing directly with numerically and analytically computed terms in the self-force approach, obtained using solutions for metric perturbations in the Schwarzschild space-time, and a combination of exact series representations possibly with more typical PN expansions. While self-force results may be relativistic but with restricted mass ratio, our methods, valid primarily in the weak-field slowly moving regime, are nevertheless in principle applicable for arbitrary mass ratios.

We study the entanglement entropy of excited states in two-dimensional conformal field theories (CFTs). In particular, we consider excited states obtained by acting on a vacuum with primary operators. We show that the entanglement entropy increases by a finite constant amount under its time evolution. Moreover, in rational conformal field theories, we prove that this increase of the (both Renyi and von Neumann) entanglement entropy always coincides with the log of the quantum dimension of the primary operator.

We prove the generalized covariant entropy bound, $\mathrm{\Delta }S\le (A-A^{\prime })/4G\hslash$, for light-sheets with initial area $A$ and final area $A^{\prime }$. The entropy $\mathrm{\Delta }S$ is defined as a difference of von Neumann entropies of an arbitrary state and the vacuum, with both states restricted to the light-sheet under consideration. The proof applies to free fields, in the limit where gravitational backreaction is small. We do not assume the null energy condition. In regions where it is violated, we find that the bound is protected by the defining property of light-sheets: that their null generators are nowhere expanding.

We discuss the general structure and observational consequences of some of the simplest versions of chaotic inflation in supergravity in relation to the data by Planck 2013 and BICEP2. We show that minimal modifications to the simplest quadratic potential are sufficient to provide a controllable tensor mode signal and a suppression of CMB power at large angular scales.

We present calculations in which an energetic light quark shoots through a finite slab of strongly coupled $\mathcal{N}=4$ supersymmetric Yang-Mills (SYM) plasma, with thickness $L$, focusing on what comes out on the other side. We find that even when the “jets” that emerge from the plasma have lost a substantial fraction of their energy they look in almost all respects like “jets” in vacuum with the same reduced energy. The one possible exception is that the opening angle of the “jet” is larger after passage through the slab of plasma than before. Along the way, we obtain a fully geometric characterization of energy loss in the strongly coupled plasma and show that $d{E}_{\text{out}}/dL\propto L^2/\sqrt{x_{\text{stop}}^2-L^2}$, where $E_{\text{out}}$ is the energy of the “jet” that emerges from the slab of plasma and $x_{\text{stop}}$ is the (previously known) stopping distance for the light quark in an infinite volume of plasma.

We investigate electron-positron pair creation from the vacuum in a pulsed electric background field. Employing the Sauter-type pulsed field $E(t)=E_0{\text{sech}}^2(t/\tau )$ with height $E_0$ and width $\tau$, we demonstrate explicitly the interplay between the nonperturbative and perturbative aspects of pair creation in the background field. We analytically compute the number of produced pairs from the vacuum in the Sauter-type field, and the result reproduces Schwinger’s nonperturbative formula in the long pulse limit (the constant field limit), while in the short pulse limit it coincides with the leading-order perturbative result. We show that two dimensionless parameters $\nu =|e{E}_0|{\tau }^2$ and $\gamma =|e{E}_0|\tau /m_e$ characterize the importance of multiple interactions with the fields and the transition from the perturbative to the nonperturbative regime. We also find that pair creation is enhanced compared to Schwinger’s formula when the field strength is relativity weak $|e{E}_0|/m_e^2\lesssim 1$ and the pulse duration is relatively short $m_e\tau \lesssim 1$, and reveal that the enhancement is predominantly described by the lowest order perturbation with a single photon.

We detail the construction of the most general asymptotically flat, stationary, rotating, nonextremal, dyonic black hole of the four-dimensional $\mathcal{N}=2$ supergravity coupled to 3 vector multiplets that describes the $STU$ model. It generates through U dualities the most general asymptotically flat, stationary black hole of $\mathcal{N}=8$ supergravity. We develop the solution generating technique based on $\mathrm{SO}(4,4)/\mathrm{SL}(2,\mathbb{R}{)}^4$ coset model symmetries, with an emphasis on the 4-fold permutation symmetry of the gauge fields. We indicate how previously known nonextremal and extremal solutions of the $STU$ model are recovered as limiting cases. Several properties of the general black hole solution are discussed, including its thermodynamics, the quadratic mass formula, the Bogomolny-Prasad-Sommerfield limit, the slow and fast extremal rotating limits, its properties in regards to the Kerr/conformal field theory correspondence, its Killing tensors and the separability of geodesic motion and probe scalars.

The 21 cm line provides a powerful probe of astrophysics and cosmology at high redshifts, but unlocking the potential of this probe requires the robust mitigation of foreground contaminants that are typically several orders of magnitude brighter than the cosmological signal. Recent simulations and observations have shown that the smooth spectral structure of foregrounds combines with instrument chromaticity to contaminate a “wedge”-shaped region in cylindrical Fourier space. While previous efforts have explored the suppression of foregrounds within this wedge, as well as the avoidance of this highly contaminated region, all such efforts have neglected a rigorous examination of the error statistics associated with the wedge. Using a quadratic estimator formalism applied to the interferometric measurement equation, we provide a framework for such a rigorous analysis (incorporating a fully covariant treatment of errors). Additionally, we find that there are strong error correlations at high spatial wave numbers that have so far been neglected in sensitivity derivations. These error correlations substantially degrade the sensitivity of arrays relying on contributions from long baselines, compared to what one would estimate assuming uncorrelated errors.

We introduce a new method to search for the lepton-flavor violating Higgs decays $h\to {\tau }^{\pm }{\mu }^{\mp }$ and $h\to {\tau }^{\pm }{e}^{\mp }$ in the leptonic $\tau$ decay channel. In particular, the Standard Model background is estimated in a fully data driven way. The method exploits the asymmetry between electrons and muons in the final state of signal events and is sensitive to differences in the rates of the two decays. Using this method, we investigate the LHC sensitivity to these processes. With $20{\mathrm{fb}}^{-1}$ of data at $\sqrt{s}=8\mathrm{TeV}$, we expect a $3\sigma$ sensitivity for observing branching ratios of order 0.9%. The method and the suggested statistical treatment are discussed in detail.

Recently, the one-loop free energy of higher spin (HS) theories in Euclidean ${\mathrm{AdS}}_{d+1}$ was calculated and matched with the order $N^0$ term in the free energy of the large $N$ “vectorial” scalar CFT on the $S^d$ boundary. Here we extend this matching to the boundary theory defined on $S^1\times S^{d-1}$, where the length of $S^1$ may be interpreted as the inverse temperature. It has been shown that the large $N$ limit of the partition function on $S^1\times S^2$ in the $U(N)$ singlet sector of the CFT of $N$ free complex scalars matches the one-loop thermal partition function of the Vasiliev theory in ${\mathrm{AdS}}_4$, while in the $O(N)$ singlet sector of the CFT of $N$ real scalars it matches the minimal theory containing even spins only. We extend this matching to all dimensions $d$. We also calculate partition functions for the singlet sectors of free fermion CFTs in various dimensions and match them with appropriately defined higher spin theories, which for $d>3$ contain massless gauge fields with mixed symmetry. In the zero-temperature case $R\times S^{d-1}$ we calculate the Casimir energy in the scalar or fermionic CFT and match it with the one-loop correction in the global ${\mathrm{AdS}}_{d+1}$. For any odd-dimensional CFT the Casimir energy must vanish on general grounds, and we show that the HS duals obey this. In the $U(N)$ symmetric case, we exhibit the vanishing of the regularized one-loop Casimir energy of the dual HS theory in ${\mathrm{AdS}}_{d+1}$. In the minimal HS theory the vacuum energy vanishes for odd $d$ while for even $d$ it is equal to the Casimir energy of a single conformal scalar in $R\times S^{d-1}$ which is again consistent with AdS/CFT, provided the minimal HS coupling constant is $\sim 1/(N-1)$. We demonstrate analogous results for singlet sectors of theories of $N$ Dirac or Majorana fermions. We also discuss extensions to CFTs containing $N_f$ flavors in the fundamental representation of $U(N)$ or $O(N)$.

We revisit the classic $O(N)$ symmetric scalar field theories in $d$ dimensions with interaction $({\varphi }^i{\varphi }^i{)}^2$. For $2<d<4$ these theories flow to the Wilson-Fisher fixed points for any $N$. A standard large $N$ Hubbard-Stratonovich approach also indicates that, for $4<d<6$, these theories possess unitary UV fixed points. We propose their alternate description in terms of a theory of $N+1$ massless scalars with the cubic interactions $\sigma {\varphi }^i{\varphi }^i$ and ${\sigma }^3$. Our one-loop calculation in $6-\epsilon$ dimensions shows that this theory has an IR stable fixed point at real values of the coupling constants for $N>1038$. We show that the $1/N$ expansions of various operator scaling dimensions match the known results for the critical $O(N)$ theory continued to $d=6-\epsilon$. These results suggest that, for sufficiently large $N$, there are 5-dimensional unitary $O(N)$ symmetric interacting conformal field theories (CFTs); they should be dual to the Vasiliev higher-spin theory in ${\mathrm{AdS}}_6$ with alternate boundary conditions for the bulk scalar. Using these CFTs we provide a new test of the 5-dimensional $F$ theorem, and also find a new counterexample for the $C_T$ theorem.