A search for the Higgs boson has been performed in the $H\to W{W}^{(*)}\to {\ell }^{+}\nu {\ell }^{-}\overline{\nu }$ channel ($\ell =e/\mu$) with an integrated luminosity of $2.05{\mathrm{fb}}^{-1}$ of $pp$ collisions at $\sqrt{s}=7\mathrm{TeV}$ collected with the ATLAS detector at the Large Hadron Collider. No significant excess of events over the expected background is observed and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range $110\mathrm{GeV}<m_{\mathrm{H}}<300\mathrm{GeV}$. The observations exclude the presence of a standard model Higgs boson with a mass $145<m_{\mathrm{H}}<206\mathrm{GeV}$ at 95% confidence level.

A search for the standard model Higgs boson is performed in the diphoton decay channel. The data used correspond to an integrated luminosity of $4.9{\mathrm{fb}}^{-1}$ collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=7\mathrm{TeV}$. In the diphoton mass range 110–150 GeV, the largest excess with respect to the background-only hypothesis is observed at 126.5 GeV, with a local significance of 2.8 standard deviations. Taking the look-elsewhere effect into account in the range 110–150 GeV, this significance becomes 1.5 standard deviations. The standard model Higgs boson is excluded at 95% confidence level in the mass ranges of 113–115 GeV and 134.5–136 GeV.

A search for a Higgs boson in the four-lepton decay channel $H\to ZZ$, with each $Z$ boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range of $110<m_H<600\mathrm{GeV}$. The analysis uses data corresponding to an integrated luminosity of $4.7{\mathrm{fb}}^{-1}$ recorded by the CMS detector in $pp$ collisions at $\sqrt{s}=7\mathrm{TeV}$ from the LHC. Seventy-two events are observed with four-lepton invariant mass $m_{4\ell }>100\mathrm{GeV}$ (with 13 below 160 GeV), while $67.1\pm 6.0$ ($9.5\pm 1.3$) events are expected from background. The four-lepton mass distribution is consistent with the expectation of standard model background production of $ZZ$ pairs. Upper limits at 95% confidence level exclude the standard model Higgs boson in the ranges of 134–158 GeV, 180–305 GeV, and 340–465 GeV. Small excesses of events are observed around masses of 119, 126, and 320 GeV, making the observed limits weaker than expected in the absence of a signal.

Using transmission electron microscopy, the anomalies in resistivity and magnetic susceptibility at $\sim 262\mathrm{K}$ in ${\mathrm{IrTe}}_2$ are found to accompany the superlattice peaks with $\stackrel{\rightharpoonup }{q}=(1/5,0,-1/5)$. The wave vector is consistent with our theoretical calculation for the Fermi surface nesting vector, indicating that the $\sim 262\mathrm{K}$ transition is of the charge-orbital density wave (DW) type. We also discovered that both Pd intercalation and substitution induce bulk superconductivity with $T_c$ up to $\sim 3\mathrm{K}$, which competes with DW in a quantum critical pointlike manner.

A search for time-integrated $CP$ violation in $D^0\to h^{-}{h}^{+}$ ($h=K$, $\pi$) decays is presented using $0.62{\mathrm{fb}}^{-1}$ of data collected by LHCb in 2011. The flavor of the charm meson is determined by the charge of the slow pion in the $D^{*+}\to D^0{\pi }^{+}$ and $D^{*-}\to {\overline{D}}^0{\pi }^{-}$ decay chains. The difference in $CP$ asymmetry between $D^0\to K^{-}{K}^{+}$ and $D^0\to {\pi }^{-}{\pi }^{+}$, $\Delta A_{CP}\equiv A_{CP}(K^{-}{K}^{+})-A_{CP}({\pi }^{-}{\pi }^{+})$, is measured to be $[-0.82\pm 0.21(\mathrm{stat})\pm 0.11(\mathrm{syst})]\%$. This differs from the hypothesis of $CP$ conservation by 3.5 standard deviations.

We report on the first observation of dineutron emission in the decay of ${}^{16}\mathrm{Be}$. A single-proton knockout reaction from a $53\mathrm{MeV}/\mathrm{u}$ ${}^{17}\mathrm{B}$ beam was used to populate the ground state of ${}^{16}\mathrm{Be}$. ${}^{16}\mathrm{Be}$ is bound with respect to the emission of one neutron and unbound to two-neutron emission. The dineutron character of the decay is evidenced by a small emission angle between the two neutrons. The two-neutron separation energy of ${}^{16}\mathrm{Be}$ was measured to be 1.35(10) MeV, in good agreement with shell model calculations, using standard interactions for this mass region.

We demonstrate deceleration of a beam of neutral strontium monofluoride molecules using radiative forces. Under certain conditions, the deceleration results in a substantial flux of detected molecules with velocities $\lesssim 50\mathrm{m}/\mathrm{s}$. Simulations and other data indicate that the detection of molecules below this velocity is greatly diminished by transverse divergence from the beam. The observed slowing, from $\sim 140\mathrm{m}/\mathrm{s}$, corresponds to scattering $\gtrsim {10}^4$ photons. We also observe longitudinal velocity compression under different conditions. Combined with molecular laser cooling techniques, this lays the groundwork to create slow and cold molecular beams suitable for trap loading.

Laboratory observations of enhanced loss of fast electrons trapped in a magnetic mirror geometry irradiated by shear Alfvén waves (SAW) are reported. A population of runaway electrons generated by second harmonic electron-cyclotron-resonance heating, as evidenced by the production of hard x rays with energy up to 3 MeV, is subjected to SAW launched with a rotating magnetic field antenna. It is observed that the SAW dramatically affect the trapped fast electrons and scatter them out of the magnetic mirror despite any obvious resonance. The results could have implications on the techniques of artificial reduction of energetic electrons in the inner radiation belt.

Langmuir cavitons have been artificially produced in Earth’s ionosphere, but evidence of naturally occurring cavitation has been elusive. By measuring and modeling the spectra of electrostatic plasma modes, we show that natural cavitating, or strong, Langmuir turbulence does occur in the ionosphere, via a process in which a beam of auroral electrons drives Langmuir waves, which in turn produce cascading Langmuir and ion-acoustic excitations and cavitating Langmuir turbulence. The data presented here are the first direct evidence of cavitating Langmuir turbulence occurring naturally in any space or astrophysical plasma.

In biochemical signaling, information is often encoded in oscillatory signals. However, the advantages of such a coding strategy over an amplitude-encoding scheme of constant signals remain unclear. Here we study the dynamics of a simple model gene promoter in response to oscillating and constant transcription factor signals. We find that in biologically relevant parameter regimes an oscillating input can produce a more constant protein level than a constant input. Our results suggest that oscillating signals may be used to minimize noise in gene regulation.

We show that helical magnets exhibit a nontrivial type of domain wall consisting of a regular array of vortex lines, except for a few distinguished orientations. This result follows from topological consideration and is independent of the microscopic models. We used simple models to calculate the shape and energetics of vortex walls in centrosymmetric and noncentrosymmetric crystals. Vortices are strongly anisotropic, deviating from the conventional Berezinskii-Kosterlitz-Thouless form. The width of the domain walls depend only weakly on the magnetic anisotropy, in contrast to ferromagnets and antiferromagnets. We show that vortex walls can be driven by external currents and in multiferroics also by electric fields.

Random packings of granular chains are presented as a model system to investigate the contribution of entanglements to strain stiffening. The chain packings are sheared in uniaxial compression experiments. For short chain lengths, these packings yield when the shear stress exceeds the scale of the confining pressure, similar to granular packings of unconnected particles. In contrast, packings of chains which are long enough to form loops exhibit strain stiffening, in which the effective stiffness of the material increases with strain, similar to many polymer materials. The latter packings can sustain stresses orders-of-magnitude greater than the confining pressure, and do not yield until the chain links break. X-ray tomography measurements reveal that the strain-stiffening packings contain system-spanning clusters of entangled chains.

A scannable laser beam is used to generate local thermal gradients in metallic (${\mathrm{Co}}_2\mathrm{FeAl}$) or insulating (${\mathrm{Y}}_3{\mathrm{Fe}}_5{\mathrm{O}}_{12}$) ferromagnetic thin films. We study the resulting local charge and spin currents that arise due to the anomalous Nernst effect (ANE) and the spin Seebeck effect (SSE), respectively. In the local ANE experiments, we detect the voltage in the ${\mathrm{Co}}_2\mathrm{FeAl}$ thin film plane as a function of the laser-spot position and external magnetic field magnitude and orientation. The local SSE effect is detected in a similar fashion by exploiting the inverse spin Hall effect in a Pt layer deposited on top of the ${\mathrm{Y}}_3{\mathrm{Fe}}_5{\mathrm{O}}_{12}$. Our findings establish local thermal spin and charge current generation as well as spin caloritronic domain imaging.

Using Lorenz microscopy and small-angle electron diffraction, we directly present that the chiral magnetic soliton lattice (CSL) continuously evolves from a chiral helimagnetic structure in small magnetic fields in ${\mathrm{Cr}}_{1/3}{\mathrm{NbS}}_2$. An incommensurate CSL undergoes a phase transition to a commensurate ferromagnetic state at the critical field strength. The period of a CSL, which exerts an effective potential for itinerant spins, is tuned by simply changing the field strength. Chiral magnetic orders observed do not exhibit any structural dislocation, indicating their high stability and robustness in ${\mathrm{Cr}}_{1/3}{\mathrm{NbS}}_2$.

It is shown that optomechanical forces can cause nonlinear self-channeling of light in a planar dual-slab waveguide. A system of two parallel silica nanowebs, spaced $\sim 100\mathrm{nm}$ and supported inside a fiber capillary, is studied theoretically and an iterative scheme developed to analyze its nonlinear optomechanical properties. Steady-state field distributions and mechanical deformation profiles are obtained, demonstrating that self-channeling is possible in realistic structures at launched powers as low as a few mW. The differential optical nonlinearity of the self-channeled mode can be as much as $10\times {10}^6$ times higher than the corresponding electronic Kerr nonlinearity. It is also intrinsically broadband, does not utilize resonant effects, can be viewed as a consequence of the extreme nonlocality of the mechanical response, and in fact is a notable example of a so-called accessible soliton.

Concentrated hard-sphere suspensions and glasses are investigated with rheometry, confocal microscopy, and Brownian dynamics simulations during start-up shear, providing a link between microstructure, dynamics, and rheology. The microstructural anisotropy is manifested in the extension axis where the maximum of the pair-distribution function exhibits a minimum at the stress overshoot. The interplay between Brownian relaxation and shear advection as well as the available free volume determine the structural anisotropy and the magnitude of the stress overshoot. Shear-induced cage deformation induces local constriction, reducing in-cage diffusion. Finally, a superdiffusive response at the steady state, with a minimum of the time-dependent effective diffusivity, reflects a continuous cage breakup and reformation.

We analyze 3D flight paths of bumblebees searching for nectar in a laboratory experiment with and without predation risk from artificial spiders. For the flight velocities we find mixed probability distributions reflecting the access to the food sources while the threat posed by the spiders shows up only in the velocity correlations. The bumblebees thus adjust their flight patterns spatially to the environment and temporally to predation risk. Key information on response to environmental changes is contained in temporal correlation functions, as we explain by a simple emergent model.

In a light-pulse atom interferometer, we use a tip-tilt mirror to remove the influence of the Coriolis force from Earth’s rotation and to characterize configuration space wave packets. For interferometers with a large momentum transfer and large pulse separation time, we improve the contrast by up to 350% and suppress systematic effects. We also reach what is to our knowledge the largest space-time area enclosed in any atom interferometer to date. We discuss implications for future high-performance instruments.

Recently, there has been a tremendous increase in the number of identified extrasolar planetary systems. Our understanding of their formation is tied to exoplanet internal structure models, which rely upon equations of state of light elements and compounds such as water. Here, we present shock compression data for water with unprecedented accuracy that show that water equations of state commonly used in planetary modeling significantly overestimate the compressibility at conditions relevant to planetary interiors. Furthermore, we show that its behavior at these conditions, including reflectivity and isentropic response, is well-described by a recent first-principles based equation of state. These findings advocate that this water model be used as the standard for modeling Neptune, Uranus, and “hot Neptune” exoplanets and should improve our understanding of these types of planets.

A heated semiconductor light-emitting diode at low forward bias voltage $V<k_{B}T/q$ is shown to use electrical work to pump heat from the lattice to the photon field. Here the rates of both radiative and nonradiative recombination have contributions at linear order in $V$. As a result the device’s wall-plug (i.e., power conversion) efficiency is inversely proportional to its output power and diverges as $V$ approaches zero. Experiments directly confirm for the first time that this behavior continues beyond the conventional limit of unity electrical-to-optical power conversion efficiency.