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We examine the large-x QCD evolution of the twist-three gluonic-pole strength defining an effective T-odd Sivers function, where evolution of the T-even transverse-spin DIS structure function g₂ is multiplicative. The result corresponds to a colour-factor modified spin-averaged twist-two evolution.

The photoproduction of K⁺ mesons is an important challenge to recent QCD based chiral perturbation theories in the strange quark sector and is an important constraint on the nucleon excitation spectrum. We present preliminary data from a new high precision measurement using the Crystal Ball detector. The measurement pioneers a new technique for tagging strangeness using detailed cluster analysis in segmented calorimeters which has potential wider application at present and future hadron physics facilities.

The top quark is the heaviest elementary particle and unique among the known quarks since it decays before forming hadronic bound states. This makes measurements of the top quark itself particularly interesting as one can access directly the properties of a bare quark. The latest measurements of these properties with the ATLAS detector are reported using data from 8 TeV and 13 TeV proton-proton collisions at the Large Hadron Collider at CERN. The latest measurements of the top quark mass using template methods, as well as others aiming to measure the mass in a well-defined scheme, are presented. In addition, measurements for the top quark decay width, top quark spin observables and $W$-boson helicity in events with top quark pairs ($t\bar{t}$) are presented and compared to the Standard Model predictions. The cross-section measurements of top quark pair production in association with a photon, $Z$- or $W$-boson are also reported and compared to the most accurate theoretical calculations. These measurements probe the top quark electroweak couplings. Limits on the rate of flavour-changing neutral current processes in the production or decay of the top quark are also shown.

Brands are capitalising on outrage via social media platforms to gain attention and influence behaviour, all while furthering commercial gain. The strategic use of polarising content constitutes a dynamic era of brand performance, often emerging via brand activism. The goal of modern activist messaging is to break into filter bubbles and keep users engaged and responsive. In this way, brand strategy has evolved to tap into consumer social needs such as belongingness as part of marketing and communications. This chapter describes the cycle that brands enter when they begin to create polarising branded content, the consumer response and the threats inherent in the brand takeover of social discontent.

The HERA experiments, H1 and ZEUS, have measured inclusive neutral current cross sections in e^±p deep inelastic interactions with longitudinally polarised lepton beams. These data are used for investigation of the interference of weak and electromagnetic interactions at high four-momentum transfer squared, Q². Measurements of the interference structure function , which is sensitive to the valence quark distributions, and of the polarised cross section asymmetries are presented. For the first time at HERA, the measurements of H1 and ZEUS are combined in order to improve the statistical precision at high Q². The combined data provide the most accurate measurement of at HERA and lead to the first observation of parity violation in neutral current e^±p scattering at distances down to 10^-18 m. The measurements are compared to predictions of the Standard Model which is able to provide a good description of the data.

Optical phenomena visible to everyone have been central to the development of, and abundantly illustrate, important concepts in science and mathematics. The phenomena considered from this viewpoint are rainbows, sparkling reflections on water, mirages, green flashes, earthlight on the moon, glories, daylight, crystals and the squint moon. And the concepts involved include refraction, caustics (focal singularities of ray optics), wave interference, numerical experiments, mathematical asymptotics, dispersion, complex angular momentum (Regge poles), polarisation singularities, Hamilton’s conical intersections of eigenvalues (‘Dirac points’), geometric phases and visual illusions.

Longitudinal polarisation of the lepton beam is a key ingredient in the success of the world's unique e^±p ring collider HERA. This article aims at providing a brief introduction to the physics motivation for deep-inelastic scattering of polarised electrons or positrons off protons, the basic mechanisms to establish lepton polarisation in the high-energy storage ring and to describe briefly the three different polarimeters, which measured both the transverse and the longitudinal polarisation.

Polarised X-rays are generated from different astrophysical processes, like synchrotron emission and Compton scattering. Polarisation is, therefore, a powerful probe of the emission mechanisms acting in the astrophysical object and its geometry because it gives complementary information with respect to the source spectrum. As of today there have been few missions dedicated to the detection of X-ray polarization leaving this field almost unexplored. PoGOLite is a balloon-borne Compton scattering polarimeter operating in the 20-100 keV energy band. The design and performance of the PoGOLite instrument will be described, together with the in flight performance recorded during the 2013 flight from the Esrange Space Centre.