Higgs-regularized three-loop four-gluon amplitude in N=4 SYM: exponentiation and Regge limits

We compute the three-loop contribution to the N=4 supersymmetric Yang-Mills planar four-gluon amplitude using the recently-proposed Higgs IR regulator of Alday, Henn, Plefka, and Schuster. In particular, we test the proposed exponential ansatz for the four-gluon amplitude that is the analog of the BDS ansatz in dimensional regularization. By evaluating our results at a number of kinematic points, and also in several kinematic limits, we establish the validity of this ansatz at the three-loop level. We also examine the Regge limit of the planar four-gluon amplitude using several different IR regulators: dimensional regularization, Higgs regularization, and a cutoff regularization. In the latter two schemes, it is shown that the leading logarithmic (LL) behavior of the amplitudes, and therefore the lowest-order approximation to the gluon Regge trajectory, can be correctly obtained from the ladder approximation of the sum of diagrams. In dimensional regularization, on the other hand, there is no single dominant set of diagrams in the LL approximation. We also compute the NLL and NNLL behavior of the L-loop ladder diagram using Higgs regularization.Comment: 45 pages, 9 figures; v3: major revision (more stringent tests, discussion of order of limits in the Regge regime

Pulled in and pushed out of politics: the impact of neoliberalism on young people's differing political consumerist motivations in the UK and Greece

Political consumerism refers to citizens’ use of boycotting and buycotting as they seek to influence political outcomes within the marketplace rather than through more traditional routes such as voting. However, given the pressure that neoliberalist forces exert on the marketplace, the lack of literature problematising the relationship between political consumerism and neoliberalism is somewhat surprising. Addressing this gap, we examine how neoliberalism impacts youth political consumerism in the UK and Greece. Focus-group findings suggest the existence of two inter-connected effects. Firstly, we detect a neoliberal ‘push effect’ away from electoral politics. Secondly, we discern a parallel ‘pull effect’ as young people seek the ‘political’ within the marketplace. In Greece, youth political consumerism seems to result primarily from distrust of institutional political actors. In contrast, young political consumers in the UK appear to be principally driven by confidence in the capacity of the market to respond to their pressing needs