Four loop wave function renormalization in the non-abelian Thirring model

We compute the anomalous dimension of the fermion field with N_f flavours in the fundamental representation of a general Lie colour group in the non-abelian Thirring model at four loops. The implications on the renormalization of the two point Green's function through the loss of multiplicative renormalizability of the model in dimensional regularization due to the appearance of evanescent four fermi operators are considered at length. We observe the appearance of one new colour group Casimir, d_F^{abcd} d_F^{abcd}, in the final four loop result and discuss its consequences for the relation of the Knizhnik-Zamolodchikov critical exponents in the Wess Zumino Witten Novikov model to the non-abelian Thirring model. Renormalization scheme changes are also considered to ensure that the underlying Fierz symmetry broken by dimensional regularization is restored.Comment: 25 latex pages with 9 postscript figure

Anti-counterfeiting: Mixing the Physical and the Digital World

In this paper, we overview a set of desiderata for building digital anti-counterfeiting technologies that rely upon the difficulty of manufacturing randomized complex 3D objects. Then, we observe how this set is addressed by RF-DNA, an anti-counterfeiting technology recently proposed by DeJean and Kirovski. RF-DNA constructs certificates of authenticity as random objects that exhibit substantial uniqueness in the electromagnetic domain

A review of progress in modelling of induced geoelectric and geomagnetic fields with special regard to induced currents

The Earth’s lithosphere and mantle respond to Space Weather through time-varying, depth-dependent induced magnetic and electric fields. Understanding the properties of these electromagnetic fields is a key consideration in modelling the hazard to technological systems from Space Weather. In this paper we review current understanding of these fields, in terms of regional and global-scale geology and geophysics. We highlight progress towards integrated European-scale models of geomagnetic and geoelectric fields, specifically for the purposes of modelling geomagnetically induced currents in power grids and pipelines

Δr in the Two-Higgs-Doublet Model at full one loop level—and beyond

After the recent discovery of a Higgs-like boson particle at the CERN LHC-collider, it becomes more necessary than ever to prepare ourselves for identifying its standard or non-standard nature. The Electroweak parameter Delta r relating the values of the gauge boson masses [MW,MZ] and the Fermi constant [G_F] is the traditional observable encoding high precision information of the electroweak physics at the quantum level. In this work we present a complete quantitative study of Delta r in the framework of the general (unconstrained) Two-Higgs-Doublet Model (2HDM). First of all we report on a systematic analysis of Delta r at the full one loop level in the general 2HDM, which to our knowledge was missing in the literature. Thereby we extract a theoretical prediction for the mass of the W-boson in this model, taking MZ, \alpha_{em} and G_F as experimental inputs. We find typical corrections leading to mass shifts $\delta MW \sim 20-40 MeV$ which help to improve the agreement with the experimentally measured value, in a degree no less significant than in the MSSM case. In the second part of our study we extend our calculation beyond the mere one-loop order. We devise an effective Lagrangian approach that captures the dominant higher order quantum effects on delta rho (viz. that part of Delta r describing the breaking of the approximate SU(2) custodial symmetry) in the limit of large Higgs boson self-interactions. This limit constitutes a telltale property of the general 2HDM which is unmatched by e.g. the MSSM. Our conclusion is that the Electroweak precision program to be conducted at the LHC, and maybe at a future linear collider, can nicely complement the direct searches. Should these distinctive loop effects be eventually found they would signal a smoking gun hinting at non-standard Higgs physics.Comment: LaTeX, 12 figures, 4 tables. Extended discussion, references added. Version accepted in Eur. Phys. J.