11 research outputs found
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 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.