2,966 research outputs found
Supersymmetric Sudakov corrections
For superpartner masses not much heavier than the weak scale ,
large logarithmic corrections of the Sudakov type arise at TeV energies. In
this paper we discuss the general structure of electroweak supersymmetric
(susy) Sudakov corrections in the framework of the infrared evolution equation
method. We discuss Yukawa sector Ward-identities which lead to the
exponentiation of the subleading (SL) logarithmic Yukawa enhanced Sudakov
corrections in both the Standard Model (SM) as well as in softly broken
supersymmetric extensions. The results are given to SL accuracy to all orders
in perturbation theory for arbitrary external lines in the ``light'' susy-mass
scenario. The susy-QCD limit for virtual corrections is presented.
Phenomenological applications regarding the precise determination of the
important parameter through virtual corrections are discussed
which are independent of the soft susy breaking mechanism to sub-subleading
accuracy to all orders.Comment: 5 pages, 2 figures, contribution to RADCOR02/Loops and Legs 200
Mass gap effects and higher order electroweak Sudakov logarithms
The infrared structure of spontaneously broken gauge theories is
phenomenologically very important and theoretically a challenging problem.
Various attempts have been made to calculate the higher order behavior of large
double-logarithmic (DL) corrections originating from the exchange of
electroweak gauge bosons resulting in contradictory claims. We present results
from two loop electroweak corrections for the process to DL accuracy. This process is ideally suited as a
theoretical model reaction to study the effect of the mass gap of the neutral
electroweak gauge bosons at the two loop level. Contrary to recent claims in
the literature, we find that the calculation performed with the physical
Standard Model fields is in perfect agreement with the results from the
infrared evolution equation method. In particular, we can confirm the
exponentiation of the electroweak Sudakov logarithms through two loops.Comment: 10 pages, 3 figures, LaTeX2e, uses epsfi
Resummation of angular dependent corrections in spontaneously broken gauge theories
Recent investigations of electroweak radiative corrections have revealed the
importance of higher order contributions in high energy processes, where the
size of typical corrections can exceed those associated with QCD considerably.
Beyond one loop, only universal (angular independent) corrections are known to
all orders except for massless
processes where also angular dependent corrections exist in the literature. In
this paper we present general arguments for the consistent resummation of
angular dependent subleading (SL) logarithmic corrections to all orders in the
regime where all invariants are still large compared to the gauge boson masses.
We discuss soft isospin correlations, fermion mass and gauge boson mass gap
effects, the longitudinal and Higgs boson sector as well as mixing
contributions including CKM effects for massive quarks. Two loop arguments are
interpreted in the context of the effective high energy effective theory based
on the Standard Model Lagrangian in the symmetric basis with the appropriate
matching conditions to include the soft QED regime. The result is expressed in
exponentiated operator form in a CKM-extended isospin space in the symmetric
basis. Thus, a full electroweak SL treatment based on the infrared evolution
equation method is formulated for arbitrary high energy processes at future
colliders. Comparisons with known results are presented.Comment: 22 pages, 3 eps-figures, uses LaTeX2
Electroweak Sudakov corrections
At energies much larger than the mass of the weak gauge bosons, electroweak
radiative corrections can lead to significant corrections. At 1 TeV the one
loop corrections can be of due to large contributions of the
Sudakov type. We summarize recent progress in the evaluation and resummation of
the double and single logarithmic corrections to general scattering amplitudes
for fermions, transversely as well as longitudinally polarized external lines.Comment: contribution to LCWS2000 at Fermila
- …