2,451 research outputs found
Renormalization Group Treatment of Nonrenormalizable Interactions
The structure of the UV divergencies in higher dimensional nonrenormalizable
theories is analysed. Based on renormalization operation and renormalization
group theory it is shown that even in this case the leading divergencies
(asymptotics) are governed by the one-loop diagrams the number of which,
however, is infinite. Explicit expression for the one-loop counter term in an
arbitrary D-dimensional quantum field theory without derivatives is suggested.
This allows one to sum up the leading asymptotics which are independent of the
arbitrariness in subtraction of higher order operators. Diagrammatic
calculations in a number of scalar models in higher loops are performed to be
in agreement with the above statements. These results do not support the idea
of the na\"ive power-law running of couplings in nonrenormalizable theories and
fail (with one exception) to reveal any simple closed formula for the leading
terms.Comment: LaTex, 11 page
The Mellin moments of deep inelastic structure functions at two loops
We perform the analytic calculation of the Mellin moments of the structure
functions F_2 and F_L in perturbative QCD up to second order corrections and in
leading twist approximation. We calculate the 2-loop contributions to the
anomalous dimensions of the singlet and non-singlet operator matrix elements
and the 2-loop coefficient functions of F_2 and F_L. Our results are in
agreement with earlier calculations in the literature.Comment: 4 pages LaTeX, talk given at the QCD 99 Euroconference, Montpellier
(France
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