Physics Letters B 797 (2019) 134801
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
RG equations and high energy behaviour in non-renormalizable
theories
D.I. Kazakov
a,b,∗
a
Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Russia
b
Moscow Institute of Physics and Technology, Dolgoprudny, Russia
a r t i c l e i n f o a b s t r a c t
Article history:
Received
8 May 2019
Received
in revised form 18 July 2019
Accepted
22 July 2019
Available
online 24 July 2019
Editor:
M. Cveti
ˇ
c
Keywords:
Renormalization
UV
divergences
Non-renormalizable
interactions
We suggest a novel view on non-renormalizable interactions. It is based on the usual BPHZ R-operation
which is equally applicable to any local QFT independently of whether it is renormalizable or not. As
a playground we take the φ
4
D
theory in D dimensions for D = 4, 6, 8, 10 and consider the four-point
scattering amplitude on shell. We derive the generalized RG equation and find the solution valid for any
D that sums up the leading logarithms in all orders of PT in full analogy with the renormalizable case.
It is found that the scattering amplitude in the φ
4
D
theory possesses the Landau pole at high energy for
any D. We discuss the application of the proposed procedure to other non-renormalizable theories.
© 2019 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP
3
.
1. Introduction
The Standard Model is based on renormalizable interactions.
This was a matter of special concern and may serve as a selection
criterion when looking for extensions of the SM. The reason is, as
is well known, that non-renormalizable interactions suffer from UV
divergences and cannot be treated in a usual renormalization fash-
ion
since they require an infinite number of new types of counter
terms. The other drawback is that the amplitudes in such theo-
ries
increase with energy in each order of PT and one cannot sum
them up, like in renormalizable theories, due to the absence of the
proper formalism.
Here
we suggest a novel view on non-renormalizable theories,
namely, we apply the renormalization procedure advocated in our
earlier paper [1], where it was shown that one can renormalize the
theory in a usual way assuming that the renormalization constant
Z serves as an operator that depends on kinematics. This is the
new and essential feature of the renormalization procedure which
gives the UV finite amplitudes. Based on the BPHZ R-operation,
which is equally applicable in this case, one can derive the gen-
eralized
RG equations for the scattering amplitude that sum up
the leading divergences (asymptotics) in all orders of PT. After this,
one can address the question of high energy behaviour of the am-
*
Correspondence to: Bogoliubov Laboratory of Theoretical Physics, Joint Institute
for Nuclear Research, Dubna, Russia.
E-mail
address: kazakovd@theor.jinr.ru.
plitude. It is different for different theories just like in the renor-
malizable
case and can be deduced from the one loop diagrams (in
the renormalizable case it is the one loop beta-function).
In
our previous papers [2–4]we chose as a playground for our
analysis the planar scattering amplitudes in D = 8super Yang-
Mills
theory considered within the spinor helicity formalism [5].
There were some reasons for that. Here we demonstrate the key
points of our procedure on a simple example of the scattering am-
plitudes
in the φ
4
D
theory in D-dimensions, where D = 4, 6, 8, 10.
All these theories are treated in the same unified manner. It is
shown that they all have similar UV behaviour possessing the Lan-
dau
pole at high energy.
2. Bogoliubov R-operation and local counter terms
Any local QFT has the property that in higher orders of PT after
subtraction of divergent subgraphs, i.e. after performing the incom-
plete
R-operation, the so-called R
-operation, the remaining UV
divergences are local functions in the coordinate space or at max-
imum
are polynomials of external momenta in momentum space.
This follows from the rigorous proof of the Bogoliubov-Parasiuk-
Hepp-Zimmermann
R-operation [6] and is equally valid in non-
renormalizable
theories as well.
This
property allows one to construct the so-called recurrence
relations which relate the divergent contributions in all orders of
perturbation theory (PT) with the lower order ones. In renormaliz-
able
theories these relations are known as pole equations (within
dimensional regularization) and are governed by the renormaliza-
https://doi.org/10.1016/j.physletb.2019.134801
0370-2693/
© 2019 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by
SCOAP
3
.