666 A.G. Quinto et al. / Nuclear Physics B 907 (2016) 664–677
this theory are exhausted by bosons and physical fermions making its gauge sector to have no
on-shell degrees of freedom. These requirements are satisfied by a Chern–Simons-matter theory
called BLG theory [30–34], which describes two M2-branes. Relaxing the requirement of man-
ifest N = 8 supersymmetry, this approach can be generalized to a N = 6
Chern–Simons-matter
theory with the gauge group U
k
(N) × U
−k
(N) (k and −k are CS levels) [35,36], which is ex-
pected to be enhanced to N = 8for k = 1or k = 2 [37–39]. The quantization of such model was
thoroughly studied in [40–48]. Also, detailed calculations of the effective superpotential within
N = 2 superfield theories in three dimension have been reported in [49,50].
The first part of our wo
rk is the computation of the effective superpotential of a generic su-
persymmetric CS theory coupled to matter superfields, up to two-loops. To this end, we use the
RGE and the β and γ function calculated in [17,51], thus avoiding the direct computation of
any supergraph. With this result in hand, we discuss ho
w we can reorganize the expansion of
the effective superpotential in terms of Leading Logs (LL), Next-to-Leading Logs (NLL) con-
tributions, and so on, in a way that allows us to calculate coefficients arising from higher orders
corrections, thus improving the two-loop evaluation of the effective superpotential. We are thus
able to find an i
mproved effective superpotential, which will be used to study DSB in our model.
We will show that, contrary to what happens in the non-supersymmetric case [24], here the RGE
improvement leads only to slight modifications in the DSB scenario.
In this wo
rk, we shall focus on calculations done in the superfield language [52,53], in which
supersymmetry is manifest in all stages of the calculations. This paper is organized as follows:
in Sec. 2, we present our model and calculate the effective superpotential with the knowledge
of the renormalization group functions found in the literature, together with the RGE. Section 3
re
views the standard approach to RGE improvement of the effective potential in four dimensional
models, and section 4 is devoted to adapt this procedure to the supersymmetric three-dimensional
case. The resulting improved effective superpotential is used in Sec. 5 to study DSB in our model.
Section 6 presents our conclusions and perspecti
ves. Some explicit results and the Mathematica
code used to obtain them is given as a Supplementary Material to this work.
2. Calculation of the effective superpotential
Our starting point is the classical action in N = 1 superspace of a Chern–Simons superfield
β
coupled to N massless complex scalars superfields
a
, with a quartic self-interaction,
S =
d
5
z
−
1
2
α
W
α
−
1
2
∇
α
a
∇
α
a
+
λ
4
a
a
2
, (3)
where W
α
=
1
2
D
β
D
α
β
is the gauge superfield strength, ∇
α
=
(
D
α
− ig
α
)
is the gauge su-
percovariant derivative, and a = 1, ... N. We follow the basic conventions for three-dimensional
supersymmetry found in [52].
The main object we shall be interested in studying is the three dimensional effective superpo-
tential [54]. To define this object, we consider a shift in the N-th component of
a
,
N
=
q
N
+ σ, (4)
by the background (constant) superfield σ = σ
1
− θ
2
σ
2
. On general grounds, the effective super-
potential can be cast as
[
σ
]
=
d
5
zK
(
σ
)
+
d
5
zF
σ, D
α
σ, D
2
σ
. (5)