Eur. Phys. J. C (2016) 76:391
DOI 10.1140/epjc/s10052-016-4213-7
Regular Article - Theoretical Physics
Comments on interactions in the SUSY models
Sudhaker Upadhyay
1,a
, Alexander Reshetnyak
2,b
, Bhabani Prasad Mandal
1,c
1
Department of Physics, Banaras Hindu University, Varanasi 221005, India
2
Institute of Strength Physics and Materials Science of SB RAS, Tomsk 634021, Russia
Received: 2 November 2015 / Accepted: 16 June 2016 / Published online: 12 July 2016
© The Author(s) 2016. This article is published with open access at Springerlink.com
Abstract We consider special supersymmetry (SUSY)
transformations with m generators
←−
s
α
, for some class of
models and study the physical consequences when mak-
ing the Grassmann-odd transformations to form an Abelian
supergroup with finite parameters and a set of group-like
elements with finite parameters being functionals of the field
variables. The SUSY-invariant path integral measure within
conventional quantization scheme leads to the appearance of
the Jacobian under a change of variables generated by such
SUSY transformations, which is explicitly calculated. The
Jacobian implies, first of all, the appearance of trivial interac-
tions in the transformed action, and, second, the presence of
a modified Ward identity which reduces to the standard Ward
identities in the case of constant parameters. We examine the
case of the N = 1 and N = 2 supersymmetric harmonic
oscillators to illustrate the general concept by a simple free
model with (1, 1) physical degrees of freedom. It is shown
that the interaction terms U
tr
have a corresponding SUSY-
exact form: U
tr
=
V
(1)
←−
s ; V
(2)
←−
¯s
←−
s
generated naturally
under such generalized formulation. We argue that the case
of a non-trivial interaction cannot be obtained in such a way.
1 Introduction
Supersymmetric theories are invariant under SUSY transfor-
mations which relate the bosonic and fermionic degrees of
freedom present in the theories and were proposed initially
with the motivation of studying the fundamental interactions
in a unified manner. The generators of SUSY transforma-
tions satisfy the Lie superalgebra relations, which are closed
under a combination of the commutators and anticommu-
tators. The local or non-linear versions of Lie superalgebra
constructions have been extended to various field-theoretic
a
e-mail: sudhakerupadhyay@gmail.com
b
e-mail: reshet@ispms.tsc.ru
c
e-mail: bhabani.mandal@gmail.com
models such as superstring theories [1], supergravity [2,3]
(for modern developments see Refs. [4,5]) and higher-spin
field theories [6–11]. SUSY theory provides a bosonic super-
partner to each fermion presented in the theory and vice versa.
This indicates whether N = 1 (with one fermionic generator
in terms of Dirac spinor) SUSY has to be a perfect symme-
try of nature; then each set of superpartners must have the
same set of quantum numbers with as the only difference
the spin. Despite the beauty of all these unified theories, the
SUSY theory has not been supported by experimental evi-
dence so far, but it remains one of the problems of the LHC
experimental program.
Some variants of SUSY have also become interesting top-
ics in quantum mechanics [12] due to the link to exactly solv-
able models. SUSY and its breaking have been studied in var-
ious simple quantum mechanical systems involving a spin-
1/2 particle moving in one direction [13,14]. The supersym-
metric Hamiltonian may be presented in terms of the super-
charges which generate the SUSY transformations. A path
integral formulation of SUSY in quantum mechanics was
first analyzed by Salomonson and van Holten [15]. Further,
by using SUSY methods, the tunneling rate through quantum
mechanical barriers was accurately determined [16–19].
The SUSY transformations, when applied for the gauge
theory together with special global SUSY transformations,
known as BRST transformations [20–22], have also been
explored in a more effective way [23,24]. The BRST sym-
metry and the associated concept of BRST cohomology pro-
vide the commonly used quantization methods in Lagrangian
[25,26] and Hamiltonian [27,28] formalisms for the gauge
and string theories [29,30]. The BRST symmetry was gen-
eralized [26] to the case of an infinitesimal field-dependent
(FD) transformation parameter μ, μ
2
= 0, within the field–
antifield formalism [25,26]in[26], in order to prove the inde-
pendence from small gauge variations of the path integral
for arbitrary gauge theory. A further generalization [31]was
made in Yang-Mills theories with R
ξ
-gauges by making the
transformation parameter finite and field-dependent, as one
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