Physics Letters B 785 (2018) 315–319
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Physics Letters B
www.elsevier.com/locate/physletb
BRST approach to Lagrangian construction for bosonic continuous spin
field
I.L. Buchbinder
a,b,c
, V.A. Krykhtin
a,∗
, H. Takata
a
a
Department of Theoretical Physics, Tomsk State Pedagogical University, Kievskaya St. 60, 634061, Tomsk, Russia
b
National Research Tomsk State University, Lenin Av. 36, 634050 Tomsk, Russia
c
Departamento de Física, ICE, Universidade Federal de Juiz de Fora, Campus Universitário, Juiz de Fora, 36036-900, MG, Brazil
a r t i c l e i n f o a b s t r a c t
Article history:
Received
13 June 2018
Accepted
30 July 2018
Available
online 30 August 2018
Editor:
M. Cveti
ˇ
c
We formulate the conditions defining the irreducible continuous spin representation of the four-
dimensional
Poincaré group based on spin-tensor fields with dotted and undotted indices. Such a
formulation simplifies analysis of the Bargmann–Wigner equations and reduces the number of equations
from four to three. Using this formulation we develop the BRST approach and derive the covariant
Lagrangian for the continuous spin fields.
© 2018 The Authors. 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
Description of the irreducible representations of the Poincaré
and AdS groups play important role in the formulation of the
higher spin field models (see e.g. the reviews [1], [2]). One of such
representations is representation with continuous spin.
Continuous
(or infinite) spin representation of the Poincaré
group [3–5]being massless has unusual properties such as an
infinite number of degrees of freedom and appearance of the di-
mensional
parameter μ in the conditions defining the irreducible
representation (see for the review [6]). Lagrangian for the bosonic
field in d = 4was first proposed in ref. [7] and its structure was
analyzed in ref. [8]. Later Lagrangian for bosonic continuous field
was generalized for d > 4 and written in terms of a tower of
double traceless tensor fields in the works [9] and in terms of
two towers of traceless fields in the works [10](see also the
approaches to Lagrangian constriction in the works [11–16]for
bosonic and fermionic fields and relation to the string theory in
[17,18]). Interaction of continuous spin fields with finite spin mas-
sive
fields was considered in the papers [19,20]. Model of rela-
tivistic
particle corresponding to continuous spin field has been
constructed in the recent work [21].
In
the present paper we develop the BRST approach to derive
the Lagrangian for the continuous spin fields in four-dimensional
Minkowski space. This approach is a direct generalization of the
*
Corresponding author.
E-mail
addresses: joseph@tspu.edu.ru (I.L. Buchbinder), krykhtin@tspu.edu.ru
(V.A. Krykhtin),
takata@tspu.edu.ru (H. Takata).
general BRST construction which was used in our works for de-
riving
the Lagrangians for the free fields of different types in flat
and AdS spaces (see e.g. [22–26] and the references therein, see
also the review [27]).
1
The crucial element of our approach is the
implementation of the two-component spinor description for the
continuous spin fields. We suppose that the BRST construction in
terms of spin-tensor fields, considered in the given paper, essen-
tially
simplifies an clarifies the derivation of the Lagrangian and its
analysis.
The
paper is organized as follows. In the next section we con-
sider
a new, in comparison with ref. [3], possibility of realization
for the spin momentum operators in terms of two-component
spinors and obtain new equations for the field realizing the con-
tinuous
spin irreducible representation of the Poincaré group. After
this we solve one of these equations and in section 3 we construct
Lagrangian on the base of the BRST method. Then we show that
after removing one auxiliary field and rescaling the other fields
and the gauge parameter the Lagrangian obtained exactly coincides
with Lagrangian derived by Metsaev [10].
2. Spin-tensor representation
According to Bargmann and Wigner [3], the continuous spin
field are characterized by the following eigenvalues of the Casimir
operators
1
The various applications of the BRST-BFV construction in the continuous spin
field theory have been studied in refs. [9,10,14,15,19,28,29].
https://doi.org/10.1016/j.physletb.2018.07.070
0370-2693/
© 2018 The Authors. 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
.