4,767 research outputs found
Supersymmetric and Kappa-invariant Coincident D0-Branes
We propose a generic supersymmetric and kappa-invariant action for describing
coincident D0-branes with non-abelian matter fields on their worldline. The
action is shown to be in agreement with the Matrix Theory limit of the
ND0-brane effective action.Comment: JHEP style, 1+8 page
More on integrable structures of superstrings in AdS(4) x CP(3) and AdS(2) x S(2) x T(6) superbackgrounds
In this paper we continue the study, initiated in arXiv:1009.3498 and
arXiv:1104.1793, of the classical integrability of Green-Schwarz superstrings
in AdS(4) x CP(3) and AdS(2) x S(2) x T(6) superbackgrounds whose spectrum
contains non-supercoset worldsheet degrees of freedom corresponding to broken
supersymmetries in the bulk. We derive an explicit expression, to all orders in
the coset fermions and to second order in the non-coset fermions, which extends
the supercoset Lax connection in these backgrounds with terms depending on the
non-coset fermions. An important property of the obtained form of the Lax
connection is that it is invariant under Z_4-transformations of the
superisometry generators and the spectral parameter. This demonstrates that the
contribution of the non-coset fermions does not spoil the Z_4-symmetry of the
super-coset Lax connection which is of crucial importance for the application
of Bethe-ansatz techniques. The expressions describing the AdS(4) x CP(3) and
AdS(2) x S(2) x T(6) superstring sigma--models and their Lax connections have a
very similar form. This is because their amount of target-space supersymmetries
complement each other to 32=24+8, the maximal number of 10d type II
supersymmetries. As a byproduct, this similarity has allowed us to obtain the
form of the geometry of the complete type IIA AdS(2) x S(2) x T(6) superspace
to all orders in the coset fermions and to the second order in the non-coset
ones.Comment: 28 pages; v2: References adde
String Amplitudes and Frame-like Formalism for Higher Spins
We analyze open string vertex operators describing connection gauge fields
for spin 3 in Vasiliev's frame-like formalism and perform their extended BRST
analysis. Gauge symmetry transformations, generalized zero torsion constraints
relating extra fields to the dynamical frame-like field and relation between
dynamical frame-like field and fully symmetric Fronsdal's field for spin 3 are
all realized in terms of BRST constraints on these vertex operators in string
theory. Using the construction, we analyze the 3-point correlator for spin 3
field and calculate Chern-Simons type cubic interactions described by
3-derivative Berends-Burgers-van Dam (BBD) type vertex in the frame-like
formalism.Comment: 25 page
On Dimensional Degression in AdS(d)
We analyze the pattern of fields in d+1 dimensional anti-de Sitter space in
terms of those in d dimensional anti-de Sitter space. The procedure, which is
neither dimensional reduction nor dimensional compactification, is called
dimensional degression. The analysis is performed group-theoretically for all
totally symmetric bosonic and fermionic representations of the anti-de Sitter
algebra. The field-theoretical analysis is done for a massive scalar field in
AdS(d+d) and massless spin one-half, spin one, and spin two fields in
AdS(d+1). The mass spectra of the resulting towers of fields in AdS(d) are
found. For the scalar field case, the obtained results extend to the shadow
sector those obtained by Metsaev in [1] by a different method.Comment: 30 page
The degenerate gravitino scenario
In this work, we explore the "degenerate gravitino" scenario where the mass
difference between the gravitino and the lightest MSSM particle is much smaller
than the gravitino mass itself. In this case, the energy released in the decay
of the next to lightest sypersymmetric particle (NLSP) is reduced. Consequently
the cosmological and astrophysical constraints on the gravitino abundance, and
hence on the reheating temperature, become softer than in the usual case. On
the other hand, such small mass splittings generically imply a much longer
lifetime for the NLSP. We find that, in the constrained MSSM (CMSSM), for
neutralino LSP or NLSP, reheating temperatures compatible with thermal
leptogenesis are reached for small splittings of order 10^{-2} GeV. While for
stau NLSP, temperatures of 4x10^9 GeV can be obtained even for splittings of
order of tens of GeVs. This "degenerate gravitino" scenario offers a possible
way out to the gravitino problem for thermal leptogenesis in supersymmetric
theories.Comment: 27 pages, 10 figures and 1 table. Minor typos and references fixed.
Matches published version in JCAP
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