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Article
Report number	hep-th/0104173 ; CERN-TH-2001-094 ; CINVESTAV-IPN-25-01 ; CERN-TH-2001-094 ; CINVESTAV-IPN-25-01
Title	The fate of the type I non-BPS D7-brane
Related title	Bogomolny-Prasad-Sommerfield
Author(s)	Loaiza-Brito, Oscar (CERN) ; Uranga, Angel M. (CERN)
Affiliation	(CERN)
Publication	2001
Imprint	20 Apr 2001
Number of pages	25
Note	26 pages, latex, 4 eps figures. v2. Footnote concerning the non-existence of certain 1-brane charges in Section 5 Report-no: CERN-TH/2001-094, CINVESTAV-IPN/25-01
In:	Nucl. Phys. B 619 (2001) 211-231
DOI	10.1016/S0550-3213(01)00505-3
Subject category	Particle Physics - Theory
Abstract	We describe the fate of the Type I non-BPS D7-brane, which is tachyonic but carries a non-trivial K-theory $\IZ_2$ charge. It decays to topologically non-trivial gauge field configurations on the background D9-branes. In the uncompactified theory the decay proceeds to infinity, while with a transverse torus the decay reaches a final state, a toron gauge configuration with vanishing Chern classes but non-trivial $\IZ_2$ charge. A similar behaviour is obtained for the type I non-BPS D8-brane, and other related systems. We construct explicit examples of type IIB orientifolds with non-BPS D7-branes, which are hence non-supersymmetric, but for which supersymmetry is restored upon condensation of the tachyon. We also report on the interesting structure of non-BPS states of type IIA theory in the presence of an O6-plane, their M-theory lifts, the relation between string theory K-theory and M-theory cohomology, and its interplay with NS-NS charged objects. We discuss several new effects, including: i) transmutation between NS-NS and RR torsion charges, ii) non-BPS states classified by K-theory but not by cohomology in string theory, but whose lift to M-theory is cohomological.
Copyright/License	Elsevier Science B.V.

Corresponding record in: Inspire
Email contact: angel.uranga@cern.ch