Erratum to “Open strings”

Abstract

Abstract. This review is devoted to open strings, and in particular to the often surprising features of their spectra. It follows and summarizes developments that took place mainly at the University of Rome "Tor Vergata" over the last decade, and centred on world-sheet aspects of the constructions now commonly referred to as "orientifolds". Our presentation aims to bridge the gap between the world-sheet analysis, that first exhibited many of the novel features of these systems, and their geometric description in terms of extended objects, D-branes and O-planes, contributed by many other colleagues, and most notably by J. Polchinski. We therefore proceed through a number of prototype examples, starting from the bosonic string and moving on to tendimensional fermionic strings and their toroidal and orbifold compactifications, in an attempt to guide the reader in a self-contained journey to the more recent developments related to the breaking of supersymmetry.

Physics of extra dimensions

“…The discovery limits are about 6 TeV, while the exclusion bounds 15 TeV. An interesting observation in the case of γ (1) + Z (1) is that interferences can lead to a "dip" just before the resonance. There are some ways to distinguish the corresponding signals from other possible origin of new physics, such as models with new gauge bosons.…”

“…3). There are two different channels, neutral Drell-Yan processes pp → l + l − X and the charged channel l ± ν, corresponding to the production of the KK modes γ (1) , Z (1) and W…”

Induced gravity in orientifold models

“…The A, M and K partition functions for the standard Ω orientifolds (that has only D9 branes if N is odd) can e.g. be found in [25] (see also [26] and [27]) and we use the same convention as in [25] that we suppress the winding and momentum sums. The annulus, Moebius and Klein bottle amplitudes for the non-compact ΩJ orientifolds have been presented in [22].…”

Mass hierarchy and physics beyond the Standard Model

“…Unlike in the heterotic string, gauge and gravitational interactions have now different origin. The latter are described again by closed strings, while the former emerge as excitations of open strings with endpoints confined on D-branes [17]. This leads to a braneworld description of our universe, which should be localized on a hypersurface, i.e.…”