High-energy unitarity of gravitation and strings

Muzinich, I. J.; Soldate, M.

doi:10.1103/physrevd.37.359

Cited by 143 publications

(208 citation statements)

References 17 publications

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“…Nonetheless, the leading and next-to-leading terms in the large impact parameter expansion for arbitrary p can be computed and read 8) in perfect agreement with the string calculations in eq. (3.10).…”

Section: Classical Deflection Up To Next-to-leading Ordermentioning

confidence: 50%

“…As we lower the impact parameter to study these two new regions, we should be able to make contact with the analysis of high-energy amplitudes at fixed angle as discussed in [9] and, in the context of D-branes, in [53,54]. Moreover, in these regimes the decomposition of the amplitude in partial waves should provide a very useful tool to clarify the main features of the scattering process, as discussed in [8,46,47].…”

Section: Discussionmentioning

confidence: 99%

“…As the energy increases the approximation of single-reggeon exchange eventually breaks down and the tree-level amplitude violates unitarity. As it is well-known both in field theory [38,39] and in string theory [1,2,8], unitarity is recovered by taking into account multi-reggeon exchanges, described in our case by diagrams with a higher number of boundaries. Let us consider now the amplitude with two boundaries, the second term in the perturbative series in eq.…”

Section: Disk and Annulus Amplitudesmentioning

confidence: 99%

“…(3.6) can be made more precise by performing a partial wave decomposition and by rewriting the amplitude in terms of the conserved quantities E and J. In the case of the high-energy string-string interaction this approach was discussed in [8,46,47] and it should be possible to adapt their derivation to the string-brane scattering analyzed in this paper.…”

Section: Classical Deflection Up To Next-to-leading Ordermentioning

confidence: 99%

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High-energy string-brane scattering: leading eikonal and beyond

D’Appollonio

Vecchia

Russo

et al. 2010

J. High Energ. Phys.

122

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We extend previous techniques for calculations of transplanckian-energy stringstring collisions to the high-energy scattering of massless closed strings from a stack of N Dp-branes in Minkowski spacetime. We show that an effective non-trivial metric emerges from the string scattering amplitudes by comparing them against the semiclassical dynamics of high-energy strings in the extremal p-brane background. By changing the energy, impact parameter and effective open string coupling λ = gN , we are able to explore various interesting regimes and to reproduce classical expectations, including tidal-force excitations, even beyond the leading-eikonal approximation.

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Section: Classical Deflection Up To Next-to-leading Ordermentioning

confidence: 50%

Section: Discussionmentioning

confidence: 99%

Section: Disk and Annulus Amplitudesmentioning

confidence: 99%

Section: Classical Deflection Up To Next-to-leading Ordermentioning

confidence: 99%

See 2 more Smart Citations

High-energy string-brane scattering: leading eikonal and beyond

D’Appollonio

Vecchia

Russo

et al. 2010

J. High Energ. Phys.

122

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“…First, such strong growth would eventually violate the unitarity bound once E ∼ M D , indicating that a fuller string calculation is required at higher energies, where the emission and exchange of string states is no longer negligible [101][102][103][104][105][106][107][108]. Second, it shows that it is the highest energy KK states that dominate in the cross section, and since these also have the shortest wavelength their properties (and the cross section) is largely insensitive to the details of the higher-dimensional geometry [109].…”

Section: Jhep10(2011)119mentioning

confidence: 99%

Anisotropic modulus stabilisation: strings at LHC scales with micron-sized extra dimensions

Cicoli

Burgess

Quevedo

2011

J. High Energ. Phys.

151

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We construct flux-stabilised Type IIB string compactifications whose extra dimensions have very different sizes, and use these to describe several types of vacua with a TeV string scale. Because we can access regimes where two dimensions are hierarchically larger than the other four, we find examples where two dimensions are micron-sized while the other four are at the weak scale in addition to more standard examples with all six extra dimensions equally large. Besides providing ultraviolet completeness, the phenomenology of these models is richer than vanilla large-dimensional models in several generic ways: (i) they are supersymmetric, with supersymmetry broken at sub-eV scales in the bulk but only nonlinearly realised in the Standard Model sector, leading to no MSSM superpartners for ordinary particles and many more bulk missing-energy channels, as in supersymmetric large extra dimensions (SLED); (ii) small cycles in the more complicated extra-dimensional geometry allow some KK states to reside at TeV scales even if all six extra dimensions are nominally much larger; (iii) a rich spectrum of string and KK states at TeV scales; and (iv) an equally rich spectrum of very light moduli exist having unusually small (but technically natural) masses, with potentially interesting implications for cosmology and astrophysics that nonetheless evade new-force constraints. The hierarchy problem is solved in these models because the extra-dimensional volume is naturally stabilised at exponentially large values: the extra dimensions are Calabi-Yau geometries with a 4D K3 or T 4 -fibration over a Open Access doi:10.1007/JHEP10 (2011)119 JHEP10 (2011)119 2D base, with moduli stabilised within the well-established LARGE-Volume scenario. The new technical step is the use of poly-instanton corrections to the superpotential (which, unlike for simpler models, are likely to be present on K3 or T 4 -fibered Calabi-Yau compactifications) to obtain a large hierarchy between the sizes of different dimensions. For several scenarios we identify the low-energy spectrum and briefly discuss some of their astrophysical, cosmological and phenomenological implications.

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Time‐dependent orbifolds and string cosmology

Cornalba

Costa

2004

Fortschritte der Physik

149

205

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In these lectures, we review the physics of time-dependent orbifolds of string theory, with particular attention to orbifolds of three-dimensional Minkowski space. We discuss the propagation of free particles in the orbifold geometries, together with their interactions. We address the issue of stability of these string vacua and the difficulties in defining a consistent perturbation theory, pointing to possible solutions. In particular, it is shown that resumming part of the perturbative expansion gives finite amplitudes.Finally we discuss the duality of some orbifold models with the physics of orientifold planes, and we describe cosmological models based on the dynamics of these orientifolds.

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High-energy unitarity of gravitation and strings

Cited by 143 publications

References 17 publications

High-energy string-brane scattering: leading eikonal and beyond

High-energy string-brane scattering: leading eikonal and beyond

Anisotropic modulus stabilisation: strings at LHC scales with micron-sized extra dimensions

Time‐dependent orbifolds and string cosmology

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