The Experts below are selected from a list of 4266 Experts worldwide ranked by ideXlab platform
Mohammad Reza Garousi - One of the best experts on this subject based on the ideXlab platform.
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s matrix elements and covariant tachyon action in type 0 theory
Nuclear Physics, 2005Co-Authors: Mohammad Reza GarousiAbstract:Abstract We evaluate the sphere level S-matrix element of two Tachyons and two massless NS states, the S-matrix element of four Tachyons, and the S-matrix element of two Tachyons and two Ramond–Ramond vertex operators, in type 0 theory. We then find an expansion for theses amplitudes that their leading order terms correspond to a covariant tachyon action. To the order considered, there are no T 4 , T 2 ( ∂ T ) 2 , T 2 H 2 , nor T 2 R tachyon couplings, whereas, the tachyon couplings F F ¯ T and T 2 F 2 are non-zero.
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off shell extension of s matrix elements and tachyonic effective actions
Journal of High Energy Physics, 2003Co-Authors: Mohammad Reza GarousiAbstract:We show that the on-shell S-matrix elements of four open string massless scalars, two scalars and two Tachyons, and four open string Tachyons in the super string theory can be written in a unique form. We then propose an off-shell extension for the S-matrix element of four scalars which is consistent, in the low energy limit, with the Dirac-Born-Infeld effective action. Using a similar off-shell extension for the S-matrix element of two scalars and two Tachyons and for the S-matrix element of four Tachyons, we show that they are fully consistent with the tachyonic DBI action.
Shinji Hirano - One of the best experts on this subject based on the ideXlab platform.
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the cap in the hat unoriented 2d strings and matrix vector models
Journal of High Energy Physics, 2004Co-Authors: Oren Bergman, Shinji HiranoAbstract:We classify the possible bosonic and type 0 unoriented open and closed string theories in two dimensions, and find their dual matrix(-vector) models. There are no RP2 R-R tadpoles in any of the models, but many of them possess a massless tachyon tadpole. Thus all the models we find are consistent two-dimensional string vacua, but some get quantum corrections to their classical tachyon background. Where possible, we solve the tadpole cancellation condition, and find all the tachyon tadpole-free theories.
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the cap in the hat unoriented 2d strings and matrix vector models
arXiv: High Energy Physics - Theory, 2003Co-Authors: Oren Bergman, Shinji HiranoAbstract:We classify the possible bosonic and Type 0 unoriented string theories in two dimensions, and find their dual matrix(-vector) models. There are no RP^2 R-R tadpoles in any of the models, but many of them possess a massless tachyon tadpole. Thus all the models we find are consistent two-dimensional string vacua, but some get quantum corrections to their classical tachyon background. Where possible, we solve the tadpole cancellation condition, and find all the tachyon tadpole-free theories.
Oren Bergman - One of the best experts on this subject based on the ideXlab platform.
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the cap in the hat unoriented 2d strings and matrix vector models
Journal of High Energy Physics, 2004Co-Authors: Oren Bergman, Shinji HiranoAbstract:We classify the possible bosonic and type 0 unoriented open and closed string theories in two dimensions, and find their dual matrix(-vector) models. There are no RP2 R-R tadpoles in any of the models, but many of them possess a massless tachyon tadpole. Thus all the models we find are consistent two-dimensional string vacua, but some get quantum corrections to their classical tachyon background. Where possible, we solve the tadpole cancellation condition, and find all the tachyon tadpole-free theories.
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the cap in the hat unoriented 2d strings and matrix vector models
arXiv: High Energy Physics - Theory, 2003Co-Authors: Oren Bergman, Shinji HiranoAbstract:We classify the possible bosonic and Type 0 unoriented string theories in two dimensions, and find their dual matrix(-vector) models. There are no RP^2 R-R tadpoles in any of the models, but many of them possess a massless tachyon tadpole. Thus all the models we find are consistent two-dimensional string vacua, but some get quantum corrections to their classical tachyon background. Where possible, we solve the tadpole cancellation condition, and find all the tachyon tadpole-free theories.
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a non supersymmetric open string theory and s duality
arXiv: High Energy Physics - Theory, 1997Co-Authors: Oren Bergman, Matthias R GaberdielAbstract:A non-supersymmetric ten-dimensional open string theory is constructed as an orbifold of type I string theory, and as an orientifold of the bosonic type B theory. It is purely bosonic, and cancellation of massless tadpoles requires the gauge group to be SO(32)xSO(32). The spectrum of the theory contains a closed string tachyon, and open string Tachyons in the (32,32) multiplet. The D-branes of this theory are analyzed, and it is found that the massless excitations of one of the 1-branes coincide with the world-sheet degrees of freedom of the D=26 bosonic string theory compactified on the SO(32) lattice. This suggests that the two theories are related by S-duality.
Paolo Di Vecchia - One of the best experts on this subject based on the ideXlab platform.
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multiloop soft theorem for gravitons and dilatons in the bosonic string
Journal of High Energy Physics, 2019Co-Authors: Paolo Di Vecchia, Raffaele Marotta, Matin MojazaAbstract:We construct, in the closed bosonic string, the multiloop amplitude involving N Tachyons and one massless particle with 26 - D compactified directions, and we show that at least for D > 4, the s ...
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Multiloop soft theorem for gravitons and dilatons in the bosonic string
'Springer Science and Business Media LLC', 2019Co-Authors: Paolo Di Vecchia, Raffaele Marotta, Matin MojazaAbstract:Abstract We construct, in the closed bosonic string, the multiloop amplitude involving N Tachyons and one massless particle with 26 − D compactified directions, and we show that at least for D > 4, the soft behaviors of the graviton and dilaton satisfy the same soft theorems as at the tree level, up to one additional term at the subsubleading order, which can only contribute to the dilaton soft behavior and which we show is zero at least at one loop. This is possible, since the infrared divergences due to the non-vanishing tachyon and dilaton tadpoles do not depend on the number of external particles and are therefore the same both in the amplitude with the soft particle and in the amplitude without the soft particle. Therefore this leaves unchanged the soft operator acting on the amplitude without the soft particle. The additional infrared divergence appearing for D ≤ 4 depend on the number of external legs and must be understood on their own
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multiloop soft theorem for gravitons and dilatons in the bosonic string
arXiv: High Energy Physics - Theory, 2018Co-Authors: Paolo Di Vecchia, Raffaele Marotta, Matin MojazaAbstract:We construct, in the closed bosonic string, the multiloop amplitude involving $N$ Tachyons and one massless particle with $26 -D$ compactified directions, and we show that at least for $D>4$, the soft behaviors of the graviton and dilaton satisfy the same soft theorems as at the tree level, up to one additional term at the subsubleading order, which can only contribute to the dilaton soft behavior and which we show is zero at least at one loop. This is possible, since the infrared divergences due to the non-vanishing tachyon and dilaton tadpoles do not depend on the number of external particles and are therefore the same both in the amplitude with the soft particle and in the amplitude without the soft particle. Therefore this leaves unchanged the soft operator acting on the amplitude without the soft particle. The additional infrared divergence appearing for $D \leq 4$ depend on the number of external legs and must be understood on their own.
Matin Mojaza - One of the best experts on this subject based on the ideXlab platform.
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multiloop soft theorem for gravitons and dilatons in the bosonic string
Journal of High Energy Physics, 2019Co-Authors: Paolo Di Vecchia, Raffaele Marotta, Matin MojazaAbstract:We construct, in the closed bosonic string, the multiloop amplitude involving N Tachyons and one massless particle with 26 - D compactified directions, and we show that at least for D > 4, the s ...
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Multiloop soft theorem for gravitons and dilatons in the bosonic string
'Springer Science and Business Media LLC', 2019Co-Authors: Paolo Di Vecchia, Raffaele Marotta, Matin MojazaAbstract:Abstract We construct, in the closed bosonic string, the multiloop amplitude involving N Tachyons and one massless particle with 26 − D compactified directions, and we show that at least for D > 4, the soft behaviors of the graviton and dilaton satisfy the same soft theorems as at the tree level, up to one additional term at the subsubleading order, which can only contribute to the dilaton soft behavior and which we show is zero at least at one loop. This is possible, since the infrared divergences due to the non-vanishing tachyon and dilaton tadpoles do not depend on the number of external particles and are therefore the same both in the amplitude with the soft particle and in the amplitude without the soft particle. Therefore this leaves unchanged the soft operator acting on the amplitude without the soft particle. The additional infrared divergence appearing for D ≤ 4 depend on the number of external legs and must be understood on their own
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multiloop soft theorem for gravitons and dilatons in the bosonic string
arXiv: High Energy Physics - Theory, 2018Co-Authors: Paolo Di Vecchia, Raffaele Marotta, Matin MojazaAbstract:We construct, in the closed bosonic string, the multiloop amplitude involving $N$ Tachyons and one massless particle with $26 -D$ compactified directions, and we show that at least for $D>4$, the soft behaviors of the graviton and dilaton satisfy the same soft theorems as at the tree level, up to one additional term at the subsubleading order, which can only contribute to the dilaton soft behavior and which we show is zero at least at one loop. This is possible, since the infrared divergences due to the non-vanishing tachyon and dilaton tadpoles do not depend on the number of external particles and are therefore the same both in the amplitude with the soft particle and in the amplitude without the soft particle. Therefore this leaves unchanged the soft operator acting on the amplitude without the soft particle. The additional infrared divergence appearing for $D \leq 4$ depend on the number of external legs and must be understood on their own.