On non-BPS effective actions of string theory

J. Cosmol. Astropart. Phys.

2019

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In this paper we derive a class of contributions to all orders in α to the effective action of D-braneanti D-brane systems in Type II String Theory, considering an amplitude involving a closed-string Ramond-Ramond state and four open-string states: two tachyons, a scalar and a gauge boson. This type of amplitude arises in both Type IIA and Type IIB strings, and reveals a number of new effective couplings. Furthermore, we derive a series representation for the result that goes beyond a factorized limit that was recently studied, and which is expected to apply to more general six-point amplitudes of superstrings, including external fermions. * Electronic address: riccardo.antonelli@sns.it † Electronic address: ivano.basile@sns.it ‡ Electronic address: ehsan.hatefi@sns.it 1 For in-depth discussions of open strings, see [1]. 2 For earlier detailed treatments, see [2-4]. 3 Similar corrections can also be found in the case of S-branes [7]. 3 are not present. Perturbative scattering amplitudes involve structures that are largely constrained, which makes it possible to reconstruct them, up to an overall coefficient, via Effective Field Theory (EFT) analyses of poles and symmetries in various channels. On the other hand, ab-initio computations of the corresponding string amplitudes have the virtue of fixing the α expansion, and thus the EFT couplings, to all orders. This procedure has been followed systematically in the literature [33-38], yielding generalizations of the standard Dirac-Born-Infeld (DBI), Myers [39] and Wess-Zumino (WZ) terms 4 [40]. The crucial interplay between D-branes and RR potentials has been thoroughly studied in the literature [42], but theirrole is yet to be fully dissected.The paper is organized as follows. In Section 2 we summarize a number of results that were obtained in earlier works, which provides a starting point for our considerations.Specifically, we discuss all-order α corrections to couplings that originate from amplitudes a single closed-string mode and less than four open-string ones. We focus on RR closed-string states, and thus on couplings related to WZ terms. In Section 3 we present the new result on the five-string scattering amplitude under consideration. From the point of view of the (open) world-sheet CFT, this is akin to a six-point correlator, whose vertex operators are to be integrated accordingly. The result is organized in terms of a class of integrals, whose detailed study is postponed to Section 4. In Section 3.3 we briefly discuss a factorized limit in which the integrals can be evaluated in closed form. In sections 3.4 and 3.5, after a proper discussion of bulk singularities, selection rules [43] and EFT methods, we recover the result from the low-energy perspective. In Section 4 we go beyond the factorized limit of Section 3.3, obtaining an expansion for the integrals, whose leading term reproduces it.While the resulting expansion entails a limit of series with decreasing convergence rate, weshow that the procedure is well-defined. We conclude in Section 5 with a su...

Section: Jcap10(2019)041mentioning

confidence: 99%

On all-order higher-point Dp–D̄p̄ effective actions

Antonelli

Basile

J. Cosmol. Astropart. Phys.

2019

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“…The vertex operators of non-BPS D-branes should accompany internal degrees of freedom given the fact that if we send the tachyon to zero, one should recover the WZ action of BPS branes. For more information we recommend the section two of [37] where σ i is Pauli Matrix.…”

Section: Introductionmentioning

confidence: 99%

On special limit of non-supersymmetric effective actions of type II string theory

Vasko

2019

Eur. Phys. J. C

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In this paper we first address four point functions of string amplitudes in both type IIA and IIB string theories. Making use of non-BPS scattering amplitudes, we explore not only several Bianchi identities that hold in both transverse and world volume directions of brane, but also reveal various new couplings. These couplings can just be found by taking into account the mixed pull-back and Taylor couplings where their all order alpha-prime higher derivative corrections have been derived as well.For the first time, we also explore the complete form of a six point non-BPS amplitude, involving three open string tachyons, a scalar field and a Ramond-Ramond closed string in both IIA, IIB. In a special limit of the amplitude and using the proper expansion we obtain an infinite number of bulk singularities that are being constructed in the effective field theory. Finally using new couplings we construct all the other massless and tachyon singularities in type IIA, IIB string theories. All higher derivative corrections to these new couplings to all orders in α ′ and new restricted Bianchi identities have also been gained. 1Recently the generalisation of effective actions of D-brane-anti-D-brane system to all orders in alpha-prime for both Chern-Simons and Dirac-Born-Infeld (DBI) effective actions was discovered [11]. Another example would be related to tachyon condensation that has been investigated in [12] in detail. For D-brane-anti-D-brane system, once the distance between brane and anti-brane becomes smaller than the string length scale, two real tachyonic strings would appear. They are related to strings stretched from D-brane to anti-D-brane and vice versa.Here we would like to deal with N-coincident non-BPS branes and try to embed tachyonic modes and their corrections in EFT. We take non-BPS scattering amplitude formalism as a theoretical framework or laboratory to discover their effective actions, including their all order α ′ corrections in string theory in an efficient and consistent way of matching string results with EFT. To deal with the dynamics of unstable branes, we highlight the recent work done by Polchinski and collaborators [13] where various explanations within

“…Look at[49][50][51][52][53][54][55][56][57][58] to see some of the higher order corrections and to distinguish all order BPS corrections we refer the interested reader in observing[59][60][61][62][63][64][65][66]. To notify all order α corrections to BPS branes one refers to a universal conjecture that is demonstrated in detail in[67], which can also be applied to non-BPS branes where some further ingredients are needed.…”

mentioning

confidence: 99%

All order α′ corrections to fermionic couplings of D-brane-Anti-D-brane effective actions

J. Cosmol. Astropart. Phys.

2019

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We first point out to all order α ′ corrections to lower order fermionic couplings and their effective actions of type II super string theory. In order to reveal all symmetries of the particular D-brane Anti-D-brane system, and to construct not only all the singularity structures but also all order α ′ corrections of fermionic couplings to tachyons, we employ all the Conformal Field Theory (CFT) methods to a six point function. Basically, we construct all the correlation functions of four spin operators and two world sheet fermion fields. The S-matrix of two fermion fields, two real tachyons in the presence of a closed string Ramond-Ramond (RR) field in type II will be explored. Applying all the symmetries of the amplitude, a proper expansion for D-brane Anti D-brane is also found out.Having carried out all the Effective Field Theory (EFT) techniques, one would discover all order singularity structures of string theory. The entire algebraichave also been derived. Various new string couplings are revealed as well. Eventually, making comparison the S-matrix with all EFT parts, all order α ′ higher derivative corrections to two fermions-two tachyons in the world volume of Dbrane Anti D-brane of type II are discovered accordingly. 1