scholarly journals Moduli stabilisation and the statistics of axion physics in the landscape

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Igor Broeckel ◽  
Michele Cicoli ◽  
Anshuman Maharana ◽  
Kajal Singh ◽  
Kuver Sinha
Keyword(s):  
Decay Constant ◽  
Blow Up ◽  
Closed String ◽  
Effective Field ◽  
Misalignment Angle ◽  
Power Law Distribution ◽  
Independent Case ◽  
Logarithmic Distribution ◽  
Spectrum Feature ◽  
String Landscape

Abstract String theory realisations of the QCD axion are often said to belong to the anthropic window where the decay constant is around the GUT scale and the initial misalignment angle has to be tuned close to zero. In this paper we revisit this statement by studying the statistics of axion physics in the string landscape. We take moduli stabilisation properly into account since the stabilisation of the saxions is crucial to determine the physical properties of the corresponding axionic partners. We focus on the model-independent case of closed string axions in type IIB flux compactifications and find that their decay constants and mass spectrum feature a logarithmic, instead of a power-law, distribution. In the regime where the effective field theory is under control, most of these closed string axions are ultra-light axion-like particles, while axions associated to blow-up modes can naturally play the role of the QCD axion. Hence, the number of type IIB flux vacua with a closed string QCD axion with an intermediate scale decay constant and a natural value of the misalignment angle is only logarithmically suppressed. In a recent paper we found that this correlates also with a logarithmic distribution of the supersymmetry breaking scale, providing the intriguing indication that most, if not all, of the phenomenologically interesting quantities in the string landscape might feature a logarithmic distribution.

scholarly journals Geometry of orientifold vacua and supersymmetry breaking

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Thibaut Coudarchet ◽  
Emilian Dudas ◽  
Hervé Partouche
Keyword(s):  
Field Theory ◽  
Supersymmetry Breaking ◽  
Effective Field Theory ◽  
Scalar Potential ◽  
Open String ◽  
Closed String ◽  
Effective Field ◽  
Internal Space ◽  
Gravitino Mass ◽  
The One

Abstract Starting from a peculiar orientifold projection proposed long ago by Angelantonj and Cardella, we elaborate on a novel perturbative scenario that involves only D-branes, together with the two types of orientifold planes O± and anti-orientifold planes $$ {\overline{\mathrm{O}}}_{\pm } $$ O ¯ ± . We elucidate the microscopic ingredients of such models, connecting them to a novel realization of brane supersymmetry breaking. Depending on the position of the D-branes in the internal space, supersymmetry can be broken at the string scale on branes, or alternatively only at the massive level. The main novelty of this construction is that it features no NS-NS disk tadpoles, while avoiding open-string instabilities. The one-loop potential, which depends on the positions of the D-branes, is minimized for maximally broken, non-linearly realized supersymmetry. The orientifold projection and the effective field theory description reveal a soft breaking of supersymmetry in the closed-string sector. In such models it is possible to decouple the gravitino mass from the value of the scalar potential, while avoiding brane instabilities.

scholarly journals Skyrmions, half-skyrmions and nucleon mass in dense baryonic matter

2014 ◽  
Vol 29 ◽  
pp. 1460238 ◽  
Author(s):  
Yong-Liang Ma ◽  
Masayasu Harada ◽  
Hyun Kyu Lee ◽  
Yongseok Oh ◽  
Mannque Rho
Keyword(s):  
Crucial Role ◽  
Decay Constant ◽  
Effective Field ◽  
Chiral Expansion ◽  
Meson Mass ◽  
Pion Decay ◽  
Baryonic Matter ◽  
Pion Decay Constant ◽  
Effective Lagrangian ◽  
Holographic Qcd

We explore the hadron properties in dense baryonic matter in a unified way by using a Skyrme model constructed with an effective Lagrangian which includes the ρ and ω vector mesons as hidden gauge bosons and is valid up to O(p4) in chiral expansion including the homogeneous Wess-Zumino terms. With the two input values of pion decay constant and the lowest lying vector meson mass which can be fixed in free space, all the other low energy constants in the effective Lagrangian are determined by their master formulas derived from holographic QCD models, which allows us to study the baryonic matter properties with no additional free parameters and thus without ambiguities. We find that the ω field that figures in the homogeneous Wess-Zumino term plays a crucial role in the skyrmion structure and its matter properties. The most striking and intriguing observation is that the pion decay constant that smoothly drops with increasing density in the Skyrmion phase stops decreasing at n1/2 at which the skyrmions in medium fractionize into half-skyrmions and remains nearly constant in the half-skyrmion phase. In accordance with the large Nc consideration, the baryon mass also stays non-scaling in the half-skyrmion phase. This feature is supported by the nuclear effective field theory with the parameters of the Lagrangian scaling modified at the skyrmion–half-skyrmion phase transition. Our exploration also uncovers the crucial role of the ω meson in multi-baryon systems as well as in the structure of a single skyrmion.

scholarly journals Regression to the tail: Why the Olympics blow up

2020 ◽  
pp. 0308518X2095872
Author(s):  
Bent Flyvbjerg ◽  
Alexander Budzier ◽  
Daniel Lunn
Keyword(s):  
Power Law ◽  
Blow Up ◽  
Extreme Event ◽  
Good Practice ◽  
Cost Overrun ◽  
Power Law Distribution ◽  
Tight Coupling ◽  
Mean And Variance ◽  
Generative Mechanism ◽  
The Cost

The Olympic Games are the largest, highest-profile, and most expensive megaevent hosted by cities and nations. Average sports-related costs of hosting are $12.0 billion. Non-sports-related costs are typically several times that. Every Olympics since 1960 has run over budget, at an average of 172 percent in real terms, the highest overrun on record for any type of megaproject. The paper tests theoretical statistical distributions against empirical data for the costs of the Games, in order to explain the cost risks faced by host cities and nations. It is documented, for the first time, that cost and cost overrun for the Games follow a power-law distribution. Olympic costs are subject to infinite mean and variance, with dire consequences for predictability and planning. We name this phenomenon "regression to the tail": it is only a matter of time until a new extreme event occurs, with an overrun larger than the largest so far, and thus more disruptive and less plannable. The generative mechanism for the Olympic power law is identified as strong convexity prompted by six causal drivers: irreversibility, fixed deadlines, the Blank Check Syndrome, tight coupling, long planning horizons, and an Eternal Beginner Syndrome. The power law explains why the Games are so difficult to plan and manage successfully, and why cities and nations should think twice before hosting. Based on the power law, two heuristics are identified for better decision making on hosting. Finally, the paper develops measures for good practice in planning and managing the Games, including how to mitigate the extreme risks of the Olympic power law.

Test Investigation of Velocity Distribution Considering Snow Particles Participating

2010 ◽  
Vol 439-440 ◽  
pp. 1343-1348
Author(s):  
Ke Qin Yan ◽  
Xuan Yi Zhou ◽  
Ming Gu
Keyword(s):  
Wind Tunnel ◽  
Velocity Profile ◽  
Power Law ◽  
Turbulence Intensity ◽  
Wind Tunnel Test ◽  
Test Results ◽  
Power Law Distribution ◽  
Mean Velocity ◽  
Logarithmic Distribution ◽  
Test Investigation

This paper presents the fitting expressions of mean velocity profile and turbulence intensity for wind-snow coupling conditions. Different materials were adopted to simulate the roughness of saltation snow particles to get the distribution of wind velocity in the simple wind tunnel. Test results indicate that velocity profile obeys the logarithmic distribution; the turbulence intensity obeys power law distribution. The influence height of saltation snow particles to the velocity profile limited to 10 cm above from the bed surface.

scholarly journals CLOSED STRING TACHYONS ON C/ZN

2004 ◽  
Vol 19 (32) ◽  
pp. 5625-5638 ◽  
Author(s):  
S. SARKAR ◽  
B. SATHIAPALAN
Keyword(s):  
Point Interaction ◽  
Closed String ◽  
Effective Field ◽  
Quartic Coupling ◽  
Interaction Terms ◽  
Large N ◽  
Quartic Term ◽  
Quartic Interaction ◽  
Interaction Term ◽  
Closed String Tachyons

We analyze the condensation of closed string tachyons on the C/ZN orbifold. We construct the potential for the tachyons up to the quartic interaction term in the large N limit. In this limit there are near marginal tachyons. The quartic coupling for these tachyons is calculated by subtracting from the string theory amplitude for the tachyons, the contributions from the massless exchanges, computed from the effective field theory. We argue that higher point interaction terms are also of the same order in 1/N as the quartic term and are necessary for existence of the minimum of the tachyon potential that is consistent with earlier analysis.

scholarly journals Moduli stabilisation and the statistics of SUSY breaking in the landscape

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Igor Broeckel ◽  
Michele Cicoli ◽  
Anshuman Maharana ◽  
Kajal Singh ◽  
Kuver Sinha
Keyword(s):  
Supersymmetry Breaking ◽  
Power Law ◽  
Complex Structure ◽  
Susy Breaking ◽  
Power Law Distribution ◽  
High Scale ◽  
The Past ◽  
Uniform Distributions ◽  
Logarithmic Distribution ◽  
Breaking Scale

Abstract The statistics of the supersymmetry breaking scale in the string landscape has been extensively studied in the past finding either a power-law behaviour induced by uniform distributions of F-terms or a logarithmic distribution motivated by dynamical supersymmetry breaking. These studies focused mainly on type IIB flux compactifications but did not systematically incorporate the Kähler moduli. In this paper we point out that the inclusion of the Kähler moduli is crucial to understand the distribution of the supersymmetry breaking scale in the landscape since in general one obtains unstable vacua when the F-terms of the dilaton and the complex structure moduli are larger than the F- terms of the Kähler moduli. After taking Kähler moduli stabilisation into account, we find that the distribution of the gravitino mass and the soft terms is power-law only in KKLT and perturbatively stabilised vacua which therefore favour high scale supersymmetry. On the other hand, LVS vacua feature a logarithmic distribution of soft terms and thus a preference for lower scales of supersymmetry breaking. Whether the landscape of type IIB flux vacua predicts a logarithmic or power-law distribution of the supersymmetry breaking scale thus depends on the relative preponderance of LVS and KKLT vacua.

scholarly journals On BPS World Volume, RR Couplings, and Their α′ Corrections in Type IIB

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ehsan Hatefi
Keyword(s):  
Gauge Field ◽  
Correlation Functions ◽  
Closed String ◽  
Effective Field ◽  
Matrix Elements ◽  
Higher Derivative ◽  
World Volume ◽  
S Matrix ◽  
Upper Half Plane ◽  
Algebraic Forms

We compute the asymmetric and symmetric correlation functions of a four-point amplitude of a gauge field, a scalar field, and a closed string Ramond-Ramond (RR) for different nonvanishing BPS branes. All world volume, the Taylor and pull-back couplings, and their all-order α′ corrections have also been explored. Due to various symmetry structures, different restricted BPS Bianchi identities have also been constructed. The prescription of exploring all the corrections of two closed string RR couplings in type IIB is given. We obtain the closed form of the entire S-matrix elements of two closed string RRs and a gauge field on the world volume of BPS branes in type IIB. All the correlation functions of VA0x1VC−1z1,z¯1VC−1z2,z¯2 are also revealed accordingly. The algebraic forms for the most general case of the integrations ∫d2zz−iaz+ibz−z¯cz+z¯d on the upper half plane are derived in terms of Pochhammer and some analytic functions. Lastly, we generate various singularity structures in both effective field theory and IIB string theory, producing different contact interactions as well as their α′ higher derivative corrections.

CONSISTENCY BETWEEN THE S-MATRIX AND THE SIGMA- MODEL APPROACHES TO THE CLOSED STRING EFFECTIVE ACTION ON THE DISC

1988 ◽  
Vol 03 (06) ◽  
pp. 561-569 ◽  
Author(s):  
L.V. ROZHANSKY ◽  
A.A. TSEYTLIN
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Action ◽  
Sigma Model ◽  
Closed String ◽  
Effective Field ◽  
Cosmological Term ◽  
S Matrix ◽  
String Amplitudes ◽  
Closed Bosonic String

We show that a part of logarithmic divergences in the closed bosonic string amplitudes on the disc was over-looked in the previous studies. The sum of all logarithmic divergences is found to be in agreement with the “tadpole” divergences in the effective field theory with the “cosmological term” representing the disc correction. This resolves the problem raised recently by Fischler, Klebanov and Susskind.

scholarly journals Misaligned supersymmetry and open strings

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Niccolò Cribiori ◽  
Susha Parameswaran ◽  
Flavio Tonioni ◽  
Timm Wrase
Keyword(s):  
String Theory ◽  
Energy Levels ◽  
Closed String ◽  
Type Ii ◽  
Open Strings ◽  
String Landscape ◽  
String Theories

Abstract The study of non-supersymmetric string theories is shedding light on an important corner of the string landscape and might ultimately explain why, so far, we did not observe supersymmetry in our universe. We review how misaligned supersymmetry in closed-string theories leads to a cancellation between bosons and fermions even in non-supersymmetric string theories. We then show that the same cancellation takes place for open strings by studying an anti-Dp-brane placed on top of an Op-plane in type II string theory. Misaligned supersymmetry consists in cancellations between bosons and fermions at different energy levels, in such a way that the averaged number of states grows at a rate dominated by a factor $$ {\mathrm{e}}^{C_{\mathrm{e}\mathrm{ff}}\sqrt{n}} $$ e C eff n , with Ceff< Ctot, where Ctot is the inverse Hagedorn temperature. We prove the previously conjectured complete cancellation, i.e. we prove that Ceff = 0, for a vast class of models.

scholarly journals Non-supersymmetric string models from anti-D3-/D7-branes in strongly warped throats

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Susha Parameswaran ◽  
Flavio Tonioni
Keyword(s):  
Model Building ◽  
Open String ◽  
Closed String ◽  
Effective Field ◽  
De Sitter ◽  
Supergravity Theory ◽  
Particle Spectra ◽  
Soft Supersymmetry Breaking ◽  
String Models ◽  
Matter Sector

Abstract This article discusses model-building scenarios including anti-D3-/D7-branes, in which supersymmetry is broken spontaneously, despite having no scale at which sparticles appear and standard supersymmetry is restored. If the branes are placed on singularities at the tip of warped throats in Calabi-Yau orientifold flux compactifications, they may give rise to realistic particle spectra, closed- and open-string moduli stabilisation with a Minkowski/de Sitter uplift, and a geometrical origin for the scale hierarchies. The paper derives the low-energy effective field theory description for such scenarios, i.e. a non-linear supergravity theory for standard and constrained supermultiplets, including soft supersymmetry-breaking matter couplings. The effect of closed-string moduli stabilisation on the open-string matter sector is worked out, incorporating non-perturbative and perturbative effects, and the mass and coupling hierarchies are computed with a view towards phenomenology.

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