scholarly journals Dynamical tadpoles, stringy cobordism, and the SM from spontaneous compactification

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Ginevra Buratti ◽  
Matilda Delgado ◽  
Angel M. Uranga
Keyword(s):  
String Theory ◽  
Particle Physics ◽  
String Model ◽  
Distance Scale ◽  
Spontaneous Compactification ◽  
Large Classes ◽  
Finite Distance ◽  
Physics Model ◽  
M Theory

Abstract We consider string theory vacua with tadpoles for dynamical fields and uncover universal features of the resulting spacetime-dependent solutions. We argue that the solutions can extend only a finite distance ∆ away in the spacetime dimensions over which the fields vary, scaling as ∆n∼$$ \mathcal{T} $$ T with the strength of the tadpole $$ \mathcal{T} $$ T . We show that naive singularities arising at this distance scale are physically replaced by ends of spacetime, related to the cobordism defects of the swampland cobordism conjecture and involving stringy ingredients like orientifold planes and branes, or exotic variants thereof. We illustrate these phenomena in large classes of examples, including AdS5×T1,1 with 3-form fluxes, 10d massive IIA, M-theory on K3, the 10d non-supersymmetric USp(32) strings, and type IIB compactifications with 3-form fluxes and/or magnetized D-branes. We also describe a 6d string model whose tadpole triggers spontaneous compactification to a semirealistic 3-family MSSM-like particle physics model.

scholarly journals Geography of fields in extra dimensions: String theory lessons for particle physics

2015 ◽  
Vol 30 (10) ◽  
pp. 1530008 ◽  
Author(s):  
Hans Peter Nilles ◽  
Patrick K. S. Vaudrevange
Keyword(s):  
String Theory ◽  
Particle Physics ◽  
Extra Dimensions ◽  
Model Building ◽  
Unified Theory ◽  
Fundamental Interactions ◽  
Spatial Dimensions ◽  
Physics Model ◽  
String Theories

String theoretical ideas might be relevant for particle physics model building. Ideally one would hope to find a unified theory of all fundamental interactions. There are only a few consistent string theories in D = 10 or 11 spacetime dimensions, but a huge landscape in D = 4. We have to explore this landscape to identify models that describe the known phenomena of particle physics. Properties of compactified six spatial dimensions are crucial in that respect. We postulate some useful rules to investigate this landscape and construct realistic models. We identify common properties of the successful models and formulate lessons for further model building.

scholarly journals STATUS OF SUPERSTRING AND M-THEORY

2010 ◽  
Vol 25 (25) ◽  
pp. 4703-4725 ◽  
Author(s):  
JOHN H. SCHWARZ
Keyword(s):  
String Theory ◽  
Particle Physics ◽  
M Theory ◽  
Viable Model

The first lecture gives a colloquium-level overview of string theory and M-theory. The second lecture surveys various attempts to construct a viable model of particle physics. A recently proposed approach, based on F-theory, is emphasized.

scholarly journals MODELS OF PARTICLE PHYSICS FROM TYPE IIB STRING THEORY AND F-THEORY: A REVIEW

2013 ◽  
Vol 28 (05n06) ◽  
pp. 1330005 ◽  
Author(s):  
ANSHUMAN MAHARANA ◽  
ERAN PALTI
Keyword(s):  
String Theory ◽  
Particle Physics ◽  
Model Building ◽  
Realistic Model ◽  
Theory Model ◽  
Strongly Coupled ◽  
Moduli Stabilization ◽  
Physics Model ◽  
Type Iib String Theory ◽  
Review Model

We review particle physics model building in type IIB string theory and F-theory. This is a region in the landscape where in principle many of the key ingredients required for a realistic model of particle physics can be combined successfully. We begin by reviewing moduli stabilization within this framework and its implications for supersymmetry breaking. We then review model building tools and developments in the weakly coupled type IIB limit, for both local D3-branes at singularities and global models of intersecting D7-branes. Much of recent model building work has been in the strongly coupled regime of F-theory due to the presence of exceptional symmetries which allow for the construction of phenomenologically appealing Grand Unified Theories. We review both local and global F-theory model building starting from the fundamental concepts and tools regarding how the gauge group, matter sector and operators arise, and ranging to detailed phenomenological properties explored in the literature.

scholarly journals The String Theory Landscape

Universe ◽  
2019 ◽  
Vol 5 (7) ◽  
pp. 176 ◽  
Author(s):  
Michael R. Douglas
Keyword(s):  
String Theory ◽  
Cosmological Constant ◽  
Particle Physics ◽  
Cosmological Constant Problem ◽  
Grand Unified Theories ◽  
Eternal Inflation ◽  
The Standard Model ◽  
Unified Theories ◽  
Spatial Dimensions ◽  
M Theory

String/M theory is formulated in 10 and 11 space-time dimensions; in order to describe our universe, we must postulate that six or seven of the spatial dimensions form a small compact manifold. In 1985, Candelas et al. showed that by taking the extra dimensions to be a Calabi–Yau manifold, one could obtain the grand unified theories which had previously been postulated as extensions of the Standard Model of particle physics. Over the years since, many more such compactifications were found. In the early 2000s, progress in nonperturbative string theory enabled computing the approximate effective potential for many compactifications, and it was found that they have metastable local minima with small cosmological constant. Thus, string/M theory appears to have many vacuum configurations which could describe our universe. By combining results on these vacua with a measure factor derived using the theory of eternal inflation, one gets a theoretical framework which realizes earlier ideas about the multiverse, including the anthropic solution to the cosmological constant problem. We review these arguments and some of the criticisms, with their implications for the prediction of low energy supersymmetry and hidden matter sectors, as well as recent work on a variation on eternal inflation theory motivated by computational complexity considerations.

scholarly journals Xenon-1T excess as a possible signal of a sub-GeV hidden sector dark matter

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Amin Aboubrahim ◽  
Michael Klasen ◽  
Pran Nath
Keyword(s):  
Dark Matter ◽  
Particle Physics ◽  
Small Mass ◽  
Big Bang ◽  
Mass Splitting ◽  
Recoil Energy ◽  
Dirac Fermions ◽  
Dark Sector ◽  
Dark Photon ◽  
Physics Model

Abstract We present a particle physics model to explain the observed enhancement in the Xenon-1T data at an electron recoil energy of 2.5 keV. The model is based on a U(1) extension of the Standard Model where the dark sector consists of two essentially mass degenerate Dirac fermions in the sub-GeV region with a small mass splitting interacting with a dark photon. The dark photon is unstable and decays before the big bang nucleosynthesis, which leads to the dark matter constituted of two essentially mass degenerate Dirac fermions. The Xenon-1T excess is computed via the inelastic exothermic scattering of the heavier dark fermion from a bound electron in xenon to the lighter dark fermion producing the observed excess events in the recoil electron energy. The model can be tested with further data from Xenon-1T and in future experiments such as SuperCDMS.

scholarly journals Singular BPS boundary conditions in $$ \mathcal{N} $$ = (2, 2) supersymmetric gauge theories

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Tadashi Okazaki ◽  
Douglas J. Smith
Keyword(s):  
String Theory ◽  
Boundary Conditions ◽  
Gauge Theories ◽  
Holomorphic Curve ◽  
Two Dimensional ◽  
Supersymmetric Gauge Theories ◽  
Special Lagrangian ◽  
Supersymmetric Gauge ◽  
M Theory

Abstract We derive general BPS boundary conditions in two-dimensional $$ \mathcal{N} $$ N = (2, 2) supersymmetric gauge theories. We analyze the solutions of these boundary conditions, and in particular those that allow the bulk fields to have poles at the boundary. We also present the brane configurations for the half- and quarter-BPS boundary conditions of the $$ \mathcal{N} $$ N = (2, 2) supersymmetric gauge theories in terms of branes in Type IIA string theory. We find that both A-type and B-type brane configurations are lifted to M-theory as a system of M2-branes ending on an M5-brane wrapped on a product of a holomorphic curve in ℂ2 with a special Lagrangian 3-cycle in ℂ3.

scholarly journals The “Emerging” Reality from “Hidden” Spaces

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 75
Author(s):  
Richard Pincak ◽  
Alexander Pigazzini ◽  
Saeid Jafari ◽  
Cenap Ozel
Keyword(s):  
Dark Matter ◽  
String Theory ◽  
Topological Approach ◽  
New Approach ◽  
Topological Interpretation ◽  
New Interpretation ◽  
M Theory

The main purpose of this paper is to show and introduce some new interpretative aspects of the concept of “emergent space” as geometric/topological approach in the cosmological field. We will present some possible applications of this theory, among which the possibility of considering a non-orientable wormhole, but mainly we provide a topological interpretation, using this new approach, to M-Theory and String Theory in 10 dimensions. Further, we present some conclusions which this new interpretation suggests, and also some remarks considering a unifying approach between strings and dark matter. The approach shown in the paper considers that reality, as it appears to us, can be the “emerging” part of a more complex hidden structure. Pacs numbers: 11.25.Yb; 11.25.-w; 02.40.Ky; 02.40.-k; 04.50.-h; 95.35.+d.

scholarly journals 5d and 4d SCFTs: canonical singularities, trinions and S-dualities

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Cyril Closset ◽  
Simone Giacomelli ◽  
Sakura Schäfer-Nameki ◽  
Yi-Nan Wang
Keyword(s):  
String Theory ◽  
Field Theories ◽  
Flavor Symmetry ◽  
Crepant Resolution ◽  
Superconformal Field Theories ◽  
Hypersurface Singularities ◽  
Canonical Singularities ◽  
Type Iib String Theory ◽  
M Theory

Abstract Canonical threefold singularities in M-theory and Type IIB string theory give rise to superconformal field theories (SCFTs) in 5d and 4d, respectively. In this paper, we study canonical hypersurface singularities whose resolutions contain residual terminal singularities and/or 3-cycles. We focus on a certain class of ‘trinion’ singularities which exhibit these properties. In Type IIB, they give rise to 4d $$ \mathcal{N} $$ N = 2 SCFTs that we call $$ {D}_p^b $$ D p b (G)-trinions, which are marginal gaugings of three SCFTs with G flavor symmetry. In order to understand the 5d physics of these trinion singularities in M-theory, we reduce these 4d and 5d SCFTs to 3d $$ \mathcal{N} $$ N = 4 theories, thus determining the electric and magnetic quivers (or, more generally, quiverines). In M-theory, residual terminal singularities give rise to free sectors of massless hypermultiplets, which often are discretely gauged. These free sectors appear as ‘ugly’ components of the magnetic quiver of the 5d SCFT. The 3-cycles in the crepant resolution also give rise to free hypermultiplets, but their physics is more subtle, and their presence renders the magnetic quiver ‘bad’. We propose a way to redeem the badness of these quivers using a class $$ \mathcal{S} $$ S realization. We also discover new S-dualities between different $$ {D}_p^b $$ D p b (G)-trinions. For instance, a certain E8 gauging of the E8 Minahan-Nemeschansky theory is S-dual to an E8-shaped Lagrangian quiver SCFT.

No-scale supergravity inflation: A bridge between string theory and particle physics?

2016 ◽  
Vol 25 (14) ◽  
pp. 1630027 ◽  
Author(s):  
John Ellis
Keyword(s):  
Supergravity Models ◽  
String Theory ◽  
Effective Potential ◽  
Particle Physics ◽  
Model Building ◽  
Inflationary Model ◽  
New Wave ◽  
Microwave Background ◽  
Supergravity Theory ◽  
Text Model

The plethora of recent and forthcoming data on the cosmic microwave background (CMB) data are stimulating a new wave of inflationary model-building. Naturalness suggests that the appropriate framework for models of inflation is supersymmetry. This should be combined with gravity in a supergravity theory, whose specific no-scale version has much to commend it, e.g. its derivation from string theory and the flat directions in its effective potential. Simple no-scale supergravity models yield predictions similar to those of the Starobinsky [Formula: see text] model, though some string-motivated versions make alternative predictions. Data are beginning to provide interesting constraints on the rate of inflaton decay into Standard Model particles. In parallel, LHC and other data provide significant constraints on no-scale supergravity models, which suggest that some sparticles might have masses close to present experimental limits.

scholarly journals The Fayet-Iliopoulos term in Type-I string theory and M-theory

1998 ◽  
Vol 437 (3-4) ◽  
pp. 318-324 ◽  
Author(s):  
John March-Russell
Keyword(s):  
String Theory ◽  
Type I ◽  
M Theory
Sign in / Sign up

Export Citation Format

Share Document