Life at the Interface of Particle Physics and String Theory

Abstract

If the results of the first LHC run are not betraying us, many decades of particle physics are culminating in a complete and consistent theory for all non-gravitational physics: the Standard Model. But despite this monumental achievement there is a clear sense of disappointment: many questions remain unanswered. Remarkably, most unanswered questions could just be environmental, and disturbingly (to some) the existence of life may depend on that environment. Meanwhile there has been increasing evidence that the seemingly ideal candidate for answering these questions, String Theory, gives an answer few people initially expected: a huge "landscape" of possibilities, that can be realized in a multiverse and populated by eternal inflation. At the interface of "bottom-up" and "top-down" physics, a discussion of anthropic arguments becomes unavoidable. We review developments in this area, focusing especially on the last decade.

59 pages, 5 figures. Invited contribution to Reviews of Modern Physics (original submission date 25 March 2013). Extended version available at http://www.nikhef.nl/~t58/Site/RMP v2: References added, a few typos corrected. v3: Hyperlinks enabled, tex source made paperscape-proof, a few typos corrected. v4: Journal info added, no changes in manuscript

References in corpus (140)

• Four-dimensional String Compactifications with D-Branes, Orientifolds and Fluxes
• Flux Compactification
• The Anthropic Landscape of String Theory
• Nuclear Force from Lattice QCD
• The String Landscape and the Swampland
• The Well-Tempered Neutralino
• Spacetime Instanton Corrections in 4D String Vacua - The Seesaw Mechanism for D-Brane Models
• GUTs and Exceptional Branes in F-theory - II: Experimental Predictions
• A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope
• Eternal inflation and its implications
• Environmental Dependence of Masses and Coupling Constants
• A Mini-Landscape of Exact MSSM Spectra in Heterotic Orbifolds
• Neutrino Majorana Masses from String Theory Instanton Effects
• The Probable Fate of the Standard Model
• Lectures on F-theory compactifications and model building
• Stringy Instantons and Quiver Gauge Theories
• Les Houches Lectures on Constructing String Vacua
• De Sitter Vacua from Matter Superpotentials
• The Heterotic Road to the MSSM with R parity
• Inflationary Constraints on Type IIA String Theory
• Moduli Stabilisation versus Chirality for MSSM like Type IIB Orientifolds
• Sinks in the Landscape, Boltzmann Brains, and the Cosmological Constant Problem
• Heterotic GUT and Standard Model Vacua from simply connected Calabi-Yau Manifolds
• An M Theory Solution to the Strong CP Problem and Constraints on the Axiverse
• Holographic probabilities in eternal inflation
• TASI Lectures on the Cosmological Constant
• Orientifolds, hypercharge embeddings and the Standard Model
• Instanton Induced Neutrino Majorana Masses in CFT Orientifolds with MSSM-like spectra
• The Cosmological Constant and the String Landscape
• Update of axion CDM energy density
• Physics of String Flux Compactifications
• Gauge Coupling Unification in F-theory GUT Models
• Computational complexity of the landscape I
• Stringy Instantons at Orbifold Singularities
• Living Dangerously with Low-Energy Supersymmetry
• Why the Standard Model
• Computation of D-brane instanton induced superpotential couplings - Majorana masses from string theory
• Statistics on the Heterotic Landscape: Gauge Groups and Cosmological Constants of Four-Dimensional Heterotic Strings
• Explaining the Electroweak Scale and Stabilizing Moduli in M Theory
• Resilience of the Spectral Standard Model
• Predicting the Cosmological Constant from the Causal Entropic Principle
• alpha-alpha Scattering in Halo Effective Field Theory
• Thermal derivation of the Coleman-De Luccia tunneling prescription
• Predicting the cosmological constant with the scale-factor cutoff measure
• Inflation, dark matter and dark energy in the string landscape
• Properties of the scale factor measure
• Towards observable signatures of other bubble universes
• Chiral family classification of fermionic Z2xZ2 heterotic orbifold models
• Is Our Universe Likely to Decay within 20 Billion Years?
• Statistical analysis of the supersymmetry breaking scale
• Towards Realistic String Vacua From Branes At Singularities
• Strong-Isospin Violation in the Neutron-Proton Mass Difference from Fully-Dynamical Lattice QCD and PQQCD
• Domain walls, near-BPS bubbles, and probabilities in the landscape
• Dependence of nuclear binding on hadronic mass variation
• An M theory Solution to the Hierarchy Problem
• Are We Typical?
• Populating the Landscape: A Top Down Approach
• Evidence for the Multiverse in the Standard Model and Beyond
• Classification of Heterotic Pati-Salam Models
• From strings to the MSSM
• Boltzmann babies in the proper time measure
• Prediction and explanation in the multiverse
• Stars In Other Universes: Stellar structure with different fundamental constants
• Compactified String Theories -- Generic Predictions for Particle Physics
• Constraints on the variability of quark masses from nuclear binding
• Multiverse Understanding of Cosmological Coincidences
• Entangled black holes as ciphers of hidden information
• Seesaw Neutrinos from the Heterotic String
• Supersymmetry versus Gauge Symmetry on the Heterotic Landscape
• The Minimal Quiver Standard Model
• Stabilizing Moduli with a Positive Cosmological Constant in Heterotic M-Theory
• Stabilizing All Kahler Moduli in Type IIB Orientifolds
• Exploring a string-like landscape
• Puzzles of Anthropic Reasoning Resolved Using Full Non-indexical Conditioning
• Anthropic Distribution for Cosmological Constant and Primordial Density Perturbations
• Testing anthropic predictions for Lambda and the CMB temperature
• A geometric solution to the coincidence problem, and the size of the landscape as the origin of hierarchy
• A Model of Anthropic Reasoning, Addressing the Dark to Ordinary Matter Coincidence
• On mass hierarchies in orientifold vacua
• A Finite Landscape?
• Landscape Predictions for the Higgs Boson and Top Quark Masses
• Nuclear Force from Lattice QCD
• Rapid Tunneling and Percolation in the Landscape
• Graceful exit from a stringy landscape via MSSM inflation
• Hawking-Moss bounces and vacuum decay rates
• Confronting Finite Unified Theories with Low-Energy Phenomenology
• Anthropic tuning of the weak scale and of m_u/m_d in two-Higgs-doublet models
• Cosmological Avatars of the Landscape II: CMB and LSS Signatures
• Fighting the Floating Correlations: Expectations and Complications in Extracting Statistical Correlations from the String Theory Landscape
• Nuclear Astrophysics of Worlds in the String Landscape
• A New View of the Cosmic Landscape
• The Seesaw with Many Right-Handed Neutrinos
• The Landscape "avant la lettre"
• Calabi-Yau Manifolds with Large Volume Vacua
• Random Polynomials and the Friendly Landscape
• Why anthropic reasoning cannot predict Lambda
• The status of cosmological natural selection
• Statistical Understanding of Quark and Lepton Masses in Gaussian Landscapes
• Supersymmetric QCD and noncommutative geometry
• Moduli stabilization and SUSY breaking in heterotic orbifold string models
• Islands in the landscape
• The scale of gravity and the cosmological constant within a landscape
• Updated Axion CDM energy density
• Conifolds and Tunneling in the String Landscape
• The Top 10^{500} Reasons Not to Believe in the Landscape
• On cosmic natural selection
• Quark and Lepton Masses from Gaussian Landscapes
• Metastable String Vacua
• Probabilities in the landscape
• The Cosmological Constant Problem and Inflation in the String Landscape
• Leptogenesis With Many Neutrinos
• Big Bang Nucleosynthesis: The Strong Nuclear Force meets the Weak Anthropic Principle
• Non-supersymmetric Orientifolds of Gepner Models
• Anthropics and Myopics: Conditional Probabilities and the Cosmological Constant
• An Observational Test for the Anthropic Origin of the Cosmological Constant
• Observing other universe through ringholes and Klein-bottle holes
• Permutation orbifolds of heterotic Gepner models
• The Physical Principle that determines the Value of the Cosmological Constant
• Eternal Inflation, Global Time Cutoff Measures, and a Probability Paradox
• The Cosmological Constant and Lorentz Invariance of the Vacuum State
• Deforming, revolving and resolving - New paths in the string theory landscape
• Lifetime of Stringy de Sitter Vacua
• Fractal-Flows and Time's Arrow
• Safety of Minkowski Vacuum
• An argument that the dark matter is axions
• On horizons and the cosmic landscape
• Are there Boltzmann brains in the vacuum
• Variants of the Standard Model with Electroweak-Singlet Quarks
• Asymmetric Gepner Models III. B-L Lifting
• String Phenomenology and the Cosmological Constant
• Why do we observe a weak force? The hierarchy problem in the multiverse
• Was There a Beginning?
• Is Eternal Inflation Past-Eternal? And What if It Is?
• Constraints on $N_c$ in Extensions of the Standard Model
• Anthropic Reasoning in Cosmology: A Historical Perspective
• Towards a non-anthropic solution to the cosmological constant problem
• Will the LHC Look into the Fate of the Universe?
• Flavor Beyond the Standard Universe
• Anthropic Argument for Three Generations
• Tritium as an Anthropic Probe

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• Open string multi-branched and Kahler potentials
• Search for a drifting proton--electron mass ratio from H${}_2$
• The Degree of Fine-Tuning in our Universe -- and Others
• Vacuum Selection from Cosmology on Networks of String Geometries
• The long and winding road from chiral effective Lagrangians to nuclear structure
• Anthropic considerations in nuclear physics
• Two Notions of Naturalness
• On D-brane moduli stabilisation
• Yukawa hierarchies at the point of $E_8$ in F-theory
• Producing the Deuteron in Stars: Anthropic Limits on Fundamental Constants
• The Multiverse and Particle Physics
• $\theta$-dependence of light nuclei and nucleosynthesis
• A new tool in nuclear physics: Nuclear lattice simulations
• Constraints on Alternate Universes: Stars and habitable planets with different fundamental constants
• Gravity and axions from a random UV QFT
• Anthropic Bounds on Lambda from the No-Boundary Quantum State
• Galaxy Formation Efficiency and the Multiverse Explanation of the Cosmological Constant with EAGLE Simulations
• Lepton Flavour Violation in Composite Higgs Models
• Superparticle phenomenology from the natural mini-landscape
• Top quark mass coupling and classification of weakly-coupled heterotic superstring vacua
• On the Habitability of Universes without Stable Deuterium
• D6-Brane Model Building on Z(2)xZ(6): MSSM-like and Left-Right Symmetric Models
• The Spectra of Type IIB Flux Compactifications at Large Complex Structure
• On self-gravitating strange dark matter halos around galaxies
• Alpha-alpha scattering in the Multiverse
• Sensitivity of Carbon and Oxygen Yields to the Triple-Alpha Resonance in Massive Stars
• Viscosity and diffusion in life processes and tuning of fundamental constants
• Multiverse Predictions for Habitability: The Number of Stars and their Properties
• Stellar Helium Burning in Other Universes: A solution to the triple alpha fine-tuning problem
• Why trust a theory? Some further remarks (part 1)
• Multiverse Predictions for Habitability: Number of Potentially Habitable Planets
• The Fine Structure Constant and Habitable Planets
• GUTs without guts
• Multiverse Predictions for Habitability: Planetary Characteristics
• Anthropics of Aluminum-26 Decay and Biological Homochirality
• Non-collider searches for stable massive particles
• Effects of Bound Diprotons and Enhanced Nuclear Reaction Rates on Stellar Evolution
• Phenomenology of A Little Higgs Pseudo-Axion
• Probing nuclear observables via primordial nucleosynthesis
• Complexity and the Big Bang
• Entanglement in Markovian hybrid classical-quantum theories of gravity
• D = 1 supergravity and quantum cosmology
• Multiverse Predictions for Habitability: Stellar and Atmospheric Habitability
• The weak-gravity bound and the need for spin in asymptotically safe matter-gravity models
• Massless Spectra and Gauge Couplings at One-Loop on Non-Factorisable Toroidal Orientifolds
• Improved Constraints on the Variation of the Weak Scale from Big Bang Nucleosynthesis
• Physics Beyond the Multiverse - Naturalness and the Quest for a Fundamental Theory
• Multiverse Predictions for Habitability: Origin of Life Scenarios
• Lectures on Naturalness, String Landscape and Multiverse
• Anthropic Origin of the Neutrino Mass from Cooling Failure
• Possible Solution to the Triple Alpha Fine-Tuning Problem: Spallation Reactions during Planet Formation
• Fundamental physical constants, operation of physical phenomena and entropy increase
• The Fine-Tuning Argument
• High Performance Algorithms for Quantum Gravity and Cosmology
• Naturalness as a reasonable scientific principle in fundamental physics
• The exoplanets analogy to the Multiverse