Skip to main content Accessibility help
Internet Explorer 11 is being discontinued by Microsoft in August 2021. If you have difficulties viewing the site on Internet Explorer 11 we recommend using a different browser such as Microsoft Edge, Google Chrome, Apple Safari or Mozilla Firefox.

Chapter 21: String theory and particle physics

Chapter 21: String theory and particle physics

pp. 451-494

Authors

, Massachusetts Institute of Technology
Resources available Unlock the full potential of this textbook with additional resources. There are free resources available for this textbook. Explore resources
  • Add bookmark
  • Cite
  • Share

Summary

Configurations of intersecting D6-branes in type IIA superstring theory define string models of particle physics. Open string states supported at the intersection of the branes naturally give chiral fermions, a key ingredient of the Standard Model. If orientifold planes are included, the models can display the massless spectrum of gauge bosons and chiral fermions of the Standard Model. Compactification moduli are adjustable parameters that give rise to undesirable massless scalars and must be stabilized. Flux compactifications achieve moduli stabilization and give rise to an extremely large landscape of string vacua. The existence of vacua in which the vacuum energy matches the presently observed value becomes statistically plausible.

Intersecting D6-branes

In this section we consider a D-brane configuration that has a set of features that make it a good starting point for the construction of a string model of particle physics. Since we need fermions, we use a ten-dimensional superstring theory. In this theory, six of the ten dimensions, x4, …, x9, are taken to form a small compact space of finite volume. This is necessary in order to have an effectively four-dimensional spacetime (with coordinates x0, x1, x2, and x3). The compact space is as simple as possible: each dimension is turned into a circle, so that the resulting space is a six-dimensional torus T6.

About the book

Access options

Review the options below to login to check your access.

Purchase options

eTextbook
US$84.00
Hardback
US$84.00

Have an access code?

To redeem an access code, please log in with your personal login.

If you believe you should have access to this content, please contact your institutional librarian or consult our FAQ page for further information about accessing our content.

Also available to purchase from these educational ebook suppliers