Warped Passages - Lisa Randall [225]
All of the models that address the hierarchy problem have visible weak-scale consequences. The signatures of the warped geometry that addresses the hierarchy problem are particularly amazing. If this theory is right, we will detect KK particles and measure their properties from the clues they leave behind. If, instead, other extra-dimensional models describe the universe, energy will disappear into extra dimensions and we’ll ultimately detect those dimensions through the resulting unbalanced energy accounting.
We certainly don’t yet know all the answers. But the universe is about to be pried open. Astrophysical observations will explore the cosmos earlier, further away, and in more detail than ever before. Discoveries at the LHC will tell us about the nature of matter at distances smaller than any physical process ever observed. At high energies, truths about the universe should start to explode.
Secrets of the cosmos will begin to unravel. I, for one, can’t wait.
Glossary
action at a distance The hypothetical instantaneous effect of objects on other, distant objects.
aether A hypothesized invisible substance (now debunked) whose vibrations were supposed to be electromagnetic waves.
alpha particle A helium nucleus (consisting of two protons and two neutrons).
anarchic principle The statement that all interactions that are not forbidden by symmetries will occur.
anomaly Symmetry violation that arises from quantum contributions to a physical interaction, but which is not present in the corresponding classical theory (in which quantum contributions are not taken into account).
anomaly-free theory A theory for which the symmetries of the classical theory are also symmetries of the theory with quantum contributions included.
anomaly mediation Communication of supersymmetry breaking by quantum effects.
anthropic principle The reasoning that says, out of many possible universes, we could live only in a place where structure could have formed.
anti de Sitter space Spacetime with constant negative curvature. antiparticle A particle with the same mass as another particle, but opposite charge.
atom A building block of matter consisting of electrons orbiting a positively charged nucleus.
beta decay Radioactive decay in which a neutron splits into a proton, an electron, and a neutrino.
black hole A compact object that is so dense that nothing can escape from its surrounding gravitational field.
blackbody An idealized object that absorbs all heat and energy and radiates it back in a manner determined solely by its temperature.
blackbody radiation Radiation emitted by a blackbody.
boson A particle with integer spin—1, 2, etc. (one of two categories of particle established by quantum mechanics, the other being the fermion); photons and the Higgs particle are examples of bosons.
bottom quark A short-lived, heavier version of the down and strange quarks.
brane A membrane-like object in higher-dimensional space that can carry energy and confine particles and forces.
braneworld A physical setup in which matter and forces are confined to branes.
bulk Full higher-dimensional space.
Calabi-Yau manifold A six-dimensional compact space, defined by its particular mathematical properties, that plays an important role in string theory.
CERN The Conseil Européen pour la Recherche Nucléaire (now called the Organisation Européenne pour la Recherche Nucléaire or, in English, the European Organization for Nuclear Research), a high-energy accelerator facility in Switzerland; future home of the Large Hadron Collider (LHC).
charm quark A short-lived, heavier version of the up quark.
chirality The handedness of a particle with spin.
classical physics Physical laws that takes neither quantum mechanics nor relativity into account.
closed string A string that loops around and has no ends.
collapse of the wavefunction Reduction of the quantum state after a precise measurement fixes the value of the measured quantity.
compact