Some physicists believe that it may be possible to show thatall fourforces (including gravity) are aspects
of a single underlying force, and covered by a theory called the “Theory of Everything”. Such a theory
(which is essentially a grand unified theory plus gravity) has not yet been found, nor is it known whether
such a theory even exists. Some theories such asstring theoryhave been proposed, but are far from being
experimentally verified. These are issues to be worked out by future generations of physicists.
60.4 The Higgs Boson
A key piece of the Standard Model isHiggs field, which is responsible for giving particles their mass. The
Higgs field fill all of space, even in places where there would otherwise be a vacuum. The degree to which a
particle interacts with the Higgs field determines its mass: particles interacting weakly with the Higgs field
are light, while those that interact strongly with the Higgs field are heavy. Particles that don’t interact with
the Higgs field at all, like the photon, are massless.
The Standard Model predicts that fields that fill all space should be associated with a particle — for
example, as we’ve seen each of the four fundamental forces is associated with a vector boson particle.^2 The
particle associated with the Higgs field is theHiggs boson. The Higgs boson was detected experimentally at
the CERN particle physics accelerator^3 in 2015, thus confirming the existence of the Higgs field and giving
increased confidence in the Standard Model.^4
(^2) Except, perhaps, for gravity.
(^3) CERN stands for Conseil Europ ́een pour la Recherche Nucl ́eaire, and is a facility located on the border between France and Switzer-
land.
(^4) Seehttp://www.nobelprize.org/nobel_prizes/physics/laureates/2013/popular-physicsprize2013.pdf