Summary of Standard Model Particlesand Force Interactions

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The Higgs and the Big Bang• At the instant of the Big Bang, the

universe was comprised of particles of pure energy.

• Milliseconds after the event, the universe cooled and the Higgs field developed.

• Particles began to acquire mass as they cooled, slowed down and moved through the newly created Higgs field. Particles lost kinetic energy and gained mass (E=mc2).

• Elementary particles developed and the Higgs field continued to permeate spacetime.

• In unification theory, physicists look to the big bang for evidence of a single superforce. Each of the four fundamental forces is thought of as a manifestation of a single force at low energies.

• Particle accelerators attempt to recreate the original conditions of the Big Bang.

Source: Williams College Astronomy Department

Large Hadron Collider (LHC) From Above

•Cost: up to $10 Billion

•Proton-proton collider

•14 TeV of Energy (7x that of the Tevatron)

•40 million collisions per second

•17 Miles in circumference

•Biggest science project ever constructed

•Most complex machine ever built

Model particle accelerator

Layout

World’s most powerful particle accelerator

Superconducting magnets

– 8.3T at 1.9K

2 beams of protons will collide 40 million times a second

In construction since 1998Due to start later this year

The Large Hadron Collider at CERNThe Large Hadron Collider at CERN

CMS

ATLASLHCb

ALICE

Cross Section of a Particle Detector

Particle Data Group, Lawrence Berkeley National Laboratory

Where is the Higgs?Where is the Higgs?

September …… December 2000

Why do we need the Higgs?Why do we need the Higgs?

Fundamental symmetries of nature require that all the elementary particles and force carriers are massless

in an “ideal” world all elementary particles would be massless

but in the real real world the elementary particles have widely differing masses

so the symmetry must be broken

This is what the Higgs mechanism and electroweak symmetry breaking is all about

Summary – Higgs BosonSummary – Higgs Boson

a lot of questions remain!a lot of questions remain!

• How gravity works?• Black holes problem• Ending of the universe• Many dimension• Solve the string theory• Etc un solved question