PUBLIC UNDERSTANDING OF SCIENCE W. G. SCOTT RAL/PPD 28 Nov 2007 We are encouraged to spend 1% of our research grant funding on “outreach” activities, promoting understanding, appreciation and awareness of our science to the general public: Targeting yr olds in schools etc. can help attract more young people into a scientific career. (e.g. RAL MasterClass Mar 2008). Helps ensure that the UKs front line contribution in this science is recognised by opinion formers, decision-takers/politicians. Taxpayers can have an appreciation and awareness of the research being funded on their behalf. Helps produce highly qualified researchers with advanced skills needed by academia, industry and commerce.
THE STANDARD MODEL: “higgs potential” fermion kinetic term gauge “kinetic” term yukawa term higgs kinetic term where: “covariant derivative” field-strength tensor vector potential (schematic)
THE HIGGS FIELD: gives masses to the pointlike particles : quarks leptons W,Z etc. refraction?.
u=“UP” (+2/3) PROTON NEUTRON d=“DOWN” (-1/3) QUARKS …but not to the neutron/proton!
PARTICLE PHYSICS
THE ATOM neutron NUCLEUS electrons (-) proton (+)
u=“UP” (+2/3) PROTON NEUTRON d=“DOWN” (-1/3) QUARKS
ELECTRICAL FORCES e-e- e-e- Photon QUANTUM FIELD THEORY
QED e- γ
d d γ QED
QUARK CONFINEMENT The “Strong” Force Quark Antiquark
“CHROMOSTATICS”
THE “COLOUR” FORCE
QCD gluons 8 colours quarks 3 colours
THE WEAK FORCE Beta Decay np Antineutrino Electron
BETA DECAY (at the quark level) du Antineutrino Electron
u e- d W+ WEAK INTERACTION
THE WEAK FORCE u e- W+ Due to W-boson exchange
The Discovery of the W +/- and Z 0 UAI (1983) MASSES: W +/- ≈ 80GeV Z 0 ≈ 91GeV
NEUTRAL CURRENTS (1973)
ELECTRO-WEAK
THE “FORCE” PARTICLES g 1 g 2 g 3 g 4 g 5 g 6 g 7 g 8 W - Z 0 W + γ
CERN
THE “MATTER” PARTICLES Q /3 +2/3
THE DISCOVERY OF TOP (Fermilab USA 1994) top ≈ 180 GeV
ELECTROWEAK e-e- e+e+ z0z0 w+w+ w-w-
GAUGE THEORIES
MATTER PARTICLES (Fermions) FORCE PARTICLES (Bosons) = 0 (Pauli exclusion principle) = 4 (Stimulated emission, lasers etc)
PLANCK SCALE 10 GeV 19 GUT SCALE 10 GeV 16 GRAND UNIFICATION: strong weak hyper. INVERSE COUPLING ENERGY GeV
INTERACTION WITH THE HIGGS FIELD gives masses to the “point-like” particles, quarks, leptons, W, Z etc.
PROF HIGGS UNIV EDINBURGH
HIGGS AT LEP
TO DISCOVER THE HIGGS WE NEED: THE LHC
V THE NEUTRINO A VERY FRIENDLY PARTICLE
ATMOSPHERIC NEUTRINOS
SUPER-KAMIOKANDE
MINOS CHICAGOMINESSOTA (750 Km)
CP-VIOLATION
THE FUNDAMENTAL FORCES WEAK STRONGGRAVITY ELECTRO- MAGNETIC UNIFIED FORCE?
1973“Neutral currents” 1983w+/-, z 1996z* → ww RECENT DEVELOPMENTS IN PARTICLE PHYSICS
NEUTRINO MASSES ?? 1)Solar 2)Atmospheric →v 3 ≈ 85 MeV ?
THE DISCOVERY OF TOP (1994) t → b w ev top ≈ 180 GeV
ATMOSPHERIC NEUTRINOS EARTH Cosmic ray (protons) Neutrino Detector