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1 Particle Physics Chris Parkes & Rick StDenis Part 1 Review: Fundamental forces and particles Feynman diagrams Experimental QCD Accelerators and Detectors.

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Presentation on theme: "1 Particle Physics Chris Parkes & Rick StDenis Part 1 Review: Fundamental forces and particles Feynman diagrams Experimental QCD Accelerators and Detectors."— Presentation transcript:

1 1 Particle Physics Chris Parkes & Rick StDenis Part 1 Review: Fundamental forces and particles Feynman diagrams Experimental QCD Accelerators and Detectors Electroweak Theory Part 2 Experimental Electroweak Higgs searches Top Quark Heavy Flavour physics Neutrinos Beyond the Standard Model

2 2 Fundamental Particles & Forces Standard Model Fermions & Bosons Standard Model Structure Common Mesons & Baryons Natural units Revision of

3 3 Particle Physics Aim: Understand the fundamental particles and forces of nature. Tools: Particle colliders operating at the highest energies achievable. It involves the biggest, most complicated experiments in the history of science, with the fastest computers, the coldest temperatures and the strongest magnets on Earth. Particle physics re-creates the universe just after the Big Bang and hopes to answer the questions that humans have been asking for eternity; “Where do we come from?” “What are we made of?”

4 4 CERN 27 km long tunnel,100m underground French/Swiss Border near Geneva 2007 onwards Large Hadron Collider (LHC), 14 TeV proton collider Some alternative reasons to study this course! 2. I want to understand why 5000 physicist worldwide are currently building the world’s largest machine! 1. I want a nobel prize! Origin of mass (Higgs Boson) New Physics (e.g. Supersymmetry) Matter anti-matter asymmetry in Universe (CP Violation) 2 PhD places in Glasgow for Oct – QCD2002 – neutrinos 1999 – QFT tau / neutrino particle detectors Deep Inelastic Scattering muon neutrino W&Z bosons

5 5 Standard Model – Particle Physics Summarises the current knowledge Quantum theory that includes : –unified theory of weak and electromagnetic (QED) interactions (ElectroWeak) –Strong Interactions (Quantum chromodynamics – QCD) –Does not include gravity –Includes one boson – the Higgs – which has not yet been discovered….

6 6

7 7 + Higgs boson, spin 0, electric charge 0, mass unknown yet…..

8 8 Strength – see section on running coupling constants later

9 9 Composite particles Mesons are quark anti-quark system Integer spin particles About 140 types are known Baryons are three quark / three anti-quark systems About 120 types are known Details of all known at Some common ones on the next pages Or where the quarks hide….

10 10 Mesons ParticleSymbol Anti- particle Makeup Rest mass MeV/c 2 Lifetime (s) Decay Modes Pion π+π+ π-π- udud x10 -8 μ+νμμ+νμ Pion π0π0 Self x γ Kaon K+K+ K-K- usus x10 -8 μ + ν μ, π + π 0 Kaon K0sK0s K0sK0s susu x π + π -,2π 0 Kaon K0LK0L K0LK0L susu x10 -8 π+e-νeπ+e-νe Rho ρ0ρ0 Selfuu, dd x π+π-π+π- Phi φ Selfs x K + K -,K 0 K 0 Light Flavour Mesons

11 11 Mesons ParticleSymbol Anti- particle Makeup Rest mass MeV/c 2 LifetimeDecay Modes D D+D+ D-D- cdcd x K + _, e + _ D D0D0 D0D0 cucu x [K,μ,e] + _ D D+sD+s D-sD-s cscs x K + _ J/Psi J/ψ Selfc x e + e -, μ + μ -... B B-B- B+B+ bubu x D 0 + _ B B0B0 B0B0 dbdb x D 0 + _ BsBs Bs0Bs0 Bs0Bs0 sbsb D - s + _ Upsilon ϒ Selfb x e + e -, μ + μ -..

12 12 Table of Baryons ParticleSymbolMakeup Rest mass MeV/c 2 Spin Lifetime (seconds) Decay Modes Proton p uud938.31/2Stable... Neutron n ddu939.61/2920pe - ν e Lambda Λ0Λ0 uds /2 2.6 x pπ -, nπ 0 Sigma Σ+Σ+ uus /2 0.8 x pπ 0, nπ + Sigma Σ0Σ0 uds /26x Λ0γΛ0γ Sigma Σ-Σ- dds /2 1.5 x nπ - Delta Δ ++ uuu12323/2 0.6 x pπ + Delta Δ+Δ+ uud12323/2 0.6 x pπ 0 Baryons -1

13 13 ParticleSymbolMakeup Rest mass MeV/c 2 Spin Lifetime (seconds) Decay Modes Delta Δ0Δ0 udd12323/2 0.6 x nπ 0 Delta Δ-Δ- ddd12323/2 0.6 x nπ - Xi Cascade Ξ0Ξ0 uss13151/2 2.9 x Λ0π0Λ0π0 Xi Cascade Ξ-Ξ- dss13211/ x Λ0π-Λ0π- Omega Ω-Ω- sss16723/ x Ξ 0 π -, Λ 0 K - Lambda Λ+cΛ+c udc22811/22x Baryons -2

14 14 Natural Units,  =c=1 Energy GeV Momentum GeV/c (abbreviated to GeV) Mass GeV/c 2 Length (GeV/  c) -1  c=0.197GeVfm=1 [1fm=1E-15m] –Natural unit of length 1GeV -1 =0.197fm Time (GeV/  ) -1  =6.6E-25GeVs –Natural unit of time 1GeV -1 =6.6E-25s Cross-section (GeV/  c) -2 1barn= m 2 –Natural unit of xsec =1GeV -2 =0.389mb Charge - ‘Heavyside-Lorenz units’ ε 0 =1 Use dimensionless ‘fine structure constant’


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