Introduction To Nuclear And Particle Physics
Introduction to Nuclear and Particle PhysicsPHY357Better name is probably Introduction to Subatomic physics:Emphasis is on particle physics; nuclear physics is simply particle physicsat relatively low energy.Course web page http://www.physics.utoronto.ca/ krieger/phys357.htmlCourse outlineAnnouncementsReference materialsGrading SchemeDates for Assignments and TestsOffice HoursPolicies AssignmentsPolicies on Email1
The Subatomic WorldExperimental investigationof smaller and smallerdistance scales requirehigher and higher energies“fundamental” particlesare point-like at the highestexperimentally achievableenergy scale2
The Standard ModelDescribes the FUNDAMENTAL PARTICLES and their INTERACTIONSAll known FORCES are mediated by PARTICLE EXCHANGEaa the (dimensionless) coupling strength at the vertexXαEffective strength of an interaction depends onαa the mass of the exchanged particle MXaForceEffective StrengthPhysical ProcessStrong100Nuclear bindingElectromagnetic10-2Electron-nucleus bindingWeak10-5Radioactiveβdecay3
Fundamental InteractionsStructure of the Standard Model:Electromagnetic Interaction (QED)Weak Interaction}Electroweak TheoryStrong Interaction (QCD)QED Quantum ElectrodynamicsQCD Quantum ChromodynamicsThese models are defined by their particle content of the theory and by theallowed interactions of these particles (i.e. what are the allowed vertices)4
electromagnetic forcestrong forcespin 1/2weak forcespin 1/2spin 15
Number of Light Fermion GenerationsNeed to account for thethree colour states of eachquark when calculating theSM rate for this process.6
The Standard Model of Particle PhysicsFermions( spin ½ )Matter particles µ ν µ L c s L e ν e L u d LγBosons( spin 1 )Force carriers W ,Zg0 τ ν τ L t b Lcharged leptonsneutral leptonsquarksStandard Model predicts the existenceof one fundamental scalar (spin-0)particle known as the Higgs Boson.This is the only particle of the SM thathas yet to be experimentally observed.7
The Standard Model of Particle PhysicsFermions( spin ½ )Matter particles µ ν µ L c s L e ν e L u d LγBosons( spin 1 )Force carriers W ,Zg τ ν τ L t b LQ -1Q 2/3Q -1/3Particles with electromagnetic interactions08
The Standard Model of Particle PhysicsFermions( spin ½ )Matter particles µ ν µ L c s L e ν e L u d L τ ν τ L t b LγBosons( spin 1 )Force carriers W ,Zg0Particles with weak interactions9
The Standard Model of Particle PhysicsFermions( spin ½ )Matter particles µ ν µ L c s L e ν e L u d L τ ν τ L t b LγBosons( spin 1 )Force carriers W ,Zg0Particles with strong interactions10
The Standard Model of Particle PhysicsFermions( spin ½ )Matter particles µ ν µ L c s L e ν e L u d L τ ν τ L t b LFirst observation 2001First observation 1995γBosons( spin 1 )Force carriers W ,Zg011
Feynman Diagrams for Fundamental ProcessesUsed to represent all fundamental interactionsAStable particle (A) in free space (moving or at rest)particle traveling backwards in time anti-particle traveling forwards in timeAStable anti-particle (A) in free space (moving or at rest)NBhere time runs upwards – The choice is merely aconvention and has no other meaning. Often youwill see it left to right.12
Feynman Diagrams for Fundamental ProcessesBXParticle decayAABXtime(assumes MA MB MX)Read this as: at some point in time there is a particle A, and at a laterpoint it decays into particles B and Xor X couples A to Bor X and B and A couple togetherNote that there is no spatial component to these diagrams (thediverging lines do not imply that the particles are flying apart)13
Feynman Diagrams for ScatteringABCombine two vertex primitives tomake lowest order scattering diagramXAA BA BB14
Feynman Diagrams for ScatteringCDif for example, X also couples C to DXA BAC DB15
Feynman Diagrams for ScatteringBDA CXAB DC16
Feynman Diagrams for Scatteringeee e-ge e-(Bhabha scattering)Electromagnetic interactionee17
Feynman Diagrams for Scatteringνeee νeWe νe(electron-neutrino scattering)weak interactioneνe18
Feynman Diagrams for Scatteringνµµe νeµ νµWweak interactioneνe19
Feynman Diagrams for Scatteringude νeudWweak interactioneνe20
Feynman Diagrams for ScatteringduududWweak interactiondu21
Feynman Diagrams for ScatteringscudcsWweak interactiondu22
Feynman Diagrams for Scatteringνµμudµ νµWweak interactiondu23
Feynman Diagrams for ScatteringOften there is more than one diagram contributing to a single processeee e-ge e- (Bhabha scattering)annihilation diagram(s-channel)ee24
Feynman Diagrams for Scatteringegee e-e e- (Bhabha scattering)photon exchange diagramee(t-channel)25
Feynman Diagrams for Scatteringegee- e-e- e- (Moller scattering)photon exchange diagramee(there is no annihilation diagram)26
The Higgs BosonQuantum Electrodynamics can be made to yield finite values for all calculationsElectroweak Theory give infinite result for processes such as W W-WWgWWg WWWWWWWW W- WAmplitude for this process is finite if the Higgs boson is includedWWH0WWHiggs Boson makes W and Z0 massive andis also responsible generating the massesof fundamental particles. It is a quantumfield permeating the Universe27
A Physical AnalogyIn vacuum, a photon has velocity c and mass 0In glass a photon has velocity c which is equivalent to mass 0This is due to the photon interactions with the electromagnetic field incondensed matterBy analogy, we can understand the masses of particles as arising dueto interactions with Higgs field (in vacuum).This Higgs field is an important part of inflationary theories28
Force UnificationsStandard Model does NOT accountfor gravitational icityelectroweakSTANDARDweak interactionsis defined as the energy scale atwhich gravitational interactionsbecome of the same strength asSM interactionsGUTMODELstrong onterrestrialmovementPlanck Scale (or Planck Mass)MEWMGUTMplanckEnergy scale29
YOU ARE HERE !last-scatteringResponsible forCosmic Microwave BackgroundGrand Unification era30
Expansion of the UniverseBIG BANG model came from the observation that the UNIVERSE IS EXPANDINGFor distant galaxies velocity (w.r.t us) distance v H0 x distanceHubble constantWhether the Universe continue to expand or begins at some point tocontract depends upon the density of matter and energy in the Universee.g. is there enough matter and energy in the Universe for the gravitationalattraction to stop (and possible reverse) the Universe’s expansion ?31
The Fate of the UniverseIf ρ0, the density of matter and energy in the Universe, is greater thansome critical density, ρc, the expansion of the Universe will eventuallycease and reverse, so that it ultimately contracts (THE BIG CRUNCH)If ρ0, the density of matter and energy in the Universe, is LESS than thencritical density, ρc, the expansion of the Universe will continue forever(THE BIG FREEZE)Usually measure the density in units of ρcρ0 8π G ρ0Ω0 3 H 02ρCΩ0 1spherical space-time: contractionΩ0 1flat space time: expansion (asymptotic)Ω0 1hyperbolic space-time: expansion32
Measuring Ω0Amazingly, we can measure the total matter/energy density in the Universe !!!Use temperature fluctuations in the cosmic microwave background (CMB)Wilkinson MicrowaveAnisotropy Probe (WMAP)ℓ related to angular scalepeak at 200 evidence for Ω0 133
Density of Standard Model MatterReferred to as Baryonic Matter (eg. made of protons and neutrons)Density is ΩBIf Universe is made of ONLY quarks and leptons ΩB Ω0 1ΩB measured from abundance of elements produced in nucleosynthesisDeuterium, Helium, LithiumΩB 0.05ΩB Ω0Most of the Universe is NOTStandard Model matter.Instead it is some form ofDARK MATTER34
Density of All Matter ΩMCan measure the density of ALL matter by looking at gravitational effectsRotation curves of galaxiesMotion of galactic clustersThis provides evidence for DARK MATTER sinceΩM 0.4 0.1Even with Dark Matter we cannot account for Ω0 1Universe must 60% DARK ENERGY35
Dark Energy ΩΛIf the expansion of the Universe is slowed by gravitational attraction,expect that in the remote past galaxies were moving apart more rapidlythan now.Observations of distant supernovae show the opposite. Past galaxies aremoving apart more slowly !Expansion of the Universe is accelerating !ΩΛ 0.85 0.2(0.4 0.1) (0.85 0.2) 1.25 0.22ΩM ΩΛ 1Driven by some quantum field permeating the universe36
Supernova Cosmology Projecthttp://www-supernova.LBL.gov37
Supersymmetry (SUSY)α-11 ( µ5040U(1))Forcerceeak FoSU(2) Wα-12 ( µ )30)(3SU10α-13 ( µ )103105Grand Unified#(GUT) ScaleceorgFonStr200E.M.α-1 ( µ )60No Supersymmetry10710910 1110 1310 1510 17Energy Scale, µ[GeV]Inverse coupling constantInverse coupling constantα-1 ( µ )With only the particle content of the SM, unification of the forces does notappear to take place: forces never have the same strengths60U(1) E.50α-11 ( µ)M.Force40SU(2) Weak Force30α-12 ( µ )?e20SU(3)ForcStrongα-13 ( µ )100Grand Unified#(GUT) Scale103105With Supersymmetry10710910 1110 1310 1510 17Energy Scale, µ[GeV]The Higgs mass runs away to the Planck scale (technical issue for SM)Both of these problems can be addressed by an extension to the SM calledSUPERSYMMETRY (also known as SUSY)38
SupersymmetryEach SM boson (fermion) has a fermionic (bosonic)supersymmetric partner with IDENTICAL MASSand Standard Model COUPLINGSleptonssleptons e ν e µ ν µ e τ ν e ν τ u d c s t b µ ν µ τ ν τ u d c s t b Z0W Z 0γγ h0H0h 0H 0A 0W quarkssquarksA0H Spin 1/2Spin 0gg Spin 1Spin 1/2H gauginoshiggsinosgluinos39
Supersymmetry is a Broken SymmetrySupersymmetry requires a doubling of the particle spectrum. Is this cost excessive ?It has been successful before (anti-matter) BUTM e M e M e M e We do NOT see supersymmetric matter made of snucleons and selectronsSupersymmetry is a BROKEN SYMMETRYFor supersymmetry is to solve the problems mentioned require thatMSUSY 1 TeVThis is often referred to as WEAK-SCALE SUPERSYMMETRY40
SUSY and Dark MatterA conserved quantum number (R-parity) distinguishes SM from SUSYparticles: this has two important phenomenological consequences:SUSY particles must be produced in pairsA SUSY particle must decay into SUSY particle SM particle(s)SUSYSUSY SMThe the lightest SUSY particles is cannot decay ! It is STABLE, but doesnot interact with ordinary matter (it is like a neutrino in that respect but isvery massive).Lightest SUSY particle has properties making it a good Dark Mattercandidate (so called Cold Dark Matter or CDM: non-relativistic)WIMP Weakly Interacting Massive ParticleHope to produce SUSY particles at the Large Hadron Collider (and theHiggs Boson as well) starting in 2007.41
Scattering Experiments Particles off a target (Rutherford scattering)Particles of particles (colliding beam)Will see that colliding beams is kinematically superior – more energyavailable to produce new particles in final state (no need to havemomentum in final state.42
Particle DetectorsTrackingDetector(s)γe MuonDetector(s)CalorimetersEMHadronicn, K L0µ π , pn, K L0Neutrinos pass through the detector unobserved. The same would be truefor any neutral, weakly interacting particle (if such particles exist)43
Detector for Fixed Target Experiment44
A Collider DetectorRadial “layering” of detector technologiesRequire cylindrical symmetry and full solid angle coverage (hermiticity)45
Collider ExperimentsLinear Collider: have to accelerate particles in one shotCircular Colliders: particles can travel in circles, slowly being acceleratedup to the required energy over many circuits, then brought into collision.World’s largest collider is being built at CERN, in GenevaLakeGeneva46
The Large Hadron Collider at CERN47
The ATLAS Cavern48
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Hadron Colliders vs Electron Positron CollidersBending a charged particle in a magnetic field costs energy(synchrotron radiation)4 π e 2 β 2γ 41 E 4 or E 43ρmFor fixed radius machine (i.e. in the LEP tunnel at CERN with ρ 6.28km)synchrotron radiation loss for protons less than that for electrons by the amount me mp4 1310 Cannot build electron synchrotrons of arbitrarilyhigh energy. Need either: hadron colliderlinear electron-positron collider (next ?)50
Circular CollidersIn order to keep the particles in a circular orbit, need to bend them withmagnetic fields.7000 GeV protons beams of LHC require VERY strong magentic fieldsRelationship between beam momentum and field required for fixedbending radius:51
LHC Dipole (Bending) Magnet in LHC Tunnel52
The LHC pp Collider at CERN14 TeV pp collider to be installed in the existing 27km ringFirst collisions scheduled for 2007Two general purpose detectors:ATLASand CMSMain objectives: Discover the new TeV scalephysicsDiscovery or exclusion of the SM HiggsDiscovery or exclusion of Weak-Scale SUSY53
Feynman Diagrams for Quark-Quark ScatteringduududWduIf free quarks do not exist, how do we look at such a process experimentally ?54
Collisions at Hadron CollidersHadron colliders can achieve higher centre-of-mass energies thanelectron-positron machines, but ECM of constituent collision 2 E beampproton remnantEbeampx f(x)Ebeam0.6pp-p “collision”quupd0.7qgq0.5q0.3p0.40.20.103 valence quarks sea quarks gluons00.10.20.30.40.50.60.70.80.9proton remnant1xeffectiveqq ′, qq ′, qg , gg collisions at a range of energies 0 ECM 2 EbeamMessy experimental environment for precision measurements, butgreat for discovery of new physics55
Supersymmetric Particle Production at LHCpqHighest cross-section are for strongly interactingSUSY particles (squarks, gluinos)q g q qp q qEach production/decay sequence ends decay to thelightest supersymmetric particle (LSP)pqg q g(at least 100-200 GeV)q p qgpg gg gpmissing E 2· MLSPExperimentally, detect this as an energyimbalance in the detector, since missing massiveparticles carry away undetectable energy in theform of mass and momentumg g g56
The Fate of the Universe If ρ 0, the density of matter and energy in the Universe, is greater than some critical density, ρ c, the expansion of the Universe will eventually cease and reverse, so that it ultimately contracts (THE BIG CRUNCH) If ρ 0, the density of matter and energy in the Universe, is LESS than then critical density,
Nuclear Chemistry What we will learn: Nature of nuclear reactions Nuclear stability Nuclear radioactivity Nuclear transmutation Nuclear fission Nuclear fusion Uses of isotopes Biological effects of radiation. GCh23-2 Nuclear Reactions Reactions involving changes in nucleus Particle Symbol Mass Charge
Guide for Nuclear Medicine NUCLEAR REGULATORY COMMISSION REGULATION OF NUCLEAR MEDICINE. Jeffry A. Siegel, PhD Society of Nuclear Medicine 1850 Samuel Morse Drive Reston, Virginia 20190 www.snm.org Diagnostic Nuclear Medicine Guide for NUCLEAR REGULATORY COMMISSION REGULATION OF NUCLEAR MEDICINE. Abstract This reference manual is designed to assist nuclear medicine professionals in .
12. Which nuclear equation represents artificial transmutation? 13. Which particle cannot be accelerated in a magnetic field? 1. alpha particle 2. beta particle 3. neutron 4. proton 14. Given the nuclear equation: What is the identity of particle X in this equation? 15. Given the equation: When t
property tests. The best particle model had a particle coefficient of restitution of 0.6; particle static friction of 0.45 for soybean-soybean contact (0.30 for soybean-steel interaction); particle rolling friction of 0.05; normal particle size distribution with standard deviation factor of 0.4; and particle shear modulus of 1.04 MPa. Keywords.
q C to heat exchanger for test and evaluation Solex/VPE/Sandia particle/sCO2 shell - and - plate heat exchanger Heat duty 100 kW T particle,in 775 q C T particle,out 570 q C T sCO2,in 550 q C T sCO2,out 700 q C I 6 0.5 kg/s High - Temperature Particle Receiver Particle receiver testing at the National Solar Thermal Test Facility
Particle Properties Particle size By far the most important physical property of particulate samples is particle size. Particle size measurement is routinely carried out across a wide range of industries and is often a critical parameter in the manufacture of many products. Particle size has a direct influence on material properties such as:
NUCI 511 NUCLEAR ENGINEERING I Atomic and nuclear physics, interaction of radiation with matter, nuclear reactors and nuclear power, neutron diffusion and moderation, nuclear reactor theory, the time dependent reactor, heat removal from nuclear reactors, radiation protection, radiation
safety of next-generation nuclear technologies On nuclear security, developing joint projects to secure potentially dangerous radioactive sources and nuclear materials in Central Asia, to prevent illicit trafficking of nuclear and radioactive materials, to improve nuclear security education and training resources, and to expand nuclear security
