Big Bang Black Holes No Math ASTRPHYS 109
Big Bang, Black Holes, No Math ASTR/PHYS 109 Dr. David Toback Lecture 27 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 1
Schedule – L 27 Date Lecture number (class number) Due Before class/11: 55 PM What we do in Class Assigned after class Mon Nov 18 th 24 (25 th period) EOC 14 (A-D), Paper 2 Revisions (if desired) Paper 3 Reviews Chapter 16 EOC 14 (E-G), Unit 6 Reading Wed Nov 20 th 25 (26 th period) EOC 14 (E-G), Unit 6 Reading Chapter 17 EOC 15 & 16, Paper 4, Unit 6 PLRQ Quiz Mon Nov 25 th 26 (27 th period) EOC 15 & 16, Paper 3 Back. Evaluations Chapter 18 EOC 17 & 18 Wed Nov 27 th Reading day, no class Mon Dec 2 nd Redefined day, no class Paper 4 Text Wed Dec 4 th 27 (28 th period, last day of class) Paper 4 Reviews, EOC 17 & 18, Paper 3 Revisions (if desired) Chapters 19 and 20 Chapter EOC 19, AMS II and EOC 20 Mon Dec 9 th No Final Paper 4 Back-Evaluations, EOC 19, AMS II and EOC 20 Notes: • Mis-graded on any Assignment? Let us know • Shorter time period for Paper 4 • There will be a make-up paper on Dark Energy for those of you who missed either the text or a Review/Back-evaluations. Can only replace one of those for one assignment. See the course home page for a link to instructions • Bang, Also investigating a new Times version of if you. Universe want to do the full Big Black Early & Peerceptiv Fate of The 2 assignment Holes, No Math Topic 2: Particle Physics
Was Due for Today – L 40 • General: – Mis-graded on any Assignment? Let us know • Reading: – (Unit 6) • Pre-Lecture Reading Questions Quiz: – (Unit 6) • End-of-Chapter Quizzes: – Chapter 18 • Papers – Paper 3 Revision (if desired): Let us know if you believe you were misgraded – Paper 4: Current plan • Draft for feedback (if desired): Was due Yesterday for guaranteed feedback • Text: Due Monday April 29 th • Reviews: Due Wed May 1 st • Back-Evaluations: Due Monday May 6 th Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 3
Was Due for Today – L 41 • • • General: – Mis-graded on any Assignment? Let us know End-of-Chapter Quizzes: – (Chapter 18) – Will need to do AMS 2 before you can get to Chapter 20 Papers – Paper 3 Revision (if desired): Let us know if you believe you were misgraded – Paper 4: • Draft for feedback (if desired): All feedback posted. • Text: Due tonight, Monday April 29 th • Reviews: Due Wed May 1 st • Back-Evaluations: Due Monday May 6 th Honors Paper: – All Stages must be approved explicitly – Final paper due on the last day of class at 11: 55 PM on e. Campus. Let us know if you need an extension Other Notes: – Make sure you have turned in all papers (including Revisions) into turnitin. You will lose points if you don’t. – Won’t start calculating grades until after May 7 th – Please do the Course Evaluations Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 4
Course Evaluations Course evaluations will be done online: • I believe you should have gotten an email about this already The Spring 2018 evaluation period: • Already Begun (http: //evaluation. tamu. edu/) • Ends Thurs May 10 th, 5 PM Please do them… won’t take long Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 5
Unit 6 Going back in time and going forward in time Before the first millionth of a second and the Fate of the Universe Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 6
Outline of Unit 6 1. Possible Fates of the Universe, Dark Matter and Dark Energy 2. Particle Physics, Dark Today Matter and the Very Early Universe 3. Inflation Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 7
Overview of Today’s Lecture 1. Fundamental particles and interactions 2. What does Particle Physics have to tell us about the Universe before the first millionth of a second? 3. Could the Dark Matter be due to a new type of Particle? Supersymmetry? Big Bang, Black Early Times & Fate of The Universe 8 Holes, No Math Topic 2: Particle Physics
How Physicists Think About This • What are the Fundamental Particles of Nature? • What are the Forces of Nature that keep composite particles together and/or forces them to decay? Can we use this knowledge to help understand the Universe? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 9
Start by listing the particles and interactions we’ve already discussed, then list the others we haven’t discussed Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 10
The Known Fundamental Particles • 6 Types of Quarks – Up, Down, Strange, Charm, Bottom and Top • 6 Types of “electrons” – Electron, Muon, Tau, and a Neutrino for each • 4 Types of Force Carriers – W, Z, gluon and photon Also – Graviton is the 5 th? the recently discovered Higgs Boson which is an oddball that helps “give” Big Bang, Black Early Times & Fate of The 11 the. Universe other mass Holes, No Math Topic 2: Particle Physics
Feynman Diagram of Electromagnetism Hydrogen Atom P P eg e- • A diagram of how the particles “talk” to each other • These two are attracted Time Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics - +
Quarks and the Strong Force • Protons and Neutrons made of quarks • The strong force holds the quarks together inside the nucleon • The force mediator is the “gluon” – Quarks “talk” to each other via gluons Big Bang, Black Early Times & Holes, No Math Fate of The Universe Topic 2: Particle Physics 13
Gravity • The mass of an object attracts it to all other objects • Call this a Gravitational interaction – Haven’t observed the “particle” of gravity interactions yet – Is there one? – Give it a name anyway: “Graviton” Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 14
Interaction: The Weak Force • Responsible for radioactivity, the decay of atomic nuclei • The Particles that “mediate” this interaction are known as the W and Z particles • These particles were predicted in the late 1960’s and discovered in the 80’s – Einstein didn’t know about them Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 15
The Weak Force A Down Quark can “change” into an up quark by “emitting” a W W u d A W can decay into an electron and a neutrino n e W Lives 10 -24 Seconds Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 16
Neutron Decay Neutron Proton + W Proton + Electron + Neutrino W Down Quark Electron Neutrino Up Quark Down Quark Up Quark Neutron Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics Proton 17
Creating Neutron Stars Proton + Electron Neutron + Neutrino Electron W Up Quark Neutrino (leaves the star) Down Quark Up Quark Proton Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics Neutron 18
Other “Weak Force” Interactions Electron+Positron Z muon + antimuon Electron+Positron Z quark + antiquark e+ quark m+ Z e- Antiquark m- Can create lots of different types of particles this way in Big Bang, Black Early Times & Fate of The Universe collisions Holes, No Math Topic 2: Particle Physics 19
Composite Particles Protons and Neutrons Other Examples: Quark and Anti-Quark Pair A Pion and a Kaon Big Bang, Black Early Times & Fate of The Universe Composite particles of 2: quarks called Holes, No Math Topic Particle are Physics “Hadrons” 20
Particle Decay Most of these other composite particles decay after a very short time (~10 -24 seconds) Pion Photon + Photon Up Quark Anti-Up Quark Pion Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics Photon 21
Lots of Others in the Particle Physics “Zoo” Lots more than are listed here… Most are VERY short lived Some are very heavy Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 22
Particle Physics and the Early Universe • If a particle CAN exist and CAN be produced in high energy collisions it WILL (eventually) be produced • Early Universe High Energy collisions Lots of different kinds of particles Bigin Bang, Black Early Times & Universe Fate of The Universe 23 the early Holes, No Math Topic 2: Particle Physics
Each Particle Can be Part of the Story Particle Anti-Particle Photon To understand what really happened in the early Universe requires knowing what all the particles are that can be created Big Bang, Black and Early Times Fate ofinteract The Universe how &they 24 Holes, No Math Topic 2: Particle Physics
Other Fundamental Particles? • Are there other fundamental particles out there we haven’t discovered yet? • How would we know? • Any reason to believe there might be? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 25
Some fun evidence that Dark Matter is Made of Particles Colliding Clusters of Galaxies Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 26
Look at Colliding Clusters of Galaxies Atoms in the Galaxies interact and slow down as they pass through each other Atoms Dark Matter doesn’t interact much so it isn’t slowed down much Dark Matter Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 27
Colliding Galaxy Clusters The atom part and the Dark Matter part of Galaxies interact differently as they pass through each other Atoms and Dark Matter Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 28
Colliding Galaxy Clusters Galaxy Atoms and Dark Matter Galaxy Light from a Galaxy Atoms and Dark Matter Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 29
Evidence for This in Nature? Colliding Clusters of Galaxies Blue is the part from lensing only “Fast Dark Matter” Red part from observing the light “Slow Atoms” Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 30
http: //bigbang. physics. tamu. edu/Figures/Stolen. Animations/bullett_anim_lg. mpg Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 31
What IS Dark Matter? We don’t know… Still working on it… Next we’ll tell you about an exciting possibility we’ve been working on Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 32
Dark Matter = Fundamental Particles? Dark Matter Particles created in the early Universe? Still here today? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 33
Matter and Mediators • All the (fundamental) matter particles act in similar ways – Electrons, quarks, muons etc. • All the mediators act in ways that are different from matter particles, but in ways that are similar to each other – Photons and gluons etc. Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 34
Why are the Matter Particles and Mediators Different? We don’t know… But we have some interesting ideas… Supersymmetry Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 35
Maybe they are more similar than we think? String Theory (and other particle physics theories) predict that they may be related in ways we just haven’t “discovered” yet Since each particle has an anti-particle partner, maybe each matter particle has a mediator partner, and every mediator particle Big Bang, Black Early Times & Fate of The Universe has a matter partner Holes, No Math Topic 2: Particle Physics
Call this “Symmetry” in nature Supersymmetry • Essentially, Supersymmetry predicts that each particle has a “super” partner • Electron Supersymmetric Electron – S-electron or Selectron – Put a ~ on top of it – Quark Squark etc. – W Wino etc. Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 37
The Supersymmetric “Zoo” Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 38
More on Supersymmetry A property of Supersymmetry particles is that we think the number of “superpartners” in an interaction is “conserved” – Almost like electric charge • Always even or odd number of SUSY particles on both sides – Each diagram must conserve charge and “Superparticle number” Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 39
Conservation of Charge and “Superpartner” Number Electric Charge Conserved Superpartner number conserved e- eeg Big Early Times & Fate of The Universe 40 Bang, Black Holes, No Math Topic 2: Particle Physics
So What? • If Superpartner number is conserved the lightest supersymmetric particle can’t decay would last forever – Same reason electrons and protons don’t decay… Nothing they can decay into • If it’s neutral then this could be Matter! Big. Dark Bang, Black Early Times & Fate of The Universe 41 Holes, No Math Topic 2: Particle Physics
Dark Matter = Supersymmetric Particles? Supersymmetric Particles created in the early Universe? Still here today? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 42
Exciting Possibility If this theory is correct: 1. We understand the relationship between matter and mediators (and other important particle physics issues) AND 2. Have solved one of the most important problems in Astronomy and Cosmology Big Bang, Black Early Times No evidence yet… & Fate of The Universe 43 Holes, No Math Topic 2: Particle Physics
A “smoking gun” would be producing them in collision experiments at the LHC at CERN Detector Proton ti e l c er r a P k r a e l c ti r a P r e t t Ma Proton D Ok… Its more t complicated than this t a M since Dark Matter k r don’t easily Big Bang, Black Early Times & Fate Particles a of The Universe 44 D No Math Holes, Topic 2: Particle Physics interact with detectors…
An Aerial View of the LHC Lake Leman CMS Geneva Airport Two huge detectors Collides high energy protons p 27 km in Circumference! One of the largest and the most complex scientific instrument ever conceived & built by humankind p ATLAS Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics
Accelerate protons to REALLY high energies, then bash them together Produce Dark Matter so we can “Discover” it Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics
Final Thoughts on Particle Physics • Why does nature have so many different particles? • Why are some so much heavier than the others? – Protons are 2000 times heavier than electrons – Top quarks are 175 times heavier than protons • How do we know we aren’t missing any? • Could the “fundamental” particles actually be composite? Strings? • Other Forces? Not only are these important fundamental questions, but they are important in cosmology since what particles CAN exist in nature determines what happens in the Very Early Universe Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 47
Lecture on Chapter 19 now complete Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 48
For Next Time – L 40 • • General: – Mis-graded on any Assignment? Let us know Reading: – (Unit 6) Pre-Lecture Reading Questions Quiz: – (Unit 6) End-of-Chapter Quizzes: – If we finished Chapter 19, then Chapter 19 (if not, then just Chapter 18) – Will need to do AMS 2 before you can get to Chapter 20 Papers – Paper 3 Revision (if desired): Let us know if you believe you were misgraded – Paper 4: Current plan • Draft for feedback (if desired): Was due Yesterday for guaranteed feedback • Text: Due Monday April 29 th • Reviews: Due Wed May 1 st • Back-Evaluations: Due Monday May 6 th Honors Paper: – All Stages must be approved explicitly – Final paper due on the last day of class at 11: 55 PM on e. Campus. Let us know if you need an extension Other Notes: – Make sure you have turned in all papers (including Revisions) into turnitin. You will lose points if you don’t. – Won’t start calculating grades until after May 7 th – Please do the Course Evaluations Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 49
For Next Time – L 40 • • General: – Mis-graded on any Assignment? Let us know Reading: – (Unit 6) Pre-Lecture Reading Questions Quiz: – (Unit 6) End-of-Chapter Quizzes: – (Chapter 18) Papers – Paper 3 Revision (if desired): Let us know if you believe you were misgraded – Paper 4: Current plan • Draft for feedback (if desired): Was due Yesterday for guaranteed feedback • Text: Due Monday April 29 th • Reviews: Due Wed May 1 st • Back-Evaluations: Due Monday May 6 th Honors Paper: – All Stages must be approved explicitly – Final paper due on the last day of class at 11: 55 PM on e. Campus. Let us know if you need an extension Other Notes: – Make sure you have turned in all papers (including Revisions) into turnitin. You will lose points if you don’t. – Won’t start calculating grades until after May 7 th – Please do the Course Evaluations Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 50
Rest of the Semester-L 40 Week 15: Next Week • Mon, April 29 th (Lecture 41) – Due: Paper 4 Text – In class: Finish Chapter 19, Start 20 – Assigned: EOC 19 • Tues, April 30 (Lecture 42, Redefined Day, Last day of class) – Due: EOC 19 – In class: Finish Chapter 20 – Assigned: AMS II and EOC 20 • Wed, May 1 st (No class!!) – Due: Paper 4 Reviews, AMS II and EOC 20 • Mon, May 6 th (No class) – Due: Paper 4 Back-evaluations – Paper 4 Revisions will be by request only • Tue, May 7 th (No Final!!) Due: Black Nothing Early Times & Fate of The Universe Big –Bang, Holes, No Math Topic 2: Particle Physics 51
End of Semester Notes - 40 • – • End of Chapter quizzes • While the EOC quizzes are due before then, I’m planning to do my final download on Monday May 7 th at 11: 55 PM • This includes AMS 2 – End of semester measure of some of the things you learned – Will need to do it before you can finish all the end of chapter quizzes If they are not complete, you will get an Incomplete for the course • If you need an extension, let me know ahead of time – Will start calculating grades after May 7 th (after Paper 4 backevaluations are due) – Please do the Course Evaluations There is no statue of limitation on misgraded items. If you think you were misgraded on ANYTHING, we will work to make sure you get the grade you deserve Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 52
For Next Time – L 41 • • • General: – Mis-graded on any Assignment? Let us know End-of-Chapter Quizzes: – If we finished Chapter 19, then Chapter 19 (if not, then just Chapter 18) – Will need to do AMS 2 before you can get to Chapter 20 Papers – Paper 3 Revision (if desired): Let us know if you believe you were misgraded – Paper 4: • Draft for feedback (if desired): All feedback posted. • Text: Due tonight, Monday April 29 th • Reviews: Due Wed May 1 st • Back-Evaluations: Due Monday May 6 th Honors Paper: – All Stages must be approved explicitly – Final paper due on the last day of class at 11: 55 PM on e. Campus. Let us know if you need an extension Other Notes: – Make sure you have turned in all papers (including Revisions) into turnitin. You will lose points if you don’t. – Won’t start calculating grades until after May 7 th – Please do the Course Evaluations Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 53
For Next Time – L 41 • • • General: – Mis-graded on any Assignment? Let us know End-of-Chapter Quizzes: – Chapter 19 – Will need to do AMS 2 before you can get to Chapter 20 Papers – Paper 3 Revision (if desired): Let us know if you believe you were misgraded – Paper 4: • Draft for feedback (if desired): All feedback posted. • Text: Due tonight, Monday April 29 th • Reviews: Due Wed May 1 st • Back-Evaluations: Due Monday May 6 th Honors Paper: – All Stages must be approved explicitly – Final paper due on the last day of class at 11: 55 PM on e. Campus. Let us know if you need an extension Other Notes: – Make sure you have turned in all papers (including Revisions) into turnitin. You will lose points if you don’t. – Won’t start calculating grades until after May 7 th – Please do the Course Evaluations Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 54
Rest of the Semester-L 41 Week 15, This week: • Tues, April 30 (Lecture 42, Redefined Day, Last day of class) – Due: EOC 19 – In class: Finish Chapter 20 – Assigned: AMS II and EOC 20 • Wed, May 1 st (No class!!) – Due: Paper 4 Reviews, AMS II and EOC 20 • Mon, May 6 th (No class) – Due: Paper 4 Back-evaluations – Paper 4 Revisions will be by request only • Tue, May 7 th (No Final!!) – Due: Nothing Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 55
End of Semester Notes - 41 • – • End of Chapter quizzes • While the EOC quizzes are due before then, I’m planning to do my final download on Monday May 7 th at 11: 55 PM • This includes AMS 2 – End of semester measure of some of the things you learned – Will need to do it before you can finish all the end of chapter quizzes If they are not complete, you will get an Incomplete for the course • If you need an extension, let me know ahead of time – Will start calculating grades after May 7 th (after Paper 4 backevaluations are due) – Please do the Course Evaluations There is no statue of limitation on misgraded items. If you think you were misgraded on ANYTHING, we will work to make sure you get the grade you deserve Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 56
Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 57
2 paragraph in-class quiz • Paragraph 1: What are the most important properties of a stellar black hole? • Paragraph 2: How do stellar black holes form? Early Times & Big Bang, Black Early Times & Fate of The Universe 58 Fate of the Holes, No Math Topic 2: Particle Physics
1 Paragraph in-class Quiz • What is the evidence for stellar black holes? Early Times & Big Bang, Black Early Times & Fate of The Universe 59 Fate of the Holes, No Math Topic 2: Particle Physics
Clicker Question Can you "fill up" a black hole? a) Yes b) No Early Times & Big Bang, Black Early Times & Fate of The Universe 60 Fate of the Holes, No Math Topic 2: Particle Physics
Clicker Question Can a Black Hole orbit another star? a)Yes b)No Early Times & Big Bang, Black Early Times & Fate of The Universe 61 Fate of the Holes, No Math Topic 2: Particle Physics
Clicker Question Could the Earth orbit a black hole? a)Yes b)No Early Times & Big Bang, Black Early Times & Fate of The Universe 62 Fate of the Holes, No Math Topic 2: Particle Physics
Clicker Question What would happen if two stellar black holes collided? a) They would make a supermassive black hole b)They would just make a black hole that is has about the same mass as the two original black holes combined Black holes can’t collide Big c) Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 63
Clicker Question If there really is dark energy, what is the ultimate fate of our universe? a) Big crunch b) Expand forever, but slowing down c) Expand forever, but speeding up Black Early Times & Fate of The Universe Big Bang, 64 Holes, No Math Topic 2: Particle Physics
Clicker Question What does dark energy do to the photons in the universe? a) Makes them more energetic by adding energy to the universe b) Stretches them by stretching space time making them more energetic c) Stretches them by stretching space time making them less energetic Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 65
Clicker Question Dark energy is forcing the universe to accelerate. What is accelerating? A) The galaxies moving through space B) The expansion of space-time C) Only the dark matter Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 66
Clicker Question What is happening to the density of the universe over time? a) Increases b) Decreases c) Stays the same Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 67
Clicker Question What does dark energy do to the temperature in the universe? a) Raises it by adding energy to the universe b) Lowers it by stretching spacetime c) Dark Energy doesn’t affect Temperature Big Bang, Black Early Times & Fate of The Universe 68 Holes, No Math Topic 2: Particle Physics
Clicker Question What will happen to galaxies 100 billion years in the future? a) They'll stay the way they are now because dark matter will keep them together b) They'll slowly get ripped apart because dark energy will expand the universe so quickly it will overcome the attraction of gravity Big Bang, Black Early Times & Fate of The Universe 69 Holes, No Math Topic 2: Particle Physics
Clicker Question If space-time is expanding, why aren't atoms expanding? a) They are b) Because the electric charge attraction and quantum mechanics keep the atoms the same size in space c) Both are true, but A is a more important effect than B d) Both are true, but B is more true that A. Black Early Times & Fate of The Universe Big Bang, 70 Holes, No Math Topic 2: Particle Physics
• Interested in learning more next semester? • Take Astronomy 111 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 71
The Story Last Time: • Lots of Evidence for Dark Matter – Don’t know what it is This Time: The Early Universe and Particle Physics – Fundamental and Composite Particles – New idea: Could Supersymmetry Big Bang, Black Early Times & Fate of The Universe 72 explains Dark Matter? Holes, No Math Topic 2: Particle Physics
Other Composite Particles? Protons and Neutrons are composite particles Can we put the fundamental particles together in different ways to create other particles? Yes… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 73
Outline of Today’s Lecture • What are the fundamental particles and their interactions? • Particles, anti-particles and composite particles in the Early Universe • Supersymmetry, if correct, may provide a Dark Matter candidate Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 74
Other Fundamental Particles? 6 Types of Quarks • Up, Down, Strange, Charm, Bottom and Top 6 Types of “electrons” • Electron, Muon, Tau, and a Neutrino for each 4 Types of Force Carriers • W, Z, gluon and photon • Graviton is the 5 th? Fermions Bosons Some are very heavy, Big Bang, Black Early Times & Fate of The Universe Holes, No Math some are very light Topic 2: Particle Physics
Next we move on to the particles and interactions we haven’t talked much about yet… Are there more Fermions or Bosons in Nature? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 76
More fundamental particles? • In the 1930’s Paul Dirac realized that for every particle in nature an anti-particle must exist – Since an electron exists we must be able to create anti-electrons – Same with quarks and anti-quarks • Doubled the particle spectrum Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 77
Writing Assignments Short Assignments 1, 2 & 3 Re-do’s are still possible. Want to revise again? Talk to me e. Learning: Unit 5 past due Need to be working on Unit 6 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 78
Last Paper Due last day of class 1. If you did the Black Hole paper your paper is posted now, on Dark Matter 2. If you did not do the Black Hole paper you must turn in a Research Paper Turn in at e. Learning like usual Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 79
Schedule from Here on Out • Tuesday: Dec 1 st Chapter 20 – The rest of the reading is now due – Be working on e. Learning Unit 6 stuff – Last content for last paper • Thursday: Dec 3 rd Chapter 21 • Tuesday: Dec 8 th Chapter 22 – Paper due at midnight • Thursday Dec 10 th, No classes, Reading period • Tuesday 15 th: Finals week, no final – Paper revisions due Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 80
Problem with answers • If all these particles existed in the early Universe, why aren’t all these particles still around today? • Most types of particles have short lifetimes and would have decayed away • Particles with a long lifetime are still around – Protons – Electrons – Photons etc. Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 81
An Interaction: Electro. Magnetism Positive charge and negative charge attract each other For example, an electron and a positron + - Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 82
Quantum Mechanics and EM Electron “absorbs” a photon g e e e Electron “emits” a photon g e Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 83
Feynman Diagram of Electromagnetism Hydrogen Atom P P eg e- • A diagram of how the particles “talk” to each other • These two are attracted Time Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 84
A Hydrogen Atom The simplest atom: Hydrogen One electron and one proton - | + | ~10 -15 m | ~10 -10 m Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics | 85
Particles: Quarks • Each nucleon is made of 3 quarks • Composed of two different types of quark • Called “up” quarks and “down” quarks • Each quark has fractional charge Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 86
Interaction: Strong Force • The strong force holds the quarks together inside the nucleon • The force mediator is the “gluon” – Quarks “talk” to each other via gluons Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 87
Schedule from Here on Out • Wed April 22 nd: 24 th lecture – The rest of the reading is now due – Stage 1 Research Topic Proposal must be approved – Web. CT Unit 6 stuff • Mon April 27 th: 25 th lecture • Wed April 29 th: 26 th lecture • Mon May 4 th: Class cancelled – Research paper due at midnight after class • Wed May 6 th: No classes, Reading period • Mon May 8 th: Finals week, no final – Paper revisions due Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 88
A Theory • Particle Physicists have been working on to answer these questions for many years • Current best Theory that answers some of them (unproven) Supersymmetry Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 89
Any Experimental evidence for Supersymetric Particles? Not yet… A “smoking gun” would be producing them in collision experiments at Fermilab or the LHC at CERN Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 90
High Energy Collisions Detector M at te r Pa rt ic le Proton k t r a P r e t t a M k Proton r a D Ok… Its more complicated than this since Dark Matter Particles don’t easily interact with detectors… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics ar e l ic 91
Notes: • Now done with Early Times and the Fate of the Universe • Next up: Big objects and Black Holes – Galaxy formation – Star formation – Black Holes • If there is time at the end of the semester – Inflation – Dark Energy Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 92
Paper 1 Results • In general the papers were good • Typical problems include: – Introduction doesn’t outline the paper OR the reasons why we believe – Focused too much on explaining the jargon (Doppler effect) instead of the story (galaxies all moving away from us indicates an explosion) – No interconnection of the topics – Writing was weak. Seek help at the Writing center! • If you aren’t happy with your grade you have 1 week to turn it back in Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 93
Best Papers The best papers all had the same structure 5 paragraphs 1. Intro (Tell WHAT question you are answering and OUTLINE the 3 reasons) 2. Reason 1 (Galaxies moving away) 3. Reason 2 (Expansion of space time) 4. Reason 3 (CBR) 5. Summary and tie it all together Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 94
Feynman Diagrams If a particle and its anti-particle meet they can annihilate and turn into pure energy which turn into something else Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 95
Electrons and Photons Electron Positron Photon Electrons, positrons, and photons can annihilate and pairproduce Occurs frequently in the Early Universe Need to take this into account in our understanding Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 96
A Little History First • The 1930’s -50’s scientists started discovering more “fundamental particles” coming from the Heavens and in high energy collision experiments • “Who ordered that? ” – I. I. Rabi Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics Cosmic Ray Bangs into a detector which “draws” the particle trajectories 97
Collide High Energy Particles to Create New Particles Detector e l ic t r Pa w Anti-Electron e N N ew Pa rt ic le Electron Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 98
Learn some History From Chemistry? • Atoms are not fundamental particles • Each is just a different way of putting together combinations of protons neutrons and electrons • Are the “new” particles “composite? ” Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 99
Particles: Building Blocks of Nature Many of the particles we’ve discussed so far are composite • Atoms = nucleus + electrons • Nuclei = neutrons + protons • Nucleons = a group of quarks Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 100
Quiz What is the primary topic of today’s lecture and WHY are we talking about it? Don’t forget to include your name and today’s date Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 101
For Next Time • Inflation in the Early Universe • More on the story on Dark Matter and the new evidence for Dark Energy Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 102
Any Evidence for This Theory? Lots of indirect evidence, but nothing solid The “smoking gun” would be observing Supersymmetric particles! 1. Collision experiments at Fermilab and the LHC at CERN 2. Dark Matter “interaction” detectors here on earth People at Texas A&M are leaders in both searches! Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 103
Are these Forces all “the same? ” • It turns out that electromagnetism and the weak force are really understood to be a single force called the “electroweak” force… • Haven’t been able to make a successful unification with gravity or the strong force… still working on it… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 104
• The reading for this is SHU 6 and BHOT 11 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 105
BHOT 11 cont… • Force particles can be “grouped” into four categories. • We don’t know if this is really 1 interaction, or 4 separate things (kinda like lots of different atoms, but it turns out that all atoms are really just different combinations of protons and neutrons and electrons) Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 106
• If the force-carrying particle is heavy it will be difficult to produce and exchange them over long distance so the forces will only a short range • On the other hand if the force carrying particles have no mass then their “range” is infinite Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 107
• “What’s the matter in the Universe” Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 108
Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 109
Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 110
Each Particle Can be Part of the Soup Particle Anti-Particle Photon Particle pairs can always produce photon pairs If the photons are energetic enough they can interact and a produce a heavy pair, but those can decay also VERY early times Lots of different Stuff in the Big Bang, Black Early Times & Soup Fate of The Universe 111 Holes, No Math Topic 2: Particle Physics
Why do nucleons stick together? • If what holds the atom together is the opposite charge of the protons and the electrons… Why don’t the same sign charges of the protons “blow the nucleus apart? ” Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 112
Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 113
p uu d n u d du du uu uu d d du u du Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 114
Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 115
Outline • SHU 6? Probably not • BHOT 11 • TCSQ: 1 -? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 116
BHOT 11 • • Theories of Everything Unification of physics Forces of nature Changing the electric charge would change the balance of electromagnetic and gravitational pressures exerted in stars as they burned • If changed only a small amount then life wouldn’t exist Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 117
• Why is the electric charge the way it is? • We don’t know… what a unified theory of everything that tells us WHY it should be the value it is… • What a theory that has BOTH gravity and Quantum Mechanics Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 118
BHOT 11 cont… • Quantum mechanics governs the interactions between the elementary particles (as previously discussed) • They govern the interactions between electrons and the nucleus and give us atoms. • They govern the interactions between the protons and neutrons and give us nuclei • They govern the interactions between quarks to give us protons and neutrons Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 119
BHOT 11 cont… • Picture on page 119 • The force, or interaction, is “carried” by particles • Example: Let’s say we have two electrons (same charge). The way they interact is that the electron emits a force-carrying particle • This causes a recoil of the first electrons (kinda like shooting a gun) • The other electron “catches” it and gets banged (kinda like if you got hit with the bullet) • The net result is that two particles move differently and “as if” there were a force Bigbetween Bang, Blackthem Early Times & Fate of The Universe 120 Holes, No Math Topic 2: Particle Physics
BHOT 11 cont… • This example is the “force” of repulsion of two same charge objects • It turns out each force is transmitted by its own distinctive type of force carrying particle • This force depends on the type of particle doing the “force carrying” • own the forces will be long-range Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 121
BHOT 11 cont… • The force carrying particles exchanged between matter particles are said to be “virtual” because, unlike real particles, they cannot be directly detected by a particle detector • We know they exist because they do have a measurable affect: they give rise to the force between matter particles Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 122
TCSQ 1&2 • Not much to say in chapter 1 • The Standard Model of Particle physics • Does this go in section 2? • Figure 2. 6, page 17. • Protons determine the chemical nature of the atom • Not going to do the history here… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 123
TCSQ 2 cont… • E=mc 2 • The timeline of particle discoveries? Fig 2. 15, page 31 • Anti-particles? • Where does this stuff go? • Matter-anti-matter puzzle. • The particle zoo, page 35, Fig 2. 18. Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 124
TCSQ 2 cont… • Sect 2. 8, quarks • Sect 2. 8, quark pictures and the atom, Fig 2. 19, page 38. • Can just know about the quarks and leptons, need to understand how they interact • This is the stuff about forces. Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 125
The Answer The same strong force keeps the nucleons together Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 126
Forming Protons Quark qqq Proton Nuclear Reaction Quark Proton Quark Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 127
BHOT 11 cont… • First force: Gravity • Universal • Everything feel gravity and how strong the force between particles is depends on their mass or energy • Picture of Earth around sun and light getting bent… Page 77 and page 43. Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 128
BHOT 11 cont… • Gravity continued… We think of gravity being caused by the exchange of virtual gravitons (not yet confirmed). • Gravity is the weakest of the forces by a lot • Two important things to know: – It acts even at long distances – It is (as far as we know) always attractive Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 129
• So what, if objects are really far away we might never notice gravity, but if they are really HEAVY then the attraction can be big • Earth going around the sun • Others tend to cancel out Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 130
BHOT 11 cont… • Force 2: Electromagnetic force • Most people know about this also, it is what causes the interactions between electrically charge particles that we know and love • Electrons and protons • Electrons and quarks • Ignores electrically neutral particles such as neutrons and neutrinos Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 131
BHOT 11 cont… • It is MUCH stronger than gravity • If I have two electrons the electric force between them is so strong that it is 1042 times stronger than gravity • However, we have two types of charge, Positive and negative + and – • This is special because opposite sign attract and same sign repel Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 132
BHOT 11 cont… • So what? Most objects we know and love (the earth, us etc. ) have VERY equal numbers of protons and neutrons (i. e. , objects made of atoms/molecules and they are all electrically neutral or they would attract more charge to make them so) • Bottom line: all the forces from all these charges tend to cancel each other out and there is very little force left over. Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 133
BHOT 11 cont… • However, on the size of atoms and molecules electric charge becomes REALLY important • Its what holds the electrons moving around the nucleus (the protons) • We think of the force between electrically charged things as being caused by the exchange of virtual photons • Cool Feynman diagram here… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 134
BHOT 11 cont… • Force 4: Strong force • This is MUCH stronger than all the other forces • Its what holds the quarks together inside the proton and the neutron • Question: If the electrons are held near an nucleus because they have opposite charge from the nucleus (or the protons in the nucleus), why don’t all the protons (which have the same charge) all scatter apart? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 135
BHOT 11 cont… • The answer is the strong force • It is SO STRONG that it provides more force to keep the protons together than the electric force has to push them apart • Note for the amused: This is why we need neutrons Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 136
• You have to have the extra “strong” particles around to keep it all together. • The strong force is really only between quarks and the force carrying particle is known as the creatively named “gluon” Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 137
Neutron Decay Neutron Proton + Electron + Neutrino Electron Decay Proton Neutrino Neutron Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 138
The Feynman Diagrams Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 139
Other Fundamental Particles? The Standard Model of particle physics has been enormously successful • Why do we need so But: many different particles? • Why are some so much heavier than the others? Big Bang, Black Early Times & Fate of The Universe 140 • How do Physics we know we Holes, No Math Topic 2: Particle
This is a test Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 141
More stuff • This is a test Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 142
Quantum Mechanics – Force Carriers • Why? • We now think of the force between electrically charged things as being caused by the exchange of “virtual” photons • The force, or interaction, is “carried” by particles Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 143
Example with Two Protons • First proton emits a “force-carrying” particle • Causes a recoil of the first proton – You shoot a gung and lurch back • The other proton “catches” it and gets banged – Your friend gets hit with the bullet and falls backward • Net result: The two particles move differently, “as if” there were a force between them Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 144
Diagram 1: Two Protons hanging out 2: Proton on the right “emits” a photon and “recoils” + + 3: Photon bangs into the left proton and bumps it Both now move apart: Same sign charges “repel” each other Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 145
A Proton and Electron 1: A proton and an electron hanging out 2: Proton on the right “emits” a photon and “recoils” - + 3: Photon bangs into the electron Doesn’t transfer Momentum Transfers information on how to move Like signs attract Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 146
Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 147
Photons and Electrons Photons can turn into Electron pairs + - Electron pairs turn into Photons + Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 148
Anti-Matter Stuff • When matter and anti-matter meet they annihilate and disappear in a burst of energy • How could all the matter in the universe exist and be easily detectible if theoretically there should be just as much antimatter around? • Either the matter and antimatter should have annihilated each other, or we ought to be able to detect as much antimatter in the universe, which we clearly do not. • Evidence for anti-electrons (positrons) in 1932 Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 149
SHU 6? ? ? Not here… • This is where the discussion starts about anti-matter. Why is there more matter in the universe than anti-matter? This is still and open question. • At the moment we believe (think? Speculate) that at VERY high energies (very early time) (threshold energies for protons is about 1013 degrees K quarks can interact and produce slightly more quarks than anti-quarks (sphalerons). Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 150
• This takes CP violation to cause it not to go the other way at the same rate • Eventually all the quarks become protons and neutrons (via decay) and eventually the neutrons decay to protons and electrons, thus what we see is proton, neutron, and electron (photon and neutrino) because only those are stable • Its about evolution and decay Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 151
Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 152
Put them together in other ways • This is some text Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 153
This is a test Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 154
Turns out there are other Particles • This is some text Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 155
Very Early Universe is Still Very Complicated • There are lots of other elementary particles we haven’t talked about yet and they have a big impact • One example is a Muon which is (for our purposes) just a heavier version of an electron – More on them later Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 156
Photons and Electrons at 6 Billion Degrees Electron Positron Gamma-ray photon Electron pairs can always produce photon pairs If the photons are energetic enough they can interact and create electron pairs electron and photon Soup Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 157
Photons and Muons At very high energies photons can also turn into Muon pairs + - Muon pairs can turn into Photons + Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 158
Muons Are Part of the Soup Muon Anti-Muon Gamma-ray photon Muon pairs can always produce photon pairs If the photons are energetic enough they can interact and create muon pairs muon and photon Soup Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 159
• Conserved Quantities Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 160
• What about lepton number? • Can’t tell because of the neutrinos? Probably conserved, but no evidence • Charge is also probably conserved • No evidence either way that lepton number isn’t conserved • What about baryon number? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 161
Very Early Universe is Very Complicated What particles exists determine what’s going on in the Very Early Universe Problem: We don’t know if we have discovered all the fundamental particles yet • Good reasons to believe there are new ones out that we just haven’t found yet – Need bigger accelerators and/or Other tools – More on this later also Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 162
TCSQ 2 cont… • Unanswered questions in particle physics • Why do three versions exist of each type of quark and lepton of a given electric charge? • Can the values of the masses of these particles be understood? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 163
• Are there other particle types that are too massive to have been discovered so far? • Are the quarks and leptons structure-less? • Are there other forces yet to be discovered? Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 164
BHOT 11 cont… • Really want to talk about problems of incorporating gravity? • Useful stuff stops at page 122… Big Bang, Black Early Times & Fate of The Universe Holes, No Math Topic 2: Particle Physics 165
- Slides: 165