1 / 42

The Future of Particle Physics

The Future of Particle Physics. Steve King, University of Southampton, Masterclass, 24th March, 2009. You are here. The Milky Way Spiral Galaxy. You are here. The Milky Way Local Group: satellites . You are here. The Milky Way Local Group: including Andromeda galaxy.

totie
Télécharger la présentation

The Future of Particle Physics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Future of Particle Physics Steve King, University of Southampton, Masterclass, 24th March, 2009

  2. You are here The Milky Way Spiral Galaxy

  3. You are here The Milky Way Local Group: satellites

  4. You are here The Milky Way Local Group: including Andromeda galaxy N.B. Large galaxies separated by about 1,000,000 pc = 1 Mpc

  5. You are here The Virgo Supercluster: containing Virgo Cluster and our Local Group Each dot is a bright galaxy. Milky Way is dot in the exact centre.

  6. You are here Our Neighbouring Superclusters: Virgo Supercluster at the centre Note the presence of filaments and voids in an irregular cellular pattern.

  7. You are here On the largest distance scales the Universe appears smooth, with no further structures

  8. To understand the origin of the Universe we need to understand high energy particle physics

  9. L L e.g. bats use high frequency sonar with wavelength less than or about same the size of an insect. So, like bats, to see small things we need light with small wavelength and high frequency – hence high energy photons since Why “High Energy”? There are three reasons: • The resolving power of a microscope is limited by the wavelength of the light.

  10. The basic unit of energy is the “electron Volt” which is the energy that a single electron receives when it passes from the negative terminal to the positive terminal of a 1 Volt battery. 2. Einstein taught us that So high energy is equivalent to large mass. With high energies we are able to produce very heavy particles.

  11. 3. Boltzmann taught us that so high energy means high temperature where is Boltzmann’s constant. In the early Universe, just after the big bang, the universe was very small and very hot.So high energy physics teaches us about the early Universe.

  12. Answer: only 84 times! A single atom A nucleus with orbiting electrons nanometre What have we learned from High Energy Physics? - Matter is made of particles (“particle physics”) To understand this, take an apple and a knife, and cut the apple in half once. Then cut one half in half again. Then continue the process. After some number of cuts you will arrive at a single atom. Question: how many cuts are required?

  13. Matter Antimatter Matter The electrical attraction is caused by photon exchange -

  14. The quarks are stuck together by gluons The nucleus of the atom is positively charged It is made of protons (p) and neutrons (n) The protons and neutrons are made of charged quarks The quarks also carry a new “colour charge”

  15. I think I finally understand atoms

  16. This decay process is very weak (15 minutes is an eternity!) Without such weak interactions the Sun would shut down! Nothing lasts for ever The (free) neutron is radioactive and decays after 15 minutes into proton, electron and “neutrino” (electron-like neutral particle)

  17. Photo of Sun taken underground using neutrinos Neutrinos from the Sun Question: How many neutrinos from the Sun are passing through your fingernail in one second? Answer: 40 billion! – day and night since neutrinos can pass right through the Earth without interacting

  18. . . Neutrino Oscillations (only possible if neutrinos have mass)

  19. Electroweak theory predicted a heavy version of the photon called the which was discovered in 1983 W particles – the left-handed alchemists Just like rifle bullets, quarks and leptons spin as they whizz along The quarks and leptons can only see W particles if they spin to the left! This shatters mirror symmetry!

  20. The four forces of Nature

  21. Quarks and Leptons

  22. Mass t u d c e s b What is the origin of the particle masses?

  23. The Higgs Boson In the“Standard Model”the origin of mass is addressed using a mechanism named after the British physicistPeter Higgs.This predicts a new particle:the Higgs boson. What is the Higgs boson? In 1993, the then UK Science Minister, William Waldegrave, issued a challenge to physicists to answer the questions 'What is the Higgs boson, and why do we want to find it?' on one side of a single sheet of paper. This cartoon is based on David Millar’s winning entry.

  24. With such high energy it is hoped to produce the Higgs boson via . 1 TeV The CERN Large Hadron Collider (LHC) will collide protons on protons at energy of 14 trillion electron Volts (14 TeV)

  25. The CERN Large Hadron Collider c.2007 Atlas particle_event_full_ns.mov

  26. 2008 Run… But 200 nOhm of resistance set in between two magnets… an arc… punctured the He containers… Safety issues… so start up September 2009 with running upgrades…probably 10 TeV but running over Winter…

  27. What will the LHC discover? What about Super- symmetry?

  28. Fermions have half units of spin, and tend to shy away from each other, like people who always stay in single rooms at the fermion motel. Bosons have zero or integer units of spin, and like to be with each other, like people who stay in shared dormitories at the boson inn. Supersymmetry says that for every fermion in Nature there must be a boson and vice-versa. Supersymmetric particles have not been observed (yet) so they must be heavier - SUSY must be broken by some mechanism What is Supersymmetry ? There are two types of particles in nature: fermions and bosons.

  29. SPIN ½ FERMIONS SPIN 0 BOSONS Squarks Quarks Sleptons SUSY Leptons The Generations of Smatter The Generations of Matter

  30. BOSONS SUSY Photino FERMIONS Gluino Gravitino

  31. Higgs Boson Higgs Boson Higgsino Higgsino SUSY SUSY SUSY What about the Higgs Boson?

  32. Desperately seeking SUSY

  33. The SUSY Standard Model acts like a Digital radio that eliminates nearly all the fine-tuning The Standard Model requires fine-tuning to one part in a trillion trillion to work! - it is rather like fine-tuning the knobs on an old fashioned radio What has SUSY ever done for us?

  34. So what else has SUSY ever done for us? SUSY provides an excellent candidate for dark matter: the spin ½ partner to the photon which is the lightest SUSY particle and is cosmologically stable called the photino!

  35. Standard Model SUSY Strong Weak Electromagnetic OK, but what else has SUSY ever done for us?

  36. string1.avi Strings live in 11 dimensions

  37. Why wouldn’t we notice extra dimensions?

  38. Both! – nutcracker approach Top-down or bottom-up? Energy 1 trillion trillion Volts 1 trillion Volts

  39. The Next Standard Model The Future of Particle Physics?: Neutrino Physics SUSY Cosmology Strings

More Related