* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download aspen_pb - Particle Theory
Quantum gravity wikipedia , lookup
Quantum tunnelling wikipedia , lookup
Symmetry in quantum mechanics wikipedia , lookup
Old quantum theory wikipedia , lookup
History of quantum field theory wikipedia , lookup
Nuclear structure wikipedia , lookup
Large Hadron Collider wikipedia , lookup
Canonical quantization wikipedia , lookup
Atomic nucleus wikipedia , lookup
Introduction to quantum mechanics wikipedia , lookup
Eigenstate thermalization hypothesis wikipedia , lookup
Renormalization wikipedia , lookup
Theory of everything wikipedia , lookup
Minimal Supersymmetric Standard Model wikipedia , lookup
Supersymmetry wikipedia , lookup
Double-slit experiment wikipedia , lookup
Relativistic quantum mechanics wikipedia , lookup
Mathematical formulation of the Standard Model wikipedia , lookup
Quantum chromodynamics wikipedia , lookup
ALICE experiment wikipedia , lookup
Theoretical and experimental justification for the Schrödinger equation wikipedia , lookup
Weakly-interacting massive particles wikipedia , lookup
Electron scattering wikipedia , lookup
Strangeness production wikipedia , lookup
Identical particles wikipedia , lookup
Future Circular Collider wikipedia , lookup
Particle accelerator wikipedia , lookup
Grand Unified Theory wikipedia , lookup
ATLAS experiment wikipedia , lookup
Compact Muon Solenoid wikipedia , lookup
1 Invasions in Particle Physics 2 Invasions? “Gentlemen we are being invaded: the accelerators are here” L.Leprince-Ringuet 3 Particle Physics - High Energy Physics High energy particles have extremely small wavelengths and can probe subatomic distances: high energy particle accelerators serve as super-microscopes. The higher the energy the closer particles can come to each other, revealing the smaller details of their structure. The energy of the collisions produces new particles : E=mc 2 The higher the energy the heavier the new particles that can be created. 4 like smashing two cars together and getting a bulldozer out 5 6 21st century particle physics (e.g.) Fermilab’s Tevatron is the highest energy accelerator in the world today. Beams of protons collide with beams of antiprotons 7 antimatter particle accelerators create antimatter by smashing high energy particles onto metals the total amount of antimatter produced in particle accelerators per year ~ 1 microgram even one microgram of antimatter would provide enough energy to drive your car for a month (E=mc2) 8 The SNO detector is more than a mile underground no mass? Yes, photons are massless We thought neutrinos were massless too In 1998 underground experiments discovered that neutrinos have tiny masses 9 32? 7? 6? extra dimensions? Experiments can actually discover them! String theory demands extra dimensions. 10 In 1905 Victor Hess performed a series of high-altitude balloon experiments and found ionizing radiation the origin of which is beyond the Earth’s atmosphere. Cosmic rays were the only source of high energy particles to study until accelerators were developed. 11 Where does this proton come from? 12 one possible source of such high-energy protons: two rings of high-energy particles created from matter from the supernovae remnant falling towards the black hole. 13 detection of high energy particles positron in cloud chamber 14 CLOUD (WILSON) CHAMBER The chamber creates a volume of supersaturated alcohol vapor that condenses on ions left in the wake of charged particles. This is accomplished by establishing a steep vertical temperature gradient with dry ice. Alcohol evaporates from the warm top side and diffuses toward the cold bottom. A layer of supersaturation is created near the chamber bottom. Tracks of alcohol droplets indicate trajectories of charged particles, since each ion becomes a nucleation site for droplet condensation. 15 the pion electron (e) (p) (m) particle tracks left in a photographic emulsion during the decay of a pion. The pion enters moving upwards and comes to rest. It decays to produce a muon, which travels to the right. The muon then decays to an electron, producing the final track leaving at the top right. The pion was discovered by Cecil Powel and Giuseppe Occhialini in 1947 using 16 photographic emulsions at the Pic du Midi, high in the French Pyrrenees. p.s. e, m are leptons e m p Pion picture in a streamer chamber; gas glows brightly along the tracks of the particles. 17 Strange Particles All of these strange particles were unstable. Their origin and purpose was an entire mystery. There were two kinds of them: one kind whose decay products included always a proton were called hyperons and one kind 18 whose decay products only consisted of pions were called kaons. Jack Steinberger “ I remember in 1949, on a bulletin board at the Princeton Institute for Advanced Study, a photomicrograph of a nuclear emulsion event, showing what is now known a a K-meson decaying into three pions. We all saw it. No doubt that something interesting was going on, very different from what was then known, but it was hardly discussed because no one knew what to do with it” 19 20 linear accelerators : The Norwegian Rolf Wideröe realized that, if the phase of the alternating voltage changed by 180 degrees during a particle’s trip between gaps, the particle could gain energy in each gap. The idea of the linear accelerator was born. Wideroe Principle 21 1st circular accelerator (11 inches!) uses both electric and magnetic fields. particles orbit in circles Lawrence and Livingston built the first cyclotron in 1932. It was about 30 cm across, in a magnetic field of about 5000 Gauss and accelerated protons to roughly 1.2 MeV 22 professor’s view 23 mechanical engineer’s view 24 computer scientist’s view 25 theoretical physicist’s view 26 visitor’s view 27 Synchro-cyclotron, Betatron, synchrotron Lawrence McMillan 28 LBL Cosmotron 3 GeV protons Brookhaven National Laboratory(1952) 29 major invasions in accelerator technology Strong Focusing (1952) Colliding Beams (60s) Superconducting magnets (80s) Stochastic Cooling (80s) 30 31 P2K/NASATV movie excerpt After the pion a plethora of new particles called 32 hadrons were discovered in accelerators All hadrons are made of quarks uud p uus S+ uss udd n uds S0/L0 dds S- X0 dss X- strangeness S=0 name nucleon S=-1 sigma S=-2 cascade (ksi) The baryon octet up quark : u down quark : d strange quark : s strangness then is counting how many strange quarks are in these hadrons 33 quarks quarks have not been seen as isolated particles. when you smash hadrons at high energies where you expect a quark, what you observe downstream is a lot more hadrons, NOT fractionally charged quarks. this spray of hadrons is called “jet” Gell-Man 1964: “A search for stable quarks… and/or stable di-quarks … at the highest energy accelerators would help to reassure us of the non-existence of real quarks” 34 35 the Big picture The universe is made out of matter particles and held together by force particles fermions quarks leptons bosons gauge bosons graviton 36 Feynman Graph The electron and quark interact electromagnetically by the exchange of a photon. The lines, wiggles and vertices represent a mathematical term in the 37 calculation of the interaction. Quantum Weirdness The interactions of particles obey the rules of quantum mechanic and of special relativity And particles aren’t really particles, they are quantum fields The fermions (quarks and leptons) are especially weird… 38 Guess 39 the Model What is a model? After 50 years of effort, we have a quantum theory which explains precisely how all of the matter particles interact via all of the forces — except gravity. For gravity, we still use Einstein’s General Relativity, a classical theory that has worked pretty well because gravity effects are so weak. 40 the Standard Model a list of particles with their “quantum numbers”, about 20 numbers that specify the strength of the various particle interactions, a mathematical formula that you could write on a napkin. 41 e e e e u u u d d d u u u m m L d d d Z 0 W W m m L c c c s s s c c c t t t b b b t t t s s s t t t + - g 42 e e e e u u u d d d u u u m m L d d d Z 0 W W m m L c c c s s s c c c t t t b b b t t t s s s t t t + - g 43 e e e e u u u d d d u u u m m L d d d Z 0 W W m m L c c c s s s c c c t t t b b b t t t s s s t t t + - g 44 e e e e u u u d d d u u u m m L d d d Z 0 W W m m L c c c s s s c c c t t t b b b t t t s s s t t t + - g 45 46 what does the Standard Model explain ? your body atoms electrons protons, neutrons quarks 47 what does the Standard Model explain ? 48 neutrino () sky 49 what does the Standard Model explain ? 50 what does the Standard Model not explain ? quantum gravity HST image of an 800 light-year wide spiral shaped disk of dust fueling a 1.2x10^9 solar mass black hole in the center of NGC 4261 51 what does the Standard Model not explain ? quantum gravity dark matter and dark energy 52 what does the Standard Model not explain ? quantum gravity dark matter and dark energy Higgs 53 Arrange it so delicately that it will fall down in 19 minutes. the Bigger Big picture The Standard Model describes everything that we have seen to extreme accuracy. 54 the Bigger Big picture Now we want to extend the model to higher energies and get the whole picture For this we need new experiments and ideas 55 Dirac (1928) matter antimatter special relativity & quantum mechanics 56 supersymmetry (SUSY) fermions bosons every particle has a superpartner particle 57 supersymmetry fermions bosons every particle has a superpartner particle 58 supersymmetry fermions bosons electron quark photino gravitino selectron squark photon graviton none of the sparticles have been discovered yet most of the dark matter in the universe maybe the lightest sparticle 59 60 what do explain ? quantum gravity HST image of an 800 light-year wide spiral shaped disk of dust fueling a 1.2x10^9 solar mass black hole in the center of NGC 4261 61 require 7 extra space dimensions and give us ways to hide them 62 compactification 63 brane-worlds There could be other branes which would look like dark matter to us Standard Model particles are trapped on a brane and can’t move in the extra dimensions how do we see a hidden dimension? ? what particles can move in that dimension ? how big is that dimension ? what is its shape some dimensions are easier to detect than others slice of a 6 dimensional Calabi-Yau space 65 gravitons are the most robust probe of extra dimensions gravity is so weak that we have never even seen a graviton. melectronmelectron F=GN r2 melectron r melectron The gravitational attraction between two electrons is about 1042 times smaller than the electromagnetic repulsion. 66 think about this: gravity gets stronger at extremely high energies (or short distances). it gets stronger at lower energies if there are extra dimensions…. 67 …in which case high energy gravitons may be produced in collider experiments: quark gluon (becomes “jet” of hadrons) antiquark graviton these gravitons probably “escape” into the extra dimension(s) 68 graviton emission simulation: we don’t see the graviton we see a jet from the gluon 69 Collider Detector at Fermilab 70 71 concentric cylindrical layers energy deposited from the particle debris of the collision in the middle 72 “lego” event display 73 Two events are graviton simulation and one is real CDF data: Can you pick the gravitons? 74 two events are real CDF data and one is graviton simulation; Can you pick the graviton? 75 supersymmetry at colliders ~χ 0 1 ~χ 0 1 gluino and squark particles: production and decays 76 e.g. SUSY candidate event at CDF 77 Higgs simulation 78 new accelerators for new physics Linear Collider (?,~2012) Large Hadron Collider (CERN, 2006) 79 underground and in the sky SuperNova Acceleration Probe (SNAP) 80 underground and in the sky KamLAND neutrino detector 81 The coming invasions in particle physics, cosmology and astrophysics will answer (among many other questions) what is the physics that connects the gravitational scale and the scale of the typical mass of the elementary particles what is dark energy and what is dark matter do protons decay what is string theory what are the dimensions and dynamics behind spacetime 82 83