Introduction to Experimental Particle Physics : Lecture 5 Graz, September 2012 John Swain, Northeastern University, Boston
Compact Muon Solenoid: CMS
Compact Muon Solenoid: CMS
Rutherford s alpha, beta, gamma rays (1898-1902) http://www.gsseser.com/quarterlies/ helpful2.htm http://library.thinkquest.org/28383/ nowe_teksty/htmla/1_26a.html Now: Helium nuclei, fast electrons (and e+!), photons
Compact Muon Solenoid: CMS
An event in CMS
And another view...
A little on computing Some inventions: programmable computer (1936) Turing -- computer science (1936) Monte Carlo method (1940 s) transistor (1947/1948) integrated circuit (1958) ARPANET (1969) Note that only two are really mathematical
Staggering requirements for LHC http://www.hep.ph.ic.ac.uk/~tapper/talks/cms-trigger.pdf ~1 collision/25 nsec x 1-2Mbytes/event ( so big! ) >> 1 Tb/second pile up: 22 events/bunch crossing Only about 1 event in 1011 is new physics!
ALICE
An ALICE event
Pb-Pb at ALICE Simulated event
Building Up Particles We can find charged particles: electrons, protons, pions, kaons And neutral ones: K0,Lambda (by their decays), gammas (ECAL), neutrons (HCAL and maybe ECAL), even sometimes neutrinos by missing energy How to reconstruct unstable heavier particles?
Lightning review of SR I ll do this on the board... A quick run from Pythagoras to Einstein! Don t blink!
Invariant Mass (Bump Hunting) π 0 ->γγ https://www.e12.physik.tu-muenchen.de/groups/kcluster/researchtopic5.php Add two 4-momenta and get 4-momentum of a particle that decayed Lorentz length is its mass Cuts to select particles and/or clean them up Width is due to natural width and detector resolution Narrow particles can be used to find detector resolution
Can get mass & spin! Mass and spin label the particle (Poincare)! got mass (invariant mass)! spin from angular distributions Might be a new one! Fermi: 1 s an invariant mass, 2 s a cross section, 3 s an angular distribution! Higgs found in the same channel! (Still don t know its width very accurately...detector resolution). Is it really there? Take more data to find out!
The atmosphere as a calorimeter
The Pierre Auger Observatory Schematic picture Use air fluorescence on clear moonless nights and Use ground-based water Cerenkov tanks with GPS timing Hybrid mode allows cross-checks
Pierre Auger Observatory searchsearch
New Detectors JEM-EUSO on the ISS: 50-250x PAO Aperture over 10^19 ev
Neutrinos: High energy 1 cubic km of Antarctic ice + 5160 PMT s Looks for high energy neutrinos, possibly from topological defects or annihilation of SUSY particles
Neutrinos: Low energy Super-kamiokande in Japan: first evidence for neutrino oscillations in 1998 Predecessor KamiokaNDE detected neutrinos from SN1987A and solar neutrinos pointing back to sun in 50 kt of ultrapure 1988 water + 11,146 PMT s
Neutrinos: Low energy 1I 1 kt of heavy water + 9600 PMT s Sudbury Neutrino Observatory in Canada sensitive to NC and thus to all neutrinos clear evidence of neutrino oscillations from the sun
Using a particle as a detector
X-raying The Pyramids Luis Alvarez uses muons to look inside Chephren pyramid (1970) So you didn t find any chambers? Alvarez: No, we found that there are no chambers.
The Future Only just started (~100 years) New acceleration techniques: lasers, wakefields, plasma beatwave,... New things to accelerate: muons? New detectors (SiPM+fibers, tunneling junctions,...) New things to detect: dark matter, cosmic neutrinos,... Neutrino geophysics; cosmic ray archaeology... spin-offs and other applications (medicine, etc.) New concepts entirely new concepts of a particle GR experiments???????? -- Your turn if you want!
Wigner on Physics ``It has been said that the only occupations which bring true joy and satisfaction are those of poets, artists and scientists, and, of these, the scientists are the happiest.''...and I hope you all see Weisskopf s intellectual content of experimental physics
Your turn: the next 100 years! This space intentionally left blank. Thank-you! Vielen Dank!