1 Stefan Spanier, 22 October 2008 Research Participation in Collider Based Particle Physics Stefan Spanier University of Tennessee, Knoxville

2 Stefan Spanier, 22 October 2008 Cathode Ray Tube  electron Experiments 111 years ago … fundamental building block of matter "Could anything at first sight seem more impractical than a body which is so small that its mass is an insignificant fraction of the mass of an atom of hydrogen?" J.J. Thompson: Cathode rays are material constituents of atoms! bend in electric and magnetic field Nobel Prize 1906 G.P. Thompson: electrons have wave character Nobel Prize 1937

3 Stefan Spanier, 22 October 2008 Particle Accelerator as Microscope Length to be resolved R R  1/Particle Energy 1eV = kinetic energy an electron gains in a electric field of 1 Volt 1.0 V > 100 MeV ~ keV > 10 MeV > 100 GeV

4 Stefan Spanier, 22 October 2008 u c t d s b d s b u c t e -     e    e    e +     ___ ___ __ _ Charge + 2/3 - 1/3 0 Charge + 1/3 - 2/ Quarks Leptons mass particles anti-particles Standard Model does not ‘predict’ any of the masses (parameters); How do masses come about? Latest addition 1995 Tevatron at Fermilab The Standard Model Building Blocks

5 Stefan Spanier, 22 October 2008 How particles acquire masses … The Higgs particle mass generation The Higgs Field

6 Stefan Spanier, 22 October 2008 Electric Magnetic Photons m= 0 Weak W +,W -,Z 0 m= 80, 90 GeV Strong Gluons m = 0 Gravity Gravitons ? Maxwell electroweak ~100 GeV Standard Model Planck energy ~ GeV today’s accelerators just about … ~ GeV ? GUT scale coupling constants unify Higgs mechanism Forces Seems unnatural ?

7 Stefan Spanier, 22 October 2008 GUT Force relative coupling Strong  S 1  0.12 Electromagnetic  1/137  1/128 Weak  W Gravity  G Behavior of coupling constants supports idea, but no common intersection?  introduce e.g. Supersymmety ? least understood 1 strength weak strong

8 Stefan Spanier, 22 October 2008 Supersymmetry ??? Simplest super-symmetric model has 105 new parameters … Boson  Fermion symmetry Spin ½ quarks  spin 0 squarks Spin ½ leptons  spin 0 sleptons Spin 1 gauge bosons  spin ½ gauginos Spin 0 Higgs  spin ½ Higgsino  Many particles to search for! What mass scale? Supersymmetry is broken...no scalar with mass of electron Observation: -as missing mass (energy) if non-interacting (lightest neutralino) - from decay into the lower mass standard particles

9 Stefan Spanier, 22 October 2008 What is dark matter? How are particle physics & cosmology connected? What is dark energy? Where did the anti-matter go? (CP Violation) Stars and galaxies are only 0.1% Neutrinos are ~0.1–10% Electrons and protons are ~5% Dark Matter ~25% Dark Energy ~70% The Cosmic Connection

10 Stefan Spanier, 22 October 2008 The LHC Machine and Experiments LHCf totem  High Energy factor 7 increase w.r.t. present accelerators  High Intensity (# events/reaction/time)  factor 100 increase  High Energy factor 7 increase w.r.t. present accelerators  High Intensity (# events/reaction/time)  factor 100 increase Proton-proton collisions at 14 TeV 27 km in circumference, m deep

11 Stefan Spanier, 22 October 2008 LHC superconducting dipole magnet Energy stored/beam: 360 MJ Energy stored in magnets: 700GJ  Particle losses fatal ! Superconducting magnets: 1232 dipole magnets (bending) T=1.9 K (superfluid Helium) B – field > 8 Tesla ~500 quadrupole (focus)magnets LHC in LEP tunnel

12 Stefan Spanier, 22 October 2008 LHC – Beam 1 first + second turn

13 Stefan Spanier, 22 October 2008 A Higgs Event in the Compact Muon Solenoid Luminosity = cm -2 s -1 = 10 7 mb -1 Hz Interaction rate = 8 x 10 8 Hz Interactions/crossing = 25 (~1000 charged particles) pp ++ -- -- ++ Higgs event + ~25 minimum bias events Simulation H Z

14 Stefan Spanier, 22 October 2008 The CMS Detector Muon chambers RPCs, DT (barrel), CSC (end) Superconducting coil 4Tesla, 20000A, -270 o C Iron return yoke EM Calorimeter #80k PbWO 4 crystals Width: 22m Diameter: 15m Weight: 12,500 tons Hadron Calorimeter Brass + scintillator Vacuum chamber Central Tracker 66M Si-Pixel 10M Si-Strip Area: 220 m 2 Very forward calorimeter

15 Stefan Spanier, 22 October 2008 The Pixel Detector Barrel layers at radii = 4.3cm, 7.3cm and 10.2cm Disks at +/-z = cm and cm Pixel cell size = 100x150 µm 2  ~1m 2 of silicon / 66 Million pixels ~15k front-end chips and ~1 m 0.3 m z

16 Stefan Spanier, 22 October 2008 The Pixel Detector Principle ~285  m After 1 st year z B Primary signal electrons; Lorentz force smears charges Resolution: within square: ~25  m Charge sharing: 10 – 15  m MIP  e -

17 Stefan Spanier, 22 October 2008 Pixel Diamond Detector – New Technology Pixel Luminosity Telescope prototype pixel readout at UTK

18 Stefan Spanier, 22 October 2008 Computing 15 Million Gigabytes of data each year (about 20 million CDs!) GRID Node at UTK 10 GBit/s connection; 246 processors + 50TByte storage

19 Stefan Spanier, 22 October 2008 The Commissioning / Operation