1 Antimatter 1Antimatter and the Universe 2Antimatter in the Laboratory 3Antimatter in Daily Life

2 CERN Aerial View

3 1 Antimatter and the Universe Big Bang 13.7 billion years ago How did the energy transform into mass ? (…and atoms, stars, planets)

4 Antimatter Werner Heisenberg (Nobel prize 1932, on quantum theory) ”I think that this discovery of antimatter was perhaps the biggest jump of all the big jumps in physics in the 20th century.”

5 Dirac : Key Discovery Nobel prize 1933 Paul A. M. Dirac Relativity + Quantum Theory ‘Antiparticles’  ‘Antiparticles’ Energy* * gamma rays antiparticle particle

6 Properties of Antimatter Every particle has an antiparticle Example:Electron: Mass = (MeV) Charge = -1 Positron: Mass = (MeV) Charge = +1

7 Is the Universe symmetric? 1933Dirac (from his Nobel lecture) contains a preponderance of negative electrons and positive protons. “If we accept the view of complete symmetry between positive and negative electric charge so far as concerns the fundamental laws of Nature, we must regard it rather as an accident that the Earth (and presumably the whole solar system), contains a preponderance of negative electrons and positive protons.

8 these stars being built up mainly of positrons and negative protons. In fact, there may be half the stars of each kind. It is quite possible that for some of the stars it is the other way about, these stars being built up mainly of positrons and negative protons. In fact, there may be half the stars of each kind. no way of distinguishing them The two kind of stars would both show exactly the same spectra, and there would be no way of distinguishing them by present astronomical methods.”

9 We are still searching the answers. Search for cosmic antimatter Road No. 1:

10 The Search for Antimatter Anti-Nuclei? Gamma-rays ? Solar system? AMS NO …

11 Clue: Our Universe is filled with light ! The Antimatter Mystery Big Bang: 50 % Antimatter Now: 0 % Antimatter How did Antimatter disappear?

12 Without asymmetry - we would not be here!! What kind of asymmetry?? Possible Story Line - The “Annihilation Battle”

13 Sakharov’s Idea A.D.Sakharov Particles decay (a little) faster than antiparticles* Small imbalance (1,000,000,001:1,000,000,000) Occurs during cool-down of Universe Most particle-antiparticle pairs annihilate to radiation Galaxies, stars, planets, us = ‘left-over’ *For experts: this is called ‘CP violation’

14 Could matter and antimatter be different? Fundamental theorem* of physics : “NO” !! *For experts: the ‘CPT theorem’ Experimental physics : “let’s see … “ Compare properties of particles with antiparticles magnetic moment Mass - charge - magnetic moment - lifetime ? For example: Compare electrons and positrons

15 Precision measurements rugth30.phys.rug.nl Electron and Positron are like small magnets. Their magnetic fields are identical to better than Many similar tests - no asymmetry found! But: symmetry violating effects will be very small (if any) %

16 ANTIHYDROGEN - a new precision tool Best known and simplest (anti) atom High precision lasers probe energy levels Comparison: 1 part in ?

17 Anti-Gravity ?? Repeat Galileo’s experiment with (neutral) antihydrogen

18 2 Antimatter in the Laboratory

19 How to study the Big Bang? Collision and detection of accelerated particles Kinetic energy is transformed into new particles

20 History of the CERN pbar source AA 3.57 GeV/c Antiproton Accumulator ring; pbars stored (peak). p/pbar collisions in SPS + low energy experiments in LEAR AAC (AA+AC) Large acceptance Antiproton Collector ring added. Production rate increased 10-fold to 6*10 10 pbars/h ?AD AC converted from fixed energy storage ring to Decelerator. 5*10 7 pbars slowed down to 100 MeV/c (5.3MeV kinetic). Local experimental area.

21 Antiproton Production today 50,000,000 antiprotons (per 90 s) Needs (at least) 6.2 GeV of (proton) energy

22 Cool Antiprotons … Antiprotons produced at speed of light Slow antiprotons down to (almost) rest Accumulate positrons Mixing for antihydrogen formation … Cold Antihydrogen

23 Antiproton Decelerator (AD) Make antiprotons Slow to 10 % of c Eject to experiments

24 Pbar production Ir target, cooled400kA Magnetic Horn for focussing 1.5*10 13 protons yield 5*10 7 pbars

25 Pbar production Magnetic fields used to filter particles w. correct polarity/energy

26 AD cycle

27 Stochastic cooling ALPHA Slot-line type pickup and kicker

28 Electron cooling 30kV 2A electron beam mixed w. pbars thermal exchange, continuously renewed beam

29 View of AD experimental area ALPHA and ATRAP: study antihydrogen ASACUSA: study antiprotonic Helium spectrum ACE: cell irradiation

30 Antiproton trapping

31 3 Antimatter in Daily Life

32 Antiparticles store energy Mass is condensed energy (c 2 = exchange rate!) 1 kg = 9 · J = 2.5 · kWh = 2.85 GW·year (drive VW Polo for 100,000 years without stop)

33 Production ~ 1,000,000,000,000,000 antiprotons/year Antimatter in large quantities? Only milligramme (3 sec on VW Polo) !!

34 Antiproton Tumour Therapy? Antiproton range cm Annihilation Local destruction (nuclear fragments)

35 First results are encouraging Antiproton Cell Experiment (at CERN) Explores antiproton annihilation in cells Comparison with protons, heavy ions Nuclear fragments have short range: Destroy surrounding tissue (<< 1 mm)

36 Summary Antimatter research helps us understand the origin of our (matter) Universe Antihydrogen is an important new tool for precision studies (also gravitation!) Medical applications of antimatter are of great interest