1. Searching for the Higgs Tara Shears University of Liverpool

2. What is particle physics? Study of the infinitessimally small, fundamental parts of matter and their interactions How small is small? ??????

3. Particle physics up down e e charm strange top bottom quarks leptons WEAKELECTROMAGNETICSTRONG GRAVITY

4. What is mass? … energy? … Resistance to gravity? …..property mediated by Higgs Particle

5. Analogy Interaction with Higgs field ( mass) ~ movement of body through medium Light particles do not interact much (move fast) More interaction – slower movement – more mass conferred Heaviest particles …. most interaction

6. What is mass? …property mediated by Higgs Particle nb …… we havent seen it yet ….. ??????

7. Where is the Higgs? LEP (1990-2000) Electrons and positrons collide 40 million x a second Four experiments ??

8. Le Boson de Higgs en ligne de mire Hints of new particle may be massive find for physicists Svelata la particella di Dio Das Teilchen Gottes Czastka Higgsa zlapana? Atom smasher shut as holy grail glimpsed Scientists find Gods particle 11 th hour stuff …

9. Where is the Higgs? September …… December 2000

10. Where is the Higgs? CDF: 706 people 12 countries D0: 650 people 18 countries Fermilab: 2001…2005…. Worlds most powerful accelerator …. still no sign …….

11. Looking for Higgs - LHC Worlds most powerful particle accelerator 2 beams of protons collide 40 million x a second 4 large experiments Due to start in 2007 27 km ? ? ?

12. aside: LHC vs. circle line LHC Circle line Length 27km 22.5km Depth 100m 15m Diameter 3.8m 3.4m

13. Looking for Higgs - experiment eg. …the ATLAS experiment: 5 storey building 7,000 tonnes 42m long 22m wide 22m high 2,000 Physicists 150 Institutes 34 Countries

14. Starting from this event… We look for this signature Selectivity: 1 in 10 13 Like looking for 1 person in a thousand world populations Or for a needle in 20 million haystacks! Finding Higgs 800,000,000 proton- proton interactions per second ~100,000,000 electronic channels 0.0002 Higgs per second

15. HOW do we find the Higgs? Distributed Computing Solution – Grid Concorde (15 Km) Balloon (30 Km) CD stack with 1 year LHC data! (~ 20 Km) Mt. Blanc (4.8 Km) …. a needle in 20 million haystacks! LHC produces enough data to fill 14 million cds / year (1,000,000 times world annual book production!!) Estimated we need 100,000 computers to analyse it all …..

16. grid!

17. summary Search for origin of mass and Higgs major unanswered question Hope for discovery at LHC Immense technological and computing challenge: grid!