1Erik Johansson Athens 2010

Particle collisions and antimatter

In the ATLAS Experiment

Erik JohanssonStockholm University

ATLAS

3.5 + 3.5 TeV

The colossal ATLAS detector at CERN

People

http://atlas.ch

4Erik Johansson Athens 2010

Learning with ATLAS

ATLAS particle collisions

for teachers and students

Learning with ATLAS@CERN

http://www.learningwithatlas-portal.eu/sv

5Erik Johansson Athens 2010

Students and ATLAS

• Take part in an world-wide particle physics experiment• Use the same data, same tools and methods as the

physicists• Explore the invisible particle world• In our surrounding we experience protons, neutrons

and electrons, but there are many more....• At the Big Bang they were all needed to give rise to the

present universe

6Erik Johansson Athens 2010

Particle collisions in ATLAS

December 2009 datataking

A neutral strange particle produced in a proton-proton collision, and decaying in the Inner Detector of ATLAS

Students can determine its mass and lifetime

http://www.learningwithatlas-portal.eu/sv

7Erik Johansson Athens 2010

Some Special Relativity

• Reconstructing invisible particles• Some special relativity

E2 = p2c2 + m2c4

Rest energy: E = mc2

M = square root (E2/c4- p2/c2)where E is the total energy and p is the total momentum (vector sum) of the produced particles

9Erik Johansson Athens 2010

New Physics Brochure

10Erik Johansson Athens 2010

ATLAS on other arenas

ATLAS on other arenas –

The Web, YouTube and Hollywoodfilm

11Erik Johansson Athens 2010

ATLAS Homepage

12Erik Johansson Athens 2010

13Erik Johansson Athens 2010

Five minutes about the LHC. Much filmed inside ATLAS cavern (with a few “enhancements”).

Film is now on DVD with an extra about CERN and ATLAS

Through two trips to the headquarters of Sony Pictures in Los Angeles, we negotiated to have a 15-minute extra on the DVD.

14Erik Johansson Athens 2010

15Erik Johansson Athens 2010

1/2 gram of antimatter

• ½ g of antimatter is a huge amount of antimatter• Will take ATLAS 10 million years to produce it

– Difficult to put it in a container

• 1 g of matter corresponds to around 6 1014 J.– Order of magnitude: World War 2 atomic bomb

16Erik Johansson Athens 2010

ATLAS and Antimatter

• Antimatter and Other Mysteries in the ATLAS Experiment– 24 page brochure

17Erik Johansson Athens 2010

Student projects

• What is antimatter?• How is antimatter produced in ATLAS?• How would you transport antimatter?• How much energy does 1 g of matter (½ g of antimatter

and ½ g of matter) correspond to?• How much is that compared to a nuclear bomb?• How many people’s yearly anergy consumtion does it

correspond to?• How much mass does 7+7 TeV energy correspond to?• Compare it with a stellar black hole.

19Erik Johansson Athens 2010

Microscopic Black Holes

• 14 TeV collisions at the Large Hadron Collider– corresponds to around 3 10-23 kg

• A stellar black hole > 10 solar masses, 2 1031 kg• Particularly light black holes emit Hawking radiation

– Hawking 1974

• A microscopic black hole would evaporate immediately

• It would not gobble up CERN, Canton de Genève, Switzerland....

• For journalists the end of the world is a great story

Simulated Microscopic Black Hole

21Erik Johansson Athens 2010

ATLAS particle collisions excite students

Make a determination of the mass and the short lifetime, 10-10 s of a ‘strange’ particle

Making the invisible visible is an exiting challenge

The new arenas – web, YouTube, Hollywood film create exceptional opportunities

The majority of your students have seen ‘Angels and Demons’

Summary