The Search for WIMPS

By Kristine Kovacs

The Big Bang and Beyond

What are WIMPS?

• WIMPS stands for Weakly Interacting Massive Particles

• WIMPS are particles that are thought to possibly be the mysterious dark matter that is missing from the universe

Characteristics of WIMPS

• Predicted only by theory—have not yet been found

• “exotic” particles—means that they are different than the ordinary particles that make up the world around us

• Can travel straight through solid objects• Extremely difficult to detect because they

are not the only things zipping around—there are also alpha particles, gamma-rays, electrons, and cosmic rays

Characteristics of WIMPS Cont.

• Masses are perhaps 10 to 100 times that of protons

• Relatively heavy• Move much slower than the speed of light• Since they don’t interact with radiation,

they would not affect the observed “smoothness” of the cosmic background radiation

• Could contribute up to 90% of dark matter

Detection of WIMPS

• VERY hard to detect—have not even been yet

• Many experiments formed to try to be the first to detect WIMPS

• Can be detected only through very occasional collisions with the nuclei of a suitable target

• A collision causes the nucleus to recoil slightly, which can be detected and measured in various ways

Technologies• ZEPLIN I, ZEPLIN II, ZEPLIN III-liquid xenon scintillators in which

the small amount of energy from the recoil causes photons of light to be released from scintillator material which can then be measured

• Plans for a larger experiment, ZEPLIN-MAX are in the process of being drawn up

• CDMS (Cryogenic Dark Matter Search) Detector-senses the recoil energy when a particle strikes the nucleus of an atom in the crystals (the mass of silicon and germanium crystals located at the heart of the CDMS sensor)

• UKDMC Project-1100 meters below ground in Europe, where the thick rock acts as a natural filter of cosmic rays, and only lets the WIMPS through into the caverns below, where they can be detected

Pictures of Recent Technologies

A cut-away drawing of the new ZEPLIN II detector

currently being constructed

The ZEPLIN I Detector

Works Cited

• http://www.bbc.co.uk/science/space/deepspace/darkmatter/wimps.shtml

• http://www.pbs.org/wnet/hawking/strange/html/strange_wimps.html

• http://www.pparc.ac.uk/frontiers/latest/feature.asp?article=13F5&style=feature

• http://www.space.com/scienceastronomy/generalscience/dark_matter_000228.html