Physicists make 'strange' matter

Strange matter may exist in neutron stars

By BBC News Online's Helen Briggs

International scientists have made a batch of "strange" particles, in experiments that could further our understanding of the Universe.

This is the first experiment to produce large numbers of these doubly strange nuclei

Adam Usek, Brookhaven

Physicists created atomic nuclei containing two strange quarks at the Brookhaven National Laboratory in the United States.

Since the 1960s, only a handful of such particles have been detected and then only in small quantities.

"This is the first experiment to produce large numbers of these doubly strange nuclei," said Brookhaven physicist Adam Rusek. "That's enough events to begin a study using statistical techniques."

Atom smasher

The experiment took place within a particle accelerator, where atoms were smashed into their constituent particles, the building blocks of matter.

The collisions produced a "significant number" of nuclei containing two strange quarks.

What is the world made of?

Physicists have identified 12 building blocks that are the fundamental constituents of matter

Our everyday world is made of just three of these building blocks: the up quark, the down quark and the electron

Strange matter is composed of up, down, and strange quarks

Out of 100 million collisions, the team found 30-40 examples of the doubly-strange objects.

The 50 physicists - from the US, Canada, Japan, Korea, Russia and Germany - hope to make further studies of the particles. They aim to explore the forces between nuclear particles, particularly within "strange matter".

The research may also contribute to a better understanding of collapsed stars called neutron stars, which could contain large numbers of strange quarks.

Dr Christine Sutton of Oxford University, a spokesperson for the UK Particle Physics and Astronomy Research Council, said: "We know that the physical Universe has more to it than makes the ordinary matter of the world around us.

"This gives us a window into how this more peculiar matter might operate within more exotic locations of the Universe such as in neutron stars," she told BBC News Online.

Strange world

Quarks are elementary particles - pieces of matter that cannot be divided into anything smaller.

The protons and neutrons of normal matter in the everyday world are made of two types of quark - called up and down.

Strange matter, however, is composed of up, down, and strange quarks.

Some theorists have suggested that strange matter may have been formed in the early Universe, and that remnants of this matter may still exist.