Synopsis: Strangelets in the night

The Moon might be stranger than we think.
Synopsis figure

Normal nuclear matter consists of up and down quarks, which form the protons and neutrons inside atomic nuclei. Bodmer [1] and Witten [2] speculated, however, that the true ground state of hadronic matter might consist of roughly equal amounts of down, up, and strange quarks inside a single hadronic bag. Despite numerous searches for small chunks of such strange quark matter, called strangelets, and despite some “interesting events”, there is as yet no definite evidence for their existence.

If stable strange matter does exist, then what are thought to be neutron stars may in fact be strange stars. A strange star that is a member of a binary star system could collide with its partner and eject strange quark matter into space. Under this scenario, the Moon, with no magnetic field to deflect them, has been subjected for billions of years to a flux of strangelets impacting its surface. These particles would remain fairly undisturbed because of the lack of geological activity on the Moon.

In Physical Review Letters, Ke Han and colleagues at Yale University, in the US, in collaboration with the Massachusetts Institute of Technology, in the US, and the University of Aarhus, in Denmark, report experiments using the Yale accelerator as a mass spectrometer to search for low-mass strangelets in lunar soil brought back by the Apollo 11 mission. The team did not find strangelets within the mass and charge ranges searched, but the data do rule out an unpublished candidate event from the 1998 Alpha Magnetic Spectrometer (AMS) prototype flight. The full AMS experiment is tentatively scheduled for installation on the International Space Station in 2010 and will vastly increase both the sensitivity and the mass range of the search. – Jerome Malenfant

[1] A.R. Bodmer, Phys. Rev. D 4, 1601 (1971).

[2] E. Witten, Phys. Rev. D 30, 272 (1984).


Announcements

More Announcements »

Subject Areas

Particles and FieldsAstrophysicsNuclear Physics

Previous Synopsis

Particles and Fields

Strongly broken symmetry

Read More »

Next Synopsis

Related Articles

Synopsis: Spatial Tests of Dark Matter
Astrophysics

Synopsis: Spatial Tests of Dark Matter

Maps of merging galaxy clusters could help find signatures of dark matter based on its decay into photons. Read More »

Viewpoint: Cavity with Iron Nuclei Slows Down X Rays
Optics

Viewpoint: Cavity with Iron Nuclei Slows Down X Rays

Slow light effects have been measured for x rays using a cavity filled with iron nuclei, where the speed of light was reduced by a factor of 10,000. Read More »

Viewpoint: A More Precise Higgs Boson Mass
Particles and Fields

Viewpoint: A More Precise Higgs Boson Mass

A new value for the Higgs boson mass will allow stronger tests of the standard model and of theories about the Universe’s stability. Read More »

More Articles