Strange Antihyperparticle Created

Mar 30, 2010

(PhysOrg.com) -- Physicists, including nine from UC Davis, working at the U.S. Department of Energy's Brookhaven National Laboratory recently created some strange matter not seen since just after the Big Bang -- an "antihypertriton" composed of antimatter and "strange" quarks. A paper describing the work was published online this month in the journal Science.

If researchers can create and study enough of these particles, they can start to address deep problems in physics, such as why the universe is made of matter at all, said Manuel Calderon de la Barca Sanchez, associate professor of physics at UC Davis and part of the project team.

A triton is the nucleus of the : a proton and two neutrons. A is made up of three , two "down" and one "up." In a hypertriton, one of the neutrons is replaced by a particle called a lambda hyperon, with one "up," one "down" and one "strange" quark. A hypertriton was observed for a fleeting moment in a lab experiment about 50 years ago, Calderon said.

Calderon and his colleagues detected the antihypertriton when they used Brookhaven's Relativistic Heavy Ion Collider to slam into each other at enormous speed. The energy released in these collisions creates new particles in a "," similar to that which existed microseconds after the beginning of the universe.

The antihypertriton, as its name suggests, is a hypertriton in which the up, down and strange quarks are replaced with antimatter equivalents (anti-up, anti-down and anti-strange quarks).

The particle decayed so quickly that the Brookhaven experiment could only record its distinctive decay products. The researchers collected evidence of about 70 antihypertritons from 100 million collisions.

Being able to make these antinuclei opens up a new field of nuclear physics, Calderon said.

According to theory, equal amounts of matter and antimatter should have been created in the Big Bang. However, if that were the case, the two kinds of matter would have canceled each other out, leaving nothing at all. Instead, the Big Bang yielded an observable universe made mostly of matter -- with rare and fleeting particles of antimatter. Physicists call this problem CP violation, and it is one of the biggest unsolved problems in physics.

The Science paper was authored by the STAR Collaboration, which is composed of 54 institutions from 13 countries. Analysis of the hypertriton data was by Jinhui Chen, Kent State University (currently at Shanghai Institute of Applied Physics). The UC Davis members besides Calderon include Daniel Cebra, professor of physics; professor emeritus Jim Draper; postdoctoral researchers Debasish Das and Haidong Liu; research physicist Juan Romero; and graduate students Brooke Haag, Rosi Reed and Evan Sangaline.

Explore further: Neutrino trident production may offer powerful probe of new physics

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seneca
not rated yet Mar 30, 2010
Well, it's first strangelet. Albeit not very pure one...
migmigmig
not rated yet Apr 04, 2010
No, "strangelet" matter does not get bound up into nuclei.

Strangelets are their own type of matter and finding one in a high-energy experiment would be Nobel-worthy work.

Strange quarks in baryons are not stable at all, it's only when you get a bunch of them in a soup with up and down quarks that you can go to the hypothetical lower-energy state of strangelet quark matter (which is why it would accrete, supposedly).

broglia
not rated yet Apr 15, 2010
IMO Strangelets are basically atom nuclei, composed of strange quarks hadrons only. They're expected to be of positive charge, too. In real case we can obtain atom nuclei with mixture of normal and strange quarks which are instable, but the pure strange atom could become considerably stable, because of its generally smaller size and thus surface tension pressure, which should stabilize it. As usually, the purity introduces new interesting (and potentially dangerous) synergies into physics. So you shouldn't extrapolate stability of strangelets from stability of mixed atom nuclei, which are generally less stable, then both strangelets, both normal atoms.
broglia
1 / 5 (1) Apr 15, 2010
..finding one in a high-energy experiment would be Nobel-worthy work...

OK, but why we should all evaporate - just because few trolls are hoping to get Nobel price? Anyway, I don't see nothing spectacular on the strangelet concept at conceptual level.