Strange matter
Strange matter ( English strange matter or Strangelet ) consists of strange particles (engl. Strange particles ). These contain the strange quark (of English. Strange , bizarre ') or the Strange- anti quark, characterized have a strangeness of S ≠ 0 and arrive on the earth is not present in stable form. They are called "strange" because they may a. do not disintegrate by the same force that created them.
The first strange particle to be observed in 1947 was the kaon by GD Rochester and CC Butler in a cloud chamber absorbing cosmic rays .
Meaning in the standard model
According to the standard model of elementary particle physics , the strange quark belongs to the second, medium-weight generation of quarks .
Baryons that contain a strange quark are called hyperons and, under normal conditions, decay in a very short time. Also, mesons , which consist of a quark and an anti-quark can, the strange quark contain (for. Example, the kaons). Particles with two strange quarks are called "doubly strange particles".
Astrophysicists assume that in heavier neutron stars from about 1.5 solar masses under sufficiently high pressure of gravity, the existing neutrons break down into their quark components ( quark stars ), with one of the two down quarks converting into a strange quark. With this, neutron stars could be places where strange matter can exist stably. For some time the neutron star RX J1856 in the constellation Southern Crown was suspected as such a candidate, but recent measurements have since refuted this assumption.
Hypothetical properties
According to theoretical considerations, stable Strange Matter could pose a risk. According to this, small amounts of free strange matter are supposed to absorb normal matter and also convert it into stable free strange matter. It is argued that strange matter becomes more stable with increasing mass number and could be completely stable from a mass of approx. 1000 protons . According to calculations by Jens Madsen from Aarhus University , very small amounts of strange matter are too unstable to react with atomic nuclei . Larger quantities with a mass of approx. 1000 protons, on the other hand, can hardly be produced technically. Calculations of this kind also play a certain role in the risk assessment of modern particle accelerators such as that of the Large Hadron Collider .
Since no evidence of the actual existence of processes has been found in nature in which normal matter is converted into stable strange matter by free strange matter, it is generally assumed that artificial processes pose no danger from the artificially generated strange matter .
Trivia
In the novel The Crater by Douglas Preston , Strange Matter plays an essential role and is used as a weapon by an alien force.
The science thriller Strange Matter by Thor Ansell bases its plot on a cosmic event in which strange matter from a star explosion hits the earth and causes all sorts of bizarre quantum mechanical interactions.
See also
literature
- Wolfgang Demtröder: Experimental Physics . 2nd Edition. tape 4 : Nuclear, Particle and Astrophysics . Springer, Berlin 2004, ISBN 3-540-21451-8 .
- Jonathan L. Rosner, Bruce D. Winstein: Kaon Physics . Univ of Chicago Pr, 2001, ISBN 0-226-90228-5 .
Web links
- The Story of Strangelets (English)
Individual evidence
- ^ GD Rochester, CC Butler: Evidence for the Existence of New Unstable Elementary Particles . 1947, doi : 10.1038 / 160855a0 ( nature.com ).
- ↑ Timothy M. Braje, Roger W. Romani: RX J1856-3754. Evidence for a Stiff Equation of State . In: The Astrophysical Journal . tape 580 , no. 2 , 2002, p. 1043-1047 , doi : 10.1086 / 343895 , arxiv : astro-ph / 0208069 .
- ↑ Edward Witten: Cosmic separation of phases . In: Physical Review D (Particles and Fields) . tape 30 , no. 2 , 1984, p. 272-285 , doi : 10.1103 / PhysRevD.30.272 .