tiistai 15. huhtikuuta 2014

+6 Ennen leptoneita olivat hadronit

Large Hadron Collector, Cern, Sveitsi
kuva wordlessTech

Eivät kosmologit Big Bang teoriassa kovin pitkistä ajanjaksoista puhu edes ihmisen kellolla mitattuna.

Leptonit tulevat sekunnin kuluttua alusta laskien.

Mutta miltei koko ensimmäisen sekunnan ajan maailmankaikkeuden massaa hallitsivat hadronit, joita Cernin maailmankuulu hiukkastörmäys laite tutkii. Varsin pieniä kohteita varsin suurella rahalla.

Hadron epoch
In physical cosmology, the hadron epoch was the period in the evolution of the early universe during which the mass of the Universe was dominated by hadrons.

It started approximately 10−6 seconds after the Big Bang, when the temperature of the universe had fallen sufficiently to allow the quarks from the preceding quark epoch to bind together into hadrons.

Initially the temperature was high enough to allow the formation of hadron/anti-hadron pairs, which kept matter and anti-matter in thermal equilibrium.

However, as the temperature of the universe continued to fall, hadron/anti-hadron pairs were no longer produced. Most of the hadrons and anti-hadrons were then eliminated in annihilation reactions, leaving a small residue of hadrons.

The elimination of anti-hadrons was completed by one second after the Big Bang, when the following lepton epoch began.
Okay, very nice!

Hadronien aika alkaa alusta 0.000001 sekuntia ja jatkuu huikeat 0.999999 sejkuntia koko maailmankaikkeuden historiaa.

Mutta mitä ovat hadronit?
In particle physics, a hadron (Greek: ἁδρός, hadrós, "stout, thick") is a composite particle made of quarks held together by the strong force (in a similar way as molecules are held together by the electromagnetic force).

Hadrons are categorized into two families:

  • baryons (such as protons and neutrons, made of three quarks) and 
  • mesons (such as pions, made of one quark and one antiquark). 

A tetraquark state (an exotic meson), named the Z(4430)– was discovered in 2014 by the LHCb collaboration. Other types of exotic hadrons may exist, such as pentaquarks (exotic baryons), but no current evidence conclusively suggests their existence.

Of the hadrons, protons are stable, and neutrons bound within atomic nuclei are stable, whereas other hadrons are unstable under ordinary conditions; free neutrons decay with a half life of about 880 seconds.

Experimentally, hadron physics is studied by colliding protons or nuclei of heavy elements such as lead, and detecting the debris in the produced particle showers.
lue koko artikkeli wikipediasta

Hadronit eivät siis ole perushiukkasia (elementary particles) vaan komposiitteja, jotka koostuvat kvarkeista tai kvarkista ja anti-kvarkista (huom antikvariaatti ei liity näihin)

Riennämme näin kvarkkien pariin.

Alussa oli kvarkkeja.

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