Materian ja antimaterian välinen epäsymmetria

Hah ! kirjoitti:

Materian ja antimaterian välinen epäsymmetria ei selity nykyisellä hiukkasfysiikan standardimallilla ja kysymys kuuluu, miksei "kaikki" annihiloitunut alkuräjähdyksessä, vaan materia voitti antimaterian baryonigeneesissä.

Fyysikot ympäri maapalloa ovat tätä asiaa tutkineet ja esittäneet erilaisia laajennuksia standardimalliin ja täysin uusiakin spekulaatioita on esitetty lukuisia.

Luonnossa on neljä perusvoimaa (gravitaatio, sähkömagnetismi sekä vahva ja heikko voima) ja tutkijat ovat etsineet viidettä perusvoimaa, joka voisi selittää epäsymmetrian synnyn. Naturessa julkaistiin tänään tuore tutkimus, joka pureutuu tähän yhteen modernin fysiikan keskeisimpään ongelmaan ja tutkijat kertovat löytäneensä ensimmäisiä suoria todisteita eksoottisista päärynänmuotoisista atomeista, jotka voivat antaa vihjeitä viidennestä luonnon peusvoimasta.

"An international team of physicists has found the first direct evidence of pear shaped nuclei in exotic atoms. The findings could advance the search for a new fundamental force in nature that could explain why the Big Bang created more matter than antimatter—-a pivotal imbalance in the history of everything."

"Physicists have been searching for signs of a new force or interaction that might explain the matter-antimatter discrepancy. The evidence of its existence would be revealed by measuring how the axis of nuclei of the radioactive elements radon and radium line up with the spin."

"The researchers confirmed that the cores of these atoms are shaped like pears, rather than the more typical spherical orange or elliptical watermelon profiles. The pear shape makes the effects of the new interaction much stronger and easier to detect.

"The pear shape is special," Chupp said. "It means the neutrons and protons, which compose the nucleus, are in slightly different places along an internal axis."

The pear-shaped nuclei are lopsided because positive protons are pushed away from the center of the nucleus by nuclear forces, which are fundamentally different from spherically symmetric forces like gravity."

"The new interaction, whose effects we are studying does two things," Chupp said. "It produces the matter/antimatter asymmetry in the early universe and it aligns the direction of the spin and the charge axis in these pear-shaped nuclei."

"To determine the shape of the nuclei, the researchers produced beams of exotic—-short- lived—-radium and radon atoms at CERN's Isotope Separator facility ISOLDE. The atom beams were accelerated and smashed into targets of nickel, cadmium and tin, but due to the repulsive force between the positively charged nuclei, nuclear reactions were not possible. Instead, the nuclei were excited to higher energy levels, producing gamma rays that flew out in a specific pattern that revealed the pear shape of the nucleus."

"Our expectation is that the data from our nuclear physics experiments can be combined with the results from atomic trapping experiments measuring EDMs to make the most stringent tests of the Standard Model, the best theory we have for understanding the nature of the building blocks of the universe," Butler said."

http://phys.org/news/2013-05-exotic-atoms-clues-unsolved-physics.html
http://www.nature.com/nature/journal/v497/n7448/full/nature12073.html

kirjoitti:

Anonyymi

Kirjoita kommentti

5000

Lähetä