Tag Archives: proton

Was das Proton umtreibt

Teilchenphysiker der Universität Tübingen weisen erstmals den Gluonen eine wichtige Rolle beim Drehimpuls der Atombausteine zu

Protonen und Neutronen sind Bausteine aller Atomkerne und damit aller Materie. Sie setzen sich ihrerseits aus kleineren Teilchen zusammen, jeweils drei Quarks, die keine eigene innere Struktur aufweisen und durch sogenannte Gluonen aneinander gebunden werden. Das Proton besitzt außerdem einen Drehimpuls („Spin“), von dem Physiker lange annahmen, dass er in erster Linie von den Quarks verursacht wird. 1987 jedoch ergab ein Experiment an der Großforschungseinrichtung CERN, dass der Spin des Protons nur zu einem kleinen Teil durch die Spins der Quarks entsteht ‒ und die Teilchenphysik stürzte in die „Spin-Krise“. Nun haben Wissenschaftler der Universität Tübingen erstmals festgestellt, dass den Gluonen eine wichtige Rolle zukommt und sie möglicherweise den Hauptanteil des Spins tragen.   (more…)

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Testing Einstein’s E=mc2 in Outer Space

UA physicist Andrei Lebed has stirred the physics community with an intriguing idea yet to be tested experimentally: The world’s most iconic equation, Albert Einstein’s E=mc2, may be correct or not depending on where you are in space.

With the first explosions of atomic bombs, the world became witness to one of the most important and consequential principles in physics: Energy and mass, fundamentally speaking, are the same thing and can, in fact, be converted into each other.

This was first demonstrated by Albert Einstein’s Theory of Special Relativity and famously expressed in his iconic equation, E=mc2, where E stands for energy, m for mass and c for the speed of light (squared). (more…)

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First Stars, Galaxies Formed more Rapidly than Expected

Analysis of data from the National Science Foundation’s South Pole Telescope, for the first time, more precisely defines the period of cosmological evolution when the first stars and galaxies formed and gradually illuminated the universe. The data indicate that this period, called the epoch of reionization, was shorter than theorists speculated — and that it ended early.

“We find that the epoch of reionization lasted less than 500 million years and began when the universe was at least 250 million years old,” said Oliver Zahn, a postdoctoral fellow at the Berkeley Center for Cosmological Physics at the University of California, Berkeley, who led the study. “Before this measurement, scientists believed that reionization lasted 750 million years or longer, and had no evidence as to when reionization began.” (more…)

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Cosmic Ray Mystery

Massive detector homes in on cosmic ray production

IceCube, an international collaboration involving University of Delaware scientists, is shedding new light on cosmic ray production.

Although cosmic rays were discovered 100 years ago, their origin remains one of the most enduring mysteries in physics. Now, the IceCube Neutrino Observatory, a massive detector in Antarctica, is homing in on how the highest energy cosmic rays are produced. (more…)

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