Archive

Posts Tagged ‘antimatter’

Left-Handed Cosmic Magnetic Field Could Explain Missing Antimatter


An artist’s concept of the Fermi Gamma ray Space Telescope (FGST) in orbit. Credit: NASA

An artist’s concept of the Fermi Gamma ray Space Telescope (FGST) in orbit. Credit: NASA

The discovery of a ‘left-handed’ magnetic field that pervades the universe could help explain a long standing mystery – the absence of cosmic antimatter. A group of scientists, led by Prof Tanmay Vachaspati from Arizona State University in the United States, with collaborators at the University of Washington and Nagoya University, announce their result in Monthly Notices of the Royal Astronomical Society.

Planets, stars, gas and dust are almost entirely made up of ‘normal’ matter of the kind we are familiar with on Earth. But theory predicts that there should be a similar amount of antimatter, like normal matter, but with the opposite charge. For example, an antielectron or positron has the same mass as its conventional counterpart, but a positive rather than negative charge.

In 2001 Prof Vachaspati published theoretical models to try to solve this puzzle, which predict that the entire universe is filled with helical (screw-like) magnetic fields. He and his team were inspired to search for evidence of these fields in data from the NASA Fermi Gamma ray Space Telescope (FGST).

Link To Full Story

Using The Sun To Illuminate A Basic Mystery Of Matter


While antiparticles can be created and then detected with costly and complex particle-accelerator experiments, such particles are otherwise very difficult to study. However, Fleishman and the two co-researchers have reported the first remote detection of relativistic antiparticles — positrons — produced in nuclear interactions of accelerated ions in solar flares through the analysis of readily available microwave and magnetic-field data obtained from solar-dedicated facilities and spacecraft. That such particles are created in solar flares is not a surprise, but this is the first time their immediate effects have been detected.

The results of this research have far-reaching implications for gaining valuable knowledge through remote detection of relativistic antiparticles at the Sun and, potentially, other astrophysical objects by means of radio-telescope observations. The ability to detect these antiparticles in an astrophysical source promises to enhance our understanding of the basic structure of matter and high-energy processes such as solar flares, which regularly have a widespread and disruptive terrestrial impact, but also offer a natural laboratory to address the most fundamental mysteries of the universe we live in.

Full Story: http://www.njit.edu/news/2013/2013-228.php

Is Antimatter Anti-Gravity?


Antimatter is strange stuff. It has the opposite electrical charge to matter and, when it meets its matter counterpart, the two annihilate in a flash of light. Four University of California, Berkeley, physicists are now asking whether matter and antimatter are affected differently by gravity as well. Could antimatter fall upward – that is, exhibit anti-gravity – or fall downward at a different rate?

Almost everyone, including the physicists, thinks that antimatter will likely fall at the same rate as normal matter, but no one has ever dropped antimatter to see if this is true, said Joel Fajans, UC Berkeley professor of physics.

And while there are many indirect indications that matter and antimatter weigh the same, they all rely on assumptions that might not be correct. A few theorists have argued that some cosmological conundrums, such as why there is more matter than antimatter in the universe, could be explained if antimatter did fall upward.

In a new paper published online on April 30 in Nature Communications, the UC Berkeley physicists and their colleagues with the ALPHA experiment at CERN, the European Organization for Nuclear Research in Geneva, Switzerland, report the first direct measurement of gravity’s effect on antimatter, specifically antihydrogen in free fall. Though far from definitive – the uncertainty is about 100 times the expected measurement – the UC Berkeley experiment points the way toward a definitive answer to the fundamental question of whether matter falls up or down.

Full Story: http://newscenter.berkeley.edu/2013/04/30/is-antimatter-anti-gravity/

AMS Experiment Measures Antimatter Excess In Space


The international team running the Alpha Magnetic Spectrometer (AMS1) today announced the first results in its search for dark matter. The results, presented by AMS spokesperson Professor Samuel Ting in a seminar at CERN2, are to be published in the journal Physical Review Letters. They report the observation of an excess of positrons in the cosmic ray flux.

The AMS results are based on some 25 billion recorded events, including 400,000 positrons with energies between 0.5 GeV and 350 GeV, recorded over a year and a half. This represents the largest collection of antimatter particles recorded in space. The positron fraction increases from 10 GeV to 250 GeV, with the data showing the slope of the increase reducing by an order of magnitude over the range 20-250 GeV. The data also show no significant variation over time, or any preferred incoming direction. These results are consistent with the positrons originating from the annihilation of dark matter particles in space, but not yet sufficiently conclusive to rule out other explanations.

“As the most precise measurement of the cosmic ray positron flux to date, these results show clearly the power and capabilities of the AMS detector,” said AMS spokesperson, Samuel Ting. “Over the coming months, AMS will be able to tell us conclusively whether these positrons are a signal for dark matter, or whether they have some other origin.”

Full Story: http://press.web.cern.ch/press-releases/2013/04/ams-experiment-measures-antimatter-excess-space

Experiment Makes Measurement of Antihydrogen


In a paper published online today by the journal Nature, the ALPHA collaboration at CERN reports an important milestone on the way to measuring the properties of antimatter atoms. This follows news reported in June last year that the collaboration had routinely trapped antihydrogen atoms for long periods of time. ALPHA’s latest advance is the next important milestone on the way to being able to make precision comparisons between atoms of ordinary matter and atoms of antimatter, thereby helping to unravel one of the deepest mysteries in particle physics and perhaps understanding why a Universe of matter exists at all.

“We’ve demonstrated that we can probe the internal structure of the antihydrogen atom,” said ALPHA collaboration spokesman, Jeffrey Hangst, “and we’re very excited about that. We now know that it’s possible to design experiments to make detailed measurements of antiatoms.”

Full Story: http://press.web.cern.ch/press/PressReleases/Releases2012/PR06.12E.html

Time Reversal: A Simple Particle Could Reveal New Physics

October 15, 2011 Leave a comment

The physics world was rocked recently by the news that a class of subatomic particles known as neutrinos may have broken the speed of light.

Adding to the rash of new ideas, University of Arizona theoretical physicist Bira van Kolck recently proposed that experiments with another small particle called a deuteron could lead to an explanation for one of the most daunting puzzles physicists face: the imbalance of matter and antimatter in the universe.

Full Story: http://uanews.org/node/42347