* Astronomy

Members Login
Post Info TOPIC: Antimatter


L

Posts: 129912
Date:
RE: Antimatter
Permalink  
 


Anti-matter atoms to address anti-gravity question

The question of whether normal matter's shadowy counterpart anti-matter exerts a kind of "anti-gravity" is set to be answered, according to a new report.
Normal matter attracts all other matter in the Universe, but it remains unclear if anti-matter attracts or repels it.
A team reporting in Physics Review Letters says it has prepared stable pairs of electrons and their anti-matter particles, positrons.

Read more 

Ed ~ anti-matter in most probably will behave like just like normal matter



__________________


L

Posts: 129912
Date:
Permalink  
 

Public Lecture - Our Lopsided Universe: The Matter with Anti-Matter



__________________


L

Posts: 129912
Date:
Permalink  
 

Public Lecture - ANTIMATTER: What is it and where did it go?



__________________


L

Posts: 129912
Date:
Antimatter Imbalance
Permalink  
 


NIST Physicists Chip Away at Mystery of Antimatter Imbalance

Why there is stuff in the universe - more properly, why there is an imbalance between matter and antimatter - is one of the long-standing mysteries of cosmology. A team of researchers working at the National Institute of Standards and Technology (NIST) has just concluded a 10-year-long study of the fate of neutrons in an attempt to resolve the question, the most sensitive such measurement ever made. The universe, they concede, has managed to keep its secret for the time being, but they've succeeded in significantly narrowing the number of possible answers.
Though the word itself evokes science fiction, antimatter is an ordinary - if highly uncommon - material that cosmologists believe once made up almost exactly half of the substance of the universe. When particles and their antiparticles come into contact, they instantly annihilate one another in a flash of light. Billions of years ago, most of the matter and all of the antimatter vanished in this fashion, leaving behind a tiny bit of matter awash in cosmic energy. What we see around us today, from stars to rocks to living things, is made up of that excess matter, which survived because a bit more of it existed.

Read more



__________________


L

Posts: 129912
Date:
RE: Antimatter
Permalink  
 


Measuring the gravitational constant with antimatter

This might not be the most intuitive way to measure g, the gravitational acceleration constant. Nevertheless, this is what a team of about 50 scientists from the AEgIS collaboration (Antihydrogen Experiment - Gravity, Interferometry, Spectroscopy) is trying to achieve. This might soon become even easier, thanks to a recently approved new project to build ELENA, a new decelerator for antiprotons.
Antimatter is not new at CERN. Strictly speaking, we have been producing particles and antiparticles for decades. But producing full atoms is another story. What is much more recent, is that a small group of about thirty physicists from the ALPHA experiment managed to produce anti-hydrogen atoms and keep them for about 1000 seconds.

Read more 



__________________


L

Posts: 129912
Date:
Permalink  
 

CERN experiment weighs antimatter with unprecedented accuracy

In a paper published today in the journal Nature, the Japanese-European ASACUSA experiment at CERN reported a new measurement of the antiproton's mass accurate to about one part in a billion. Precision measurements of the antiproton mass provide an important way to investigate nature's apparent preference for matter over antimatter.
To make these measurements antiprotons are first trapped inside helium atoms, where they can be 'tickled' with a laser beam. The laser frequency is then tuned until it causes the antiprotons to make a quantum jump within the atoms, and from this frequency the antiproton mass can be calculated.  However, an important source of imprecision comes from the fact that the atoms jiggle around, so that those moving towards and away from the beam experience slightly different frequencies.  A similar effect is what causes the siren of an approaching ambulance to apparently change pitch as it passes you in the street. In their previous measurement in 2006, the ASACUSA team used just one laser beam, and the achievable accuracy was dominated by this effect. This time they used two beams moving in opposite directions, with the result that the jiggle for the two beams partly cancelled out, resulting in a four times better accuracy.

Read more



__________________


L

Posts: 129912
Date:
Permalink  
 

LHCb - The Beauty Experiment



A short documentary on the LHCb experiment, on the quest for the mystery of Antimatter.



__________________


L

Posts: 129912
Date:
Permalink  
 

ALPHA Stores Antimatter Atoms Over a Quarter of an Hour - and Still Counting

The ALPHA Collaboration, an international team of scientists working at CERN in Geneva, Switzerland, has reported storing a total of 309 atoms of antihydrogen, some for up to 1,000 seconds (almost 17 minutes), with an indication of much longer storage time as well.
ALPHA announced in November, 2010, that they had succeeded in storing antimatter atoms for the first time ever, having captured 38 atoms of antihydrogen and storing each for a sixth of a second. In the weeks following, ALPHA continued to collect anti-atoms and hold them for longer and longer times.

Read more 



__________________


L

Posts: 129912
Date:
Anti-helium-4
Permalink  
 


Anti-Helium Discovered in the Heart of STAR

Eighteen examples of the heaviest antiparticle ever found, the nucleus of antihelium-4, have been made in the STAR experiment at RHIC, the Relativistic Heavy Ion Collider at the U.S. Department of Energys Brookhaven National Laboratory.
Read more 



__________________


L

Posts: 129912
Date:
RE: Antimatter
Permalink  
 


Title: CPT symmetry and antimatter gravity in general relativity
Authors: M. Villata

The gravitational behaviour of antimatter is still unknown. While we may be confident that antimatter is self-attractive, the interaction between matter and antimatter might be either attractive or repulsive. We investigate this issue on theoretical grounds. Starting from the CPT invariance of physical laws, we transform matter into antimatter in the equations of both electrodynamics and gravitation. In the former case, the result is the well-known change of sign of the electric charge. In the latter, we find that the gravitational interaction between matter and antimatter is a mutual repulsion, i.e. antigravity appears as a prediction of general relativity when CPT is applied. This result supports cosmological models attempting to explain the Universe accelerated expansion in terms of a matter-antimatter repulsive interaction.

Read more  (17kb, PDF)



__________________
«First  <  1 2 3 46  >  Last»  | Page of 6  sorted by
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard