The mysterious substance known as dark matter may actually be an illusion created by gravitational interactions between short-lived particles of matter and antimatter, a new study says. (via Dark Matter Is an Illusion, New Antigravity Theory Says
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cwnl:
Muon Wobble Possible Door to Supersymmetric Universe
How fast do fundamental particles wobble? A surprising answer to this seemingly inconsequential question is coming out of Brookhaven National Laboratory in New York, USA and may not only indicate that the Standard Model of Particle Physics is incomplete but also that our universe is filled with a previously undetected type of fundamental particle. Specifically, the muon, a particle with similarities to a heavy electron, has had its relatively large wobble under scrutiny since 1999 in an experiment known as g-2 (gee-minus-two), pictured above. The result galvanizes other experimental groups around the world to confirm it, and pressures theorists to better understand it. The rate of wobble is sensitive to a strange sea of virtual particles that pop into and out of existence everywhere. The unexpected wobble rate may indicate that this sea houses virtual particles that include nearly invisible supersymmetric counterparts to known particles. If so, a nearly invisible universe of real supersymmetric particles might exist all around us.
Credit: R. Bowman, g-2 Collaboration, BNL, DOE
(Source: ikenbot)
ANTIPROTONS appear to ring the Earth, confined by the planet’s magnetic field lines. The antimatter, which may persist for minutes or hours before annihilating with normal matter, could in theory be used to fuel ultra-efficient rockets of the future.
Charged particles called cosmic rays constantly rain in from space, creating a spray of new particles - including antiparticles - when they collide with particles in the atmosphere. Many of these become trapped inside the Van Allen radiation belts, two doughnut-shaped zones around the planet where charged particles spiral around the Earth’s magnetic field lines.
Satellites had already discovered positrons - the antimatter partners of electrons - in the radiation belts. Now a spacecraft has detected antiprotons, which are nearly 2000 times as massive.
Heavier particles take wider paths when they spiral around the planet’s magnetic lines, and weaker magnetic field lines also lead to wider spirals. So relatively heavy antiprotons travelling around the weak field lines in the outer radiation belt were expected to take loops so big they would quickly get pulled into the lower atmosphere, where they would annihilate with normal matter. The inner belt was thought to have fields strong enough to trap antiprotons, and indeed that is where they have been found.
(via Antiproton ring found around Earth - space - 04 August 2011 - New Scientist)
cwnl:
Why the universe is filled with matter rather than antimatter is one of the great mysteries in physics. Now we are a step closer to understanding it, thanks to an experiment which creates more matter than antimatter, just like the early universe did.
Our best understanding of the building blocks of matter and the forces that glue them together is called the standard model of particle physics. But this does a poor job of explaining why matter triumphed over antimatter in the moments after the big bang.
The standard model has it that matter and antimatter were created in equal amounts in the early universe. But if that was the case they should have annihilated in a blaze of radiation, leaving nothing from which to make the stars and galaxies. Clearly that didn’t happen.
A quirk in the laws of physics, known as CP violation, favours matter and leaves the universe lopsided. The standard model allows for a small amount of CP violation but not nearly enough to explain how matter came to dominate. “It fails by a factor of 10 billion,” says Ulrich Nierste, a physicist at the Karlsruhe Institute of Technology in Germany.
Now researchers at DZero, an experiment at the Tevatron particle accelerator at Fermilab in Batavia, Illinois, have found the largest source of CP violation yet discovered. It comes courtesy of particles known as Bs mesons (arxiv.org/abs/1106.6308).
These are unusual particles because they can transform into their own antiparticle and back again, says Guennadi Borissov, a member of the DZero team based at Lancaster University, UK. That makes them perfect for studying CP violation.
Last year, the DZero experiment studied collisions between protons and antiprotons that create Bs mesons, which then decay into muons. Sure enough, the team found more muons than antimuons, signalling that more matter is created than antimatter.
However, particle physics is littered with findings that disappear as more data is collected. Now Borissov and his colleagues have repeated the study using data from 50 per cent more collisions and the new result boosts the original conclusion (Physical Review Letters, DOI: 10.1103/PhysRevLett.105.081801). “The most likely interpretation is an anomalously high CP violation,” says Guy Wilkinson at the University of Oxford.
(Source: ikenbot)
Beauty of Science: Picture of Neutrino Processed At FermiLab
Interaction in the Fermilab 15-foot Bubble Chamber with heavy neonhydrogen liquid mixture taken in April, 1976. Nearly one neutrino interaction per picture is found with the current run targeting 1013 protons at 400 GeV with the wide band - two horn system. Frequently the chamber is flooded with tracks from several neutrino interactions in the same exposure. In addition to increasing the interaction rate, the heavy neon mixture allows many of the particles from neutrino interactions to be recognized by direct inspection of the track appearance: protons, charged pions and kaons produce secondary interactions; neutral pions are evidenced by their gamma rays converting to electron pairs; muons sail right through the liquid without interacting and direct electrons or positrons from the vertex are recognized by successive kinks and associated gamma ray conversions along their tracks. A major interest in the present experiment by a Columbia University-Brookhaven Laboratory collaboration is the study of “di-lepton” events in which two muons or a muon and an electron are produced in high energy neutrino interactions.
Credit: FermiLab
The slightly stripped-down version of this that you’ve probably seen before is my next tattoo. It’s going to hurt like a bitch.
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