LHCb experiment observes new matter-antimatter difference

Apr 24, 2013
A view of the LHCb underground area, looking upwards from the cavern floor Credit: Anna Pantelia/CERN

(Phys.org) —The LHCb collaboration at CERN today submitted a paper to Physical Review Letters on the first observation of matter-antimatter asymmetry in the decays of the particle known as the B0s. It is only the fourth sub-atomic particle known to exhibit such behavior.

are thought to have existed in equal amounts at the , but today the universe appears to be composed essentially of matter. By studying subtle differences in the behavior of particle and , experiments at the LHC are seeking to cast light on this dominance of matter over antimatter.

Now the LHCb experiment has observed a preference for matter over antimatter known as CP-violation in the decay of neutral B0s particles. The results are based on the analysis of data collected by the experiment in 2011. "The discovery of the asymmetric behavior in the B0s particle comes with a significance of more than 5 sigma—a result that was only possible thanks to the large amount of data provided by the LHC and to the LHCb detector's particle identification capabilities," said Pierluigi Campana, spokesperson of the LHCb collaboration. "Experiments elsewhere have not been in a position to accumulate a large enough number of B0s decays."

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Violation of the CP symmetry was first observed at Brookhaven Laboratory in the US in the 1960s in called kaons. About 40 years later, experiments in Japan and the US found similar behavior in another particle, the B0 [superscript 0] meson. More recently, experiments at the so-called B factories and the at have found that the B+ meson also demonstrates CP violation.

All of these CP violation phenomena can be accounted for in the Standard Model, although some interesting discrepancies demand more detailed studies. "We also know that the total effects induced by Standard Model CP violation are too small to account for the matter-dominated universe," said Pierluigi Campana. "However, by studying these CP violation effects we are looking for the missing pieces of the puzzle, which provide stringent tests of the theory and are a sensitive probe for revealing the presence of physics beyond the Standard Model."

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More information: arxiv.org/abs/1304.6173

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mc est
1 / 5 (2) Apr 24, 2013
"How should we make it attractive for them [young people] to spend 5,6,7 years in our field, be satisfied, learn about excitement, but finally be qualified to find other possibilities?" -- H. Schopper

wikimedia.org/wikipedia/en/wiki/Spin_(public_relations)#Techniques

And a warning besides PR spin to non-western members:

"The cost [...] has been evaluated, taking into account realistic labor prices in different countries. The total cost is X (with a western equivalent value of Y) [where Y>X]

source: LHCb calorimeters : Technical Design Report

ISBN: 9290831693 cdsweb.cern.ch/record/494264
baudrunner
1 / 5 (1) Apr 24, 2013
Where very early in this Universe's history the determination of dominance of anti- or pro- matter would have been purely random, as the ratio became weighted toward matter - again purely a random occurrence, like flipping five heads in a row during a coin toss - the preponderance at that time of matter over anti-matter was encouraged by the existing matter acting as a template for its continued dominance. The same phenomenon can occur during chemical synthesis, where seeding an evolving product with a small amount of the pure form can encourage a greater yield. The researchers should be lauded for attempting to quantify and describe this process.
antialias_physorg
5 / 5 (1) Apr 25, 2013
like flipping five heads in a row during a coin toss

During the creation (symmetry breaking) nito matter and antimatter there are rather more 'coin tosses' going on. And the type of matter preponderance of matter we are seeing over antimatter is extremly unlikely to occur naturally.

was encouraged by the existing matter acting as a template for its continued dominance

Unles you have a deeper rational for how such a 'templating effect' should occur I call "Bullshit Bingo" on that statement.
Chemicals aren't a good analogy, since the reaction of matter and antimatter doesn't destroy one and leave the other one intact. (Neither do chemical avalanche reactions for that matter. They just move the system to higher entropy). Ther is a yet no indication that antimatter constitutes a lower entropy state than matter does.

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