Deep under the mountain
of Gran Sasso in central Italy, under almost a mile of solid rock,
the CUORE (cryogenic
Underground Observatory for rare events and Italian for "heart")
The experiment is underway to help us understand one of the great unanswered questions in astrophysics: Why is the universe that surrounds us full of it?
important if predictions suggest that it should be split evenly
Matter and antimatter
For each atomic particle
there is a complementary particle of equal mass, but opposite
Charge: this is the case with electrons and positrons, for example
Protons and antiprotons, neutrons and antineutrons. For every couple of
One particle is called ordinary matter and the other is called
Antimatter (the only exception being Majorana fermions, charged particles ̵
as their own antiparticles.
Astrophysics tells us
that the Big Bang should have produced equal amounts of matter
Antimatter, but that is clearly not the case. The reason for that
The imbalance is still a mystery, but may be in the nature of it
Neutrino, an almost massless subatomic particle that – just like that
Photon – can act as its own antiparticle. If neutrinos are indeed
Majorana fermions, they may have fallen asymmetrically in the early years
Universe and the preponderance of matter over
Antimatter that we see today.
Last January, a team of
150 scientists from Italy and the United States started CUORE, a
Five-year experiment to determine if neutrinos are
in fact their own antiparticles.
CUORE tries to do this
Discovery of an extremely rare event called "neutrino-free"
Double-beta decay. "Over time, two neutrinos will naturally decay
in two protons, two electrons and two antineutrinos; Anyway, if
Neutrinos are their own antiparticles, then very occasionally the two
Antineutrinos cancel each other out in a "neutrino-less decay".
Neutrino decay can be
observed in materials such as tellurium, but is a neutrinolose decay
an event that is so rare that it occurs only once in a tellurium atom
several trillion (million billion) years; even then, the
The signature of the decay is very hard to see because it exists
an energy peak of only 2.4 MeV – less than a thousandth
The CUORE experiment therefore takes place as far away as possible from all
Interference, placed in a laboratory under almost a mile of solid
Rock, and in what scientists have to be calculated
"The coldest cubic meter in the universe," a refrigerator style
Device that cools its interiors to only seven thousand degrees
above absolute zero. In the cooling area 988 tellurium
Dioxidkristalle (total about 100 trillion tellurium atoms) are
very carefully looking for the tiny temperature peak that monitors
would signify a neutrinoless decay.
Two months into the
Experiment, the scientists have reported that they have not yet discovered
such an event, and as a result, they concluded that the event is occurring
Of course, at most once every 10 million years in a single
The researchers predict
they should be able to observe at least five neutrinolose decays
the next five years, in a discovery that would not just confirm that
Neutrinos are their own antiparticles, but they also violate the standard
Model Law for the Preservation of the Lepton Number
The experiment does not recognize the desired event, the next is the experiment
Generation, called CUPID, will take its place by giving it a straight
larger number of atoms; should this second experiment also fail,
A final iteration could give a definitive answer to the question.
we will not see it within 10 to 15 years if nature does not choose it
something really strange, the neutrino is most likely not his own
Antiparticles, "says CUORE team member Lindley Winslow. Particle
Physics tells you there is not much room for maneuver
Neutrino, to still be his own antiparticle, and not to have for you
Have seen it. There are not many places to hide. "
The paper with the study was published in the journal this week
Physical Review Letters .
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