Nature News: Neutrinos like to keep to themselves. These ghostly particles are so reluctant to interact with ordinary matter that billions zip harmlessly through each person every day, and it takes giant, specialized detectors to capture even a handful of them. Now astronomers are finding hints of an even more elusive type of neutrino, one so shy that it could never be detected directly: the sterile neutrino.
"The question of sterile neutrinos is absolutely crucial for nuclear particle physics and astrophysics."
For more than a decade, this subatomic spectre has intrigued theorists and experimenters, but experimental efforts have had trouble catching them. Now, two observations in space—one in microwaves and the other in x rays—are raising hopes again.
I find this article fascinating. Such neutrinos would result in four species of neutrinos instead of the 3 Standard Model flavors and might indeed account for at least some of the Dark Matter within the universe.
Although these sterile neutrinos would not even interact via the weak force; however, they would possess inertial mass and non-zero positive energy and so they would react to gravitational fields and could contribute to the gravitational self attraction that the real mass-energy portion of the universe feels with respect to itself.
If the sterile neutrino exists, I am personally interested in any possibility that there might exist another lepton within the electron family, and perhaps two additional members of the quark family, along with 4 associated anti-particles for a total of 8 additional particles.
Remember, the electron neutrino is classified in a first generation of particles including the electron and the up quark and the down quark. Since these particles come in antimatter versions as well, this generation includes a total of 8 particles.
The muon neutrino is classified in a second generation of particles including the muon and the charmed quark and the strange quark. Since these particles come in antimatter versions as well, this generation includes a total of 8 particles.
The tau neutrino is classified in a third generation of particles including the tauon and the top quark and the bottom quark. Since these particles come in antimatter versions as well, this generation includes a total of 8 particles.
Nature loves symmetries, and so perhaps there exist three species of sterile neutrinos, one for the electron family, one for the muon family, and one for the tauon family.
Om the other hand, if a fourth flavor of neutrino exists such as a sterile neutrino that cannot be grouped with the three generations of known standard model fermions, then perhaps we can consider whether a 5th neutrino exists, along with an additional cold lepton and perhaps along with two additional quarks thus resulting in a total of 5 charged leptons and 5 charged antileptons, and 10 quarks and 10 antiquarks.
I would through one heck of an outdoor barbecue party if another generation or two of quarks are discovered. Mainstream QCD theorists do not expect this to happen, but as I like to say, never say never
I enjoy science, especially physics. From what i understand from http://www.pdfok.com/sterile-neutrinos , if an object’s velocity is increased then its mass is too. Does this mean that the object’s gravitational force increases? If so, when protons are accelerated to c(99.9/100), do the particles create gravitational fluctuations, inside of the accelerator, that can be observed?
David, for more on sterile neutrinos, see today’s Physics Update.
Hi David;
That is an interesting question. One can go to extremes and ask whether or not a proton accelerated to the Planck Energy would become a mini-blackhole based on it relativistic energy. Perhaps due to Lorentz length contraction of the particle in its direction of travel, it would effectively become a black hole along the axis parallel to its velocity vector. However, if this happened before the onset of a black hole state in the directions orthogonal to its velocity vector, we might risk producing a naked singularity, a situation that could have disasterous consequences.
This is extremely interesting topic for me. I’ve found some information at wikipedia and read a couple of articles on your website. Are there any books that cover this phenomenon?
This is a very interesting article. I am fond of nuclear particle physics and follow what is new in this field regularly. I like to read the works by Brian Cox, the University Manchester particle physicist. Recently I’ve found out that he is even a nice musician. I managed to find some of his songs at music search http://www.mp3hounddog.com . I was surprised but his songs are not related to science. Well, for me it was a great news that people could be so broad-minded and achieve success in music and in science.