# Tag Info

## New answers tagged neutrinos

1

Neutrino can interact only by exchange of electroweak boson. So in each reaction with neutrino $W^\pm$ or $Z$ bosons must be involved. Also, Standard Model neutrino is assumed to be massless, so there is defined handedness: neutrino is left-handed and antineutrino is right-handed. Consequence of it is that left-handed neutrino will interact only with ...

1

In the reaction that you ask about the exchange boson is space-like (meaning that for that particle $E^2 - (pc)^2$ takes on a negative value. In cases like that there is no unique way to decide if you have a $W^-$ going from the nucleon to the lepton or a $W^+$ going from the lepton to the nucleon, and the drawing is usually annotated only with a $W$. ...

1

Yes, and indeed this was how the original solar neutrino detection experiment worked. It used the reaction: $$\nu_e + ^{37}\text{Cl} \rightarrow ^{37}\text{Ar} + e$$ The neutrino interacts with a neutron and turns it into a proton and electron.

3

The cause for neutrino oscillations is that the flavour eigenstates are not the same as the mass eigenstates. Therefore, once you know the flavour of a neutrino, i.e. whether it is a electron, muon, or tau neutrino, the mass is not well defined. And the other way around: Once you know the mass, the outcome of a flavour measuring experiment is uncertain. The ...

0

Look at the "bar" region of, e.g., NGC1300 and wonder whether you are seeing a neutrino star. If so it could be of greater mass than the visible galaxy so accounting for the linear g:r relationship in the bar region. If it is a Fermi condensate it could have a "liquid" surface at the tip of the bar with a lesser density tapering off in the spiral arms ...

0

No, it does not have all three flavors at the same time, it oscillates between flavors. A neutrino, because of lepton number conservation always starts with a fixed flavor, and then the probability of finding a specific flavor oscillates, let us take an electron neutrino from the link: : Electron neutrino oscillations, long range. Here and in the ...

1

In Peskin's introduction to quantum field theory, he talks about this in chapter 2, section 4 in a subsection titled causality, which is on page 27 in my book. He explains that yes, there is some non-zero probability that a particle will move faster than the speed of light. However, he shows any two local operators that are separated by a spacelike ...

8

The link about superluminal neutrions you cite is missing the fact that later on an error was discovered, and neutrinos do not, in fact, travel faster than light (see e.g. the Wikipedia article). To date, nothing that travels faster than light is known. The uncertainty principle does not "allow for the creation of virtual particles". The idea of such pairs ...

0

In its rest frame an electron is always equal parts left- and right-handed chirality.

3

Let's do a Back-of-the-Envelope calculation. It is typical for large-scale neutrino calorimeters (I have KamLAND specifically in mind because I worked on the project and know the detector reasonably well) to have an energy-scale uncertainty of a couple of percent at a few MeV energy. That's a systematic, and will effect all results more or less equally. ...

4

Neutrinos are notoriously difficult to detect . Have a look at this review paper : A core-collapse supernova will produce an enormous burst of neutrinos of all flavors in the few-tens-of-MeV range. Measurement of the flavor, time and energy structure of a nearby core-collapse neutrino burst will yield answers to many physics and astrophysics questions. ...

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