Neutrinos Definition and 331 Threads

Hi all! This question concerns flavour changing oscillations. Let's narrow it down to the neutrino case, where we have additionally the violation of lepton numbers. So electron and muon neutrinos naturally follow the relativistic Dirac equation: (p\!\!\!/ + m_e ) \nu_e = 0 and (p\!\!\!/ +...

This paper, http://arxiv.org/abs/1404.6160, advances the case for sterile neutrinos as a dark matter candidate.

What are the lowest energy transmutation caused by a neutrino and an antineutrino respectively?

All the Feynman diagrams I have seen so far for a neutron colliding with a neutrino have a w+ with an arrow from the neutrino to the neutron. Would it not also be possible with a W- leaving the neutron taking away negative charge for it to become a positive proton or is there some quantum rule...

Is there something like a "neutrino spectrum"?. Would it be analog to light spectrum?. Sorry for the ignorance, just curious. AGZ

Greetings, The IceCube neutrino detector array in the antartic is a cubic kilometer and has deceted about 28 neutrinos from outside the solar system. So the resolution is almost nothing. I am wondering how large a detector array would have to be to serve as a telescope to observe what I am...

I came across a worked example question in a particle physics book this morning that had a beam of neutrinos of energy 2.3MeV incident on a lead target. The point of the question was calculating the thickness of lead needed to reduce the beam intensity by a certain fraction - and the solution...

Various astrophysical processes produce antineutrinos, which then fly off into outer space. I assume there are pretty accurate estimates of the production rates. I can imagine three possible fates for such an antineutrino: (1) annihilating with a neutrino, (2) interacting with baryonic matter...

This question is probably very over-simplistic, however: if neutrinos are majorana particles, which are their own antiparticles, how could they still be CP violating? I don't understand precisely how this would work, but physicists I have spoken to said that neutrinos being majorana could...

Current main stream theory is neutrinos must have mass. Recent paper claims its on the order of 5 to 50 eV (I've forgotten exactly). So, they must be slowed down (as well as sped up) by gravitational interaction, correct? As well as the expansion of space. Hence they must be attracted "just...

If a neutrino beam passes through an optics lens in principle does the matter in the lens focus the neutrino beam granted it may be ridiculously small amount? If the lens were instead made of compressed matter of nuclear densities would the answer change much? Thanks for any help!

I have a similar question. Since the neutrino's has a rest mass I can observe it in a SR frame where it is at rest. Now if I measure the mass (say by energy absorption inside a light trap) at one time. To the degree necessary to distinguish it's state from the other neutrino states I get a...

I'm currently doing a report on 'Neutrino Oscillations and mass'. I have spent today just trying to raise my understanding of Neutrinos/leptons and terminology to do with them. I'm still quite confused and still not entirely sure what in particular about a neutrino is oscillating. Is it the...

Homework Statement Prove the relationship between the momentum of the neutrino or nucleon in an elastic scattering of them in the center of mass frame is p'^{2}=m_{1}E_{2}/2, where p' is the momentum of the neutrino or nucleon in the center of mass frame, m_{1} is the mass of the nucleon...

Hello, I'm currently in my last year of high school and I'm doing a project about the higgs particle decaying to two photons. I am using HYPATIA to analyse ATLAS events. When a higgs boson decays into two photons, you can see activity in the electromagnetic calorimeter without seeing a track...

Quantifying an "Off-axis" Neutrinos (probability and intensity) Considering the modelling of a high energy proton beam neutrino experiment. I have questions concerning the scattering of neutrinos from the axis of the proton beam. I understand that a muon beam (derived from a proton beam)...

Where have all the neutrinos gone? I’m no cosmologist, and my understanding of nuclear physics is pretty primitive. I haven’t yet found answers to some simple questions: Where have all the neutrinos created so prolifically by stars over the last 13,8 billion years gone? Are they still...

It could be useful to group some references for this: http://arxiv.org/pdf/1204.5379v1.pdf (Light Sterile Neutrinos: A White Paper) http://arxiv.org/abs/arXiv:1311.0282 (Sterile neutrino dark matter bounds from galaxies of the Local Group) I'd like some more references. Please share any good...

Hi people, I have the following question: First, here is a concise statement of the major neutrino speed measurements: http://en.wikipedia.org/wiki/Measurements_of_neutrino_speed As you can see all of them show that the speed of neutrino is within the speed of light, when taken into...

Hi everyone, I am doing a final project on the title " fundamentals of neutrino physics". I wanted to raise some issues with neutrino which makes it the possible way to the physics beyond standard model. I am myself doing some research on these topics but at some points the math bugs me out...

http://arxiv-web3.library.cornell.edu/abs/1311.5238 "Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube Detector" Judging from newspaper accounts, a lot of physicists seem very excited by this paper. Can anyone offer any further insight? Are the present results hard to...

I can't seem to find the mass of an anti electron neutrino in MeV. I found that in beta radiation one down quark breaks into an up quark, an electron, and an anti electron neutrino. The mass in MeV of a down quark is 4.8, the mass of an up quark is 2.4 MeV, the mass in MeV of an electron is...

Hello everyone This is my first post and I am interested in the question about neutrinos... I have many questions that I would love to have answered but I'll stick to the question of whether they can travel faster than light or not... ( please bear with me as I am returning to physics after a...

neutrinos -- what is their mass when they travel so close c? I understand that neutrinos move at very near the speed of light and that they have a very small amount of mass. This being true, why do they not have a great deal of mass at that speed?

The IceCube detector in the deep ice at the south pole has seen two instances of 1015 eV neutrinos. These are said to be the highest energy neutrinos so far seen. http://resonaances.blogspot.com/2013/09/storm-in-ice-cube.html What process could have launched such high energy neutrinos? It has...

Hi, this is probably pretty simple but it's puzzling me... In neutrino oscillation, you produce and detect neutrinos with a specific flavour (e,μ,τ) but they travel as mass eigenstates (1,2,3). The flavour eigenstates are just linear superpositions of mass eigenstates: nu_e = U_e1 nu_1 +...

If neutrinos were massless, they would have to travel at c. But now we know they have mass, so they must travel at speeds less than c. But (all?) other massive particles can be brought to rest. Why not neutrinos? Is there a theoretical reason that forbids it?

Hi, just as an introduction, my amateur knowledge in particle physics reaches to the Standard Model (just to put a number, 70 or 80 percent of its mathematical content understood) and then I understand the basic problems of physics beyond SM in a conceptual but not mathematical way. So I've...

As a byproduct of the last slides on Koide, I have done a semilogx plot of the standard model in latex with the tikz and pfgplots packages, and it can be generically useful to everyone. So here is the gist: https://gist.github.com/arivero/e74ad3848290845de5ca I call this picture the "small...

Note: this is a re-post because my initial post had problems, no one could reply to it. Ok this is my second in the series about dark matter. In a previous thread I asked where is dark matter https://www.physicsforums.com/threads/where-on-earth-is-dark-matter.764693/ The main response to my...

In How A Supernova Explodes, Scientific American, by Bethe and Brown, there is this passage. Wow 10% of the mass equivalent of the neutron star. What an amazing number. But as I see it, the number of neutrinos should equal the number of protons in the pre collapse core material (which...

Looking at Nucl.Phys. B194 (1982) 422 I read "In 1972 there were two neutrinos and they were both massless. Today we have three and perhaps all of them have mass. " Hey, 1981 and neutrinos have mass? I was not even in the university. And in all the textbooks the neutrino was massless...

So in beta decay I know a neutron can decay into, proton, electron and antineutrino (Or, neutrino, since they're both the same?) But anyhow, regardless of the neutrino, in neutron stars electron degeneracy doesn't hold and electrons combine with photons to form neutrons. But isn't that...

Hello all, I have a few questions and a few thoughts I think I understand that according to einsteins theory of relativity, wavelengths can be perceived differently when traveling at different velocities comparatively to when it was emitted. i.e. if something traveling close to the speed...

hello everyone I have a question , that is like a story " I talking with my friend about Neutrino and ... " I had written about it at wikipedia and they said that the speed of Neutrino not more than Photons , but I had read that they are faster than Photons speed. which one is true?! I am...

I wasn't really expecting the results to collapse permanently into the "faster than light" state, but I found the whole process to be interesting so I always kept myself updated on the controversy. As I recall, they spent months trying to find an error in their measurements before publishing...

I understand that Higgs mechanism “gives” mass to particles in QM sense. My first question is, why it also gives mass in GR sense, bending space-time? Of course, I don’t expect an answer now as it is definitely a TOE/Quantum gravity territory. However, let me rephrase my question in a narrower...

I'm a little confused. During Beta(-) radiation, a neutron becomes a proton due to a down quark becoming an up quark. When this happens, a W(-) boson is emitted which almost immediately decays into an electron and an electron antineutrino. A W(+) boson, similarly, is emitted when a down quark...

So did anybody have figured out why did OPERA experiment failed?? Does anyone know why neutrinos appear to travel FTL??

How W- boson decay into electron and anti neutrino?

Homework Statement For the following reactions draw Feynman diagrams, clearly labelling all the quarks, leptons and exchanged particles and stating the type of interaction involved (if more than one interaction could be involved give the most likely): (i) ##\pi^0 \to \gamma + \gamma##...

Homework Statement Hello Guys :) I have been studying neutrinos this term in physics and have been trying to calculate the neutrino flux on earth. I have found an equation but I am just unsure about what the variables in the equation stand for. Homework Equations F = N/(A t) = E/(A...

Why do neutrinos and anti-neutrinos oscillate differently? http://www.forbes.com/sites/alexknapp/2012/12/31/anti-neutrinos-may-hold-the-key-to-solving-physics-mystery/ I realize this is just a recent discovery, but are there any speculative explanations? How does this discovery impact...

since we don't know its mass,, is it by looking at the lepton by products?

I’m thinking as I go, here, so I am numbering points for ease of reference, correction etc. 1. Neutrinos (excluding the anti- and sterile varieties) come in three flavours. 2. It is known that neutrinos have mass. 3. The masses of individual neutrinos are not known precisely. 4...

Hi I'm just curious, what role does neutrinos play in the universe? I mean protons an electrons and neutrons make up the atom, quarks make up protons and such. But neutrinos? Barely heard anything except that they are barely interacting with anything, and that they are a "waste product"...

Neutrinos faster than light SOLVED ? Heya all, I was thinking about the neutrinos going faster than light (yes, it has been some time ago), and thought, on Einstein's side, that they couldn't have. So I conjured something up. What if the clocks they used were not on equal, because of the...

The title fairly states the question. I remember the big deal being made over our slightly (possibly) faster-than-light neutrinos, but then, at least from all popular media, it completely faded out. Whatever became of this? I assume things are inconclusive so far, and it would be even bigger...

I know that they didn't actually go faster than than speed of light but I'm not sure what went wrong. I've heard lots of possibilities but i don't know which is right

Where are the following particles found: Electron neutrino? Muon neutrino? Tau neutrino? Muon? Tau?