Neutrinos Definition and 328 Threads

I was reading about Gargamelle experiment from the 1970s. It is supposed to be the experiment that proved weak neutral currents (leading to the discovery of the Z boson). However as I understand it, it was from the interaction of neutrinos with electrons or neutrinos with nucleons. I was...

Number of neutrinos detected per kg of water = 12/3*10^6 kg = 4*10^-6 neutrinos Neutrinos detected by 1 eyeball = 4*10^-6 neutrinos * 0.01kg = 4*10^-8 neutrinos I am not sure how to scale this to get 400 neutrinos. I did try multiple ways but either ended up with 3.69*10^9 or 4*10^-8 neutrinos...

Suppose there was a 4th generation of neutrino (X, say) with mass m ~ 1 keV. The other three neutrino generations decouple at T ~ 1 MeV and are not heated during ##e^{\pm}## annihilation (whereas the plasma is heated, leading to a bookwork ##T_{\nu}/T_{\gamma}## factor due to conservation of...

Would it be possible to eventually have structures made from neutrinos somewhere in the universe, as it is indicated in this question (https://physics.stackexchange.com/questions/80390/are-neutrino-stars-theoretically-possible), like halos of neutrino gas surrounding the center of galaxies...

At what half-life duration, if any, does the likelihood of a neutrino collision within a sample of radionuclide atoms exceed the likelihood of a decay event in those atoms over the same time period? Can they be efficiently excluded by their reaction products, or are they meaningfully difficult...

[Moderator's note: Spin-off from previous thread due to topic change.] A Majorana mass term is completely different physics from a neutrino oscillating to an antineutrino.

This Wikipedia particle says that neutrinos are generated: https://en.wikipedia.org/wiki/Supernova But this article (about SN1987A) seems to say that both neutrinos & antineutrinos were detected: https://en.wikipedia.org/wiki/SN_1987A

I'm reviewing history of subatomic physics. By 1931AD the nuclear physics community had decided to propose the neutrino because they couldn't explain beta decay without it. Alpha and Gamma decays were more confined wrt the energy they would extract from the nucleus i.e. they had energy bands. By...

If I put this in technically correct terms, to enable a local symmetry related to electron phase change, we need to introduce a spin 1 field which is identified as electromagnetic field. Yet there are other spin 1/2 particles. Say, what about neutrino? As it does not couple with electromagnetic...

while the photon travels at light speed and a neutrino travel at just below light speed why then are photons stopped by an object and the neutrino can past through?

How do we know that cold neutrinos do not make up 100% or a large percentage of the dark matter content in the universe? In my mind, the only way to prove that dark matter is not simply cold neutrinos would be to measure the density of cold neutrinos in the universe and then calculate the...

(not sure if this is more suitable in the beyond standard model and/or this has been discussed previously in a recent time, I did some searching and could not find any) "Search for electron-neutrino transitions to sterile states in the BEST experiment"...

Hi, I would like to ask question about atmospheric electron neutrinos. It is known that atmospheric electron neutrinos originate from the decay of muon in the atmosphere, but we can also calculate that muon with energy more than 10 GeV is able to penetrate about 100 km, so it does not decay and...

what about Modified Newtonian Dynamics + dark matter both right and both correct Are sterile neutrinos consistent with clusters, the CMB and MOND? Garry W. Angus arXiv:0805.4014 [ If no sterile neutrinos then Modified Newtonian Dynamics + primordial black holes Primordial Black Holes...

Can someone please explain the four classes of fundamental particles? (Just the basics) I came here because I never learned any chem or physics in school so please explain like I’m five :)

https://journals.aps.org/prd/pdf/10.1103/PhysRevD.104.L091101 And here is the pop science summary: https://www.sciencealert.com/for-the-first-time-neutrinos-may-have-been-detected-at-the-large-hadron-collider Which results can be expected?

Summary:: Hello I am a writer and presently working on treatment for a science-fiction story. So I am not a scientist, just a neophyte interested in science and wanting to write a fiction that would not be too far-fetched and that would make some sense for everyone, including the scientific...

There was a lot of kerfuffle a decade ago about neutrinos possibly exceeding the speed of light, A re-analysis of events debunked this back in 2012 I believe, but I don't know if the issue is conclusively settled. Has there been any re-confirmation of the speed of neutrinos in any paper later...

Hello, When you have a beta decay you get the typical continuos spectrum representing counts against the kinetic energy of the electron. But what's the shape and how I get the spectrum of the kinetic energy of the neutrinos? Thanks

I had thought that cosmic rays were protons, but this NY Times article seems to say that cosmic rays are neutrinos: https://www.nytimes.com/2021/03/30/science/neutrinos-lake-baikal.html

For the first part I thought you'd have either, p + anti-v -> n + e+ and n + v -> p + e-, but I thought it'd probably be the latter as it's a 'normal' neutrino not an anti neutrino? But do I need to include the actual elements in the equation? For the second part I have multiplied the density...

Merry Christmas! Neutrinos are mysterious. I just blogged about some of the big open questions involving neutrinos: Neutrino puzzles. In brief, nontechnical terms they are these: What is the correct theory of neutrinos? Why are they almost but not quite massless? Do all three known...

Stable nuclei have radii that are approximately given by the formula: R = r0_A^1/3 Where r0 = 1.25 × 10−15m and A is the atomic mass number. In many experiments of interest to modern particle physics, beams of neutrinos scatter from nucleons within the nucleus. Even though the nucleus is at...

Hello! I am a bit confused about neutrinos in the standard model. The vertex of the weak interaction charged current, implies that any neutrino interacting through the charged current must be left handed. However the neutral current allows coupling to the right handed particles, too (and we see...

Hello! I don't know much about this topic so I am sorry if my question is silly. As far as I understand if neutrinos are Majorana particles, one consequence is that neutrinos are their own antiparticles. This can be observed, for example, in neutrinoless double beta decay. However, if we take...

In the Wikipedia article for CvB, it mentions the following: "The above discussion is valid for massless neutrinos, which are always relativistic. For neutrinos with a non-zero rest mass, the description in terms of a temperature is no longer appropriate after they become non-relativistic; i.e...

If neutrinos are majorana particles does this mean that lepton number is not conserved in particle reactions? And I only noticed neutrinos are only produced when the decay of a particle to some other particles is carried by the W bosons ( weak interaction ). Is it possible the weak interaction...

https://www.theonion.com/physicists-hail-major-breakthrough-after-discovering-ne-1844363984 "Confirming the search for the mysterious Godfather particle was finally over, physicists at the University of Chicago hailed what they call a major breakthrough Monday after discovering neutrinos are...

Assuming that this sphere has a radius of 50kpc, I've converted to m (1.543e21) and plugged into the area equation for a total area of 2.992e43 m^2. From here I've talked myself into circles, and I honestly don't know where to go next. Any help or guidance would be greatly appreciated!

Quoting from IceCube Observatory's webpage, (Emphasis added.) The paper, available on arXiv, has been submitted to The Astrophysical Journal. I haven't read through the paper yet, but if this detection cannot be explained by the Standard Model, what could possibly be the cause? Is there any...

I was looking into neutrinos and found that a man named Ettore Majorana proposed neutrinos and antineutrinos are the same thing. If this could be true, antineutrinos emitted during double beta decay could annihilate one another and vanish. However, this would violate lepton number conservation...

Double-beta decay will emit two neutrinos. But, are they simultaneously released or separated?

As far as I know neutrinos are normally fast/ connected with a velocity close to the speed of light. This seems to be characteristic. Can neutrinos also be in a state of slowness or rest? If yes, has there ever been an indirect observation of such cases?

Summary: Neutrino A neutrino smashes into an atom and creates an electron - why doesn't the neutrino pass through the atom?

Hello! I am a bit confused about the non-existence of right handed chiral neutrinos. Is this and experimental fact, or it follows from the theory directly? And if it is experimental, how can one test that? Can the chirality be measured? Thank you!

I'm puzzled why, now that we know that neutrinos have mass, we still read that there are only left-handed neutrinos, as far as we know. I understand that right-handed neutrinos do not interact by the weak force, so we would not detect them. My question is why we read that they might not /...

At very high energies Earth absorbs a relevant fraction of neutrinos passing through it. Experiments receive more of these neutrinos from above than from below and the difference depends on the mass of Earth. So why not measure it? Neutrino tomography of Earth The uncertainty is very large, of...

Homework Statement I'm trying to solve problem 3 from http://www.ictp-saifr.org/wp-content/uploads/2018/07/hw_ICTP-SAIFR-2.pdf The problem is as follows: Assume that solar neutrinos arrive at the surface of the Earth in the ##\left| \nu_2 \right>## state (a mass eigenstate). Assume this...

Homework Statement Consider solar neutrinos of energy 1 MeV (EDIT: 10 MeV not 1 MeV) which are formed at the center of the sun in the ##\nu_2## eigenstate. What fraction of it do you expect to arrive at Earth as ##\nu_\mu## and what fraction as ##\nu_\tau##? Assume that it evolves adiabaticaly...

https://arxiv.org/abs/1810.01000 MiniBooNE, MINOS+ and IceCube data imply a baroque neutrino sector Jiajun Liao, Danny Marfatia, Kerry Whisnant (Submitted on 1 Oct 2018) The 4.8σ anomaly in MiniBooNE data cannot be reconciled with MINOS+ and IceCube data within the vanilla framework of neutrino...

Do black holes accumulate neutrinos ? Do the neutrinos that fall in, decay in some way , maybe interact with the condensed matter, or just stay "parked" in perpetual loops ?

First question: Within experimental error all measurements of neutrino and light speed in vacuum are consistent with c, but one way speed measurement of light is well proscribed, so is a one way speed measurement of neutrinos also proscribed? I have more questions, but maybe just clarify this...

Read more at: https://phys.org/news/2018-07-century-old-riddle-resolveda-blazar-source.html and a second article from Ars Technica: https://arstechnica.com/science/2018/07/icecube-spots-a-neutrino-source-a-black-hole-jet-pointed-at-earth/ showing how multi-messenger astronomy is...

Bee Hossenfelder's blog has a discussion: http://backreaction.blogspot.com/ Preprint: https://arxiv.org/abs/1805.12028 New evidence in the search for the 'sterile' neutrino. Can someone comment on this please. @mfb

Why is there an assumption that if neutrinos didn't have mass they would move at the speed of light? and how does the fact they oscillate prove they have mass?

My question is what is the actual purpose for the emission of neutrinos and antineutrinos during the beta + and beta - decay of an atom respectively?

I`ve spent some time reading about the baryon asymmetry and the Sakharov`s conditions, and there some things I didn't exactly get: 1. Interactions out of thermal equilibrium: isn't it trivial? our universe is expanding so, of course, it out of equilibrium. 2. CP violation: I`ve read that Cronin...

Background The Standard Model conserves baryon number, which is equal to (quarks divided by three) minus (anti-quarks divided by three) and lepton number, which is equal to leptons minus antileptons, separately, except in sphaleron processes which conserve B-L, but not B or L separately. There...

What particles(s) can pass through hundreds of miles of the Earth? Is it only neutrinos, or is there some other particle(s)?

Would neutrinos emitted in the distant and early universe be slowed enough to become thermal neutrinos? Could these be detected?