Neutrinos Definition and 329 Threads

Neutrinos can pass through solid objects like the Earth easily, and a light-year of lead would only stop half of them from passing through. What about something very dense like a white drawf or neutron star? How readily can neutrinos penetrate that? What % flux reduction would be achievable...

I have a two component Weyl spinor transforming as \psi \rightarrow M \psi where M is an SL(2) matrix which represents a Lorentz transformation. Suppose another spinor \chi also transforms the same way \chi \rightarrow M \chi. I can write a Lorentz invariant term \psi^T (-i\sigma^2) \chi where...

Posted in quantum physics, maybe wrong session. Neutrinos are massive particles, so that i would expect that their helicity depends on coordinate system. Why are they lefthanded at all times? I heard that in decays righthanded neutrinos are suppressed by a factor (1-beta)/2, but i don't know...

I am puzzled by the "always lefthanded" neutrinos. In the beta-decay process a W-boson decays to an electron and an anti-neutrino, which must have same spin direction in order to comply with spin conservation. In the deay of a pion to a muon and an anti-muon neutrino these two particles must...

What can Neutrinos tell us about time?

Hi everyone, I have a few queries about neutrinos. I have recently read that there are 3 generations of neutrinos, namely the electron neutrino, the muon neutrino and the tau neutrino. Q1: Why are they all massive particles and is it true that it is more favourable to go from muon neutrino to...

Wen local bosonic emergent string net model states he can give rise to electrons and photons, quarks and gluons but not chiral fermions. I know neutrinos are chiral. Any other fermions? If he can provide an explanation for masses and mixing angles for all SM particles except neutrinos...

Does anyone have an up-to-date reference for the best value of \Omega_{\nu}, given our current understanding of neutrino masses? Dodelson's cosmology book has \Omega_{\nu}\approx 10^{-3}, but something more recent would be nice.

Could dark matter be neutrinos? I'm wondering, neutrinos are weakly interacting, but they do respond to gravity. So has anyone calculated how far out of a galaxy a typical galactiaclly produced neutrino would travel before coming back into the galaxy? Are some galactically produced neutrinos...

Neutrinos have mass... insignificant mass, we are told, as their speed is so near that of light we can't even observe the difference. On the other hand, there are a lot of them. Every year the Sun produces something like half a tredecillion neutrinos, if my math is right. Depending on the mass...

Neutrinos are almost massless, travel close to the speed of light, and pass through matter almost undisturbed. Photons, on the other hand, have no mass, travel at the speed of light, yet are absorbed and/or reflected even by fairly sparse matter such as gasses. Why?

Hi, I was wondering: why in hydrogen fusion are neutrinos ejected? why in fission does the neutron actually knock over neutrons out of atoms the nucleon are held together in the nuceus by nuclear forces which over power electrostatic forces. But what actually generates these forces? Are...

Context: In beta-decay the kinetic energy of the electron is continuous. This led Pauli to the conclusion, that the pre-1930 picture (beta-decay = neutron -> proton + electron) is incorrect and he assumed that a third particle (the neutrino) is taking part. Question: Why would the following...

All neutrinos are left handed and all anti neutrinos are right handed.so,it should be lorentz invariant and travel at speed of light. if it travels at c,then it is massless. but, neutrino oscillation requires mass? why there is contradiction?

Hey guys, I have a question for the particle physicists from an astronomer's point of view. First of all, with regard to the IceCube neutrino telescope, one of its principle goals is to find cosmic sources of neutrinos, but I want to know how the telescope will be able to distinguish the...

Hey guys. Just before you read this, let it be known that I am merely a 16 year old, and so these are basically ideas from one who is not as educated in the field of astrophysics as others, so forgive me if this concept may sound utterly rubbish to you. Ok. So here it is. Neutrinos. There...

I just saw a documentary about the detection of neutrinos, and the first detection using chlorine atoms was able to detect only electron neutrinos which accounted for about 1/3 of the total number of neutrinos predicted. The muon and tau neutrinos weren't able to be detected by that method. My...

Homework Statement http://img517.imageshack.us/img517/8112/neutrinosll8.jpg Homework Equations The Attempt at a Solution I was able to express the time delay as D(1-\frac{1}{1-\delta}). However, I don't have a lot of experience using Taylor series and did not use one to obtain...

Why don't the photon and the neutrinos couple to the higgs field? Is there any associated charge which determines which particles couple to the Higgs field?

Hi, I've been trying to find information on neutrinos and the way that they are experimentally proven to exist. Most of the sites I've found state that neutrinos are indirectly proven to exist by experiments (conservation of energy, mass, etc.) Have there been any experiments that show direct...

Hello, I am hunting informations about new physics. I am starting a phd in theoretical high energy physics. because of the funding (the part that gives nightmares) the subject HAS TO BE related to neutrino physics (in fact I am in a leading group in this field). So, what do you think (personal...

PBS “Ghost Particle” neutrinos showing Standard Model wrong Tonight and tomorrow (Sunday), PBS television is rebroadcasting “The Ghost Particle” on the neutrino work by John McCall and Ray Davis that showed the Standard Model Theory was wrong and made incorrect predictions about neutrinos...

Hello ! I will probably start a phd thesis about neutrinos (theoretical/phenomenological aspect) on october ... I need some hints about references for those among you who know the subject well. Thanks in advance.

If the sun produces so many neutrinos from fusion, then I would assume that so do all other fusion stars, yet why is it that our detectors detect only the number of neutrinos that would be expected to be produced from our sun? If neutrinos travel at nearly the speed of light and barely ever...

Sorry, I am just a newbie here, but I hope I can ask some basic questions about neutrinos that I haven't been able to find in books? My first question for starters... then I will see how it goes. If science has only been able to detect a few neutrinos, how do we know for certain that...

A NASA satellite has uncovered evidence that a sea of neutrinos, almost weightless elementary particles that zip around at nearly the speed of light, permeates the universe. The discovery is part of a treasure trove of findings gleaned from data collected by the Wilkinson Anisotropy Probe...

[SOLVED] Evidence for the existence of neutrinos. [solved]

Does that fact that it has been shown that neutrinos have mass in any way imply that there must be right handed neutrinos?

First let me relate that my understanding of quantum physics is rather shallow. What I'm looking for below is not some abstract mathematically response but rather a more spatially conceptual answer. Theory predicts every second supposedly 70 billion solar neutrinos pass through every...

What distinguishes the neutrinos? Assuming Neutrinos are massless What then distinguishes the 3 neutrinos experimentally. WHy 3 neutrinos were proposed theoretically in the fisrt place? Whats the justification behind introducing 3 neutrinos? Plz don't say that because there are 6 quarks...

what is the best estimates on the number of neutrinos in nature?

Hi. I am curious about the following nuclear reaction: \nu_{e} + ^{71}_{31}Ga \rightarrow ^{71}_{32}Ge + e^{-}. Can anyone explain to me why this reaction has an energy threshold of approximatly 0.23 MeV? How does one calculate the minimum energy of the neutrino for this reaction to take...

How can cosmology set an upper limit on the rest mass of neutrinos if we know that the universe contains about 450 neutrinos per cubic centimeter?

Does the Dirac equation predicts the fact that there are no right handed neutrinos?

Hi, i just completed my paper looking the posibility that neutrinos feel an additional force added to the standard model. The force is based upon U(1) just like the electromagnetic force, but left and right handed particles have opposite charges. The paper is available below, and at my web...

Hi, We were told in a very-elementary elementary particles course, that a neutral current event was first observed in the following process: \bar{\nu}_\mu + n \longrightarrow \bar{\nu}_\mu + X were X is "something other than muon" (n was a neutron). I thought about it, and I don't know how X...

On page 3 of the following pdf: http://pdg.lbl.gov/2005/reviews/numixrpp.pdf the paragraph after equation 13.12, there's a line that says: "Thus, if U is not real, the neutrino... When CPT holds, any difference between these probabilities indicates a violation of CP invariance." I don't...

Hi guys, I have a basic question about neutrinos. Since it is now supposed from both cosmological and particle physics observations that neutrinos have a small rest mass, what are the lowest energy (and hence lowest speed) neutrinos we can/have observed? Since they are so weakly interacting...

I just read that the mystery of the "missing solar Neutrinos" has been solved. That is, the "missing" stuff is converted to Muon & Tau Neutrinos (which have been detected at the SNO). I'm confused ... If Solar Neutrinos are very "non-interactive", then how do enough of them get converted...

If Neutrinos have mass, What is the velocity of neutrinos, can they "slow down" due to gravity, and do their acquire their mass from interactions with the HIggs field?

For my diploma thesis I must provide a calculation that reproduces the results given on page 46 of the paper hep-ph/0309342 . For those who do not want to look it up, I briefly explain what it is about: It concerns the two-body scattering processes (1) N + V => L + H, (2) N + L => V + H, (3) N...

Hi everyone, I just have a question regarding a project I'm doing at the moment. I decided to write about the detection of neutrinos, and hence have to explain the Cerenkov effect which is used in the water detectors. What I can't understand is that, from what I've read so far, the Cerenkov...

Hello, I recently read about neutrinos having mass > 0. (http://news.bbc.co.uk/1/hi/sci/tech/4862112.stm) , but also they travel at the speed of light. How can it be possible? If they have mass, their mass should increase with the velocity, and at the speed of light according to special...

neutrinos are like electrons but not charged. its partner in the subatomic universe. no charge and subsiquently no mass. http://www.ps.uci.edu/~superk/neutrino.html part of the electromagnetic spectrum?? gamma rays are also electrons, no charge and no significant mass. part of the...

I am new to these particles called neutrinos but I was wondering why are they called the "partners" of electrons?

I'd like to examine the experimental side for a moment, not the theoretical. Would the non-differential (after very long distances and time, and taking into account the different production mechanisms) in the arrival of light and neutrinos from supernova 1987a constitute strong experimental...

since presumably electrons, photons, gravitons, and neutrinos are just vibrations of a string?

Could we somehow develope a neutrino telephone? Since they pass through everything, you wouldn't have to deal with obstructions like buildings which are often an issue with cell phones.

I am wondering how to calculate how far a neutrino would have to pass through a substance for it to have a probability P of interacting at least once. Water, for instance, has a density of 1 g / cm^3; using Avogadro's number I think this means that there is about 6.02 x 10^29 protons and/or...

Is there that much space in between all the electrons, protons, and neutron that this is likely? The only explanation that I can think of is that the neutrinos are in a different region of n-dimensional space-time and the fact that they pass through the Earth is merely a geometric illusion...