Neutrino Definition and 379 Threads

I was delight to learn that there was an event about 1 μs after the Big Bang when neutrinos decoupled, making them in principle observable. We of course don't have the technology to observe the event now, but the lecturer who informed me of this said it might be available 200 years from now...

In neutrino oscillation the probability a neutrino changing its flavour depends on the difference between the squares of the masses of the neutrino mass eigenstates. For example, the squared-mass difference between the mass states \nu_{1} and \nu_{2} is denoted \Delta m^2_{12} . However, I...

Just a quick question about notation really here. In neutrino oscillation we can calculate a probability of an oscillation occurring between two flavour eigenstates - invariably denoted P(\nu_{\alpha} \rightarrow \nu_{\beta}) . I've got some confusion about what happens to this when we apply...

How would a neutrino act in regards to a black hole? As in approaching, passing by or "colliding" with a black hole?

The ICARUS results evidence that neutrino moves at speed, not faster/slower, but same as c. The CERN results seem to be wrong due to some error in the equipment. http://arxiv.org/ftp/arxiv/papers/1203/1203.3433.pdf aren't the neutrinos expected to travel slightly slower than c? (due to...

I've read that the neutron has a magnetic moment because it is made of composite particles, namely 1 up and 2 down quarks. But why does the neutrino, which is electrically neutral and a fundamental particle, have a nonzero (albeit very small) magnetic moment? How is that even possible? Does...

I'm trying to understand a bit about CP violation and how it relates to neutrino oscillation. I have a book, "Introduction to High Energy Physics" (Donald Perkins) which says that the probability of observing no change in the flavour of a neutrino is equal to that of an antineutrino of the same...

they are in two different generations, but they would behave in the exact same way. maybe we can tell from neutrinos? Thanks!

I'm trying to learn the basic theory of neutrino oscillations at a postgraduate level. I have a few things that are bothering me. 1) All of the papers & textbooks I have looked at start out by just assuming that each neutrino flavour eigenstate is a superposition of the mass eigenstates...

Okay, so, the FTL neutrino result from the OPERA experiment is still being questioned, and that's good. But, assuming they really did travel faster than light, I have a few questions: 1. Didn't we learn that if things travel faster than light then they travel back in time? So if the neutrinos...

Hi, I've just registered in the forum because I have a couple of Physics questions. I'm not a specialist, and furthermore English is not my mother tongue, so please be indulgent with me. As far as i know (please correct if not), only two sources of natural 'extraterrestrial' neutrinos have been...

Hi just a quick question I was curious about. Im not sure if the results from CERN about the faster than light neutrino have been verified, but given that this is true... as I understand it bell's inequality assumes 1. the reality of the external world, independent of us "observers". 2...

If I just know the energy range of it is 10-35 MeV, and they can interact with detector for 10 seconds, how to deduce the upper limit mass of it?

It appears that the faster-than-light neutrino results, announced last September by the OPERA collaboration in Italy, was due to a mistake after all. A bad connection between a GPS unit and a computer may be to blame...

Hello. I wonder - is the CνB energy curve expected to follow the Boltzmann distribution? In the 2 seconds neutrinos were in equilibrium with matter, did they bounce off enough to even out the energy? I'm asking because a back-of-envelope computation gives cosmic neutrino speeds of ~0.09c...

I'm aware a neutrino does not 'interact' with other particles nor have charge. But in the Super-K detector, neutrinos are said to be detected through the 'charged particles they generate when they occasionally interact with other particles.' How exactly does this occur? I mean, what does...

Hello, My first post here, so please be gentle if I make mistakes of any kind... Has anyone else noticed the relation between the mass under the standard model of the three known neutrinos? When plotting the difference of mass between the "generations" on a (natural) logarithmic scale...

The current information in regards to the Neutrino experiment at CERN leads me to two possibilities. 1. The actual speed of light is possibly a bit different than our current value. OR 2. The Neutrino does move faster than c. Is the scientific community leaning one direction or the other? Or...

It is probably a silly question but I just wanted to clear it out... Is the uncertainty principle valid for small particles because we can't find something less energetic/massive to probe the observables ... ? For example if we find a way to probe let say electron firing neutrino at it (it...

I hope you don’t mind me asking this OPERA question here but I think it’s more of a QM question. I just watched NOVA Ghost Particle and it got me thinking. The only problem is that my brain isn’t strong enough to hold all that I’m reading about this experiment. From what I gather, the CERN...

I've been reading about the solar neutrino problem. I heard that if the neutrinos had mass, then they could "oscillate" between all three types. Whatever. I'll buy it. But here are two things I don't get: Why do they need mass to oscillate (is it because having different masses is the...

If FTL was true, shouldn't SETI start searching patterns also in neutrino bursts, and not scan as they do now, only electromagnetic radiation? Wouldn't it be wiser for an intelligent species to cut down transmission time, by sending messages using FTL particles?

where exactly neutrino located in an atom? how many neutrinos are there in a hydrogen atom?

"six sigma" in neutrino article? I was reading this article... http://www.physicstoday.org/resource/1/phtoad/v64/i12/p8_s1 in the first paragraph they say "...notwithstanding the assertion that it is a six-sigma effect". What does this mean? I tried to google, but didn't find that very...

Hello there, I am looking at the decays of Heavy sterile neutrinos in the their mass states to Z bosons. Using the feynman rules, how would I go about calculating the decay amplitude. I have only ever seen cases where the Z boson is a propagator. Would my expression look something like this...

By now, I've listened several times to Brian Greene's talk about the OPERA experiment. And, although I largely agree with him, there's one nagging question I have: Gravitation was, at a time soon following the Big Bang, a repulsive force. The existence of "Dark Energy" suggests the...

Decay of tauon into pion and neutrino... Hello all. I have a question. One of the weak decays of a tauon(energy 20GeV) is to a charged pion(rest mass 139.6Mev/c^2) and a neutrino(take the neutrino to be massless). What condition results in the maximum energy of the pion after the...

what happens if a neutrino hits head on with a proton,neutron or an electron?

Neutrino Oscillation for Dummies If someone has the time to answer these questions, it would be much appreciated. According to Wikipedia http://en.wikipedia.org/wiki/Neutrino_oscillation" is of "interest since observation of the phenomenon implies that the neutrino has a non-zero mass"...

what is the origin of a neutrino? from which part of the atom it comes?

how will a neutrino behave near a block hole? neutrino is having small mass. so it should be sucked into it?

a neutrino moves in a straight line until it hits a particle head on. it is also said that most of the neutrinos pass through the earth!. do u mean to say that total number of all the atomic particles in the diameter of 12000km of the Earth is as good as not there?

i want to know how neutrinos interact with strong beam of laser , if laser beam is going in opp direction along a neutrino beam?

What is a neutrino?

Hello, I just spent some time reading the recent OPERA-CNGS paper on apparently FTL neutrinos (http://arxiv.org/abs/1109.4897) . In this reading, I have some difficulty to clearly see how the arrivals events are processed. I am not even sure I understood properly basic information like...

...shouldn't it: 1. become asymptotic to c as you pump more energy into it? 1a. don't I need to a lot more energy to move it a little closer to c? 1b. can't I compare it with a beam of light to confirm that light is faster? 2. be able to come to rest as you take energy away from it...

this thought was inspired by the recent news about FTL neutrinos. of course i suspect their instruments are broken and that no such thing happened, but regardless, the question stands: it's easy to talk about the rest frame of classical objects where the notion of "trajectory" applies and...

Neutrino discovered to travel FASTER than LIGHT? http://online.wsj.com/article/AP58b5aed0a77c45ddb163d90951b36b35.html I don't know if this is old news, but I do know that the news often gets information wrong is this correct has anyone heard of this? Apparently neutrinos were discovered to...

Edit: Before posting in this thread, we'd like to ask readers to read three things: The https://www.physicsforums.com/showthread.php?t=414380". Don't forget the section on overly speculative posts. The paper http://arxiv.org/abs/1109.4897" The previous posts in this thread And...

Hi, When we talk about neutrino oscillations, the discussion is always about the phase that a particular flavour eigenstate picks up with time. The phase is usually partly geometric and partly dynamic. I have a question about this. How do we measure the phase experimentally? What is the...

If I moved in the rest frame of a solar neutrino would I still measure neutrino oscillations? Thank you for any help!

Is it possible shortly to explain, what is reason that neutrinos oscilate, from one color to others? It can be found some articles, but, is it possible in a few word, maybe in similar language as Feynman, who use basic rules of quantum physics.

It is promised that the quantum coherence will help to improve various measurements. Is it theoretically possible to improve detection of neutrinos with help of quantum coherence?

Hi, When we consider the two neutrino mixing case, we have the matrix that converts between them as given below \begin{pmatrix} |v_{1}> \\ |v_{2}> \end{pmatrix} = \begin{pmatrix} cos\theta & sin\theta \\ -sin\theta & cos\theta\end{pmatrix}\begin{pmatrix} |v_{e}> \\ |v_{\mu}> \end{pmatrix}...

Neutrinos are emitted with corresponding leptons (e, mu ,tau) and that's a conservations law(?) what about when neutrinos oscillate into each other is that a violation of that law? also is there a corresponding oscillation in the other leptons and other particles?? Thanks :wink:

Hi, We know that when we have one flavour of neutrino, it can change into another flavour by neutrino oscillations. However, if we consider a mass eigenstate, then is it true that it can never change into a different mass eigenstate? In other words is a |v_{1}> neutrino forever a |v_{1}>? I...

Hi. I'm a college undergrad (junior year, so basic knowledge of QM but not much else) and I'm reading up on neutrino oscillations. I have a few questions. For neutrinos, which is more fundamental: The mass eigenstates or the flavour eigenstates? In this paper...

Even though the neutrinos are massless and undetectable,how did the physicists established the existence of such particle?

High energy gamma rays in a region of reasonable matter density quickly produce a plethora of lower energy photons by a series of interactions, stopping when you have photons too low in energy to produce positron/electron pairs. My question concerns the likelihood of the titular reaction...

From an entropy argument it is concluded that the CMB neutrino temperature is (4/11)1/3 of the CMB photon temperature. This assumes massless neutrinos. Although neutrino contribution to the present energy density is therefore very small, it was significant must earlier, such as at the time of...