Neutrino Definition and 390 Threads

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...

Hey...i'm studying the reaction neutrino+antineutrino -> W(+) + W(-) but i don't understand which are the relevant f. diagrams at first order (semiclassic approximation). Does anyone know which are? thank you

Like the question says, would a neutrino be stopped by the very high density matter in a neutron star? IH

If I'm not mistaken, the 3 flavours of neutrino are supposed to have different masses, right? Why then, if you had, say, an electron neutrino traveling along with a certain value of (kinetic + mass) energy, and then it oscillates into a muon neutrino with a different mass, could that be allowed...

I am working on a neutrion based thruster to be used in atmosphere, somewhat based on the A Cavity-Type negative ion source. Actually it is the next generation using neutrinos as the energy source. I saw your post and thought you might be someone to bounce some of the ideas off. Our original...

I posted this question on Yahoo Answers and got no responses than I found this site and figured it would be more reliable... I am no physicist but I have been reading up on particle physics for fun lately and have come across something i do not understand. We know that the mass of a...

During the trip from their supernova, they passed through expanding space together. The photon says to the neutrino, "I think I've been redshifted." What happened to the neutrino?

My interests are in astrophysics, so please forgive my ignorance of particle physics. I've just read Frank Close's book, "Neutrino"---excellent read, I'd recommend it---in which he points out that Ray Davis' first experiments to detect neutrinos from nuclear reactors (with no detections)...

Hello! I've got this question (attached as jpg) about the neutrino fluxes at earth. I don't know how to use the branching ratios in order to solve it. (Do I really need these ratios?) Thanks. Ted.

I understand that no such discoveries have been made. But there must be some astrophysics models which predict the abundance of neutrino sources. If there are such models, what are the odds that IceCube spot a neutrino source, after several years of operation?

Sorry if this qs been asked before, i couldn't find one similar.

So every particle with some mass, even if the mass is very, very close to zero has a rest frame. A neutrino, say, could sit right next to me. But a photon, a massless particle, of course, can't, it has to zip by with light velocity. But when I would reduce the mass of a particle slowly...

Homework Statement A supernova 1.54\times10^21 m away sends out neutrinos, and a detector on Earth detects two, ten seconds apart. The first one (A) that comes has a kinetic energy of 30 MeV, the second (B) has a kinetic energy of 10 MeV. Using this, I'm supposed to come up with an upper...

My understanding is that Fermi has results that show the mixing angle for neutrinos is not the same as the mixing angle for anti-neutrinos. Is there a theory that explains this?

spin and mass of neutrino,

Do you know a particle smaller than an electron neutrino? An electron neutrino is far by the smallest particle I know! Do you know something smaller than that?

Homework Statement If the Superkamiokande neutrino detector could accurately determine the direction of detected neutrinos, what would the angular diameter, in arcminutes, be of the neutrino emission as seen from Earth. Assume all the neutrinos are ^{8}B neutrinos with energies <14.02MeV...

A beam of negative pions enters a bubble chamber and triggers the following reaction and successive decays all take place within the bubble chamber: \pi- + p \rightarrow \Lambda0 + K0 \Lambda0 \rightarrow \pi + p K0 \rightarrow \pi+ + \mu + \bar{\nu} \rightarrow e- + \nu + \bar{\nu}...

when beta decay is observed it is noticed that some of the energy and some of the momentum is missing. it is thought that this missing energy and momentum is carried away by a neutrino. the neutrino mass is still unknown. if you know how much momentum (mv) is missing and you know how much...

I am an electical engineer who just likes to read about science. I have recently read a number of articles about neutrino research being done in old mines deep below the surface of the earth. Everything I have read about neutrinos indicates that they go through everything including the earth...

I'm interested in the history of the discovery of the neutrino suggested in 1930 by Pauli and I read that the first clue came from the fact that beta decay energy from electrons had a continuous rather than discrete spectrum and this seemed to contradict the energy conservation law. I would...

Im a little confused about how to calculate threshold energies. The threshold energy is when the energy is as low as it can possibly be and still do what it has to do, yes? So when a neutrino is detected its speed is refracted by water and so it slows down. If at the threshold the neutrino speed...

I'm wondering how to calculate the neutrino diffusion time-scale from a neutron star---just to an order of magnitude or so accuracy. Based on a 10km, 1.4 solar-mass star, and a cross section \sigma_{\mu n} \approx 10^{-42} cm^2; I found the mean-free path to be l \approx 10^{14}cm. Then using...

Why neutrino may have magnetic moment? Even if it is massive... it is not composite and it is electrical neutral...

While neutrinos have no electric charge they have magnetic moment and will interact with magnetic field causing precession of its spin.http://prl.aps.org/abstract/PRL/v45/i12/p963_1" So if neutrinos can interact with virtual photons what makes it impossible to interact with real photons...

can the neutrino mass eigenstate couple to the group of SU(2) doublet?if we intentionally not impose any flavor symmetry on it. \left(\begin{array}{c}\nu_{1}\\e\end{array}\right)

Hi, I'm Chen. Recently I was trying to study the neutrino interaction with electron. Question: can Pythia generate the event of ( e , neutrino ->...) ? if so, please help me for input program. thanks Chen

can anybody explain what is the difference between neutrino flavour state and neutrino mass eigenstate?getting confuse on it again...

how would we know that the muon is decay into electron antineutrino and muon neutrino to give the muon lifetime of about 2microsecond?

Recently, the MINOS detector has shown results that call into question the symmetrical properties of anti-neutrinos with respect to neutrinos: http://arstechnica.com/science/news/2010/06/antineutrino-masses-throw-physics-a-curve.ars More strange results came from MiniBooNE...

Neutrino vs Photon Propulsion So neutrinos, once thought to be completely massless and travel at the speed of light, have recently been deduced to have mass because of their ability to undergo flavor change. It's not known however exactly how much mass the neutrino has. So what then would...

The May 2010 issue of Scientific American had an article titled http://www.scientificamerican.com/article.cfm?id=through-neutrino-eyes". I enjoyed the article and read it several times. It made me wonder though - how much energy in the form of neutrinos is passing through any given space...

Hm, I wonder since neutrino's have no electric charge or color charge, but do have mass, is it possible for two neutrinos to come so close together that they collapse on themselves? Although the gravitational field between just two neutrinos is extremely small, it should still be possible right...

Hello! Have a question: Imagine a world described by the Standard Model, supplemented with three right handed neutrinos, and massless charged leptons, would neutrinos oscillate in such a world? Thank you!

Homework Statement Is the following process a valid interaction? \nu_\mu \bar{\nu}_e \rightarrow e^+ \mu Homework Equations none The Attempt at a Solution I'm not sure whether lepton number must be conserved at each vertex, or just for the overall process. I can draw a Feynman diagram...

I've been reading up on neutrino oscillations and I have come across this issue. I know that oscillations are dependent on the mass squared differences of the mass eigenstates, which is why determining things like the absolute masses of the eigenstates and the hierarchy of the eigenstates is...

Hello, does anybody know how to compare (at tree level) the two reactions e^- + e^+ \to \gamma^\ast \to e^- + e^+ and e^- + e^+ \to Z^\ast \to \nu + \bar{\nu} \;\;\; \text{and} \;\;\; e^- + e^+ \to W^\ast \to \nu_e + \bar{\nu}_e The first process is the so-called Bhabha...

Homework Statement Every reaction in the sun has the energy equivalent to 0.03 mp, and generates 2 neutrinos per reaction. Calculate the number of neutrinos per second, and calculate the neutrino flux at Earth. Astronomy generally uses the CGS (centimeter gram second) system, so just be...

Dear fellow Physicists, I am writing to ask what the significance of the term (L/E) in neutrino oscillation is? From my initial understanding it determines the oscillation mode, so if you have an experiment of a baseline of 300km, you can adjust the neutrino beam energy to suit the particular...

I understand that K_l = \frac{d\bar{s} + s\bar{d}}{\sqrt{2}} K_s = \frac{d\bar{s} - s\bar{d}}{\sqrt{2}} This happens because K_0 is oscillating into its own antiparticle. My question is, why the same is not applicable to the neutrinos? They do oscillate. So instead of ‘pure’ e, mu, tau...

when an electron neutrino is produced in the sun, it have the total energy of E. the total energy E have the relation with mass and momentum as E2=p2+m2. during the journey of its propagation from sun to earth, the electron neutrino change their flavor to muon neutrino which have mass m'...

In books I find that the Majorana mass term for the neutrinos is given by m_L \nu_L^T C^\dagger \nu where C is Dirac Conjugation operator. How does C look like if I write \nu_L as in terms of its two components \left(\begin{array} (\nu_{L1} \\ \nu_{L2} \end{array} \right)? Is C=...

One of the unstable isotopes of caesium undergoes beta decay, as a result of which it turns into an isotope of Barium, with the simultaneous emission of an electron and a neutrino. The Caesium isotope is 1.18 Mev/c^2 more massive than the Barium isotope. Assuming that the initial and...

Homework Statement I doubt that my problem is supposed to be in the Advanced Physics forum, but the subject is advanced. Okay, my problem is pretty stupid. The assignment is deriving a probability using some approximations and such, for 2-neutrino oscillation. I can do the entire calculation...

When you attempt to measure the motion a neutrino or a photon, one of the two subatomic particles being a massless particle and the other particle being a ghost particle, how would either of the two particles interact in a quantum state if both particles don't posses an inherent mass? I know...

I have some well ordered feyman diagrams which have an incoming neutrino interacting at a vertex with a w boson and emitting an electron. since a neutrino can pass through some 18 light years of led without interacting, I'm wandering how a single neutrino interacts at this vertex?