Neutrino Definition and 379 Threads

I understand that neutrinos are emitted when supernova explode. I presume that there are quite accurate models that predict the energies of those neutrinos at the time of emission. Has the phenomenon of redshift been observed when those neutrinos are subsequently detected?

I understand the basics of neutrino oscillation from the starting point of each neutrino flavour state being a superposition of mass states, or vice versa. However, the introductory texts I've seen never seem to explain what motivated such an idea. What made Pontecorvo think this?

Hello everyone, Are neutrino flavors conserved in interactions other than neutral particle oscillations?

They make fluorine, according to a large new study. Link: ScienceNOW

Homework Statement...

"Other experiments to test whether the neutrino is, weirdly, its own antiparticle may be feasible only if the hierarchy is inverted." Why? http://news.sciencemag.org/physics/2015/08/u-s-neutrino-experiments-first-result-tantalizes?utm_campaign=email-news-latest&utm_src=email

basic question- neutrinos pass through matter because they are only subject to the weak interaction whereas photons interact with matter because they are subject to EM? Does the small mass of the neutrino contribute to this - if there was a neutrino with the mass of a proton how differently...

Energy of beta ray and neutrino is equal Q=M(mass) of nucleous before-M of nucleous after,so it about 1Mev.But the mass of W boson is 80 MeV,so the least energy of electron and neutrino must be 80 MeV. Why there is the difference?Why does it seem that energy were not conservation?

mfb submitted a new PF Insights post Neutrino Masses and Speed Continue reading the Original PF Insights Post.

Neutrinos are always left handed* and so, if you set up a coordinate system with the z-axis pointing in the direction of a neutrino's momentum, any measurement of its spin's z-component will always yield ##-\hbar/2##. What if you measured the spin of the neutrino along the x or y axes? Or is...

Hi mfb: The following messages were in the now closed thread "Neutrinos-Antineutrinos in the universe". Bill_K said (msg #2): Most of the neutrinos we detect are solar neutrinos coming from p + P → d + e+ + ν. I said (msg #5): Is the "P" here a typo where "p" was intended? If not, what does...

In another thread a point was raised that current theory (or perhaps experimental results) establishes a definite (or appromimate) relationship between the average and the variance of the rest masses for the three flavors of neutrinos. I have tried to educated myself from material I can find on...

Homework Statement Neutrinos with energy of about ##1 GeV## are measured in an underground detector and compared with simulations of neutrinos produced in the atmosphere. Measured flux of upward going muon neutrinos ##(\nu_\mu + \bar \nu_\mu)## is half compared to simulations while measured...

Hi Since a few days I've been confused about the seesaw mass matrix explaining neutrino masses. It is the following matrix: \begin{pmatrix} 0 & m\\ m & M \\ \end{pmatrix}. As can easily be checked it has two eigenvalues which are given by M and -m^2/M in the limit M>>m (the limit doesn't...

Hello, I need to research online about the difference between neutral meson and neutrino oscillations. However I've found this difficult. I haven't found anywhere any comments on the differences between the two. The only thing which comes to mind is that the mesons can interact in their mass...

Dear PF Forum, I once read in several links just a couple of days ago, that the number of neutrinos exceeds the number of baryon in the universe by several orders of magnitude. 1. Is that true, that neutrinos are much more abundant than atoms? 2. Do neutrinos have mass? Not that they are...

Hi, I have some problem in deriving \Delta m_M^2 as given in eq.35 here: http://www.slac.stanford.edu/econf/C040802/papers/L004.PDF When I tried to derive the eigenvalues of H_M (eq.33) I got: m^2 = (\cos 2 \theta -x)^2 + \sin^2 2 \theta which is only one eigenvalue. Any help? In...

We know that there are 3 generations of neutrinos, namely the electron neutrino, muon neutrino and the tau neutrino. The masses are all very small compared to their respective leptons. What evidence is there that these neutrinos of different generations are distinct?

Hello. Probably a stupid question, but hey why not. Since Neutrino's do not interact with electromagnetic fields, but cosmic rays and other particles (that would overwhelm a neutrino signal if observed in an environment not at least partially shielded from their signals as at SNO etc) DO...

I have seen that people write the PMNS matrix as a multiplication of the form: \text{PMNS}= A \cdot S_{ub} \cdot S_{ol} \cdot M \text{PMNS}= \begin{pmatrix} 1 & 0 & 0 \\ 0 & c_{23} & s_{23} \\ 0 & -s_{23} & c_{23} \end{pmatrix} \cdot \begin{pmatrix} c_{13} & 0 & s_{13} e^{-i \delta} \\ 0 & 1 &...

Hi Why are there three types of neutrinos? Why isn't there just one neutrino just like there is only one electron? (I mean electron doesn't have different flavours to it, same with tau and muon.) My textbook touches on this very breifly and confuses me with "if there were only one type of...

Could someone provide the e-books about neutrino physics? thanks.

What would be the signature in a neutrino detector of these interactions? \nu_l q \rightarrow q^\prime X and \bar{\nu}_l e \rightarrow \bar{\nu}_l l^- with q a nucleon's quark and l^- a lepton? In general I would say that the signal would be that of the resulting lepton and maybe hadron jet...

As a neutrino is capable of movement at a rate greater than that of light, and as such flows backwards through time relative to our own perspective, then why do we attempt to understand it through causality, rather than effect and cause as opposed to cause and effect? Why should we expect that a...

Hi there, In Reference as hep-ph/0306037v2, we see the effective Hamiltonian of ## B \to l \nu ## equ. 1, which has the SM and the NP parts. In equ. 4, it seems that ## m_l ## comes from ## P^\mu_B ## equ. 3. The question that how ## P^\mu_B ## yields ## m_l ## ? Where ## P^\mu_B = ( E_B, 0...

A left handed neutrino (chirality) can be seen with a right helicity due to a lorentz boost. Can this neutrino interact ? Yes because it is still left-handed chirality ?

I am trying to explain why why the survival probability for solar neutrinos is different for different neutrino solar lines, and what causes this difference.

Homework Statement Considering just the electron and the muon neutrino, The Free hamiltonian is written in this basis as: H = 1/2 (E + Δ Cos[θ]) |Ve><Ve| + 1/2 Δ Sin[θ] |Vu><Ve| + 1/2 Δ Sin[θ]|Ve><Vu| + 1/2 (E - Δ Cos[θ]) |Vu><Vu| Since H is not diagonal in this basis, they will exhibit...

A neutrino converts a chlorine-37 atom into one of argon-37 A neutrino is also able to react with an atom of gallium-71, converting it into an atom of germanium-71 It looks to me as if the neutrino was changing into a proton in both cases as argon has 1 more proton than chlorine and likewise...

Hello All, I am pretty sure that when a nucleus decays via e.c. and goes to the ground state all of the excess energy is released with the emission of the neutrino but was wondering if anyone could confirm/give a reference for this. Thanks!

Suppose you have a source of electron antineutrinos, and you arrange your apparatus so that a billion billion billion of them collide directly with a black hole. In principle, you could measure the change in momentum and energy from that occurrence. Suppose you did that the next day. According...

Consider this report: http://www.physics-astronomy.com/2015/01/quantum-teleportation-of-subatomic.html "Then, the researchers shot a third particle of light at the photon traveling down the cable. When the two collided, they obliterated each other. Though both photons vanished, the quantum...

How massive would the neutrinos have to be so that relic neutrino from the big bang would account for all dark matter?

What is the current upper limit on the mass of the most massive neutrino? How is that limit measured? Thanks.

I just came across this paper arguing that the electron neutrino may have negative mass squared: http://arxiv.org/abs/1408.2804 It says it has been accepted for publication. I'm wondering if anyone has seen it and can comment on the paper's arguments.

Hello I'm working through the see-saw mechanism. This is currently from the one-generation section. (I haven't got to the three generation workings yet... although I'm guessing I'll come across something very similar in the three generation model) Could someone please tell me if it is correct...

I've seen explanations that when a neutrino with a W+ Boson comes near a neutron, it affects one of the bottom quarks and changes it to a up quark which effectively turns the neutron into a proton. The neutrino then turns into an electron. Source: (2:20 onwards) I've seen other explanations...

Hello I'm trying to work through a see-saw model derivation and I've become a bit stuck. I've tried lots of sources but the difference in conventions doesn't fill me with confidence when combining these sources. I need to get from ## \overline{ \nu_L^c } \nu_R^c + h.c ## to ## \overline{...

Hello Why are neutrino oscillations insensitive to Majorana phases? I'm guessing it has something to do with them being factored out the PMNS matrix using a diagonal matrix ... i.e. U_PMNS = U Diag (a1, a2, 1) Is there a point in the oscillation calculation where they always cancel due to a...

How would i go about working out the percentage of energy carried away by neutrinos in a PPI chain?

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...

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...

When the Z boson is around can a neutrino interact with a particle other than an electron? And how does the neutrino find the electron if the neutrino is neutral and does not interact electromagnetically?

What's the difference between a neutrino and a Muon? Will a neutrino induce fusion the same as a muon? Does muon induced fusion take place in the sun? Any help is greatly appreciated.

[SIZE="4"]Definition/Summary There are three masses of neutrino (they are unknown, but the differences of their squares is known approximately). There are three flavours of neutrino: electron- muon- and tau-, and a neutrino when it is created must be one of those three flavours. Each...

A charged lepton can absorb a W+ boson and be converted into a neutrino, and visa versa. The neutrino has such small rest mass, how can it produce these large particles/be produced by them?

Hi all! I am not sure how to prove mathematically that the expression for the probability that a neutrino originally of flavor α will later be observed as having flavor β P_{α \rightarrow β}=\left|<\nu_{\beta}|\nu_{\alpha}(t)>\right|^2=\left|\sum_{i}U_{β i}^*U_{α i}e^{-iE_it}\right|^2 (1) can...

I'm stucked in a passage of Particle Physics (Martin B., Shaw G.) in page 41 regarding neutrino oscillations. Having defined E_i and E_j as the energies of the eigenstates \nu_i and \nu_j, we have: E_i - E_j = \sqrt{m^2_i - p^2} - \sqrt{m^2_j - p^2} \approx \frac{m^2_i - m^2_j}{2p} It...

Greetings. I thought about how/ why light propagates slower trough matter than vacuum. Generally it is excepted that it happens because photons are absorbed and then emitted by the atoms and it kinda makes sense. But I see other possibilities. I propose and experiment: How about shining...

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\!\!\!/ +...