neutrinos

  1. Physics4Eva

    I Neutrino Confusion

    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...
  2. J

    A Why do we write that there are no right-handed neutrinos?

    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 /...
  3. jim mcnamara

    I MiniBooNE results at 6.1 sigma: Potential evidence for sterile neutrinos

    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
  4. K

    I Neutrino mass

    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?
  5. D

    B What particle(s) pass through Earth?

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

    I Neutrino flavour eigenstates and expansion of the universe

    Neutrinos were flavor eigenstates at the time of their decoupling from baryonic matter. Since they were not pure mass eigenstates, how do you take this fact into account if you try to study how they evolved as the universe expanded? Could we determine if the heaviest neutrino could be non...
  7. M

    I Neutrinos interact with photon in "level tree"?

    i found reading the possible interaction of neutrinos with photons to not "level tree", what's the meaning of level tree? and how is that posibble ?
  8. W

    B Coordinated galactic bangs instead of big bang

    The theory of cosmology assumes that the universe has been created from a single point by one big bang event. This theory implies processes which exceed the speed of light. <<Mentor note: This post has been edited to remove some content.>>
  9. V

    A Transforming lepton basis to diagonlise charged lepton mass

    To determine the mass of charged leptons, we rotate such that the matrix of yukawa couplings (which gives the mass matrix after EWSB) is diagonal. We also call this flavour basis for neutrinos, because the flavoured neutrinos couple directly to the correspondong flavoured lepton in weak charged...
  10. C

    A Are neutrinos created by pair production

    Assume just for this question that a neutrino has a mass of 1 ev. That is about the energy of an infrared photon with a wavelength of 1 micron. Is it possible for a visible light photon, or a more energetic photon, to create a neutrino-antineutrino pair?
  11. Seanra

    I My lecturer says "Special relativity is absolutely wrong"

    Hi guys In an assignment I wrote for university I was penalised for claiming that FTL neutrinos would violate special relativity. Below is the relevant part of my assignment and the response from my lecturer. Could somebody please explain what he could mean by that because as far as I can...
  12. S

    I How do neutrinos conserve angular momentum?

    I'm learning about beta decay and as I understand in beta decay we get: neutron → proton + electron And since all these have spin 1/2 we have that the conservation of angular momentum is not conserved. The neutrino with spin 1/2 is proposed to also exist in the process to solve this so that...
  13. D

    Neutrino Decoupling Function

    Background: Neutrinos decouple at around 10^10 K (or 1 MeV). This is normally shown as the interaction rate (between neutrinos and electrons) over the hubble constant: Gamma/H = (T/10^10 K)^3 My problem: I have a function which is dependent on the neutrino-electron interaction. But it does...
  14. T

    How would neutrinos affect fusion?

    How would fusion processes be affected, by a background bath / sea of neutrinos ? Would the constant interactions between fusion products, and neutrinos, constantly break apart the fusion products, and so tend to "undo" the fusion?
  15. TerranIV

    Could Dark Matter be composed of neutrons?

    I was thinking about the properties of dark matter - how it doesn't seem to interact with any of the forces of the universe except gravity and I was thinking about how neutrinos also don't have any charge and they don't interact with any other forces except the weak force and gravity. I thought...
  16. P_Ravensorow

    Percentage of Matter, Dark Matter and Baryonic Matter

    How do we know that out of 100 percent, 4.96% is Matter, 0.42% is Neutrinos, approx 25% Dark matter and rest 70% is dark energy. How do we know about these percentages if we don't know how large the universe is? Or are these calculations based on the spaces of the VISIBLE universe? Are Dark...
  17. K

    Schools Grad Schools for Neutrino Experiment

    Hi everyone. I think for grad school I want to do work on neutrinos. Anyone know of any good and up and coming schools with good faculty working on these experiments? My application should be good, but not great with great grades/research but very average GRE and PGRE scores.
  18. lalo_u

    Right handed neutrino in SM

    I am reading Mohapatra's book: "Massive Neutrinos in Physics and Astrophysics". At the beginning of chapter 7, it is sought expressions where the right neutrino was considered in the Electroweak Standard Model. Everything was fine until I found the expression...
  19. lalo_u

    Right handed neutrino identity

    I am reading Mohapatra's book: "Massive Neutrinos in Physics and Astrophysics". At the beginning of chapter 7, it is sought expressions where the right neutrino was considered in the Electroweak Standard Model. Everything was fine until I found the expression...
  20. R

    Neutrino Communication Problem

    Homework Statement I need some help understanding the following problem: A distant, advanced civilization wishes to make contact with us using neutrinos rather than photons as the transmitting medium to avoid problems of obscuration along the line of sight. Suppose they use an \bar{\nu_e}...
  21. O

    Neutrinos-Antineutrinos in the universe

    Hello everybody, I am a first year physics student and I have a question about neutrinos and antineutrinos. In a beta minus decay we will get an antineutrino, so I assume that Earth 'produces' more antineutrinos. Does it? However from a beta plus we get neutrinos and positrons. So does...
  22. L

    Handedness of neutrinos and antineutrinos

    Could anybody explain why neutrinos have only ever been observed to be left-handed and antineutrinos right-handed? If neutrinos travel slower than light and have mass (albeit very small), as shown by neutrino oscillation experiments, why can neutrinos not change their handedness?
  23. E

    High energy neutrino telescopes

    Hello, I am opening this thread so as to discuss if possible what you believe is the science case of building a neutrino telescope. Being a fanatic in the field , I would like to hear opinions from whoever wants to say about whether it is important to build such a detector and why. Thank you!
  24. C

    What happens to the electron neutrino post beta+ decay?

    In β+ decay a proton releases a positron and an electron neutrino causing the proton to change into a neutron to help balance the nucleus. I am studying advanced PET imaging and trying find a better understanding of the positrons other half. Does it just go on being a normal electron.
  25. marcus

    Weinberg's dark matter idea re fractional cosmic neutrinos

    Weinberg's dark matter idea re "fractional cosmic neutrinos" http://arxiv.org/pdf/1305.1971v1.pdf http://arxiv.org/abs/1305.1971 Goldstone Bosons as Fractional Cosmic Neutrinos Steven Weinberg (Submitted on 8 May 2013) It is suggested that Goldstone bosons may be masquerading as fractional...
  26. W

    Neutrino polarization

    I was reading in my QM book that neutrinos are "essentially left handedly polarized." (Townsend on Page 119) If neutrinos can be polarized, what is oscillating? Do other particles with mass exhibit polarization?
  27. Rlam90

    Neutrinos to probe nuclear structure?

    Do you think it would be possible to use a beam of neutrinos to probe the structure of atomic nuclei? Since they do not interact electronically, they would be useful to study the structure of both neutrons and protons, either through gravitational deflection or weak interactions. Could this...
  28. J

    Estimating Neutrino Flux Density

    1. Problem "Estimate the flux of neutrinos passing through your body per second if the present energy density of neutrinos from the Big Bang is 0.2 MeV/m3. Assume that you are a standard size covering 0.01 m2". Homework Equations nv = Uv(T) / <Ev> The Attempt at a Solution I've assumed that...
  29. xortdsc

    Interaction between Neutrons/Neutrinos

    Hello, I was wondering if there is any evidence on how (free/not within nucleus) neutron/neutron interactions work. I know there is QCD which states they attract (but maybe only in a nucleus?), but that's theory - has this been experimentally proven at all ? I'm only interested in the free...
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