A neutrino ( or ) (denoted by the Greek letter ν) is a fermion (an elementary particle with spin of 1/2) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. The rest mass of the neutrino is much smaller than that of the other known elementary particles excluding massless particles. The weak force has a very short range, the gravitational interaction is extremely weak, and neutrinos do not participate in the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded and undetected.Weak interactions create neutrinos in one of three leptonic flavors: electron neutrinos (νe), muon neutrinos (νμ), or tau neutrinos (ντ), in association with the corresponding charged lepton. Although neutrinos were long believed to be massless, it is now known that there are three discrete neutrino masses with different tiny values, but they do not correspond uniquely to the three flavors. A neutrino created with a specific flavor has an associated specific quantum superposition of all three mass states. As a result, neutrinos oscillate between different flavors in flight. For example, an electron neutrino produced in a beta decay reaction may interact in a distant detector as a muon or tau neutrino. Although only differences between squares of the three mass values are known as of 2019, cosmological observations imply that the sum of the three masses (< 2.14 × 10−37 kg) must be less than one millionth that of the electron mass (9.11 × 10−31 kg).For each neutrino, there also exists a corresponding antiparticle, called an antineutrino, which also has spin of 1/2 and no electric charge. Antineutrinos are distinguished from the neutrinos by having opposite signs of lepton number and right-handed instead of left-handed chirality. To conserve total lepton number (in nuclear beta decay), electron neutrinos only appear together with positrons (anti-electrons) or electron-antineutrinos, whereas electron antineutrinos only appear with electrons or electron neutrinos.Neutrinos are created by various radioactive decays; the following list is not exhaustive, but includes some of those processes:
beta decay of atomic nuclei or hadrons,
natural nuclear reactions such as those that take place in the core of a star
artificial nuclear reactions in nuclear reactors, nuclear bombs, or particle accelerators
during a supernova
during the spin-down of a neutron star
when cosmic rays or accelerated particle beams strike atoms.The majority of neutrinos which are detected about the Earth are from nuclear reactions inside the Sun. At the surface of the Earth, the flux is about 65 billion (6.5×1010) solar neutrinos, per second per square centimeter. Neutrinos can be used for tomography of the interior of the earth.Research is intense in the hunt to elucidate the essential nature of neutrinos, with aspirations of finding:
the three neutrino mass values
the degree of CP violation in the leptonic sector (which may lead to leptogenesis)
evidence of physics which might break the Standard Model of particle physics, such as neutrinoless double beta decay, which would be evidence for violation of lepton number conservation.
Supernova Shelton 1987A, located about 170 000 ly from the Earth, is estimated to have emitted a burst of neutrinos carrying energy ~1046 J. Suppose the average neutrino energy was 6 MeV and your body presented cross-sectional area 5 000 cm^2. To an order of magnitude, how many of these...
Those faster than light neutrinos were moving through a location of high gravity (inside the earth). In such locations space is contracted more than in empty space. Therefore getting from A to Z is a contracted distance. Question: could neutrinos move through contracted space at a greater...
This thread got me looking at Neutrinos for the very first time. They are the most recently discovered fundermental particles, the Tau Neutrino was first observed only 11 years ago in 2000.
The neutrino was first postulated in 1930 by Wolfgang Pauli to preserve the conservation of energy...
At the last scattering surface (LSS), the energy density of neutrinos is argued to be ~0.68 of the energy density of blackbody photons, based on a thermodynamic equilibrium argument. This is also required to obtain the correct total energy density for stable expansion. At that time, the average...
Hi everyone, this has been bothering me for a while and even though I've done some light reading on this topic I am struggling to understand it.
I know that theory states that we do not see left handed antineutrinos or right handed neutrinos and this is where cp violations comes from. But...
Cern has reported they have measured neutrinos going faster than the speed of light. Did they send a light beam as a test case to see any variance in c of the light beam?
Also, were two clocks involved in the measurement? One in Switzerland and one in Italy? If so, wouldn’t it be...
The poster attached is about standard model.As you can see ,The neutrinos are categorized as lightest neutrino,middle neutrino and the heviest neutrino.In a part about neutrinos,It is explained that the electron neutrino,muon neutrino and tau neutrino are different mixtures of these three...
I posted this question on two philosophy sites, but so far I have gotten no meaningful responses, predictably so because I'll admit this is a rather far-our idea. But wherever laws deemed absolute are broken, trying to deduce the explanation from the known and understood is not going to work...
Is there any evidence for quantum fermi-dirac distributions among neutrinos, besides the obvious fact about their spin? I was wondering how Pauli exclusion principle would work with a neutrino 'gas', and what kind of quantum numbers they could have.
It has been expected that if we ever did...
I know there's a difference between how they're detected. (Cherenkov radiation cone size) They have different "flavors." (I'm not sure what that means.) There's a difference in their simbol. (Ve, Vu, Vt) And they have different masses. But that's all I know. There must be something more to the...
What is a move? (with these superfast neutrinos in mind...)
When you go to a big restaurant, there are at any given time probably a certain amount of waitresses. It might be, one of them brings a soup, another a coffe and the third the bill.
But they all represent the other reality, the other...
Hello, I was wondering if there was any experimental or observational evidence for neutrinos being affected by gravity. Be it through detected lensing or other means. All I could find were some papers on lensing none of which seemed to have actual results out of the error margin.
PRELUDE:
We consider two points A and X . A light ray flashes across an infinitesimally small spatial interval dL at X.
Local time interval(physical) measured by observer at X:Sqrt[g(X:tt)]dt
Time interval(physical) measured by observer at A = Sqrt[g(A:tt)]dt Local speed of light at...
I believe there needs to be an intelligent discussion somewhere about the possibility that theories with time loops can be rendered consistent by nondeterministic (probabilistic) physics, and specifically about the possibility that genuinely spacelike neutrino effects - which, let us recall...
What is the ratio of energy contained in photons vs energy contained in neutrions in the present universe? Also, how is that ratio changing with time? Thanks.
I have some questions regarding the recent neutrino´s theories:
1. Neutrinos have or don't have mass? I have heard both postures.
2. I have read that reason for neutrinos go through matter (like in the OPERA experiment from CERN to Grand Sasso) is because they don't have mass. Photons also...
I don't think anyone can explain it, but does anyone know what is up with this news about neurtinos going faster than the spead of light? I can feal all of physics crumbling around me whenever I think about it!
I have been wondering why photons can't go through matter and electromagnetic fields mostly unaffected while neutrinos can. Neither of them have an electric charge as a particle, and the basic description I see about neutrinos is always that "they are unaffected because they have zero electric...
Recent news about neutrinos slightly breaking the speed of light. Wondering if it were possible that an unknown tachyon particle existing 'momentarily' therby beating the speed of light, then becoming a neutrino as it 'collapses', becoming a neturino, could explain the phenomena? Yeah I know no...
I feel like this is one of those things where they say "oh my god this will change physics forever" but it ends up being being incorrect. Either way it is odd that they would measure faster then light speed at all, I'll give them that. But 60 nanoseconds? Not quite enough to make me convinced...
Hi , It is experimentally shown that neutrinos can travel faster than light http://www.nature.com/news/2011/110922/full/news.2011.554.html
What are the implications of that discovery ?
Note: NOT finally confirmed yet!
Still, IF true it’s just amazing and the biggest discovery in over 100 years!
OPERA experiment reports anomaly in flight time of neutrinos from CERN to Gran Sasso
http://press.web.cern.ch/press/PressReleases/Releases2011/PR19.11E.html
Measurement of the...
Hello.
I just read this http://www.haaretz.com/news/international/have-cern-scientists-managed-to-exceed-the-speed-of-light-1.386126" which says that scientists in CERN recorded neutrino particles traveling faster than the speed of light.
Now, I know how "scientifically literate" the media is...
I don't know anything about chemistry or physics, so this might be a stupid question. when neutrinos collide with let's say the nucleus of an atom, how much energy would be transferred from the neutrino?
Homework Statement
Neutrinos are created in states of one of two possible flavors, f_1 or f_2. Each flavor state can be expressed as a linear combination of mass eigenstates with masses m_1 and m_2
|f_1\rangle = |m_1\rangle a_{11}+|m_2\rangle a_{21}
|f_2\rangle = |m_1\rangle a_{12} +...
Homework Statement
Neutrinos are massless spin-1/2 particles (ignore their tiny finite masses).
There are 6 types of neutrinos (3 flavours of neutrinos and 3 of anti-neutrinos),
and each has just one possible polarization state. In the early universe neutrinos
and antineutrinos were in...
As I understand, the answer will have to come from neutrino-less double beta decay experiments. When will these experiments reach the required sensitivity and gather enough data, to provide us with a definite answer about the nature of neutrinos?
Homework Statement
I'm asked to draw a Feynman diagram for two neutrinos scattering from each other.
Homework Equations
None
The Attempt at a Solution
I don't really get the question so I don't know what I'm actually supposed to put in the diagram. Am I supposed to draw a diagram...
Given that a photon or neutrino creates a gravitational effect, and given that the CMB, microwave photons emitted 13.8 billion years ago are still around in the universe, then it would follow that ALL photons or neutrinos that have not since been captured should also still be present in the...
Hello, i'd really need some help with the following questions.
1) Neutral Pion
It's quark content is written as: \pi^0=(u\overline{u}-d\overline{d})/\sqrt{2}
But the u-quark have a (quite) different mass than the d-quarks. This means that the neutral pion is a superposition of states of...
Do anyone know why in some article or books, they write the neutrino without distinguish the type among them.
e.g.
\mu\rightarrow e+\nu+\bar{\nu}
does it have speacial meaning to write like this?
Homework Statement
Neutrinos very rarely interact with anything and thus are very hard to detect. About 10^14 neutrinos from the sun pass through your body every second, even at midnight (the neutrinos easily go through the earth), but this is of no concern since only one a day interacts...
I am having real problems fitting nuetrinos into my mental models of the world,when i think of strong,electromagnetic and gravitational interactions i find it much easier to work with because there's always something tangible i can relate it to,fermions,light or falling for example,but when i...
Hey, I would like to ask you: I need have Standard Model with right-handed neutrinos. This is the simplest extension of SM which contains the Dirac and Majorana neutrinos.
PR (right projection operator) coefficients should be nonzero. Is that enough? But what is their value? In the SM for the...
Pulse of neutrinos, E>>m, hits plasma-->charge seperation?
When a large pulse of neutrinos, each with an energy much greater than the electron rest mass energy, hits some plasma does this give rise to charge separation for the plasma? Could one make a simple argument why this is true or false...
Reading from The Astrophysics Spectator:
http://www.astrophysicsspectator.com/topics/supernovae/SupernovaeCoreCollapse.html
"When a stellar core collapses, its high density spurs the creation of thermal neutrinos through a variety of processes. The core itself is not transparent to...
I was reading an article about neutrinos in a Science Illustrated magazine about a month ago. And in this article it stated that when a neutrino collides with another particle, you know the direction from which the neutrino came from and the flavor of it.
A neutrino is a non-charged, non-zero...
Hi, I'm trying to find out the total number of solar neutrinos that interact with the human body per second or per lifetime. I know we are exposed to many, most which pass straight through us, but I'm interested to know how neutrinos interact with matter.
Thanks.
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...