Main Difference – Neurons vs. Neutrinos
Neutrons and neutrinos are two different types of particles. The main difference between neutrons and neutrinos is that neutrons are made of quarks, whereas neutrinos are a type of fundamental particles that are not made of any other particles.
What is a Neutron
By the early 1930s, physicists had already discovered protons and electrons. They had known that protons reside inside the nuclei of atoms. However, they realized that the mass of the nucleus didn’t tally with how much charge the nucleus had. In order to explain this discrepancy, most scientists at the time believed that some of the protons in the nucleus are paired with “nuclear electrons”. They expected these electrons to be inside the nucleus. This way, these “paired” protons would still contribute to the mass of the nucleus, but they would not be able to contribute to the charge since their positive charge is effectively “cancelled out” by the negative charges of the electrons. During beta minus radiation, electrons appear to come out of the nucleus, and this observation also seemed to support the hypothesis that there are electrons inside the nucleus of an atom.
However, there was an issue with this explanation: the electrons that were coming out of the nucleus did not have as much energy as the model had predicted. Meanwhile, in an experiment where some light nuclei were bombarded with alpha particles, it was discovered that the nucleus radiated some particles that showed better penetration abilities than protons. James Chadwick discovered that these radiated particles were neutral and decided to call them “neutrons”.
Sir James Chadwick
Today, we know that neutrons make up the nucleus of the atom, along with protons. They are slightly heavier than protons, and they carry no charge. We also know that they themselves are made of quarks, three valence quarks (an “up” quark and two “down” quarks) and a “sea” of other quarks that continually pop in and out of existence. Because they are made of quarks, in the Standard Model of particle physics, they are classified as “hadrons”.
What is a Neutrino
Scientists investigating the beta minus radiation had known that during beta minus emission, the nucleus emits an electron. However, it was found that the emitted electron could have a range of energies during any given type of collision. However, according to the laws of conservation of energy and momentum, the emitted electron could only occupy one particular energy if only two particles (the nucleon and the emitted electron) were involved. It turns out that there is, in fact, an additional particle that is released, which conserves both energy and momentum of the system.
The particular type of particle emitted from the nucleus is called a neutrino (In fact, during the beta minus emission an antineutrino is given out, which is the antiparticle of a neutrino). Neutrinos have no charge and they have an extremely small mass (the Nobel Prize in Physics for 2015 was awarded to Arthur B. McDonald and Takaaki Kajita for showing that neutrinos do indeed have mass). Neutrinos hardly ever interact with matter because they are neutral and very light. Actually, about a trillion neutrinos pass through your body every second without you even knowing about it!
Canadian physicist Arthur McDonald (shown above), along with the Japnese physicist Takaaki Kajita (not shown) won the 2015 Nobel Prize in Physics for showing that neutrinos have mass.
In the Standard Model, neutrinos are classified as a type of fundamental particle: they are one of the basic constituents of matter and they are not made of anything else themselves. They are classified as leptons and they come in three different varieties: electron neutrinos, muon neutrinos and tau neutrinos. They have the ability to transform themselves from one of these varieties to another. Neutrinos are produced in the Sun as a result of nuclear fusion taking place at the core. Neutrinos are also produced in the Earth’s atmosphere when cosmic rays strike atoms making up the Earth’s atmosphere. When massive stars collapse and explode as supernovae, large numbers of neutrinos are released.
What is the difference between Neutron and Neutrino
Classification of Particle
Neutrons are made of quarks, therefore they are classified as hadrons.
Neutrinos are fundamental particles and are not made of anything else. They are leptons.
Mass
Neutrons have a mass of about 1.7×10-27 kg.
Neutrinos are extremely light and have a mass of about 10-37 kg.
Interactions
Neutrons do not interact with matter as much as protons do because they are not charged. However, because they are massive they can interact with matter fairly often. Outside the nucleus, they have a mean lifetime of about 880 seconds.
Neutrinos are uncharged and they are not very massive so they interact with other matter very rarely. They are thought to be stable particles.
Image Courtesy
“James Chadwick” by Los Alamos National Laboratory (Los Alamos National Laboratory) [Public Domain], via Wikimedia Commons
“Arthur B. McDonald in 2008” by Boardhead (Own work) [Public Domain], via Wikimedia Commons
