Could Neutrinos Challenge Our Understanding of Physics?

In fact, I am not sure what you mean by "standing wave form" or "circling in a loop". Massless particles travel at the speed of light and their motion can be described by wavefunctions, but I am not sure how that would involve "standing waves" or "circling".
  • #1
star apple
Neutrino is one of the few things that belong to mainstream beyond standard model stuff. I was reading the October 2017 Scientific American article "Neutrino Puzzle" and I have some questions about the following:

https://www.scientificamerican.com/article/the-neutrino-puzzle/

"THE ORIGIN OF MASS
Once they know t he ordering of the neutrino masses, researchers can tackle the larger question of how neutrinos get their mass. Most particles, such as the protons and neutrons inside atoms, acquire mass by interacting with the Higgs field; this field, which pervades all of space, is associated with the Higgs boson found at the LHC. But the Higgs mechanism works only on particles that come in both right-handed and left-handed versions, a fundamental difference related to the orientation of their spin relative to their direction of motion. So far neutrinos have been seen only in left-handed form. If they got mass from the Higgs field, then right-handed neutrinos must also exist. But right-handed neutrinos have never been observed, which suggests that if they are real they do not interact at all with any other forces or particles in nature—and that prospect strikes some physicists as far-fetched. Furthermore, if the Higgs field did work on neutrinos, theorists would expect them to have similar masses to the other known particles. Yet neutrinos are inexplicably light. Whatever the mass states are, they are less than one hundred-thousandth of the mass of the already puny electron. “Very few people think it’s the Higgs mechanism that gives mass to the neutrinos,” says Fermilab’s director Nigel Lockyer. “There’s probably a completely different mechanism, and therefore there should be other particles associated with how that happens.”
"One possibility that excites physicists is that neutrinos could be Majorana particles—particles that are their own antiparticles. (This is possible because neutrinos have no electric charge, and it is a difference in charge that distinguishes a particle from its antimatter counter
part.) Theorists think Majorana particles have a way of getting mass without involving the Higgs field—perhaps by interacting with a new, undiscovered field. The mathematics behind this scenario also requires the existence of a very heavy set of neutrinos that has yet to be discovered; these particles would have up to a trillion times the mass of some of the heaviest known particles and would, in a sense, counterbalance the light neutrinos. For particle physicists, the prospect of discovering a new mass scale is enticing. “Historically we’ve always made progress by exploring nature at different scales,” de Gouvêa says. And if some new field gives mass to neutrinos, maybe it affects other particles as well. “If nature knows how to do it to neutrinos, where else does it do it?” Lockyer speculates. “Theorists are asking: Could dark matter be a Majorana mass?” "

Some questions I'd like to ask:

1. what are the proposals (any papers, references, etc?) for the completely different mechanism of how the neutrino may get mass in addition to Higg mechanism and relativistic energy/mass effects?

2. All massless particles (or near massless particles) were supposed to travel at or near the speed of light. Is there any proposal or papers written where massless or near massless particles, instead of traveling straight are in some standing wave form (like circling in a loop), and how do they do that?

Thank you!
 
Physics news on Phys.org
  • #2
star apple said:
Furthermore, if the Higgs field did work on neutrinos, theorists would expect them to have similar masses to the other known particles.
This is not very accurate. The neutrino Dirac mass would be expected to be similar to the mass of the other fermions. However, being a Standard Model singlet, the right handed neutrino would generally allow for an additional Majorana mass term and there is no a priori way of forbidding it. There would be no a priori handle on the size of this mass term as it would be unrelated to anything we know. It is popular to theorise that this Majorana mass term is significantly larger than the Dirac mass. If that is the case it would naturally suppress the masses of the Standard Model neutrinos and thereby actually explain why neutrino masses are so small. This is known as the (type-I) seesaw mechanism.

star apple said:
“Very few people think it’s the Higgs mechanism that gives mass to the neutrinos,” says Fermilab’s director Nigel Lockyer. “There’s probably a completely different mechanism, and therefore there should be other particles associated with how that happens.”
Truth with modification. The Higgs mechanism is part of the seesaw mechanism and the Higgs is therefore also involved in the seesaw.

star apple said:
Theorists think Majorana particles have a way of getting mass without involving the Higgs field—perhaps by interacting with a new, undiscovered field. The mathematics behind this scenario also requires the existence of a very heavy set of neutrinos that has yet to be discovered; these particles would have up to a trillion times the mass of some of the heaviest known particles and would, in a sense, counterbalance the light neutrinos.
These new particles are exactly the same right-handed neutrinos he talked about before, just with an additional Majorana mass term. The Higgs field is most definitely involved in allowing the heavy mass to suppress the Standard Model neutrino masses.

star apple said:
1. what are the proposals (any papers, references, etc?) for the completely different mechanism of how the neutrino may get mass in addition to Higg mechanism and relativistic energy/mass effects?
Apart from the type-I seesaw mechanism (you should find this in any review of neutrino physics), which involves right-handed neutrinos, there are the type-II and type-III seesaw mechanisms, which involve adding an additional scalar SU(2) triplet and an additional fermion SU(2) triplet, respectively.

star apple said:
2. All massless particles (or near massless particles) were supposed to travel at or near the speed of light. Is there any proposal or papers written where massless or near massless particles, instead of traveling straight are in some standing wave form (like circling in a loop), and how do they do that?
Not that I am aware of.
 
  • Like
Likes star apple and Urs Schreiber

1. What is a neutrino?

A neutrino is a subatomic particle that has a very small mass and no electric charge. It is one of the fundamental particles that make up the universe and is often referred to as the "ghost particle" because it has a tendency to pass through matter without interacting.

2. How was the existence of neutrinos discovered?

The existence of neutrinos was first theorized by physicist Wolfgang Pauli in 1930 to explain the missing energy and momentum in certain nuclear reactions. It was later confirmed in 1956 by Clyde Cowan and Frederick Reines through their detection of the first neutrino in a nuclear reactor.

3. What are the three types of neutrinos?

The three types of neutrinos are the electron neutrino, muon neutrino, and tau neutrino. They are classified based on their associated charged lepton (electron, muon, and tau) and their corresponding antiparticles (antineutrinos).

4. How do neutrinos interact with matter?

Neutrinos have a very weak interaction with matter, making them difficult to detect. They primarily interact through the weak nuclear force and occasionally through the gravitational force. These interactions are so weak that neutrinos can pass through vast amounts of matter without being absorbed or scattered.

5. Why are neutrinos important in the study of new physics?

Neutrinos play a crucial role in the study of new physics because they have properties that differ from other known particles. For example, they have a very small mass, can change their type (flavor) as they travel, and potentially violate the conservation of lepton family numbers. These unique properties provide valuable insights into the fundamental laws of physics beyond the Standard Model.

Similar threads

  • Beyond the Standard Models
Replies
1
Views
202
Replies
1
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
1K
  • Beyond the Standard Models
Replies
6
Views
2K
  • Beyond the Standard Models
Replies
0
Views
835
  • High Energy, Nuclear, Particle Physics
Replies
4
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
3
Views
985
  • High Energy, Nuclear, Particle Physics
3
Replies
80
Views
11K
Replies
4
Views
353
  • Beyond the Standard Models
Replies
1
Views
2K
Back
Top