Exploring the Differences Between Dirac and Majorana Masses

In summary, a Majorana mass is a mass term given to Majorana particles, which are particles that are their own antiparticles and only exist for uncharged fermions in the Standard Model. The only candidate for a Majorana particle in the Standard Model is the neutrino, but it is still unclear whether neutrinos are Majorana particles or Dirac particles. To clarify this, scientists look for evidence of neutrino-less double beta decay. The main difference between a Majorana mass and a Dirac mass is that a Majorana mass only applies to Majorana particles while a Dirac mass applies to all fermions in the Standard Model. It is also possible for a particle to have both a Dirac and Majorana mass term.
  • #1
Trixie Mattel
29
0
Hello,

I am having a real problem trying to figure out what a Majorana mass is.

The only thing I gather so far is that dirac mass is the mass that is the result of the Higgs Mechanism.

What exactly is the Majorana mass, and for which particles does it exist.Thank you
 
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  • #2
Have a look at the following lecture notes. There's a nice explanation of what Majorana fermions are:

https://www.nikhef.nl/pub/theory/academiclectures/QFT2012-Majorana.pdf

In the Standard Model of elementary particle physics all fermions are treated as Dirac fermions. Since only uncharged fermions can be Majorana fermions, because otherwise you'd violate charge conservation (which is bad since if you violate charge conservation you also violate gauge invariance which is at the heart of the standard model), the only candidates of the particles in the standard model for being Majorana fermions are the neutrinos, and it's up to now not clear whether they are Dirac fermions as assumed in the Standard Model or Majorana fermions, i.e., their own antiparticles. To clarify this question one looks for neutrino-less double beta decay:

https://en.wikipedia.org/wiki/Double_beta_decay
 
  • #3
vanhees71 said:
Have a look at the following lecture notes. There's a nice explanation of what Majorana fermions are:

https://www.nikhef.nl/pub/theory/academiclectures/QFT2012-Majorana.pdf

In the Standard Model of elementary particle physics all fermions are treated as Dirac fermions. Since only uncharged fermions can be Majorana fermions, because otherwise you'd violate charge conservation (which is bad since if you violate charge conservation you also violate gauge invariance which is at the heart of the standard model), the only candidates of the particles in the standard model for being Majorana fermions are the neutrinos, and it's up to now not clear whether they are Dirac fermions as assumed in the Standard Model or Majorana fermions, i.e., their own antiparticles. To clarify this question one looks for neutrino-less double beta decay:

https://en.wikipedia.org/wiki/Double_beta_decay
Thank you. So, a Majorana mass term can only be given to a majorana particle, and the only particle that that could possibly be is the neutrino??
But what is the difference really between majorana mass and a dirac mass? Also can majorana particles have both dirac and majorana terms?
 

1. What are Dirac and Majorana masses?

Dirac and Majorana masses are two types of mass terms that can be used to describe the behavior of fermions, which are particles with half-integer spin. These masses are important in the field of particle physics, as they play a crucial role in understanding the properties of fundamental particles.

2. What is the difference between Dirac and Majorana masses?

Dirac and Majorana masses differ in their properties and how they interact with other particles. Dirac masses are associated with fermions that have a conserved quantum number, such as electric charge, while Majorana masses are associated with fermions that are their own antiparticles.

3. How do Dirac and Majorana masses arise in particle physics theories?

Dirac masses arise in the Standard Model of particle physics, which describes the interactions between fundamental particles. These masses are generated through the Higgs mechanism, which gives particles their mass. Majorana masses, on the other hand, are not predicted by the Standard Model and are typically introduced through extensions of the model, such as supersymmetry.

4. What are the implications of having a Majorana mass term in a particle physics theory?

Having a Majorana mass term in a particle physics theory has several implications. One of the most significant is the existence of new types of particles known as Majorana fermions, which have unique properties and can help explain certain phenomena in the universe, such as dark matter.

5. How are Dirac and Majorana masses experimentally verified?

Dirac and Majorana masses can be experimentally verified through high-energy particle accelerators, such as the Large Hadron Collider, where scientists can observe the behavior of particles and measure their masses. Additionally, there are ongoing experiments specifically designed to search for evidence of Majorana fermions, such as the MAJORANA Project, which aims to detect a rare nuclear decay process that would provide evidence for these particles.

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