Particles less massive than leptons?

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Discussion Overview

The discussion revolves around the concept of particles with mass less than that of leptons, exploring the implications of mass and size in particle physics. Participants examine the nature of elementary particles, their mass, and the search for lighter particles, while also addressing misconceptions about particle size.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants inquire whether there have been searches for particles less massive than leptons, suggesting a curiosity about the existence of such particles.
  • Others point out that neutrinos are currently the least massive known particles, questioning the assumption that less massive particles would be larger.
  • There are mentions of ongoing experiments and theories regarding lighter mass particles, including gravitons and photons, although the massless nature of these particles is highlighted as a point of confusion.
  • Participants discuss the concept of elementary particles being point-like, with references to the Planck length and the implications of defining size in this context.
  • Some argue that the notion of a point in physics is not infinitely small, while others challenge the consistency of describing point-like particles with a characteristic length.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between mass and size of particles, with no consensus reached on the implications of particle size or the nature of elementary particles.

Contextual Notes

There are unresolved questions regarding the definitions of mass, size, and the characteristics of elementary particles, as well as the implications of these definitions in the context of particle physics.

granpa
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People are always smashing particles together with more and more energy searching for and finding more and more massive particles.
Have there been any searches for particles less massive (and therefore larger) than leptons?
 
Physics news on Phys.org
At present the least massive (non-zero mass) known particles are neutrinos.

Your comment is a little puzzling - why would less massive particles be larger?
 
Leptons are elementary particles and I believe that article deals with confinement of many particle systems such as the electron clouds and atomic nuclei/Quark Confinement.
 
There are tons of people out there doing tons of experiments. Odds say some are looking for said particles. There are some theories about lighter mass particles which are being searched for (graviton, photon, etc.)
 
Gravitons and Photons are massless so you can't compare it to a particle like a Neutrino or any other massive particle for that reason. It's like saying what's less least massive known apple? A kiwi, it's unassosciative.
 
mathman said:
At present the least massive (non-zero mass) known particles are neutrinos.

Your comment is a little puzzling - why would less massive particles be larger?

<br /> \lambda= { \hbar \over m c}<br />
 
I thought all elementary particles are point like, and their size is the Plank Length or around there.
 
Constantin said:
I thought all elementary particles are point like, and their size is the Plank Length or around there.

That statement is contradictory. How can something be pointlike and at the same time be characterized by some length?
 
  • #10
Because a point in physics is not infinitely small.
Plank length is the shortest measurable length.
 
  • #11
Constantin said:
Because a point in physics is not infinitely small.
Plank length is the shortest measurable length.
Whilst the latter statement may be true, the former isn't. A point is a point. The notion of a "point" in physics is not distinct from topological notion of a point.
 
  • #12
Constantin said:
Because a point in physics is not infinitely small.

If a point is not infinitely small (zero dimensional), it's by definition not a point.
 

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