Does Antimatter Have More Mass Than Matter?

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Discussion Overview

The discussion centers around the question of whether antimatter has more mass than matter, exploring the implications of mass measurements and gravitational effects in particle physics. Participants reference experiments and theoretical considerations related to the Standard Model and CPT invariance.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • Some participants assert that no experiment has conclusively measured a difference in mass between matter and antimatter, suggesting that any difference would violate CPT invariance.
  • Others propose that while mass measurements are precise, gravity measurements in particle physics are complicated due to the weak nature of gravity.
  • One participant mentions that it is impossible to know if two particles have the "EXACT same mass," and that limits can only be set on the differences.
  • There are suggestions that antimatter could exert a greater gravitational force on matter, with some participants speculating on the significance of any potential mass difference, estimating it could be in the range of 10^-6 to 10^-9 grams.
  • Another participant provides numerical limits on the relative differences in mass between particles and their antiparticles, indicating that any difference is extremely small, on the order of 10^-27 grams or less.

Areas of Agreement / Disagreement

Participants generally agree that no experimental evidence currently supports a difference in mass between matter and antimatter, but there are competing views regarding the implications of potential differences and the nature of mass versus gravitational measurements.

Contextual Notes

Participants highlight the distinction between mass measurements, which are precise and based on rest energy, and gravity measurements, which are more challenging and could violate established principles like the equivalence principle if differences were found.

Shailank
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Does antimatter has more mass than matter?

Its not conclusively proven that they have the EXACT same mass. Also i read about an experiment being conducted. http://phys.org/news/2012-01-antimatter-lab.html
What happened to this experiment?
 
Physics news on Phys.org
Does antimatter has more mass than matter?
No experiment measured any difference.
A difference between the masses of particles and antiparticles would ruin significant parts of the Standard Model as it would violate CPT invariance.

What happened to this experiment?
That could take a while. Gravity is hard to see in particle physics as it is extremely weak.
 
One will never know that two particles (any two) will have the "EXACT same mass". We can only set limits on the difference.
 
mfb said:
No experiment measured any difference.
A difference between the masses of particles and antiparticles would ruin significant parts of the Standard Model as it would violate CPT invariance.


That could take a while. Gravity is hard to see in particle physics as it is extremely weak.

Vanadium 50 said:
One will never know that two particles (any two) will have the "EXACT same mass". We can only set limits on the difference.

Yeah so it can be possible that that antimatter excerts a greater gravitational force on matter and vice versa?

And also that the difference may be significant? Like 10^-6 to 10^-9 gram.
 
You have to distinguish mass measurements from gravity measurements here.

Mass measurements are common in particle physics - it is a measurement of the rest energy of the particle. Those are very precise, especially for stable particles and antiparticles. Any difference would violate CPT invariance (quantum-mechanical statement)

Gravity measurements measure the influence of gravity. Those are tricky in particle physics. Any difference would be a different gravitational acceleration and violate the equivalence principle (from General Relativity).

And also that the difference may be significant? Like 10^-6 to 10^-9 gram.
If there is any difference at all, it has to be at the level of the particles itself, of the order of 10-27 gram.
 
mfb said:
You have to distinguish mass measurements from gravity measurements here.

Mass measurements are common in particle physics - it is a measurement of the rest energy of the particle. Those are very precise, especially for stable particles and antiparticles. Any difference would violate CPT invariance (quantum-mechanical statement)

Gravity measurements measure the influence of gravity. Those are tricky in particle physics. Any difference would be a different gravitational acceleration and violate the equivalence principle (from General Relativity).


If there is any difference at all, it has to be at the level of the particles itself, of the order of 10-27 gram.


Ok. S is there any difference? In the order of 10^-27?
 
mfb said:
No experiment measured any difference.

To add some numbers:

The relative difference between electron and positron mass (if there is a difference at all) is smaller than 8*10-9, or 8 parts in a billion (<10-38g difference).
The relative difference between proton and antiproton mass (if there is a difference at all) is smaller than 2*10-9, or 2 parts in a billion (<10-32g difference).

The gravitational acceleration on objects of different composition differs by less than 10-10, or 1 part in 100 billions (Eötvös experiment).
 
Ok thank you.
 

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