
#1
Nov912, 06:39 AM

P: 23

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/201201antimatterlab.html What happened to this experiment? 



#2
Nov912, 09:41 AM

Mentor
P: 10,774

A difference between the masses of particles and antiparticles would ruin significant parts of the Standard Model as it would violate CPT invariance. 



#3
Nov912, 11:06 AM

Mentor
P: 15,571

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




#4
Nov1012, 07:31 AM

P: 23

MatterAntimatter MassAnd also that the difference may be significant? Like 10^6 to 10^9 gram. 



#5
Nov1012, 08:54 AM

Mentor
P: 10,774

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 (quantummechanical 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). 



#6
Nov1012, 08:59 AM

P: 23

Ok. S is there any difference? In the order of 10^27? 



#7
Nov1012, 09:14 AM

Mentor
P: 10,774

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^{38}g 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^{32}g difference). The gravitational acceleration on objects of different composition differs by less than 10^{10}, or 1 part in 100 billions (Eötvös experiment). 



#8
Nov1012, 11:17 AM

P: 23

Ok thank you.



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