Β+ decay: voiding conservation of mass or creating something with negative mass

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Discussion Overview

The discussion centers on the implications of β+ decay, particularly regarding the conservation of mass and energy, and the concept of negative mass. Participants explore whether β+ decay challenges the principle of mass conservation or suggests the existence of negative mass, while also considering its potential role in cosmological expansion.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that β+ decay either disproves mass conservation or implies the generation of negative mass, questioning the validity of negative mass as a concept.
  • Others argue that in nuclear and particle-physics interactions, the sum of rest masses before and after an interaction does not generally equal, emphasizing that conservation of energy is what truly matters.
  • There are inquiries about other interactions where rest mass is not conserved, with a focus on whether energy can be generated without destroying mass.
  • One participant references a previous discussion about stars losing mass and energy over time, questioning the relationship between mass loss and the topic at hand.
  • Another participant raises a question about the efficiency of photons emitted into a star, suggesting that if photons are not intense enough, their energy may be wasted rather than contributing to nuclear reactions.

Areas of Agreement / Disagreement

Participants express differing views on the implications of β+ decay for mass conservation and the nature of energy transformations in nuclear reactions. No consensus is reached on these points, and the discussion remains unresolved.

Contextual Notes

Participants highlight the complexity of energy conservation in nuclear processes, noting that assumptions about mass and energy may vary based on the specific interactions being considered. The discussion reflects a range of interpretations regarding the relationship between mass, energy, and the behavior of stars.

treehouse
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From Wikipedia: "Positron emission or beta plus decay (β+ decay) is a type of beta decay in which a proton is converted, via the weak force, to a neutron, releasing a positron (the antimatter counterpart of an electron) and a neutrino.
Isotopes which undergo this decay and thereby emit positrons include carbon-11, potassium-40, nitrogen-13, oxygen-15, fluorine-18, and iodine-121."
Carbon-11 is used in positron emission topography.

Positrons are massive; therefore, β+ decay either disproves that mass is conserved or generates something with negative mass. How is the concept of negative mass anything other than non-sense?

If the universe is not massive enough to stop cosmological expansion and cosmological expansion could make parts or all of the universe impractical to occupy, could β+ decay be used to control cosmological expansion?
 
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treehouse said:
Positrons are massive; therefore, β+ decay either disproves that mass is conserved or generates something with negative mass.

In nuclear and particle-physics interactions, the sum of the rest-masses of the particles before the interaction does not generally equal the sum of the rest-masses of the particles after the interaction. ß+ decay is far from unique in this.

What counts is conservation of energy: The total energy of the particles before equals the total energy of the particles afterward, provided that you include all the forms of energy: rest-mass energy mc^2, kinetic energy, and potential energy when appropriate.
 
jtbell said:
In nuclear and particle-physics interactions, the sum of the rest-masses of the particles before the interaction does not generally equal the sum of the rest-masses of the particles after the interaction. ß+ decay is far from unique in this..
What are some others?


jtbell said:
What counts is conservation of energy: The total energy of the particles before equals the total energy of the particles afterward, provided that you include all the forms of energy: rest-mass energy mc^2, kinetic energy, and potential energy when appropriate.
But can't we make energy without destroying mass? Aren't there nuclear reactions in which rest mass is conserved which generate thermal energy?
 
One of my other threads got further into conservation than this one: "
nasu said:
What about them? I am not sure what point are you trying to get to.
And from what I know, the stars, if anything, will loose mater and energy over time. Why would you think they get more massive? And how is related to the topic (whatever that is)?
Some stars get less massive; but some stars which emit photons that can push solar sails turn into black holes - and when stars get less massive it is because as part of a nuclear reaction generating an immense amount of energy they eject matter which was previously relatively stationary inside the star." - https://www.physicsforums.com/showthread.php?t=510083
 
If you take energy and use it to emit photons into a star isn't all the energy in those photons lost if the photons are not intense enough to knock electrons off the atoms in the star? Wouldn't the photons just get the electrons in the atoms more excited just to be wasted as the electrons leave the atoms with whatever energy they do in the particular nuclear reaction they are involved in in the star?
 

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