The fundamental experimental evidence for the equivalence of rest mass and energy commonly written in an equation (without hand waving) E = mc2 can be found in comparing the masses of the nuclei before and after a fission reaction, where the difference goes into the energy release. The measurements are not off by a factor of 2.
see https://www.dummies.com/article/academics-the-arts/science/physics/nuclear-fission-basics-200956
Careful measurements of atomic mass predate experimental fission. See "History" section of
https://www.newworldencyclopedia.org/entry/Atomic_mass
I am not allergic to E=mcc. I am allergic to the Einstein derivation.
But if tests lean towards E=mcc rather than E=mcc/2 then i am happy with that. There is a slight chance of having a circular argument on both sides of the equation, but i can accept that that can be ruled out with good tests. But the Einstein derivation is a circular argument, as shown by Ives. The real problem is of course that no-one knows what E=mcc really means. Einstein changed his mind on this as the years went by, as of course u will be aware. But skoolkids are still taught that mass increases with speed.
If you are going to disagree with a standard equation, you should quote it correctly instead of attacking a straw man.
In special relativity, the equation for the energy of a mass in motion is
E = (moc2) / [1 - (v2/c2)]1/2
When the velocity is 0, this reduces to the famous E = moc2 .
The rest mass mo is the mass of the object at rest, and is invariant.
At low velocity, v << c, freshman mathematics shows that the equation is a close approximation to
E = (moc2) + (mov2/2)
where the first term is the mass-energy and the second term is the classical (non-relativistic) kinetic energy.
Dividing mcc by gamma is equivalent to (smells like) invoking mass increase. Its also equivalent to other things.
Aetheric relativity (my version at least) also uses gamma in strange ways.
I said that aetheric relativity says that E=mVV/2. And that V has a possible limit of 2c. That is correct, in the absolute aetheric reference frame. This means that an observer (Stan) who is stationary in the aether (ie the aetherwind blowing through him is zero km/s) could use that equation. But, Roxanne, on the rocket, looking out of a window, might feel/see a different speed, & she might need a different equation.
Roxanne's route has (static) km markers, & she counts 260,000 in 1.0 second, so she reckons that her V is 260,000 km/s (ie 0.8660c). And she calculates that her E is mVV/2. But, she is using her on-board atomic clock, & the aetherwind blowing through her rocket & clock is 0.8660c. We assume that the ticking of an atomic clock is slowed due to the length contraction that it suffers as the aetherwind increases, & that the slowing is in accordance with the standard Lorentz gamma, which for ticking is actually the Larmor gamma (Larmor was the first to invent the equation)(which he based on an electron's atomic orbit), where the V is the aetherwind. So, her clock ticks slower than Stan's atomic clock. Gamma is (1 – VV/cc)^0.5, which is (1-0.8660*0.8660)^0.5, which is (1-3/4)^0.5, which is (1/4)^0.5, which is ½. So, her true speed was not 260,000 km/s, it was 130,000 km/s. This is the speed that Stan would have measured, ie the true speed (ie the absolute speed)(ie in the absolute reference frame). So, her naïve calculation of her E would in this instance overestimate her E (kinetic energy) by a factor of 4. But, Roxanne is not naïve, & she would correct her V' to true V.
In addition to the aetherwind suffered by Roxanne's rocket, Roxanne knows that the aetherwind blows into the very large planet where she is carrying out her tests, koz aether is annihilated in mass. Aetherists assume that the aetherwind inflow is equal to the escape velocity for the planet, which for this very large planet happens to be 260,000 km/s. Earth's escape velocity is 11.2 km/s (not important). Stan knows that the inflow aetherwind slows the ticking of his clock, & he knows that his clock ticks at a half of the true ticking, & he knows that Roxanne's speed was actually 65,000 km/s. Earlier i said that the aetherwind blowing through Stan was zero km/s, but i lied so as not to complicate things for u fellows too early.
Now, Roxanne too knows that there is an inflow aetherwind. Her clock has an aetherwind of 260,000 km/s due to her speed V, & an aetherwind of 260,000 km/s due to the inflow v. So, her aetherwind is the vector sum which is 368,000 km/s, & so the gamma for her atomic clock should be based on that V. Unfortunately for Roxanne 368,000 km/s is faster than c, & aetherists know that a particle can't achieve the speed of light (relative to the aether)(ie sort of in agreement with Einsteinist's here). So, i should have picked a slower (non-impossible) speed for Roxanne's rocket in the first instance. But i wont bother to go back & fix things, everyone here gets the drift. The point is that the true ticking of her atomic clock will depend on her true aetherwind. And, she knows all of that, & she knows that she needs the 2 corrections.
But, there's more. There needs to be a 3rd correction. Einstein's GTR predicted that light is slowed near mass. And that the slowing is equivalent to having a gamma where u insert the escape velocity (say v") for the V in the VV/cc in the equation for gamma, in which case gamma contains v"v"/cc. Aetherists assume that this slowing of light also applies to the slowing of em forces acting in & tween atoms, & that it affects electron orbit, & that it slows the ticking of atomic clocks. Aetherists also assume that Einstein's equation for his gamma here has the correct form, even though Einstein used faulty reasoning for the derivation. Aetherists are happy to call this the Einstein's atomic ticking gamma. Stan knows that Shapiro confirmed Einstein's slowing of light near mass idea, now called Shapiro Delay. And Stan knows that all of this accords with the Larmor gamma for atomic ticking (alltho Larmor based his gamma on the aetherwind, not the nearness of mass). So, Stan knows that his atomic clock has to have an initial correction, using 260,000 km/s in the Einstein's (atomic ticking) gamma. So, Stan's clock's true ticking is double the actual ticking. One second on Stan's clock is actually 2 seconds of true time. True time being the rate of his clock when not near mass & when the aetherwind is zero km/s. The first correction for an atomic clock is (should be) the correction for the nearness of mass, & this has nothing to do with aetherwind, & it has nothing to do with gravity, it is due to the nearness of mass (i wont explain the cause of this stuff today). Earlier i said that this was a 3rd correction, in fact it should be the first correction, after which we can add the corrections (2 ovem) for the aetherwind.
So, Stan's calculation for Roxanne's speed tells him that she is moving at 32,500 km/s. Stan used 2 corrections, one for the nearness of mass, & one for the aetherwind inflow into the planet. Funnily enuff both corrections are identical (in this instance)(but not in some other instances that could come up)(which i could explain)(but not today), so we can simply apply the gamma twice. We can't take the shortcut of adding the escape velocity to the escape velocity & using the equation once. That duznt work. In fact that would not be a shortcut anyhow, the proper procedure is simpler anyhow.
Roxanne had to use the same 2 corrections that Stan used, but her correction for her aetherwind was complicated koz she had to allow for her speed (Stan's speed is zero km/s), in effect a 3rd correction for her.
Einsteinists don’t correct for any of these proper corrections. They in effect correct very crudely for Roxanne's speed by using her relative velocity relative to Stan, & if Stan is indeed static in the aether then this can in some cases give a result similar to the true number. The Einsteinian numbers are however starting to be seen to fail, in the modern super accurate era of science, & aetheric relativity is now needed, or soon will be.
Anyhow, i apologise for attacking a strawman.