Would proton decay allow for black holes?

[Duda Jarek]

There is considered hypothetical decay of proton - usually into positron and neutral pion, which quickly decays into two photons.

Such decays would allow standard matter to completely change into EM waves (proton + electron -> ~4 photons).

So this decay allow to get to more stable state and temperatures in collapsing neutron stars should make it easier - it suggests that neutron star instead of creating a mysterious matter state (black holes), should 'evaporate' - turn its core into photons ...

 

I've looked at a few papers and I haven't found any considered this type of consequences?

If this process requires extreme conditions to be statistically important, it would happen practically only in the center, heating the star ...

It doesn't contradict Big Bang as a Big Bounce (it cannot change difference between amount of matter and antimatter)

Maybe it could explain extremely high energetic cosmic rays? (maybe in extremely high temperatures high energy photons could itself destroy proton + electron structure, absorbing part of their energy...)

 

 

What do you think about proton decay?

If it would be true - would black holes be created?

Edited December 25, 2009 by Duda Jarek

[swansont]

Having bound particles changes the conditions — the particles are in a lower energy state.

[Duda Jarek]

Particles are some local energy minimals, but there is always lower energy state than any particle - no particles.

States prefer to deexcitate to lower energy state, radiating the difference in form of photons (the deeper local energy minimum, the higher energy barrier and so the more difficult this deexcitation is).

The higher the average energy (temperature) the easier these deexcitations/decays are (lower expected life time).

 

If the baryon number doesn't have to be conserved, matter instead of creating infinitely energy density state in a black hole, should decay into nothing, emitting its energy in form of photons ...

[timo]

I am not completely sure why you think that a proton decay would cause neutron stars to evaporate. I do not think that neutron stars collapse to a black hole either. I think they are pretty stable (but I am not expert).

 

Anyways, let's talk numbers:

a) The prospected lifetime of a proton vs. the estimated age of the universe: ~10^30 years vs. ~10^10 years. In other words: The amount of protons that did decay since the start of proton existence is zero for most practical purposes.

b) The total energy of a nucleon is 1 GeV. You're not going to get more energy out of a nucleon decay (actually less but that will depend on the reaction mechanism you have in mind). Compare that to your "highly energetic cosmic rays" you had in mind: Is that enough?

[Duda Jarek]

Decay is going to some lower energy and so more stable state - what normally stays on the way for such natural process is some energy barrier ... so the higher temperatures (average energy), the easier the decay ... and in inner core of neutron star are achieved kind of maximal temperatures available for standard matter ... so proton decay could be some kind of nature's failsafe to avoid infinite densities ...

 

About ultra-high-energy cosmic rays ... if proton can decay, for example:

- while fast gravitational collapse, start of importance of this decay could be rapid, so that it would cause explosion with much higher energetic particles than from standard supernova, or maybe

- while slow collapse, GeV scale photons created while proton decay could in such extreme conditions destroy internal structure of neutrons (or proton-electron pairs), absorbing its energy and growing into astronomical energies ...

[timo]

Any idea of how nature works is promising until you start to plug in numbers.

[Duda Jarek]

For many different models we can fit parameters so that for example it's first approximations suit well observations ...

I value higher theory's integrity - when it's full consequences qualitatively agrees with what we observe, then it's worth to fit it's parameters ...

 

For example: has general relativity been confirmed better than up to the first approximation (gravity, time dilation, gravitational lensing, Mercury precession)?

The consequences of intrinsic curvature it introduce are enormous - it allows for wormholes ... it says that we live in infinitely thin submanifold of something, completely don't interacting with it ...

Lorentz invariant gravitation can be introduced much simpler in flat spacetime - by second set of Maxwell's equations (with e.g. mass density instead of charge density), time dilation can be explained e.g. by rescaling a bit masses, charges, spins in gravitational potential, what would in first approximation rescale the whole matter making that EM interactions are transfered faster (5th section of http://arxiv.org/abs/0910.2724 )

[timo]

You don't seem to fit parameters or make first approximations.

[Duda Jarek]

Because I'm still thinking about its qualitative consequences - like that it also allows for proton decay in extremely high temperatures, what could solve problems with black holes with its infinite densities ...

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Merged post follows:

Consecutive posts merged

Another argument for proton decay: how nonzero total baryon number in observed universe (matter-antimatter asymmetry) could be created, if baryon number was always conserved?

Edited December 26, 2009 by Duda Jarek

[Duda Jarek]

After Stephen Hawking "There are no black holes": http://www.nature.com/news/stephen-hawking-there-are-no-black-holes-1.14583

now from http://phys.org/news/2014-09-black-holes.html :

"But now Mersini-Houghton describes an entirely new scenario. She and Hawking both agree that as a star collapses under its own gravity, it produces Hawking radiation. However, in her new work, Mersini-Houghton shows that by giving off this radiation, the star also sheds mass. So much so that as it shrinks it no longer has the density to become a black hole."

 

What is nearly exactly what I was saying: instead of growing singularity in the center of neutron star, it should rather immediately go through some matter->energy conversion (like evaporation through Hawking radiation or in other words: some proton decay) - releasing huge amount of energy (finally released as gamma ray bursts), and preventing the collapse.

Edited September 25, 2014 by Duda Jarek

[Sensei]

There is considered hypothetical decay of proton - usually into positron and neutral pion, which quickly decays into two photons.

 

Do you realize it would have to violate either Baryon number conservation and Lepton number conservation?

[Duda Jarek]

Not me, Hawking radiation means: gather lots of baryons into a black hole, wait until it evaporates (massless Hawking radiation) - and there is this number of baryons less in the universe.

 

Also, if we believe in baryogenesis which create more matter than anti-matter ... it also violated baryon number conservation.

[Sensei]

Not me, Hawking radiation means: gather lots of baryons into a black hole, wait until it evaporates (massless Hawking radiation) - and there is this number of baryons less in the universe.

Hawking radiation is hypothetical.

 

[Duda Jarek]

Have you forgotten to add "in contrast to forming infinite density singularity in large matter concentrations" ?

[MigL]

A white dwarf is sustained by electron degeneracy. I'm sure we all agree on this.

As you try and constrain the electrons into a smaller and smaller volume, you are in effect fixing their position more and more accurately. The Heisenberg Uncertainty principle tells us that at a certain level of compression, the electron is 'fixed' into such a small box that the uncertainty in its momentum, I.e. electron mass times velocity, implies that its velocity could be larger than the speed of light. This is obviously non-sensical. This was the reasoning used by S. Chandashekar to arrive at the limit named after him.

Nature gets around this by collapsing stars too massive to be white dwarfs into neutron stars, where the electrons have collapsed into nuclei, merged with protons, and formed a gravitationally bound mass of neutrons. Since the neutrons are approx. 2000 times heavier than electrons, their velocity can now be 2000 times less than it was for electrons, and still satisfy the HUP. But if the pressure keeps increasing still, we constrain the neutrons to a box small enough that the HUP demands that the uncertainty in their velocity ( momentum ) is larger than c . Now if the neutron could decay into a heavier particle, we could still avoid the black hole stage, but there is no such mechanism. gravitational collapse to a black hole is inevitable.

 

I don't see how decay to the ant-matter counterpart of the original electron ( the positron ), be allowed under these conditions. It would only be possible if compression or constrainment of the neutrons or protons was eased, i.e. LESS pressure.

 

A comment on the ( theoretical because they've been indirectly detected ) impossibility of black hole formation ( Mersini-Houghton )...

 

A Black Hole by necessity, starts at the point of greatest density/compression of a collapsing star, i.e. the center, and it starts small and grows to engulf the collapsing star. The Hawking radiation of a BH increases exponentially as a BH gets smaller, until it vanishes in a powerful gamma ray burst. That means when it is first forming it is emitting massive amounts of radiation. Is this radiation pressure enough to keep the star from further collapse ?

in effect you'd have the curious case of a BH starting to form, but immediately releasing all it energy in a gamma ray burst, then starting to form again and, again releasing all it energy, and so on, and so on.

The star would ultimately radiate away without a BH ever fully forming. I haven't read this paper yet, but is this what it is alluding to ?

This does not, however, agree with ( indirect ) observational evidence, and the mechanism is based on unverified assumptions.

Edited September 29, 2014 by MigL

[swansont]

massless Hawking radiation

 

 

That would seem to be an oxymoron of sorts. Hawking radiation isn't massless, AFAIK. It also doesn't violate baryon number conservation.

[MigL]

I'm not sure either swansont, but since Hawking radiation is generated from particle-antiparticle virtual pairs, it could also be generated by massless particles which have an antiparticle, i.e. not photons. Also, the extreme temperature of an atomic scale black hole could and would generate massive particles which would quickly decay and produce gamma radiation.

This is all external to the horizon, of course.

 

I don't have much faith in baryon conservation either, since the universe is mostly matter. At some time, or under certain circumstances, baryons and anti-baryons were generated and destroyed asymmetrically.

Edited October 1, 2014 by MigL

[swansont]

I'm not sure either swansont, but since Hawking radiation is generated from particle-antiparticle virtual pairs, it could also be generated by massless particles which have an antiparticle, i.e. not photons.

 

The implication is that that this is done exclusively, which is what is implied by the claim of baryon number violation. None of that is supported by anything.

[Sensei]

Hawking radiation is based on original Dirac idea that particle has positive mass (and positive energy), and its antiparticle has negative mass (and negative energy).

 

But it has been experimentally confirmed that antiparticles have positive mass (thus positive energy).

Annihilation of electron and positron is example of this process.

Gamma photons produced by it, doesn't have negative energy.

[MigL]

Not exactly Sensei.

Hawking radiation is a result of Heisenberg's principle.

It is more along the lines that if I owe you $20, then I have negative $20. The $20 bill is still a positive quantity, but ownership makes a difference.

[Duda Jarek]

Indeed the main question here is if the baryon number is ultimately conserved?

Violation of this number is required by

- hypothetical baryogenesis producing more matter than anti-matter,

- many particle models, like supersymmetric,

- massless Hawking radiation - black holes would have to evaporate with baryons to conserve the baryon number.

 

From the other side, there is a fundamental reason to conserve e.g. electric charge: Gauss law says that electric field of the whole Universe guards charge conservation.

In other words, adding a single charge would mean changing electric field of the whole Universe proportionally to 1/r^2.

We don't have anything like that for baryon number (?) - a fundamental reason for conserving this number.

 

Indeed the search for such violation (by proton decay) has failed, but this search was performed in room temperature water tanks.

One of the question is if required conditions can be reached in such conditions: if energy required to cross the energy barrier holding the baryon together can be spontaneously generated in room-temperature water. In other words: if Boltzmann distribution of size of random fluctuations still behaves well for such huge energies.

 

If baryon number is not ultimately conserved, it would rather require extreme conditions, like while Big Bang (baryogenesis) ... or in the center of neutron star, which will exceed all finite limits before getting to infinite density required to start forming the black hole horizon and the central singularity.

Such "baryon burning phase" would result in enormous energy (nearly complete matter -> energy conversion) - and we observe this kind of sources, like gamma ray bursts, which "The means by which gamma-ray bursts convert energy into radiation remains poorly understood, and as of 2010 there was still no generally accepted model for how this process occurs (...) Particularly challenging is the need to explain the very high efficiencies that are inferred from some explosions: some gamma-ray bursts may convert as much as half (or more) of the explosion energy into gamma-rays." ( http://en.wikipedia.org/wiki/Gamma-ray_burst )

So we have something like supernova explosion, but instead of exploding due to neutrinos (from e+p -> n), this time using gammas - can you think of other than baryon decay mechanisms for releasing such huge energy?

 

NASA news from 2 days: http://www.nasa.gov/press/2014/october/nasa-s-nustar-telescope-discovers-shockingly-bright-dead-star/

about 1-2 solar mass star, with more than 10 millions times larger power than sun ... is no longer considered as a black hole!

Where this enormous energy comes from?

While fusion or p+e->n converts less than 0.01 matter into energy, baryon decay converts more than 0.99 - are there some intermediate possibilities?

[MigL]

I think you misunderstood the NASA article.

This pulsar may be smaller in mass than that required to collapse to a black hole, but it is a gravitational sink, just like a BH, and acts just like one. This means it has an accretion disc, just like an active BH, and will radiate as much energy in the X and gamma range as a BH. It is the accelerating, ionized gases spiraling into the neutron star which generate the energy along the axis of rotation ( which may be facing our direction ).

I would assume once this neutron star 'eats' enough mass, it will undergo further collapse to a BH.

[Duda Jarek]

From the NASA article: "Until now, all ULXs were thought to be black holes. The new data from NuSTAR show at least one ULX, about 12 million light-years away in the galaxy Messier 82 (M82), is actually a pulsar. (...) Black holes do not pulse, but pulsars do."

 

If as "a gravitational sink" you mean massive and small - sure.

However, as I understand the NASA article, it is considered being a star: an macroscopic object made of matter, instead of a black hole: all matter being gathered in the central singularity.

The assumption is that there is a rotating object made of matter, producing much more energy than we could explain (assuming baryon number conservation) - what is the source of this energy?

[MigL]

If you were blindfolded and orbiting around a star, or a neutron star, or a black hole, you couldn't tell the difference.

Similarly, if you were ionized gas and being accelerated in the accretion disk of a strong gravitational source.

There is no difference !!!

 

I believe I've already explained the source of the energy.

The NASA article explains that an 'active' pulsar has never been observed before, but many 'active' black holes have been ( every quasar observed ).