Monday, June 10, 2019

There Is No Experimental Or Observational Evidence To Support A Zero Aggregate Baryon Number At T=0

A recent physics paper described for the first time (at the more than five sigma discovery threshold in a reputable peer reviewed physics journal) CP violation in charmed hardon decays that they had measured to the precise degree predicted by the Standard Model of Particle Physics. The paper is R. Aaij et al. (LHCb Collaboration), "Observation of CP Violation in Charm Decays." 122 Phys. Rev. Lett. 211803 (May 29, 2019).

In response to this paper, I noted at the Physics Forums (underlined emphasis added in this post):
Basically, this is just one more confirmation of a Standard Model prediction, made possible by improved experimental detection capacity at the LHCb. 
The introduction of the Letter notes that:
The noninvariance of fundamental interactions under the combined action of charge conjugation (C) and parity (P) transformations, so-called CP violation, is a necessary condition for the dynamical generation of the baryon asymmetry of the universe. The standard model (SM) of particle physics includes CP violation through an irreducible complex phase in the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix. The realization of CP violation in weak interactions has been established in the K- and B-meson systems by several experiments, and all results are well interpreted within the CKM formalism. However, the size of CP violation in the SM appears to be too small to account for the observed matter-antimatter asymmetry, suggesting the existence of sources of CP violation beyond the SM. The observation of CP violation in the charm sector has not been achieved yet, despite decades of experimental searches. Charm hadrons provide a unique opportunity to measure CP violation with particles containing only up-type quarks. The size of CP violation in charm decays is expected to be tiny in the SM, with asymmetries typically of the order of 10^−4 − 10^−3, but due to the presence of low-energy strong-interaction effects, theoretical predictions are difficult to compute reliably.
The observed amount of CP violation of just the magnitude that the Standard Model predicts: 
(−15.4 +/- 2.9) × 10^−4 
The paper notes in its conclusion that:
The result is consistent with, although in magnitude at the upper end of, SM expectations, which lie in the range 10^−4 − 10^−3. In particular, the result challenges predictions based on first principle QCD dynamics. It complies with predictions based on flavor-SU(3) symmetry, if one assumes a dynamical enhancement of the penguin amplitude.
The researchers belief that it is likely that there will be BSM phenomena that will explain the baryon asymmetry of the universe is a case of hope triumphing over experience. Every single bit of available empirical and observational evidence suggests that the baryon asymmetry of the universe was part of its initial conditions, and these initial conditions do not violate any requirement theoretically necessary for a consistent cosmology model. But, because a Big Bang made of "pure energy" that is then deviated from due to CP violation somehow seems prettier than a non-zero baryon number of the universe to start with, researchers have presumptuously convinced themselves that they must be missing something.
Another very knowledgable participant in the discussion (mfb) responded to the language underlined above stating:
Please name such a piece of evidence, because I think that statement is blatantly wrong (unless you say “0 out of 0 is 100%”).
The post that follows was my response:
1. There has never been an observation of non-conservation of baryon number. This has been tested in multiple processes, e.g. proton decay, flavor changing neutral currents, etc. The experimental bounds on proton decay and neutron oscillation are both very strict. "No baryon number violating processes have yet been observed." Lafferty (2006) citing S. Eidelman et al. (Particle Data Group), Phys. Lett. B592 (2004). 
"Despite significant experimental effort, proton decay has never been observed. If it does decay via a positron, the proton's half-life is constrained to be at least 1.67×10^34 years." Yet, the universe is roughly 1.4*10^9 years old. This experimental result has been a leading means by which GUT theories are ruled out. 
Similarly, neutron-antineutron oscillation is not observed but if baryon asymmetry involves this process there "is an absolute upper limit on the n − n¯ oscillation time τn−n¯ of 5 × 10^10 sec. irrespective of the B − L breaking scale, which follows from the fact that we must generate enough baryon asymmetry via this mechanism (according to the linked 2013 paper). The limit on neutron-antineutron oscillation as of 2009 was τn−n¯ ≥ 10^8 sec. See also confirming the experimental result here
Exclusions for flavor changing neutral currents at the tree level have also not been observed although the measurements are less precise:
In the SM, flavor-changing neutral currents (FCNC) are forbidden at tree level and are strongly suppressed in loop corrections by the Glashow–Iliopoulos–Maiani (GIM) mechanism with the SM branching fraction of t → qH predicted to be O(10^−15). Several extensions of the SM incorporate significantly enhanced FCNC behavior that can be directly probed at the CERN LHC.
In top quark decays they are excluded to a branching fraction of not more than about 0.47% (per the link above). 
2. Likewise, there are no processes which have ever been observed which do not conserve lepton number (e.g. there is no observational evidence of neutrinoless double beta decay). These bounds are very strict already. 
The universe is roughly 1.4*10^9 years old, so the current limit from GERDA (from 2015) means that no more than one in 3.8*10^16 of hadrons that could have done so have actually experienced neutrinoless double beta decay since the formation of the universe. 
3. There has never been an observation of a sphaleron interaction (which would not conserve baryon number or lepton number) but the energies at which sphaleron interactions would take place (about 10 TeV and up) and the rates at which they would occur in the SM (whose parameters and equations are well tested) if they do exist are too small, particularly in light of the small CP violating phase in the CKM matrix (which has been carefully measured). See also, e.g., Koichi Funakub, "Status of the Electroweak Baryogenesis" ("[W]e find that the sphaleron process is in chemical equilibrium at T between 100 GeV and 10^12 GeV.") 
4. It is widely accepted and has been proven that with SM physics (and the linked article below acknowledges), that (1)-(3) imply that the baryon number of the initial conditions is positive and non-zero in the absence of BSM physics of particular baryon number and lepton number violating, CP violating processes that occur (only) out of equilibrium.
These are known as Sakharov’s conditions (Yoshimura is also sometimes given credit for them). This source also notes that:
Another way to view things consists in assuming that the primordial Universe developed through interactions of gravity and other fundamental forces, e.g. through the amplification of vacuum fluctuations. In such a case, gravity being blind to the difference between matter and antimatter, equal initial numbers of baryons and antibaryons are expected, and the current unbalance must be induced by subsequent interactions. . . . We only mention for completeness the possibility that the observed baryon excess is a local artefact, and that the Universe is constituted with domains with either baryon or antibaryon excess. The gamma rays arising from annihilation at the boundary of such domains would be a tell-tale sign, and the fact that they have not been observed rejects such a possibility to the limit of the observable Universe.
See also Paolo S. Coppi, "How Do We Know Antimatter Is Absent?" (2004) (reviewing the evidence against spatial anti-matter domains). 
Thus, no theory of quantum gravity alone can solve the problem unless it has CP violation which no leading theory of quantum gravity does. There is no experimental evidence of CP violation in gravity at the local level. 
In the Standard Model, neither the strong force nor the electromagnetic force have any CP violation either. 
The sole source of CP violation in the Standard Model is the weak force, a force in which the coupling constant gets smaller, not larger, a higher energies (as shown in the famous MSSM gauge coupling constant unification illustration below in the left hand panel; no anomalies in the running of any of the SM coupling constants with energy scale has been observed at the LHC so far), which is the opposite of the direction needed if it is to provide a source of CP violation sufficient to explain the baryon asymmetry of the universe ("BAU") given an assumption that aggregate baryon number at the time of the Big Bang was zero.
See also Wikipedia articles on Baryon asymmetry and Baryogenesis
5. The Higgs boson mass and the associated beta function for it, imply that the SM maintains unitarity up to Big Bang energies. There is nothing that would cause the SM to break down in terms of mathematically if there were no new physics at all at any scale above what is measured and the universe is at least metastable up to the mass (the Higgs boson and top quark masses haven't been measured precisely enough to determine if the universe is stable or metastable if there are no laws of physics other than the Standard Model). See also, e.g., Koichi Funakub, "Status of the Electroweak Baryogenesis" (noting that Higgs boson masses with more than 120 GeV are problematic for models creating BAU from a starting point of zero, when the global average measured value as of 2019 is 125.10 ± 0.14 GeV). 
We know empirically that the SM laws of physics remain valid at least up to Big Bang Nucleosynthesis energy scales (see below) and Large Hadron Collider ("LHC") energy such as those necessary to create a quark-gluon plasma. 
6. No one disputes that the aggregate mass-energy of the universe at the Big Bang was non-zero so it isn't as if there is a precedent that every aggregate parameter of the universe had to be zero at time equals zero (there is dispute, however, over whether gravitational energy is conserved globally in general relativity). 
7. Another quantity that is conserved in the Standard Model locally, and in the aggregate, is electromagnetic charge (for example, e → νe γ and astrophysical limits [m] >4.6 × 10^26 yr, CL = 90%), which still indistinguishable from zero in the aggregate in the universe now, and at all observable times in the history of the universe, and hence, aren't subject to wildly different laws of the universe from the SM if they were zero in the aggregate at the time of the Big Bang. 
This is particularly notable because aggregate baryon number, is equal three times the number of quarks in the universe minus the number of anti-quarks in the universe, and all quarks also electromagnetically charged. Thus, any baryon number violating or lepton number violating process must also be electromagnetic charge neutral. 
8. There are no traces in the predictions of Big Bang Nucleosynthesis that imply that there was not baryon asymmetry in the initial conditions of the universe. Indeed J.-M. Fr`ere, "Introduction to Baryo- and Leptogenesis" (2005) notes that:
based on nucleosynthesis (which occurs late in the history of the Universe and is therefore not too sensitive to the various scenarios – even if it can be affected by the number of neutrino species and the neutrino background) indicate a stricter, but compatible bound: 4 10^−10 < nB/nγ < 7 10^−10.
Any baryon number violating process must take place at T > 200 MeV (the QCD phase transition temperature), otherwise the success of nucleosynthesis will be spoiled. This temperature is about 400,000,000 times the temperature of the Sun and is believed to correspond to a time one microsecond after the Big Bang in the conventional chronology of the universe. One microsecond is about the time it takes a muon to decay. BBN itself is assumed to take place 10 to 1000 seconds after the Big Bang. This temperature is in the ballpark of the highest temperatures arising at the Large Hadron Collider (a temperature scale at which the Standard Model continues to perform as expected in myriad experimental tests). 
Put another way, even advocates of a zero baryon number initial condition (and this would be a majority of theoretical physicists and cosmologists notwithstanding the lack of empirical or observational evidence for it) pretty much agree based upon observation and empirical evidence and well established SM equations and reasonable extrapolations beyond the Standard Model, that the baryon asymmetry of the universe had to be in place around one microsecond after the Big Bang. 
The main reason we can't rule out baryon number violation prior to one microsecond after the Big Bang is that we have no way to observe it. 
9. There are no traces in the CMB that imply that there was not baryon asymmetry in the initial conditions of the universe. (This is unsurprising given that BBN happens much earlier in the cosmology timeline than the CMB traces at t=100,000 years or so). See also the implications of the CMB for inflation
Indeed, both of these windows into the very early universe (8) and (9) imply that if there was not baryon asymmetry at time equal zero, that baryon asymmetry had to completely arise very, very quickly. 
10. As of 2019, all experimentally measured CP violation observed in Nature (apart from neutrino oscillations data where the experimental uncertainties are too great to saying anything more than that CP violation occurs in these oscillations which may be possible to characterize with a single parameter of the PMNS matrix), is defined by a single parameter out of four parameters in all, in the CKM matrix, which as noted above, is insufficient in magnitude to explain the baryon asymmetry of the universe.
The present consistency of global CKM fits is displayed in Fig. 4. Each coloured band defines the allowed region of the apex of the unitarity triangle, according to the measurement of a specific process. Such a consistency represents a tremendous success of the CKM paradigm in the SM: all of the available measurements agree in a highly profound way. In presence of BSM physics affecting the measurements, the various contours would not cross each other into a single point. Hence the quark-flavour sector is generally very well described by the CKM mechanism, and one must look for small discrepancies.

There are also no experimentally measured deviations from CPT symmetry in non-gravitational physics. See generally, Thomas Mannel "Theory and Phenomenology of CP Violation" (2006). 
But see Belfatto, et al. (pre-print 2019) (arguing that there is a 4 sigma tension with unitarity in the measurements of the CKM elements involving the up quark, although such a tension, even if it is more than a fluke measurement wouldn't be remotely sufficient to explain BAU and primarily involves the non-CP violating parameters of the CKM matrix). 
11. Attempts to fit cosmology data to inflation theories allow for only a reasonably narrow number of e-fold (ca. 20-80 at the outside with 40-60 cited more often as consistent with the data), which implicitly imposes strict minimum boundaries on the amount of baryon asymmetry that has to emerge per e-fold since the available time in which cosmological inflation must occur and the available time in which baryon asymmetry must occur if you start from zero aggregate baryon number are basically the same. But, we don't have any indication whatsoever that there is a process that is both baryon number violating and CP violating to the necessary degree, or anything remotely close to that. 
12. We don't need it to get dark energy. Indeed, while the conventional cosmological constant starts with a near zero dark energy and then has it grow proportionately to the volume of space over time, a transition of zero baryon number to massive baryon asymmetry would imply a huge surplus of energy very close to time zero that is not needed to make the Lambda-CDM model (a.k.a. the Standard Model of Cosmology) work. 
13. We don't need it to get 21cm observations to coincide with what is observed. These measure conditions at ca. 300,000 years after the Big Bang so we wouldn't expect them to so signs of baryon symmetry violating processes. 
14. We don't need an initial condition of baryon number equal to zero to get Hubble's constant or a particular amount of dark matter. Assuming a dark matter particle paradigm, according to a pre-print by Yang (2015) subsequently published in Physical Review D, the lower bound on the mean lifetime of dark matter particles is 3.57×10^24 seconds. This largely rules out the possibility that dark matter could bear baryon number and serve as an escape valve around baryon number conservation that is hard or impossible to measure directly. 
There really are no observed phenomena in astronomy or the SM which we need an initial baryon number of zero to explain. Even if the phenomena searched for were "just beyond" current experimental limits, the rates of phenomena like proton decay, neutron oscillation, neutrinoless double beta decay and CP violation beyond the Standard Model, and sphaleron interactions were all observed, so long as the existing experimental results remained accurate, none of these could explain the BAU from a hypothesis that aggregate baryon number was zero at T=0.
A non-zero baryon number as an initial condition is the null hypothesis. It is the conclusion that we reach when we follow the available experimental and observational data, and all experimentally validate laws of physics to their logical conclusion, and assume no modifications of those laws of physics not motivated by empirical or observational evidence. 
To be clear, it isn't impossible that the laws of physics could deviated wildly from the Standard Model at energy scales well in excess of those at the LHC. Lots of respectable physics believe that someday, somehow, we will discover something like this, and almost all published articles in the field of baryogenesis consider the hypothesis that the initial aggregate baryon number of the universe to be "well motivated". Some physicists even assume, without any evidentiary or theoretical consistency support that the initial conditions of the universe must have included a zero baryon number. For example: 
the CP violation in the standard model is a small effect. In particular it is too small to create the observed matter-antimatter asymmetry of the universe, for which CP violation is an indispensable ingredient.
- Thomas Mannel "Theory and Phenomenology of CP Violation" (2006) (emphasis added). 
But, we have no meaningful positive evidence to indicate that not only does this happen, but that the deviation from the Standard Model violates baryon and lepton number, is strongly (basically maximally) CP violating, and only occurs in out of equilibrium systems. Indeed, some of the strongest experimental exclusions in all of physics involve searches for baryon number violating processes and lepton number violating processes.

Arguing for a non-zero aggregate baryon number at the Big Bang isn't glamorous or fun. It's like arguing that the Electoral College is a good idea, or that coal needs to be phased out gradually rather than immediately to prevent the economy from collapsing. But, all existing empirical and observational evidence to date supports this conclusion.
I will be curious to see what kind of response I get (if any).

The "agenda" I am pushing in this post is essentially the same one advanced by Sabine Hossenfelder in her 2018 book "Lost in Math: How Beauty Leads Physics Astray", which which I wholeheartedly agree (the German title, which I prefer, is "The Ugly Universe.").

The notion that the initial aggregate baryon number of the universe must have been zero at the moment of the Big Bang is very widely endorsed by physicists with many prominent ones taking it as an article of faith. But, that is all that it is, a faith based position no supported by an empirical or observational evidence, or any deductions from validated laws of physics, motivated almost entirely by a sense of mathematical beauty that is ultimately in the eye of the beholder.

Like Dr. Hossenfelder, I believe that if hypothesis generation was more closely tied to empirical and observational evidence and deductions from validated theories, and less strongly driven by mathematical beauty, that we would make more progress as a scientific community instead of spending inordinate amounts of time chasing down rabbit holes at great express producing little scientific knowledge of value.


neo said...

interesting points,

what are the implications of a big bang theory where the initial state had baryon asymmetry?

do you think QG theories should have a mechanism to create baryon asymmetry, which means none of the current QG candidates are complete?

what is your theory on matter-antimatter imbalance, as supported by evidence and theories?

what kind of BSM physics respects baryon conservation?

andrew said...

"what are the implications of a big bang theory where the initial state had baryon asymmetry?"

Big Bang theory isn't impaired by an initial state with baryon asymmetry. The two scenarios are indistinguishable after the first microsecond after the Big Bang (which is earlier than any possible direct observation) anyway.

"do you think QG theories should have a mechanism to create baryon asymmetry, which means none of the current QG candidates are complete?"

No. More importantly, I think that pretty much any GUT or TOE that has a mechanism to create baryon asymmetry is probably wrong.

andrew said...

"what is your theory on matter-antimatter imbalance, as supported by evidence and theories?"

My theory, which I've noted in two or three blog posts that cite to journal articles on point is really just pure speculation. But, basically, I think that there are two universes, our universe which starts infinitesimally after t=0 and another universe which starts infinitesimally before t=0 in which the Second Law of Thermodynamics runs backward in time that is antimatter dominated to the same extent that our universe is matter dominated, and that the Big Bang is a time-like domain boundary between the predominantly matter dominated region and the predominantly anti-matter dominated region and the explosive expansion of mass-energy away from the Big Bang in both directions of time is the radiation producing domain boundary that isn't seen in any other part of the post-Big Bang Universe.

Honestly, calling this a theory really dignifies it too. A better word is a conjecture and I think that it is rather unlikely that this conjecture can ever be proven or disproven. But, it is plausible and it ties up the loose ends neatly, and it provides a theoretical option in which there is no reason to look for baryon number and lepton number violating processes, and a way that is aesthetically and philosophically pleasing because it is complete.

At a minimum it is not more speculative and conjectural than a theory in which baryon number and lepton number at t=0 is zero due to BSM physics in the first microsecond after the Big Bang. Indeed, it is such a theory, and indeed, it may very well be the only possible theory that can have a baryon number =0 and lepton number =0 at t=0 without any BSM physics in the observable universe. Thus, you could argue that this is the more timid and less ambitious proposal.

It is motivated by the notion that an anti-particle is mathematically equivalent to a particle moving backward in time. It is also motivated by the fact that the connection between the Second Law of Thermodynamics and underlying particle physics level processes is very subtle and isn't absolute, it is just a statistical reality not a deterministic law. So things that are particles going backward in time (i.e. anti-matter particles) are in a universe that is going backward in time and particles that are going forward in time (i.e. matter particles) are in a universe that is going forward in time. The laws of physics, apart from the Second Law of Thermodynamics (which is not a fundamental law of physics) are the same in both universes.

The point of it is not that we can prove that it is true. The point of its is that it is possible to conceive of a fairy elegant model that describes the universe we see including baryon asymmetry without actually having to break the baryon number conservation law of the SM.

andrew said...

"what kind of BSM physics respects baryon conservation?"

Quantum gravity, asymptotically safe gravity, conformal gravity, modified gravity, dark matter and dark energy theories, with only quite rare and unimportant exceptions, respect baryon number conservation.

Neutrino physics theories in which neutrino mass is entirely Dirac and neutrinos are not Majorana particles tend to also respect baryon number conservation.

Grand Unified Theories (GUTs) which try to fit the three groups of the SM (i.e. U(1), SU(2) and SU(3)) into a single group such as SU(5) or SU(10) or E8, generically, do not respect baryon number conservation, although there may be quite rare and unimportant exceptions.

I'm a less certain about this point, but pretty confident that many SUSY (supersymmetry) and SUGRA (supergravity) theories do not respect baryon number conservation.

String theory/M-theory, which generally involves a GUT and has a low energy approximation that is some form of SUSY in the non-gravitational version, and a low energy approximation that is some form of SUGRA in the gravitational version, does not respect baryon number conservation.

Multiple Higgs doublet theories can but don't necessarily respect baryon number conservation.

Theories with leptoquarks usually do not respect baryon number conservation.

Some preon theories respect baryon number conservation and some don't, depending upon their particle content and the rules for combining them.

The number of dimensions in the universe does not necessarily determine whether or not baryon number is conserved, nor, more generally, do a wide ranges of universe topologies (although I'm sure that there are exceptions).

Graham Dungworth said...

"There Is No Experimental Or Observational Evidence To Support A Zero Aggregate Baryon Number At" or rather in the approach to T=0.

For the casual visitor who may stop by this thread you are welcome to tarry a while and read on as long as you may wish.

A well cited, now countless reams of debate, of how the Heavens and Earth rose out of chaos for sentient beings to wonder about alternatives to Creation that rivals Greek mythology.Geological complexes, also incapable of resolution, were often buried in the deep bosom of the oceans covered, beyond exploration and interpretation.

Prior cosmic density pre and post Planck time,Planck length and Planck mass set the stage of creation. Of the estimated 10^22 ( one of Fred Hoyle's magic cosmic numbers) stars in 10^11 galaxies; their nuclear particles and myriad brethren, photons and leptons and whateverelsons were brooding in a rather tiny abyss of size and temperature. A micron of time is an eternity compared with the Planck unit of time. By the time this timely micron is enacted, the progenitors of all that we now observe were all present.

This all comes about because of a remarkable conclusion about the cosmic background radiation, called photons or particles of light. There should be, in this hot creation enactment, as many photons as nuclear particles. To complicate things there are anti particles too and here on Earth and in the stars and heavens in general these are always created as pairs; protons and antiprotons , neutrons and antineutrons, electrons and antielectrons(positrons) in exactly and precisely equal numbers. These antiparticles or antimatter are never observed naturally in the universe. Accountants like accurate bookeeping and refer constantly to particle numbers. The heavy nuclear particles such as protons and neutrons are referred to (not to forget their anti partners) as baryon number. Wherever we look in the night sky and at opposite sides to the cosmos we empirically observe about 1 billion photons per nuclear particle, with energies equivalent to a thermal temperature of 2.725, precise to a thousandth of a degree. The baryon number is ca. 10^-9 !!!
During the Creation(creation) event for every baryon at the particle threshold temperature for its particle pair production, there should be a partner photon.
Below this temperature the particle antiparticle pair would annihilate to photons at that energy scale. The baryon number should be zero; of course we wouldn't now exist. so what went wrong or rather thank the gods it never happened. This tiny number has perplexed cosmic theorists for sixty years and continues unabated. Where do we dump antimatter? There are now many possibilities, far more than particle numbers of the universe; the latest count is >10^2700, way beyond a googol of possible multiverses.
Every particle with mass has a degeneracy pressure and plays its role in determining stellar masses and processes, a consequence of its particle pair threshold temperature. Stars are hot, nothing like as hot as the approach to a beginning. Barygenesis occurs much later than this timely scenario of the big Bang or Inflation era. It's all a rivetting account that rivals Homeric Epic, a scientific epic that surpasses all prose or rhyme.

Graham Dungworth said...

"what are the implications of a big bang theory where the initial state had baryon asymmetry? "
The known initial conditions and the uncertainty of any hidden assumptions that may exist include the following.

All the rest massive particles including the massive bosons of the electroweak mechanism(Ws and Z)have associated pair production temperatures. These temperatures are huge, much much higher than those temperatures associated with the core temperatures of almost all stars.

The pair production temperatures for protons and neutrons is ca. 11*10^12 Kelvin. Electron positron pair production occurs at a far lower temperature ca. 6*10^9 Kelvin and does occur occasionally in some high mass stars undergoing a supernova type explosion. Associated with pair production is a quantum degeneracy pressure which is able to temporarily resist the tendency of gravity to compress the hot plasma to eventual infinite density via white dwarf, neutron star or black hole formation.
At temperatures above ca. 10^12K , ie. above the threshold for particle pairs such as protons and neutrons (don't forget their antiparticles) the plasma is at equilibrium. These are the baryons. Leptons include their charged particles, electrons and positrons ( and their cousins muons and tauons; indeed the 3 generations of particles, in total over 60 of them! with the quark and antiquark varieties). All of these particles are in dynamic equilibrium. Well before a micron of time had elapsed, infact at around 10^-24 seconds, at temperatures perhaps ca. 10^16 Kelvin, the Z and W massive bosons were also in equilibrium. For every nuclear particle there was a photon or massive boson also in equilibrium. Was there a slight excess of a baryon or anti baryon, or a lepton or antilepton? mfb asks whether there could be a slight excess of electric charge. The electric force is some 10^36 fold stronger than the gravitational force between electrons, a billion so more fold for a 1 meV electron neutrino and antineutrino.
Can a whole galaxy exhibit a slight imbalance of charge ?. Some edgeon galaxies we observe a slight warping of their arms. But the universe has to be electrically neutral on the whole, unless there are other universes out there. There are ca. 10^80 baryons out there, supposedly the 4% of what we observe. A kg of rock has more than an Avergadro number of atoms. The moon but an 83 rd part mass of that for the Earth wouldn't orbit our planet. So even after a huge elapse of time 10^-24 second past an Inflaton Era there exists baryon symmetry. It has to be true for the 4 Higgs fields and their particles that include the Higgs boson and its antiHiggs companion. The Higgs field crystalise out, and they have been switched on ever since. Could it perchance switch off? Not in the last 14 billion years, otherwise everything that ever existed would have vapourised and fled off at the speed of light and we wouldn't exist. These anthropic arguments have plagued us ever since Fred Hoyle queried that slight mass excess of the neutron versus the proton ,electron and neutrino. It's a mass hierarchy, fine tuning problem that continues unabated and has lead to perhaps a vast numerosity beyond measure of multiverses and parallel universes, riveting stuff for the film industry.

Graham Dungworth said...

Of all the hidden assumptions that plague a scientist, this one is the greatest as the scene is set for the most gargantuan historical bang that ever happened, the Big Bang. That's why history is the most important subject of all; it concerns that, of all the things that could have happened, it records what actually did happen.

The particle pairs below their production temperature start to annihilate. Ingrained is the universal expansion, as the size doubles , density drops as the cube of size and temperature inversely to size halves as the observed universe today progressively doubles in size. What we observe today is an asymmetry, 1 billion to 10 billion photon per baryon whereas we should observe a baryon number of one baryon per photon. No known mechanism has ever been found to explain this disparity. There are other problems too, other than this baryon asymmetry. There's the horizon problem, the cmb profile at opposite ends of the celestial sphere should be imbalanced, but the cmb temperature at 2.725K appears too perfect. Inflaton theory attempts to answer the problem(s) but creates mass at constant density at a much earlier time 10^-35 second and cannot address the antimatter problem. If annihilation didn't happen then where is it now? A geologist always knew where to bury a problem. To dump this stuff in an antiuniverse - come on!
Of all the impossible places to consider. As a consequence of degeneracy masses and quantum pressures Fred and Paul got busy with some of those mystical big numbers, namely 10^57, 10^22, 10^79 inter alia eg. baryons, astronomical numbers of numerosity, mass and size.
Neutrinos were not thought to have rest mass so were well not part of the problem, an assumption, not known to exist, not even hidden.
What about the scale sizes. Is not the observable ratio of universe size to black hole or neutron sizes ~10^22 and the numerosity of these small sized beasts with the magic numbers of universe total baryons to neutron numerosity in neutron stars , 10^79/10^57 = 10^22
Black holes are an excellent place to store antimatter. They solve the entropy problems of multiple creations as an added location. Big Bang expansion violates the 2nd law of thermodynamics. Dump the antimatter in black holes and regain paradise, a place fit for sentient beings.
Neutrinos are now known to have rest mass but we must still await empirical measure; it's the 10th anniversary this month of predicted masses. What we need to know are particle pair production temperatures and then ask of neutrino degeneracy masses and pressures. A ca. 1 meV predicted electron neutrino rest mass might radically alter the concept of the Big Bang and challenge the relation of these relic photons/baryon ratio

andrew said...

Observation. Light travels 57 millimeters in one microsecond. (Inflation proposes a more rapid expansion than that at the outset.

Graham Dungworth said...

The key points here Andrew is that in the BB scenario the expanding universe conforms according to a size scale (R) or R for radius =c*t that dilutes as R cubed and a temperature ca. 10^12 Kelvin (just above the threshold temperatures for baryons). Temperature drops as inverse R doubles, so the mass energy density falls 8 fold for each doubling of size. What is the maximum of the BB? There's a problem here, namely the numerosity of new particle types, eg.SUSYs,DMs,monopoles etc. Take your pick 10^6K or 10^32K. All mass energy now observed was present in a former spatial size - for the BB ca. 1 light year at a cosmic density a billion fold of that of water, light travel time a hundredth second and a mere 300km

The many inflaton models incorporate 50-100 size doublings around the time frame of 10^-35 second above 10^32Kelvin at 10^32 K? at constant density! All that we observe now was confined to this sub sub nuclear size. Why?
One has to account for the horizon problem; the fact that this equilibrium requires causal contact. The BB and Inflation both admit that in reality the Universe may be infinate in extent. It's happening everywhere, all the time but from our reference point and all reference points in our universal patch(es) we see no edge effects (no concept of a boundary) and light from these multiverses has not had time to reach us. There are other problems too that arose before both SMs were conceived either for cosmology or the Ui, SU(2) etc for particle physics.
The cooling curves differ somewhat but from H for Hubbles constant one follows the cooling down from enormous temperature and time. AH! the cmb is measured at ca. 3K and note ie. interpolate , that was when it all happened ca. 10 to 20 billion years ago, or 14 billion years +-10% or 8% or <1% if you more mind Hubble deep space results.
There were many prior predictions of cmb temperature within an order of magnitude with what was discovered so it's not surprising that ca. 3K was preclaimed as a victor to other models of cosmic origin(s).

Mass hierarchy had a semi classical origin. Given the measured masses of the electron, proton and neutron and the fact that the neutron mass was only slightly greater by a facor of ca. 1/1000 than the proton and electron combined, a slight change of the fine structure constant and these equilibrium mixes upon cooling would radically change the composition and timing of events. All might condense to neutron stars and black holes within seconds, or end up as pure photon and neutrino radiation. The first to raise these anthropic mysteries with added c12 and O16 nuclear resonances was Fred. For him, what what later coined as the multiverse was a far richer scenario than what we observed restricted to our own. The inflaton field equations they created were his own, alternatively interpreted as the Steady State. I'm not by any means promoting this outdated theory but some of his components reamain apposite today.

Light might travel 57mm in 10^-6 second today (it's Fathers' day here in the UK but my great grandmother taught that Father's day is every day) and it may have travelled much faster then ( I personally don't accept it) but Inflation requires superluminary expansion and constant density inorder to catch up with a BB scenario at R=1 light year. What happens if that cmb temperature correspond to a particle threshold temperature? that it's not just a point interpolated from a thermal cooling curve with an origin, a dodgy temperature maximum?

The repercussions are far worse than a no deal Brexit outcome or a Trump cold loser scenario.