matter antimatter asymmetry ??

[Widdekind]

Are anti-matter particles ever-so-slightly more massive, than matter particles ? I understand, that our universe contains 7x as many protons, as neutrons, because the former are less massive, and so were 7x more numerous, at the temperature, when baryons became bound into nuclei, i.e. Boltzmann factor [math]e^{-\frac{\Delta E}{k_B T}}[/math]. If the matter-antimatter asymmetry, related to the baryon-to-photon ratio [math]\eta \approx 10^{-10}[/math], arose when the universe was approximately the temperature-equivalent of Weak bosons [math]\approx 100 GeV[/math], then a massive difference of a few eV, conceivably comparable to neutrino masses, could account for the matter-antimatter asymmetry ?

[swansont]

Are anti-matter particles ever-so-slightly more massive, than matter particles ? I understand, that our universe contains 7x as many protons, as neutrons, because the former are less massive, and so were 7x more numerous, at the temperature, when baryons became bound into nuclei, i.e. Boltzmann factor [math]e^{-\frac{\Delta E}{k_B T}}[/math]. If the matter-antimatter asymmetry, related to the baryon-to-photon ratio [math]\eta \approx 10^{-10}[/math], arose when the universe was approximately the temperature-equivalent of Weak bosons [math]\approx 100 GeV[/math], then a massive difference of a few eV, conceivably comparable to neutrino masses, could account for the matter-antimatter asymmetry ?

 

Why would [math]e^{-\frac{\Delta E}{k_B T}}[/math] matter for pair production?

 

Anyway, the e-/e+ ratio has been measured at 1±1.3 x 10^-7, and since it's from 1981, there's probably an even better number out there.

P.B. Schwinberg, R.S. Van Dyck Jr., H.G. Dehmelt,1981,Phys.Lett.A,81, 119

 

proton/antiproton to 4 parts in 10^8

http://www.thefreelibrary.com/Protons+and+antiprotons+held+in+the+balance.-a09227949

[Widdekind]

Why would [math]e^{-\frac{\Delta E}{k_B T}}[/math] matter for pair production?

 

I guess I don't understand. If "raw energy" had numerous "mass states" to "choose from", why wouldn't the "raw energy" occupy more, of the lower energy states, per the Boltzmann factor ?

 

By like logic, more leptons would plausibly have been generated, than quarks.

 

What do I not understand ? If matter-antimatter asymmetry does not arise, from their (pair) production by photons, i.e. the EM; then I must look to the Weak & Strong Forces. And, are not both of the latter as matter-antimatter symmetric, as the EM Force ?

 

[math]\gamma \longrightarrow \bar{e}{e}[/math]

 

[math]W^{-} \longrightarrow \bar{\nu}_e{e}[/math]

 

[math]g \longrightarrow \bar{q}{q}[/math]

From whence arises the matter-antimatter asymmetry? Has said asymmetry been "hidden", "deposited" into a plethora of non-interacting anti-neutrinos, "masked" by their prolific "high profile" electron kin ?

 

Speaking of such slight asymmetries, the anti-could, hypothetically, mass more than the proton, by up to "four parts in 100 million", i.e. 40eV. So, it is possible, that anti-matter masses slightly more, e.g. "a neutrino masses worth", than matter ?

Edited January 15, 2012 by Widdekind

[swansont]

I guess I don't understand. If "raw energy" had numerous "mass states" to "choose from", why wouldn't the "raw energy" occupy more, of the lower energy states, per the Boltzmann factor ?

 

But that isn't a factor in pair production. It's not a "choice" between a particle and antiparticle — you get both. Not getting both, or getting an asymmetry in decay, is a matter of CP violation.

[G Anthony]

Why do particle physicists and cosmologists seem to be so very bent on totally ignoring John Wheeler and Hugh Everett? How can they embrace Alan Guth's Inflaton field and particle and at the same time dismiss the ramifications of a fully quantum universe? We are trying to meld quantum mechanics/dynamics and relativity into a GUT or TOE, spending hundreds of millions per year to support scientists, professors and graduate students. But, the consequences of a quantum universe seem to be just swatted away like an angry mosquito. If the universe was once a quantum entity, then it still is. And, if there was an inflaton particle, there was a virtual anti-particle that our universe has not yet met and annihilated. The John Wheeler style quantum interference of the inflaton wave form to give its anti partner may mean that there is a universe full of antimatter almost right beneath our feet. The superposition of states to give the universe that we see only means that we cannot sense the other state or states that may superpose to produce our reality. But quantum mechanics/dynamics demands that they are there. So, there is no paradox here.

But, scientists have always been reluctant to extend quantum to macroscopic scales even though there is a lot of research to find ways to do precisely this and the correspondence principle demands that it should be possible. I guess it would be too disappointing for them to learn that it has already been done - at least 13.72 billion years ago and perhaps a lot more than 27.44 billion years ago. Maybe they fear the day when a GUT or TOE will spell the end of cosmology and particle physics. We may not have to wait another 30 billion years for our parcel of space to loose causal contact with the rest of the cosmos (LOL).

[Widdekind]

Before our ultra-early universe cooled, down to temperatures ~2 GeV, pair-production, of nucleons-with-anti-nucleons, would have kept nucleons & anti-nucleons in relative equilibrium ? I.e. our observed matter-over-anti-matter dominance, only "froze in", after nucleon/anti-nucleons "solidified", at T < 2 GeV ?

 

Meanwhile, electrons/anti-electrons would still have been pair-produced, down to temperatures ~1 MeV, at which time, they would also have "solidified" & "frozen in".

 

Er go, are there not two matter-over-anti-matter asymmetries, the first for baryons ~2 GeV; and the second for leptons ~0.001 GeV ?

 

I'm confused, for several reasons. First, pions would have been produced, prodigiously, down to temperatures ~0.14 GeV. And, pions can inter-convert [math]n^0 \leftrightarrow p^{+}[/math]. So, even if matter baryons, and anti-matter anti-baryons, "froze out", in fixed-or-decaying numbers, back at ~2 GeV; then any surviving baryons / anti-baryons could have kept inter-converting, down to ~1/7 GeV. And, during that epoch (2 GeV --> 1/7 GeV), protons & anti-productions would possibly have interacted more strongly, than neutrons & anti-neutrons.

 

Also, if the observed matter nucleon ratio, of 7p:1n, is attributed to a Boltzmann factor [math]e^{-\frac{\Delta E}{k_B T}} \sim \frac{1}{7}[/math], then [math]\Delta E \approx 1.3 \; MeV \implies k_B T \approx 2.5 \; MeV[/math]. But why would p,n have been able to so "freely" inter-convert, down to such "cold" temperatures, when pion production would plausibly have ceased, back at temperatures nearly a hundred times higher ??

 

And, if pions / anti-pions were produced, prodigiously, down to ~140 MeV; could their interactions, have generated additional nucleons / anti-nucleons ??

 

Vaguely, several temperature regimes would possibly have been identifiable:

 

T > 2 GeV

-- pair-production generates nucleons, anti-nucleons

T > 1/7 GeV

-- pair-production generates pions, anti-pions; nucleons, anti-nucleons freely inter-convert

T > 1/1000 GeV

-- pair-production generates electrons, anti-electrons

How would the "bare" quark / anti-quark masses, ~few MeV, affect these phenomena ?

 

The n:p number ratio is comparable to the nucleon:pion mass ratio, ~1/7, a coincidence; but meaningful, or a fluke ?