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Why There’s More Matter Than Antimatter in the Universe

28 Mar , 2008 by

In the first few moments of the Universe, enormous amounts of both matter and antimatter were created, and then moments later combined and annihilated generating the energy that drove the expansion of the Universe. But for some reason, there was an infinitesimal amount more matter than anti matter. Everything that we see today was that tiny fraction of matter that remained.

But why? Why was there more matter than antimatter right after the Big Bang? Researchers from the University of Melbourne think they might have an insight.

Just to give you an idea of the scale of the mystery facing researchers, here’s Associate Professor Martin Sevior of the University of Melborne’s School of Physics:

“Our universe is made up almost completely of matter. While we’re entirely used to this idea, this does not agree with our ideas of how mass and energy interact. According to these theories there should not be enough mass to enable the formation of stars and hence life.”

“In our standard model of particle physics, matter and antimatter are almost identical. Accordingly as they mix in the early universe they annihilate one another leaving very little to form stars and galaxies. The model does not come close to explaining the difference between matter and antimatter we see in the nature. The imbalance is a trillion times bigger than the model predicts.”

If the model predicts that matter and antimatter should have completely annihilated one another, why is there something, and not nothing?

The researchers have been using the KEK particle accelerator in Japan to create special particles called B-mesons. And it’s these particles which might provide the answer.

Mesons are particles which are made up of one quark, and one antiquark. They’re bound together by the strong nuclear force, and orbit one another, like the Earth and the moon. Because of quantum mechanics, the quark and antiquark can only orbit each other in very specific ways depending on the mass of the particles.

A B-meson is a particularly heavy particle, with more than 5 times the mass of a proton, due almost entirely to the mass of the B-quark. And it’s these B-mesons which require the most powerful particle accelerators to generate them.

In the KEK accelerator, the researchers were able to create both regular matter B-mesons and anti-B-mesons, and watch how they decayed.

“We looked at how the B-mesons decay as opposed to how the anti-B-mesons decay. What we find is that there are small differences in these processes. While most of our measurements confirm predictions of the Standard Model of Particle Physics, this new result appears to be in disagreement.”

In the first few moments of the Universe, the anti-B-mesons might have decayed differently than their regular matter counterparts. By the time all the annihilations were complete, there was still enough matter left over to give us all the stars, planets and galaxies we see today.

Original Source: University of Melbourne News Release


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LLDIAZ
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LLDIAZ
March 28, 2008 12:23 PM

can we see anti matter?
and if you can’t is that something astronauts in the future will have to worry about.

Kevin
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Kevin
March 28, 2008 1:18 PM

We can “see” anti matter as in it leaves tracks on detectors just like matter. We can capture antimatter and have used it in accelerators to create higher energy collision. There was even an article on this sight that talked about antimatter being create by natural processes.

I don’t think that astronauts, in our usual definition of the word have much to worry about. Once we leave the cozy confines of our solar system or galaxy, that might be a different story

Ethan Siegel
Guest
March 28, 2008 2:20 PM

The difference between B-mesons and anti-B-mesons is known as “CP violation”, and it means that they decay into the same things, but in different ratios. This can create more baryons than anti-baryons, but not *enough* to explain the amount of baryons we have in the Universe today. As far as we know, there needs to be new physics to create the observed amount of matter that we have.

Timber
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Timber
March 28, 2008 4:11 PM
This may be a long way off the point of Fraser’s article, but the first paragragh raised the issue in my mind. He says the annihilation generated the energy that drove the expansion (inflation?) of the universe. The April issue of Astronomy has an article on the shape of the universe that is suggesting that the inflation (expansion?) of the universe occured prior to the annihilation and the generation of the energy followed. Am I just confusing the same view? And this is really off the subject, but that same article when talking about strings and Calabi-Yau manifolds says that strings were initially regarded as having diameters in the order of Planck scale (10 to the -33 centimeters)… Read more »
stringsleavemehangin
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stringsleavemehangin
March 28, 2008 6:04 PM

well if 10,000 trillion = 10^16
then that much larger than 10^-33 cm is 10^-17 cm, which is only a couple orders of magnitude smaller than the theoretical diameter of electrons.

Timber
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Timber
March 28, 2008 6:22 PM

Thank You

greg your last name
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greg your last name
March 28, 2008 6:57 PM

saturday night, 10pm. i am reading universetoday. i seriously love this stuff! fascinating!

Hai
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Hai
March 28, 2008 7:52 PM

I heard that when u do a “PET” scan in the hospital, ur body actually interacted with anti-matter(s) (we are the anti-matter?), is that true?.

PHWilson
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PHWilson
March 29, 2008 4:37 AM

Wikipedia’s entry for PET states: The positron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1, a spin of 1/2, and the same mass as an electron. When a low-energy positron collides with a low-energy electron, annihilation occurs, resulting in the production of two gamma ray photons (see electron-positron annihilation).

Indeed, PET is all about real antimatter. Mapping of the brain functions sounds much more benign than – “We’re gonna watch antimatter annihilations in your brain today”, so the general population still envisions the existence of antimatter as Star Trek pie in the sky, unfortunately.

Thameron
Member
Thameron
March 29, 2008 9:47 AM

Anti-matter is rather ubiquitous. Several radioactive isotopes decay by positron emission

carbon-11, potassium-40, nitrogen-13, oxygen-15, fluorine-18, and iodine-121.

Each of us has some potassium-40 (half life of 1.248 billion years) in our bones so chances are you are making a bit of anti-matter right now.

Bob
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Bob
March 29, 2008 10:08 AM

Why doesn’t this article mention CP-violation?

Nate
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Nate
March 29, 2008 3:43 PM

this whole issue is solved not by physics and theoretical laws, but the answers are found in the Holy Bible. I quote: “In the begging God created the heavens and the earth.” The origin of all matter and anti-matter are explained in the first sentence of the Bible. All things exists because God said a couple words. No science can prove it, but so far science can’t prove the origin of the universe either! Both are accepted by faith.

ALOKMOHAN
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ALOKMOHAN
March 29, 2008 10:01 PM

Nate,there is no n further need to read hard as God seems to have solved everything.

Astrofiend
Member
Astrofiend
March 30, 2008 5:04 AM

Nate Says:
March 29th, 2008 at 3:43 pm

“…this whole issue is solved not by physics and theoretical laws, but the answers are found in the Holy Bible. ”

Nate, God thinks you’re a moron.

“God has no place within these walls, just like facts have no place in organised Religion!” – The Simpsons.

God
Guest
God
March 30, 2008 5:24 PM
Sorry, I was busy talking with billions of people in private while creating matter, energy and intervening with some dice games and curing a few sick children who happened to be under medical treatment. Only a few that is. Gosh, it’s really a busy schedule. Astrofriend is right. I do think Nate is a moron. I am even questioning my own capabilities regarding my intelligent design. I must have made a huge mistake somewhere in the blueprints. The only thing I provide is proof. Everywhere in creation. But these lunatics insist that everything is a matter of faith. Well, I suggest that these enlightened people jump off a high building to test my faith. Do it by thousands.… Read more »
Nate
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Nate
March 30, 2008 7:20 PM
The only reason that this world has any problems (medical or even death) is because of US! None of you who read these articles can say that you NEVER did anything wrong; if you do then you are lying and that’s something wrong in it self. Do you think that this world in all of it’s complexity’s (example: cells, ecosystem’s, the correct position of the earth from the sun etc.) do you honestly believe, leaving all prejudices behind, that the universe was a huge accident!?! that our top scientists can’t figure out even with billions of dollars in there pockets a year !?! I love science, and I love to learn about the things of God’s universe. God… Read more »
stringsleavemehangin
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stringsleavemehangin
March 30, 2008 8:40 PM
first off…Nate, why are you commenting on this page? Did god tell you to come try and convert all us non-believers by leaving blanket faith statements on forums. Now to respond to you saying that since things are so perfect in the universe for us to be here means that there must be a god who designed it all. There are equivalent scientific theories about that. Please go read about the Anthropic Principle, which states that any universe humans observe will naturally be one that supports life and has all of its physical constants perfectly tuned for the observers (us) to exist. So if the universe, multiverse, or cosmos in general is basically infinite or really really big.… Read more »
Pankaj
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Pankaj
March 30, 2008 11:50 PM

I do believe in God but why should that stop me from trying to learn about this universe … Has HE said anywhere that be ignorant !!! ….

Few centuries back so many diseases were there we had no cure for …. and we simply had one explanation that God wants to punish us for our sins…
but now because we have medicines so God no longer punishes us smile .. may be HE is happy that we have more knowledge now

Cheers
Guest
Cheers
March 31, 2008 7:18 AM

OK Fraser, there you go again. Another fine article which concludes with the definitive statement to prove your story that something “might have decayed differently.”

Peter
Member
Peter
March 31, 2008 7:48 AM
Nate, not surprising that you restated your premise. Religion has been saying the same tired things over and over again for nearly 2000 years because there’s only one book to get your info out of, (if you ignore the other texts that got booted from the “Official, and Certified” edition) Do you mind if we, in our ignorance, and lack of faith, try to figure out how “God” did it? It’s an interesting question and we’re just curious, like we were when we developed the polio vaccine. P.S. No one is talking about being perfect but you. Frankly, it is perfectly clear that we were put here to sin, as there are so many rules and even more… Read more »
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