[-empyre-] musings from the edge of scientific knowledge
Akram.Khan at brunel.ac.uk
Mon Oct 31 09:44:23 EST 2011
Sondra what a wonderful insight! Here are a few more detail remarks....
What’s the matter with anti-matter? The mystery of CP violation:
The study of CP violation addresses a very fundamental question: are the laws of physics the same for matter and anti-matter, or are matter and anti-matter intrinsically different? The answer to this very question may hold the key to solving the mystery of the matter-dominated Universe.
According to the Big Bang theory, equal amounts of matter and anti-matter were created at the beginning of times. When matter and anti-matter get in contact, they annihilate into pure energy, producing photons and nothing else. The relic of this primordial annihilation is the Cosmic Microwave Background, the 2.7 Kelvin radiation that fills the entire Universe. But not all of the matter annihilated into photons: about one out of every billion quarks survived and originated the Universe as we know it today. How could some matter survive the primordial annihilation? Where did the corresponding anti-matter go? Why did matter survive over the anti-matter?
In 1967 the Russian physicist Andrei Sakharov proposed a solution to this puzzle. Sakharov’s explanation required the violation of what was considered a fundamental symmetry of nature: the so-called CP symmetry.
Is Nature CP symmetric?
CP is a discrete symmetry of nature given by the product of two components: the charge conjugation (C) and the parity (P). Charge conjugation transforms a particle into the corresponding anti-particle: if we apply C to an electron, we will obtain a positron. In other words, charge conjugation maps matter into anti-matter. Parity is the transformation that inverts the space coordinates: if we apply P to an electron moving with a velocity from left to right, the electron will flip the direction and end up moving with a velocity , from right to left. In other words, parity produces the mirror image of reality.
Therefore, when we apply a CP transformation to an electron moving with a velocity from left to right, we will obtain a positron moving with a velocity , from right to left. This means that CP gives us the mirror image of the anti-matter. Naively, we would expect that the anti-matter to behave just as the matter, with the exception of swapping “right” and “left”: after all, we would be very surprised if our image in the mirror would behave differently from us! But is this always the case? In other words, is CP a good symmetry of Nature?
Both electromagnetic and strong interactions are symmetric under C and P, therefore they must also be symmetric under the product CP. This is not necessarily the case for the weak force, which maximally violates both C and P symmetries, as demonstrated by Chien-Shiung Wu in 1957 in the study of the decays of Cobalt-60. Until 1964, however, CP symmetry was naively assumed to hold in weak interactions as well. One reason for this assumption was the CPT theorem, which states that all quantum field theories must be symmetric under a combined transformation of C, P and T (time reversal). CP violation therefore implies violation of the time-reversal symmetry, which at the time was beyond imagination.
The discovery of CP violation came therefore completely unexpected in 1964, when Val Fitch, Jim Cronin, and collaborators observed this phenomenon for the first time in the study of the decays of neutral kaons, particles formed by a strange quark and a down anti-quark. The observed effect was small, one part in a thousand, but was extremely important because it proved that matter and anti-matter are intrinsically different. For this discovery Fitch and Cronin were awarded the Nobel Prize in 1980.
It took us almost ten years to explain this phenomenon in the context of the Standard Model of Particle Physics. In 1973, two Japanese physicists, Makoto Kobayashi and Toshihide Maskawa, successfully explained CP violation by postulating the existence a third family of quarks, for which there was no experimental evidence at the time.
From: empyre-bounces at lists.cofa.unsw.edu.au [empyre-bounces at lists.cofa.unsw.edu.au] On Behalf Of Sondra Fraleigh [eastwest at q.com]
Sent: 26 October 2011 20:29
Subject: Re: [-empyre-] musings from the edge of scientific knowledge
Thanks you so much Akram for this thought provoking post. I have been convinced for years that physics has so much to offer artists, and I have liked reading about the intersection of art and physics, wherever I find those physicists who can make their very technical world available to readers at large, and to perspectives on spirituality and the human also.
I'm saving your post because I have learned so much from you here, and now I want to choreograph a work called. "What's the Matter with Antimatter"? I am so fascinated with the idea you present- that through asymmetry in the early universe, the laws of nature were biased toward matter, which is a explanation of how we are here as a very symphony of matter, or I might want to say, a symphony that continues to matter. I am also reminded that "matter" is the basis for our word "mother." I wrote about the mattering of ourselves through the maternal, material, matter, materia, of the mother in Dancing Identity: Metaphysics in Motion.
I get a bit out of the box though, because I turn toward the great mother mythological concepts of the divine feminine, and the many names of the divine mother in various cultures. Interesting how one can morph from physics to mythology. Artists have this freedom, I think. Maybe physicists do also. I don't know. You scientists probably have to keep your jobs, and not get to crazy.
On Oct 26, 2011, at 2:44 AM, Akram Khan wrote:
It is not with a little trepidation that I make my first posting; during the past few weeks I have found these thought-provoking discussions, at times, floating over my scientific head.
As a particle physicist my professional career has been all about a constant iterative process of formulating fundamental questions so that they are most amenable to being solved: Of what is the universe made? How did it all begin? What’ll be its ultimate fate?
In my opinion here are some of the most critical questions which if answered will lead to a complete transformation of our understanding of what we are and of our place in the universe.
1) If the Universe began with the Big Bang – what happened to the antimatter that ought to have been there? .i.e. what is the matter with antimatter? Through an asymmetry in the early universe the laws of nature were biased towards matter, which is why we are here at all but why?
2) What are the ultimate constituents of matter? We start off with rainbows, molecules, atoms, electrons, neutrons and protons. The protons and neutrons as made of “quarks”, two different types. So, the smallest experimentally observed entities of matter are: electrons; muons, taus , neutrinos and the six quarks [plus their antimatter partners]. This begs the question, is there another deeper, more fundamental level of reality not yet seen? And the answer is maybe! Instead of thinking about particles being the DNA or fundamental building blocks of our universe, might these not be oscillating fundamental strings, where each harmonic of the string corresponds to a particular known particle; with each of us being a very symphony of such notes.
3) What is the nature of mass? And it is here that the hypothetical Higgs particle steps into the limelight.
4) Do we live in a multidimensional universe of which we only see the four dimensions of spacetime?
5) Is ours but one of many worlds or ‘membranes’ floating through the ‘Bulk’?
6) What is the basic nature of time?
There are many more questions still but I fear this contribution is in imminent danger of morphing beyond manageable bounds...and the intention was but to provoke some dialogue. Please feel free to choose any topic that you’d like us to start exploring...... further thoughts I will post anon...
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