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Inspiring Ignorance: Perspectives of Particle- and Astrophysics at the 60th Lindau Nobel Laureate Meeting

22.06.2010 - (idw) Kuratorium für die Tagungen der Nobelpreisträger in Lindau e.V.

The fabric of the world were living in was a controversial topic even in 1953 at the first meeting of Nobel Laureates in Physics in Lindau. At the 60th Meeting of Nobel Laureates, which will begin on Sunday, it will again play a key role. Since physicists have realized that only 4% of the universe consists of known ingredients, while 96% is made of dark matter and dark energy, the basic construction of this fabric is more mysterious than ever before. Now, the huge particle accelerator, the Large Hadron Collider (LHC) at the European Nuclear Research Centre in Geneva, Switzerland offers the opportunity to shed light on this darkness. Six Nobel Laureates who have made significant contributions to particle physics and cosmology during the last decades will discuss their expectations of the experiments at the LHC at a symposium on Tuesday, June 29. The Standard Model of particle physics describes the rules by which twelve elementary particles, four forces, and twelve field particles that transmit these forces, work in concert. It has been developed since the mid-1970s, experimentally proven time and again, and could soon be merged with the Big Bang model of cosmology. The latter rests on Einsteins theory of general relativity and includes the assumption that our world originates from the explosion of a tiny dot of highly concentrated energy an assumption experimentally endorsed by measurements of cosmic background radiation in 1965. Despite its elegance, the Standard Model has gaps; for example, it cannot explain how elementary particles receive their mass or why there are three families of elementary particles when only one seems to be required. Also, gravity cannot yet be integrated into the theoretical connection between elementary particles and the cosmos. Thats why David Gross (Nobel Prize in Physics 2002) in his 2008 Lindau lecture The Large Hadron Collider and the Super World, which is available as a video in the online library of the Nobel Laureates Meetings, emphasized: The most important product of knowledge like the development of the Standard Model is ignorance; by which I meaninformed ignorance, good questions that can be probed and answered by observation, by experiment and by theory.

Detection of new Elementary Particles in the Large Hadron Collider

Both laureates and young scientists expect good answers to these questions from experiments in the Large Hadron Collider (LHC) in Geneva, as it is a wonderful instrument to create particles of which you didnt know the existence according to Martinus Veltman (Nobel Prize in Physics 1999) in his 2008 lecture The Development of Particle Physics. After being accelerated to a speed close to that of light in a subterranean ring with a circumference of 27 kilometres, protons inside the LHC collide with an overall energy of 14.000 billion electron volts. This is comparable to the energy within the universe one trillionth of a second (10-12 sec) after the Big Bang. According to Einsteins equation, E = mc², a part of this collision energy turns into matter. Thus, elementary particles which are characteristic for the very origin of our universe could be detected inside the LHC. This includes the not yet detected Higgs particle which exists theoretically to explain how elementary particles gain their mass and electromagnetically neutral particles, the so-called WIMPS (weakly interacting massive particles), which are suspected to form dark matter.

Almost 80 years ago, astrophysicists first proposed the existence of invisible matter. They had observed that some galaxies rotate faster around their centre than the laws of gravitation and their visible mass allow. On average, their stars have only 10% of the mass that would be necessary to keep them in orbit and prevent them from flying apart. Applying the method of gravitational lensing, the existence of dark matter, which surrounds the stars of a galaxy like a scaffold, could be verified in the 1970s because it bends space and distorts light that reaches the earth. Dark matter accounts for 23% of the entire mass of the universe.

A dynamic Interplay in Vacuum

Dark energy was discovered in 1998. It is a repulsive force, counteracting gravity and accelerating the expansion of the universe. Nobody knows whats hidden behind this energy that makes up nearly 75% of our universe. There are speculations, however, that it could be related to the energy density of the vacuum of space. While matter mutually attracts each other via gravity, parts of the empty space obviously repel each other because the vacuum contains energy. This energy of Nothingness is one of the biggest current mysteries of physics, as David Gross with good humour mentioned in his 2008 lecture: Our job is to understand nothing, if we understand the vacuum, the rest is trivial.

Werner Heisenberg, who earned his Nobel Prize in Physics in 1932 at the age of 31, explained the origin of the force in the vacuum in his 1968 Lindau lecture Kosmologische Probleme in der heutigen Atomphysik (Cosmological Problems in Modern Atomic Physics) in 1968. He referred to a discovery of his English colleague Paul Dirac (Nobel Prize in Physics 1933), himself a ten-time participant in the Lindau Meetings. Dirac had discovered that the transformation of energy into matter always leads to the generation of anti-matter. For example, a particle like an electron is always formed together with a positron. Conversely, when a particle and an anti-particle collide, they annihilate each other and turn into energy. Even pure Nothing, Heisenberg said, could therefore virtually transform into a number of particle pairs and become a composed system or rather a dynamic problem. Hence, inside the vacuum, a continuous interchange between matter and energy, the so-called vacuum fluctuations, would prevail; matter turns into energy, and energy into matter, at almost infinite speed.

According to the knowledge of current physics, the energy of the Big Bang also created matter and anti-matter. In fact, both would have destroyed each other immediately if a slight asymmetry in favour of matter had not occurred, thus rendering the existence of our world. I guess that one can now anticipate where the bridge between elementary physics and cosmology must be built, Heisenberg explained, predicting the merger between these two disciplines of physics. At that time, Heisenberg saw this idea as a dream of the future, yet he did not hesitate to speculate because in Lindau you occasionally have a licence for such dreams.

Symposium on Tuesday, June 29, beginning at 14:30 CET including a Live-Broadcast from the Control Room of the LHC in Geneva - http://www.lindau-nobel.org

"What will CERN teach us About the Dark Energy and Dark Matter of the Universe?" with Nobel Laureates David Gross (P 2004), John C. Mather (P 2006), Gerardus t Hooft (P 1999), Carlo Rubbia (P 1984), George F. Smoot (P 2006) and Martinus J.G. Veltman (P 1999)

At the 60th Nobel Laureates Meeting there will be in addition to the symposium - eight lectures and discussions on topics related to elementary particles and cosmology:

John C. Mather (Nobel Prize in Physics 2006): The History of the Universe, from the Beginning to the Ultimate End

George F. Smoot (Nobel Prize in Physics 2006): Mapping the Universe and its History
Robert W. Wilson (Nobel Prize in Physics 1978): The Discovery of Cosmic Background Radiation and its Role in Cosmology
Carlo Rubbia (Nobel Prize in Physics 1984): Underground Physics: Neutrino and Dark Matter
David Gross (Nobel Prize in Physics 2004): Frontiers of Physics
Gerardus t Hooft (Nobel Prize in Physics 1999): The Big Challenges
Martinus Veltman (Nobel Prize in Physics 1999): The Development of Particle Physics
James W. Cronin (Nobel Prize in Physics 1980): Cosmic Rays: The Most Energetic Particles in the Universe

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