A joint Fermilab/SLAC publication

Key to origin of universe could be neutrinos and Project X

02/13/09

You shouldn't be here.  Not just reading this blog, but anywhere.

You shouldn't exist. Period.

Moments after the big bang, equal amounts of matter and antimatter floated through the universe and when particles of each collided, they annihilated each other, leaving nothing but free floating energy in their paths.

Suddenly something changed, allowing for more matter than antimatter. The little extra bit that escaped annihilation clumped together and over time planets...and eventually you...formed.

But billions of years later no one knows exactly how that happened.

"That's the puzzle," said Boris Kayser, a particle physics theorist with Fermi National Accelerator Laboratory in Batavia, Illinois. "You would have expected an empty universe. Funny. It is not empty. How did that happen?"

Yet, some scientists say they have the key in a new machine called Project X to unlock the mystery of the origin of the universe, and you.

Kayser and fellow physicists Craig Dukes, of the University of Virginia; and Gregory Dubois-Felsmann, of the SLAC National Accelerator Laboratory in California, told a crowd at the American Association for the Advancement of Science in Chicago Friday about the newest research front in particle physics--the intensity frontier--and the newest tool to reach it--Project X, a proposed proton accelerator. The talks focused on the study of rare decays, B factories, and the possible key to the universe: neutrinos.

Neutrinos as the switch that caused matter-antimatter symmetry

The idea is that neutrinos were one of the only subatomic particles abundant enough just after the big bang to have the ability to affect the symmetry of matter and antimatter to the extent that allowed the formation of the universe as it looks now. If the neutrino had interacted differently with matter and antimatter, it could have been the particle that led to the domination of matter over antimatter.

But that would have been a very massive neutrino, one that no longer exists today and is impossible to recreate in today's machines. Even the Large Hadron Collider, the largest science experiment ever built and to be the world's most energetic particle accelerator, won't produce energies high enough to replicate the large mass of a heavy neutrino, one billion times heavier than a proton.

So physicists need a new machine, one that can create large numbers of the lighter cousin of this neutrino, which they believe behaves similarly, to infer how neutrinos just after the big bang would have behaved.

The machine to do that is the proposed Project X, which would shoot a beam of neutrinos 1300 km from Fermilab to an underground detector in the Homestake mine's DUSEL research center in South Dakota. It would be the longest neutrino beam in existence.

"The physics reach of this facility would be quite impressive indeed," Kayser said. "You could see the difference in these (matter/antimatter) processes."

How Project X works

Project X would replace the 35-year-old injection complex at Fermilab, providing an intense source of protons to sustain a program of discovery in neutrino science and precision physics during the next two decades.

More than 78 institutions have shown interest in the science made possible by Project X and another 25 institutions have shown interest in the accelerator design needed to push into the intensity frontier.

The high-intensity proton beam would use an 8 GeV superconducting Linac, paired with Fermilab's existing, but modified, Recycler and Main Injector to generate more than 2 MW of beam power in the energy range of 60 to 120 GeV at the same time as a second beam line of 650 kW at 8 GeV.

Project X will support industrialization of superconducting radio-frequency cavities and cryomodules, as well as create a system test for many In ternational Linear Collider components. Eventually, if and when the ILC is built, Project X could feed a damping ring in the Tevatron tunnel to debug some key components of the ILC before installation at depth, advancing the physics timeline for the ILC.

Project X also would allow for an upgrade supporting a future neutrino factory or a muon collider by doubling the repetition rate and increasing the linac pulse length, creating a beam power of about 4 MW at 8 GeV.

The proposed proton facility would marry a superconducting 8 GeV linac with existing elements of Fermilab’s accelerator complex. Charged hydrogen ions accelerated through the 8 GeV linac would enter the Recycler, where electrons would be stripped off and protons stored. Protons from the Recycler would then enter the Main Injector. In the Main Injector, protons would be accelerated for use in very long baseline neutrino oscillation experiments, such a NOvA and DUSEL. In addition 8 GeV protons from the Recycler could support kaon- and muon-based precision experiments, which could run simultaneously.

What it could do

Project X would provide a new way into the world of neutrinos and precision physics unattainable by the Large Hadron Collider.

It would tackle these fundamental questions with three prongs of experiments at energy levels the Large Hadron Collider can not match:

  • Create an intense neutrino beam to shoot to a detector at DUSEL, the world's deepest laboratory in the Homestake mine in South Dakota.
  • Create kaon- and muon-based precision experiments, potentially including a muon-to-electron conversion experiment, which would probe the physics of unification of forces and matter, and rare kaon decay experiments, which could detect new physics beyond the reach of the LHC.
  • Allow for an upgrade to a neutrino factory or muon collider, aimed at higher energies than proposed for the next-generation linear collider, the ILC.

What next

The project could break ground as early as 2013. In November 2008, a multi-institutional, global collaboration based at Fermilab was officially formed for the R&D phase of the project. Collaborators hope to have the project's scope, cost estimate, and work schedule ready by mid-2009, setting the stage for a possible end of 2009 Critical Decision-0 designation, the first step in the US Department of Energy approval process.

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