Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Indiana University scientists first to detect rare nuclear fusion violating charge symmetry


This symmetry violation makes hydrogen possible, a requirement for life

Scientists at the Indiana University Cyclotron Facility in Bloomington have made the first unambiguous detection of a rare process, the fusion of two nuclei of heavy hydrogen to form a nucleus of helium and an uncharged pion. The pion is one of the subatomic particles responsible for the strong force that holds every nucleus together. The achievement will be announced Saturday (April 5) at the meeting of the American Physical Society in Philadelphia.

"Scientists have searched for this rare fusion process since the 1950s," said IU physicist Edward Stephenson, the leader of the research team. "The process would not happen at all if nature did not allow a small violation of what is known as charge symmetry. If this symmetry violation had happened to be in the other direction, hydrogen would not have survived after the Big Bang, and the universe would not have the hydrogen fuel that keeps stars shining, including our sun, making human life possible. Sometimes large consequences hang on delicate balances in nature."

One effect of this charge symmetry violation is that the neutron is slightly heavier than its charged partner, the proton. As a result, isolated neutrons decay into protons in about 10 minutes. "If the charge symmetry violation had been in the other direction instead, and if the proton had been heavier than the neutron by the same slight amount, protons would have decayed into neutrons and hydrogen could not have survived," Stephenson explained.

The rate at which the rare fusion process occurs is expected to be a key piece of information in finding the cause for this violation of charge symmetry, he said. Theorists have proposed that the violation originates with quarks, the small particles that are found inside protons and neutrons.

"The rate of the process will tell scientists how much of the violation comes from the fact that quarks carry small electrical charges, and how much comes from the difference in mass between the two types of quarks found inside neutrons and protons," Stephenson said.

The IU team used the electron-cooled storage ring at the cyclotron laboratory to focus a beam of heavy hydrogen onto a target of the same material. The high precision of the beam allowed them to use just enough energy to make the uncharged pion without producing unwanted heavier particles. Sensitive detectors tracked the helium nuclei and captured the two photons or particles of light that are produced when the pion decays.

The team worked around the clock for two months, seeing at most only five of the rare events per day, Stephenson said. However, the several dozen events that they collected will be enough to allow scientists to test their theories about the violation of charge symmtery.

Their research was supported by a grant from the National Science Foundation.

For more information, contact Stephenson at 812-855-5469 or

Hal Kibbey | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>