Featured Research

from universities, journals, and other organizations

Answer From 'Dusty Shelf' Aids Quest To See Matter As It Was Just After Big Bang

Date:
March 28, 2005
Source:
University Of Washington
Summary:
Scientists trying to recreate conditions that existed just a few millionths of a second after the big bang that started the universe have run into a mysterious problem -- some of the reactions they are getting don't mesh with what they thought they were supposed to see.

Scientists trying to recreate conditions that existed just a few millionths of a second after the big bang that started the universe have run into a mysterious problem -- some of the reactions they are getting don't mesh with what they thought they were supposed to see.

Now, two University of Washington physicists have dusted off a quantum mechanics technique usually associated with low-energy physics and applied it to results from experiments at Brookhaven National Laboratory on New York's Long Island that produce high-energy collisions between gold nuclei. The result is data much more in line with what theorists expected from the experiments, said John Cramer, a UW physics professor. That means physicists at Brookhaven probably have actually succeeded in creating quark-gluon plasma, a state of matter that has not existed since a microsecond after the big bang that began the universe.

As it turns out, the model the physicists were using was missing some pieces, say Cramer and Gerald Miller, also a UW physics professor, whose findings will be published this month in Physical Review Letters, a journal of the American Physical Society.

"We think we've solved the puzzle by identifying important phenomena that were left out of the model," Cramer said.

Since 2000, scientists have been using the Relativistic Heavy Ion Collider at Brookhaven to collide gold nuclei with each other at nearly the speed of light. They are trying to get subatomic particles called quarks and gluons to separate from the nuclei and form a superheated quark-gluon plasma, 40 billion times hotter than room temperature.

Physicists used a technique called Hanbury Brown-Twiss Interferometry, originally used by astronomers to measure the size of stars, to learn the size and duration of a fireball produced in the collision of two gold nuclei. The technique focuses on momentum differences between pairs of pions, the particles produced in the fireball.

Before the collider experiment began, scientists expected a quark-gluon plasma to fuel a large and long-lasting fireball. Instead, the interferometry data showed a fireball similar in size and duration to those seen at much lower energies. Researchers also expected to see pions pushed out of the plasma gradually, but instead they seem to explode out all at once.

"We expected to bring the nuclear liquid to a boil and produce a steam of quark-gluon plasma," Cramer said. "Instead, the boiler seems to be blowing up in our faces."

While other evidence suggested that the collider experiment had created a quark-gluon plasma, the interferometry data pointed away from that possibility. To solve the puzzle, Cramer and Miller used a phenomenon called chiral symmetry restoration, which predicts that subatomic particles will change in mass and size depending on their environment -- in a hot, dense plasma as opposed to a vacuum, for instance.

By adding that process to the model, they found that pions in the plasma have to expend a large amount of energy to escape, as if they were stuck in a deep hole and had to climb out. That is because chiral symmetry gives pions a low mass when they are inside the plasma but a much higher mass once outside. The scientists also allowed for some pions to disappear completely, to transform into some other type of particle as they emerge from the plasma.

The result reconciles all the evidence from the collider experiments, supporting the possibility that a quark-gluon plasma actually has been created.

"We have taken a quantum mechanics technique, called the nuclear optical model, from an old and dusty shelf and applied it to puzzling new physics results," Miller said. "It's really a scientific detective story."

The work, supported by U.S. Department of Energy grants, adds to the general understanding of what happened in the first microseconds after the big bang, he said, "and what we bring to bear is a better microscope, the microscope of quantum mechanics."

Cramer noted that adding chiral symmetry restoration to the picture achieved results very close to what computer models told scientists to expect, and did so without forcing the experimental data to fit preconceived standards.

"A microsecond after the big bang, there was a state of matter that no one was able to investigate until very recently," he said. "We are still learning, but our understanding is growing."


Story Source:

The above story is based on materials provided by University Of Washington. Note: Materials may be edited for content and length.


Cite This Page:

University Of Washington. "Answer From 'Dusty Shelf' Aids Quest To See Matter As It Was Just After Big Bang." ScienceDaily. ScienceDaily, 28 March 2005. <www.sciencedaily.com/releases/2005/03/050325150830.htm>.
University Of Washington. (2005, March 28). Answer From 'Dusty Shelf' Aids Quest To See Matter As It Was Just After Big Bang. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2005/03/050325150830.htm
University Of Washington. "Answer From 'Dusty Shelf' Aids Quest To See Matter As It Was Just After Big Bang." ScienceDaily. www.sciencedaily.com/releases/2005/03/050325150830.htm (accessed April 23, 2014).

Share This



More Space & Time News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nuclear-Level Asteroids Might Be More Common Than We Realize

Nuclear-Level Asteroids Might Be More Common Than We Realize

Newsy (Apr. 23, 2014) The B612 Foundation says asteroids strike Earth much more often than previously thought, and are hoping to build an early warning system. Video provided by Newsy
Powered by NewsLook.com
NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Nasa Gives You An Excuse to Post a Selfie on Earth Day

Nasa Gives You An Excuse to Post a Selfie on Earth Day

TheStreet (Apr. 22, 2014) NASA is inviting all social media users to take a selfie of themselves alongside nature and to post it to Twitter, Facebook, Flickr, Instagram, or Google Plus with the hashtag #globalselfie. NASA's goal is to crowd-source a collection of snapshots of the earth, ground-up, that will be used to create one "unique mosaic of the Blue Marble." This image will be available to all in May. Since this is probably one of the few times posting a selfie to Twitter won't be embarrassing, we suggest you give it a go for a good cause. Video provided by TheStreet
Powered by NewsLook.com
SpaceX's Dragon Spacecraft Captured by International Space Station

SpaceX's Dragon Spacecraft Captured by International Space Station

Reuters - US Online Video (Apr. 20, 2014) SpaceX's unmanned Dragon spacecraft makes a scheduled Easter Sunday rendezvous with the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins