Wallflowers become extroverts in a crowd

Sep 28, 2010 by Kandice Carter

While it's long been said that two's company and three's a crowd, that's just how mesons like it. A recent experiment at DOE's Jefferson Lab demonstrates that these subatomic particles engage more with other particles when in a crowd.

One of the simplest ways to study subatomic is to scatter a highly energetic beam of particles off a single . However, the reality is a little messier. Most nuclear physics experiments produce new particles inside nuclei, which contain many protons and neutrons. A nucleus presents far more crowded conditions: new particles are surrounded by the nucleus' protons and neutrons, and their quarks and gluons.

Physicists conducted an experiment to measure how easy or difficult it is for a particle to travel through the crowded conditions of different nuclei, their so-called nuclear transparency. In the experiment, energetic photons were beamed into the of five targets: deuterium, carbon, titanium, iron and lead. Two types of mesons, omega and phi, were produced as the photons smacked into the nucleus. Just like protons and neutrons, omega and phi mesons are built of quarks.

The experimenters found that the more protons and neutrons in the nucleus, the fewer omega and phi mesons made it out. Hence, in terms of nuclear transparency, the nucleus becomes less transparent to mesons as its numbers of protons and neutrons increase.

The new paper featuring the result was published in the September 10 issue of .

Explore further: New insights found in black hole collisions

add to favorites email to friend print save as pdf

Related Stories

Extra large carbon

Feb 09, 2010

An exotic form of carbon has been found to have an extra large nucleus, dwarfing even the nuclei of much heavier elements like copper and zinc, in experiments performed in a particle accelerator in Japan. ...

Physicists plan quark conference

Apr 13, 2005

Physicists from around the world will gather at Madison's Monona Terrace from Wednesday, April 27 - Sunday, May 1, to explore the world of quarks, subatomic particles that represent the frontier of modern particle physics. The mee ...

Recommended for you

New insights found in black hole collisions

Mar 27, 2015

New research provides revelations about the most energetic event in the universe—the merging of two spinning, orbiting black holes into a much larger black hole.

X-rays probe LHC for cause of short circuit

Mar 27, 2015

The LHC has now transitioned from powering tests to the machine checkout phase. This phase involves the full-scale tests of all systems in preparation for beam. Early last Saturday morning, during the ramp-down, ...

Swimming algae offer insights into living fluid dynamics

Mar 27, 2015

None of us would be alive if sperm cells didn't know how to swim, or if the cilia in our lungs couldn't prevent fluid buildup. But we know very little about the dynamics of so-called "living fluids," those ...

Fluctuation X-ray scattering

Mar 26, 2015

In biology, materials science and the energy sciences, structural information provides important insights into the understanding of matter. The link between a structure and its properties can suggest new ...

Hydrodynamics approaches to granular matter

Mar 26, 2015

Sand, rocks, grains, salt or sugar are what physicists call granular media. A better understanding of granular media is important - particularly when mixed with water and air, as it forms the foundations of houses and off-shore ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

Noumenon
1 / 5 (1) Sep 29, 2010
So the greater the number of nuclear components the less transparent the nucleus is; I guess at the quantum level one should never take things as obvious. Wouldn't the components of the nucleus absorb the photon energy; the more components the more degrees of freedom to absorb the beam, so less energy for meason creation, so less are formed to start with? Would this still be considered nuclear transparency?
Noumenon
3 / 5 (2) Sep 30, 2010
No one is reading this because of the title.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.