Bottom quarks reveal something of their identity

July 07, 2005

Dutch researcher Bram Wijngaarden investigated how bottom quarks are created during collisions between protons and antiprotons. Wijngaarden's measurements have contributed to a better understanding of the theory, and can be used to explain why the production of these quarks during such collisions is higher than had originally been expected.

Bram Wijngaarden investigated the creation of bottom quarks using the D zero experiment of the particle accelerator at the Fermi lab in Chicago, United States. In this Tevatron particle accelerator, protons and antiprotons collide with each other. Bottom quarks are created as a result of the strong nuclear force that arises during these collisions. In the 1990s measurements with the Tevatron particle accelerator and with the Hera particle accelerator in Hamburg revealed that the production of bottom quarks was higher than had been theoretically predicted. Since then theoretical physicists have done a lot of work to explain the difference. Wijngaarden's measurements must reveal whether the theory provides a good description of the reality.

Bottom quarks

Bottom quarks are created during high-energy collisions between particles. The bottom quark is one of six quarks. Together with the top quark it is one of the heaviest quarks. These quarks are only found under extreme circumstances, such as during collisions between particles. After the collision the bottom quarks decay into other particles. Measuring devices detect the electrical signals left behind by the particles. Signals from the decay products of the bottom quarks can be distinguished from the other particles released because bottom quarks are heavier and on average breakdown slightly less quickly.

By measuring the angle between two bottom quarks from the same collision, Wijngaarden could study the strong nuclear force directly. This angle was measured as the angle between the avalanches from the decay products of the bottom quarks. In the first-order approach, the theory predicts that the two bottom quarks always move apart from each other at an angle of 180 degrees. Wijngaarden showed that in a number of cases the angle is much smaller. The second-order approach predicts that the angle is much smaller in a number of cases but the average size of the angle measured by the researcher differed from the result obtained using this approach. The strong nuclear force can be tested more accurately with new measurements made with the help of methods developed by Wijngaarden.
-end-
Bram Wijngaarden's research was funded by NWO.

For further information please contact:

Dr Bram Wijngaarden (Institute of Mathematics, Astrophysics and Particle Physics, Radboud University Nijmegen)
t: 31-243-652-099
dwijngaa@hef.ru.nl
The doctoral thesis was defended on 22 June 2005
Supervisor Prof. S.J. (Sijbrand) de Jong

Netherlands Organization for Scientific Research

Related Quarks Articles from Brightsurf:

Observation of four-charm-quark structure
Hadrons are composed of quarks, a type of fundamental particle, bound by the strong interaction.

New research deepens mystery of particle generation in proton collisions
Researchers have shown that in polarized proton-proton collisions, the neutral pions in the very forward area of collisions -- where direct interactions involving quarks and gluons are not applicable -- still have a large degree of left-right asymmetry.

Scientists shed light on mystery of dark matter
Nuclear physicists at the University of York are putting forward a new candidate for dark matter -- a particle they recently discovered called the d-star hexaquark.

Exploring strangeness and the primordial Universe
Within quark-gluon plasma, strange quarks are readily produced through collisions between gluons.

Deuteron-like heavy dibaryons -- a step towards finding exotic nuclei
Using supercomputer, TIFR's physicists have predicted the existence of deuteron-like exotic nuclei for the first time as well as provided their masses precisely.

FSU physics researchers break new ground, explore unknown energy regions
Florida State University physicists are using photon-proton collisions to capture particles in an unexplored energy region, yielding new insights into the matter that binds parts of the nucleus together.

A novel tool to probe fundamental matter
The origin of matter remains a complex and open question.

CEBAF turns on the charm
The world's most advanced particle accelerator for investigating the quark structure of the atom's nucleus has just charmed physicists with a new capability.

Physicists reveal why matter dominates universe
Physicists in the College of Arts and Sciences at Syracuse University have confirmed that matter and antimatter decay differently for elementary particles containing charmed quarks.

Physicists solve 35-year-old mystery about quarks
Physicists from Tel Aviv University, the Massachusetts Institute of Technology and the Thomas Jefferson National Accelerator Facility now know why quarks, the building blocks of the universe, move more slowly inside atomic nuclei, solving a 35-year-old-mystery.

Read More: Quarks News and Quarks Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.