Observation of Exotic Baryon


Physicists Find Evidence for an Exotic Baryon


Strong evidence for a new five-quark baryon state (known as a pentaquark) has been reported by a team of physicists known as the CLAS Collaboration working at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Virginia. Jefferson Laboratory is operated by the U.S. Department of Energy. The group includes Kenneth Hicks and Daniel Carman from the faculty of the Ohio University Department of Physics and Astronomy, whose research is funded by the National Science Foundation. The CLAS Collaboration acknowledges the lead authors on this work. Kenneth Hicks is the spokesman of the CLAS Approved Analysis for the pentaquark and is also a member of the team of physicists known as the LEPS collaboration in Japan ( Takashi Nakano spokesman) which first announced the discovery.


The following links explain the work that was done and its implications:

Explanation for the general public.

Explanation for the general scientist.

Explanation for physicists .

Scientific paper (submitted to Physical Review Letters) .

The following image is courtesy of the American Institute of Physics:



Press coverage of the pentaquark baryon discovery :

AIP Physics News Update

Scanned images of newspaper articles

MSNBC Science News

links to other web reports,



Other useful background links for the pentaquark :

Los Angeles Times Newspaper: PDF

New York Times Newspaper: PDF

Science Magazine: PDF

Recent review on the status of pentaquarks from theorist H.J. Lipkin : (PDF)

Paper from the SPring-8 collaboration in Japan (T. Nakano et al.) first announcing a pentaquark state at LEPS: (PDF)

Theoretical prediction of the pentaquark from Diakonov, Petrov, and Polyakov : (PDF)

Paper from the ITEP group in Russia with recent evidence for a pentaquark state : (PDF)

CIPANP conference summary where the CLAS pentaquark result was first announced : (PDF)

PowerPoint file of Jefferson Lab proposal (Summer 2003) : (PPT)




Last modified: July 23, 2003
Kenneth Hicks