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Behold the pentaquark Physicists have discovered a new class of subatomic particle that will provide unexpected insights into the fundamental building blocks of matter. Theory predicted where the particle should emerge.

Le pentaquark, nouveau venu dans la matière La découverte des physiciens japonais et américains accroît encore le mystère des quarks, particules élémentaires de l'univers de Cyrille Vanlerberghe, Physical Review Letters3 Juillet 2003

New Matter May Have Been Found Physicists detect what could be a five-quark particle. The data are said to be convincing, but the interpretation remains a question. By K.C. Cole, Los Angeles TimesJuly 1, 2003 It's not every day that physicists discover nature singing an entirely unknown tune, but that's what physicists in the U.S. and Japan appeared to have detected in two sets of quite different experiments on opposite sides of the world.

Physicists discover particle with five quarks By Peter Rodgers, Physics WebJuly 1, 2003 After 30 years of searching physicists have finally found evidence for particles containing five quarks. Most particles are either mesons, which contain a quark and an antiquark, or baryons, which comprise three quarks or three antiquarks. Now nuclear physicists in Japan and the US have discovered a particle that contains two up quarks, two down quarks and a strange antiquark.

Timeline: Discovering quarks and quarkstars 1960s: theoretical physicists, trying to account for the ever-growing number of subatomic particles observed in experiments, consider the possibility that protons and neutrons are composed of smaller units of matter.

Scientists Report Discovery of a New Kind of Subatomic Particle By Richard Monastersky, Chronicle of Higher EducationJuly 1, 2003 In a discovery that has physicists relearning how to count, three teams around the globe report that they have identified a subatomic particle consisting of five quarks -- a number never before seen in the zoo of fundamental particles.

Subatomic breakthrough announced by physicists Discovery of 5-quark particle could aid research into matter By Alexandra Witze, Dallas Morning NewsJuly 1, 2003 Physicists announced Monday that they have evidence for a never-before-seen subatomic particle — one composed of five quarks.

U.S. Focus: Particle Party Just Got Bigger New state of matter proved Experiments confirm subatomic stuff is real By A.J. Hostetler, Richmond Times-DispatchJuly 1, 2003 "Welcome to the club." In the cocktail party of known matter, physicists at the Jefferson Lab say revelers must make elbow room for a new state of matter, the pentaquark.

ЯПОНСКИЕ ФИЗИКИ СДЕЛАЛИ ОТКРЫТИЕ ИСКЛЮЧИТЕЛЬНОЙ ВАЖНОСТИ ИЗВЕСТИЯ 3 июля 2003 Японские физики сделали исключительной важности открытие: в ходе бомбардировки высокоэнергетическими фотонами атомов углерода, им удалось получить новый тип субатомных частиц - состоящих из пяти кварков. Пока было известно только о частицах, содержащих два или три кварка (такие, как протоны, например). Частиц с четырьмя, пятью или шестью кварками до сих пор никому не удавалось обнаружить.

A Five-Quark State Has Been Discovered by Phil Schewe, James Riordon, and Ben Stein, Physics News UpdateJune 30, 2003

Elusive pentaquark captured By Alan Boyle, MSNBC NewsJune 30, 2003 Four decades ago, physicists proposed that subatomic particles were made up of different combinations of even smaller units known as quarks — a word that was lifted from James Joyce's difficult-to-comprehend novel "Finnegans Wake."

Japanese physicists' 'pentaquark' hints at answers to makeup of matter By Dan Vergano, USA TODAYJune 30, 2003 Physicists have discovered a new class of subatomic particles, offering unexpected insights into the building blocks of matter. The discovery involves tiny particles called "quarks," the bricks and mortar of protons and neutrons in the atomic nucleus.

It's a Ball. No, It's a Pretzel. Must Be a Proton. By Kenneth Chang, The New York TimesMay 6, 2003 Ask four physicists a seemingly simple question — Is a proton round? — and these might be their responses: Yes. No. The first two answers are both correct. What do you mean by "round"?

Atomic Buffet We used to think of protons as billiard balls, but now there's a smorgasbord of possible shapes to choose between, from peanuts to sausages and chicken drumsticks. Charles Choi explains: Charles Choi, New ScientistMay 3, 2003

Terahertz radiation coming through a window from the free-electron laser is reflected by a mirror onto the detector array of a pyroelectric camera to produce this false-color, real-time video image. (Jefferson Lab)

Former ORO acting manager selected for Jefferson Lab The Oak Ridger OnlineApril 17, 2003 The U.S. Department of Energy has recently selected James A. Turi as the new site manager for the Thomas Jefferson National Accelerator Facility in Newport News, Va.

Holey Grail A new experiment confirms that protons take a variety of different shapes. The EconomistApril 12, 2003

Jefferson Lab in the News Physicist's work changes modern view of the proton By Philip Walzer, The Virginian-PilotApril 6, 2003 NORFOLK — Her father wanted her to follow his path as a Sanskrit teacher.

Far-infrared sources diversify by Sunny Bains, Laser Focus WorldJanuary 2003