!Hecho en Mexico!
Kaon experiment commissions detector components from Mexican university

by Gary Ruderman

In his 28 years at Fermilab, physicist Herman White has both witnessed and helped encourage the globalization of science.

“The focus today is on international cooperation,” White said, “especially in high-energy physics. We are a world society.”

With this extended focus, every part of the world takes on increasing importance—and offers increasing opportunities.

White recently worked as both kaon researcher and diplomat in helping complete an agreement with Universidad Autonoma de San Luis Potosi (UASLP), in Central Mexico north of Mexico City, to build part of the detector for Fermilab’s Charged Kaons at the Main Injector (CKM) experiment. While Mexican researchers have a longstanding presence at Fermilab, the agreement marks the first time that a Mexican institution has been responsible for building part of a new experiment.

“This is an embryonic collaboration between the U.S., Mexico and Russia,” White explained. “It’s an opportunity to bring people together from all around the world.”

The choice of UASLP grew from already-established collegial associations. This international outreach centers around two Fermilab high-energy alumni: Jürgen Engelfried and Antonio Morelos Pineda. Engelfried was a postdoctoral candidate from the University of Heidelberg studying charmed particles at Fermilab. Engelfried went on to CERN and then to the university in San Luis Potosi. Morelos Pineda was a graduate student at Fermilab from San Luis Potosi who studied under the Mexican theorist Augusto Garcia.

Engelfried and Morelos Pineda are also collaborators on the SELEX experiment, which has announced indications of baryons containing two charm quarks, a combination never seen before experimentally (see the story on Page 2).

“The commitment of the scientists really drives many choices for specific contributions to the project,” White explained. “This is mostly the case for San Luis Potosi in that our collaborators there have the expertise for significantly contributing to the design of the detector, including producing the mirrors. It’s the usual practice to go to those with a history of expertise, someone you know.”

Fermilab has a history of outreach toward Mexico and other countries in Latin America, sparked by director emeritus and Nobel laureate Leon Lederman. While serving as Fermilab director in the late 1970s Lederman called for more cooperation with Latin America.

“With a GDP of hundreds of billions of dollars there is no logical reason why Latin America could not develop to the equal of Europe,” Lederman said recently. “So why not give them a hand?”

U.S. Rep. Rush Holt (D-NJ), former assistant director of Princeton Plasma Physics Laboratory, is a proponent of scientific collaboration beyond the usual connections with Japan and Europe. He applauded the Fermilab accord with San Luis Potosi.

“When you consider that much of scientific research is for the sake of knowledge, in other words for cultural reasons,” said Holt, “it’s almost incumbent on the American researchers to include …some international breadth to the research.”

Holt added that while the United Nations leads a great deal of the international scientific collaboration, much more of the cooperation happens “through some collegial or individual contacts.”

At Fermilab, connections with developing nations are growing.

“Now we’re focusing on countries like Bangladesh and Vietnam, where physicists are in short supply,” explained physicist Peter Cooper, who signed the accord with San Luis Potosi as CKM spokesperson. “We are the United Nations of physics.”

Under the memorandum of understanding, San Luis Potosi will design and build the mirror array for the Ring Imaging Cerenkov counter of CKM.

Cerenkov light is produced by particles traveling faster than the speed of light in water. The light is focused by a mirror array into the Ring Imaging Cerenkov counter. Measuring the angle of the light’s emissions in a cone around its trajectory allows researchers to measure the particle’s velocity, trajectory and energy.

The CKM experiment—which hopes to begin taking data in about 2006—looks at rare kaon decays that, at their foundation, provide another view of the properties of symmetry or asymmetry between particles and antiparticles. The CKM experiment is designed to maximize the efficiency of observing and measuring very rare kaon decays.

In the case of kaon decays, rare means quite rare, indeed. The first measurement of this particular rare kaon decay required a 15-year search at Brookhaven National Laboratory. The second was made in 2001. The CKM experiment at Fermilab anticipates measuring 100 events in a two-year period, which White explained would provide a precise measurement of the decays and another test of the Standard Model of fundamental particles and forces.

The agreement between Fermilab and UASLP might also extend its reach beyond the production of the mirror array.

“Possibly, from a university perspective,” White said, “participating in a large international research project will attract students to a unique technical area, and supporting that participation is just a good idea.”

Which could, in turn, spur further funding from the Mexican university. Adding perspective to the San Luis Potosi collaboration, White said the scientists who come through Fermilab from other countries are the “seed corn” for future experiments—and for future connections.

“Since our motivation is academic,” White said, “we’ve reached out ever since this facility was built. As a society, reaching out is what we must do.”