---

PHYSICS MEETING IN LONG BEACH
 

---

Please do not report on the results mentioned in this press release until the day the respective paper is given.

For more information contact Phillip Schewe, 301-209-3092, pschewe@aip.org, or Ben Stein, 301-209-3091, bstein@aip.org, at the American Institute of Physics, or Randy Atkins at the American Physical Society, 301-209-3238, atkins@aps.org.

College Park, MD, March 14, 2000 ----- The second of the two big general meetings held annually by the American Physical Society (APS), its Spring meeting, will take place in Long Beach, California April 29-May 2, 2000. (The earlier meeting, the March meeting in Minneapolis, has itself not yet occurred; it takes place March 20-24.).

The Spring Meeting, which complements the March Meeting in its subject matter, encompasses particle physics, nuclear physics, astrophysics, and a host of sessions on high-precision research, plasma physics, and social issues relating to physics.

WEBSITE AND ABSTRACTS
The official meeting website, http://www.aps.org/meet/APR00/ offers a quick way to view hotel and travel information and all the abstracts. Complimentary press registration will allow science writers to attend all scientific sessions. If you wish to come, please fill out and return the form at the end of this release. The meeting pressroom will be located in the Long Beach Convention Center, room 201B. A "virtual pressroom," containing lay-language versions of selected meeting papers, will be available starting in mid-April. Press conferences will take place in room 201A. Pressroom hours: Sat-Mon (April 29-May 1) 8 AM to 5 PM and Tues, 8 AM to noon. Pressroom phone numbers 562-499-7780 and 81, fax 562-499-7784. Breakfast and lunch food will be available in the pressroom Sat-Mon.

HIGHLIGHTS OF THE MEETING
PHYSICS CONSTANTS ARE A-CHANGIN'
The mass of an electron, Avogadro's number, the strength of the gravitational force--the recommended values for these and other fundamental constants have just changed for the first time since 1986. Recently, an international body known as the Committee on Data for Science and Technology (CODATA) got together to compile new values (available on the web at http://physics.nist.gov/constants). Peter Mohr of NIST will discuss the most striking adjustments to the fundamental constants. (W10.03, Tuesday) Among the highlights: the Rydberg constant (the quantity which prescribes the wavelengths of an atom's spectrum) is known 100 times more accurately than in 1986, in large part because of dramatic improvements in measuring the frequency of light (and this will be detailed by Ted Haensch of the Max Planck Institute in talk N1.02.) On the other hand, the recommended value for G, the gravitational constant, is 10 times less precise than before. How can additional measurements lead to a less-precise value? Mainly because of a highly respected but utterly perplexing experiment in Germany during the 1990s which yielded a G measurement that was radically different from the previously accepted value. The most recent experiments (described in session P11, Monday morning) seem to push G back toward its traditional value, but no one can figure out what (if anything) went wrong during the German experiment.

QUANTUM CYCLOTRON
In efforts that may lead to the most precise determination yet of the magnetic moment of the electron (the strength of the tiny "bar magnet" lurking within every electron), Gerald Gabrielse of Harvard and his colleagues have realized for the first time a "quantum cyclotron": a single electron, in its lowest energy state traveling in a circular "cyclotron" orbit about a magnetic field inside a closed container or "cavity." The electron is so cold (70 millikelvin, the lowest temperature yet recorded for a charged elementary particle) that it exhibits effects peculiar to the quantum world. The researchers can monitor the electron for weeks, without destroying its quantum state, observing its every quantum jump between energy states. By watching the electron's reaction as photons are injected into the cavity, the researchers can record the photon frequency at which the electron jumps most rapidly to a higher-energy state. Measuring the magnitude of this "resonance frequency" allows the researchers to determine the electron's magnetic moment Gabrielse will show examples of quantum jumps and will discuss progress towards this measurement, which would lead to the most precise way (by an order of magnitude) for determining the fine structure constant, the quantity that describes the inherent strength of the electromagnetic interaction that holds all atoms and molecules together (Paper C4.04, Saturday).

SPIES LIKE US
Since the spring of 1999, when the New York Times first reported an allegation of a Chinese spy at Los Alamos National Laboratory, attention has focused powerfully and sometimes with heated disagreement on the possible threat to national security of foreign-born scientists employed at the national weapons laboratories. At session C2 a panel of scientists will discuss various aspects of the issue and suggest possible guidelines for setting U.S. policy on this sensitive and important issue. Jerry Wilhelmy of Los Alamos will address his alarm at what he perceives as a "growing sense of xenophobia" and the foreign national involvement at Los Alamos National Lab [see www.fellows.lanl.gov]. Cheuk-Yin Wong, who chairs the Overseas Chinese Physics Association in addition to his work as a research scientist at Oak Ridge National Laboratory, will review the history of the Chinese- American science community and its contributions to the advancement of science and national defense in the U.S.

Nor is China alone under the cloud of suspicion. Following the nuclear tests in 1998 by India and Pakistan, the Department of Energy banned collaborative efforts with scientists from those countries, despite a long history of collaboration. The ban has only recently been rescinded. Rajendran Raja, an Indian-born scientist at Fermilab, will review recent developments -- including the denial of authorization in 1999 for eight DOE physicists to travel to India for a high-energy physics conference -- and assess the implications of such restrictions on scientific freedom. A related talk will be given by John McTague, chair of the Committee on Balancing Scientific Openness and National Security of the National Academies, during a Sunday morning session on science and technology policy.

TRIUMPH OF 20th CENTURY ASTROPHYSICS
(1) How do we know there was a Big Bang? Charles Linweaver of the University of New South Wales (Australia) will recount the evidence in favor of a Big Bang origin. According to Linweaver, "Most people do not believe, do not like, or do not understand this scientific version of Genesis." (2) What do we know (and don't know) about the Sun's influence on the Earth? Judith Lean of the Naval Research Lab will run down a list if important ponderables: space weather, solar variability, climate change, ozone depletion. (3) How do we know the Sun runs on nuclear energy? Roger Ulrich of UCLA proffers as clues the apparent age of the Sun, the strength of gravity, neutrinos streaming to Earth from the Sun's interior, and the observed acoustic ringing of the Sun's orb. (4) What is the universe made of and how do we know it? Michael Turner of the University of Chicago offers reasons for believing a receipt consisting of 5% ordinary matter, 30% dark matter, and 65 % dark energy, the energy associated with the mechanism which seems to be speeding up the expansion of the universe. (5) How do we know there are black holes in quasars? Mitchell Begleman of the University of Colorado looks at the data. (Session P8)

TRIUMPH AND FALL OF 2nd CENTURY ASTROPHYSICS
Session Q22 looks at the longtime acceptance of Greek astrophysics and how it came to be questioned. James Evans of the University of Puget Sound shows how Ptolemy cleared up a clutter of confused ideas about the world and crystallized a unified picture of the heavens, the chief point being that the Sun and planets circulated around the Earth. Distinguished science historian Owen Gingerich of Harvard-Smithsonian will discuss the aesthetic considerations behind Copernicus' 16th-century reform of Ptolemy's model, a revision which put the Sun at the center of things but which retained the impractically perfect ideal of circular planetary orbits so loved by the Greeks. George Saliba of Columbia will describe the Islamic astrophysics that came between Ptolemy and Copernicus.

FLY'S EYE
Cosmic rays are the rare particles that come from deep space and rain down upon our atmosphere, where they trigger showers of particles recorded in detectors lofted upwards beneath balloons or spread out across the desert floor. The biggest puzzle in cosmic-ray physics is the origin of the most-potent rays, those with energies above 10^20 electron volts. If the progenitor particles had come from distances more than about 50 Mpc (mega-parsec; 1 parsec is a bit more than 3 light years) away, their energy should have been sapped by cosmic microwaves. And yet there is no obvious candidate source nearby to have produced such high energies. The leading opinion is that the 10^20-eV events come from some "astrophysically dark" source, perhaps the decay of some superheavy particles left over from the inflation period in the early universe. Scientists from the new high-resolution version of the Fly's Eye detector in Utah will report seven new deluxe events from the high energy frontier. (Session C16)

SAILING ON THE SOLAR WIND
In the late 1950s, Eugene Parker predicted the existence of the solar wind, the continuous stream of charged particles (mainly hydrogen and helium ions) from the Sun. The contributor of most of the particles in Earth's magnetosphere, the solar wind has at least one major unanswered question associated with it: exactly how the Sun accelerates it from the solar environment. Thomas Holzer of the High Altitude Laboratory/National Center for Atmospheric Research will discuss the latest insights into this issue. Presenting recent data from the SOHO spacecraft, Steven Cranmer of the Harvard-Smithsonian Center for Astrophysics will review solar observations bearing on solar wind acceleration. We are most familiar with the solar winds of our Sun, but other stars produce solar winds that can differ radically. Stan Owocki of the University of Delaware will discuss these winds, which can sometimes reach flow speeds 1% of the speed of light, and lose mass a billion times faster than the Sun's solar wind. Barry Mauk of Johns Hopkins will discuss how the Earth's magnetosphere differs from those of other planets. Paulett C. Liewer of the Jet Propulsion Laboratory will discuss the Interstellar Probe, a NASA spacecraft that will be propelled by a solar sail. In the short time of 15 years, the craft will travel to a new frontier: interstellar space, more than 200 astronomical units from the Sun (where 1 AU is the distance between the Sun and the Earth). This is far beyond the heliopause, the end of the solar system, which is roughly 125 AU from the Sun. (Sunday, Session H14)

PLENARY TALKS
Four plenary sessions, held between Saturday and Monday, will feature some of the hottest topics in physics--described by researchers who are intimately involved with them. Robert Austin of Princeton will discuss how nanotechnology and microfabrication tools are being applied to the study of biological molecules such as DNA. Paul Butler of UC-Berkeley will provide an overview of planets outside our solar system. Deborah Jin of the University of Colorado/NIST will report on the bizarre properties of an ultracold gas made of fermions, particles that belong to the same class as electrons. Kenneth Gregorich of LBL will describe the observation of superheavy elements at LBL's new gas-filled separator at the 88-Inch Cyclotron Saul Perlmutter of UC-Berkeley will explain how observations of supernova, made by him and his colleagues, led to the surprising conclusion that the universe is accelerating. Janet Conrad of Columbia will review the many recent results involving the search for neutrino oscillations, the idea that the superabundant particles known as neutrinos transform from one "flavor" to another. Patricia Heller of the University of Minnesota will discuss science standards in the schools. (Sessions A1 G1, N1, R1.)

NEXT-GENERATION PRECISION MEASUREMENTS
In 1998, researchers at NIST announced the most precise determination yet of the Planck constant, the number which quantifies the bundle-like nature of matter and energy. David B. Newell of NIST will discuss plans to make Planck constant measurements 10 times more precise than those available already. In separate work employing a Penning trap, a device that uses electric and magnetic fields to trap charged particles, Robert Van Dyck of the University of Washington will discuss recent experiments which may reduce the uncertainty of the atomic mass of oxygen by a factor of five. David Shiner of the University of North Texas will discuss measurements of fine structure in the helium atom's spectrum, which provide an alternate route towards calculating the fine-structure constant and can lead to deeper insights into the complex interactions involving several nuclear particles such as those that form a helium nucleus.Klaus Jungmann of the University of Heidelberg will review recent measurements of the anomalous magnetic moment of the muon (a heavy cousin of the electron), and will explain how these measurements constitute a search for new and yet unknown interactions beyond the Standard Model. (Session C4)

BOILING THE VACUUM
Hot papers from the realm of particle and nuclear physics: Claudio Pellegrini of UCLA will discuss an experiment aimed at using intense x-ray beams for producing electron-positron pairs, a process, called "boiling the vacuum" (paper V19.4). "Beamstrahlung" is a kind of radiation emitted by particles in future (500 GeV) electron-positron colliders. Unlike the traditional "bremsstrahlung" (German for "braking radiation") or synchrotron radiation emitted by particles undergoing acceleration, beamstrahlung would be much more intense, and would represent a considerable loss of the beam-particle energy, in the high-charge-density environment at the point of collision. Ming Xie of LBL reports that there might be a way to suppress this unwanted form of radiation using quantum mechanics (V19.2). Allesandro Ruggiero of Brookhaven will review progress toward creating "crystalline beams," an arrangement in which ions circulating in a storage ring can be cooled in such a way that the ions fall into strings, zig-zag patterns, and helices, even as they move at high speeds around the ring (H21.5).

ARMS CONTROL
Arms control issues have reached a critical turning point, particularly with regard to ballistic missiles, according to speakers at a Monday afternoon session on the subject. John Cornwall of the UCLA, will speak on the proposed national missile defense (NMD) program, intended to counter accidental Russian or Chinese launches of intercontinental nuclear-armed missiles, or similar launches by rogue nations. He believes that any national capable of building or purchasing such systems can also build or purchase effective countermeasures to NMD, and thus suggests a better strategy would be to provide technical assistance to such countries to improve their launch control systems. Cornwall will be joined by Roy Pettis of the State Department, who will report on progress and status of the 1998 Presidential Initiative on Shared Early Warning to reduce the risk of ballistic missile launches. (Session Q12)

THE ORIGIN OF COSMIC MAGNETIC FIELDS
Scientists are coming to the realization that they have another cosmological mystery at hand: the evolution of magnetic fields at cosmological scales such as galaxies. Understanding such magnetic fields could provide significant contributions towards understanding the formation of galaxies and other large-scale structures in our universe. Scientists originally thought that turbulence could amplify a magnetic field from a small seed in a galaxy over time, creating large-scale order from chaos, but recent studies have suggested that turbulent noise might itself be amplified and overwhelm the buildup of a large-scale galactic magnetic field. Presenting an overview of what is known about the history of the universe's magnetic fields, Angela Olinto of the University of Chicago will discuss how ultra-high energy cosmic rays, which are most likely affected by intergalactic magnetic fields on their journey, can provide one of the best probes of the magnetic fields that exist between galaxies. Making radio and x-ray observations of galactic clusters, Philipp Kronberg of the University of Toronto and his colleagues have found unexpectedly strong magnetic fields in the relatively rarefied regions between galaxies in a cluster--and have determined that these fields are, amazingly, at least as strong as those within the much denser disk of our Milky Way. Amitava Bhattacharjee of the University of Iowa says that the "dynamo effect" (which explains how the movement of electric current generates magnetic fields) works well in describing Earth's magnetic field, but becomes more problematic and complex when applied to explaining a galaxy's magnetic field, and says that additional mechanisms such as fast "magnetic reconnection" (which annihilate small-scale magnetic fields) need to be explored. (Session B7, Saturday).

MECHANICAL UNIVERSE
Finding ways to communicate science effectively outside the classroom is also the focus of a Monday morning session featuring David Goodstein, who will summarize lessons learned from his involvement in "The Mechanical Universe," a 52-part television series. Completed in 1987, the series is designed to teach introductory physics at the university level. It is still widely used in American colleges and high schools and has been translated into 13 languages. David Crippens of KCET-TV Education Enterprises in Los Angeles, will provide examples of work the public television station has done to increase and enhance science literacy. Other lectures in the session will feature the popular Discovery Science Center, which opened in December 1998 and has had more than 290,000 visitors since, and an overview of the Aquarium of the Pacific's education program, which opened in June 1998 and had over 1.8 million visitors in its first year. ( P13)

GREEN ENERGY
Today's cars and trucks are the largest source of air pollution in most urban areas in the U.S., accounting for 25% of the nation's carbon emissions more than most countries emit from all sources combined. But James Mark of the Union of Concerned Scientists believes that a host of emerging technical improvements could help alleviate this problem, most notably with alternative electric vehicles powered by batteries, small hybrid engines, or fuel cells. His fellow speakers at a Monday morning session include Princeton University's Joan Ogden, who will report on the potential for the development of a zero-emission transportation system using fuel cells powered by hydrogen. Offering an alternative is Dan Cohn of MIT, who believes plasmatron electric discharge technology can enable onboard hydrogen production to improve the environmental quality of automobiles, trucks and buses. Richard Post, a researcher at Livermore will report on the development of new types of magnetic ball bearings that should enable the construction a new magnetically levitated (maglev) train system. Thomas Surek of the National Renewable Energy Laboratory will round out the session with a status report on photovoltaics, a semiconductor-based technology that directly converts Sunlight into electricity. Photovoltaics have become a billion-dollar industry worldwide, with market initiatives for grid-connected photovoltaics in residential and commercial buildings expected to fuel even more future growth. [Session P12]

WOMEN ASTRONOMERS
For more than a century women have played a key role in astronomy, making major discoveries that have advanced the field, a tradition which continues today. A Tuesday morning session sponsored by the APS Committee on the Status of Women in Physics seeks to highlight some of these stellar woman astronomers. They include Wiliamina Fleming, Antonia Maury and Annie J. Cannon, who helped classify more than 11,000 stars using a systematic classification scheme co-developed by Fleming in the latter part of the 19th century; Cecelia Payne, whose analysis and interpretation of stellar spectra in the Harvard collection in the 1920s yielded a fundamentally new understanding of the composition of the universe; and Beatrice Tinsley, who contributed enormously to establishing the formalisms for studying the chemical evolution of galactic systems with a seminal article in 1980. [Session V8]

STRANGER THAN FICTION
Camille Minichino, formerly a researcher with Lawrence Livermore National Lab, and Gregory Benford, a professor of physics at the University of Irvine, both moonlight as authors of mystery and science fiction novels. Benford, an astrophysicist and plasma researcher, has won numerous prestigious awards for his fiction, which ranges from alternate-history scenarios in 20th-century Earth to the plight of human colonists who find themselves tyrannized by artificial life forms in the center of our galaxy in the distant future. Minichino, in her whodunit "The Hydrogen Murders" and its sequels (which are named after the successive elements in the Periodic Table), employs in her novels scientists who work in realistic lab settings. On Sunday afternoon, the authors will explain why such formats offer a prime opportunity to introduce the general reader to real-world physicists: "ones who don't want to take over the world, don't leave the house with two different types of socks on, and aren't social misfits." It is a means of reaching the public that is often overlooked by those who seek to popularize science, despite the fact that the general public draws its views of science from fictional formats. The session will be followed by a reception to meet the authors and a book signing. (Session K12)

Jennifer Ouellette of APS News contributed to the preparation of this press release.