ISSN:0031-9228    

DOI:10.1063/1.2806653

出版商:AIP    

年代:1997

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.881611

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The study of very unstable nuclei is exciting interest in many labs throughout the world. When the Nuclear Science Advisory Committee (NSAC) published its long‐range plan a year ago, it noted that, until recently, nuclear physicists had primarily studied nuclei near stability and those rich in protons, although these nuclei represent less than a tenth of the nuclear systems expected to exist. Tightly bound nuclei are at the bottom of the so‐called valley of stability (See the figure on this page). “By adding either protons or neutrons one moves outward towards the ridges of the valley of stability, finally reaching the drip lines where the binding of nucleons [in the nucleus] ends,” NSAC wrote. With beams of short‐lived radioactive nuclei becoming available, NSAC declared, “The scientific opportunities made available by world‐class radioactive beams are extremely compelling and merit very high priority.”

ISSN:0031-9228    

DOI:10.1063/1.881612

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Thanks to external funding, antimater research at CERN will continue. CERN's antiproton complex, which in the fall of 1995 was the first to produce antihydrogen, was closed at the end of last year to free up money for the Large Hadron Collider. Now, however, one part of this complex, the antiproton collector, is to be upgraded and rechristened the “antiproton decelerator,” scheduled to begin operating in early 1999.

ISSN:0031-9228    

DOI:10.1063/1.881615

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The top quark os a most remarkable Particle even for a quark. A single “top,” as we will casually call it here, weighs 175 GeV, about as much as an atom of gold. But unlike the gold atom, which can be disassembled into 79 protons, 79 electrons and 118 neutrons, top seems to be indivisible. With an experimental resolution approaching10−16 cm,we have not discerned any structure. Top's predicted lifetime of about 0.4 yoctoseconds(0.4×10−24 s)makes it by far the most ephemeral of the six varieties of quarks. The compensation for this exceedingly brief life is a measure of freedom: Top decays before it suffers the confining influence of the strong interactions. In spite of its fleeting existence, the top quark nonetheless helps shape the character of the everyday world.

ISSN:0031-9228    

DOI:10.1063/1.881890

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The purpose of this article is to describe some themes in theoretical physics that developed independently for many years, in some cases for decades, and then converged rather suddenly beginning around 1994–95. The convergence produced an upheaval sometimes called “the second superstring revolution.” It is as significant in its own way as “the first superstring revolution,” the period around 1984–85 when the potential of string theory to give a unified description of natural law was first widely appreciated.

ISSN:0031-9228    

DOI:10.1063/1.881616

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Our atmosphere is a great natural laboratory. Atmospheric scientists can use this laboratory to look for physical phenomena, to teach physical ideas and to develop practical technologies.

ISSN:0031-9228    

DOI:10.1063/1.881891

出版商:AIP    

年代:1997

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.881957

出版商:AIP    

年代:1997

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.881604

出版商:AIP    

年代:1997

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2806654

出版商:AIP    

年代:1997

数据来源: AIP