ISSN:0031-9228    

DOI:10.1063/1.3068863

出版商:AIP    

年代:1975

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3068865

出版商:AIP    

年代:1975

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3068868

出版商:AIP    

年代:1975

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3068869

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

High‐energy experimentalists are starting to paint a more complete, although still sketchy, picture of the new particles at 3.1 and 3.7 GeV that were discovered by surprise last November (seePHYSICS TODAY, January, page 17). Results so far are consistent with the early expectations that both particles are vector particles. They have been photoproduced, and the high‐energy resonance has been seen to decay into the lower one. Finally, these two particles appear to stand alone, as searches for other narrow resonances have so far yielded nothing except a broad peak at 4.1 GeV. Such was the picture presented by experimentalists from several institutions at the Annual APS Meeting in Anaheim, California from 29 January to 1 February. While the new results fit into some of the proposed theoretical schemes better than into others, they do not mesh completely with any of them. In a possibly related development, a weakly interacting particle carrying a new quantum number has been suggested by recent neutrino experiments. (See box on page 24.)

ISSN:0031-9228    

DOI:10.1063/1.3068871

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Does positronium have an analogy in the nucleon–antinucleon system? The existence of such narrow bound states is a possible explanation for results of a recent experiment that seem to contradict predictions of charge independence. Specifically, a team from Syracuse University, New York and from the Nuclear Research Center Demokritos in Athens, Greece found that in pionic annihilations at rest of antiprotons on deuterium, the resulting charged pions carried away less energy than is expected if the strong interaction forces are independent of charge. The Syracuse–Athens team then gathered evidence that the “missing” energy is taken away by an excess number of gamma rays; that is, more gamma rays than should be produced by decay of the neutral pions into two gammas. The experimenters feel that these extra gammas represent electromagnetic transitions between narrow nucleon–antinucleon resonances or bound states, which they have named “cosmion.” If their interpretation is correct then perhaps such narrow nucleon–antinucleon resonances or bound states are connected to the newly discovered J or &psgr; particles at 3.1 and 3.7 GeV; such is the suggestion of Alfred Goldhaber and Maurice Goldhaber. Another interesting feature of such possible states is that their characteristic gamma rays could identify regions of the universe where antimatter (if it exists) meets matter.

ISSN:0031-9228    

DOI:10.1063/1.3068872

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

A pulsar that is slowing down much less rapidly than any other known pulsar may have some interesting implications for current theories of pulsar formation and perhaps even for theories of expansion of the universe. David Richards, John Rankin and Gustave Zeissig studied the pulsar, JP 1953, as one of 13 in a continuing program of precise pulse timing at the Arecibo Observatory in Puerto Rico. A surprising result of the study, they comment inNatureis that for JP 1953,dP/dt,the change in its 0.4 sec period with time, is only about0.003±0.007×10−15seconds per second. The previously known smallest value for any pulsar had been0.15×10−15,and a typical value exceeds10−15.

ISSN:0031-9228    

DOI:10.1063/1.3068873

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

Interest in neutrino physics has surged up recently, partly because the “little neutral ones” are being groomed for the job (for which they alone are qualified) of probing the interiors of stars. Among elementary particles the neutrino is unique. This is because—as far as we know—it alone interacts with other particles only through the Fermi, or weak, interaction. In this article we will discuss how recent experiments, with new accelerators and detectors, such as the ones at CERN and Fermi Lab, have shed new light on some of the fundamental questions regarding the weak interactions. We will review the recent discoveries of neutral weak currents that conserve strangeness, parity violation and point‐like neutrino collisions, as well as some of the implications of these experiments to particle theory.

ISSN:0031-9228    

DOI:10.1063/1.3068874

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

A pendulum can be stopped by a single impulse of the right magnitude, delivered at the proper time; started again, its phase will have changed. A biological oscillation, although it is a vastly more complicated phenomenon, can likewise be arrested by a single stimulus of a definite strength delivered at the proper time. This remarkable fact emerges from experiments I have conducted on two biological clocks, in organisms in the plant and animal kingdoms. The most interesting potential applications are, of course, those that involve the internal clocks of Man.

ISSN:0031-9228    

DOI:10.1063/1.3068875

出版商:AIP    

年代:1975

数据来源: AIP

摘要:

The time has come for technical people in industry to take the lead in establishing international programs in energy research and development. To show why we believe this, we will have to explain why we think international ventures in the energy field will turn out to be best handled by industry‐to‐industry contacts, rather than through some kind of government‐to‐government dialog, and also why we think it is time that industrial scientists, rather than purely business‐minded executives, played leading roles. Close links with cooperating government agencies will of course still be appropriate and necessary, but initiatives should now come from industrial scientists.

ISSN:0031-9228    

DOI:10.1063/1.3068876

出版商:AIP    

年代:1975

数据来源: AIP