Printer Friendly

Aging and decay of beauty.

In the gallant whimsy of physicists, when beauty decays, charm may sometimes remain. Don't reach for the Oil of Olay, however; in this context "beauty" and "charm" are "flavors" of quarks. Flavor is the property that makes one kind of quark differ from another. There are six flavors of quarks, and out of various combinations of them, nearly all the many subatomic particles are supposed to be built. Theory says that a beauty quark should decay into a charm quark. According to the July/August CERN COURIER, a recent experiment at the CERN laboratory in Geneva marks the first time such a decay has been directly observed.

In the event, an energetic pi meson entered a silicon detector, striking an atomic nucleus and producing a negatively charged beauty particle (B.sup.-) and a neutral one (B.sup.0). The B.sup.- traveled 437 micrometers and then decayed into a neutral charm particle and a negative mu meson. The B.sup.0 traveled 4,430 micrometers and decayed into a negative charm particle plus an unspecified positive particle. The event is clean and comprehensive, in that all points where the Bs and the charms were produced fall within the detector. Physicists don't always have that kind of luck.

From the lengths of the trajectories of the B particles, the lifetime of negative beauty comes to 0.8 X 10.sup.-13 second, and that of neutral beauty to 5 X 10.sup.-13 second--fleeting, but sic transit gloria mundi [so passes away the glory of the world]. For physicists the important point is that these numbers are slightly less than those calculated for beauty lifetimes from earlier indirect evidence of beauty decays. That is a good thing, as the longer lifetimes had led some physicists to fear that their "standard model" of particle physics, which explains most things very neatly, might need some amendment.
COPYRIGHT 1985 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1985, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:quark classification
Publication:Science News
Date:Aug 3, 1985
Previous Article:Diamonds in nature; a recently rediscovered recipe for synthesizing diamonds at low pressure may actually work.
Next Article:... And the 'mother-blaming' problem.

Related Articles
Quark-gluon plasma.
Searching for strange matter: the quest extends from neutron stars to monstrous isotopes and compact energy sources.
Building matter from a dozen blocks.
Putting limits on the top quark.
In search of the elusive top quark.
Pushing quarks to the limit.
Quark droplets envisioned in neutron stars.
Extra data bolster top quark discovery.
Beyond the top: now that physicists have found the top quark, what's next?
Starting from square one: the intricate behaviors of quarks may finally yield to calculation.

Terms of use | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters