SETI bioastro: Fw: Physics News Update 617

New Message Reply Date view Thread view Subject view Author view Attachment view

From: LARRY KLAES (ljk4@msn.com)
Date: Fri Dec 13 2002 - 12:54:31 PST


----- Original Message -----
From: physnews@aip.org
Sent: Friday, December 13, 2002 2:54 PM
To: ljk4@MSN.COM
Subject: Physics News Update 617

PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 617 December 13, 2002 by Phillip F. Schewe, Ben Stein, and James
Riordon

PHYSICS STORIES OF 2002. The top two physics stories for the past 12
months were the total accounting of neutrinos from the sun by the Sudbury
Neutrino Observatory (SNO), thus solving the solar neutrino problem (Update
586; www.aip.org/enews/physnews/2002/split/586-1.html); and the formation
and detection of antihydrogen atoms at CERN (Updates 605 and 611,
www.aip.org/enews/physnews/2002/split/605-1.html and
www.aip.org/enews/physnews/2002/split/611-1.html). Other notable physics
developments for the year include stopping and storing light in a solid
(Update 571), the observation of phase-transition behavior in nuclei (572),
publication of some unsent letters by Niels Bohr to Werner Heisenberg (576),
interferometry with C-70 molecules (579), a dispute over "fusion" in
sonoluminescence (579, 599), most precise tests of special relativity (571,
590), sharper maps of the cosmic microwave background (591), "droplet" of
light (596), claims for element 118 retracted (597), verification of the
notion that the second law of thermodynamics can be violated on small
spacetime intervals (598), high precision measurements of CP violation in B
meson decays and in the g-2 factor of the muon (600), scandal at Lucent
(606), record high laboratory magnetic fields (614), polarization in the
cosmic microwave background detected (606), 2002 Nobel prize for physics
(608), noise can improve balance (612), and longest measured atomic lifetime
(616). All the above Update items can be retrieved from our archive at
www.aip.org/physnews/update.

REACTOR ANTI-NEUTRINO DISAPPEARANCE, measured by a detector in Japan,
supports the idea that neutrinos oscillate from one type to another and that
they possess mass. Nuclear reactors produce several things: heat,
electricity, spent fuel rods, and neutrinos. The neutrinos (or, to be more
exact, electron anti-neutrinos) are a result of fission reactions inside the
reactor core. But some of the electron antineutrinos, once they're underway
and moving through the Earth, manifest one of the weirdest phenomena in all
of physics, namely the ability to exist as a composite of several
sub-species. That is, what we call a neutrino is really several (perhaps
three) neutrinos in one. At any point along its trajectory the generic
neutrino might (if you were to capture it just then) appear as an electron
neutrino, but farther along it might look like a muon neutrino, in which
case it would elude detectors tuned to detect only electron nu's.
The Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND) sets out
to sample this odd mode of being. The apparatus, basically a huge reservoir
of optically-active liquid viewed by numerous phototubes, looks for
interactions in which an incoming nu strikes a proton, creating in their
stead a trackable neutron-positron pair. KamLAND resides in an underground
lab beneath Toyama, Japan. It is a sort of telescope peering not at
galaxies in the sky; instead it stares through a block of terrestrial crust
looking for the neutrino warmth cast off by a constellation of 69 reactors
in Japan and Korea.
Taking into account the laws of physics governing the reactions in the
reactor cores, the known power ratings for the reactors, their aggregate
reactor-detector distances, and the duration of the experiment (145 days),
one would expect seeing 86 true events, whereas the actual number was 54.
The researchers conclude that the disappearance of events is due to neutrino
oscillation.
This result is not merely a confirmation of oscillation research carried
out with solar nu's at such detectors as Super Kamiokande in Japan and the
Sudbury Neutrino Observatory (SNO) in Canada (see Update 586,
http://www.aip.org/enews/physnews/2002/split/586-1.html). For one thing
KamLAND studies anti-neutrinos rather than neutrinos. Furthermore, the
production of neutrinos in a reactor is much closer at hand and better
understood than is the case for the sun. The KamLAND finding also serves to
narrow the theoretical explanation of the neutrino's split personality.
(Eguchi et al., paper submitted to Physical Review Letters, text and
background information at:
http://hep.stanford.edu/neutrino/KamLAND/KamLAND.html)

ION-CHANNEL PROTEINS, which act as a sort of circuit element, allowing the
flow of ions in and out of cells, can now be scrutinized in a new way that
exploits technology operative at the single-molecule level. Scientists from
the Center for NanoScience (CeNS) at the Ludwig-Maximilians-University in
Munich don't make electrical contact with cells in the customary way by
pressing an electrolyte-filled glass micro-pipette against the cell
membrane. Instead they allow individual cells to settle down onto a glass
gasket covered with micron-sized pores, allowing the ion-channels to
protrude out the bottom (see figure at www.aip.org/mgr/png). This
chip-based architecture, the researchers believe, will more easily
facilitate an automated biotech-nanotech approach to ion-channel research,
which in turn is important for understanding how cells exchange information
in various nervous, cardiovascular, intestinal, and reproductive processes.
(Fertig et al., Applied Physics Letters, 16 December 2002)

***********
PHYSICS NEWS UPDATE is a digest of physics news items arising
from physics meetings, physics journals, newspapers and
magazines, and other news sources. It is provided free of charge
as a way of broadly disseminating information about physics and
physicists. For that reason, you are free to post it, if you like,
where others can read it, providing only that you credit AIP.
Physics News Update appears approximately once a week.

AUTO-SUBSCRIPTION OR DELETION: By using the expression
"subscribe physnews" in your e-mail message, you
will have automatically added the address from which your
message was sent to the distribution list for Physics News Update.
If you use the "signoff physnews" expression in your e-mail message,
the address in your message header will be deleted from the
distribution list. Please send your message to: listserv@listserv.aip.org

(Leave the "Subject:" line blank.)


New Message Reply Date view Thread view Subject view Author view Attachment view

This archive was generated by hypermail 2.1.2 : Mon Dec 16 2002 - 21:29:31 PST