Andrew Yee
January 27th 06, 03:10 PM
Communications and Public Relations
Northeastern University
Contact:
Laura Shea, 617 373 5427
1-26-06
NU researchers find signs of extra dimensions
BOSTON, Mass. -- Researchers at Northeastern University and the University
of California, Irvine say that scientists might soon have evidence for
extra dimensions and other exotic predictions of string theory. Early
results from a neutrino detector at the South Pole, called AMANDA, show
that ghostlike particles from space could serve as probes to a world
beyond our familiar three dimensions, the research team says.
No more than a dozen high-energy neutrinos have been detected so far.
However, the current detection rate and energy range indicate that
AMANDA's larger successor, called IceCube, now under construction, could
provide the first evidence for string theory and other theories that
attempt to build upon our current understanding of the universe.
An article describing this work appears in the current issue of Physical
Review Letters. The authors are: Luis Anchordoqui, associate research
scientist in the Physics Department at Northeastern University; Haim
Goldberg, professor in the Physics Department at Northeastern University;
and Jonathan Feng, associate professor in the Department of Physics and
Astronomy at University of California, Irvine. The evidence, they say,
would come from how neutrinos interact with other forms of matter on
Earth.
"To find clues to support string theory and other bold, new theories, we
need to study how matter interacts at extreme energies," said Anchordoqui.
"Human-made particle accelerators on Earth cannot yet generate these
energies, but nature can in the form of the highest-energy neutrinos."
In recent decades, new theories have developed -- such as string theory,
extra dimensions and supersymmetry -- to bridge the gap between the two
most successful theories of the 20th century, general relativity and
quantum mechanics. Quantum mechanics describes three of the fundamental
forces of nature: electromagnetism, strong forces (binding atomic nuclei)
and weak forces (seen in radioactivity). It is, however, incompatible with
Einstein's general relativity, the leading description of the fourth
force, gravity. Scientists hope to find one unified theory to provide a
quantum description of all four forces.
Clues to unification, scientists say, lie at extreme energies. On Earth,
human-made particle accelerators have already produced energies at which
electromagnetic forces and weak forces are indistinguishable. Scientists
have ideas about how the next generation of accelerators will reveal that
strong forces are indistinguishable from the weak and electromagnetic at
yet higher energies. Yet to probe deeper to see gravity's connection to
the other three forces, still higher energies are needed.
Anchordoqui and his colleagues say that extragalactic sources can serve as
the ultimate cosmic accelerator, and that neutrinos from these sources
smacking into protons can release energies in the realm where the first
clues to string theory could be revealed.
Neutrinos are elementary particles similar to electrons, but they are far
less massive, have neutral charge, and hardly interact with matter. They
are among the most abundant particles in the universe; untold billions
pass through our bodies every second. Most of the neutrinos reaching Earth
are lower-energy particles from the sun.
AMANDA, funded by the National Science Foundation, attempts to detect
neutrinos raining down from above but also coming "up" through the Earth.
Neutrinos are so weakly interacting that some can pass through the entire
Earth unscathed. The total number of "down" and "up" neutrinos is
uncertain; however, barring exotic effects, the relative detection rates
are well known.
AMANDA detectors are positioned deep in the Antarctic ice. The NSF-funded
IceCube has a similar design, only it has about six times more detectors
covering a volume of one cubic kilometer. A neutrino smashing into atoms
in the ice will emit a brief, telltale blue light; and using the
detectors, scientists can determine the direction where the neutrino came
from and its energy.
The key to the work presented here is that the scientists are comparing
"down" to "up" detections and looking for discrepancies in the detection
rate, evidence of an exotic effect predicted by new theories.
"String theory and other possibilities can distort the relative numbers of
'down' and 'up' neutrinos," said Jonathan Feng. "For example, extra
dimensions may cause neutrinos to create microscopic black holes, which
instantly evaporate and create spectacular showers of particles in the
Earth's atmosphere and in the Antarctic ice cap. This increases the number
of 'down' neutrinos detected. At the same time, the creation of black
holes causes 'up' neutrinos to be caught in the Earth's crust, reducing
the number of 'up' neutrinos. The relative 'up' and 'down' rates provide
evidence for distortions in neutrino properties that are predicted by new
theories."
"The neutrinos accelerated in the cosmos to energies unattainable on Earth
can detect the 'footprint' of new physics," said Goldberg. "The 'body'
responsible for the footprint can then emerge through complementary
experiments at the new generation of human-made colliders. On all fronts,
it is an exciting era in high-energy physics."
More information about AMANDA and IceCube is available at the IceCube
website,
http://www.icecube.wisc.edu
About Northeastern: Northeastern University, located in the heart of
Boston, Massachusetts, is a world leader in practice-oriented education
and recognized for its expert faculty and first-rate academic and research
facilities. Northeastern integrates challenging liberal arts and
professional studies with the nation's largest cooperative education
program. Through co-op, Northeastern undergraduates alternate semesters of
full-time study with semesters of paid work in fields relevant to their
professional interests and major, giving them nearly two years of
professional experience upon graduation. The majority of Northeastern
graduates receive a job offer from a co-op employer. Cited for excellence
four years running by U.S. News & World Report, Northeastern has quickly
moved up into the top tier rankings -- an impressive 35 spots in four
years. In addition, Northeastern was named a top college in the 2006
edition of the Princeton Review's annual "Best Colleges" issue. For more
information, please visit http://www.northeastern.edu .
Northeastern University
Contact:
Laura Shea, 617 373 5427
1-26-06
NU researchers find signs of extra dimensions
BOSTON, Mass. -- Researchers at Northeastern University and the University
of California, Irvine say that scientists might soon have evidence for
extra dimensions and other exotic predictions of string theory. Early
results from a neutrino detector at the South Pole, called AMANDA, show
that ghostlike particles from space could serve as probes to a world
beyond our familiar three dimensions, the research team says.
No more than a dozen high-energy neutrinos have been detected so far.
However, the current detection rate and energy range indicate that
AMANDA's larger successor, called IceCube, now under construction, could
provide the first evidence for string theory and other theories that
attempt to build upon our current understanding of the universe.
An article describing this work appears in the current issue of Physical
Review Letters. The authors are: Luis Anchordoqui, associate research
scientist in the Physics Department at Northeastern University; Haim
Goldberg, professor in the Physics Department at Northeastern University;
and Jonathan Feng, associate professor in the Department of Physics and
Astronomy at University of California, Irvine. The evidence, they say,
would come from how neutrinos interact with other forms of matter on
Earth.
"To find clues to support string theory and other bold, new theories, we
need to study how matter interacts at extreme energies," said Anchordoqui.
"Human-made particle accelerators on Earth cannot yet generate these
energies, but nature can in the form of the highest-energy neutrinos."
In recent decades, new theories have developed -- such as string theory,
extra dimensions and supersymmetry -- to bridge the gap between the two
most successful theories of the 20th century, general relativity and
quantum mechanics. Quantum mechanics describes three of the fundamental
forces of nature: electromagnetism, strong forces (binding atomic nuclei)
and weak forces (seen in radioactivity). It is, however, incompatible with
Einstein's general relativity, the leading description of the fourth
force, gravity. Scientists hope to find one unified theory to provide a
quantum description of all four forces.
Clues to unification, scientists say, lie at extreme energies. On Earth,
human-made particle accelerators have already produced energies at which
electromagnetic forces and weak forces are indistinguishable. Scientists
have ideas about how the next generation of accelerators will reveal that
strong forces are indistinguishable from the weak and electromagnetic at
yet higher energies. Yet to probe deeper to see gravity's connection to
the other three forces, still higher energies are needed.
Anchordoqui and his colleagues say that extragalactic sources can serve as
the ultimate cosmic accelerator, and that neutrinos from these sources
smacking into protons can release energies in the realm where the first
clues to string theory could be revealed.
Neutrinos are elementary particles similar to electrons, but they are far
less massive, have neutral charge, and hardly interact with matter. They
are among the most abundant particles in the universe; untold billions
pass through our bodies every second. Most of the neutrinos reaching Earth
are lower-energy particles from the sun.
AMANDA, funded by the National Science Foundation, attempts to detect
neutrinos raining down from above but also coming "up" through the Earth.
Neutrinos are so weakly interacting that some can pass through the entire
Earth unscathed. The total number of "down" and "up" neutrinos is
uncertain; however, barring exotic effects, the relative detection rates
are well known.
AMANDA detectors are positioned deep in the Antarctic ice. The NSF-funded
IceCube has a similar design, only it has about six times more detectors
covering a volume of one cubic kilometer. A neutrino smashing into atoms
in the ice will emit a brief, telltale blue light; and using the
detectors, scientists can determine the direction where the neutrino came
from and its energy.
The key to the work presented here is that the scientists are comparing
"down" to "up" detections and looking for discrepancies in the detection
rate, evidence of an exotic effect predicted by new theories.
"String theory and other possibilities can distort the relative numbers of
'down' and 'up' neutrinos," said Jonathan Feng. "For example, extra
dimensions may cause neutrinos to create microscopic black holes, which
instantly evaporate and create spectacular showers of particles in the
Earth's atmosphere and in the Antarctic ice cap. This increases the number
of 'down' neutrinos detected. At the same time, the creation of black
holes causes 'up' neutrinos to be caught in the Earth's crust, reducing
the number of 'up' neutrinos. The relative 'up' and 'down' rates provide
evidence for distortions in neutrino properties that are predicted by new
theories."
"The neutrinos accelerated in the cosmos to energies unattainable on Earth
can detect the 'footprint' of new physics," said Goldberg. "The 'body'
responsible for the footprint can then emerge through complementary
experiments at the new generation of human-made colliders. On all fronts,
it is an exciting era in high-energy physics."
More information about AMANDA and IceCube is available at the IceCube
website,
http://www.icecube.wisc.edu
About Northeastern: Northeastern University, located in the heart of
Boston, Massachusetts, is a world leader in practice-oriented education
and recognized for its expert faculty and first-rate academic and research
facilities. Northeastern integrates challenging liberal arts and
professional studies with the nation's largest cooperative education
program. Through co-op, Northeastern undergraduates alternate semesters of
full-time study with semesters of paid work in fields relevant to their
professional interests and major, giving them nearly two years of
professional experience upon graduation. The majority of Northeastern
graduates receive a job offer from a co-op employer. Cited for excellence
four years running by U.S. News & World Report, Northeastern has quickly
moved up into the top tier rankings -- an impressive 35 spots in four
years. In addition, Northeastern was named a top college in the 2006
edition of the Princeton Review's annual "Best Colleges" issue. For more
information, please visit http://www.northeastern.edu .