collapse

Author Topic: Northeastern University Researchers Find Signs of Extra Dimensions  (Read 723 times)

Offline zorgon

  • Administrator
  • Hero Member
  • *****
  • Posts: 19911
  • Gold 879
Northeastern University Researchers Find Signs of Extra Dimensions

Pretty sure I did this one here somewhere but am reposting it to use for the website updates



Posted on January 26, 2006 by woit
If you believe the headline of a press release issued today by Northeastern University, its researchers have found evidence of extra dimensions. The actual text of the press release tells a different story, that they haven’t found evidence of extra dimensions. One can’t blame the headline writer too much though, because the text itself is full of enough hype and nonsense about string theory and extra dimensions to confuse most people.

According to the press release text:

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.

… 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…

“To find clues to support string theory and other bold, new theories, we need to study how matter interacts at extreme energies,” said Anchordoqui…

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…

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….

“String theory and other possibilities can distort the relative numbers of ‘down’ and ‘up’ neutrinos,” said Jonathan Feng.

The half a dozen references to string theory in the short press release might lead the gullible to think that we’re about to be provided with evidence for the “exotic predictions of string theory”, but that has little relationship to the reality here, one aspect of which of course is that there are no “predictions of string theory” about any of this.

The occasion of the press release is the appearance in Physical Review Letters of a paper by Anchordoqui, Feng and Goldberg entitled Particle Physics on Ice: Constraints on Neutrino Interactions Far Above the Weak Scale. The authors discuss the possibility of using the difference between up and down observed rates for collisions of ultra-high energy cosmic ray neutrinos to get information about neutrino cross-sections at around 6 Tev center of mass energy, far above the energy scale for which we now have data about these cross-sections. They conclude that the data from the AMANDA array operating at the South Pole since 2000 already provide some constraints, and that IceCube, the next generation array now being installed there, could at 90% confidence level rule out a 40% enhancement of the neutrino cross-section over the Standard Model values.

What’s interesting here is not that extra dimensions have been found, but rather the opposite. AMANDA results show no evidence of the kind of enhanced cross-sections you might expect from some extra-dimensional scenarios, and it seems possible that IceCube will rule out such extra dimensions at energies accessible by the LHC even before the LHC comes on line. For a similar but earlier argument of this kind, see a discussion by Jacques Distler a year and a half ago concerning an earlier paper by these same authors that argues that the Pierre Auger Observatory, another cosmic ray observatory now taking data, may also be able to rule out extra dimensions observable at LHC energies before the LHC is turned on.

There’s also some mention of this over at Lubos Motl’s blog, with half the posting devoted to scatological attacks on this blog and its readers. I really think he’s losing it. Note that following current arXiv policy, a trackback linking to Lubos’s posting has appeared at the arXiv listing for the Anchordoqui et. al. paper, but no such trackback will be allowed to appear to the posting you are now reading.

Update: One of the problems with the endless number of absurdly overhyped press releases about string theory is that they get widely distributed.

Update: The Slashdot article does contain a useful extended comment from someone working for AMANDA/IceCube.

Update: The headline on the press release has been changed by the people at Northeastern. It now reads “NU researchers say South Pole detector could yield signs of extra dimensions “.



Northeastern University Researchers Find Signs of Extra Dimensions
« Last Edit: February 22, 2015, 01:04:23 PM by zorgon »

Offline zorgon

  • Administrator
  • Hero Member
  • *****
  • Posts: 19911
  • Gold 879
Re: Northeastern University Researchers Find Signs of Extra Dimensions
« Reply #1 on: February 22, 2015, 01:07:13 PM »
South pole detector could yield signs of extra dimensions
NC&T/NU



IceCube will occupy a volume of one cubic kilometer. IceTop located at the surface, comprises an array of sensors to detect air showers. It will be used to calibrate IceCube and to conduct research on high-energy cosmic rays. (Photo: Steve Yunck)

Quote
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."

South pole detector could yield signs of extra dimensions

 


Wal-Mart.com USA, LLC
affiliate_link
Free Click Tracking
Wal-Mart.com USA, LLC

* Recent Posts

Re: Mark Hamill is left stunned by new Star Wars - The Last Jedi by thorfourwinds
[January 23, 2018, 07:46:49 PM]


Re: Mark Hamill is left stunned by new Star Wars - The Last Jedi by petrus4
[January 23, 2018, 04:28:31 PM]


‘Massive object HUNDREDS of miles long’ spotted on NASA live feed before was cut by rdunk
[January 23, 2018, 03:20:23 PM]


Re: 411 by ArMaP
[January 23, 2018, 02:22:47 PM]


Re: 411 by ArMaP
[January 23, 2018, 02:08:00 PM]


Re: 411 by Gigas
[January 23, 2018, 12:39:05 PM]


Re: 411 by Irene
[January 23, 2018, 12:01:21 PM]


Re: By the stars, John Lear makes a headline on Rense by Gigas
[January 23, 2018, 11:57:08 AM]


Re: Mark Hamill is left stunned by new Star Wars - The Last Jedi by Irene
[January 23, 2018, 11:52:34 AM]


Re: 411 by Gigas
[January 23, 2018, 11:36:55 AM]


Re: By the stars, John Lear makes a headline on Rense by zorgon
[January 23, 2018, 11:30:57 AM]


Re: 411 by Irene
[January 23, 2018, 10:11:52 AM]


Re: 411 by Irene
[January 23, 2018, 10:03:10 AM]


Re: 411 by Irene
[January 23, 2018, 10:02:14 AM]


Re: The X Files series by micjer
[January 23, 2018, 06:32:49 AM]


Re: 411 by ArMaP
[January 23, 2018, 05:33:17 AM]


Re: 411 by ArMaP
[January 23, 2018, 05:32:17 AM]


Re: By the stars, John Lear makes a headline on Rense by ArMaP
[January 23, 2018, 02:18:27 AM]


Mark Hamill is left stunned by new Star Wars - The Last Jedi by A51Watcher
[January 23, 2018, 02:15:59 AM]


Re: 411 by Gigas
[January 22, 2018, 11:17:13 PM]