The Strange Story of Free Fractional Charge

The currently widely held wisdom is that quarks, the subatomic constituents that make up protons and neutrons, cannot be found in an unbound state, (i.e. roaming freely outside of a proton, neutron, or other particle made up of quarks). The reasoning goes that the attractive force due to the strong force between two quarks is so powerful that if they are separated far enough apart, there will be enough energy stored in the strong field to create two additional quarks that will immediately glom on to the two you were trying to separate in the first place, hence, no independent unbound quarks.

In 1977, however, Larue, Fairbank[1], and Hebard reported that they had found evidence indicating that free quarks did in fact exist[2]. Their experiment involved suspending a 1/4 mm superconducting niobium sphere in a magnetic field gradient[7] and causing it to oscillate in a vertical direction. The researchers measured the effects reversing the polarity of an applied electric field had on the sphere's oscillation frequency. Using this data, they were able to calculate how much free charge was present on the sphere. They wound up with the charge data shown below [3] (picture 2)

The scientific community at large, at least those who remember the work at all, tend to remember the penultimate incident in the history of the experiment. Luis Alvarez suggested that to remove any possibility that humans had tainted the data by performing subjective data cuts, random numbers should be added to a newly taken data set. That data was to be 'blind' analyzed and the results were to be reported. What most people will tell you is that the published results after this analysis were less than conclusive. What they'll leave out or don't know is that the published blind results contained a number of disclaimers that the graduate students in charge of the project had setup the apparatus incorrectly and that most of the inconclusiveness could just as easily be attributed to this poor setup.

In 1989 after two years of retirement, William Fairbanks returned to Stanford to perform more work on the fractional charge experiment. Sadly, he died soon thereafter on a morning jog after spending the night before working on the fractional charge experiment. In an obituary befitting the X-Files the New York Times reported

"Although Dr. Fairbank retired two years ago as physics professor at Stanford University, he had been at work there the night before his death, trying to verify his report of 11 years ago concerning the existence of individual subatomic particles called quarks."[4]

While there are claims that the experiment was reproduced by other researchers, there are interesting inconsistencies in their methods.

1. The follow-ons weren't done at liquid helium temperatures

2. A ferromagnetic levitation system utilizing iron covered niobium spheres was used instead of the superconducting levitation system used in Fairbank's experiments.

A few years later in 1997, quasi-particles, combinations of electrons that behave in manners inconsistent with the behavior of a single electron were found to exhibit charge equal to 1/3 that of an electron's. Is it possible that the experimental results of Fairbank et al. were a macroscopic demonstration or this behavior? Instead, did they actually see free quarks, or was it all just experimental error? What do you think?

References:

1. Other notes on William Fairbank

http://copaseticflow.blogspot.com/2013/05/gravitomagnetism-and-antigravity-for.html

2. Fractional Charge Indicated

http://dx.doi.org/10.1103%2FPhysRevLett.38.1011
LaRue G., Fairbank W. & Hebard A. (1977). Evidence for the Existence of Fractional Charge on Matter, Physical Review Letters, 38 (18) 1011-1014. DOI: 10.1103/PhysRevLett.38.1011

3.
http://dx.doi.org/10.1016%2F0168-9002%2888%2991113-8
Phillips J.D., Fairbank W.M. & Navarro J. (1988). Recent results in the search for fractional charge at Stanford, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 264 (1) 125-130. DOI: 10.1016/0168-9002(88)91113-8

4. New York Times Obituary for William Fairbank

http://www.nytimes.com/1989/10/03/obituaries/prof-william-n-fairbank-72-physicist-and-pioneer-in-quarks.html?pagewanted=1

5. arXiv open-access version of the quasi-particle discovery [pdf]

http://arxiv.org/pdf/cond-mat/9706307.pdf

6. National Academy of Sciences Bio of William Fairbank

http://nas.nasonline.org/site/DocServer/Fairbank_William.pdf?docID=79822

7. Superconducting levitation
http://copaseticflow.blogspot.com/2013/04/lenzs-law-induction-and-levitation.html

The Valentine's Day Magnetic Monopole

There's an assymetry to the form of the two Maxwell's equations shown in picture 1. While the divergence of the electric field is proportional to the electric charge density at a given point, the divergence of the magnetic field is equal to zero. This is typically explained in the following way. While we know that electrons, the fundamental electric charge carriers exist, evidence seems to indicate that magnetic monopoles, the particles that would carry magnetic 'charge', either don't exist, or, the energies required to create them are so high that they are exceedingly rare. That doesn't stop us from looking for them though! Keeping with the theme of Fairbank[1] and his academic progeny over the semester break, today's post is about the discovery of a magnetic monopole candidate event by one of the Fairbank's graduate students, Blas Cabrera[2]. Cabrera was utilizing a loop type of magnetic monopole detector. Its operation is in...

Cool Math Tricks: Deriving the Divergence, (Del or Nabla) into New (Cylindrical) Coordinate Systems

Now available as a Kindle ebook for 99 cents ! Get a spiffy ebook, and fund more physics The following is a pretty lengthy procedure, but converting the divergence, (nabla, del) operator between coordinate systems comes up pretty often. While there are tables for converting between common coordinate systems , there seem to be fewer explanations of the procedure for deriving the conversion, so here goes! What do we actually want? To convert the Cartesian nabla to the nabla for another coordinate system, say… cylindrical coordinates. What we’ll need: 1. The Cartesian Nabla: 2. A set of equations relating the Cartesian coordinates to cylindrical coordinates: 3. A set of equations relating the Cartesian basis vectors to the basis vectors of the new coordinate system: How to do it: Use the chain rule for differentiation to convert the derivatives with respect to the Cartesian variables to derivatives with respect to the cylindrical variables. The chain ...

More Cowbell! Record Production using Google Forms and Charts

First, the what : This article shows how to embed a new Google Form into any web page. To demonstrate ths, a chart and form that allow blog readers to control the recording levels of each instrument in Blue Oyster Cult's "(Don't Fear) The Reaper" is used. HTML code from the Google version of the form included on this page is shown and the parts that need to be modified are highlighted. Next, the why : Google recently released an e-mail form feature that allows users of Google Documents to create an e-mail a form that automatically places each user's input into an associated spreadsheet. As it turns out, with a little bit of work, the forms that are created by Google Docs can be embedded into any web page. Now, The Goods: Click on the instrument you want turned up, click the submit button and then refresh the page. Through the magic of Google Forms as soon as you click on submit and refresh this web page, the data chart will update immediately. Turn up the:...

Copasetic Flow

Search This Blog