The standard model of particle physics is a self-contained picture of fundamental particles and their interactions. Physicists, on a journey from solid matter to quarks and gluons, via atoms and nuclear matter, may have reached the foundation level of fields and particles. But have we reached bedrock, or is there something deeper? Savas Dimopoulos
While in the post previous to this I gave some indication of the gravity from the cosmological point of view, I then took it down to the particle collisions. I again reiterate this, in this post as well.
Newton’s inverse-square (1/r2) law is a cornerstone of General Relativity. However, this law has been challenged by many modern theories of gravity and particle physics. The supergravity and unified field theories often run into a new short-range force, with an accompanying new particle, which should appear as a violation of the 1/r2 law. More recently, a possible violation of the 1/r2 law in the range below 1 mm was suggested by string theories with extra dimensions.
Two masses at a given distance place equal and opposite forces of attraction on one another. The magnitude of this force of attraction is given by:
where G is the universal gravitation constant (6.67 X 10-11 Nm2/kg2), m1 is the mass of the first object in kilograms, m2 is the mass of the second object in kilograms, and r is the distance between the centers of the two masses, in meters.
It is not without thinking here that what you thought of the “microstate blackhole,” could have found it’s relevance in the temperatures reached, when seen at this level?
Fig. 1. In quantum chromodynamics, a confining flux tube forms between distant static charges. This leads to quark confinement – the potential energy between (in this case) a quark and an antiquark increases linearly with the distance between them.
The ideal experimental test of this new feature of QCD would be to study the flux tube of figure 1 directly by anchoring a quark and antiquark several femtometres apart and examining the flux tube between them. In such ideal circumstances, one of the characteristics of the gluonic flux tube would be the model-independent spectrum shown in figure 2. The excitation energy is p/r because the flux tube’s mass is entirely due to its stored energy. There are two initially excited longest wavelength vibrations with identical energies because the motion of the flux tube is in the two symmetrical dimensions perpendicular to its length.
You ever hear of the term, “you can’t hit the broad side of a barn?” WEll lets think about this when it comes to the measures of femtometres and such. Classically old, it was not witout some direction in thinking that one could be taken down to certain measures for those same considerations. Barn Yard?
Origin of the (classified) barn
In the luminosity lexicon, a picobarn is one trillionth (10-12) of a barn, and a femtobarn is one quadrillionth (10-15) of a barn… but what’s a barn? The distinctive and amusing term originated with two Purdue University physicists working on the Manhattan Project in 1942—and it was classified information by the US government until after World War II.
A History of Physics at Purdue (Gartenhaus, Tubis, Cassidy, and Bray) cites the July 1972 issue of Physics Today in which Marshall Halloway and Charles Baker write of tossing around ideas over dinner until arriving at “barn” to describe the typical nuclear cross section of 10-24 cm2, the effective target area that a nuclear particle represents in a collision. Dining in the Purdue Memorial Union, back in Lafayette, Indiana, Halloway and Baker dismissed “Oppenheimer” and “Bethe” as candidates, then considered John Manley, director of the Purdue group at Los Alamos. They decided “Manley” was too long, and then, as the authors put it in the Physics Today article to:
So here we are looking at what the EOT-WASH GROUP is doing? What is “compactification” in line with any thinking, that the world around us from a cosmological point of view is large(large circle), and that amidst it’s reality, exists this finer world of particulars that “we’d only imagine” while the measures to it’s finest(small circle) was produce and then energies assigned.
It would be as if you looked at the cosmos and never thought about it constituents “bits and pieces,” which make up those cosmological processes. Yet, for me, “circles within circles” would have made me wonder which circle represented which part of the views at any one time, whilst we speak about these energies from one perspective to the next.
Savas Dimopoulos:At close encounter the particles can exchange gravitons via the two extra dimensions, which changes the force law at very short distances. Instead of the “Newtonian inverse square law” you’ll have an inverse fourth power law. This signature is being looked for in the ongoing experiments.
…..and more here for how perspectve can change once you give a direction in which to think about.
Savas Dimopoulos:At first we faced denial. We had deliberately used the word “sub-millimeter” in our first paper. Physicists were surprised, to say the least, that such a thing was not already excluded experimentally. I remember a stage in 1998 when colleagues wondered if we had not forgotten some crucial experiment. We were not discouraged. No! We gave talks on the ideas, and by July 1998 had analyzed the laboratory and cosmological constraints. That paper marked a sea-change in opinion: physicists began to think this was an interesting idea. By the fall of 1998 we were showing how to do real physics. Now several study groups are taking us very seriously: the high citation rates speak for themselves.
Personally I am not surprised by the reaction. Revolutionary ideas go through a cycle: denial, followed by “okay it is consistent but can you do anything with it?” and finally, once you show how to do real physics, you may get the third phase where many physicists become interested in the field. The same thing happened to me and Giorgi back in 1981 when we first proposed the supersymmetric extension of the standard model of particle physics. Initially there were the usual skeptics but now it is completely accepted.
Oddly, for me, the major competitor to these proposals for extra dimensions is the supersymmetry extension. But let’s recall some of the disadvantages of the standard model. First, it shuts out gravity. Second, it has 18 free parameters, many of them very small. Third, the vacuum energy is 120 orders of magnitude larger than what you would naively guess from the standard model.
Proposing extra dimensions to space is a drastic step. But once you have the extra space you can attribute the smallness of some quantities to the statement that their origin is somewhere far away inside space, just as an astronomer might attribute the faintness of a galaxy to its large distance. For example, maybe the smallness of the electron mass arises because its origin is far away inside the extra dimensions.
My view is that both of the big ideas I have worked on are testable in the next decade by LHC. The two frameworks have complementary features. I’m greatly looking forward to the outcome
Make sure you look at the “compactification” label to the right index