Hadronization vs. the Big Rip (Part Two--Hadronization)

An interesting question led to an interesting thought and another excuse to invite two of my friends from my grad school days, BH and DB, over for some coffee and physics.

Celestial Mechanic: "When I was a grad student I regularly read Scientific American. One of the images that sticks with me was an ad that IBM ran for their Model 3081 mainframe systems. It showed an illustration of two alarm-clocks being smashed together and gears and springs flying everywhere. I'm talking about the classic spring-driven alarm clock with the two bells on top hit alternately by a hammer."

BH: "Like the one Garfield destroys all the time?"

CM: "Exactly! The ad used this image as a way of connecting with the use of the Model 3081 in particle physics laboratories to do the heavy number-crunching required. But there was one thing that disturbed me about that image. In particle physics we throw together the equivalent of alarm-clocks, but we never see any gears or springs. Let me put it this way: as an example in particle physics we throw an alarm-clock and an anti-alarm-clock together and get two alarm-clocks, two anti-alarm-clocks, and a whole bunch of wristwatches, but never any gears or springs. If we see a bunch of watches heading one way, we can infer that a spring started off in that direction, and if we see an alarm-clock and some wristwatches going another we might infer that a gear started off in that direction."

DB: "By 'gears and springs' you really mean quarks and gluons, right?"

CM: "Yes, I do."

DB: "So why don't we see free quarks and gluons?"

CM: "That's the $106,000 question right there. The mainstream answer is this: unlike electromagnetism or gravity, the strong force gets stronger when particles are drawn apart and weaker, in fact, it vanishes at zero distance.

CM: "So let's try a thought-experiment. Let's try to pull a quark out of a proton. As the target quark gets farther away, something strange happens. The chromodynamic fields between the target quark and the other two get stronger and they also get collimated into a tube-like structure. More and more energy must be expended as the quark is pulled away. Eventually enough energy has been added that there is enough to create a quark/antiquark pair. Well, more properly, there is enough energy to create the final state of a baryon and a meson, and the quark/antiquark pair to make it so is created along the flux tube which snaps, pulling the newly-created quark toward the other two and the newly-created antiquark towards our target quark. We tried to pull out a quark, but instead we end up pulling out a meson."

DB: "And that is why we never see free quarks and gluons: freeing one requires more than the energy required to create final states with more quark/antiquark pairs in them."

CM: "Exactly. And this process by which momentarily scattered quarks, antiquarks, and gluons regroup into the observed baryons and mesons, or hadrons as they are both called, is called hadronization."

BH: "And this is what you think will stop the big rip?"

CM: "Correct. The big rip scenario calls for the cosmological parameter to gradually increase until it becomes strong enough to overcome gravity at the galactic cluster level, then at the galactic level, then at the solar system level and finally it overwhelms gravity at the planetary and electromagnetism at the molecular level. At this time, it may even be strong enough to perturb the interiors of the nucleons, causing the masses of the proton and neutron to differ from their current values."

BH: "Will the masses increase or decrease? How will this affect the stability of nuclei?"

CM: "I'm not sure. Perhaps a simulation could be run with QCD on an expanding lattice."

DB: "Well, you've got a small network here. Maybe you could ditch OS/2 for Linux, turn your network into a Beowulf cluster and compute it yourself!"

CM: "Not likely. The computers are quite mismatched; the fastest machine is about 20 times faster than the slowest, an aging 486 system. I don't expect to be doing any massively parallel supercomputing any time soon. Still, this is a lot better than the Commodore 128 I had in college."

BH: "How time flies when you're having a good time!"

CM: "Right. Well, I'm going to need refill. How about you?"

DB: "Yes, time for another."

To be continued...

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