From Fermilab Today: “CMS Result – Precision smashing”


Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

Friday, Sept. 14, 2012
Jim Pivarski

It is sometimes said that if particle physicists wanted to figure out how an expensive Swiss watch works, they would smash it and deduce its structure from the cogs, springs and glass that fly apart.

[The first place I saw this what? analogy? metaphor? was in the 1985 PBS video Creation of the Universe with Timothy Ferris describing Lawrence’s first hand held collider. I just watched this video again the other day. It still holds up quite well.]

To understand the inner life of protons, this is exactly what they do—smash two of them together and analyze the aftermath. It is not as ridiculous as it sounds. The basic laws of energy and momentum conservation make a precision science of this violent practice.

collision
Analyzing jets from a particle collision is something like analyzing the aftermath of the collision of two pocket-watches. CMS scientists recently analyzed collisions in which hundreds of particles seemed to be channeled into six streams.No image credit

Energy and momentum are both quantities that describe the inertia of an object or a system of particles. Energy is the sum of motion in all directions, while momentum is the net motion, depending on direction.

In a recent paper, CMS scientists applied an extreme version of this technique. They looked at events in which hundreds of visible particles seemed to be channeled in six streams, known as jets. Assuming that each jet was caused by a cascade of decays, starting from a single quark, they applied energy and momentum conservation to find out if triplets of quarks descended from an as-yet unknown particle.”

ru
The Rutgers physicists pictured above were all major contributors to this analysis.

See the full article here.

Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.


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