Huntress of the Higgs boson

Dr. Sau Lan Wu

How many objects are not made of anything smaller? In the entire universe, three alone are indivisible. Only this trio of stable entities are fundamental.

Such an idea of elementary indivisible objects began with the ancient Greek thinker Democritus. Born in 460 BCE, he was widely called the laughing philosopher because of his emphasis on cheerfulness, and also because he lived too early to have seen last week’s presidential debate.

Democritus said that the world is composed of indivisible particles that he called atoms. By the late 19th century, scientists realized that not only do atoms exist, they are also made of yet smaller entities. The first of these to be discovered was the electron, in 1899. Then came the proton, then the neutron, and eventually a host of smaller short-lived particles.

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Of these, only electrons are fundamental and cannot be split into anything smaller. Some, like the neutron, are so stable that they live forever, as long as they stay within their protective atom. Others are so ephemeral that they disintegrate and vanish within a tiny fraction of a second after they are created.

A quarter-century ago, we learned that protons and neutrons are made of still tinier objects called quarks, which in everyday life always come in threes. Quarks are fundamental particles: They cannot be split into anything else. Although there are six varieties of quarks, discovered between 1968 and 1995, only two – the up and the down quark – are stable. These arrange themselves into protons and neutrons, made of three quarks apiece. (I hope that you’re writing this down.)

To review, electrons are fundamental particles, and so are quarks. The final common indivisible particle, and the one with the lightest weight, is the neutrino. This is the most prevalent particle in the universe. Created in the fusion furnace that occupies the innermost 24 percent of the Sun, neutrinos burst out from the Sun in unimaginable torrents. They are everywhere. Nothing stops them. A trillion neutrinos fly through each of your fingernails every second. Each neutrino passes through our planet in a twentieth of a second without being slowed down in the slightest.

Our understanding has come a long way, and when this year dawned we felt that 17 types of subatomic particles explain everything that we know about matter – known matter, that is. Some unknown Dark matter is almost certainly shoving around stars and galaxies throughout the cosmos. Separate “supersymmetry” theories think that it is composed of an invisible hypothesized entity named the neutralino.

Yes, 17 subatomic varieties. But only 16 had been observed. The one missing particle was expected to answer the nagging question: Why do particles weigh what they do? Why should a quark weigh 612 times more than an electron? The masses of the various particles have always seemed arbitrary.

About a half-century ago, theoretical physicist Peter Higgs suggested that there must exist a particle whose purpose is to bestow and regulate the mass of all other particles. Ever since then, the hunt has been on for the “Higgs boson.”

This past summer it was finally found. The story of finding the Higgs boson, and what it means, will be the subject of a lecture at Vassar given by one of its discoverers. This is Vassar alumna Sau Lan Wu, who had previously found two other particles as well, including one of the quarks.

Because she is so widely respected and now celebrated for her discovery, this is a compelling event. On Monday, October 22 at 5 p.m. in Vassar’s Rockefeller Hall, Room 300, Dr. Wu will discuss the decades of international effort that led to this research breakthrough. With this discovery, we finally have a complete picture of the behavior of matter and energy at the most fundamental levels.

Dr. Sau Lan Wu will speak about the discovery of the Higgs boson on Monday, October 22 at 5 p.m. in Rockefeller Hall, Room 300, on the Vassar campus. For more information on this free lecture, call (845) 437-5370. Vassar College is located at 124 Raymond Avenue in Poughkeepsie, and directions to the campus can be found at https://www.vassar.edu/directions.

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