Pions are the lightest mesons, with mass some 270 times that of the electron. Charged pions decay typically into a muon and a neutrino or antineutrino. This makes pion beams useful for producing beams of neutrinos, which physicists use to study those elusive particles. In a medical application during the late 20 th century, accelerator centers installed "biomedical beam lines" to test pions for cancer therapy. In these experiments, pions attached themselves to atomic nuclei within cancer cells. The nuclei would literally explode, delivering a "pion star" of cancer-killing nuclear debris. Unfortunately, results were not as encouraging as hoped, and enthusiasm for this technique has waned. The quark composition of the negative pion is a. uud. b. \(d \bar{u}\) c. ud. d. \(c \bar{c}\)

Step by step solution

01

Understanding Quarks and Antiquarks

Quarks are the most basic units of matter. A pion is a meson, which means it is composed of a quark and an antiquark. Antiquarks are the antimatter counterparts to quarks.

02

Identifying quark compositions

The negative pion, also known as the Pi Minus pion (\(π^-\)), contains a down quark and an up antiquark. This makes option b, which lists this combination (\(d \bar{u}\)), the correct answer.

03

Recognizing Incorrect Options

Options a and c list three quarks and two quarks respectively which are compositions associated with baryons and mesons, not pions. Option d lists charm quarks and antiquarks, which doesn't correspond to the composition of a negative pion.

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