Question

Is there a fundamental difference between up quarks and strange quarks beside their mass?

Answer 1

Yes, besides their mass difference, up quarks and strange quarks have other distinct properties. Here are a few fundamental differences between up quarks and strange quarks:

1. Electric Charge: Up quarks have a positive electric charge of +2/3e, where "e" represents the elementary charge. Strange quarks also have a charge of +2/3e, just like up quarks. The electric charge of quarks is a fundamental property that determines their electromagnetic interactions.

2. Flavor Quantum Number: Quarks are characterized by a property known as flavor, which distinguishes them from one another. Up quarks have a flavor quantum number of +1, while strange quarks have a flavor quantum number of -1. This flavor property is conserved in strong and electromagnetic interactions, meaning that the total flavor value is constant during particle interactions.

3. Decay Modes: Up quarks are stable and do not undergo decay through the strong nuclear force. Strange quarks, on the other hand, can undergo weak decays through the weak nuclear force, such as the decay of strange quarks into down quarks. This difference in decay modes is due to the differing properties and masses of the quarks.

4. Flavor-Changing Interactions: Strange quarks can participate in flavor-changing interactions, where they can change into up or down quarks through weak interactions. This process is known as flavor oscillation or flavor-changing neutral current (FCNC). Up quarks, being lighter, are not involved in such flavor-changing interactions.

5. Production and Abundance: Up quarks are more common in ordinary matter, making up the majority of the quarks found in protons and neutrons. Strange quarks are less abundant and are typically found in more exotic particles and environments, such as in strange hadrons or produced in high-energy particle collisions.

While up quarks and strange quarks share similarities in terms of electric charge, they possess distinct flavor quantum numbers, have different decay behaviors, and exhibit differences in their participation in flavor-changing interactions. These differences contribute to their distinct roles in particle physics and the formation of different types of hadrons.