Which statement is correct? A - AQA - A-Level Physics - Question 12 - 2022 - Paper 1

To determine the correct statement, we can analyze each option based on our understanding of particle physics.

1. A. All strange particles are mesons.

   • This statement is incorrect. While strange particles include mesons, there are also baryons (e.g., hyperons) that contain strange quarks.

2. B. Strange particles are always created in pairs.

   • This statement is correct. Strange quarks are produced in pairs, as per the principles of quantum chromodynamics, which states that quarks are never found in isolation.

3. C. Strangeness can only change in strong interactions.

   • This is incorrect. Strangeness can change in weak interactions as well, particularly during decay processes involving strange quarks.

4. D. Strangeness can only have a value of 0 or -1.

   • This statement is also incorrect. Strangeness can take values such as 1 or higher (for certain strange baryons) and -1 for antiparticles. Therefore, this is not a comprehensive description.

Hence, the only accurate statement among the options provided is option B, which acknowledges the pairing nature of strange particle production.