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Homework Help: What is hadron composition given strangeness and mass

  1. Nov 9, 2008 #1
    1. The problem statement, all variables and given/known data
    This is from Advanced Physics by Adams and Alday, section 9.11, question 2 c.

    What is the quark content of [snip] Λ baryon, strangeness = -1, mass 1.12 GeV/c2?

    2. Relevant equations
    No equations. Table of masses at http://en.wikipedia.org/wiki/List_of_particles. Strangeness of s quark is -1 and anti-s quark is +1

    3. The attempt at a solution
    A baryon, so composed of three qwarks or three anti-quarks.

    The strangeness of -1 requires an s quark so the other two quarks cannot be anti-quarks.

    The s quark has mass 104 MeV leaving 1.016 GeV for the other two quarks. I cannot find any combination of quarks that adds up to ~1 GeV.

    The book lists uds (all anti-quarks) as the answer but an anti-s would have strangeness +1 and the mass of mass of uds is 2.4 MeV + 4.8 MeV + 104 MeV = 111 MeV which is ~ a tenth of the given mass.

    I do not understand how the book's answers to part a and b of the question can be correct either but chose this as a sample to ask about.
    Last edited: Nov 9, 2008
  2. jcsd
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