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Bottom Quark

Bottom Quark. Patricia Thrasher. Quark Basics. Strong force, Electromagnetic, Weak, Gravitational Total of 3 generations Quarks make matter Bottom quark possess all four forces Decays into up and charm quark Mass 4.13 ~ 4.37 GeV/c 2 Electric charge -1/3 e. Cabibbo Matrix.

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Bottom Quark

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  1. Bottom Quark Patricia Thrasher

  2. Quark Basics • Strong force, Electromagnetic, Weak, Gravitational • Total of 3 generations • Quarks make matter • Bottom quark possess all four forces • Decays into up and charm quark • Mass 4.13 ~ 4.37 GeV/c2 • Electric charge -1/3 e

  3. Cabibbo Matrix • Unitary Matrix • Incorporates two generations of quarks • Cabibbo angle related to probability that down and strange quarks decay into up quark.

  4. Prediction of New Quark • Kobayashi and Maskawa postulate a third family • Parameters for CP violation: three rotation angles and one phase • Kobayashi and Maskawa awarded Nobel Prize in Physics for their work on broken symmetry V =

  5. CKM Matrix • CP violation couldn’t be explained by Cabibbo matrix. Kobayashi and Maskawa added third generation to keep track of weak decays • CKM helps understand asymmetry in matter and antimatter • The transition probability from quark i to quark j is proportional to the magnitude squared of the elements of the matrix Vij

  6. C and P • Charge conjugation turns particle into antiparticle • Parity changes a right-hand coordinate system to a left-hand system • C = -1 L + S odd +1 L + S even • P = (-1)L+1 • C and P are broken by Cabibbo and CKM matrix

  7. CP Violation • Combination of C and P symmetry • CP is only broken by CKM matrix, not Cabibbo matrix • Standard Model predicts CP violation in addition to the 9 decays seen in CKM

  8. Discovery of Upsilon • Upsilon meson • In 1977 by Leon Lederman and team of physicists • Fermilab particle accelerator enables collision of proton and antiproton with an energy of 1.96 TeV at the DZero and CDF detectors • For every 100 billion collisions that occur, one upsilon with mass of 9.5 GeV is produced

  9. Fermilab Particle Accelerator

  10. Upsilon Meson • Meson containing bottom and antibottom • Upsilon (S1) mass of 9.44 +/- 0.03 and Upsilon (S2) mass 10.17 +/- 0.05 GeV • 1.21×10−20 seconds • Decays into charm, • S = 1 or 0 • L = 0 • Four excited states discovered

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