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The Asymmetry between Matter and Antimatter

The Asymmetry between Matter and Antimatter. Besma M’charek FEW, Vrije Universiteit Amsterdam. Outline. The Standard Model of Physics and asymmetry between matter and antimatter Charge Parity (CP) violation. Measuring CP violation with the LHCb detector at CERN Geneva. Summary.

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The Asymmetry between Matter and Antimatter

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  1. The Asymmetry between Matter and Antimatter Besma M’charek FEW, Vrije Universiteit Amsterdam

  2. Outline • The Standard Model of Physics and asymmetry between matter and antimatter • Charge Parity (CP) violation. • Measuring CP violation with the LHCb detector at CERN Geneva. • Summary. “Matter /antimatter asymmetry” The asymmetry between matter and antimatter

  3. atom Matter Matter/antiMatter quarks electron Nucleus neutron proton The asymmetry between matter and antimatter

  4. “The Standard Model” • The fundamental building block of matter consists of: 6 quarks (u, d, c, s, t, b) 6 leptons(e,μ,τ,νe,νμ,ντ). • These particles interact through four difference forces: • electromagnetic • strong forces • weak forces • gravity The asymmetry between matter and antimatter

  5. Where is the antimatter? The asymmetry between matter and antimatter

  6. Where is the antimatter? < 1011 sA 1011 s 106 s 300 s 300,000 y 1billion y 13.7 billion y 3000K matter + antimatter H/He 1st stars life EM EW hadrons nucleus atom The asymmetry between matter and antimatter

  7. Charge Parity symmetry • Parity symmetry : • Parity P reflects a system into its mirror-image • What if your image behaves differently than you?? • Charge symmetry: • Charge conjugation C changes the electric charge of the particle. • e +e - • K -K + =>In weak interactions, charge symmetry is always violated =>In weak interactions, paritysymmetry is always violated • Charge Parity symmetry: • Changes a particle into its antiparticle. =>In weak interactions, CP is almostnever violated almost The asymmetry between matter and antimatter

  8. Escher on CP violation… P CP C C P The asymmetry between matter and antimatter

  9. photon ge u gubeiγ b Weak interactions A main difference between electromagnetic and weak interactions is in the coupling constants ge and gubeiγ , .. • 1 for the electromagnetic • 9 for the weak • Weak interactions can change quark flavors ( e.g.: from up u to bottom b). • Mixing of quarks Electromagnetic interactions W+ Weak interactions The asymmetry between matter and antimatter

  10. B-mesons in the LHCb detector • B-mesonsmix to: • In the LHCb detector, we want to study weak interaction with the special B-decays: Two quarks, one is always a b-quark B-mesons The asymmetry between matter and antimatter

  11. CERN 1989-2000 LEP e+e (88-209 GeV) 2007-2015 LHC pp (14000 GeV) LHCb  4.4 km CMS Atlas Alice The asymmetry between matter and antimatter

  12. The LHCb detector The detector Results Simulation and Reconstruction The asymmetry between matter and antimatter

  13. Summary • In the universe, there is an asymmetry between matter and antimatter. • We need CP-symmetry breaking in order to explain this asymmetry. • We will use the LHCb detector and study the decay of B-mesons (abundant in this detector). • We will measure the parameter γ The asymmetry between matter and antimatter

  14. Additional slides!!! The asymmetry between matter and antimatter

  15. History of our universe • First the universe was hot and compact: a soup of energetic photons and massive particles. • The laws of physics allow a sufficiently energetic photon to create a particle/antiparticle pair and a particle/antiparticle pair can annihilate into an energetic photon. • Annihilation and Creation happened continuously =>There was an equal amount of matter and anitmatter The asymmetry between matter and antimatter

  16. The mixing of quarks in weak interactions is described by the CKM-matrix. The complex Vxy entries of the matrix are the ninegwparameters. The matrix can be written in a way that only two entries are left complex arguments. The arguments of those two entries are measurable. We want to measure one of these entries. . The CKM-matrix and the γ-parameter The asymmetry between matter and antimatter

  17. Proposed project • Improvingthe reconstruction program • Developingthe selection procedure of the Bs->DsK events • Developingthe fitting method in order to obtain the γ-parameter from the selected events The asymmetry between matter and antimatter

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