the asymmetry between matter and antimatter
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
The Asymmetry between Matter and
Antimatter
Besma M’charekFEW, Vrije Universiteit Amsterdam
The asymmetry between matter and antimatter
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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
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Matterq
uark
sele
ctronNucleusneutron
proton
atom
Matter/antiMatter
The asymmetry between matter and antimatter
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“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
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Where is the antimatter?
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EM
EW
Where is the antimatter?
life
13.7 billion y
1st stars
1 billion y
3000K
300,000 y
H/He
300 s106 s1011 s
matter +antimatter
< 1011 sA
atom
nucleushadrons
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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 +
•Charge Parity symmetry:•Changes a particle into its antiparticle.
=>In weak interactions, parity symmetry is always violated
=>In weak interactions, charge symmetry is always violated
=>In weak interactions, CP is almost never violatedalmost
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P
P
C C
Escher on CP violation…
CP
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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
photon
ge
gubeiγ
u
b
Weak interactions
Electromagnetic interactions
W+
ie
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B-mesons in the LHCb detector •B-mesons mix to:
•In the LHCb detector, we want to study weak interaction with the special B-decays:
Two quarks, one is
always a b-quarkB-
mesons
B
s s
s s
s s
s s
B D K
B D K
B D K
B D K
B B
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CERN
4.4 km
1989-2000 LEP e+e (88-209 GeV)2007-2015 LHC pp (14000 GeV)
LHCb
Atlas
Alice
CMS
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The LHCb detector
The detector
Results
Simulation and Reconstruction
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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
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Additional slides!!!
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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
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The CKM-matrix and the γ-parameter
• The mixing of quarks in weak interactions is described by the CKM-matrix.
• The complex Vxy entries of the matrix are the nine gw parameters.
• 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. .
ud us ub
cd cs cb
td ts tb
V V V
V V V
V V V
iub
it
ud us
cd cs cb
ts tbd
V e
V e
V V
V V V
V V
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Proposed project
• Improving the reconstruction program
• Developing the selection procedure of the Bs->DsK events
• Developing the fitting method in order to obtain the γ-parameter from the selected events