Quarks Flashcards
How is charge written in terms of isospin & hypercharge?
What is the equation for hypercharge?
How do the following symmetry operators act on the following quantum numbers?
How are CP eigenstates defined (using mesons as an example)?
What is the table of existing mesons relative to quark content?
How do the Cabibbo & CKM mixing matrices act on quarks?
How does the Wolfenstein parameterisation of the CKM matrix appear (up to 3rd order)?
Draw the two box diagrams that cause meson mixing, using neutral kaons as an example.
How do we define meson mass eigenstates?
State the condition for CP violation in mixing.
What is the function responsible for meson mixing?
Define all terms in the function.
What is the condition for meson mixing to occur?
For meson mixing to occur, either (x) or (y) must be non-zero.
What are the following probabilities of meson mixing occuring, in terms of the meson mixing function?
What are the following meson average lifetimes?
What is the asymmetry term for CP violation in decays (in terms of both decay channels and the strong & weak phases)?
What are the decay amplitudes in terms of the leading-order and suppressed amplitudes?
(HINT: define the ratio, strong & weak phases).
What diagram represents the impact parameter used in heavy flavour tagging?
What diagram represents B-tagging, and what do we measure in opposite/same-side tagging?
- Opposite : follow the b-charge as it decays in leptons or kaons, then trace back to find the root
-
Same-side : Search for flavour pairs (e.g. u and ū).
Note : neutral B-mesons can oscillate & produce false tagging.
What are tree-level colour allowed & supressed decay diagrams (use the neutral D-meson as an example)?
What is a W-exchange diagram (use netural D-meson decay as an example)?
The leading order diagram where both quarks change flavour.
What is a gluonic penguin diagram (use neutral D-meson decay as an example)?
A decay with a W-loop and gluon pair production.
What is an electromagentic penguin diagram (use neutral D-meson decay as an example)?
Contains a W-loop and photon/Z-boson pair production.
What is a meson annihilation diagram?
Note: heavily colour suppressed.
What is the systematic uncertainty mitigation for CP amplitudes?
What is the Dalitz plot for finding mass pairs?
It tells you the masses of resonances in decays
How do we measure CP violating mixing asymmetrys?
What variable do we use evaluate CP violation in the interference of mixing & decays?
How does the CP violating interference variable tell us if & where we have CP violations?
Construct an example of a unitary triangle from the following unitary relation.
What is direct & indirect CP violation?
- Direct Occurs when the decay isn’t equal to the decay of the CP conjugate.
- Indirect Occurs when they have the same decay channels, but in different rates (and can mix)
How many parameters are there in a NxN mixing matrix?
What is the mixing probability graph for neutral kaons?
What is the mixing probability graph for neutral D-mesons?
What is the mixing probability graph for neutral B-mesons?
What is the mixing probability graph of neutral B_s mesons?
What are the main differences in methods & purities of flavour tagging of neutral D & B-mesons?
D-mesons
- Strong decays can be fully reconstructed
- Weak decays have high backgrounds, can be partially reconstructed
- Shirt lifetimes & slow oscillations, so we need high precisions.
B-meson
- Longer lifetimes,so we can track their paths & find 2nd vertices. Better precision.
- Opposite & same-side tagging lets use follow flavours/charges to reconstruct vertices.
For purities, think about distinguishing from the backgrounds.
How do you tell the spin of particles in a Dalitz plot?
Looking at how many gaps are in the resonance.
Name three sources of fake CP asymmetries in meson decays.
- Production Heavy quarks get swallowed up by baryons.
- B-field Opposite charges are sent to different detectors with different efficiencies
- Interaction Different mesons & decay products have different cross-sections with detectors
Draw two examples (flavour & charge) of D-meson tagging.
What are the three stages of event selection for flavour experiments?
- Select candidates via kinematics.
- Identify possible decay product combinations.
- Further selection criteria (flight distance, points of origin)
What is required for asymmetries in decays, in terms of the strong & weak phases ans the amplitudes? What is the approximate asymmetry for decay?
We require multiple decay amplitudes with different strong & weak phases.
What is the PDG parameterisation of the CKM matrix?
