Session on LFV and rare D and B decays

This twiki page documents the discussion of LFV and rare B and D decays for the LHCb-Theory workshop in November 2011.

Session organisation

A preliminary agenda for the session is:

Talk Description Speaker
Introduction (5 min) Brief introduction of the session  
Interplay between direct and indirect searches (30 min ) Summary of interplay between direct and indirect search results, including results from global fits  
Constraints on Wilson coefficients from global fits (20 min) Overview of the constraints on C7, C9, C10 coming from global fits of radiative Bd decays and Bd -> K* mu mu. What measurements can we include to improve sensitivity to NP.  
LHCb summary: Prospects for Bd -> K* mu mu, Bd -> K* gamma and related channels (20 min) Overview of LHCb prospects for Winter conferences and 2012  
Observables in b -> s (d) mu mu and b -> s (d) gamma decays (20 min) What new observables can we add? What do large Isospin asymmetries tell us about NP? CP violation in rare decays?  
Coffee and discussion (30 min)  
LHCb summary: reach in rare decay searches (20 min) Summary of LHCb's sensitivity in rare decay searches for Winter conferences and 2012  
Searches with non-LFV channels (30 min) Prospects for D0 -> mu mu, Bs(d) -> mu mu (and tau tau). Correlations between rare decay searches and mixing in B and Charm  
LFV searches (30 min) Review of LFV tau decays after MEG. What are the correlations between charged and photon modes? What are the correlations between LFV tau decays and searches for non-LFV B and D decays.  

List of questions:

  • General topics for discussion are:
    • The interplay between the various Rare Decays measurements and measurements of CPV in the B and Charm system.
      • What does the excess in B->tau nu tell us about BR Bsmumu and other rare decays?
    • Measurements with tau decays (this is an area that LHCb is not yet heavily pursuing).

  • Bs -> mu mu:
    • Given the current limits on Bs --> mu mu, what are the prospects on Bs --> tau tau, D0 --> mu mu , and related channels in MFV and non-MFV models?
    • SM calculation of BR(Bs-->mumu): Summarize SM calculation with the different approaches used. Is there a preferred calculation? Suggest a values and publication as SM reference.

  • b --> s l+ l-
    • What are the prospects for measurements of Bd --> K* tau tau? Are new observables accessible with tau reconstruction (helicity of the lepton)?
    • Assuming Bd -> K* mu mu is SM like, what are the prospects with Bs --> phi mu mu and Lambda_b --> lambda mu mu? Can there be large deviations in b --> d mu+ mu- channels where SM is further suppressed?
    • Can you see large direct CP asymmetries in Bd --> K* mu mu? Are there constraints from non-rare decays that limit the size of the CP violation?
    • Is a large, Babar-like, Isospin asymmetry possible in any class of NP models (whilst remaining consistent with A_I( K* gamma))?

  • Radiative decays:
    • What are the constraints from b -> d gamma decays? And what can learn from b->d gamma? Do we gain by measuring these suppressed modes versus measurements of b -> s gamma?

  • LFV
    • Given existing results on mu -> e gamma and mu -> 3 e, what are the prospects for tau -> 3 mu?
    • What are the most promising decays to search for lepton flavour violation that can be measured in LHCb (which could include final states with electrons, muons, taus or charged hadrons, e.g. B -> e mu)?
    • What are the correlations with other non-lepton flavour violating observables (e.g. Bs -> mu mu)?
  • B-->4mu, other decays
    • B-->4mu is experimentaly rather background free. Can it be used to constrain NP (e.g., look for Z' w/o contradicting Bs mixing, look for new scalars ...)
    • Can be this (or other channel) be related to HyperCP Sigma ->p mumu (H.Park et al. (HyperCP Coll.) PRL 94, 021801 (2005))

April 16th - 18th Session organisation for Rare Decays

April 16th and 17th 11:15-13:00


April 18th 09:00-10:45

-- ThomasBlake - 10-Oct-2011

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Topic revision: r5 - 2012-03-05 - ThomasBlake
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