Flavour%20Physics%20and%20Dark%20Matter

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Flavour Physics and Dark Matter

• Introduction
• Selected Experimental Results
• Impact on Dark Matter Searches
• Conclusion

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Why Beyond Standard Model?

• Standard Model predictions validated to high
  precision, however

• Gravity not a part of the SM
• What is the very high energy behaviour?
• At the beginning of the universe?
• Dark Matter?
• Astronomical observations of indicate that there
  is more matter than we see
• Where is the Antimatter?
• Why is the observed universe mostly matter?

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Searches For New Physics

• How do you search for new physics at a collider?
• Direct searches for production of new particles
• Particle-antipartical annihilation top quark
• Indirect searches for evidence of new particles
• Within a complex process new particles can occur
  virtually

• Tevatron is at the energy frontier
• Tevatron and b factories are at a data volume
  frontier
• billions B and Charm events on tape
• So much data that we can look for some very
  unusual processes
• Where to look
• Many weak processes involving B hadrons are very
  low probability
• Look for contributions from other low probability
  processes Non Standard Model

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B Physics Beyond the SM

• Look at processes that are suppressed in the SM
• Excellent place to spot small contributions from
  non SM contributions
• The Main Players
• Bs(d) ? µµ-
• SM No tree level decay
• b ? s?
• Penguin decay
• New Players
• Bs Oscillations
• B ? ??

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The B Factories
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b ? s?

• Look at decays that are suppressed in the
• Standard Model b ? s?
• Classic b channel for searching for new physics
• Inclusive decay easier to calculate but still
  difficult
• New physics can enter into the loop(penquin)
• Decay observed
• Now a matter of precision
  measurement and precision
  calculation of the SM rate
• New calculation by Misiak et. al.
• NNLO calucation - 17 authors
  and 3 years of effort
• BR(b ? s?) 3.15 ? 0.23 x 10-4

PRL 98 022002 2007
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b ? s?

• Measure the inclusive branching ratio from the
  photon spectrum
• Backgrounds from continuum production and other B
  decays
• Continuum backgrounds suppressed using event
  shapes or reconstruction the other B
• ?o and ? reconstructed and suppressed

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Bs(d) ? µµ-

• Look at decays that are suppressed in the
• Standard Model Bs(d) ? µµ-
• Flavor changing neutral currents(FCNC) to leptons
• No tree level decay in SM
• Loop level transitions suppressed
• CKM , GIM and helicity(ml/mb) suppressed
• SM BF(Bs(d) ? µµ-) 3.5x10-9(1.0x10-10)
• G. Buchalla, A. Buras, Nucl. Phys. B398,285
• New physics possibilities
• Loop MSSM mSugra, Higgs Doublet
• 3 orders of magnitude enhancement
• Rate ?tan6ß/(MA)4
• Babu and Kolda, Phys. Rev. Lett. 84, 228
• Tree R-Parity violating SUSY
• Small theoretical uncertainties. Easy to spot
  new physics

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Bs(d) ? µµ- Method

• Relative normalization search
• Measure the rate of Bs(d) ? µµ- decays relative
  to B ?J/?K
• Apply same sample selection criteria
• Systematic uncertainties will cancel out in the
  ratios of the normalization
• Example muon trigger efficiency same for J/? or
  Bs ?s for a given pT

400pb-1
N(B)2225
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Discriminating Variables

• Mass Mmm
• CDF 2.5s window s 25MeV/c2
• DØ 2s window s 90MeV/c2
• CDF ?ct/ctBs, DØ Lxy/?Lxy
• ?a fB fvtx in 3D
• Isolation pTB/( ?trk pTB)
• CDF, ?, ?a and Iso used in
  likelihood ratio
• D0 additionally uses B and ? impact parameters
  and vertex probability
• Unbiased optimization
• Based on simulated signal and data sidebands

• 4 primary discriminating variables

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Bs(d) ? µµ- Search Results

• CDF Result 1(2) Bs(d) candidates observed
  consistent with background expectation

Decay Total Expected Background Observed
CDF Bs 1.27 0.36 1
CDF Bd 2.45 0.39 2
D0 Bs 0.8 0.2 1.5 0.3 3

• D0 Result First 2fb-1 analysis!

• Combined

• CDF 1 Bs result 3.0?10-6

PRD 57, 3811 1998
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Bs ? µµ- Physics Reach

• Excluded at 95 CL (CDF result only)
• BF(Bs ? ??- ) 1.0x10-7
• Dark matter constraints

L. Roszkowski et al. JHEP 0509 2005 029

• Strongly limits specific SUSY models SUSY SO(10)
  models
• Allows for massive neutrino
• Incorporates dark matter results

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B Physics and Dark Matter

• B Physics constraints impact dark matter in two
  ways
• Dark matter annihilation rates
• Interesting for indirect detection experiments
• Annihilation of neutralinos
• Dark matter scattering cross sections
• Interesting for direct detection experiments
• Nucleon neutralino scattering cross sections
• Models are (n,c)MSSM models with constraints to
  simplify the parameter space Key parameters
  are tanß and MA as in the flavour sector along
  with m1/2
• Two typical programs of analysis are performed
• Calculation of a specific property Nucleon
  neutralino scattering cross sections
• Constraints from Bs(d) ? µµ- and b ? s? as well
  as g-2, lower bounds on the Higgs mass, precision
  electroweak data, and the measured dark matter
  density.
• General scan of allowed SUSY parameter space from
  which ranges of allowed values can be extracted

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SUSY and Dark Matter

• Whats consistent with the constraints?
• There are various areas of SUSY parameter space
  that are allowed by flavour, precision
  electroweak and WMAP
• Stau co-annihilation
• Funnel
• Bulk Region
• Low m0 and m1/2, good for LHC
• Focus Point
• Large m0 neutralino becomes higgsino like
• Enhanced Higgs exchange scattering diagrams
• Disfavoured by g-2, but g-2 data is controversial

H. Baer et. al.
TeV
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Flavour Constraints on m?

• New analysis uses all available flavour
  constraints
• Bs ? µµ-, b ? s?,Bs Oscillations, B ? ??
• Later two results only 1 year old
• CMSSM - constrained so that
  SUSY scalers and the Higgs
  and the gauginos have a
  common mass at the GUT scale
  m0 and m1/2 respectively

J. Ellis, S. Heinemeyer, K. Olive, A.M Weber and
G. Weiglein hep-ph/0706.0652
Focus Point
Stau co-annihilation
This region favoured because of g-2
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Bs ? µµ- and Dark Matter

• Bs ? µµ- correlated to dark matter searches
• CMSSM supergravity model
• Bs ? µµ- and neutralino scattering cross
  sections are both a strong functions of tanß
• In high tanß(tanß 50), positive µ, CDM allowed
• Current bounds on Bs ? µµ- exclude parts of
  
  the parameter space for direct dark
  matter detection

S. Baek, D.G. Cerdeno Y.G. Kim, P. Ko, C. Munoz,
JHEP 0506 017, 2005
R. Austri, R. Trotta, L. Roszkowski,
hep-ph/0705.2012
More general scan in m0, m1/2 and A0, allowed
region
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B Physics and Dark Matter

• Putting everything together including most recent
  theory work on b ? s?

• Analysis shows a preference for the Focus Point
  region, g-2 deweighted
• Higgsino component of Neutralino is enhanced.
• Enhances dominant Higgs exchange scattering
  diagrams
• Interesting relative to light Higgs searches at
  Tevatron and LHC
• Probability in some regions has gone
  down

R. Austri, R. Trotta, L. Roszkowski,
hep-ph/0705.2012
S. Baek, et.al.JHEP 0506 017, 2005
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Current Xenon 10 Results

• Liquid Xenon detector
• Multiple modules

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Dark Matter Prospects

• From dmtools.brown.edu
• Just considering upgrades of the two best current
  experiments and LUX.
• Prospects for dark matter detection look good in
  CMSSM models constrained by collider data!

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Conclusions

• Collider experiments are providing a wealth of
  data on Flavour physics as well as direct
  searches and precision electroweak data
• These data can be used to constrain the masses
  and scattering cross sections of dark matter
  candidates
• Constrained MSSM models indicate that dark matter
  observation may be within reach for current or
  next generation experiments! If Bs ? µµ- is
  there as well.

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