Flavour%20Physics%20and%20Dark%20Matter - PowerPoint PPT Presentation

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

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Flavour Physics and Dark Matter Introduction Selected Experimental Results Impact on Dark Matter Searches Conclusion Matthew Herndon University of Wisconsin – PowerPoint PPT presentation

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Title: Flavour%20Physics%20and%20Dark%20Matter


1
Flavour Physics and Dark Matter
  • Introduction
  • Selected Experimental Results
  • Impact on Dark Matter Searches
  • Conclusion

2
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?

2
M. Herndon
DSU 2007
3
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

3
M. Herndon
DSU 2007
4
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 ? ??

4
M. Herndon
5
The B Factories
5
6
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
6
M. Herndon
DSU 2007
7
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

7
8
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

8
M. Herndon
DSU 2007
9
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
9
M. Herndon
DSU 2007
10
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

10
M. Herndon
DSU 2007
11
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
11
M. Herndon
12
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

12
DSU 2007
13
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

13
M. Herndon
DSU 2007
14
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
14
M. Herndon
15
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
15
M. Herndon
16
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
16
M. Herndon
CDF Paper Seminar 2007
17
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
17
M. Herndon
DSU 2007
18
Current Xenon 10 Results
  • Liquid Xenon detector
  • Multiple modules

18
M. Herndon
19
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!

19
M. Herndon
DSU 2007
20
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.

20
M. Herndon
DSU 2007
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