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Flavour Physics and Dark Matter

Flavour Physics and Dark Matter. Matthew Herndon University of Wisconsin Dark Side of the Universe 2007, Minneapolis Minnesota. Introduction Selected Experimental Results Impact on Dark Matter Searches Conclusion. Why Beyond Standard Model?.

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Flavour Physics and Dark Matter

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  1. Flavour Physics and Dark Matter Matthew Herndon University of Wisconsin Dark Side of the Universe 2007, Minneapolis Minnesota • Introduction • Selected Experimental Results • Impact on Dark Matter Searches • Conclusion

  2. Why Beyond Standard Model? Standard Model fails to answer many fundamental questions Many of those questions come from Astrophysics and Cosmology Connection between collider based physics and astrophysics becomes more interesting each year • 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? DSU 2007 M. Herndon 2

  3. Searches For New Physics Rare Decays, CP Violating Decays and Processes such as Mixing Present unique opportunity to find 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 DSU 2007 M. Herndon 3

  4. B Physics Beyond the SM Same particles/vertices occur in both B decay diagrams and in dark matter scattering or annihilation diagrams • Look at processes that are suppressed in the SM • Excellent place to spot small contributions from non SM contributions • The Main Players: • Bs(d)→μ+μ- • SM: No tree level decay • b s • Penguin decay • New Players • Bs Oscillations • B  M. Herndon 4

  5. The B Factories EXCELLENT MUON DETECTION EXCELLENT PARTICLE ID EXCELLENT TRACKING: TIME RESOLUTION CDF D0 BABAR BELLE 5

  6. b → s One of the best indirect search channels at the b factrories • 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 DSU 2007 M. Herndon 6

  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)→ μ+μ- One of the best indirect search channels at the Tevatron • Look at decays that are suppressed in the Standard Model: Bs(d)→μ+μ- • 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)→μ+μ-) = 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 tan6β/(MA)4 Babu and Kolda, Phys. Rev. Lett. 84, 228 • Tree: R-Parity violating SUSY • Small theoretical uncertainties. Easy to spot new physics DSU 2007 M. Herndon 8

  9. Bs(d)→ μ+μ-Method 9.8 X 107B+ events • Relative normalization search • Measure the rate of Bs(d)→ μ+μ-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 DSU 2007 M. Herndon 9

  10. Discriminating Variables 4 primary discriminating variables • Mass Mmm • CDF: 2.5σwindow:σ = 25MeV/c2 • DØ: 2σwindow:σ = 90MeV/c2 • CDF λ=cτ/cτBs, DØ Lxy/Lxy • α : |φB – φvtx| in 3D • Isolation: pTB/( trk + pTB) • CDF, λ, α 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 DSU 2007 M. Herndon 10

  11. Bs(d)→ μ+μ-SearchResults Worlds Best Limits! BF(Bs +- ) < 10.0x10-8 at 95% CL BF(Bd +- ) < 3.0x10-8 at 95% CL BF(Bs +- ) < 9.3x10-8 at 95% CL BF(Bs +- ) < 5.8x10-8 at 95% CL CDF Result: 1(2) Bs(d)candidates observedconsistent with background expectation D0 Result: First 2fb-1 analysis! Combined: CDF 1 Bs result: 3.010-6 PRD 57, 3811 1998 M. Herndon 11

  12. Bs→ μ+μ-:Physics Reach A close shave for the theorists Typical example of SUSY Constraints However, large amount of recent work specifically on dark matter BF(Bs +- ) < 5.8x10-8 at 95% CL • Excluded at 95% CL (CDF result only) • BF(Bs +- ) = 1.0x10-7 • Dark matter constraints • Strongly limits specific SUSY models: SUSY SO(10) models • Allows for massive neutrino • Incorporates dark matter results L. Roszkowski et al. JHEP 0509 2005 029 DSU 2007 12

  13. B Physics and Dark Matter Results can then be compared to experimental sensitivities • 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 tanβ 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)→μ+μ- 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 DSU 2007 M. Herndon 13

  14. SUSY and Dark Matter Informs you about what types of dark matter Interactions are interesting • What’s 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 M. Herndon 14

  15. Flavour Constraints on m ~ Definite preferred neutralino masses • New analysis uses all available flavour constraints • Bs→μ+μ-, 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 M. Herndon 15

  16. Bs→ μ+μ- and Dark Matter • Bs→μ+μ- correlated to dark matter searches • CMSSM supergravity model • Bs→μ+μ- and neutralino scattering cross sections are both a strong functions of tanβ • In high tanβ(tanβ ~ 50), positive μ, CDM allowed • Current bounds on Bs→μ+μ-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 CDF Paper Seminar 2007 M. Herndon 16

  17. B Physics and Dark Matter Current experiments starting to probe interesting regions However… • 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 • Putting everything together including most recent theory work on b s R. Austri, R. Trotta, L. Roszkowski, hep-ph/0705.2012 S. Baek, et.al.JHEP 0506 017, 2005 DSU 2007 M. Herndon 17

  18. Current Xenon 10 Results Excluded by newBs→μ+μ- • Excluding part of the high probability region - 60 live day run! Xenon 10 Preliminary R. Austri, R. Trotta, L. Roszkowski Current best limits • Liquid Xenon detector • Multiple modules M. Herndon 18

  19. Dark Matter Prospects Excluded by new Bs→μ+μ- Perhaps find both Dark Matter and Bs→ μ+μ- • 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! DSU 2007 M. Herndon 19

  20. Conclusions A simulations observation of direct(or indirect) evidence for new physics at a collider and Cold Dark Matter would reveal much about the form of the new physics • 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→μ+μ- is there as well. DSU 2007 M. Herndon 20

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