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Probing the Connection Between Supersymmetry and Dark Matter

Probing the Connection Between Supersymmetry and Dark Matter. Bhaskar Dutta University of Regina, Canada. Physics Colloquium, TAMU, January 27, 2005. My Research Pie. TALK OUTLINE. B Decays

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Probing the Connection Between Supersymmetry and Dark Matter

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  1. Probing the Connection Between Supersymmetryand Dark Matter Bhaskar Dutta University of Regina, Canada Physics Colloquium, TAMU, January 27, 2005

  2. My Research Pie TALK OUTLINE • B Decays • B. Dutta, C.S. Kim, and S. Oh, PRL 90, 011801 (2003) … Anomalies in B0f KS and B+h' K+ Decays • CP • K.S. Babu, B. Dutta, and R.N. Mohapatra, PRD 65, 016005 (2001) … Strong CP and the SUSY Phase Problems • K.S. Babu, B. Dutta, and R.N. Mohapatra, PRL 85, 5064 (2000) … Electric Dipole Moment of the Muon with Large Neutrino Mixing • Neutrinos • B. Dutta, Y. Mimura, and R.N. Mohapatra, PRD 69, 115014 (2004) … CP Violation in SO(10) Model for Neutrinos • String Models and Phenomenology • R. Arnowitt, J. Dent, and B. Dutta, PRD 70, 126001 (2004) … Five Dimensional Cosmology in Horava-Witten M-Theory

  3. My Research Pie TALK OUTLINE • Dark Matter • R. Arnowitt, B. Dutta, and Y. Santoso, NP B606,  59 (2001) … Coannihilation Effects in Supergravity and D-Brane Models • Collider Physics • B. Dutta, R.N. Mohapatra and  D.J. Muller, PRD 60, (1999) 095005 … Doubly Charged Higgsino of SUSY Left-Right Models at the Tevatron • R. Arnowitt, B. Dutta, T. Kamon, and M. Tanaka, PLB 538, 121 (2002) … Detection of Bsm+m- at the Tevatron Run II and Constraints of the SUSY Parameter Space

  4. TALK OUTLINE • Today’s Talk • Recent works on “Collider Physics” and “Dark Matter Physics.” • Introduction to Standard Model (SM) • Reasons for going beyond the SM • Supersymmetric (SUSY) SM • Existing experimental constraints • Prospects of discovering SUSY in the future dark matter experiments • Prospects of discovering SUSY in the future Linear Collider (LC) and Large Hadron Collider (LHC) • Conclusion

  5. http://www.damtp.cam.ac.uk/user/gr/public/bb_history.html t t = 14 billion years 500 M yrs Galaxy Formation Relic Radiation Decouples: WMAP 1 s 10-7s SUSY Relic 10-11s 10-43s Quantum Gravity

  6. Road Map to Unified Theory E String Theory SUSY GUT x

  7. Standard Model (SM) Glashow ’62, Weinberg ’67, Salam ’68 Underlying theory: a gauge theory (e.g., QED) Quantum Mechanics + Special Relativity 6 quarks, 6 leptons and gauge particles How can we see them?

  8. One way to see quarks and leptons “Quarks. Neutrons. Mesons. All those particles You can’t see. That’s what drove me to drink. But now I can see them!”

  9. Real way to see Top (or Heavy Particles)

  10. _ Standard Model

  11. Too Heavy t and Non-Zero n QUARK MASSES Yet to be discovered h NEUTRINO MASSES Neutrino masses are non zero! The SM can not accommodate nonzero neutrino mass!!! See recent results from SuperKamiokande, SNO, KamLAND, K2K, MACRO (Webb et al.). For future results, see MINOS (Webb et al.), MiniBoone, T2K, …

  12. Beyond the SM The SM works very well at ~100 GeV. Three gauge couplings do not meet at a single point. (Strength of Force)-1 But we want to build a theory which goes to a higher scale. Grand Unified Theory

  13. Structural Defect in the SM • Problem • The Higgs mass becomes too large at scale of a few TeV (1000 xMproton). • There should be some new theory at this energy scale and this theory would keep the Higgs mass under control. The contribution to the Higgs mass Boson loop Fermion loop L= Scale of new physics

  14. Structural Defect in the SM • Possible Solutions (= New Physics) • Technicolor: Higgs is not a fundamental particle. Experimental data do not allow this theory any more. It only exists in a movie entertainment world. • Extra dimension (ED) at (~)TeV scale. EDs appear at around TeV scale. These theories are not well developed to have clear predictions. • Supersymmetric SM

  15. Supersymmetric SM • The fundamental law(s) of nature is hypothesized to be symmetric between bosons and fermions. • Fermion (S = ½ ) Boson (S = 0 or 1) • Have they been observed? • ➩ Not yet. ☹

  16. Feynman Diagrams for SUSY Supersymmetric partner of W boson Supersymmetric partner of Z boson Lightest neutralinos are always in the final state! This neutralino is the dark matter candidate!! What do we gain if the theory is supersymmetric?

  17. Supersymmetric Unification • Grand Unified Picture! • Higgs mass does not become large at any scale. • The top quark mass is predicted to be 150 to 200 GeV. D0 and CDF measured: • Mtop = 178  4 GeV MSUSY~TeV

  18. Supersymmetry: Elegant Solution Many new particles (100 GeV – a few TeV) and many new parameters. Whatever happened to elegant solutions?

  19. Minimal Supergravity Model • SUSY model with two Higgs fields in the framework of unification: • All SUSY masses are unified at the grand unified scale. 2) Two more parameters: A0 tanb <H1> , <H2> <H> , tanb

  20. CDM = Neutralino ( ) Probing the Crucial Connection Astrophysics CDM = The matter which is present without any electromagnetic interaction. To explain the amount of the CDM, there must be another SUSY particle whose mass must be closer to the neutralino. Is it possible to observe these features in other experiments? Dark matter detection? Collider experiments? SUSY

  21. Existing Bounds from Experiments • [1] Higgs Mass (Mh): • 114 GeV < Mh < 130 GeV • (The Higgs mass depends on the mass parameters m0 and m1/2, and A0 and tanb.) • [2] Branching Ratio bsg: • CLEO: (3.21  0.47) x 10-4 • SM : (3.62  0.33) x 10-4 • Excluding parameter space based on the SUSY particle masses.

  22. Excluded Region in SUSY World Excluded Mass of Squarks and Sleptons Mass of Gauginos

  23. Existing Bounds from Experiments [3] Magnetic Moment of Muon:

  24. Excluded Region in SUSY World Excluded Mass of Squarks and Sleptons Mass of Gauginos

  25. Existing Bounds from Experiments [4] Dark Matter: Allowed region • The relic density is expressed as W where WCDM = 0.23  0.04. • Neutralino ( ) constitutes the dark matter in this model. It is the lightest and stable particle in our model. • In order to calculate WCDM, we need to know the density of the remaining neutralinos when they stopped annihilating each other, “neutralino annihilation,” i.e. • WCDM • WCDM can be expressed in terms of our mSUGRA parameters.

  26. Co-annihilation [Griest and Seckel ’92]: An accidental near degeneracy occurs naturally for light stau in mSUGRA. • Here . This diagram also contributes to the relic density along with the other neutralino annihilation diagrams.This is a generic feature of any SUSY model. • Other regions (focus point, annihilation funnel): mostly beyond the LHC – But, can be observed at a possible energy upgrade of the LHC- Tripler. P. McIntyre, Proceedings of DARK2004

  27. Excluded Region in SUSY World Allowed region Excluded Mass of Squarks and Sleptons Mass of Gauginos

  28. Small tanb Region narrow co-annihilation corridor Mass of Squarks and Sleptons Mass of Gauginos

  29. Large tanb Region narrow co-annihilation corridor R. Arnowitt, B.D., T. Kamon, M. Tanaka, Phys. Lett. B538, 121 (2002) R. Arnowitt, B.D., B. Hu, hep-ph/0310103 (talk at BEYOND '03) A. Lahanas, D.V. Nanopoulos, Phys. Lett. B568, 55 (2003) J. Ellis et al., Phys. Lett. B565,176 (2003) H. Baer et al., JHEP 0207, 050 (2002)

  30. nucleus recoil Dark Matter Experiments • The neutralinos can be detected in the dark matter detectors by scattering: • This recoil can be detected in various ways such as ionization and scintillation. • The existence of SUSY in the nature can be proved in these experiments. R. Arnowitt, B.D. Y. Santoso, B.Hu, Phys. Lett. B505, 177 (2001) J. Ellis, D. Nanopoulos, K. Olive, Phys. Lett. B508, 65, (2001) H. Baer et al., JCAP 0309, 007 (2003)

  31. Various ongoing experiments such as • DAMA group (Italy) – claiming to have observed some events. • CDMS (USA) group – disputing their claim. • Ongoing/future projects: ZEPLIN, GENIUS, Cryoarray, CUORE etc. Edelweiss DAMA 10-6pb CDMS J. White et al., Proceedings of DARK2004

  32. Neutralino-Proton Cross Section 1-2 order of magnitude below the current experimental sensitivity

  33. Collider Experiments • Questions: • What are the signals from the narrow co-annihilation corridor?

  34. Collider Experiments • Questions: • What are the signals from the narrow co-annihilation corridor? • What is the accuracy of the measurement on DM? • Collider Experiments: • Tevatron (2 TeV ) • LHC (14 TeV ) • LC (500 or 800 GeV e+e–) • The reach of the Tevatron is not high enough. • We will first discuss the LC since it measures the mass very accurately. V. Krutelyov, R. Arnowitt, B.D., T. Kamon, P. McIntyre, Y. Santoso, Phys. Lett. B505, 161 (2001); R. Arnowitt, B.D., T. Kamon, M. Tanaka, Phys. Lett. B538, 121 (2002)

  35. Study of SUSY Signals at LC Kinematical limits • Develop event selection cuts and extract signal from the background • Discovery significance of the parameter space • DM = Accuracy of measuring the most crucial parameter

  36. SUSY Signals at LC • Stau-pair production • Neutralino-pair production E(t ) is small because DM is small.

  37. SM Backgrounds at LC • 4-fermion WW, ZZ, Znn production • e.g., • Two-photon (gg) process RH beams e– e+ Suppressed by RH polarized electron beams N4f(500 fb–1)  10k @ 90% RH Lower energy t’s N2g(500 fb–1)  13M events! We need to detect e– and e+ going very close to the beam direction (down to 2o or1o).

  38. Number of Events vs. DM • Number of SUSY events for 500 fb-1 of luminosity as a function of DM for m0 = 203~220 GeV with all the event selection cuts • We can discover SUSY at LC with 1o! N2g = 249 for 2o N2g = 4 for 1o R. Arnowitt, B.D., T. Kamon, V. Khotilovich, hep-ph/0411102

  39. Accuracy of Mass Determination • NEED: 1o coverage at 500-GeV LC • d(DM)/DM ~ 10% m1/2=360 ~ ~ R. Arnowitt, B.D., T. Kamon, V. Khotilovich, hep-ph/0411102

  40. Study of SUSY Signals at the LHC • The LHC is powerful enough to produce many SUSY particles. • Can we detect the co-annihilation signal (small DM)?

  41. Measurement of DM at the LHC • Squark-gluino production cross section is very large. • Key decay: • Signal:>3t (two high and one low energy) + jets (q’s, g’s) + missing energy ( ) • Backgrounds: SM and other SUSY processes A. Arusano, R. Arnowitt, B.D., T. Kamon, D. Toback, P. Wagner

  42. SUSY Signals at the Tevatron • Direct searches • The reach is 200 GeV for m1/2 • Promising search: Bs m+m- • SM branching ration: 10-9 • SUSY: 10-7~10-8 V. Krutelyov, R. Arnowitt, B.D., T. Kamon, P. McIntyre, Y. Santoso, Phys. Lett. B505, 161 (2001) R. Arnowitt, B.D., T. Kamon, M. Tanaka, Phys. Lett. B538, 121 (2002) V. Krutelyov, Ph.D. thesis, May 2005 (expected)

  43. Conclusion • SUSYcures the problems of the SM. • It fulfills the dream of Grand Unification and explains the dark matter (DM) content. • The minimal supergravity (mSUGRA) model, based on the unification framework, is already constrained by many experiments. • The DM content of the universe requires some specific features of the mSUGRA parameter space e.g. co-annihilation. • The signal of the co-annihilation at the colliders will confirm the model. • A linear collider will be able to probe this signal and accurately measure the mass. • We think that the LHC will also be able to probe this signal.

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