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Bhaskar Dutta Texas A&M University

23% of the Universe at the Large Hadron Collider. Colloquium, 03/13/08 Texas Tech University. Bhaskar Dutta Texas A&M University. Supported by. Collision of 2 Galaxy Clusters. splitting normal matter and dark matter apart. – Another Clear Evidence of Dark Matter – (8/21/06).

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Bhaskar Dutta Texas A&M University

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  1. 23% of the Universe at the Large Hadron Collider Colloquium, 03/13/08 Texas Tech University Bhaskar Dutta Texas A&M University Supported by 23% of the Universe at the LHC

  2. Collision of 2 Galaxy Clusters splitting normal matter and dark matter apart – Another Clear Evidence of Dark Matter – (8/21/06) 23% of the Universe at the LHC

  3. Contents of the Universe 4% The 23% is not observed in the laboratory.. This new matter can not be seen visually! Cold Dark Matter (CDM) 23% of the Universe at the LHC 23% of the Universe at the LHC 3

  4. What is Dark Matter? • MENU • ~SPECIALS~ • *Dark Energy Power Drink .. $73 • - Chef’s choice • *Dark Matter Sandwich …… $23 • - Neutral, long-lived • *Atomic Soup ………………. $4 • - All elements in one Cafe Universe Can it be one of the known particles? 23% of the Universe at the LHC

  5. CDM in The Standard Model? The Standard Model (SM) describes all these particles and 3 of 4 forces. We have confirmed the existence of those in the laboratory experiments. 23% of the Universe at the LHC

  6. No! X X X X X X X X X X X X X X X X Quarks, electron, muon, tau particles, and force carriers can not be the dark matter, since their interactions are stronger than what we expect. Neutrinos can, but they are too light! X We need new idea, based on a new symmetry. Supersymmetry or SUSY 23% of the Universe at the LHC

  7. New Model The Standard Model : • Cannot provide a dark matter candidate. • Has a serious Higgs mass divergence problem due to quantum correction. • Cannot accommodate masses for neutrinos. • Cannot provide enough matter-antimatter asymmetry. Standard Model has fallen! Supersymmetry : • Provides a candidate for dark matter ~ neutralino. • Solves the Higgs mass problem in a very elegant way. • Supersymmetric grand unified models include neutrinos! Dutta, Mimura, Moahapatra, PRL 96, (2006) 061801; 94, (2005) 091804; PRD 72 (2005) 075009; (2004) 115014 • Can produce correct matter-antimatter asymmtery Dutta, Kumar, Leblond, JHEP 0707 (2007) 045; Dutta, Kumar, PLB 643 (2006) 284 • What is the new model? • Can the neutralino be detected and consistent with the dark matter content of the Universe? 23% of the Universe at the LHC 23% of the Universe at the LHC 7

  8. Higgs and Fermion Masses • [1] The Higgs Mass (Mh) has the following bounds : • 114 GeV < Mh < 182 GeV in the SM • 114 GeV < Mh < 150 GeV in minimal SUSY model • Tevatron and/or LHC will probe this Higgs mass. [2] In SM, there also exists a tremendous hierarchy among the fermion masses, e.g., mt/me=105.  Attempts are being made to understand the origin of these hierarchies in the context of string motivated SUSY models. 23% of the Universe at the LHC 23% of the Universe at the LHC 8

  9. Particle Physics and Cosmology Astrophysics CDM = Neutralino ( ) SUSY LHC LHC LHC SUSY is an interesting class of models to provide a weakly interacting massive neutral particle (M ~ 100 GeV). LHC 23% of the Universe at the LHC 23% of the Universe at the LHC 9

  10. When Were the DM Particles Created? Now ~380,000 years CMB ~0.0000001 seconds 23% of the Universe at the LHC 23% of the Universe at the LHC 10

  11. Supersymmetrized SM • The fundamental law(s) of nature is hypothesized to be symmetric between bosons and fermions. • Fermion Boson • Have they been observed? ➩ Not yet. 23% of the Universe at the LHC

  12. SUSY Transition Diagrams SUSY partner of W boson: chargino SUSY partner of tlepton: stau SUSY partner of Z boson: neutralino Lightest neutralinos are always in the final state! This neutralino is the dark matter candidate!! 23% of the Universe at the LHC

  13. Dream of the Unification ☹ ☺ U(1)Y Force U(1)Y Force Grand Unified Theory [GUT] The grand unification of forces occur in SUSY models. 23% of the Universe at the LHC

  14. MHiggs > 114 GeV Mchargino > 104 GeV 2.2x10-4 <B(bsg) <4.5x10-4 (g-2)m : 3 s deviation from SM Minimal Supergravity (mSUGRA) <H> = 246 GeV <Hu> b <Hd> SUSY model in the framework of unification: + Key Experimental Constraints 4 parameters + 1 sign tanb<Hu>/<Hd> at MZ m1/2 Common gaugino mass at MGUT m0 Common scalar mass at MGUT A0 Trilinear couping at MGUT sign(m) Sign of m in W(2) = m HuHd Arnowitt, Chamesdinne, Nath, PRL 49 (1982) 970; NPB 227 (1983) 121. Barbieri, Ferrara, Savoy, PLB 119 (1982) 343. Lykken, Hall, Weinberg, PRD 27 (1983) 2359. 23% of the Universe at the LHC

  15. Anatomy of WCDM º - Δ M M M ~ ~ t 0 c 1 1 + …. Co-annihilation Process Griest, Seckel ’91 + + …. Use well motivated mSUGRA as a benchmark model 23% of the Universe at the LHC

  16. Dark Matter Allowed Regions Focus-point Region Arnowitt, Dutta, Santoso, NPB 606 (2001) 59 Arnowitt, Dutta, Hu, Santoso, PLB 505 (2001) 177 Allahverdi, Dutta, Mazumdar, PRD 75 (2007) 075018 Co-annihilation Region 23% of the Universe at the LHC

  17. Dark Matter Allowed Region Co-annihilation Region 23% of the Universe at the LHC 23% of the Universe at the LHC 17

  18. Probing the susy Dark Matter LHC, Tevatron - Accelerator Wc≟0.23 Production & Decay Direct Detection of DM ! @ LUX, XENON 100, CDMS etc Detector DM Hunters 23% of the Universe at the LHC

  19. Model Parameters and Expts. Sparticle1 p,e+ p,e-,p Sparticle2 b SUSY p1 p2 SUSY Particles can be directly produced at the colliders • Colliders: • Large Hadron Collider (pp) (In a year), • Tevatron (pp) (running), • International Linear Collider (e+e-) (future?) Indirect effects: • Rare Decays of B meson at Tevatron & B factories Arnowitt, Dutta, Hu, Oh, PLB 641 (2006) 305; PLB 633 (2006) 748; Dutta, Kim, Oh, PRL 90 (2003) 011801 • Dark Matter Detection Experiments 23% of the Universe at the LHC

  20. Tevatron and Cosmology Tevatron and Cosmological Connection SUSY particles can be directly produced at the Tevatron We found the reach is not high! [Krutelyov, Arnowitt, Dutta, Kamon, McIntyre, Santoso, Phys. Lett. B505, (2001) 161] But, we propose a promising experimental signal [Arnowitt Dutta, Kamon, Tanaka, Phys. Lett. B 538 (2002) 121]: Bs m+m- 23% of the Universe at the LHC

  21. Rare Decay Bsm+m- Within the SM, we will not see any events even with 100 x 1012 collisions. In the SUSY models (large tanb), which are cosmologically consistent, the decay can be enhanced by up to 1,000. 23% of the Universe at the LHC

  22. 23% of the Universe at the LHC 23% of the Universe at the LHC

  23. LHC and Cosmological Connection 1x10-7 2x10-7 mSUGRA signal at the LHC mSUGRA at tanb = 50 Arnowitt, Dutta, et al., PLB 538 (2002) 121 23% of the Universe at the LHC

  24. LHC = Large Hadron Collider ATLAS CMS (*) Two large international collaborations. (*) TAMU is a CMS member institution. blue and reddots and yellowlines are studied to figure out what happens in the collision! PHYSICS is extracted out of many trillion pp collisions. Arnowitt, Dutta, Kamon, Kolev, Toback, PLB 639 (2006) 46 Arnowitt, Arusano, Dutta, Kamon, Kolev, Simeon, Toback, Wagner, PLB 649 (2007) 73 Arnowitt, Dutta, Gurrola, Kamon, Krislock, Toback, arXiv:0802.2968 23% of the Universe at the LHC 23% of the Universe at the LHC 24

  25. First Analysis at the LHC Kinematical Cuts to Establish SUSY • PTj1>100 GeV, PTj2,3,4> 50 GeV • Meff > 400 GeV (Meff is a scalar sum of PTj1,2,3,4 and PTmiss) • PTmiss > max [100, 0.2 Meff] Hinchliffe, Paige, Phys. Rev. D 55 (1997) 5520 The heavy SUSY particle mass is measured by combining the final state particles q q q q 23% of the Universe at the LHC

  26. Meff and Relic Density SUSY scale is measured with an accuracy of 10-20% • This measurement does not tell us whether the model can generate the right amount of dark matter • The dark matter content is measured to be 23% with an accuracy of around 3% at WMAP • Questions: How can we establish the dark matter allowed regions? To what accuracy can we calculate the relic density based on the measurements at the LHC? 23% of the Universe at the LHC

  27. Coannihilation Region at the LHC One of the key reactions Unique kinematics >3 jet + PTmiss+ >2t 23% of the Universe at the LHC

  28. Coannihilation Region (tanb=40) tanb = 40, m > 0, A0 = 0 Phys. Lett. B 649 (2007) 73 Can we measure DM at the LHC? 23% of the Universe at the LHC

  29. Anatomy – Mass Distribution 10 fb-1 OS LS OS-LS pTt > 20 GeV is essential! Phys. Lett. B 639 (2006) 46 Mmax(true)= 78.7 GeV Mpeak= 47.1 GeV SUSY :125 counts (Mtt< 100 GeV) 23% of the Universe at the LHC 23% of the Universe at the LHC 29

  30. Anatomy – Mass Distribution (2) OS LS OS-LS GOAL: Establish the path for a well motivated SUSY scenario before the experiment starts in 2008. Probing squark mass 23% of the Universe at the LHC 23% of the Universe at the LHC 30

  31. Five Observables • Sort t’s by ET (ET1 > ET2 > …) • Use OS-LS method to extract t pairs from the decays SM+SUSY Background gets reduced • Ditau invariant mass: Mtt • Jet-t-t invariant mass: Mjtt • Jet-t invariant mass: Mjt • PT of the low energy t • Meff : 4 jets +missing energy • Meff (b) : 4 jets (leading jet is a b quark) +missing energy All these variables depend on masses => model parameters Since we are using 6 variables, we can measure the model parameters and the grand unified scale symmetry (a major ingredient of this model) 23% of the Universe at the LHC

  32. How to Establish the Discovery ~ c 0 1 ~ c 0 2 Phys. Lett. B 639 (2006) 46; Phys. Lett. B 649 (2007) 73; arXiv:0802.2968 [1] Low energy t’s are crucial to discover the DM allowed region. [2] We construct different observables involving these t’s. [3] We study Mjtt, Mtt etc distributions and their properties: e.g., Peak(Mtt) = f (Msquark, Mstau, M , M ) [4] Squark and stau masses can be expressed in terms of m0, m1/2, A0, tanb. Note our observables are not that sensitive to A0 and tanb in the dark matter allowed region [5] We use these observables to solve for m0 , m1/2, A0, tanb [6] We can now calculate the dark matter content 23% of the Universe at the LHC

  33. Dark Matter at TAMU Kamon, Safonov, and Toback will use the path to accurately measure the model parameters from the detailed features of the signals (real data) when the LHC will start. Synergism between the theorists and the experimentalists We then calculate the relic density and compare with WMAP. 23% of the Universe at the LHC

  34. Determining Model Parameters 10 fb-1 We can also determine the sparticle masses using these observables and a few additional ones, e.g., M(peak), etc jt m0=205 4; m1/2=350 4.2; A0=0 16; tanb= 40 0.8 =748 25; =831 21; =10.6 2; =141 19; = 260 15; The Model parameters are solved by inverting the following functions: (in GeV) 23% of the Universe at the LHC

  35. GUT Scale Symmetry m1/2 ~ ~ g g mass ~ ~ c c 0 0 1 1 ~ ~ c c 0 0 2 2 MGUT Log[Q] MZ We can also probe the physics at the Grand unified theory (GUT) scale Use the masses measured at the LHC and evolve them to the GUT scale using mSUGRA The masses , , unify at the grand unified scale in SUGRA models We can measure this unification to an accuracy of <5% Another evidence of a symmetry at the grand unifying scale! 23% of the Universe at the LHC

  36. Relic Density and Luminosity • How does the uncertainty in the Dark Matter relic density change with Luminosity? dWh2/Wh2 ~ 6% (30 fb-1) 23% of the Universe at the LHC

  37. DM Particle: Direct Detection? The measurement at the LHC will pinpoint the parameters of SUSY models. We can predict the direct detection probability of dark matter particles. µ (*) Complementary measurements ! detector Dark Matter particle (*)The TAMU group is one of the leading institutions in the US. 23% of the Universe at the LHC 23% of the Universe at the LHC 37

  38. Status - Direct Detection • Ongoing/future projects: CDMS, ZEPLIN, XENON10, LUX • Status: • DAMA group (Italy) – claims to have observed some events. • CDMS,ZEPLIN,XENON10 – dispute their claim. DAMA CDMS ZEPLIN XENON10 DAMA 10-8 pb Accomando, Arnowitt, Dutta, Santoso, NPB 585 (2000) 124 [Cross section < 9 x 10-8 pb for 100 GeV neutralino] Close to the current sensitivity 23% of the Universe at the LHC

  39. International Linear Collider (ILC) CDM Allowed Region and Kinematical Reach for t1+t1- & c20c10 The plan is to build an ILC after the LHC starts running! Dark matter content will be known with higher precision. The parameters of SUSY models can be measured with a greater accuracy Khotilovich, Arnowitt, Dutta, Kamon, PLB 618 (2005) 182 23% of the Universe at the LHC 23% of the Universe at the LHC 39

  40. Conclusion • SM of particle physics has fallen. • Supersymmetry seems to be natural in the rescue act and the dark matter content of the universe can be explained in this theory. • The minimal SUGRA model is consistent with the existing experimental results. [1] LHC can probe the minimal SUGRA model directly. • The dark matter content can be measured with a high accuracy . [2] Direct detection experiments will simultaneously confirm the existence of these models. [3] Future international linear collider will shed further light! 23% of the Universe at the LHC 23% of the Universe at the LHC 40

  41. My Vision Diagram & Models 23% of the Universe at the LHC 23% of the Universe at the LHC 41

  42. Conclusion… 23% of the Universe at the LHC 23% of the Universe at the LHC 42

  43. Backups 23% of the Universe at the LHC

  44. mSUGRA Case Study at tanb= 40 m1/2= 360, m0= 215, tanb = 40, mtop= 175 (LCC3 Point) 97% 100% 23% of the Universe at the LHC

  45. 180 23% of the Universe at the LHC 23% of the Universe at the LHC 45

  46. Meff Distribution: 4j + ETmiss • ETj1>100 GeV, ETj2,3,4> 50 GeV [No e’s, m’s with pT > 20 GeV] • Meff > 400 GeV (Meff ETj1+ETj2+ETj3+ETj4+ ETmiss[No b jets; eb ~ 50%]) • ETmiss > max [100, 0.2 Meff] At Reference Point Meffpeak = 1220 GeV (m1/2 = 335 GeV) Meffpeak = 1331 GeV (m1/2 = 365 GeV) Meffpeak = 1274 GeV 23% of the Universe at the LHC

  47. Meff(b) Distribution • ETj1>100 GeV, ETj2,3,4> 50 GeV [No e’s, m’s with pT > 20 GeV] • Meff(b)> 400 GeV (Meff(b)ETj1=b+ETj2+ETj3+ETj4+ ETmiss[j1 = b jet]) • ETmiss > max [100, 0.2 Meff] At Reference Point Meff(b)peak = 933 GeV (m1/2 = 335 GeV) Meff(b)peak = 1122 GeV (m1/2 = 365 GeV) Meff(b)peak = 1026 GeV Meff(b) can be used to determine A0 and tanb even without measuring stop and sbottom masses 23% of the Universe at the LHC

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