1. Saclay, France1 Search for Dark Matter Using The CMS Detector at CERN Vasken Hagopian Lannutti Professor (Emeritus) of Physics Florida State University October 2010

2. Google: Astronomy – Dark Matter 2 million hits!!! October 20102Saclay, France Very popular Subject Popular magazines!

3. Dark Matter Evidence from Astronomy. Searches in laboratories looking for annihilation or scattering of dark matter. Mostly limited to Weakly Interaction Massive Particles (WIMP) Latest results -- Xenon100 and CDMS II Satellite searches (Pamela) Searches using accelerators October 20103Saclay, France

4. 4 p.91 Isaac Newton 1702 Inertial Mass F = ma Gravitational Mass F = Gm 1 m 2 /r² What is mass? October 2010

5. Saclay, France5 p. 213 Albert Einstein Mass is Energy E = mc² 1905 October 2010

6. Saclay, France6 What is Dark Matter? Matter that has mass but does not interact with ordinary matter except by gravity, and possibly by weak forces --WIMP’s. Does not interact with photons, i.e. we cannot “see” it. Mass can be small (particles) or large (planet or star size)! First postulated by Fritz Zwicky in 1934 to explain galaxy velocities in galactic clusters. October 2010

7. Saclay, France7 What is Dark Matter? It has gravitational attraction to other mass. F = Gm 1 m 2 /r². October 2010

8. Saclay, France8 The Evidence of Dark Matter From Astronomical Observations 1.Mass of spiral galaxies. 2.Mass of galactic clusters. 3.Dark matter observed from colliding galaxies. 4.Distribution of galactic clusters. 5.Microwave background from Big Bang. October 2010

9. 1 st 1 st Evidence of Dark Matter Mass of Spiral Galaxies 1.Visible mass (stars and nebula) determined by direct observations. 2.Galaxy mass from galaxy rotation. Saclay, France9October 2010

10. Saclay, France10 Mass of stars Kepler’s Third Law (1618) Determined best from binary star systems. M 1 + M 2 = a 3 /p 2. where M is in solar mass units, a is distance in astronomical units (distance between Earth and Sun) and p is the period of revolution in years. M(Sun) = 2  10 30 kg. a = 1.5  10 11 m. October 2010

11. Saclay, France11 Dark Matter Dark Matter in Spiral Galaxy First announcement by Vera Rubin in 1975 mv 2 /R = GmM/R 2 October 2010

12. Saclay, France12 Mass of a typical spiral galaxy About 50% of mass of spiral galaxies is observed. dark matterThe other 50% of mass is unknown and is called dark matter. “Dark” for astronomers mean unknown!! October 2010

13. Recent result--Dwarf galaxies October 2010Saclay, France13 Dark matter 99% of galaxy mass. Another galaxy has 99.9% dark matter

14. Saclay, France14 2 nd 2 nd Evidence of Dark Matter In Galactic Clusters (1934) Clusters are Gravitationally bound. Almost all galaxies are in clusters. Mass determined from the motion of galaxies in the clusters. October 2010

15. Saclay, France15 Galaxy Clusters October 2010 Coma clusterDeep Space - Hubble

16. Dark matter between Galaxies in Cluster of Galaxies Velocities of galaxies in clusters are large and the cluster would have disintegrated over the age of the universe, unless the cluster has more mass to bind gravitationally. Mass (dark) between galaxies 2 to 3 times galaxy masses. Saclay, France16October 2010

17. 3 rd 3 rd Evidence of Dark Matter Colliding galaxies In colliding galaxies, dark matter moves faster than normal matter that is slowed by gravity. Saclay, France17 Blue (dark matter) Determined by gravitational lensing. Pink is ordinary mass from X-ray observations Dark matter cannot be dead stars or planets. October 2010

18. Bullet cluster October 201018Saclay, France “This view of the Bullet Cluster combines an image from NASA's Chandra X-ray Observatory with optical data from the Hubble Space Telescope and the Magellan telescope in Chile. This cluster, was formed after the violent collision of two large clusters of galaxies. It has become an extremely popular object for astrophysical research, including studies of the properties of dark matter.”

19. Saclay, France19 4 th 4 th Evidence of Dark Matter Structure of Universe particulateAnalysis of galactic structure requires dark matter to be particulate. Not stellar masses. October 2010

20. Big Bang Model of Universe Universe started from a single explosion about 13.7 billion years ago! v = H × d v - recession velocity. d - distance When the universe expanded and cooled to (3,000 °K) the protons and electrons formed neutral hydrogen molecule in about 380,000 years the universe got transparent. Microwave background comes from the original heat at 3,000 °K that has cooled by now to 2.7°K. Saclay, France20October 2010

21. 5 th Evidence of Dark Matter. (WMAP) Microwave Anisotropy Probe Saclay, France21October 2010

22. Saclay, France22 WMAP (From Fitting Distribution) Energy Balance of the Universe 5% normal baryonic matter 23% dark matter (not baryons). 72% dark energy. Dark matter is >4 times normal matter. Most dark matter is cold, low velocity. Neutrinos make up << 1% of dark matter Black holes make up <<1% universe. October 2010

23. Dark Matter Dark matter exists ~5 times normal matter Dark matter is particulate and cold v < 0.1c So, what is it?  Dark matter particles do not interact with each other.  Perfect fluid – no internal resistance or viscosity. Saclay, France23October 2010

24. Saclay, France24 What is Dark Energy? Dark energy has nothing to do with dark matter! Dark energy is the mysterious force that is expanding the outer edges of the universe. General Theory of Relativity has DARK ENERGY. The Cosmological Constant (Λ ) in Einstein equation of General Theory of Gravity d 2 R/dt 2 = (4/3)ρGR + ΛR/3 is DARK ENERGY. It is not known if observed Dark Energy is the same as the Cosmological Constant October 2010

25. Saclay, France25October 2010

26. Saclay, France26 Dark Matter Searches and Candidates Neutrinos with mass. Mass is too small to account for much of the dark matter. <<1%. Black holes. Stellar and massive black holes << 1% of dark matter. MACHOs. Massive compact halo objects. Need so many that it should be observed by now in abundance. Detected by gravitational lensing, but <1%. WIMPs. Weakly interacting massive particles. E.g. Neutralino. Many underground searches. SUSY, Extra Dimensions, Etc. None observed yet. (Searches at the Tevatron and now LHC- CERN) October 2010

27. Saclay, France27 Cold Dark Matter Searches A sample of terrestrial experiments Looking for Dark Matter via recoiling atoms. DAMA: Gran Sasso, Italy. 1998, NaI, 100Kg. DAMA and DAMA/LIBRA claimed to detect dark matter from annual variation of event rate, but results are incompatible with other experiments. Edelweiss: Frejus, France. 2001, Germanium, 1.3Kg. UKDMC: Boulby, UK, 1997, NaI, 5 Kg. PICASSO: Sudsbury, Canada, 2000, Freon, 0.001Kg. Rosebud: Canfranc, Spain, 1999, Aluminum oxide, 0.05kg Recent results: CDMS II and Xenon100  next pages None observed conclusively. October 2010

28. Latest results from CDMS II Soudan mine (3/2010) CDMS (I&II) Sudan, US. Ge 0.23kg and Si 0.1kg. CDMS - Cryogenic Dark Matter Search (CDMS II) Detector is low temperature germanium particle detectors. Searching for WIMP (Weakly Interacting Massive particles). “Yielded two candidate events, with an expected background of 0.9 ± 0.2 events. This is not statistically significant evidence for a WIMP signal.” October 201028Saclay, France

29. Xenon 100 – Grand Sasso PRL 24 September 2010 October 201029Saclay, France E. Aprile et al, PRL 105 131302 (2010) First Dark Matter Results from Xenon100 Experiment CDMS and XENON100 Have implications on the Higgs sector.

30. Two recent space experiments Indirect detection looking for products of WIMP annihilation. ATIC balloon experiment has observed excess of electrons and/or positrons over Antarctica. Pamela satellite has observed excess of positrons in space, but not anti-protons.  See next two pages Could these be annihilation of dark matter? There are other possibilities for the excess of positrons (nearby pulsars?). Saclay, France30October 2010

31. Saclay, France31 Excess of positrons

32. October 2010Saclay, France32 O. Adriani, et. al, PRL 121101 No excess of anti-protons

33. Saclay, France33 Search for Dark Matter using Particle Accelerators 1.New particles (A) created in pairs or singly. p + p  A + Ā + X; OR p + p  A + X, if particle is its own antiparticle. 2.New generation of particles (SUSY) with lowest mass being a neutral stable particle. p + p  A + Ā + X ↳ A 0 + Y where A 0 is stable. A 0 shows up as missing energy! October 2010

34. How to search for dark matter Dark matter cannot be observed directly in accelerators. Look for associated particles or jets as signature with missing energy (E T ). Popular searches are for neutralino (WIMP), extra dimensions. We are looking for the dark sector with muon jets. October 201034Saclay, France

35. 35 Particle Accelerators and Detectors Fermilab Collider at 1 TeV + 1 TeV p + anti-p Major Detectors DØ and CDF CERN LHC 7 TeV + 7 TeV (3.5+3.5 in 2010) p + p Major Detectors: CMS and ATLAS October 2010

36. Saclay, France36 Standard Model Elementary particles composed of 1.Quarks (e.g. proton, neutron) 2.Leptons (e.g. electron) Three forces acting on particles: strong, electromagnetic, weak. Fourth force is gravity. October 2010

37. “Theoretical” dark matter candidates (beyond standard model) Supersymmetry (SUSY) solves SM problems. Creates a new family of particles. Eliminates the fine tuning problems in SM. Unification of the three coupling constants at a high mass scale. ark matter candidate (. Dark matter candidate (neutralino). Some theories have neutralino annihilating and producing positrons! Some theories have neutralino annihilating and producing positrons! Extra Dimensions have dark matter candidate.Extra Dimensions have dark matter candidate. October 201037Saclay, France

38. 38 How to Search for Dark Matter in colliders Collider detectors observe all known particles except neutrinos. Look for large unbalanced momentum events (missing E T ). Eliminate all known productions that have neutrinos. Fit the distributions of the remaining events to dark matter predictions, such as neutralinos. Use Advanced Analysis techniques such as Neural Networks to separate signal from background. October 2010

39. Dark matter signals Dark matter cannot be observed directly. Use other parts of an event to search for candidates, such as quark jets, muon jets, etc. Use models to search for dark matter candidates. October 201039Saclay, France

40. Tevatron Searches Both D0 and CDF have search for dark matter candidates. Dark matter shows up as deviations from the standard model. E.g SUSY searches. Tevatron mass limits of the neutralino are 200 to 300 GeV/c 2. October 201040Saclay, France

41. Extra Dimensions One and Two dimensions Think about an acrobat and a bug on a tight rope. The acrobat can move forward and backward along the rope. But the bug can also move sideways around the rope. If the bug keeps walking to one side, it goes around the rope and winds up where it started. It has no center or end. October 201041Saclay, France An acrobat can only move in one dimension …but a flea can move in two dimensions

42. Extra Dimensions has dark matter candidate We have four known dimension. Why is gravity so weak compared to the other three known forces? Does gravity propagate in extra dimensions? If a graviton escapes into an extra dimension it cannot be “seen” but still has gravity. Is the graviton dark matter? Saclay, France42October 2010

43. Kaluza-Klein Extra dimension Extra Dimensions dark matter candidate.Extra Dimensions also provides dark matter candidate. Extra Dimensions first proposed in the 1930’s. A reason for gravity to be so weak. Graviton can be in this extra dimension. Graviton  dark matter? October 201043Saclay, France Fermilab D0 candidate

44. Saclay, France44October 2010

45. Saclay, France45 CERN in Geneva, Switzerland CMS CERN Lab October 2010

46. Saclay, France46 LHC: 2009 Start Higgs, SUSY, Extra Dimensions, CP Violation, QG Plasma, … the Unexpected October 2010

47. Saclay, France47 CERN CMS Detector October 2010

48. Saclay, France48October 2010 CMS at LHC

49. CMS Events are “busy” October 2010Saclay, France49

50. Luminosity October 201050Saclay, France

51. Muons, electrons October 201051Saclay, France

52. October 2010Saclay, France52

53. Top quark pair event October 201053Saclay, France

54. Search for SUSY and Extra Dimensions at LHC Events are complex with many decay products. Look for multi-jet events with large missing E T. Look for multi-lepton events with large missing E T. Look for excess in multi lepton distributions. Single leptons with large missing E T. Etc. October 201054Saclay, France

55. October 2010Saclay, France55

56. Two di-muon events with large missing E T October 201056Saclay, France

57. 57 October 2010 Simulation SUSY

58. Saclay, France58 Summary Dark matterDark matter should exist. Expect to discover Dark Matter using LHC Particle Accelerator and CMS detector, if mass is below several TeV. Lowest mass neutral SUSY particle is a good candidate of Dark Matter. Neutralino (a majorana fermion)? What is Dark Matter. Not yet known. When was it produced? Early universe(?) October 2010

59. BACKUP Saclay, France59October 2010

60. Can the LHC make black holes? What is a black hole? When escape velocity is larger than velocity of light, then not even light can escape. Escape velocity = √(2GM/R) The larger the mass, the larger the escape velocity The smaller the size (R) the larger the escape velocity Saclay, France60October 2010

61. Black Holes Let us do the numbers Escape velocity of Earth = 11 km/sec Escape velocity of Sun = 610 km/sec When escape velocity = velocity of light R = 3 km for Sun [Sun R = 700,000 km] For 14 TeV proton, R = 3 × 10 -50 meter Or squeeze the two protons 100,000,000,000,000,000,000,000,000,000,000,000 times Saclay, France61October 2010

62. Saclay, France62 Mass of Spiral Galaxies Composition of Galaxies 1.Stars 2.Nebula (~25% of visible mass) 3.Planets (<< 1%) 4.Other non luminous “stars” < 1%. 5.Black holes <1% 6.Dark matter (~50%) October 2010

63. Saclay, France63 Horsehead Nebula October 2010

64. Saclay, France64 Mass of Galactic Clusters Gravitationally Bound Viral Theorem Potential energy = - GM 2 / R. Kinetic energy = ½M 2. Gravitationally bound |PE| = 2×KE Compute mass M. dark matter.Typically M is several times the sum of the masses of galaxies. The rest is dark matter. October 2010

65. WMAP Saclay, France65October 2010

66. Saclay, France66 Evidence of Dark Energy Edge of Universe is expanding faster than predicted by the Big Bang. This mysterious force is due to Dark Energy! Evidence from Type 1a supernova Standard candle October 2010

67. Saclay, France67 MACHO’s Observed by the lensing effect of gravity October 2010

68. Saclay, France68 Black Holes (<< 1% of mass of galaxies) Left – 10 9 M  Top – 3×10 9 M  M  = 1 Solar mass October 2010

69. Saclay, France69 Schematic View of CMS Minus Side Plus Side October 2010

70. Saclay, France70October 2010

71. CMS during installation Saclay, France71October 2010

72. Saclay, France72 Data Taking First LHC Beam (10 Sept) From Sept CMS Week (two goals - now DONE):  - take solenoid to operating field (and 4T to test margin, fast dump etc..) - take an adequately long CRAFT run and better understand the detector. CRAFT (17 Oct - 11 Nov @3.8T) ~ 300 M cosmic triggers recorded. October 2010