The first one second of the early universe and physics beyond the Standard Model

Transcription

1 The first one second of the early universe and physics beyond the Standard Model Koichi Hamaguchi (University of Colloquium at Yonsei University, November 9th, Credit: X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.

2 elementary particles quark proton / neutron electron e nucleus atom

3 elementary particles quark quark up U d down proton / neutron lepton e electron νe neutrino electron e nucleus

4 elementary particles 1st gen. 2nd gen. 3rd gen. U c t g quark up d down charm s strange top b bottom gluon γ photon gauge bosons lepton e electron νe μ muon νμ τ tau ντ Z W W, Z-bosons e-neutrino -neutrino -neutrino h Higgs boson The Standard Model of Particle Physics

5 1st gen. 2nd gen. 3rd gen. U c t g quark up d down charm s strange top b bottom gluon γ photon gauge bosons lepton e electron νe μ muon νμ τ tau ντ Z W W, Z-bosons discovered in 2012 e-neutrino -neutrino -neutrino h Higgs boson The Standard Model of Particle Physics

6 e U d Standard Model μ c s τ νe νμ ντ t b g γ Z W h Higgs field: e.g. electron: gives masses to other particles. 6

7 e U d Standard Model μ c s τ νe νμ ντ t b g γ Z W h Higgs field: e.g. electron: gives masses to other particles. right-handed left-handed (not weakly interacting) (weakly interacting) 7

8 e U d Standard Model μ c s τ νe νμ ντ t b g γ Z W h Higgs field: gives masses to other particles. e.g. electron: without Higgs,... (not weakly interacting) right-handed left-handed (weakly interacting) different particles!! zero masses! (moving with a speed of light) 8

9 e U d Standard Model μ c s τ νe νμ ντ t b g γ Z W h Higgs field: gives masses to other particles. e.g. electron: the Higgs connects the two components. (not weakly interacting) right-handed left-handed (weakly interacting) Yukawa interaction Higgs 9

10 e U d Standard Model μ c s τ νe νμ ντ t b g γ Z W h Higgs field: gives masses to other particles. e.g. electron: thanks to the Higgs condensation in vacuum... Higgs the two components are exchanged --> the electron gets a mass!! 10

11 Anyway,... Standard Model e U d μ c s τ νe νμ ντ t b g γ Z W h The last piece was found. Is this the end of the story...?

12 Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Dark Energy initial condition of Universe Matter > Anti-matter Dark Matter Particle Physics complicated quark/lepton properties Higgs naturalness tiny neutrino mass Today, I will explain some of those motivations for BSM physics and candidates for BSM physics. 12

13 Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Particle Physics complicated quark/lepton properties Let s start from here. 13

14 e U d Standard Model μ c s τ νe νμ ντ t b g γ Z W h Other quarks and leptons get masses in similar ways. Left + Right Higgs the two components are exchanged --> the electron gets a mass!! 14

15 If we write R and L separately,... (only 1st gen.) left-handed quark ( U d )L right-handed up quark ( U)R d - - right-handed down quark ( )R left-handed lepton ( e ( )L e )R (3,2)+1/6 (3,1)-2/3 (3,1)+1/3 (1,2)-1/2 (1,1)+1 νe right-handed lepton hyper charge Feel strong force Feel weak force Don t feel strong force Don t feel weak force... very complicated!! Q: any simple, unified theory to explain it? 15

16 Standard Model ( U d )L ( U)R d - - ( )R ( e ( )L e )R (3,2)+1/6 (3,1)-2/3 (3,1)+1/3 (1,2)-1/2 (1,1)+1 νe Q: any simple, unified theory to explain it? electronic magnetic} Standard Model electromagnetic weak } electroweak strong } Grand Unified Theory!! 16

17 Standard Model ( U d )L ( U)R d - - ( )R ( e ( )L e )R (3,2)+1/6 (3,1)-2/3 (3,1)+1/3 (1,2)-1/2 (1,1)+1 νe Q: any simple, unified theory to explain it? Grand Unified Theory [ SU(5) case ] ( U R) d L U R e 10 ( e ) L d R νe 5-1/3 + 1/3 + 1/3-1/2-1/2 = 0 Complicated numbers are naturally explained!... beautifully unified into simple SU(5) representations! [Georgi, Glashow 1974] 17

18 Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Particle Physics complicated quark/lepton properties Grand Unified Theory 18

19 Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Particle Physics complicated quark/lepton properties Grand Unified Theory tiny neutrino mass Next, 19

20 puzzle: neutrino masses ( U d )L ( U)R d - - ( )R ( e )L (3,2)+1/6 (3,1)-2/3 (3,1)+1/3 (1,2)-1/2 νe ( e )R (1,1)+1 left-handed quark right-handed up quark right-handed down quark left-handed lepton right-handed lepton The neutrino has only left-handed component. recall the case of electron... 20

21 puzzle: neutrino masses ( U d )L ( U)R d - - ( )R ( e )L (3,2)+1/6 (3,1)-2/3 (3,1)+1/3 (1,2)-1/2 νe ( e )R (1,1)+1 left-handed quark right-handed up quark right-handed down quark left-handed lepton right-handed lepton The neutrino has only left-handed component. ===> Massless!! But the neutrino masses are confirmed by neutrino oscillations! 21

22 puzzle: neutrino masses ( U d )L ( U)R d - - ( )R ( e )L (3,2)+1/6 (3,1)-2/3 (3,1)+1/3 (1,2)-1/2 νe ( e )R (1,1)+1 N (1,1) left-handed quark right-handed up quark right-handed down quark left-handed lepton right-handed lepton right-handed neutrino a solution is... To add a right-handed neutrino!! 22

23 The right-handed neutrino N plays a triple role. 23

24 The right-handed neutrino N plays a triple role. quarks and leptons completely unified ( U R) d L U R e 10 ( e ) L d R GUT νe N 5 - SU(5) (1,1) ( U e R) d L U R e R νe L d R N1 16 SO(10) GUT All quarks and leptons unified! 24

25 The right-handed neutrino N plays a triple role. quarks and leptons completely unified ( U e R) = d L U R e R νe L d R N1 16 ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) 25

26 The right-handed neutrino N plays a triple role. explains tiny neutrino mass masses of quarks and leptons neutrinos ( 1, 2, 3 ) e,, quarks (u,d,s,c,b,t) why neutrino masses are so small?? 26

27 The right-handed neutrino N plays a triple role. explains tiny neutrino mass ( U d )L ( U)R d - - ( )R ( e ( )L e )R (3,2)+1/6 (3,1)-2/3 (3,1)+1/3 (1,2)-1/2 (1,1)+1 νe N (1,1) left-handed quark right-handed up quark right-handed down quark left-handed lepton right-handed lepton right-handed neutrino This guy is special... singlet (feels none of three (EM, weak, and strong) forces.) it has no charge. it can be its own anti-particle. it can have a mass without Higgs. 27

28 The right-handed neutrino N plays a triple role. explains tiny neutrino mass heavy R.H. small neutrino masses see-saw mechanism 28

29 The right-handed neutrino N plays a triple role. explains tiny neutrino mass 0.01 ev e.g. (100 GeV ) 2 e.g GeV heavy R.H. small neutrino masses see-saw mechanism 29

30 The right-handed neutrino N plays a triple role. explains matter > anti-matter asymmetry of the universe > Leptogenesis!! more on this later 30

31 Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Particle Physics complicated quark/lepton properties Grand Unified Theory tiny neutrino mass (heavy) Right- handed neutrino 31

32 Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Dark Energy Particle Physics complicated quark/lepton properties Grand Unified Theory initial condition of Universe Matter > Anti-matter Dark Matter tiny neutrino mass (heavy) Right- handed neutrino Next, 32

33 Our universe is expanding

34 Our universe is expanding going back now 1 sec 380,000 yrs 1.4x1010 yrs

35 Our universe is expanding going back now The early Universe was extremely hot and dense. Is it true? Any evidence?? 1 sec 380,000 yrs 1.4x1010 yrs

36 Photons emitted when the universe was 380,000 yrs old now = 1.4x1010 yrs old Cosmic Microwave Background are seen now, after 1.4x1010 yrs observation prediction of hot big-bang universe 1 sec 380,000 yrs 1.4x1010 yrs J.C.Mather et al. Astrophys. J. 354: L37-L40,

37 Photons emitted when the universe was 380,000 yrs old now = 1.4x1010 yrs old are seen now, after 1.4x1010 yrs OK, then, can we go back further? 1 sec 380,000 yrs 1.4x1010 yrs

38 Light elements (e.g., Helium-4) generated when the Universe was just O(1-1000) seconds old OK, then, what about the first one second? now = 1.4x1010 yrs old are seen now, after 1.4x1010 yrs 1 sec 380,000 yrs 1.4x1010 yrs Review of Particle Physics, PDG

39 There is no direct evidence what happened in the first one second. But there are puzzles that cannot be solved unless one understands this first one second.

40 Puzzles in our Universe known matter 5% Why no anti-matter? Dark Matter What is DM? 27% Dark Energy 68% What is DE? Furthermore problems of initial conditions

41 Puzzles in our Universe problems of initial conditions

42 Our Universe is very flat. Newton const. energy density of the Univrse flatness of the 8πG Universe Ω = 3 H 2 Hubble parameter (expansion rate) Ω > 1 closed Ω = 1 flat Ω < 1 open observation: Ω = ± (very flat) This is very, very strange! 42

43 According to Einstein eqs. But according to Standard Cosmology (Einstein eqs. + hot Big-bang Universe) 1 a 2 / ( t scalar factor of the Universe energy density of the Universe t 2/3 (for t<10000 yrs) (for t>10000 yrs) 43

44 According to Einstein eqs. But according to Standard Cosmology (Einstein eqs. + hot Big-bang Universe) 1 a 2 / ( t scalar factor of the Universe energy density of the Universe t 2/3 (for t<10000 yrs) (for t>10000 yrs) cosmic time t e.g., at t =1sec, 1 1sec now observation now ± The Universe was extreeeeeeeemly flat. Why? How? fine-tuning of initial condition. 44

45 Inflation: Assume that the Universe was initially dominated by vacuum energy (inflaton potential energy). Then,.. inflaton potential vacuum energy energy density scalar factor (exponential expansion: Inflation) Automatically tuned to be Ω = 1 (flat Universe)! 45

46 furthermore temperature fluctuation very, very well-explained by inflation! spherical-harmonic-function expansion 46

47 Puzzles in our Universe known matter 5% Why no anti-matter? Dark Matter 27% Dark Energy 68% problems of initial conditions

48 Each particle has its own anti-particle. particle anti-particle quark lepton e U d μ c s τ νe νμ ντ t b - U - -c - s d e- μ- τ νe νμ ντ - - t b anti-quark anti-lepton electron anti-particle positron charge: -1 charge: +1

49 In the very early Universe, sec 1 sec 380,000 yrs 1.4x1010 yrs

50 In the very early Universe,... The number of particles and anti-particles were almost the same. But there was tiny excess of matter over anti-matter. matter antimatter ,000,000

51 In the very early Universe,... The number of particles and anti-particles were almost the same. When the Universe got cooler, they pair-annihilated,.. matter antimatter ,000,000 matter - antimatter annihilation γ γ

52 In the very early Universe,... The number of particles and anti-particles were almost the same. When the Universe got cooler, they pair-annihilated,.. only matter remains (no antimatter) All of us Galaxy, the Earth, the human body,...) are made from this leftover matter.

53 Puzzle How was the initial excess of matter created? matter antimatter ,000,000 Wasn t it just there from the beginning? No!

54 Puzzle How was the initial excess of matter created? Inflation dilutes everything. １sec Matter and antimatter had to be generated from the vacuum energy. 380,000 yrs 14 Gyrs

55 Puzzle How was the initial excess of matter created? matter antimatter ,000,000

56 Puzzle How was the initial excess of matter created? Some mechanism ( Baryogenesis ) is necessary to create matter - antimatter asymmetry. Standard Model e U d μ c s τ νe νμ ντ t b g γ Z W h... does not work. Three necessary conditions for Baryogenesis [Sakharov 1967] Baryon number violation CP-violation... (but too small) out-of-equilibium Something beyond the Standard Model is necessary.

57 matter > antimatter requires physics beyond SM. Standard Model e U d μ c s τ νe νμ ντ t b g γ Z W h

58 matter > antimatter requires physics beyond SM. Standard Model e U d μ c s τ νe νμ ντ t b g γ Z W h + N 1 N2 N3 right-handed neutrino an attractive candidate Leptogenesis [ Fukugita, Yanagida,1986 ] N N (CP violation is essential.) e h ē h

59 Leptogenesis [ Fukugita, Yanagida,1986 ] Result: (I skip all the details of the calculation... For derivations and references, see, e.g., KH: hep-ph/ ) final baryon asymmetry RH s mass heaviest neutrino mass ( atmospheric) wash-out factor (< 1) (calculable: by Boltzmann eq.) effective CP violating phase (observed) 0.8 x It works!! (for MR > GeV). 59

60 Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Dark Energy Particle Physics complicated quark/lepton properties Grand Unified Theory initial condition of Universe Matter > Anti-matter Dark Matter tiny neutrino mass inflation Leptogenesis baryogenesis (heavy) Right- handed neutrino 60

61 Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Dark Energy Particle Physics complicated quark/lepton properties Grand Unified Theory initial condition of Universe Matter > Anti-matter Dark Matter tiny neutrino mass inflation Leptogenesis baryogenesis (heavy) Right- handed neutrino 61

62 Puzzles in our Universe known matter 5% Dark Matter What is DM? 27% Dark Energy 68%

63 Dark Matter We know there is Dark Matter. But we don t know what it is. rotation curve CMB Large scale structure Bullet cluster Credit: X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al. Credit: J.Wise, M. Bradac (Stanford/KIPAC) research/movies/hiresbullet.mov

64 Dark Matter Something beyond the SM is necessary. Standard Model e U d μ c s τ νe νμ ντ t b g γ Z W h None of them can play the role of DM.

65 Dark Matter Something beyond the SM is necessary. Standard Model e U d μ c s τ νe νμ ντ t b g γ Z W h SUSY SUSY particles e U d μ c s τ νe νμ ντ t b g γ Z W h An attractive candidate: SUSY particles Supersymmetry SUSY symmetry between fermions and bosons

66 U c d s t b e μ τ νe νμ ντ U Z γ t b s e μ ν e ν μ ν τ τ W h c d g g Z γ W h 1 sec 380,000 yrs 1.4x1010 yrs SUSY particles were there in the early Universe, and

67 U c d s t b e μ τ νe νμ ντ g Z γ W h χ 1 sec 380,000 yrs 1.4x1010 yrs Eventually, the lightest SUSY particle remains as DM.

68 SUMMARY? Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Particle Physics Grand Unified Theory??? Dark Energy complicated quark/lepton properties initial condition of Universe Matter > Anti-matter Dark Matter Higgs naturalness tiny neutrino mass SUSY inflation Leptogenesis baryogenesis (heavy) Right- handed neutrino and more 68

69 SUMMARY???? Puzzles in the Standard Model = Hints of Physics beyond the Standard Model Cosmology Dark Energy Particle Physics complicated quark/lepton properties Grand Unified Theory initial condition of Universe inflation Matter > Anti-matter Dark Matter Higgs naturalness tiny neutrino mass Leptogenesis baryogenesis SUSY (heavy) Right- handed neutrino maybe completely different scenarios! 69

70 70

71 Leptogenesis [ Fukugita, Yanagida,1986 ] scenario temperature RH s mass step 1: T > MR : N1 are in thermal bath. 71

72 Leptogenesis [ Fukugita, Yanagida,1986 ] scenario temperature RH s mass step 1: T > MR : N1 are in thermal bath. step 2: T MR : N1 decay. (CP violation + out-of-eq.) --> generate Lepton asymmetry, L 0. N N CP violation is essential. e h ē h 72

73 Leptogenesis [ Fukugita, Yanagida,1986 ] scenario temperature RH s mass step 1: T > MR : N1 are in thermal bath. step 2: T MR : N1 decay. (CP violation + out-of-eq.) --> generate Lepton asymmetry, L 0. step 3: Lepton asymmetry Baryon asymmetry L 0 ---> B 0 (automatic in SM! thanks to sphaleron ) [ Kuzmin, Rubakov, Shaposhnikov, 1985 ] 73

74 Leptogenesis [ Fukugita, Yanagida,1986 ] Result: (I skip all the details of the calculation... For derivations and references, see, e.g., KH: hep-ph/ ) final baryon asymmetry RH s mass heaviest neutrino mass ( atmospheric) wash-out factor (< 1) (calculable: by Boltzmann eq.) effective CP violating phase Yukawa Predictable / Calculable in terms of [SM + R.H. ] Lagrangian! 74

75 Leptogenesis [ Fukugita, Yanagida,1986 ] Result: (I skip all the details of the calculation... For derivations and references, see, e.g., KH: hep-ph/ ) final baryon asymmetry RH s mass heaviest neutrino mass ( atmospheric) wash-out factor (< 1) (calculable: by Boltzmann eq.) effective CP violating phase (observed) 0.8 x It works!! (for MR > GeV). 75