THINGS BIG & SMALL Dhiman Chakraborty ([email protected]) Outline:

THINGS BIG & SMALL Dhiman Chakraborty (dhiman@fnal.gov) Outline:

THINGS BIG & SMALL Dhiman Chakraborty ([email protected]) Outline: Part 2 Up to the grandest: the Universe at large Big Bang Cosmology: a brief overview The three tests of BB cosmology Cosmic Microwave Background (CMB) Flat Universe Large Scale Structure (LSS) Dark matter Expansion of the Universe: Supernova 1a (SN1a) Dark E Recent/current/proposed experimental programs using ground- and space-based telescopes: CMB: COBE, WMAP, Planck LSS: HST, SDSS, LSST, Chandra, XMM-Newton,

SN1a: HZSNT, SCP, SNAP Summary of planned HEP & cosmology projects Outlook Dhiman Chakraborty THINGS BIG AND SMALL 2 Up to the grandest Dhiman Chakraborty THINGS BIG AND SMALL 3

Big Bang cosmology t=0: the beginning of time & space represents an essential singularity with infinite matter-energy density () and temperature (T). An expansion ensues, governed primarily by GTR. T & fall as the universe expands. Dhiman Chakraborty THINGS BIG AND SMALL 4 Epochs & dominant components

? : <10 s; string (?) -43 Inflation: 10-38 s; vacuum (inflaton driven?) Quantum fluctuations imprinted on metric, to be seen later as anisotropies in cosmic microwave background. Baryogenesis: 10-36 s; radiation/matter(?) WIMP decoupling Big Bang Nucleosynthesis (BBN): 1 s; radiation neutrino decoupling. Best tested part, nB/n only parameter. Cosmic Microwave Background (CMB): 1012 s; matter photon decoupling transition to matter-dominated era. Present: 51017 s; vacuum

Dark energy drives the universe into accelerated expansion. Dhiman Chakraborty THINGS BIG AND SMALL 5 Evolution of the Universe Dhiman Chakraborty THINGS BIG AND SMALL 6 Evolution of the Universe

Time The state of the Universe Human Since the Big Bang Equivalent 379,000 years This is a time when the pattern of the Cosmic Microwave Background light was set. The Universe was just cool enough for atoms to form for the first time. At this stage, the Universe is the equivalent of a baby

just 19 hours old. 200 million years The matter in the Universe condensed by gravity until the first stars ignited. WMAP has detected this event at about 200 million years after the Big Bang. (WMAP does not see the light of the first stars directly, but has detected a polarized signal that is the tell-tale signature of the energy released by the first stars.) The Universe is the equivalent of a baby of 13 months, just old enough to begin taking its first steps.

1 billion years The first galaxies began to form at about this time. Unlike a human child, the Universe has reached the end of its formative years at this young age. There are no further notable cosmic events past this stage. At this age, the Universe is equivalent to a child just under six years old. 13.7 billion years

The present day Universe with its billions upon billions of stars and galaxies is found to be 13.7 billion years old, an age with a margin of error of close to 1 percent. An adult person at 80. Dhiman Chakraborty THINGS BIG AND SMALL 7 Pillars of the Big Bang theory Cosmic microwave background

Abundance of the light elements Evidence of cosmic expansion Observationally, these measurements are completely independent of each other. They must provide even support for the theory to hold water. Dhiman Chakraborty THINGS BIG AND SMALL 8 Hubbles law Based on experimental observation (1929): On average, all galaxies are moving away from each other with speed proportional to

distance. Corollary: on large scales, the universe is homogeneous and isotropic- it looks the same in all directions and in all parts theres no center nor edge. Metric for a homogeneous & isotropic universe: (s ) 2 (t ) 2 R 2 (t )((x) 2 (y ) 2 (z ) 2 ) R(t): scale factor (dimensionless) Dhiman Chakraborty THINGS BIG AND SMALL 9 The Friedman k 8G

equation H where 2 N R2 3 R 1 , R0 1 z

- governs the expansion of a uniform gas-filled universe = Energy density (matter+radiation+vacuum) - z t (large z small t, present R = R0 z=0 ). - H0 60 km/s/Megaparsec (1 Mpc 3.26 light-year) 3H 2 c : critical density ( k=0, flat 8GN universe) obs emit (1 z ) Dhiman Chakraborty : Red shift (Doppler effect)

THINGS BIG AND SMALL 10 The density components In general, ( R ) R 3(1 w ) ( z ) 0 (1 z ) 3(1 w ) p w : equation of state parameter

In a flat universe dominated by: 3 M ( z ) 0 (1 z ) Matter: w=0 Radiation: w=1/3 Vacuum: w=-1 ( z ) 0 (1 z ) ( z ) 0 4 i : density parameter (i=normal matter, i c neutrino, dark matter, dark energy, ) Dhiman Chakraborty

THINGS BIG AND SMALL 11 Geometry of the Universe i i Current data = 1 Dhiman Chakraborty THINGS BIG AND SMALL 12 Structure formation

Jeans instability in self-gravitating systems cause formation of structures. Needs initial seed density fluctuations. Density fluctuations grow little in a radiation- or vacuum-dominated universe. Density fluctuations grow linearly in a matter -dominated universe. Baryonic matter alone falls far short of explaining the level of structure seen today. Dhiman Chakraborty THINGS BIG AND SMALL 13 Theoretical arguments for dark matter

Spiral galaxies made of bulge+disk: unstable as a self-gravitating system need a (nearly) spherical halo. With only baryons as matter, structure formation starts too late for us to exist at this time Matter-radiation equality achieved too late, Baryon density fluct. cant grow until decoupling, Need larger electrically neutral component. Dhiman Chakraborty THINGS BIG AND SMALL 14 Size-evolution of the universe Dhiman Chakraborty

THINGS BIG AND SMALL 15 Observational verification A Standard Model of cosmology emerges from extensive surveys of: Anisotropy in cosmic microwave background (earliest structures visible, z 3000): CMB Large-scale structures (e.g. Galaxies, clusters, grav. lensing, z 5, dark matter,): LSS

Type 1a supernova brightness & redshift (std. candles, z 0.5, dark energy): SN1a Each gives a linear equation in M, any two of these determine M, ; the 3rd serves as a crosscheck. Dhiman Chakraborty THINGS BIG AND SMALL 16 CMB: Peeking into the universes infancy with the Wilkinson Microwave Anisotropy Probe Dhiman Chakraborty

THINGS BIG AND SMALL 17 WMAP talk about thermal resolution! Dhiman Chakraborty THINGS BIG AND SMALL 18 WMAP talk about spatial

resolution! Dhiman Chakraborty THINGS BIG AND SMALL 19 LSS: Surveying galaxies & clusters with normal (HST, SDSS) & x-ray (Chandra, XMMNewton) vision Dhiman Chakraborty THINGS BIG AND SMALL The XMM-Newton x-ray observatory

20 LSS: Dark matter in galaxy clusters Galaxies form clusters bound in a gravitational well. Hydrogen gas in the well gets heated, emits x-ray. Allows us to determine the baryon fraction of the cluster. Dhiman Chakraborty THINGS BIG AND SMALL

21 LSS: Chandra discovers "Rivers Of Gravity" that define the cosmic landscape Four independent teams of scientists have detected intergalactic gas with temperatures in the range 300,000 to 5 million degrees Celsius by observing quasars with the Chandra X-ray Observatory. An artist's rendering illustrates how X-rays from a distant quasar dim as they pass through a cloud of the intergalactic gas. By measuring the amount of dimming due to oxygen and other elements in the cloud - see the spectrum of the quasar PKS 2155-304 in the inset - astronomers were able to estimate the

temperature, density and mass of the absorbing gas cloud. Dhiman Chakraborty THINGS BIG AND SMALL 22 LSS: Chandra discovers "Rivers Of Gravity" that define the cosmic landscape Dhiman Chakraborty THINGS BIG AND SMALL 23

LSS: Surveying galaxies & clusters with normal (HST, SDSS) & x-ray (Chandra, XMMNewton) vision The sky is not so dark in x-ray: HST (L), Chandra (R) Dhiman Chakraborty THINGS BIG AND SMALL 24 Sloan Digital Sky Survey (SDSS) Dhiman Chakraborty THINGS BIG AND SMALL

25 LSS The M78 nebula, a nursery of stars, as seen by SDSS It is extremely important to know how the mass and energy, most of it dark, is distributed throughout the universe. A particle theory

that contradicts cosmological observations will not be viable. Dhiman Chakraborty THINGS BIG AND SMALL 26 LSS & CMB surveys agree Dhiman Chakraborty THINGS BIG AND SMALL 27

SN1a: measuring the rate of cosmic expansion using high-z supernovae 1a as standard candles Nuclear chain reaction in stars with M2Msun (more complex - binaries etc.) As bright as host galaxy Brightness not const, but related to fall-off rate. Apparent brightness gives distance. Red shift (z) gives relative radial velocity. Dhiman Chakraborty

THINGS BIG AND SMALL 28 SN1a: Clear evidence of accelerated expansion By SCP+HZSNT using HST & ground-based telescopes. The cosmological constant fits the bill. Can in principle be something else with ve p. Generally called Dark Energy. Dhiman Chakraborty

THINGS BIG AND SMALL 29 Expansion history of the universe Dhiman Chakraborty THINGS BIG AND SMALL 30 SN1a: Next step: the Joint Dark Energy Mission

The proposed Supernova/ Acceleration Probe (SNAP) Dhiman Chakraborty THINGS BIG AND SMALL 31 The cosmic concordance CMB:

1 flat universe. LSS: M 0.3 Remarkable agreement SN1a: -2 M 0.1 Dark Matter: 23% 4% Dark Energy: 73% 4% (Baryons: 4% 0.4%, Neutrinos: ~0.5%) Remarkable precision (~10%) Dhiman Chakraborty THINGS BIG AND SMALL Remarkable

results 32 Cosmology summary: The current state of knowledge: The Universe is geometrically flat, It is expanding with increasing speed, Dark energy dominates matter, Dark matter dominates baryonic matter, Baryonic matter dominates baryonic antimatter. Dhiman Chakraborty THINGS BIG AND SMALL 33

Outstanding questions: Dark Matter: What is it? How is it distributed? Dark Energy: What is it? Why not ~ 10120? Why not = 0? Does it evolve? Baryons: Why not B 0? Ultra-High-Energy Cosmic Rays: What are they? Where do they come from? What tools do we need to address these? Dhiman Chakraborty THINGS BIG AND SMALL 34 Particle dark matter

Suppose an elementary particle constitutes DM WIMP (Weakly Interacting Massive Particle). Heavy but stable, neutral, produced in early Universe. Left over from near-complete annihilation. No such candidate in the SM, must be new physics! TeV is the right energy scale. SUSY: the lightest supersymmetric particle (LSP) is a superpartner of a gauge boson in most models: the bino is a perfect candidate for a WIMP. There are other possibilities (axino, gravitino, axion,

technibaryons, axion, Kaluza-Klein particles, ) In any case, we should be able to produce such WIMPs at colliders of the next generation (LHC, ILC). Dhiman Chakraborty THINGS BIG AND SMALL 35 Neutralino dark matter Dhiman Chakraborty THINGS BIG AND SMALL 36 The enigma of dark energy

A nave estimate of the cosmological constant in quantum field theory MPlanck410120 times the onserved value. The worst prediction in theoretical physics! People had argued that there must be some mechanism to set it to zero. But now it seems finite!!! Quintessence? A scalar field slowly rolling down the potential hill. Will set to 0 when it reaches the minimum? Must be extremely light: O(10-42 GeV) !!! Dhiman Chakraborty THINGS BIG AND SMALL 37

Particle physics at the energy frontier Dhiman Chakraborty THINGS BIG AND SMALL 38 The many connections Dhiman Chakraborty THINGS BIG AND SMALL 39 Conclusions

Theres mounting evidence for non-baryonic dark matter and dark energy. These immediately imply physics beyond the SM. Dark matter is likely to be at TeV scale. Search for dark matter using Collider experiments (LHC, ILC) Direct searches (CDMS-II) Indirect searches (ICECUBE) Dark energy best investigated by JDEM (SNAP?). Dhiman Chakraborty THINGS BIG AND SMALL 40 The larger US efforts

From the report of the Quantum Universe subcommittee commissioned by HEPAP (DOE/NSF) Dhiman Chakraborty THINGS BIG AND SMALL 41 The smaller US efforts From the report of the Quantum Universe subcommittee commissioned by HEPAP (DOE/NSF) Dhiman Chakraborty THINGS BIG AND SMALL

42 HEPAP recommendation to DOE/NSF (by subpanel on Long Range Planning for U.S. HEP) Dhiman Chakraborty THINGS BIG AND SMALL 43 Outlook A large number of particle physics, astrophysics, and cosmology projects both theoretical and experimental are underway. They complement

each other toward a common goal to solve the most fundamental mysteries of nature. It is a truly INTERNATIONAL effort. We are living through a revolution in our understanding of the Universe on both the smallest and the largest scales. The next decade or two will usher us into a new era of observation and comprehension. Dhiman Chakraborty THINGS BIG AND SMALL 44 THANK YOU! Feel free to contact the speaker

for more information [email protected] Dhiman Chakraborty THINGS BIG AND SMALL 45

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