Download Experimental Nuclear Physics: Nuclear Astrophysics and Big Bang Nucleosynthesis and more Slides Nuclear Physics in PDF only on Docsity! Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin 1 Lecture 19 Nuclear Astrophysics Baryons, Dark Matter, Dark Energy Experimental Nuclear Physics PHYS 741 heeger@wisc.edu References and Figures from: - Haxton, “Nuclear Astrophysics” - Basdevant, “Fundamentals in Nuclear Physics Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Pheno Seminar this Friday 2 Friday, November 21st, 2008 Phenomenology Seminar Methods to Detect the Cosmic Neutrino Background Time: 2:30 pm Place: 5280 Chamberlin Hall Speaker: Bob McElrath, CERN Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin n/p Ratio as a Function of Temperature 5 n/p ratio Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin He Formation 6 Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Abundances of Light Elements 7 after kT~30KeV nuclear reactions are frozen most neutrons are incorporated into 4HE - Deuterium peaks around 100 seconds after the Big Bang, and is then rapidly swept up into helium nuclei. - A very few helium nuclei combine into heavier nuclei giving a small abundance of Li7 coming from the Big Bang. Note: - H3 decays into He3 with a 12 year half-life so no H3 survives to the present - Be7 decays into Li7 with a 53 day half-life and also does not survive. Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin 10 What are the characteristics of todayʼs Universe? Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin 11 What are the characteristics of todayʼs Universe? - expansion of Universe - visible Universe - baryons - dark matter - photons - neutrinos - the vacuum Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin 12 period of Big Bang Nucleosynthesis Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Occupants of the Universe 15 all data from WMAP except for - photon density (COBE) - lower limit of neutrino density (oscillation data) Possible Models of the Expanding Universe
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Karsten Heeger, Univ. Wisconsin Experimental Nuclear Physics - PHYS741
Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Hubble Diagram 17 - velocities determined by galaxy redshifts - distances determined by a variety of methods (e.g. SN of known luminosity gives phi=L/4PiR^2) Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Rotation Curve of Galaxies: Evidence for Dark Matter 20 Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Rotation Curve of Galaxies: Evidence for Dark Matter 21 Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Rotation Curve of Galaxies: Evidence for Dark Matter 22 Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Observed Spectrum of Cosmic Microwave Background 25 shorter wavelength measurements from balloons, satellites, etc (atmosphere is opaque) Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin 26 Observed Spectrum of Cosmic Microwave Background Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin CMB Multipole Spectrum 27 temperature anisotropies at 10-5 level Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Relic Neutrinos 30 at T ~ 1 MeV (~ 1 sec) neutrinos decouple relic neutrino spectrum left over at T < 1 eV (380,000 yrs, recombination time) photons decouple, cannot break up atoms no more free charges to scatter photons Universe becomes transparent p+e- ↔ H+γ Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Neutrinos and Cosmology very early universe | big bang nucleosynthesis | late time structure formation large-scale structureWMAP enhanced early ISW effect effect on structure formation We see imprints of neutrino mass in the structure of todayʼs Universe … Even small neutrino mass influences power spectrum of galaxy correlations Neutrinos that are more massive cause more clustering on large scales. 31 Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Occupants of the Universe 32 all data from WMAP except for - photon density (COBE) - lower limit of neutrino density (oscillation data) Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Heavy Elements: 0.03% Ghostly Neutrinos: ~0.3% Stars: 0.5% Free Hydrogen and Helium: 0.4% Dark Energy: 70% Dark Matter: 25% Matter in the Universe 35 Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin Formative Events in the Evolution of the Universe 36 Experimental Nuclear Physics - PHYS741Karsten Heeger, Univ. Wisconsin 37