Experimental Nuclear Physics: Nuclear Astrophysics and Big Bang Nucleosynthesis, Slides of Nuclear Physics

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 r pele te ee ed a beter) < lyme et Pete ely Bele mS 5 > Ke 5 P ha fl ra A decelerating universe reaches its current size in the least amount of time. The universe could eventually contract and collapse into a "big crunch" or expand indefinitely. A coasting universe (center) is older than a decelerating universe because it takes more time to oC ee Re Bole ee eae (right) is older still. The rate of expansion actually increases because CE Me Role Rae ec Choe 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