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Astronomy Colloquium: "A Bitter Pill--The Primordial Lithium Problem"

Event Type
Astronomy Department
Astronomy 134
Jan 28, 2014   3:45 pm  
Brian Fields
Originating Calendar
Astronomy Colloquium Speaker Calendar

Primordial nucleosynthesis describes the production of the lightest

elements in the first three minutes of cosmic time.  We will discuss

the transformative influence of the WMAP and Planck

determinations of the cosmic baryon density.  Coupled with

nucleosynthesis theory, these measurements make tight predictions for

the primordial light element abundances: deuterium observations agree

spectacularly with these predictions, helium observations are in good

agreement, but lithium observations (in metal-poor halo stars) are

significantly discrepant--this is the "lithium problem.''  Over the

past decade, the lithium discrepancy has become more severe, and very

recently the solution space has shrunk.  A solution due to new nuclear

resonances has now been essentially ruled out experimentally.  Stellar

evolution solutions remain viable but must be finely tuned.

Observational systematics are now being probed by qualitatively new

methods of lithium observation.  Finally, new physics solutions

are now strongly constrained by the combination of the

precision baryon determination by Planck, and the need to match

the D/H abundances now measured to unprecedented precision at high


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