750 GeV Diphotons from a D3-brane

Motivated by the recently reported diphoton excess at 750 GeV observed by both CMS and ATLAS, we study string-based particle physics models which can accommodate this signal. Quite remarkably, although Grand Unified Theories in F-theory tend to impose tight restrictions on candidate extra sectors, the case of a probe D3-brane near an E-type Yukawa point naturally leads to a class of strongly coupled models capable of accommodating the observed signature. In these models, the visible sector is realized by intersecting 7-branes, and the 750 GeV resonance is a scalar modulus associated with motion of the D3-brane in the direction transverse to the Standard Model 7-branes. Integrating out heavy 3-7 string messenger states leads to dimension five operators for gluon fusion production and diphoton decays. Due to the unified structure of interactions, these models also predict that there should be additional decay channels to ZZ and Z gamma. We also comment on models with distorted unification, where both the production mechanism and decay channels can differ.Comment: v3: 12 pages, 1 figure, clarifications adde

Particle Physics Implications of F-theory

We review recent progress in realizing Grand Unified Theories (GUTs) in a strongly coupled formulation of type IIB string theory known as F-theory. Our main emphasis is on the expected low-energy phenomenology of a minimal class of F-theory GUTs. We introduce the primary ingredients in such constructions, and then present qualitative features of GUT models in this framework such as GUT breaking, doublet-triplet splitting, and proton decay. Next, we review proposals for realizing flavor hierarchies in the quark and lepton sectors. We discuss possible supersymmetry breaking scenarios, and their consequences for experiment, as well as geometrically minimal realizations of F-theory GUTs which incorporate most of these features.Comment: v2: 42 pages, 3 figures, submitted to Annu. Rev. Nuc. Part. Sci, improved formatting and small clarification

The Economics, Technology and Neuroscience of Human Capability Formation

This paper begins the synthesis of two currently unrelated literatures: the human capital approach to health economics and the economics of cognitive and noncognitive skill formation. A lifecycle investment framework is the foundation for understanding the origins of human inequality and for devising policies to reduce it.

China's Investment in Human Capital

This paper discusses evidence on human capital investment in China. Policies through the mid 1990s favor physical investment over schooling.

The Case for Investing in Disadvantaged Young Children

Bildung, Kinder, Pädagogik, Bildungspolitik, Bildungsinvestition, Education, Children, Education sciences, Educational policy, Human capital investment

The American Family in Black and White: A Post-Racial Strategy for Improving Skills to Promote Equality

In contemporary America, racial gaps in achievement are primarily due to gaps in skills. Skill gaps emerge early before children enter school. Families are major producers of those skills. Inequality in performance in school is strongly linked to inequality in family environments. Schools do little to reduce or enlarge the gaps in skills that are present when children enter school. Parenting matters, and the true measure of child advantage and disadvantage is the quality of parenting received. A growing fraction of American children across all race and ethnic groups is being raised in dysfunctional families. Investment in the early lives of children in disadvantaged families will help close achievement gaps. America currently relies too much on schools and adolescent remediation strategies to solve problems that start in the preschool years. Policy should prevent rather than remediate. Voluntary, culturally sensitive support for parenting is a politically and economically palatable strategy that addresses problems common to all racial and ethnic groups.skill gap, racial inequality, early childhood intervention

The Impact of Government on the Economic Status of Black Americans

This paper reviews recent evidence on black economic progress. It notes that while relative status increased over the period 1965-1981, absolute differentials in real earnings between blacks and whites widened over this period. The paper goes out to summarize recent studies of the impact of government on the economic status of black Americans. Educational policy has a strong effect. The evidence on affirmative action programs is mixed. There is an intrinsic bias in the methods used toward finding no effect of affirmative action programs. Selection bias effects do not account for more than 10-12% of measured wage growth of black males.