The Top Quark: Experimental Roots and Branches of Theory

The CDF and D0 experiments at the Fermilab Tevatron have discovered the top quark and provided first measurements of many of its properties. The small top sample gathered by Run I leaves open many possibilities for top physics beyond the standard model. Run II and the LHC (and eventually an LC) promise to deepen our knowledge of the top quark and its relationship to electroweak symmetry breaking.Comment: 14 pages, 9 figures; talk presented at HCP200

Anomalous Gluon Self-Interactions and ttˉt \bar{t} Production

Strong-interaction physics that lies beyond the standard model may conveniently be described by an effective Lagrangian. The only genuinely gluonic CP-conserving term at dimension six is the three-gluon-field-strength operator $G^3$. This operator, which alters the 3-gluon and 4-gluon vertices form their standard model forms, turns out to be difficult to detect in final states containing light jets. Its effects on top quark pair production hold the greatest promise of visibility.Comment: Latex file using [aps,aipbook,floats,epsf]{revtex}. 12 pages, 4 Postscript figures. Full PS copy at http://smyrd.bu.edu/htfigs/htfigs.html Talk presented by EHS at the International Symposium on Vector Boson Self-Interactions, UCLA, Feb. 1-3, 199

Correcting Market Failure Due to Interdependent Preferences: When Is Piecemeal Policy Possible?

Generally, implementation of Pigovian taxes to correct for market failure requires an enormous set of information. For each commodity-person combination a different tax is required to correct the resulting market inefficiency. In this paper, we analyse interdependent preferences and inefficiency of the market solution with the aim of finding conditions justifying simple rules for such taxes. We examine the utility possibility curve and Scitovsky community indifference curve, allowing for general utility interdependence and agent heterogeneity. In particular we show the equivalence of taxes derived from the Marshallian and compensated demand approaches. We move on to analyse the welfare cost of consumption externalities and show that it decomposes into part due to individuals choosing suboptimal quantities and part due to individuals using valuations that are not socially optimal. We show what forms of externality can justify simple policy corrections. In particular, we analyse the conditions which are required for the market failure to be corrected by: 1) specific indirect ad valorem taxes on commodities, 2) the same proportional tax rate on every commodity, 3) a proportional income tax rate on each individual. The conditions are related to the restrictions necessary to have H synthetic consumers without externalities who replicate behaviour of individuals with externalities. An example with two individuals and three goods concludes the paper.Consumption externalities; Piecemeal policy

A narrative analysis of new mothers' experiences of not-understanding

As Counselling Psychologists, we often help clients engage with experiences which feel significant but unresolved. What is this like for people, and how do they respond? This study explores peoples’ narrative engagement with this psychological situation, termed ‘not-understanding’, as they arose during the transition to motherhood. The secondary aim was to interrogate the role of narrative in such experiences. Existing models articulate automatic responses to meaning discrepancies, orders of meanings made, and measurements associated with the presence or absence of meaning in life. Less is understood about the phenomenology of living with an unresolved experience. Transition to motherhood has been associated with uncertainty and discrepancies between expectations and experience, however, the psychological implications of this aspect of transition are not well understood. An experiential narrative analysis was conducted to explore experiences of not-understanding, including participants’ narrative engagement with such experiences. Semi-structured interviews with eight first time mothers at six-twelve months postpartum were analysed using an interpretative perspective-taking framework adapted from Critical Narrative Analysis (Langdridge, 2007)., interrogating both what was said and how it was said. Experiences, including infant feeding decisions and childbirth, were explored where they had remained, for a time, not-understood. Engagement with not-understanding was directed, for example, towards the need to avoid feared phenomena, bear witness, negotiate a decision’s meaning, or re-establish connection with others. Not-understanding was therefore an active, valuable psychological space in its own right, shaped by context and appraisals of vulnerability. Narration was found to be the means of both expressing and negotiating potential interpretations of the meaning of the not-understood experiences. The findings challenge those psychological models and maternal discourses which view unresolvedness primarily as a sign of a pathology, incompetence, or meaning discrepancy. Exploring, valuing and nurturing people’s capacity for standing in not-understanding, may help them to engage more authentically with values and choices

Research Factsheet: Woodfuel experiment - North Thurlbar, Newton Rigg

An experiment has been set up to assess the economic viability and environmental impacts of woodfuel harvesting in North Thurlbar, a small wood land on the University of Cumbria Newton Rigg campus estate. This factsheet describes the aim of the study and the experiment design

Testing Extended Technicolor With RbR_b

We review the connection between $m_t$ and the $Zb\bar b$ vertex in ETC models and demonstrate the power of the resulting experimental constraint on models with weak-singlet ETC bosons. Some efforts to bring ETC models into agreement with experimental data on the $Zb\bar b$ vertex are mentioned, and the most promising one (non-commuting ETC) is discussed in detail.Comment: Talk given by E.H. Simmons at the Yukawa International Seminar `95 in Kyoto, 21-26 August, 1995 and at the International Symposium on Heavy Flavor and Electroweak Theory in Beijing, 17-19 August, 1995. Latex (uses PTPTeX.sty and epsf). 9 pages. 1 figure. Full postscript version available at http://smyrd.bu.edu/ . (minor typos corrected

Symmetric Laplacians, Quantum Density Matrices and their Von-Neumann Entropy

We show that the (normalized) symmetric Laplacian of a simple graph can be obtained from the partial trace over a pure bipartite quantum state that resides in a bipartite Hilbert space (one part corresponding to the vertices, the other corresponding to the edges). This suggests an interpretation of the symmetric Laplacian's Von Neumann entropy as a measure of bipartite entanglement present between the two parts of the state. We then study extreme values for a connected graph's generalized R\'enyi-$p$ entropy. Specifically, we show that (1) the complete graph achieves maximum entropy, (2) the $2$-regular graph: a) achieves minimum R\'enyi-$2$ entropy among all $k$-regular graphs, b) is within $\log 4/3$ of the minimum R\'enyi-$2$ entropy and $\log4\sqrt{2}/3$ of the minimum Von Neumann entropy among all connected graphs, c) achieves a Von Neumann entropy less than the star graph. Point $(2)$ contrasts sharply with similar work applied to (normalized) combinatorial Laplacians, where it has been shown that the star graph almost always achieves minimum Von Neumann entropy. In this work we find that the star graph achieves maximum entropy in the limit as the number of vertices grows without bound. Keywords: Symmetric; Laplacian; Quantum; Entropy; Bounds; R\'enyi