Diquarks and Exotic Spectroscopy

We propose that the recently discovered \Theta baryon is a bound state of four quarks and an antiquark, containing two highly correlated ud-pairs. If so, the \Theta baryon has positive parity, and it lies in an near-ideally mixed SU(3)_{f} \mathbf{\bar{10}}_{f} oplus \mathbf{8}_{f}. The Roper resonance and the P_{11}(1710) fit naturally into this classification. We predict an isospin 3/2 multiplet of \Xi's (S=-2) with J^{\Pi}=\half^{+} around 1750 MeV. A search for manifestly exotic \Xi^{+} and \Xi^{--} in this mass range could provide a sharp test of our proposal. We predict that charm and bottom analogues of the \Theta baryon are stable against strong decays.Comment: 5 pages, 2 figures, revtex 4, minor corrections and revisions for journal publicatio

When DEIA Meets Faith in Heightened Tensions: DEIA Initiatives at Catholic-serving Institutions

Copley Library at the University of San Diego launched the Diversity, Equity, Inclusion, and Accessibility (DEIA) Committee in August 2020. The committee was developed in an effort to identify and work through the DEIA-related challenges affecting our country and our local community. Three librarians from the committee endeavored to explore what USD is currently doing as well as how libraries at Catholic-Serving Institutions are providing resources and services in regard to DEIA. Our approach was to survey USD faculty, staff, and administrators who participate or engage in DEIA efforts. The external survey was intended for librarians who work at Catholic-serving Institutions, but not necessarily involved in any kind of DEIA initiative on their campus

alpha^2 corrections to parapositronium decay: a detailed description

We present details of our recent calculation of alpha^2 corrections to the parapositronium decay into two photons. These corrections are rather small and our final result for the parapositronium lifetime agrees well with the most recent measurement. Implications for orthopositronium decays are briefly discussed.Comment: 18 pages, late

A Selection Rule for Multiquark Decays

By assuming SU(6)_cs symmetry for pentaquark decays one finds a selection rule, which strongly reduces the number of states able to decay into a baryon and a meson final state and allows an intriguing identification for the Theta^+ particle recently discovered with the prediction of a narrow width.Comment: 10 pages, no figure

Pricing Bodies: A Feminist New Materialist Approach to the Relations Between the Economic and Socio-Cultural

Arguments that the economic and socio-cultural should be understood as relational and intertwined, and that price involves a reciprocal relationship between the economic and socio-cultural, are increasingly prevalent in the social sciences. I develop these notions of relationality and reciprocation through a feminist new materialist perspective, which emphasises the entanglement of and intra-action between what might usually be seen as independent and autonomous entities. To do this, I focus on a range of recent body-image initiatives, led by government, corporate and non-profit organisations, which aim to improve girls’ and young women’s levels of confidence and self-esteem. I explore how feminist theory tends to see such initiatives in terms of the expansion of the economic sphere into the socio-cultural, which involves a tainting or contamination of embodiment and feeling. Rather than dispute these arguments, I take seriously theories and practices from cultural economy that see the economic and socio-cultural as co-constitutive. I augment these ideas with a feminist new materialist approach and argue that the economic and socio-cultural are in intra-active relations: they do not precede or exist apart from each other. In doing so, I consider how body-image initiatives can be understood as phenomena produced through these entangled intra-active relations, and offer an understanding of pricing as a simultaneously socio-cultural and economic process, where value and values become. I also raise questions regarding how, ethically and politically, boundary making and unmaking can be conceived, and how despite being in entangled relations, asymmetries between economic and socio-cultural relations may be approached

Search for an exotic three-body decay of orthopositronium

We report on a direct search for a three-body decay of the orthopositronium into a photon and two penetrating particles, o-Ps -> gamma + X1 + X2. The existence of this decay could explain the discrepancy between the measured and the predicted values of the orthopositronium decay rate. From the analysis of the collected data a single candidate event is found, consistent with the expected background. This allows to set an upper limit on the branching ratio < 4.4 \times 10^{-5} (at the 90% confidence level), for the photon energy in the range from 40 keV < E_gamma< 400 keV and for mass values in the kinematical range 0 gamma + X1 + X2 decay mode as the origin of the discrepancy.Comment: 9 pages, 3 figure

An analogue of oka’s theorem for weakly normal complex spaces

Two well known results concerning normal complex spaces are the following. First, the singular set of a normal complex space has codimension at least two. Second, this property characterizes normality for complex spaces which are local complete intersections. This second result is a theorem of Abhyankar [1] which generalizes Oka’s theorem. The purpose of this paper is to prove analogues of these facts for the class of weakly normal complex spaces, which were introduced by Andreotti-Norguet [3] in a study of the space of cycles on an algebraic variety. A weakly normal complex space can have singularities in codimension one, but it will be shown that an obvious class of such singularities is generic. © 1977 Pacific Journal of Mathematics. All rights reserved

On the quantization of SU(3)-skyrmions

The quantization condition derived previously for SU(2) solitons quantized with SU(3)-collective coordinates is generalized for SU(3) skyrmions with strangeness content different from zero. Quantization of the dipole-type configuration with large strangeness content found recently is considered as an example.Comment: 7 pages, 2 figures (available by request

A high-resolution record of Southern Ocean intermediate water radiocarbon over the past 30,000 years

The circulation of intermediate waters plays an important role in global heat and carbon transport in the ocean and changes in their distribution are closely tied to glacial–interglacial climate change. Coupled radiocarbon and U/Th measurements on deep-sea Desmophyllum dianthus corals allow for the reconstruction of past intermediate water ventilation. We present a high-resolution time series of Antarctic Intermediate Water radiocarbon from 44 corals spanning 30 ka through the start of the Holocene, encompassing the transition into the Last Glacial Maximum (LGM) and the last deglaciation. Corals were collected south of Tasmania from water depths between 1430 and 1950 m with 80% of them between 1500 and 1700 m, giving us a continuous record from a narrow depth range. The record shows three distinct periods of circulation: the MIS 3–2 transition, the LGM/Heinrich Stadial 1 (extending from ∼22 to 16 kyr BP), and the Antarctic Cold Reversal (ACR). The MIS 3–2 transition and the ACR are characterized by abrupt changes in intermediate water radiocarbon while the LGM time period generally follows the atmosphere at a constant offset, in support of the idea that the LGM ocean was at steady state for its ^(14)C distribution. Closer inspection of the LGM time period reveals a 40‰ jump at ∼19 ka from an atmospheric offset of roughly 230‰ to 190‰, coincident with an observed 10–15 m rise in sea level and a southward shift of the Subantarctic and Polar Fronts, an abrupt change not seen in deeper records. During the ACR time period intermediate water radiocarbon is on average less offset from the atmosphere (∼110‰∼110‰) and much more variable. This variability has been captured within the lifetimes of three individual corals with changes of up to 35‰ over ∼40 yr, likely caused by the movement of Southern Ocean fronts. This surprising result of relatively young and variable intermediate water radiocarbon during the ACR seems to go against the canonical idea of reduced circulation and ventilation in the south during this time period. However comparisons with other records from the Southern Ocean highlight zonal asymmetries, which can explain the deviation of our Tasmanian record from those in Drake Passage and the eastern Pacific. These signals seen in Tasmanian intermediate water Δ^(14)C can also be found in Greenland ice core δ^(18)O and East Asian monsoon strength. Throughout the LGM and the deglaciation, our Tasmanian intermediate water record is sensitive to times when the upper and lower cells of the meridional overturning circulation are more or less interconnected, which has important implications for the global climate system on glacial–interglacial time scales

The role of the Southern Ocean in abrupt transitions and hysteresis in glacial ocean circulation

High‐latitude Northern Hemisphere climate during the last glacial period was characterized by a series of abrupt climate changes, known as Dansgaard‐Oeschger (DO) events, which were recorded in Greenland ice cores as shifts in the oxygen isotopic composition of the ice. These shifts in inferred Northern Hemisphere high‐latitude temperature have been linked to changes in Atlantic meridional overturning strength. The response of ocean overturning circulation to forcing is non‐linear and a hierarchy of models have suggested that it may exist in multiple steady state configurations. Here, we use a time‐dependent coarse‐resolution isopycnal model with four density classes and two basins, linked by a Southern Ocean to explore overturning states and their stability to changes in external parameters. The model exhibits hysteresis in both the steady‐state stratification and overturning strength as a function of the magnitude of North Atlantic Deep Water (NADW) formation. Hysteresis occurs as a result of two non‐linearities in the model‐‐‐the surface buoyancy distribution in the Southern Ocean and the vertical diffusivity profile in the Atlantic and Indo‐Pacific basins. We construct a metric to assess circulation configuration in the model, motivated by observations from the Last Glacial Maximum, which show a different circulation structure from the modern. We find that circulation configuration is primarily determined by NADW density. The model results are used to suggest how ocean conditions may have influenced the pattern of DO events across the last glacial cycle