Dilepton Production in e−pe^- p and e+e−e^+ e^- Colliders

In an $e^- p$ collider, a striking signature for a dilepton gauge boson is \ep \ ; this cross-section is calculated by using the helicity amplitude technique. At HERA, with center-of-mass energy $\sqrt s = 314 GeV$, a dilepton mass above $150 GeV$ is inaccessible but at LEPII-LHC, with a center-of-mass energy $\sqrt s = 1790 GeV$, masses up to 650 GeV can be discovered. In an $e^+ e^-$ collider, the signature is \ee \ . The cross-sections of this process are also calculated for the center-of-mass energies $\sqrt s = 200, 500$ and $1000 GeV$.Comment: 16 pages, 3 figures (not included), IFP-428-UN

Down for the Count? Getting Reference Counting Back in the Ring

Reference counting and tracing are the two fundamental approaches that have underpinned garbage collection since 1960. However, despite some compelling advantages, reference counting is almost completely ignored in implementations of high performance systems today. In this paper we take a detailed look at reference counting to understand its behavior and to improve its performance. We identify key design choices for reference counting and analyze how the behavior of a wide range of benchmarks might affect design decisions. As far as we are aware, this is the first such quantitative study of reference counting. We use insights gleaned from this analysis to introduce a number of optimizations that significantly improve the performance of reference counting. We find that an existing modern implementation of reference counting has an average 30% overhead compared to tracing, and that in combination, our optimizations are able to completely eliminate that overhead. This brings the performance of reference counting on par with that of a well tuned mark-sweep collector. We keep our in-depth analysis of reference counting as general as possible so that it may be useful to other garbage collector implementers. Our finding that reference counting can be made directly competitive with well tuned mark-sweep should shake the community's prejudices about reference counting and perhaps open new opportunities for exploiting reference counting's strengths, such as localization and immediacy of reclamation

Family Unification, Exotic States and Magnetic Monopoles

The embedding in SU(4)xSU(3)xSU(3) of the well studied gauge groups SU(4)xSU(2)xSU(2) and SU(3)xSU(3)xSU(3) naturally leads to family unification as opposed to simple family replication. An inescapable consequence is the predicted existence of (exotic)color singlet states that carry fractional electric charge. The corresponding magnetic monopoles carry multiple Dirac magnetic charge, can be relatively light (\sim 10^{7}-10^{13}GeV), and may be present in the galaxy not far below the Parker bound.Comment: 10 pages, Late

The ‘Old Western Men’: A Religious Mode of Response to the Conditions of ‘Secular’ Modernity, 1900-1970

This thesis forwards the concept of the ‘Old Western Men’, a phrase borrowed from C. S. Lewis, who used this term to assert the presence of a ‘Great Divide’ in history. Modernity, he believed, was essentially secular, unlike what had preceded it. In this sense, he was in opposition to it as a Christian. This thesis’s unique contribution to the current literature is that it applies Lewis’s identification of the Old Western Men to a broader spectrum of intellectuals and artists, previously referred to, more narrowly, as the ‘Catholic literary revival’. This Ph.D. locates such a revival within a broader ‘religious mode of response’ to modernity, which such men of letters as Lewis believed to be fundamentally materialistic; meaning that modernity denied the existence of an objective spiritual reality. Chapter one describes the general concept of the Old Western Men, including how it confronted secular modernity by attempting to reconcile mind with matter as part of an intellectual via media (middle way); it will also examine the importance that some intellectuals invested in the concept of imaginative understanding. Chapter two focuses on an Old Western emphasis on the ‘More-Than-World’ within the world, one that was essentially sacramental, having come to reconcile reason with the imagination. Chapter three forwards the Old Western notion of thinking ‘christianly’ by cultivating a divine indifference to worldly catastrophe. This also entails examining the concept of self-sanctification, as well as how the Old Western Men responded to the violence of their century by inviting the supernatural into their lives. Chapter four concludes the thesis by examining the spiritual/cultural device of Christendom as a redemptive discourse combatting European nationalism and racialism

Search for Heavy Leptons at Hadron Colliders

Four models are considered which contain heavy leptons beyond the three families of the standard model. Two are fourth-generation extensions of the standard model in which the right-handed heavy leptons are either isosinglets or in an isodoublet; the other two are motivated by the aspon model of CP violation. In all these models, the heavy neutrino can either be heavier than, or comparable in mass to, the charged lepton leading to the possibility that the charged lepton is very long-lived. Production cross section and signatures for the heavy leptons are computed for the SSC and LHC.Comment: 17 pages(8 figures are not included),TRI-PP-92-9

ZZ--Z′Z' mixing and oblique corrections in an SU(3)×U(1){\rm SU(3) \times U(1)} model

A global fit for experiments is included in this revised version.Comment: IFP-460-UNC, TRI-PP-93-11, 20 pages, 2 figures are appende

1999-2000 Alumni Concert

This concert is dedicated to the memory of Nicolas Larin (B.M. 1995)

Prognostic significance of high GFI1 expression in AML of normal karyotype and its association with a FLT3-ITD signature

Abstract Growth Factor Independence 1 (GFI1) is a transcriptional repressor that plays a critical role during both myeloid and lymphoid haematopoietic lineage commitment. Several studies have demonstrated the involvement of GFI1 in haematological malignancies and have suggested that low expression of GFI1 is a negative indicator of disease progression for both myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML). In this study, we have stratified AML patients into those defined as having a normal karyotype (CN-AML). Unlike the overall pattern in AML, those patients with CN-AML have a poorer survival rate when GFI1 expression is high. In this group, high GFI1 expression is paralleled by higher FLT3 expression, and, even when the FLT3 gene is not mutated, exhibit a FLT3-ITD signature of gene expression. Knock-down of GFI1 expression in the human AML Fujioka cell line led to a decrease in the level of FLT3 RNA and protein and to the down regulation of FLT3-ITD signature genes, thus linking two major prognostic indicators for AML