QCD Spin Physics: Partonic Spin Structure of the Nucleon

We discuss some recent developments concerning the nucleon's helicity parton distribution functions: New preliminary data from jet production at RHIC suggest for the first time a non-vanishing polarization of gluons in the nucleon. SIDIS measurements at COMPASS provide better constraints on the strange and light sea quark helicity distributions. Single-longitudinal spin asymmetries in W-boson production have been observed at RHIC and will ultimately give new insights into the light quark and anti-quark helicity structure of the nucleon.Comment: Talk presented at the "International School of Nuclear Physics, 33rd Course: From Quarks and Gluons to Hadrons and Nuclei", Erice, Italy, 16 - 24 September 2011; 12 pages, 9 figure

Extraction of Polarized Gluon Distributions from Large-pt Light Hadron Pair Production

We propose a new formula for extracting the polarized gluon distribution from the large-$p_T$ light hadron pair production for semi-inclusive processes in polarized deep inelastic scattering. In general, a large-$p_T$ hadron pair is produced via photon-gluon fusion(PGF) and QCD Compton at the lowest order of QCD. The PGF gives us a direct information on $\Delta g$ in the nucleon, while QCD Compton becomes background to the signal process for extracting $\Delta g$. We show that the contribution from this background, i.e. the QCD Compton process, can be removed by using symmetry relation among fragmentation functions and taking an appropriate combination of various light hadron pair production processes, and thus the double spin asymmetry can be described in terms of $\Delta g/g$ alone.Comment: 14 pages 3 EPS figures Late

Meson Structure in Deep Inelastic Scattering

We study the deep inelastic structure functions of mesons within the Nambu and Jona-Lasinio model. We calculate the valence quark distributions in $\pi$, $K$, and $\rho$ mesons at the low energy model scale, which are evoluted to the experimental momentum scale in terms of the Altarelli-Parisi equation. The resulting distribution functions show reasonable agreements with experiment. We also discuss the semi-inclusive lepton nucleon scattering process with a slow nucleon in coincidence in the final state, which reveals the off-shell structure of the pion.Comment: 31 pages with 16 figures as uuencoded postscript files, TMU-NT-940101 (plain LaTeX

Probing gluon helicity distribution and quark transversity through hyperon polarization in singly polarized pp collisions

We study the polarization of hyperon in different processes in singly polarized $pp$ collisions, in particular its relation to the polarized parton distributions. We show that by measuring hyperon polarization in particularly chosen processes, one can extract useful information on these parton distributions. We show in particular that, by measuring the $\Sigma^+$ polarization in high $p_T$ direct photon production process, one can extract information on the gluon helicity distribution; and by measuring the transverse polarization of hyeprons with high $p_T$ in singly polarized reactions, one can obtain useful information on the transversity distribution. We present the numerical results obtained for those hyperon polarizations using different models for parton distribution function and those for the spin transfer in fragmentation processes.Comment: 25 pages, 8 figures, to appear in Phys. Rev.

Soft parton radiation in polarized vector boson production: theoretical issues

Accurate measurement of spin-dependent parton distributions in production of electroweak bosons with polarized proton beams at the Relativistic Heavy Ion Collider depends on good understanding of QCD radiation at small transverse momenta $q_T$ of vector bosons. We present a theoretical formalism for small-$q_T$ resummation of the cross sections for production of virtual photons, W, and Z bosons, with the subsequent decay of these bosons into lepton pairs, for arbitrary longitudinal polarizations of the proton beams.Comment: 35 pages, 2 figures; minor modifications; bibliography references adde

Variation in Glycemic Outcomes in Focal Forms of Congenital Hyperinsulinism - The UK Perspective

Context: In focal congenital hyperinsulinism (CHI), localized clonal expansion of pancreatic β-cells causes excess insulin secretion and severe hypoglycemia. Surgery is curative, but not all lesions are amenable to surgery. Objective: We describe surgical and nonsurgical outcomes of focal CHI in a national cohort. Methods: Patients with focal CHI were retrospectively reviewed at 2 specialist centers, 2003-2018. Results: Of 59 patients with focal CHI, 57 had heterozygous mutations in ABCC8/KCNJ11 (51 paternally inherited, 6 de novo). Fluorine-18 L-3,4 dihydroxyphenylalanine positron emission tomography computed tomography scan identified focal lesions in 51 patients. In 5 patients, imaging was inconclusive; the diagnosis was established by frozen section histopathology in 3 patients, a lesion was not identified in 1 patient, and 1 declined surgery. Most patients (n = 56) were unresponsive to diazoxide, of whom 33 were unresponsive or partially responsive to somatostatin receptor analog (SSRA) therapy. Fifty-five patients underwent surgery: 40 had immediate resolution of CHI, 10 had persistent hypoglycemia and a focus was not identified on biopsy in 5. In the 10 patients with persistent hypoglycemia, 7 underwent further surgery with resolution in 4 and ongoing hypoglycemia requiring SSRA in 3. Nine (15% of cohort) patients (1 complex surgical access; 4 biopsy negative; 4 declined surgery) were managed conservatively; medication was discontinued in 8 children at a median (range) age 2.4 (1.5-7.7) years and 1 remains on SSRA at 16 years with improved fasting tolerance and reduction in SSRA dose. Conclusion: Despite a unifying genetic basis of disease, we report inherent heterogeneity in focal CHI patients impacting outcomes of both surgical and medical management

Anomalous Dimension of Dirac's Gauge-Invariant Nonlocal Order Parameter in Ginzburg-Landau Field Theory

In a Ginzburg-Landau theory with $n$ fields, the anomalous dimension of the gauge-invariant nonlocal order parameter defined by the long-distance limit of Dirac's gauge-invariant two-point function is calculated. The result is exact for all $n$ to first order in $\epsilon \equiv 4-d$, and for all $d\in (2,4)$ to first order in $1/n$, and coincides with the previously calculated gauge-dependent exponent in the Landau gauge.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper http://www.physik.fu-berlin.de/~kleinert/35

Evaluating the potential for the environmentally sustainable control of foot and mouth disease in Sub-Saharan Africa

Strategies to control transboundary diseases have in the past generated unintended negative consequences for both the environment and local human populations. Integrating perspectives from across disciplines, including livestock, veterinary and conservation sectors, is necessary for identifying disease control strategies that optimise environmental goods and services at the wildlife-livestock interface. Prompted by the recent development of a global strategy for the control and elimination of foot-and-mouth disease (FMD), this paper seeks insight into the consequences of, and rational options for potential FMD control measures in relation to environmental, conservation and human poverty considerations in Africa. We suggest a more environmentally nuanced process of FMD control that safe-guards the integrity of wild populations and the ecosystem dynamics on which human livelihoods depend while simultaneously improving socio-economic conditions of rural people. In particular, we outline five major issues that need to be considered: 1) improved understanding of the different FMD viral strains and how they circulate between domestic and wildlife populations; 2) an appreciation for the economic value of wildlife for many African countries whose presence might preclude the country from ever achieving an FMD-free status; 3) exploring ways in which livestock production can be improved without compromising wildlife such as implementing commodity-based trading schemes; 4) introducing a participatory approach involving local farmers and the national veterinary services in the control of FMD; and 5) finally the possibility that transfrontier conservation might offer new hope of integrating decision-making at the wildlife-livestock interface

Transverse Polarisation of Quarks in Hadrons

We review the present state of knowledge regarding the transverse polarisation (or transversity) distributions of quarks. After some generalities on transverse polarisation, we formally define the transversity distributions within the framework of a classification of all leading-twist distribution functions. We describe the QCD evolution of transversity at leading and next-to-leading order. A comprehensive treatment of non-perturbative calculations of transversity distributions (within the framework of quark models, lattice QCD and QCD sum rules) is presented. The phenomenology of transversity (in particular, in Drell-Yan processes and semi-inclusive leptoproduction) is discussed in some detail. Finally, the prospects for future measurements are outlined.Comment: small changes, references added, as finally published in Physics Report