Brookhaven National Laboratory

About: Brookhaven National Laboratory is a facility organization based out in Upton, New York, United States. It is known for research contribution in the topics: Quantum chromodynamics & Scattering. The organization has 18828 authors who have published 39450 publications receiving 1782061 citations. The organization is also known as: BNL.

Comprehensive analysis of data pertaining to the weak neutral current and the intermediate-vector-boson masses.

Abstract: The results of a comprehensive analysis of existing data on the weak neutral current and the W and Z masses are presented. The principal results are the following. (a) There is no evidence for any deviation from the standard model. (b) A global fit to all data yields ${\mathrm{sin}}^{2}$${\mathrm{\ensuremath{\theta}}}_{\mathrm{W}}$\ensuremath{\equiv}1-${\mathrm{M}}_{\mathrm{W}}$${\mathrm{}}^{2}$/${\mathrm{M}}_{\mathrm{Z}}$${\mathrm{}}^{2}$=0.230\ifmmode\pm\else\textpm\fi{}0.0048, where this error and all others given here include full statistical, systematic, and theoretical uncertainties (computed assuming three fermion families, ${m}_{t}$\ensuremath{\le}100 GeV, and ${M}_{H}$\ensuremath{\le}1 TeV). (c) Allowing \ensuremath{\rho}\ensuremath{\equiv}${M}_{W}$${\mathrm{}}^{2}$/(${M}_{Z}$${}^{2}$${\mathrm{cos}}^{2}$${\mathrm{\ensuremath{\theta}}}_{\mathrm{W}}$) as well as ${\mathrm{sin}}^{2}$${\mathrm{\ensuremath{\theta}}}_{\mathrm{W}}$ to vary one obtains ${\mathrm{sin}}^{2}$${\mathrm{\ensuremath{\theta}}}_{\mathrm{W}}$=0.229\ifmmode\pm\else\textpm\fi{}0.0064 and \ensuremath{\rho}=0.998\ifmmode\pm\else\textpm\fi{}0.0086. This implies 90%-confidence-level (C.L.) upper limits of 0.047 and 0.081 for the vacuum expectation values (relative to those of Higgs doublets) for Higgs triplets with weak hypercharge of 0 and \ifmmode\pm\else\textpm\fi{}1, respectively. (d) The parameter ${\ensuremath{\delta}}_{W}$\ensuremath{\equiv}\ensuremath{\Delta}r-\ensuremath{\Delta}${s}^{2}$(1-\ensuremath{\Delta}r)/${\mathrm{sin}}^{2}$${\mathrm{\ensuremath{\theta}}}^{0}$, which is a measure of the radiative corrections relating deep-inelastic neutrino scattering, the W and Z masses, and muon decay, is determined to be 0.112\ifmmode\pm\else\textpm\fi{}0.037. This is consistent with the value ${\ensuremath{\delta}}_{W}$=0.106 expected for ${m}_{t}$=45 GeV and ${M}_{H}$=100 GeV and establishes the existence of radiative corrections at the 3\ensuremath{\sigma} level. (e) The radiative corrections are sensitive to isospin breaking associated with a large ${m}_{t}$.Assuming no deviation from the standard model, consistency of the various reactions requires ${m}_{t}$180 GeV at 90% C.L. for ${M}_{H}$\ensuremath{\le}100 GeV, with a slightly weaker limit for larger ${M}_{H}$. Similar results hold for the mass splittings between fourth-generation quarks or leptons. (f) Most of the parameters in model-independent fits to \ensuremath{ u}q, \ensuremath{ u}e, eq, and ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ processes are now determined uniquely and precisely. (g) Limits are given on the masses and mixing angles of additional Z bosons expected in popular models. For theoretically expected coupling constants one finds that the neutral-current constraints are usually more stringent than the direct-production limits from the CERN Sp\ifmmode\bar\else\textasciimacron\fi{}pS collider, but nevertheless masses as low as 120--300 GeV are typically allowed. (h) The implications of these results for grand unification are discussed. ${\mathrm{sin}}^{2}$${\mathrm{\ensuremath{\theta}}}_{\mathrm{W}}$ is \ensuremath{\ge}2.5 standard deviations above the prediction of minimal SU(5) and similar models for all ${m}_{t}$. It is closer to the prediction of simple supersymmetric grand unified theories but is still somewhat low. (i) The dominant theoretical uncertainty (the charm-quark threshold in deep-inelastic charged-current scattering) is considered in some detail.

Gold nanoparticles enhance the radiation therapy of a murine squamous cell carcinoma.

Abstract: The purpose of this study is to test the hypothesis that gold nanoparticle (AuNP, nanogold)-enhanced radiation therapy (nanogold radiation therapy, NRT) is efficacious when treating the radiation resistant and highly aggressive mouse head and neck squamous cell carcinoma model, SCCVII, and to identify parameters influencing the efficacy of NRT. Subcutaneous (sc) SCCVII leg tumors in mice were irradiated with x-rays at the Brookhaven National Laboratory (BNL) National Synchrotron Light Source (NSLS) with and without prior intravenous (iv) administration of AuNPs. Variables studied included radiation dose, beam energy, temporal fractionation and hyperthermia. AuNP-mediated NRT was shown to be effective for the sc SCCVII model. AuNPs were more effective at 42 Gy than at 30 Gy (both at 68 keV median beam energy) compared to controls without gold. Similarly, at 157 keV median beam energy, 50.6 Gy NRT was more effective than 44 Gy NRT. At the same radiation dose ( approximately 42 Gy), 68 keV was more effective than 157 keV. Hyperthermia and radiation therapy (RT) were synergistic and AuNPs enhanced this synergy, thereby further reducing TCD50 s (tumor control dose 50%) and increasing long-term survivals. It is concluded that gold nanoparticles enhance the radiation therapy of a radioresistant mouse squamous cell carcinoma. The data show that radiation dose, energy and hyperthermia influence efficacy and better define the potential utility of gold nanoparticles for cancer x-ray therapy.

NWChem: Past, present, and future

Abstract: Specialized computational chemistry packages have permanently reshaped the landscape of chemical and materials science by providing tools to support and guide experimental efforts and for the prediction of atomistic and electronic properties. In this regard, electronic structure packages have played a special role by using first-principle-driven methodologies to model complex chemical and materials processes. Over the past few decades, the rapid development of computing technologies and the tremendous increase in computational power have offered a unique chance to study complex transformations using sophisticated and predictive many-body techniques that describe correlated behavior of electrons in molecular and condensed phase systems at different levels of theory. In enabling these simulations, novel parallel algorithms have been able to take advantage of computational resources to address the polynomial scaling of electronic structure methods. In this paper, we briefly review the NWChem computational chemistry suite, including its history, design principles, parallel tools, current capabilities, outreach, and outlook.