Showing papers by "TRIUMF published in 2007"
TL;DR: In this article, precise measurements of the spin structure functions of the proton g1p(x,Q2) and deuteron g1d(x and Q2) were presented over the kinematic range 0.0041≤x≤0.9 and 0.18
Abstract: Precise measurements of the spin structure functions of the proton g1p(x,Q2) and deuteron g1d(x,Q2) are presented over the kinematic range 0.0041≤x≤0.9 and 0.18 GeV2≤Q2≤20 GeV2. The data were collected at the HERMES experiment at DESY, in deep-inelastic scattering of 27.6 GeV longitudinally polarized positrons off longitudinally polarized hydrogen and deuterium gas targets internal to the HERA storage ring. The neutron spin structure function g1n is extracted by combining proton and deuteron data. The integrals of g1p,d at Q2=5 GeV2 are evaluated over the measured x range. Neglecting any possible contribution to the g1d integral from the region x≤0.021, a value of 0.330±0.011(theo)±0.025(exp)±0.028(evol) is obtained for the flavor-singlet axial charge a0 in a leading-twist next-to-next-to-leading-order analysis.
301 citations
TL;DR: In this paper, coupled-cluster equations for three-body Hamiltonians are derived in a factorized form that leads to an efficient numerical implementation, and low-momentum two-and three-nucleon interactions are employed to calculate the binding energy of {sup 4}He.
Abstract: We derive coupled-cluster equations for three-body Hamiltonians. The equations for the one- and two-body cluster amplitudes are presented in a factorized form that leads to an efficient numerical implementation. We employ low-momentum two- and three-nucleon interactions and calculate the binding energy of {sup 4}He. The results show that the main contribution of the three-nucleon interaction stems from its density-dependent zero-, one-, and two-body terms that result from the normal ordering of the Hamiltonian in coupled-cluster theory. The residual three-body terms that remain after normal ordering can be neglected.
157 citations
TL;DR: In this paper, a scale-invariant model with dimensionless couplings is proposed, where the shadow Higgs interacts with the standard model through mixing in the scalar sector and kinetic mixing of the gauge bosons.
Abstract: We study a scale-invariant $SU(2)\ifmmode\times\else\texttimes\fi{}U(1{)}_{Y}\ifmmode\times\else\texttimes\fi{}U(1{)}_{s}$ model which has only dimensionless couplings. The shadow $U(1{)}_{s}$ is hidden, and it interacts with the standard model (SM) solely through mixing in the scalar sector and kinetic mixing of the $U(1)$ gauge bosons. The gauge symmetries are broken radiatively by the Coleman-Weinberg mechanism. Lifting of the flat direction in the scalar potential gives rise to a light scalar, the scalon, or the shadow Higgs, and a heavier scalar which we identify as the SM Higgs boson. The phenomenology of this model is discussed. In particular, the constraints on the shadow Higgs in different mass ranges, and the possibility of discovering a shadow Higgs with a mass a few tens of GeV in precision $t$-quark studies at the LHC, are investigated.
149 citations
TL;DR: In this paper, the Sakai-Sugimoto model of holographic QCD at zero temperature and finite chemical potential was studied and it was shown that as the baryon chemical potential is increased above a critical value, there is a phase transition to a nuclear matter phase characterized by a condensate of instantons on the probe Dbranes in the string theory dual.
Abstract: We study the Sakai-Sugimoto model of holographic QCD at zero temperature and finite chemical potential. We find that as the baryon chemical potential is increased above a critical value, there is a phase transition to a nuclear matter phase characterized by a condensate of instantons on the probe D-branes in the string theory dual. As a result of electrostatic interactions between the instantons, this condensate expands towards the UV when the chemical potential is increased, giving a holographic version of the expansion of the Fermi surface. We argue based on properties of instantons that the nuclear matter phase is necessarily inhomogeneous to arbitrarily high density. This suggests an explanation of the "chiral density wave" instability of the quark Fermi surface in large N_c QCD at asymptotically large chemical potential. We study properties of the nuclear matter phase as a function of chemical potential beyond the transition and argue in particular that the model can be used to make a semi-quantitative prediction of the binding energy per nucleon for nuclear matter in ordinary QCD.
146 citations
TL;DR: To investigate the role of the dopamine transporter (DAT) in the regulation of synaptic dopamine levels in Parkinson's disease and its role in the preservation of DA in presynaptic terminals, a DAT-dependent approach is proposed.
Abstract: Objective
To investigate the role of the dopamine transporter (DAT) in the regulation of synaptic dopamine (DA) levels in Parkinson's disease and its role in the preservation of DA in presynaptic terminals.
Methods
Ten Parkinson's disease patients (age, 62.9 ± 9.5 years; Unified Parkinson's Disease Rating Scale motor score in “off” state, 28.5 ± 8.2) underwent positron emission tomography with 11C-methylphenidate (MP, a DAT marker), 11C-dihydrotetrabenazine (a vesicular monoamine transporter 2 marker), and 18F-fluorodopa, leading to the determination of the MP and 11C-dihydrotetrabenazine binding potentials (BPs) and the effective distribution volume for 18F-fluorodopa, the inverse of DA turnover. Seven patients also underwent positron emission tomography with 11C-raclopride before and 1 hour after levodopa administration to estimate levodopa-induced changes in synaptic DA concentration.
Results
We found a significant positive correlation between effective distribution volume and BPMP (r = 0.93; p < 0.001) and a significant negative correlation between changes in synaptic DA concentration and BPMP (r = −0.93; p = 0.04), independent of disease severity and duration.
Interpretation
These data show that in Parkinson's disease, greater DAT levels are directly associated with lower DA turnover and lower changes in synaptic DA concentration. This implies that an important functional role of DAT is to maintain relatively constant synaptic DA levels and to preserve DA in nerve terminals. A decrease in DAT, although potentially serving as a compensatory mechanism in early disease, may ultimately result in increased DA turnover and higher oscillations in synaptic DA concentration, thereby possibly predisposing toward the occurrence of motor complications as disease progresses. Ann Neurol 2007
135 citations
TL;DR: In this article, the authors study the possible origin of neutrino mass in such models, both at tree-level and radiatively, and show that the electroweak Higgs can be interpreted as the pseudo-Goldstone boson of broken scale invariance.
Abstract: Scale invariance may be a classical symmetry which is broken radiatively. This provides a simple way to stabilize the scale of electroweak symmetry breaking against radiative corrections. The simplest phenomenologically successful model of this type involves the addition of one real scalar field to the standard model. In this minimal model the electroweak Higgs can be interpreted as the pseudo-Goldstone boson of broken scale invariance. We study the possible origin of neutrino mass in such models, both at tree-level and radiatively.
131 citations
TL;DR: The D0 Collaboration presents first evidence for the production of single top quarks at the Fermilab Tevatron pp[over ] collider using a 0.9 fb(-1) dataset, and uses the cross section measurement to directly determine the Cabibbo-Kobayashi-Maskawa matrix element that describes the Wtb coupling.
Abstract: The D0 Collaboration presents first evidence for the production of single top quarks at the Fermilab Tevatron collider. Using a 0.9 fb(-1) dataset, we apply a multivariate analysis to separate sig ...
124 citations
TL;DR: The phase I data set of the Sudbury Neutrino Observatory (SNO) as discussed by the authors is based on a 0.65 kt-year exposure of heavy water to the solar 8B neutrino flux.
Abstract: This article provides the complete description of resultsfrom the Phase I data set of the Sudbury Neutrino Observatory (SNO). ThePhase I data set is based on a 0.65 kt-year exposure of heavy water tothe solar 8B neutrino flux. Included here are details of the SNO physicsand detector model, evaluations of systematic uncertainties, andestimates of backgrounds. Also discussed are SNO's approach tostatistical extraction of the signals from the three neutrino reactions(charged current, neutral current, and elastic scattering) and theresults of a search for a day-night asymmetry in the ?e flux. Under theassumption that the 8B spectrum is undistorted, the measurements fromthis phase yield a solar ?e flux of ?(?e) =1.76+0.05?0.05(stat.)+0.09?0.09 (syst.) x 106 cm?2 s?1, and a non-?ecomponent ?(? mu) = 3.41+0.45?0.45(stat.)+0.48?0.45 (syst.) x 106 cm?2s?1. The sum of these components provides a total flux in excellentagreement with the predictions of Standard Solar Models. The day-nightasymmetry in the ?e flux is found to be Ae = 7.0 +- 4.9 (stat.)+1.3?1.2percent (sys.), when the asymmetry in the total flux is constrained to bezero.
122 citations
TL;DR: In this paper, a series of semi-inclusive deepinelastic scattering measurements on deuterium, helium, neon, krypton, and xenon targets has been performed in order to study hadronization.
100 citations
TL;DR: In this paper, the first observation of an azimuthal cross section asymmetry with respect to the charge of the incoming lepton beam is reported from a study of hard exclusive electroproduction of real photons.
Abstract: The first observation of an azimuthal cross section asymmetry with respect to the charge of the incoming lepton beam is reported from a study of hard exclusive electroproduction of real photons. The data have been accumulated by the HERMES experiment at DESY, in which the HERA 27.6 GeV electron or positron beam scattered off an unpolarized hydrogen gas target. The observed asymmetry is attributed to the interference between the Bethe-Heitler process and the deeply virtual Compton scattering (DVCS) process. The interference term is sensitive to DVCS amplitudes, which provide the most direct access to generalized parton distributions. © 2007 The American Physical Society.
91 citations
TL;DR: In this paper, the deuteron and triton potentials were generated using smooth momentum-space regulators as an alternative to a sharp cutoff on relative momenta, which can cause convergence problems at the 10-100 keV level in the deutron and tritons.
TL;DR: This study demonstrates the efficacy of a three-step 64Cu pretargeting procedure for PET imaging of apoptosis and confirms the usefulness of small animal PET to evaluate cancer treatment protocols.
Abstract: In vivo detection of apoptosis is a diagnostic tool with potential clinical applications in cardiology and oncology. Radiolabeled annexin-V (anxV) is an ideal probe for in vivo apoptosis detection owing to its strong affinity for phosphatidylserine (PS), the molecular flag on the surface of apoptotic cells. Most clinical studies performed to visualize apoptosis have used 99mTc-anxV; however, its poor distribution profile often compromises image quality. In this study, tumor apoptosis after therapy was visualized by positron emission tomography (PET) using 64Cu-labeled streptavidin (SAv), following pre-targeting of apoptotic cells with biotinylated anxV. Apoptosis was induced in tumor-bearing mice by photodynamic therapy (PDT) using phthalocyanine dyes as photosensitizers, and red light. After PDT, mice were injected i.v. with biotinylated anxV, followed 2 h later by an avidin chase, and after another 2 h with 64Cu-DOTA-biotin-SAv. PET images were subsequently recorded up to 13 h after PDT. PET images delineated apoptosis in treated tumors as early as 30 min after 64Cu-DOTA-biotin-SAv administration, with tumor-to-background ratios reaching a maximum at 3 h post-injection, i.e., 7 h post-PDT. Omitting the administration of biotinylated anxV or the avidin chase failed to provide a clear PET image, confirming that all three steps are essential for adequate visualization of apoptosis. Furthermore, differences in action mechanisms between photosensitizers that target tumor cells directly or via initial vascular stasis were clearly recognized through differences in tracer uptake patterns detecting early or delayed apoptosis. This study demonstrates the efficacy of a three-step 64Cu pretargeting procedure for PET imaging of apoptosis. Our data also confirm the usefulness of small animal PET to evaluate cancer treatment protocols.
TL;DR: Pten is a key negative regulator of insulin-stimulated glucose uptake in vitro and in vivo and the partial reduction of Pten due to Pten haploinsufficiency is enough to elicit enhanced insulin sensitivity and glucose tolerance in Pten+/− mice.
Abstract: Aims/hypothesis
Insulin controls glucose metabolism via multiple signalling pathways, including the phosphatidylinositol 3-kinase (PI3K) pathway in muscle and adipose tissue. The protein/lipid phosphatase Pten (phosphatase and tensin homologue deleted on chromosome 10) attenuates PI3K signalling by dephosphorylating the phosphatidylinositol 3,4,5-trisphosphate generated by PI3K. The current study was aimed at investigating the effect of haploinsufficiency for Pten on insulin-stimulated glucose uptake.
TL;DR: In this paper, the effects of the peculiar $CP$ conserving phases in unparticle propagators are explored, and it is shown that the phases have a great impact on the violation of the constraint.
Abstract: The effects of the peculiar $CP$ conserving phases in unparticle propagators are explored. We find that the phases have a great impact on $CP$ violation. We adopt the decays ${B}_{d}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${B}_{d}\ensuremath{\rightarrow}{\ensuremath{\ell}}^{\ensuremath{-}}{\ensuremath{\ell}}^{+}$ as the illustrators to demonstrate the influences of these phases on the direct $CP$ asymmetries. In particular, we emphasize that unparticle physics is the only model suggested to date that could give the direct $CP$ asymmetries in ${B}_{d}\ensuremath{\rightarrow}{\ensuremath{\ell}}^{\ensuremath{-}}{\ensuremath{\ell}}^{+}$ as large as 15%. We also point out that the unparticle phases could be probed in $B\ensuremath{\rightarrow}{K}^{*}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ decays by using T-odd correlations.
TL;DR: In this paper, the authors presented ab initio calculations for the two-nucleon low-momentum interactions within coupled-cluster theory, and showed that the convergence with respect to the size of the model space and the single-particle basis can be characterized.
Abstract: We present ab initio calculations for $^{3}\mathrm{H}$, $^{4}\mathrm{He}$, $^{16}\mathrm{O}$, and $^{40}\mathrm{Ca}$ based on two-nucleon low-momentum interactions ${V}_{\mathrm{low}\phantom{\rule{0.3em}{0ex}}k}$ within coupled-cluster theory. For $^{3}\mathrm{H}$ and $^{4}\mathrm{He}$, our results are within 70 and 10 keV of the corresponding Faddeev and Faddeev-Yakubovsky energies. We study in detail the convergence with respect to the size of the model space and the single-particle basis. For the heavier nuclei, we report practically converged binding energies and compare with other approaches.
Rutherford Appleton Laboratory1, University of Glasgow2, Technical University of Dortmund3, Joint Institute for Nuclear Research4, University of London5, CERN6, Spanish National Research Council7, TRIUMF8, University of St. Gallen9, Moscow State University10, Çukurova University11, RWTH Aachen University12, University of Geneva13, Lawrence Berkeley National Laboratory14, Karlsruhe Institute of Technology15, Kyoto University16, Los Alamos National Laboratory17, University College London18, Université catholique de Louvain19, University of Milano-Bicocca20, Russian Academy of Sciences21, Columbia University22, University of Oxford23, Royal Holloway, University of London24, Sapienza University of Rome25, University of Sheffield26, Sofia University27, Bulgarian Academy of Sciences28, University of Sussex29
TL;DR: In this article, the double-differential production cross-section of positive pions, d^2σπ+}/d pdΩ, measured in the HARP experiment is presented.
Abstract: The double-differential production cross-section of positive pions, d^2σ^{π+}/d pdΩ, measured in the HARP experiment is presented. The incident particles are 8.9 GeV/c protons directed onto a beryllium target with a thickness of 5% of a nuclear interaction length. The measured cross-section has a direct impact on the prediction of neutrino fluxes for the MiniBooNE and SciBooNE experiments at Fermilab. After cuts, 13 million protons on target produced about 96000 reconstructed secondary tracks which were used in this analysis. Cross-section results are presented in the kinematic range 0.75 GeV/c≤pπ≤ 6.5 GeV/c and 30 mrad≤θπ≤ 210 mrad in the laboratory frame.
TL;DR: In this article, the antiferromagnetic (AF) nature of the normal spinel was investigated by means of positive muon spin rotation and relaxation techniques using a polycrystalline sample.
Abstract: The antiferromagnetic (AF) nature of the normal spinel ${\mathrm{Co}}_{3}{\mathrm{O}}_{4}$ with N\'eel temperature $({T}_{\mathrm{N}})=30\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ was investigated by means of positive muon spin rotation and relaxation $({\ensuremath{\mu}}^{+}\mathrm{SR})$ techniques using a polycrystalline sample. Clear muon spin precession signals due to a quasistatic long-range AF order were found in the zero-field ${\ensuremath{\mu}}^{+}\mathrm{SR}$ spectra below ${T}_{\mathrm{N}}$. The spectra consist of two oscillating signals with frequencies at $T\ensuremath{\rightarrow}0\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ of 80 and $60\phantom{\rule{0.3em}{0ex}}\mathrm{MHz}$, respectively, indicating an incommensurate (IC) AF order in ${\mathrm{Co}}_{3}{\mathrm{O}}_{4}$. A possible reason for the appearance of the IC-AF order in ${\mathrm{Co}}_{3}{\mathrm{O}}_{4}$ would be local structural transitions due to a charge and/or a spin state change of Co ions.
Massachusetts Institute of Technology1, Argonne National Laboratory2, University of Maryland, College Park3, Florida International University4, Thomas Jefferson National Accelerator Facility5, Hampton University6, Ghent University7, University of the Witwatersrand8, University of Houston9, University of Virginia10, Mississippi State University11, James Madison University12, TRIUMF13, University of Regina14, University of Washington15, Ohio University16, Tohoku University17, University of Basel18, Central Michigan University19, College of William & Mary20, Norfolk State University21, University of Manitoba22
TL;DR: In this article, the authors measured the nuclear transparency of the $A(e,{e}^{\ensuremath{'}}{'})+})$ process in a four momentum transfer squared range from 1.1$ to 4.7$ and showed deviations from traditional nuclear physics expectations and consistent with calculations that include the quantum chromodynamical phenomenon of color transparency.
Abstract: We have measured the nuclear transparency of the $A(e,{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+})$ process in $^{2}\mathrm{H}$, $^{12}\mathrm{C}$, $^{27}\mathrm{Al}$, $^{63}\mathrm{Cu}$, and $^{197}\mathrm{Au}$ targets. These measurements were performed at the Jefferson Laboratory over a four momentum transfer squared range ${Q}^{2}=1.1$ to $4.7\text{ }\text{ }(\mathrm{GeV}/c{)}^{2}$. The nuclear transparency was extracted as the super-ratio of (${\ensuremath{\sigma}}_{A}/{\ensuremath{\sigma}}_{H}$) from data to a model of pion-electroproduction from nuclei without $\ensuremath{\pi}\mathrm{\text{\ensuremath{-}}}N$ final-state interactions. The ${Q}^{2}$ and atomic number dependence of the nuclear transparency both show deviations from traditional nuclear physics expectations and are consistent with calculations that include the quantum chromodynamical phenomenon of color transparency.
TL;DR: In this article, the unparticle phase effects on the direct $CP$ asymmetries in the exclusive decays of the one-loop diagrams were investigated. And they showed that unparticles can significantly enhance the differential branching ratio of $b\ensuremath{\rightarrow}s.
Abstract: Unparticles proposed by Georgi carry $CP$ conserving phases in their propagators. We demonstrate that these peculiar phases have an important impact on $CP$ violation. Without including the strong QCD phases, we study the unparticle phase effects on the direct $CP$ asymmetries in the exclusive decays of ${\overline{B}}_{d}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and $B\ensuremath{\rightarrow}\ensuremath{\pi}K$, in which the flavor changing neutral currents are forbidden at tree level but induced by one-loop diagrams. Interesting and consistent results comparing to the data are obtained. In addition, we find that unparticles will significantly enhance the differential branching ratio of $b\ensuremath{\rightarrow}s{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ at the small invariant mass of ${\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$. The forward-backward asymmetries for $b\ensuremath{\rightarrow}s{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ due to unparticles are also explored.
Lund University1, CERN2, University of Liverpool3, University of Oslo4, TRIUMF5, University of Mainz6, Saha Institute of Nuclear Physics7, University of Cologne8, Ludwig Maximilian University of Munich9, Katholieke Universiteit Leuven10, University of Warsaw11, University of Manchester12, Max Planck Society13, Chalmers University of Technology14, University of Copenhagen15
TL;DR: In this paper, the first excited 2(+) state of the unstable isotope Sn-110 has been studied in safe Coulomb excitation at 2.82 MeV/u using the MINIBALL array at the REX-ISOLDE post accelerator at CERN.
Abstract: The first excited 2(+) state of the unstable isotope Sn-110 has been studied in safe Coulomb excitation at 2.82 MeV/u using the MINIBALL array at the REX-ISOLDE post accelerator at CERN. This is the first measurement of the reduced transition probability of this state using this method for a neutron deficient Sn isotope. The strength of the approach lies in the excellent peak-to-background ratio that is achieved. The extracted reduced transition probability, B(E2 : 0(+) -> 2(+)) 0.220 +/- 0.022e(2) b(2), strengthens the observation of the evolution of the B(E2) values of neutron deficient Sn isotopes that was observed recently in intermediate-energy Coulomb excitation of Sn-108. It implies that the trend of these reduced transition probabilities in the even-even Sn isotopes is not symmetric with respect to the midshell mass number A = 116 as Sn-100 is approached.
TL;DR: The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array.
Abstract: The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau(micro)=2.197 013(24) micros, is in excellent agreement with the previous world average. The new world average tau(micro)=2.197 019(21) micros determines the Fermi constant G(F)=1.166 371(6)x10(-5) GeV-2 (5 ppm). Additionally, the precision measurement of the positive-muon lifetime is needed to determine the nucleon pseudoscalar coupling g(P).
TL;DR: Results are in strong agreement with some of the previously reported literature as well at theoretical calculations for multiple reactions providing for more reliable estimates for the (186)W(p,n)(186)Re reaction.
TL;DR: The magnetism of LixCoO2 (LCO) has been investigated by muon-spin spectroscopy and susceptibility measurements using samples with x=0.1-1 prepared by an electrochemical reaction, suggesting an intermediate- or weak-coupling regime.
Abstract: The magnetism of LixCoO2 (LCO), which has a similar structure to NaxCoO2 (NCO), has been investigated by muon-spin spectroscopy and susceptibility measurements using samples with x=0.1-1 prepared by an electrochemical reaction. In the x range below 0.75, LCO was found to be Pauli paramagnetic down to 1.8 K, suggesting an intermediate- or weak-coupling regime, although disordered local moments, with volume fractions below approximately 20%, appear at low T for LCO with x > or = 0.5. The phase diagram and interactions of LCO are thus strikingly different from NCO, while the differences cannot be explained simply by structural differences between the two systems.
TL;DR: In this article, a measurement of the neutrino asymmetry is presented which represents the first search for new physics using polarized radioactive atoms initially cooled and confined in a magneto-optical trap.
TL;DR: In this article, the beam-spin asymmetry in the azimuthal distribution of pions produced in semi-inclusive deep-inelastic scattering off protons was measured using the HERMES spectrometer.
TL;DR: In this paper, the virial equation of state was extended to include two-and three-nucleon interactions and meson exchange currents, and the energy transfer cross-sections for muon and tau neutrinos at low densities are dominated by the breakdown of loosely-bound $A=3$ and $He$ nuclei.
Abstract: We extend the virial equation of state to include $^{3}\mathrm{H}$ and $^{3}\mathrm{He}$ nuclei, and predict significant mass-three fractions near the neutrinosphere in supernovae. While alpha particles are often more abundant, we demonstrate that energy transfer cross sections for muon and tau neutrinos at low densities are dominated by breakup of the loosely-bound $^{3}\mathrm{H}$ and $^{3}\mathrm{He}$ nuclei. The virial coefficients involving $A=3$ nuclei are calculated directly from the corresponding nucleon-$^{3}\mathrm{H}$ and nucleon-$^{3}\mathrm{He}$ scattering phase shifts. For the neutral-current inelastic cross sections and the energy transfer cross sections, we perform ab initio calculations based on microscopic two- and three-nucleon interactions and meson-exchange currents.
TL;DR: These data confirm the expectation that a 6-OHDA lesion does not affect the affinity and confirm the feasibility of in vivo Scatchard analysis in rats; a much simpler binding potential (BP) measure can thus be used as a marker of lesion severity (LS) in this rat model of Parkinson's disease.
Abstract: This is the first in vivo determination of the vesicular monoamine transporter (VMAT2) density (Bmax) and ligand–transporter affinity (Kdapp) in six unilaterally 6-hydroxydopamine (6-OHDA) lesioned rats using micro-positron emission tomography (PET) imaging with [11C]-(+)-α-dihydrotetrabenazine (DTBZ). A multiple ligand concentration transporter assay (MLCTA) was used to determine a Bmax value of 178 ± 32 pmol/mL and a Kdapp of 47.7 ± 9.3 pmol/mL for the non-lesioned side and 30.52 ± 5.84 and 43.4 ± 15.52 pmol/mL for the lesioned side, respectively. While Bmax was significantly different between the two sides, no significant difference was observed for the Kdapp. In addition to demonstrating the feasibility of in vivo Scatchard analysis in rats, these data confirm the expectation that a 6-OHDA lesion does not affect the affinity; a much simpler binding potential (BP) measure can thus be used as a marker of lesion severity (LS) in this rat model of Parkinson's disease. A transporter occupancy curve demonst...
TL;DR: In this article, the authors studied a model in which lepton number violation is triggered by a dimension 4 hard breaking term in the scalar potential, and they constructed a minimal model, which contains a SU(2) triplet with hypercharge Y=2 and a pair of singlet doubly charged scalar fields in addition to the standard model Higgs doublet.
Abstract: We study a model in which lepton number violation is solely triggered by a dimension 4 hard breaking term in the scalar potential. A minimal model, which contains a SU(2) triplet with hypercharge Y=2 and a pair of singlet doubly charged scalar fields in addition to the standard model (SM) Higgs doublet, is constructed. The model is technically natural in the sense that lepton number is preserved in the limit that the hard term vanishes. SM phenomenology restricts the vacuum expectation value of the triplet scalar field v{sub T}<5.78 GeV. Neutrino masses controlled by v{sub T} are generated at the two loop level and are naturally in the sub-eV range. In general they exhibit normal hierarchy structure. Here the neutrino mass term does not dominate neutrinoless double beta decays of nuclei. Instead the short-distance physics with doubly charged Higgs exchange gives the leading contribution. We expect weak scale singly and doubly charged Higgs bosons to make their appearances at the LHC and the ILC.
TL;DR: In this article, the Poincare group defined over symplectic manifolds is derived in phase space and the Noether theorem is derived using an interacting field, including a gauge field.
TL;DR: The appearance of a bump is discussed in the realm of the [ K ¯ 3 N ] clustering process in nuclei in this paper, where the authors show that Λ-hyperons and deuterons are preferentially emitted in opposite directions.