The retention of americium and plutonium on six commercially available extraction chromatographic resins was investigated in the presence of various concentrations of calcium. Results of batch study ...experiments showed that there was no significant interference due to calcium for the adsorption of plutonium or americium from both nitric and hydrochloric acid on the majority of the extraction chromatographic resins studied. However, the retention of americium on DGA resin from nitric acid decreased by over two orders of magnitude when calcium was introduced into the system. DGA was found to have a capacity for calcium of 4.53 ± 0.08 mg Ca g
−1
DGA resin.
The retention of
239
Pu and
241
Am on six commercially available extraction chromatographic resins was investigated to determine the effect of matrix constituents commonly found within sea and ocean ...water on their uptake. It was found that the retention of
239
Pu and
241
Am on almost all of the resins from either nitric acid or hydrochloric acid system was not significantly affected by matrix constituents in artificial ocean water. However, the retention of
241
Am on DGA resin from nitric acid was found to be reduced by over two orders of magnitude in the presence of artificial ocean water.
We present a determination of the charm-quark mass in the MS¯ scheme using the data combination of charm production cross section measurements in deep-inelastic scattering at HERA. The framework of ...global analyses of the proton structure accounts for all correlations of the charm-quark mass with the other non-perturbative parameters, most importantly the gluon distribution function in the proton and the strong coupling constant αs(MZ). We obtain at next-to-leading order in QCD the value mc(mc)=1.15±0.04(exp)−0.00+0.04(scale) GeV and at approximate next-to-next-to-leading order mc(mc)=1.24±0.03(exp)−0.02+0.03(scale)−0.07+0.00(theory) GeV with an accuracy competitive with other methods.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A combination is presented of all inclusive deep inelastic cross sections previously published by the H1 and ZEUS ...collaborations at HERA for neutral and charged current ... scattering for zero beam polarisation. The data were taken at proton beam energies of 920, 820, 575 and 460 GeV and an electron beam energy of 27.5 GeV. The data correspond to an integrated luminosity of about 1 fb... and span six orders of magnitude in negative four-momentum-transfer squared, ..., and Bjorken x. The correlations of the systematic uncertainties were evaluated and taken into account for the combination. The combined cross sections were input to QCD analyses at leading order, next-to-leading order and at next-to-next-to-leading order, providing a new set of parton distribution functions, called HERAPDF2.0. In addition to the experimental uncertainties, model and parameterisation uncertainties were assessed for these parton distribution functions. Variants of HERAPDF2.0 with an alternative gluon parameterisation, HERAPDF2.0AG, and using fixed-flavour-number schemes, HERAPDF2.0FF, are presented. The analysis was extended by including HERA data on charm and jet production, resulting in the variant HERAPDF2.0Jets. The inclusion of jet-production cross sections made a simultaneous determination of these parton distributions and the strong coupling constant possible, resulting in ... An extraction of ... and results on electroweak unification and scaling violations are also presented.
A combination is presented of all inclusive deep inelastic cross sections previously published by the H1 and ZEUS collaborations at HERA for neutral and charged current $e^{\pm}p$ scattering for zero ...beam polarisation. The data were taken at proton beam energies of 920, 820, 575 and 460 GeV and an electron beam energy of 27.5 GeV. The data correspond to an integrated luminosity of about 1 fb$^{-1}$ and span six orders of magnitude in negative four-momentum-transfer squared, $Q^2$, and Bjorken $x$. The correlations of the systematic uncertainties were evaluated and taken into account for the combination. The combined cross sections were input to QCD analyses at leading order, next-to-leading order and at next-to-next-to-leading order, providing a new set of parton distribution functions, called HERAPDF2.0. In addition to the experimental uncertainties, model and parameterisation uncertainties were assessed for these parton distribution functions. Variants of HERAPDF2.0 with an alternative gluon parameterisation, HERAPDF2.0AG, and using fixed-flavour-number schemes, HERAPDF2.0FF, are presented. The analysis was extended by including HERA data on charm and jet production, resulting in the variant HERAPDF2.0Jets. The inclusion of jet-production cross sections made a simultaneous determination of these parton distributions and the strong coupling constant possible, resulting in $\alpha_s(M_Z)=0.1183 \pm 0.0009 {\rm(exp)} \pm 0.0005{\rm (model/parameterisation)} \pm 0.0012{\rm (hadronisation)} ^{+0.0037}_{-0.0030}{\rm (scale)}$. An extraction of $xF_3^{\gamma Z}$ and results on electroweak unification and scaling violations are also presented.
Construction of a modular large-area neutron detector for the NSCL Baumann, T.; Boike, J.; Brown, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2005, Letnik:
543, Številka:
2
Journal Article
Recenzirano
A collaboration of ten institutions, including a large number of undergraduate schools, proposed and constructed a highly efficient large-area neutron detector. The modular neutron array (MoNA) is ...designed to detect high-energy neutrons in experiments with fast rare isotopes at the National Superconducting Cyclotron Laboratory. It consists of 144 individual detector modules of plastic scintillator, is position sensitive, and features multi-hit capability. The MoNA project involves undergraduate students from the collaborating colleges and universities and gives them the possibility to take part in research at the forefront of nuclear physics.
HERAFitter Alekhin, S.; Behnke, O.; Belov, P. ...
The European physical journal. C, Particles and fields,
07/2015, Letnik:
75, Številka:
7
Journal Article
Recenzirano
Odprti dostop
HERAFitter is an open-source package that provides a framework for the determination of the parton distribution functions (PDFs) of the proton and for many different kinds of analyses in Quantum ...Chromodynamics (QCD). It encodes results from a wide range of experimental measurements in lepton–proton deep inelastic scattering and proton–proton (proton–antiproton) collisions at hadron colliders. These are complemented with a variety of theoretical options for calculating PDF-dependent cross section predictions corresponding to the measurements. The framework covers a large number of the existing methods and schemes used for PDF determination. The data and theoretical predictions are brought together through numerous methodological options for carrying out PDF fits and plotting tools to help to visualise the results. While primarily based on the approach of collinear factorisation, HERAFitter also provides facilities for fits of dipole models and transverse-momentum dependent PDFs. The package can be used to study the impact of new precise measurements from hadron colliders. This paper describes the general structure of HERAFitter and its wide choice of options.
HERAFitter Alekhin, S; Behnke, O; Belov, P ...
The European physical journal. C, Particles and fields,
07/2015, Letnik:
75, Številka:
7
Journal Article
Recenzirano
Odprti dostop
HERAFitter is an open-source package that provides a framework for the determination of the parton distribution functions (PDFs) of the proton and for many different kinds of analyses in Quantum ...Chromodynamics (QCD). It encodes results from a wide range of experimental measurements in lepton-proton deep inelastic scattering and proton-proton (proton-antiproton) collisions at hadron colliders. These are complemented with a variety of theoretical options for calculating PDF-dependent cross section predictions corresponding to the measurements. The framework covers a large number of the existing methods and schemes used for PDF determination. The data and theoretical predictions are brought together through numerous methodological options for carrying out PDF fits and plotting tools to help to visualise the results. While primarily based on the approach of collinear factorisation, HERAFitter also provides facilities for fits of dipole models and transverse-momentum dependent PDFs. The package can be used to study the impact of new precise measurements from hadron colliders. This paper describes the general structure of HERAFitter and its wide choice of options.
Cross sections for elastic and proton-dissociative photoproduction of
J
/
ψ
mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at
ep
...centre-of-mass energies
and
, corresponding to integrated luminosities of
and
, respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25<
W
γp
<110 GeV. Differential cross sections d
σ
/d
t
, where
t
is the squared four-momentum transfer at the proton vertex, are measured in the range |
t
|<1.2 GeV
2
for the elastic process and |
t
|<8 GeV
2
for proton dissociation. The results are compared to other measurements. The
W
γp
and
t
-dependences are parametrised using phenomenological fits.
PDF
