| 1. |
- Batelaan, M., et al.
(författare)
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Nucleon Form Factors from the Feynman-Hellmann Method in Lattice QCD
- 2022
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- Lattice QCD calculations of the nucleon electromagnetic form factors are of interest at both the high and low momentum transfer regions. For high momentum transfers especially there are open questions which require more intense study, such as the potential zero crossing in the proton's electric form factor. We will present recent progress from the QCDSF/UKQCD/CSSM collaboration on the calculation of these form factors using the Feynman-Hellmann method in lattice QCD. The Feynman-Hellmann method allows for greater control over excited states which we take advantage of by going to high values of the momentum transfer. In this proceeding we present results of the form factors up to 6 GeV2, using Nf = 2 + 1 flavour fermions for three different pion masses in the range 310-470 MeV. The results are extrapolated to the physical pion mass through the use of a flavour breaking expansion.
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| 2. |
- Bickerton, J. M., et al.
(författare)
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Patterns of flavour symmetry breaking in hadron matrix elements involving u, d and s quarks
- 2022
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- Using an SU(3)-flavour symmetry breaking expansion between the strange and light quark masses, we determine how this constrains the extrapolation of baryon octet matrix elements and form factors. In particular we can construct certain combinations, which fan out from the symmetric point (when all the quark masses are degenerate) to the point where the light and strange quarks take their physical values. As a further example we consider the vector amplitude at zero momentum transfer for flavour changing currents.
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| 3. |
- De La Motte, S. A., et al.
(författare)
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Measurements of SU(3) f symmetry breaking in B meson decay constants
- 2022
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- We present updates from QCDSF/UKQCD/CSSM on the SU(3) f breaking in B meson decay constants. The b-quarks are generated with an anisotropic clover-improved action, and are tuned to match properties of the physical B and B∗ mesons. Configurations are generated with m = 1/3(2ml + ms) kept constant to control symmetry breaking effects. Various sources of systematic uncertainty will be discussed, including those from continuum extrapolations and extrapolations to the physical point. We also present new efforts to calculate fB and fBs using weighted averages across multiple time fitting regions. The use of an automated weighted averaging technique over multiple fitting ranges allows for timely tuning of the b-quark and reduces the impact of systematic errors from fitting range biases in calculations of fB and fBs.
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| 4. |
- Hartel, R.W., et al.
(författare)
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Crystallization kinetics for the sucrose-water system
- 1980
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Ingår i: Design, control and analysis of crystallization processes. - : American Institute of Chemical Engineers. ; , s. 65-72
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Konferensbidrag (refereegranskat)abstract
- Crystallization kinetics for the sucrose-water system were studied in a continuous MSMPR cooling crystallizer. Growth and nucleation rates were derived from the measured size distributions using the population balance equation. In the region of higher supersaturation, where secondary nucleation occurs, it appeared that growth was a linear function of supersaturation; whereas, nucleation was approximately 1. 5 order in supersaturation. Growth rates were lower for crystals smaller than about 60 mu m, although these too increased with supersaturation. The latter trends were observed in both the higher (nucleating) and lower (non-nucleating) supersaturation regions. Preliminary batch studies indicated that the rate of secondary nucleation was also a function of both the method of contact and the impact energy.
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| 5. |
- Smail, R. E., et al.
(författare)
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Constraining beyond the standard model nucleon isovector charges
- 2023
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Ingår i: Physical Review D. - : American Physical Society (APS). - 2470-0010 .- 2470-0029. ; 108:9
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Tidskriftsartikel (refereegranskat)abstract
- At the TeV scale, low-energy precision observations of neutron characteristics provide unique probes of novel physics. Precision studies of neutron decay observables are susceptible to beyond the Standard Model (BSM) tensor and scalar interactions, while the neutron electric dipole moment, dn, also has high sensitivity to new BSM CP-violating interactions. To fully utilize the potential of future experimental neutron physics programs, matrix elements of appropriate low-energy effective operators within neutron states must be precisely calculated. We present results from the QCDSF/UKQCD/CSSM Collaboration for the isovector charges gT, gA and gS of the nucleon, ς and Ξ baryons using lattice QCD methods and the Feynman-Hellmann theorem. We use a flavor symmetry breaking method to systematically approach the physical quark mass using ensembles that span five lattice spacings and multiple volumes. We extend this existing flavor-breaking expansion to also account for lattice spacing and finite volume effects in order to quantify all systematic uncertainties. Our final estimates of the nucleon isovector charges are gT=1.010(21)stat(12)sys,gA=1.253(63)stat(41)sys and gS=1.08(21)stat(03)sys renormalized, where appropriate, at μ=2 GeV in the MS¯ scheme.
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| 6. |
- Smail, R. E., et al.
(författare)
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Tensor Charges and their Impact on Physics Beyond the Standard Model
- 2022
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The nucleon tensor charge, gT, is an important quantity in the search for beyond the Standard Model tensor interactions in neutron and nuclear β-decays as well as the contribution of the quark electric dipole moment (EDM) to the neutron EDM. We present results from the QCDSF/UKQCD/CSSM collaboration for the tensor charge, gT, using lattice QCD methods and the Feynman-Hellmann theorem. We use a flavour symmetry breaking method to systematically approach the physical quark mass using ensembles that span three lattice spacings.
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