1,720,994 research outputs found
Dataset supporting the University of Southampton Doctoral Thesis "Inclusive semileptonic B(s)-meson decays from Lattice QCD"
No full textDataset supporting the Doctoral Thesis "Inclusive semileptonic B(s)-meson decays from Lattice QCD".
Dataset generated to study inclusive (and exclusive) semileptonic processes for B(s) mesons. Results obtained from these data have been published in https://link.springer.com/article/10.1007/JHEP07(2023)145, which represents the key publication of this PhD work.
This dataset contains data corresponding to the two-point, three-point and four-point correlation functions (correlators)
necessary to study the semileptonic decays of Bs mesons in Lattice QCD.
The data are generated through numerical simulations on a 24^3 X 64 Lattice using the ensemble configuration provided by the RBC/UKQCD collaboration.
The thesis provide more details as follows. A generic introduction to Lattice QCD is provided in Chapter 2 of the thesis.
The operators necessary to build the correlation functions for the process considered are discussed in Chapter 4. And the details of the actual simulation are listed in Chapter 5.
The data have been generated with the Grid (https://github.com/paboyle/Grid) and Hadrons (https://github.com/aportelli/Hadrons) software packages using the DiRAC Extreme Scaling service at the University of Edinburgh,
operated by the Edinburgh Parallel Computing Centre on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk).</span
New strategies for probing B→D∗ℓν¯ℓ lattice and experimental data
No full textWe present an analysis of the exclusive semileptonic decay B→D∗ℓν¯ℓ based on the Belle and Belle II data made public in 2023, combined with recent lattice-QCD calculations of the hadronic transition form factors by FNAL/MILC, HPQCD and JLQCD. We also consider a new combination of the Belle and Belle II data sets by HFLAV. The analysis is based on the form-factor parameterisation by Boyd-Grinstein-Lebed (BGL), using Bayesian and frequentist statistics, for which we discuss novel strategies. We compare the results of an analysis where the BGL parameterisation is fit only to the lattice data with those from a simultaneous fit to lattice and experiment, and discuss the resulting predictions for the CKM-matrix element Vcb, as well as other phenomenological observables, such as Rτ/μ(D∗). We find tensions when comparing analyses based on different combinations of experimental or theoretical input, requiring the introduction of a systematic error for some of our results
Dataset for Thesis: Isospin-breaking and all-to-all propagators on the lattice
No full textData set supports: University of Southampton Doctoral Thesis. "Isospin-breaking and all-to-all propagators on the lattice."
After an embargo period, this data will be available on request. Please complete the request form attached</span
The pion vector form factor from lattice QCD and NNLO chiral perturbation theory
No full textWe present a comprehensive study of the electromagnetic form factor, the decay constant and the mass of the pion computed in lattice QCD with two degenerate O(a)-improved Wilson quarks at three different lattice spacings in the range 0.05-0.08fm and pion masses between 280 and 630MeV at mπ L ≥ 4. Using partially twisted boundary conditions and stochastic estimators, we obtain a dense set of precise data points for the form factor at very small momentum transfers, allowing for a model-independent extraction of the charge radius. Chiral Perturbation Theory (ChPT) augmented by terms which model lattice artefacts is then compared to the data. At next-to-leading order the effective theory fails to produce a consistent description of the full set of pion observables but describes the data well when only the decay constant and mass are considered. By contrast, using the next-to-next-to-leading order expressions to perform global fits result in a consistent description of all data. We obtain ⟨r2π⟩ = 0.481(33)(13)fm2 as our final result for the charge radius at the physical point. Our calculation also yields estimates for the pion decay constant in the chiral limit, Fπ/F = 1.080(16)(6), the quark condensate, Σ1/3MSbar (2GeV) = 261(13)(1)MeV and several low-energy constants of SU(2) ChPT
Data for Thesis " and decays in the Continuum Limit of Lattice QCD"
No full textDataset to support Southampton Doctoral Thesis " and decays in the Continuum Limit of Lattice QCD"
The data files are all in the HDF5 format. These can be viewed using the standard HDF5 command-line tools such as h5dump, or opened with reader libraries such as the h5py Python library.
There are three important datasets in each HDF5 file under the root group:
- central: The timeslice-by-timeslice mean of the raw data.
- bs_mean: The timeslice-by-timeslice mean of the Bootstrap samples.
- samples: The Bootstrap samples in a (Configurations X Timeslices)-shaped matrix.
This dataset contains, for the two processes BtoPi and BstoK:
- data/
The full set of 2pt and 3pt correlators used to extract form factors across square lattice momenta n^2=0,1,2,3,4 and across the six ensembles C1, C2, M1, M2, M3, and F1S.
- B/Bs naming convention: [B/Bs]-[ensemble]-[momentum]-[num_smeared].h5 (where num_smeared=0 -> PointPoint, =1 -> PointSmear, =2 -> SmearSmear)
- K/Pi naming convention: [Pi/K]-[ensemble]-[momentum].h5
- 3pt naming convention: [B/Bs]to[Pi/K]_3pt_[t/i]-[ensemble]-[momentum]
- box/
The additional correlators required for the RHQ parameter "box" systematic analysis on the C1 and M2 ensembles. Final-state correlators are duplicates of the ones in the 'data/' directory.
- B/Bs naming convention: [B/Bs]-[ensemble]-[m_b]-[csw]-[zeta]-[momentum]-[num_smeared].h5 (where num_smeared=0 -> PointPoint, =1 -> PointSmear, =2 -> SmearSmear)
- K/Pi naming convention: [Pi/K]-[ensemble]-[momentum].h5
- 3pt naming convention: [B/Bs]to[Pi/K]_3pt_[t/i]-[ensemble]-[m_b]-[csw]-[zeta]-[momentum]
- strange/ (BstoK only)
The additional correlators required for the strange-quark mistuning systematic analysis on the C1 ensemble.
- B/Bs naming convention: [B/Bs]-[ensemble]-[m_s]-[m_b]-[csw]-[zeta]-[momentum]-[num_smeared].h5 (where num_smeared=0 -> PointPoint, =1 -> PointSmear, =2 -> SmearSmear)
- K/Pi naming convention: [Pi/K]-[ensemble]-[m_s]-[momentum].h5
- 3pt naming convention: [B/Bs]to[Pi/K]_3pt_[t/i]-[ensemble]-[m_s]-[m_b]-[csw]-[zeta]-[momentum]</span
K ? ? semileptonic form factor f K?+ (0) on the lattice with 2+1 flavor Domain Wall Fermions
No full textPartially twisted boundary conditions in lattice simulations
No full textWe use chiral perturbation theory to investigate twisted and partially twisted boundary conditions which allow access to momenta other than integer multiples of 2π/L on a lattice with spatial volume L3. For K → ππ decays we show that the breaking of isospin symmetry by the twisted boundary conditions implies that the amplitudes cannot be determined in general. We find numerical evidence for the result that the finite volume effects of the boundary conditions are exponentially suppressed for quantities without final state interactions (meson masses and meson-to-vacuum matrix elements) in a simulation with partial twisting on a sea of Nf = 2 non-perturbatively improved Wilson quarks
Towards a precise lattice determination of the leading hadronic contribution to (g-2)_mu
Full text linkWe report on our computation of the leading hadronic contribution to the anomalous magnetic moment of the muon using two dynamical flavours of non-perturbatively O(a) improved Wilson fermions. The strange quark is introduced in the quenched approximation. Partially twisted boundary conditions are applied to improve the momentum resolution in the relevant integral. Our results, obtained at three different values of the lattice spacing, allow for a preliminary study of discretization effects. We explore a wide range of lattice volumes, namely 2 fm < L < 3 fm, with pion masses from 600 to 280 MeV and discuss different chiral extrapolations to the physical point. We observe a non-trivial dependence of a_mu(HLO) on m_pi especially for small pion masses. The final result, a_mu(HLO)=618(64)*10^(-10), is obtained by considering only the quark connected contribution to the vacuum polarization. We present a detailed analysis of systematic errors and discuss how they can be reduced in future simulations.We report on our computation of the leading hadronic contribution to the anomalous magnetic moment of the muon using two dynamical flavours of non-perturbatively O(a) improved Wilson fermions. The strange quark is introduced in the quenched approximation. Partially twisted boundary conditions are applied to improve the momentum resolution in the relevant integral. Our results, obtained at three different values of the lattice spacing, allow for a preliminary study of discretization effects. We explore a wide range of lattice volumes, namely 2 fm < L < 3 fm, with pion masses from 600 to 280 MeV and discuss different chiral extrapolations to the physical point. We observe a non-trivial dependence of a_mu(HLO) on m_pi especially for small pion masses. The final result, a_mu(HLO)=618(64)*10^(-10), is obtained by considering only the quark connected contribution to the vacuum polarization. We present a detailed analysis of systematic errors and discuss
Nonperturbative infrared finiteness in super-renormalisable scalar quantum field theory -- data release
No full textThis submission contains the Markov-Chain Monte Carlo data required to reproduce central results of the paper "Nonperturbative infrared finiteness in super-renormalisable scalar quantum field theory" (https://arxiv.org/abs/2009.14768). The Python code required to read and analyse the data can be found under https://github.com/andreasjuettner/Finite-Size-Scaling-Analysis (the relevant release is attached to 10.5281/zenodo.4290508). For any questions please get in touch: [email protected].</span
Form factors for semi-leptonic <i>B</i> decays
No full textSemi-leptonic decays provide promising channels to test the Standard Model, search for signs of new physics, or determine fundamental parameters like CKM matrix elements. We present an update on our calculation of short distance contributions to GIM suppressed rare decays focusing in particular on decays. Furthermore we show first results for our calculation of semi-leptonic decays involving transitions. Our calculations are based on RBC-UKQCD's 2+1 flavor domain-wall fermion and Iwasaki gauge field configurations featuring three lattice spacings in the range GeV GeV and pion masses down to the physical value. We calculate the form factors by simulating -quarks using the relativistic heavy quark action, create light and quarks with standard domain-wall kernel, and use optimised M\"obius domain-wall fermions for charm quarks
- …
