Renwick James Hudspith
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Research Interests
Renwick James Hudspith has a total of 274 co-authors. Here are the top co-authors by number of shared publications:
- Kim Maltman
York University
14 shared publications - Randy Lewis
Department of Physics and Astronomy York University M3J 1P3 Toronto Ontario Canada
14 shared publications - Anthony Francis
National yang Ming Chiao Tung University
7 shared publications - Nicolas Garron
Liverpool Hope University
6 shared publications - Peter A. Boyle
University of Edinburgh
5 shared publications - Harvey B. Meyer
Johannes Gutenberg-Universität Mainz
4 shared publications
Latest Publications
- Top Cited PapersOpen Access
- 10 September 2025
- Published by Elsevier in Physics Reports
- Vol. 1143, 1-158
The anomalous magnetic moment of the muon in the Standard Model: an update
- 10 September 2025
- Published by Elsevier in Physics Reports
- Vol. 1143, 1-158
Top Cited PapersOpen AccessThe anomalous magnetic moment of the muon in the Standard Model: an update
- Open Access
- 27 December 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 110 (11)
Hot QCD matter around the chiral crossover: A lattice study with -improved Wilson fermionsUsing lattice QCD simulations with O ( a ) -improved Wilson quarks and physical up, down, and strange quark masses, we investigate the properties of thermal QCD matter at the temperatures T = { 128 , 154 , 192 } MeV with a fixed lattice spacing a = 0.064 fm and volume V = ( 6.1 fm ) 3 . We find that the pion quasiparticle, defined as the low-energy pole in the two-point function of the axial charge, becomes lighter as the temperature increases, and we give an argument based on hydrodynamics as to why the pole becomes purely diffusive above the chiral crossover. We study the thermal modification of the isovector vector spectral function using the Backus-Gilbert method, finding an enhancement at low energies and a depletion at energies around 1 GeV. The analogous study of the axial-vector channel reveals a larger enhancement at energies below 1 GeV, and we show that these findings are consistent with rigorous spectral sum rules. The difference between vector and axial-vector correlators, an order parameter for chiral symmetry, turns out to be overall suppressed by more than an order of magnitude at the crossover. Published by the American Physical Society 2024
- 27 December 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 110 (11)
Open AccessHot QCD matter around the chiral crossover: A lattice study with -improved Wilson fermionsUsing lattice QCD simulations with O ( a ) -improved Wilson quarks and physical up, down, and strange quark masses, we investigate the properties of thermal QCD matter at the temperatures T = { 128 , 154 , 192 } MeV with a fixed lattice spacing a = 0.064 fm and volume V = ( 6.1 fm ) 3 . We find that the pion quasiparticle, defined as the low-energy pole in the two-point function of the axial charge, becomes lighter as the temperature increases, and we give an argument based on hydrodynamics as to why the pole becomes purely diffusive above the chiral crossover. We study the thermal modification of the isovector vector spectral function using the Backus-Gilbert method, finding an enhancement at low energies and a depletion at energies around 1 GeV. The analogous study of the axial-vector channel reveals a larger enhancement at energies below 1 GeV, and we show that these findings are consistent with rigorous spectral sum rules. The difference between vector and axial-vector correlators, an order parameter for chiral symmetry, turns out to be overall suppressed by more than an order of magnitude at the crossover. Published by the American Physical Society 2024
- Open Access
- 25 November 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 110 (9)
QCD in the chiral SU(3) limit from baryon masses on lattice QCD ensembles
The baryon masses on Coordinate Lattice Simulations (CLS) ensembles are used to determine the Low-Energy Constants (LEC) that characterize quantum chromodynamics in the flavor-SU(3) limit with vanishing up, down, and strange quark masses. Here we reevaluate some of the baryon masses on flavor-symmetric ensembles with much-improved statistical precision, in particular for the decuplet states. These additional results then lead to a more significant chiral extrapolation of the lattice dataset to its chiral SU(3) limit. Our results are based on the chiral Lagrangian with baryon octet and decuplet fields considered at the one-loop level. Finite-box and discretization effects of the lattice data are considered systematically. While in our global fit of the data we insist on large- N c sum rules for the LEC that enter at N 3 LO , all other LEC are unconstrained. In particular, we obtain values for the chiral limit of the pion decay constant and the isospin-limit of the quark-mass ratio compatible with the FLAG report. Published by the American Physical Society 2024
- 25 November 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 110 (9)
Open AccessQCD in the chiral SU(3) limit from baryon masses on lattice QCD ensembles
The baryon masses on Coordinate Lattice Simulations (CLS) ensembles are used to determine the Low-Energy Constants (LEC) that characterize quantum chromodynamics in the flavor-SU(3) limit with vanishing up, down, and strange quark masses. Here we reevaluate some of the baryon masses on flavor-symmetric ensembles with much-improved statistical precision, in particular for the decuplet states. These additional results then lead to a more significant chiral extrapolation of the lattice dataset to its chiral SU(3) limit. Our results are based on the chiral Lagrangian with baryon octet and decuplet fields considered at the one-loop level. Finite-box and discretization effects of the lattice data are considered systematically. While in our global fit of the data we insist on large- N c sum rules for the LEC that enter at N 3 LO , all other LEC are unconstrained. In particular, we obtain values for the chiral limit of the pion decay constant and the isospin-limit of the quark-mass ratio compatible with the FLAG report. Published by the American Physical Society 2024
- Open Access
- 7 November 2024
- Published by Sissa Medialab Srl
- Vol. 443, 024
Exotic Spectroscopy: A Lattice QCD perspective
We review recent results for exotic states with beauty quarks from Lattice QCD, focusing on heavy-light tetraquarks. In particular, there is a growing consensus of deeply-bound, strong-interaction stable $T_{bb}$ and $T_{bbs}$ four-quark states. Beyond these the possibility of further bound states where either the light quarks are made heavier, or the heavy quarks lighter are being explored, such as possible $T_{bc}$ and $T_{bs}$ bound states. We also compare predictions for positive-parity $B_s$-mesons, which, in analogy to the $D_{s0}^*(2317)$ and $D_{s1}(2460)$, may feature a large four-quark component. We conclude by briefly discussing searches for other heavy multi-quark states.- 7 November 2024
- Published by Sissa Medialab Srl
- Vol. 443, 024
Open AccessExotic Spectroscopy: A Lattice QCD perspective
We review recent results for exotic states with beauty quarks from Lattice QCD, focusing on heavy-light tetraquarks. In particular, there is a growing consensus of deeply-bound, strong-interaction stable $T_{bb}$ and $T_{bbs}$ four-quark states. Beyond these the possibility of further bound states where either the light quarks are made heavier, or the heavy quarks lighter are being explored, such as possible $T_{bc}$ and $T_{bs}$ bound states. We also compare predictions for positive-parity $B_s$-mesons, which, in analogy to the $D_{s0}^*(2317)$ and $D_{s1}(2460)$, may feature a large four-quark component. We conclude by briefly discussing searches for other heavy multi-quark states. - Open Access
- 6 November 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 110 (9)
Improved analysis of strong-interaction-stable doubly bottom tetraquarks on the lattice
We update earlier lattice results for the binding energies of the flavor antitriplet of strong-interaction-stable doubly bottom, J P = 1 + tetraquarks, employing an extended sink construction which produces significantly improved ground-state effective-mass plateaus, as well as new, larger-volume ensembles which reduce possible finite-volume effects at lighter pion masses. The updated bindings are 115(17) MeV for the I = 0 member of the antitriplet and 47(8) MeV for its I = 1 / 2 partner. We also provide an update of our earlier study of the variable heavy mass dependence of binding in the 1 + channel and new results on this dependence for binding in the 0 + channel, accessible when the two heavy quarks have unequal masses. Implications of these results of potential relevance to experimental searches for signals of the production of doubly bottom tetraquarks and/or a possible bottom-charm partner of the T c c are also discussed. Published by the American Physical Society 2024
- 6 November 2024
- Published by American Physical Society (APS) in Physical Review D
- Vol. 110 (9)
Open AccessImproved analysis of strong-interaction-stable doubly bottom tetraquarks on the lattice
We update earlier lattice results for the binding energies of the flavor antitriplet of strong-interaction-stable doubly bottom, J P = 1 + tetraquarks, employing an extended sink construction which produces significantly improved ground-state effective-mass plateaus, as well as new, larger-volume ensembles which reduce possible finite-volume effects at lighter pion masses. The updated bindings are 115(17) MeV for the I = 0 member of the antitriplet and 47(8) MeV for its I = 1 / 2 partner. We also provide an update of our earlier study of the variable heavy mass dependence of binding in the 1 + channel and new results on this dependence for binding in the 0 + channel, accessible when the two heavy quarks have unequal masses. Implications of these results of potential relevance to experimental searches for signals of the production of doubly bottom tetraquarks and/or a possible bottom-charm partner of the T c c are also discussed. Published by the American Physical Society 2024
- Open Access
Quark mass dependence of doubly heavy tetraquark binding
The existence of bound doubly heavy tetraquark states was confirmed by the recent LHCb discovery of the doubly charmed $T_{cc}$, less than 1 MeV below the meson pair threshold. Others states with two heavy (bottom or charm) quarks could also be bound, perhaps more deeply. Here we discuss our previous work, and the improvements in our current, updated analysis of various heavy-heavy-light-light tetraquark candidates, including the light and heavy quark mass dependence of the binding.Open AccessQuark mass dependence of doubly heavy tetraquark binding
The existence of bound doubly heavy tetraquark states was confirmed by the recent LHCb discovery of the doubly charmed $T_{cc}$, less than 1 MeV below the meson pair threshold. Others states with two heavy (bottom or charm) quarks could also be bound, perhaps more deeply. Here we discuss our previous work, and the improvements in our current, updated analysis of various heavy-heavy-light-light tetraquark candidates, including the light and heavy quark mass dependence of the binding. - Open Access
- 16 June 2023
- Published by American Physical Society (APS) in Physical Review D
- Vol. 107 (11) , 114510
Exotic tetraquark states with two quarks and and states in a nonperturbatively tuned lattice NRQCD setupWe use Wilson-clover gauge-field ensembles from the Coordinated Lattice Simulations (CLS) Consortium in a lattice nonrelativistic QCD (NRQCD) setup to predict the binding energy of an tetraquark and a tetraquark. We determine the binding energies with respect to the relevant and thresholds, respectively, to be 112.0(13.2) MeV for the , and 46.4(12.3) MeV for the . We also determine the ground-state and mesons to lie 75.4(14.0) and 78.7(13.9) MeV below the and thresholds, respectively. Our errors are entirely dominated by systematics due to discretization effects. To achieve these measurements, we performed a neural network based nonperturbative tuning of the lattice NRQCD Hamiltonian’s parameters against the basic bottomonium spectrum. For all lattice spacings considered we can reproduce the continuum splittings of low-lying bottomonia. It is worth remarking that our nonperturbative tuning parameters deviate from 1 by significant amounts, particularly the term .- 16 June 2023
- Published by American Physical Society (APS) in Physical Review D
- Vol. 107 (11) , 114510
Open AccessExotic tetraquark states with two quarks and and states in a nonperturbatively tuned lattice NRQCD setupWe use Wilson-clover gauge-field ensembles from the Coordinated Lattice Simulations (CLS) Consortium in a lattice nonrelativistic QCD (NRQCD) setup to predict the binding energy of an tetraquark and a tetraquark. We determine the binding energies with respect to the relevant and thresholds, respectively, to be 112.0(13.2) MeV for the , and 46.4(12.3) MeV for the . We also determine the ground-state and mesons to lie 75.4(14.0) and 78.7(13.9) MeV below the and thresholds, respectively. Our errors are entirely dominated by systematics due to discretization effects. To achieve these measurements, we performed a neural network based nonperturbative tuning of the lattice NRQCD Hamiltonian’s parameters against the basic bottomonium spectrum. For all lattice spacings considered we can reproduce the continuum splittings of low-lying bottomonia. It is worth remarking that our nonperturbative tuning parameters deviate from 1 by significant amounts, particularly the term . - Open Access
- 11 April 2023
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2023 (4) , 1-88
Hadronic light-by-light scattering contribution to the muon g − 2 from lattice QCD: semi-analytical calculation of the QED kernel
Hadronic light-by-light scattering is one of the virtual processes that causes the gyromagnetic factor g of the muon to deviate from the value of two predicted by Dirac’s theory. This process makes one of the largest contributions to the uncertainty of the Standard Model prediction for the muon (g − 2). Lattice QCD allows for a first-principles approach to computing this non-perturbative effect. In order to avoid power-law finite-size artifacts generated by virtual photons in lattice simulations, we follow a coordinate-space approach involving a weighted integral over the vertices of the QCD four-point function of the electromagnetic current carried by the quarks. Here we present in detail the semi-analytical calculation of the QED part of the amplitude, employing position-space perturbation theory in continuous, infinite four-dimensional Euclidean space. We also provide some useful information about a computer code for the numerical implementation of our approach that has been made public at https://github.com/RJHudspith/KQED.
- 11 April 2023
- Published by Springer Nature in Journal of High Energy Physics
- Vol. 2023 (4) , 1-88
Open AccessHadronic light-by-light scattering contribution to the muon g − 2 from lattice QCD: semi-analytical calculation of the QED kernel
Hadronic light-by-light scattering is one of the virtual processes that causes the gyromagnetic factor g of the muon to deviate from the value of two predicted by Dirac’s theory. This process makes one of the largest contributions to the uncertainty of the Standard Model prediction for the muon (g − 2). Lattice QCD allows for a first-principles approach to computing this non-perturbative effect. In order to avoid power-law finite-size artifacts generated by virtual photons in lattice simulations, we follow a coordinate-space approach involving a weighted integral over the vertices of the QCD four-point function of the electromagnetic current carried by the quarks. Here we present in detail the semi-analytical calculation of the QED part of the amplitude, employing position-space perturbation theory in continuous, infinite four-dimensional Euclidean space. We also provide some useful information about a computer code for the numerical implementation of our approach that has been made public at https://github.com/RJHudspith/KQED.
- Open AccessExotic Tetraquark states with two $\bar{b}$-quarks and $J^P=0^+$ and $1^+$ $B_s$ states in a nonperturbatively-tuned Lattice NRQCD setupWe use $n_f=2+1$ Wilson-clover gauge-field ensembles from the CLS consortium in a Lattice NRQCD setup to predict the binding energy of a $I(J^P)=0(1^+)$ $ud\bar{b}\bar{b}$ tetraquark and a $\frac{1}{2}(1^+)$ $\ell s\bar{b}\bar{b}$ tetraquark. We determine the binding energies with respect to the relevant $BB^*$ and $B_sB^*$ thresholds respectively to be $112.0(13.2)$ MeV for the $ud\bar{b}\bar{b}$, and $46.4(12.3)$ MeV for the $\ell s\bar{b}\bar{b}$. We also determine the ground-state $J^P=0^+$ $B_{s0}^*$ and $1^+$ $B_{s1}$ mesons to lie $75.4(14.0)$ and $78.7(13.9)$ MeV below the $BK$ and $B^*K$ thresholds respectively. Our errors are entirely dominated by systematics due to discretisation effects. To achieve these measurements, we performed a neural network based nonperturbative tuning of the Lattice NRQCD Hamiltonian's parameters against the basic bottomonium spectrum. For all lattice spacings considered we can reproduce the continuum splittings of low-lying bottomonia. It is worth remarking that our nonperturbative tuning parameters deviate from 1 by significant amounts, particularly the term $c_2$.Open AccessExotic Tetraquark states with two $\bar{b}$-quarks and $J^P=0^+$ and $1^+$ $B_s$ states in a nonperturbatively-tuned Lattice NRQCD setupWe use $n_f=2+1$ Wilson-clover gauge-field ensembles from the CLS consortium in a Lattice NRQCD setup to predict the binding energy of a $I(J^P)=0(1^+)$ $ud\bar{b}\bar{b}$ tetraquark and a $\frac{1}{2}(1^+)$ $\ell s\bar{b}\bar{b}$ tetraquark. We determine the binding energies with respect to the relevant $BB^*$ and $B_sB^*$ thresholds respectively to be $112.0(13.2)$ MeV for the $ud\bar{b}\bar{b}$, and $46.4(12.3)$ MeV for the $\ell s\bar{b}\bar{b}$. We also determine the ground-state $J^P=0^+$ $B_{s0}^*$ and $1^+$ $B_{s1}$ mesons to lie $75.4(14.0)$ and $78.7(13.9)$ MeV below the $BK$ and $B^*K$ thresholds respectively. Our errors are entirely dominated by systematics due to discretisation effects. To achieve these measurements, we performed a neural network based nonperturbative tuning of the Lattice NRQCD Hamiltonian's parameters against the basic bottomonium spectrum. For all lattice spacings considered we can reproduce the continuum splittings of low-lying bottomonia. It is worth remarking that our nonperturbative tuning parameters deviate from 1 by significant amounts, particularly the term $c_2$.
- Open Access
- 30 January 2023
- Published by Sissa Medialab Srl
- Vol. 430, 061
Non-perturbative heavy quark action tuning using machine learning
We present a fully non-perturbative determination of a relativistic heavy quark action’s parameters on the CLS $n_f=2+1$ Wilson-clover ensembles using neural networks. We then further illustrate the applicability of such an approach for lattice NRQCD bottom quarks, and finally investigate some physics quantities under our tuning. In particular, we look at the excited spectrum of bottomonia, a popular $ud\bar{b}\bar{b}$ tetraquark candidate, and the not-yet observed bottom-strange cousins of the exotic $J^P=0^+$ $D_{s0}^*(2317)$ and $J^P=1^+$ $D_{s1}(2460)$ mesons.- 30 January 2023
- Published by Sissa Medialab Srl
- Vol. 430, 061
Open AccessNon-perturbative heavy quark action tuning using machine learning
We present a fully non-perturbative determination of a relativistic heavy quark action’s parameters on the CLS $n_f=2+1$ Wilson-clover ensembles using neural networks. We then further illustrate the applicability of such an approach for lattice NRQCD bottom quarks, and finally investigate some physics quantities under our tuning. In particular, we look at the excited spectrum of bottomonia, a popular $ud\bar{b}\bar{b}$ tetraquark candidate, and the not-yet observed bottom-strange cousins of the exotic $J^P=0^+$ $D_{s0}^*(2317)$ and $J^P=1^+$ $D_{s1}(2460)$ mesons.