arXiv subjects

Arnau Beltran

Publications and source records attributed to Arnau Beltran.

3 recordsLinked to original sources

arXiv2026

Higher-order hadronic vacuum polarization contribution to the muon $g-2$ from lattice QCD

We present the first lattice QCD calculation of the next-to-leading order hadronic vacuum polarization contribution to the muon anomalous magnetic moment with sub-percent precision. We employ the time-momentum representation for the space-like kernel, which is combined with the spatially summed vector correlator computed on CLS ensembles with $N_{\mathrm{f}}=2+1$ flavors of $\mathrm{O}(a)$-improved Wilson fermions, covering six lattice spacings between $0.039$ and $0.097\,$fm and a range of pion masses including the physical value. After accounting for finite-size corrections and isospin-breaking effects, we obtain as our final, continuum-extrapolated result $a_μ^{\mathrm{hvp,\,nlo}}=-101.57(26)_{\mathrm{stat}}(54)_{\mathrm{syst}}\times10^{-11}$. It lies below the estimate provided by the 2025 White Paper of the Muon $(g-2)$ Theory Initiative by $1.4σ$ but is two times more precise. It also exhibits a strong tension of $4.6σ$ with data-driven evaluations based on hadronic cross section measurements excluding the recent result by CMD-3.

hep-lat↗

arXiv2026

Calibrated correlation between heavy-quark masses and Hadronic Vacuum Polarization observables at the precision frontier

The theoretical prediction of the muon anomalous magnetic moment $a_μ$ depends crucially on the Hadronic Vacuum Polarization (HVP), and the tension between its dispersive and lattice-QCD determinations remains unresolved. We show that part of this puzzle can be addressed in the heavy-quark sector, where both descriptions are theoretically clean, by recognizing that the heavy-quark mass and its contribution to $a_μ$ are not independent quantities: both follow from integrals of the same hadronic spectral function, differing only in their integration kernel. Promoting this kernel to a free choice within the relativistic QCD Sum Rules used to determine heavy-quark masses, we break with the conventional notion of a single valid sum rule and instead determine the mass and its HVP contribution simultaneously, from a common, self-consistent framework. This intrinsic construction exploits the anticorrelation between the two quantities to sharpen the final uncertainty, and turns the residual disagreement between the perturbative and hadronic descriptions of the observable into a direct observable-specific diagnostic of residual theory/model dependence, including duality-violation and continuum-modeling effects, unavailable to a determination of the mass alone. We obtain $a_μ^{\rm HVP_{c+b},LO} =(14.46(13)+0.3009(17))\times 10^{-10}$ at leading and $a_μ^{\rm HVP_{c+b}, NLO_{a,b}} = ( -0.5738(95) - 0.01822(13) )\times 10^{-10}$ at next-to-leading order, for charm and bottom contributions, respectively. We compare our next-to-leading-order results with its first available lattice determination, finding good agreement in the charm sector. As a byproduct, we obtain $\hat m_c(\hat m_c)=1267.1(6.8)$ MeV and $\hat m_b(\hat m_b) = 4182.3(7.2)$ MeV, with unprecedented phenomenological precision.

hep-ph↗

arXiv2026

Lattice determination of the higher-order hadronic vacuum polarization contribution to the muon $g-2$

We present the first lattice QCD calculation of the next-to-leading order (NLO) hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment with sub-percent precision. We employ the time-momentum representation combined with the spatially summed vector correlator computed on CLS ensembles with $N_{\mathrm{f}}=2+1$ flavors of $\mathrm{O}(a)$-improved Wilson fermions, spanning six lattice spacings ($0.039$-$0.097\,$fm) and a range of pion masses including the physical value. After accounting for finite-size corrections and isospin-breaking effects, we obtain in the continuum limit $a_μ^{\mathrm{hvp,\,nlo}} = (-101.57 \pm 0.26_{\rm stat} \pm 0.54_{\rm syst}) \times 10^{-11}$, corresponding to a total relative error of 0.6$\%$. Our result lies 1.4$σ$ below the estimate of the 2025 White Paper update and is two times more precise. It also shows a tension of $4.6σ$ with data-driven evaluations based on hadronic cross section measurements prior to the CMD-3 result.

hep-lat↗