Nucleon axial and pseudoscalar form factors from lattice QCD at the physical point

Abstract

We compute the nucleon axial and induced pseudoscalar form factors using three ensembles of gauge configurations, generated with dynamical light quarks with mass tuned to approximately their physical value. One of the ensembles also includes the strange and charm quarks with their mass close to physical. The latter ensemble has large statistics and finer lattice spacing and it is used to obtain final results, while the other two are used for assessing volume effects. The pseudoscalar form factor is also computed using these ensembles. We examine the momentum dependence of these form factors as well as relations based on pion pole dominance and the partially conserved axial-vector current hypothesis.More details on these two fit approaches are given in Sec. VI.

Axion-like Particle Searches at DarkQuest

“…[44] fit D s in the range [−0.6, −0.2] (but they do not provide a best fit value). These values are consistent with three-flavour extractions of g A = 1.283 and g 0 = 0.384 from lattice QCD [47,48] if we take D s ≈ −0.41. The additional ALP term that results from Eq.…”

“…We will use two lucky coincidences. First, in the space-like region the lattice results which provide dipole fits for the isovector [47] and isoscalar [48] couplings find roughly the same "axial mass" (fitting parameter to the dipole form-factor which determines its Q 2 dependence) within uncertainties (m A = 1.169 (72) (27) GeV vs m A = 1.261 ± 0.188 GeV). The second coincidence is that the relevant meson for axial isoscalar coupling with I G (J P C ) = 0 − (0 +− ) is the h 1 with a mass m h 1 = 1.166 GeV and Γ h 1 = 0.375 GeV.…”

First Lattice QCD Study of Proton Twist-3 GPDs

“…As expected, the contribution from 𝐸 + 𝐺 1 has the largest magnitude, followed by 𝐻 + 𝐺 2 . This is in accordance with the findings of the twist-2 case [9], as well as of the usual axial form factors [14]. The values for 𝐺 3 are found to be exactly zero, and 𝐺 4 has a zero real part for 𝑧 ≤ 6𝑎.…”

Isovector Axial Vector Form Factors of the Nucleon from Lattice QCD with $N_{f}=2+1$ $\mathcal O(a)$-improved Wilson Fermions

“…On the right-hand side of fig. 3 we show the comparison of our final result with the experimental values and those obtained by various other lattice collaborations [21][22][23][24][25][26]. Within the 1𝜎 error interval we are in good agreement with the results of other collaborations and with the experimental world average for the electroproduction.…”