Thu·Nov 18, 2021Thursday·November 18, 2021

1. 01*

   Hadronic Parity Violation from 4-quark Interactions

   Aniket Sen🇩🇪 · Marcus Petschlies🇩🇪 · Nikolas Schlage🇩🇪 · Carsten Urbach🇩🇪

   We present an exploratory investigation of the parity odd $\Delta I=1$ pion-nucleon coupling $h_{\pi }^1$ from lattice QCD. Based on the PCAC relation, we study the parity-conserving effective Hamiltonian and extract the coupling by determining the nucleon mass splitting arising from the effective 4-quark interactions using the Feynman-Hellmann theorem. We present preliminary results of the mass shift for a $32^3\times 64$ ensemble of $N_f=2+1+1$ twisted mass fermions at pion mass $260$ MeV and lattice spacing $a=0.097$ fm.

   hep-latPoS(2022)·9 citations
2. 02*

   Infrared physics of the $\mathrm{SU}(2)$ Georgi-Glashow crossover transition

   Lauri Niemi🇫🇮 · Kari Rummukainen🇫🇮 · Riikka Seppä🇫🇮 · David Weir🇫🇮

   We perform a lattice study of the phase transition in the $\mathrm{SU}(2)$ Georgi-Glashow model in three dimensions, where the gauge symmetry is broken to $\mathrm{U}(1)$ by the Higgs mechanism and a photon-like state appears. Due to condensation of monopoles the photon acquires a mass, which depends on the number density of the monopoles. We show that the monopole density can be renormalised on the lattice using gradient flow. Our preliminary results suggest that Polyakov's semiclassical relation between the photon mass and the renormalised monopole density is valid also at the nonperturbative level.

   hep-latPoS(2022)·1 citation
3. 03*

   Proton momentum and angular momentum decompositions with overlap fermions

   Gen Wang🇺🇸 · Yi-Bo Yang🇨🇳 · Jian Liang🇨🇳 · Terrence Draper🇺🇸 · Keh-Fei Liu (chiQCD Collaboration)🇺🇸

   We present a calculation of the proton momentum and angular momentum decompositions using overlap fermions on a $2+1$-flavor RBC/UKQCD domain-wall lattice at 0.143 fm with a pion mass of 171 MeV which is close to the physical one. A complete determination of the momentum and angular momentum fractions carried by up, down, strange and glue inside the proton has been done with valence pion masses varying from 171 to 391 MeV. We have utilized fast Fourier transform on the stochastic-sandwich method for connected-insertion parts and the cluster-decomposition error reduction technique for disconnected-insertion parts has been used to reduce statistical errors. The full nonperturbative renormalization and mixing between the quark and glue operators are carried out. The final results are normalized with the momentum and angular momentum sum rules and reported at the physical valence pion mass at $\overline{\mathrm{MS}}(\mu =2\mathrm{GeV})$. The renormalized momentum fractions for the quarks and glue are $⟨x{⟩}^q=0.491(20)(23)$ and $⟨x{⟩}^g=0.509(20)(23)$, respectively, and the renormalized total angular momentum fractions for quarks and glue are $2J^q=0.539(22)(44)$ and $2J^g=0.461(22)(44)$, respectively. The quark spin fraction is $\Sigma =0.405(25)(37)$ from our previous work and the quark orbital angular momentum fraction is deduced from $2L^q=2J^q-\Sigma$ to be $0.134(22)(44)$.

   hep-lathep-phPRD(2022)·43 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.