Thu·Dec 16, 2021Thursday·December 16, 2021

1. 01*

   Applying machine learning methods to prediction problems of lattice observables

   N. V. Gerasimeniuk🇷🇺 · M. N. Chernodub🇫🇷 · V. A. Goy🇷🇺 · D. L. Boyda🇺🇸 · S. D. Liubimov🇷🇺 · A. V. Molochkov🇷🇺

   We discuss the prediction of critical behavior of lattice observables in SU(2) and SU(3) gauge theories. We show that feed-forward neural network, trained on the lattice configurations of gauge fields as input data, finds correlations with the target observable, which is also true in the critical region where the neural network has not been trained. We have verified that the neural network constructs a gauge-invariant function and this property does not change over the entire range of the parameter space.

   hep-latSciPost Phys.Proc.(2022)·2 citations
2. 02*

   Pseudoscalar transition form factors and the hadronic light-by-light contribution to the muon $g-2$

   Antoine Gérardin🇫🇷 · Jana N. Guenther🇩🇪 · Lukas Varnhorst🇩🇪 · Willem E. A. Verplanke🇫🇷

   We present preliminary results from our calculation of the pseudoscalar transition form factors of the $\eta$ and ${\eta }^{\prime }$ mesons using staggered quarks on $N_f=2+1+1$ gauge ensembles generated by the Budapest-Marseille-Wuppertal collaboration. These transition form factors are an important input for the hadronic light-by-light contribution to the muon $(g-2)$. We first elaborate on the extraction of the masses of the $\eta$ and ${\eta }^{\prime }$ mesons, that mix under the dynamics of QCD. Thereafter, we show our preliminary results for the pseudoscalar transition form factors, focusing on the $\eta$ meson in the absence of mixing.

   hep-lathep-phPoS(2022)·5 citations
3. 03*

   Aspects of finite temperature QCD towards the chiral limit

   Anirban Lahiri🇩🇪

   QCD under extreme conditions has been studied for a long time, and the chiral limit has been a grey area mostly. In this write-up of my talk, I review some of the recent developments made by the community to unveil various features of QCD towards the chiral limit, which includes calculation of the chiral critical temperature and determination of the order of chiral phase transition for various numbers of flavors. Acknowledging the importance of the studies regarding the effective restoration of $U_A(1)$, I try to give a comprehensive overview about the various studies done in the last few years in a comparative manner to realize the current status of the community in this regard. I also discuss very recent efforts about the relevance of various energy-like observables w.r.t. the chiral phase transition.

   hep-lathep-phnucl-exnucl-thPoS(2022)·30 citations
4. 04*

   Isospin-breaking Effects in Octet and Decuplet Baryon Masses

   Alexander M. Segner🇩🇪 · Andrew D. Hanlon🇺🇸 · Renwick J. Hudspith🇩🇪 · Andreas Risch🇩🇪 · Hartmut Wittig🇩🇪

   We present work designed to compute baryon masses on $N_f=2+1$ CLS ensembles including isospin-breaking effects due to non-degenerate light quark masses and electromagnetic interactions. These effects are determined at leading order via a perturbative expansion around the iso-symmetric theory. We furthermore apply a group-theoretical operator construction for the various interpolators describing the different members of the baryon octet and decuplet based on a classification by spin, parity, and flavor content.

   hep-latPoS(2022)·3 citations
5. 05*

   Studying mass generation for gluons

   Gernot Eichmann🇵🇹 · Jan M. Pawlowski🇩🇪

   In covariant gauges, the gluonic mass gap in Yang-Mills theory manifests itself in the basic observation that the massless pole in the perturbative gluon propagator disappears in nonperturbative calculations, but the origin of this behavior is not yet fully understood. We summarize a recent study of the respective dynamics with Dyson-Schwinger equations in Landau-gauge Yang-Mills theory. We identify the parameter that distinguishes the massive Yang-Mills regime from the massless decoupling solutions, whose endpoint is the scaling solution. Similar to the PT-BFM scheme, we find evidence that mass generation in the transverse sector is triggered by longitudinal massless poles.

   ↳ hep-phhep-lathep-thSciPost Phys.Proc.(2022)·1 citation
6. 06*

   New physics behind the new muon $g$-2 puzzle?

   Luca Di Luzio🇮🇹 · Antonio Masiero🇮🇹 · Paride Paradisi🇮🇹 · Massimo Passera🇮🇹

   The recent measurement of the muon $g$-2 at Fermilab confirms the previous Brookhaven result. The leading hadronic vacuum polarization (HVP) contribution to the muon $g$-2 represents a crucial ingredient to establish if the Standard Model prediction differs from the experimental value. A recent lattice QCD result by the BMW collaboration shows a tension with the low-energy $e^{+}{e}^{-}\to \text{hadrons}$ data which are currently used to determine the HVP contribution. We refer to this tension as the new muon $g$-2 puzzle. In this Letter we consider the possibility that new physics contributes to the $e^{+}{e}^{-}\to \text{hadrons}$ cross-section. This scenario could, in principle, solve the new muon $g$-2 puzzle. However, we show that this solution is excluded by a number of experimental constraints.

   ↳ hep-phhep-exhep-latPLB(2022)·34 citations
7. 07*

   Lattice BF Theory, Dumbbells, and Composite Fermions

   Tom Banks🇺🇸 · Bingnan Zhang🇺🇸

   We formulate $U(1)$ $bda$ Chern-Simons theory, which is also called BF theory, on a lattice, adapting a method proposed by Kantor and Susskind for the groups $\mathbb{R}$ and ${\mathbb{Z}}_N$. Our method applies to any finite or infinite abelian group. We study the discrete symmetries and use the model to provide a rigorous treatment of the composite fermion theory of the fractional quantum Hall effect (FQHE), with no ambiguities relating to intersecting Wilson/'t Hooft lines. We derive Jain's fractions, and one can also calculate corrections to the mean field solution within this framework. We also generalize the formalism to higher form gauge models in arbitrary dimension, and suggest a possible non-Abelian extension.

   ↳ hep-thcond-mat.str-elhep-latNPB(2022)·5 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.