Mon·Nov 14, 2022Monday·November 14, 2022

1. 01*

   Multiple breaking patterns in the Brout-Englert-Higgs effect beyond perturbation theory

   Elizabeth Dobson🇦🇹 · Axel Maas🇦🇹 · Bernd Riederer🇦🇹

   In many BSM theories, especially GUTs, introducing a Brout-Englert-Higgs effect allows for multiple breaking patterns of the gauge symmetry. The possibility to select a particular pattern is usually decisive for the phenomenological viability of a theory. Beyond perturbation theory it is necessary to replace the Brout-Englert-Higgs effect by a manifestly gauge-invariant description. We study the simplest case with multiple breaking patterns, an $\text{SU}(3)$ Yang-Mills theory coupled to a single scalar `Higgs' field in the adjoint representation, on the lattice. We find that only one pattern remains at fixed parameters and gauge-fixing strategy, and that the associated quantum effective potential emerges from a non-trivial interplay of many aspects.

   hep-lathep-phhep-thAnnals Phys.(2023)·7 citations
2. 02*

   On the Infinite Variance Problem in Fermion Models

   Andrei Alexandru🇺🇸 · Paulo Bedaque🇺🇸 · Andrea Carosso🇺🇸 · Hyunwoo Oh🇺🇸

   Monte Carlo calculations of fermionic systems with continuous auxiliary fields frequently suffer from a diverging variance. If a system has the infinite variance problem, one cannot estimate observables reliably even with an infinite number of samples. In this paper, we explore a method to deal with this problem based on sampling according to the distribution of a system with an extra time-slice. The necessary reweighting factor is computed both perturbatively and through a secondary Monte Carlo. We show that the Monte Carlo reweigthing coupled to the use of a non-biased estimator of the reweigthing factor leads to a method that eliminates the infinite variance problem at a very small extra cost. We compute the double occupancy in the Hubbard model at half-filling to demonstrate the method and compare the results to well established results obtained by other methods.

   hep-latcond-mat.str-elnucl-thPRD(2023)·7 citations
3. 03*

   Precision tau physics: Challenge for Theory, on and off the lattice

   Amarjit Soni🇺🇸

   $\tau$ is playing an important role in the current B-physics indications from experiments of lepton flavor universality violations(LFUV). This suggests it be given increasing attention theoretically in the coming years, given also the fact that Belle-II will have much larger data samples to study; similar comments also apply to LHCb as well as ATLAS and CMS. The fact that $\tau$ decays provide valuable information on its spin is an added advantage. This gains special significance if the current indications of new physics are upheld since naturalness arguments then strongly suggest that new physics should be accompanied by new CP-odd phase(s). Moreover, the fact that the $\tau$ mass is around 1.8 GeV,~{\it i.e} a lot less than the B-meson mass makes it much easier candidate for lattice studies in great detail and consequently very likely with greater precision. This should help us test the SM and or BSMs with greater precision as needed.

   ↳ hep-phhep-exhep-lat0 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.