Wed·Nov 9, 2022Wednesday·November 9, 2022

1. 01*

   Spectroscopy of chimera baryons in a $Sp(4)$ lattice gauge theory

   Ho Hsiao🇹🇼 · Ed Bennett🇬🇧 · Deog Ki Hong🇰🇷 · Jong-Wan Lee🇰🇷 · C.-J. David Lin🇹🇼 · Biagio Lucini🇬🇧 · Maurizio Piai🇬🇧 · Davide Vadacchino🇬🇧

   Chimera baryons are an important element of strongly coupled theories that provide a microscopic origin for UV complete composite Higgs models (CHMs), since they play the role of top partners in top partial compositeness. In a particular interesting realisation of CHMs based upon an underlying $Sp(4)$ gauge theory, such exotic objects are composed of two fermion constituents transforming on the fundamental, and one on the 2-index antisymmetric representations. We perform lattice computations of the chimera baryon spectrum in the quenched approximation. We present preliminary results for the masses of various chimera baryons with different quantum numbers, including the one interpreted as the top partner. We test the technology needed for future calculations with dynamical fermions.

   hep-lathep-ph16 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 report on our progress toward the computation of the ${\pi }^0$, $\eta$ and ${\eta }^{\prime }$ transition form factors using staggered quarks on $N_f=2+1+1$ gauge ensembles generated by the Budapest-Marseille-Wuppertal collaboration. These form factors are essential ingredients to evaluate the pseudoscalar-pole contributions to the hadronic light-by-light scattering in the muon $g-2$. Preliminary results for the pseudoscalar-pole contributions are presented, at finite lattice spacing, for all three light mesons.

   hep-lathep-exhep-phPoS(2023)·5 citations
3. 03*

   Non-singlet quark helicity PDFs of the nucleon from pseudo-distributions

   Robert G. Edwards🇺🇸 · Colin Egerer🇺🇸 · Joseph Karpie🇺🇸 · Nikhil Karthik🇺🇸 · Christopher J. Monahan🇺🇸 · Wayne Morris🇺🇸 · Kostas Orginos🇺🇸 · Anatoly Radyushkin🇺🇸 · David Richards🇺🇸 · Eloy Romero🇺🇸 · Raza Sabbir Sufian🇺🇸 · Savvas Zafeiropoulos🇫🇷

   The non-singlet helicity quark parton distribution functions (PDFs) of the nucleon are determined from lattice QCD, by jointly leveraging pseudo-distributions and the distillation spatial smearing paradigm. A Lorentz decomposition of appropriately isolated space-like matrix elements reveals pseudo-distributions that contain information on the leading-twist helicity PDFs, as well as an invariant amplitude that induces an additional $z^2$ contamination of the leading-twist signal. An analysis of the short-distance behavior of the space-like matrix elements using matching coefficients computed to next-to-leading order (NLO) exposes the desired PDF up to this additional $z^2$ contamination. Due to the non-conservation of the axial current, we elect to isolate the helicity PDFs normalized by the nucleon axial charge at the same scale ${\mu }^2$. The leading-twist helicity PDFs as well as several sources of systematic error, including higher-twist effects, discretization errors, and the aforementioned $z^2$ contaminating amplitude are jointly determined by characterizing the computed pseudo-distribution in a basis of Jacobi polynomials. The Akaike Information Criterion is exploited to effectively average over distinct model parameterizations and cuts on the pseudo-distribution. Encouraging agreement is observed with recent global analyses of each non-singlet quark helicity PDF, notably a rather small non-singlet anti-quark helicity PDF for all quark momentum fractions.

   hep-lathep-phJHEP(2023)·24 citations
4. 04*

   Light double-gluon hybrid states from QCD sum rules

   Niu Su🇨🇳 · Hua-Xing Chen🇨🇳 · Wei Chen🇨🇳 · Shi-Lin Zhu🇨🇳

   We study the double-gluon hybrid states with the quark-gluon contents $\bar{q}qgg$ ($q=u/d$) and $\bar{s}sgg$. We construct twelve double-gluon hybrid currents with various quantum numbers, five of which are found to be zero due to some internal symmetries between the two gluon fields. We use the rest seven currents to perform QCD sum rule analyses. Especially, the masses of the double-gluon hybrid states with the exotic quantum number $J^{PC}=2^{+-}$ are calculated to be $M_{|\bar{q}qgg;2^{+-}⟩}=2.26_{-0.25}^{+0.20}$ GeV and $M_{|\bar{s}sgg;2^{+-}⟩}=2.38_{-0.25}^{+0.19}$ GeV. Their two- and three-meson decay patterns are also investigated.

   ↳ hep-phhep-exhep-latPRD(2023)·11 citations
5. 05*

   Stability of homogeneous chiral phases against inhomogeneous perturbations in 2+1 dimensions

   Marc Winstel🇩🇪 · Laurin Pannullo🇩🇪

   In this work, inhomogeneous chiral phases are studied in a variety of Four-Fermion and Yukawa models in $2+1$ dimensions at zero and non-zero temperature and chemical potentials. Employing the mean-field approximation, we do not find indications for an inhomogeneous phase in any of the studied models. We show that the homogeneous phases are stable against inhomogeneous perturbations. At zero temperature, full analytic results are presented.

   ↳ hep-phcond-mat.str-elhep-latPoS(2023)·16 citations
6. 06*

   Factorization for quasi-TMD distributions of sub-leading power

   Simone Rodini🇫🇷 · Alexey Vladimirov🇪🇸

   The quasi-transverse-momentum dependent (qTMD) distributions are equal-time correlators that can be computed within the lattice QCD approach. In the regime of large hadron's momentum, qTMD distributions are expressed in terms of standard TMD distributions via the factorization theorem. We derive the corresponding factorization theorem at the next-leading power (NLP), and, for the first time, we present the factorized expressions for a large class of qTMD distributions of sub-leading power. The NLP expression contains TMD distributions of twist-two, twist-three, and a new lattice-specific nonperturbative function. We point out that some of the qTMD distributions considered in this work can be employed to extract the Collins-Soper kernel using the standard techniques of different-momenta-ratio. We provide NLO expressions for all the elements of the factorization theorem. Also, for the first time, we explicitly demonstrate the restoration of boost invariance in NLP TMD factorization.

   ↳ hep-phhep-lathep-thJHEP(2023)·31 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.