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1. Progress in top-quark pair production cross section calculations and impact on parton distribution functions of the proton

   https://doi.org/10.22323/1.478.0332  

   Guzzi, Marco; Ablat, Alim; Dulat, Sayipjamal; Hou, T-J; Kidonakis, Nikolaos; Sitiwaldi, Ibrahim; Tonero, Alberto; Xie, Keping; Yuan, C-P (January 2025, Sissa Medialab)

   We discuss the impact of eligible top-quark pair production differential cross-section measurements at the LHC with a collision energy of 13 TeV on the parton distribution functions (PDFs) of the proton as well as the impact of approximate next-to-next-to-next-to-leading order (aN3LO) QCD corrections combined with next-to-leading order (NLO) electroweak (EW) corrections on tt¯ observables. We illustrate the effects on the gluon PDF at large x from an optimal baseline selection of data in NNLO global fits, and show comparisons between the theory prediction for tt¯ total and differential cross sections at aN3LO QCD combined with NLO EW and recent measurements from the ATLAS and CMS collaborations at the LHC. 

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2. Parton Distribution Functions and Lattice QCD

   https://doi.org/10.1051/epjconf/201920601003  

   Lin, Huey-Wen; Yang, A.; Wang, W.Y.; Ng, S.C.C.; Chan, A.H.; Oh, C.H.; Phua, K.K. (January 2019, EPJ Web of Conferences)

   Recently, there have been rapid developments in lattice-QCD calculations of proton structure, especially in the parton distribution functions (PDFs). We overcame a longstanding obstacle and for the first time in lattice-QCD are able to directly calculate the Bjorken- x dependence of the quark, helicity and transversity distributions. The PDFs are obtained using the large-momentum effective field theory (LaMET) framework where the full Bjorken- x dependence of finite-momentum PDFs, called “quasi-PDFs”, can be calculated on the lattice. The quasi-PDF nucleon matrix elements are renormalized non-perturbatively in RI/MOM-scheme. Following a nonperturbative renormalization of the parton quasi-distribution in a regularization-independent momentum-subtraction scheme, we establish its matching to the $$ \overline {{\rm{MS}}} $$ PDF and calculate the non-singlet matching coefficient at next-to-leading order in perturbation theory. In this proceeding, I will show the progress that has been made in recent years, highlighting the latest state-of-the art PDF calculations at the physical pion mass. Future impacts on the large- x global PDF fits are also discussed. 

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3. 2019/20 lessons from τ(Ωc0) and τ(Ξc0) and CP asymmetry in charm decays

   https://doi.org/10.1142/S0217751X20300136  

   Bianco, S.; Bigi, I. I. (August 2020, International Journal of Modern Physics A)

   null (Ed.)

   Our 2003 “Cicerone” had discussed charm dynamics with different directions and levels. 1 Here we focus on two items, where the “landscape” has changed sizably. (a) The lifetimes and semileptonic decays of charm hadrons show the impact of nonperturbative QCD and to which degree one can apply heavy quark expansion (HQE) for charm hadrons. It is more complex as we have learnt from 2019/20 data. (b) CP asymmetry has been established in 2019: 2 [Formula: see text] is quite an achievement by the LHCb collaboration! Our community is at the beginning of a long travel for fundamental dynamics. Can the SM account for these? We discuss the assumptions that were made up to 2018 data and new conclusions from 2019/20 ones. We need more data; however, one has to discuss correlations between different transitions. We give an Appendix, what we have learnt for large CP asymmetry in [Formula: see text]. 

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4. Quarkonia in Medium and Transport in Heavy-Ion Collisions

   https://doi.org/10.22323/1.465.0114  

   Rapp, Ralf (February 2025, Sissa Medialab)

   The transport and spectral properties of heavy quarkonia in hot QCD matter are a central ingredient to describe their observables in high-energy heavy-ion collisions. We review recent activity in evaluating these properties, including a nonperturbative quantum many-body approach where the basic two-body interaction kernel is constrained by quantities that can be computed with good precision in thermal lattice QCD. We then give a brief overview of quarkonium transport approaches to heavy-ion collisions. Focusing on the semiclassical approach we discuss the current interpretation of charmonium and bottomonium observables at RHIC and the LHC, including excitation functions that started with 𝐽/𝜓 and 𝜓′ data from the heavy-ion program at the SPS. 

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5. The PDFLattice2017 workshop: a summary report

   https://doi.org/10.22323/1.297.0211  

   Nocera, Emanuele Roberto; Lin, Huey-Wen; Olness, Fred; Orginos, Kostas; Rojo, Juan (December 2017, XXV International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2017))

   The workshop on Parton Distributions and Lattice Calculations in the LHC era (PDFLattice2017) was hosted at Balliol College, Oxford (UK), from 22nd to 24th March 2017. The workshop brought together the lattice-QCD and the global-fit physicists who devote their efforts to determine the parton distribution functions (PDFs) of the proton. The goals were to make the two communities more familiar between each other, review developments from both sides, and set precision targets for lattice calculations so that they can contribute, together with the forthcoming experimental input, to the next generation of PDF determinations. This contribution summarises the relevant outcome of the workshop, in anticipation of a thorough white paper. 

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