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Nuclear Theory·nucl-th

Tuesday·May 17, 2022

8 papers—6 primary·2 cross-listed

All8Primary6Cross-lists2
  1. 07

    [Submitted on 13 May 2022] (cross-list from hep-ph)

    Power Counting Energy Flow Polynomials

    Pedro Cal🇩🇪 · Jesse Thaler🇺🇸 · Wouter J. Waalewijn🇳🇱

    Power counting is a systematic strategy for organizing collider observables and their associated theoretical calculations. In this paper, we use power counting to characterize a class of jet substructure observables called energy flow polynomials (EFPs). EFPs provide an overcomplete linear basis for infrared-and-collinear safe jet observables, but it is known that in practice, a small subset of EFPs is often sufficient for specific jet analysis tasks. By applying power counting arguments, we obtain linear relationships between EFPs that hold for quark and gluon jets to a specific order in the power counting. We test these relations in the parton shower generator Pythia, finding excellent agreement. Power counting allows us to truncate the basis of EFPs without affecting performance, which we corroborate through a study of quark-gluon tagging and regression.

    Comments:
    36 pages, 8 tables, 11 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2205.06818 [pdf]
    JHEP(2022)·12 citations
  2. 08

    [Submitted on 16 May 2022] (cross-list from hep-ph)

    Exclusive production of a pair of high transverse momentum photons in pion-nucleon collisions for extracting generalized parton distributions

    Jian-Wei Qiu🇺🇸 · Zhite Yu🇺🇸

    We show that exclusive production of a pair of high transverse momentum photons in pion-nucleon collisions can be systematically studied in QCD factorization approach if the photon's transverse momentum with respect to the colliding pion is much greater than . We demonstrate that the leading power non-perturbative contributions to the scattering amplitudes of this exclusive process are process-independent and can be systematically factorized into universal pion's distribution amplitudes (DAs) and nucleon's generalized parton distributions (GPDs), which are convoluted with corresponding infrared safe and perturbatively calculable short-distance hard parts. The correction to this factorized expression is suppressed by powers of . We demonstrate quantitatively that this new type of exclusive processes is not only complementary to existing processes for extracting GPDs, but also capable of providing an enhanced sensitivity to the dependence of both DAs and GPDs on the active parton's momentum fraction . We also introduce additional, but the same type of exclusive observables to enhance our capability to explore GPDs, in particular, their -dependence.

    Comments:
    60 pages, 28 figures; extended reference and some discussions, with the main results unchanged
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    2205.07846 [pdf]
    JHEP(2022)·68 citations

Affiliations

first authorsco-authorsvia INSPIRE