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Nuclear Theory·nucl-th

Wednesday·June 19, 2019

7 papers—5 primary·2 cross-listed

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  1. 06

    [Submitted on 17 Jun 2019] (cross-list from hep-ph)

    Jet fragmentation functions for -tagged jets

    Zhong-Bo Kang🇺🇸 · Kyle Lee🇺🇸 · John Terry🇺🇸 · Hongxi Xing🇨🇳

    Recently the LHCb collaboration has measured both longitudinal and transverse momentum distribution of hadrons produced inside -tagged jets in proton-proton collisions at the Large Hadron Collider. These distributions are commonly referred to as jet fragmentation functions and are characterized by the longitudinal momentum fraction of the jet carried by the hadron and the transverse momentum with respect to the jet direction. We derive a QCD formalism within Soft-Collinear Effective Theory to describe these distributions and find that the -dependence provides information on standard collinear fragmentation functions, while -dependence probes transverse momentum dependent (TMD) fragmentation functions. We perform theoretical calculations and compare our results with the LHCb data. We find good agreement for the intermediate region. For -dependence, we suggest binning in both and , which would lead to a more direct probing of TMD fragmentation functions.

    Comments:
    9 pages, 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    1906.07187 [pdf]
    PLB(2019)·36 citations
  2. 07

    [Submitted on 18 Jun 2019] (cross-list from hep-ex)

    Higgs boson production in partonic and electromagnetic interactions with heavy ions

    David d'Enterria🇨🇭

    Higgs boson production in partonic and electromagnetic (photon-photon) interactions of light- and heavy-ions (A-A) at the LHC and future colliders is summarized. Parton-induced cross sections --including gluon-gluon, vector-boson fusion, and associated W, Z, t processes-- are computed at NNLO with MCFM 8.0 using nuclear parton distribution functions. Photon-photon cross sections are computed with MadGraph 5.0 for ultraperipheral A-A interactions with both ions surviving the collision. In the center-of-mass energy range --100 TeV, the ratio of electromagnetic-to-partonic Higgs cross sections is --10. At FCC energies, this ratio is 10--100 times larger in A-A than in p-p thanks to the strong nuclear coherent fluxes. The feasibility of Higgs boson measurements at LHC, HE-LHC, and FCC, in the most-favourable decay channels in partonic and e.m. interactions respectively, is determined taking into account standard acceptance and efficiency losses on the final states, plus selection criteria to minimize the respective continuum backgrounds. Whereas evidence for partonic and e.m. Higgs production requires about 35 and 200 (7 and 30) larger integrated luminosities than those expected for a nominal 1-month run at the LHC (HE-LHC), a observation of both production modes is warranted in just one month at the FCC.

    Comments:
    4 pages, 6 figures. Contribution to the 2019 Moriond-QCD conference
    Subjects:
    High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1906.07536 [pdf]
    1 citation

Affiliations

first authorsco-authorsvia INSPIRE