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Nuclear Theory·nucl-th

Wednesday·December 16, 2020

7 papers—2 primary·5 cross-listed

All7Primary2Cross-lists5
  1. 03

    [Submitted on 14 Dec 2020] (cross-list from hep-ph)

    TMD Fragmentation Functions at NLO

    Markus A. Ebert🇩🇪 · Bernhard Mistlberger🇺🇸 · Gherardo Vita🇺🇸

    We compute the unpolarized quark and gluon transverse-momentum dependent fragmentation functions (TMDFFs) at next-to-next-to-next-to-leading order (NLO) in perturbative QCD. The calculation is based on a relation between the TMDFF and the limit of the semi-inclusive deep inelastic scattering cross section where all final-state radiation becomes collinear to the detected hadron. The required cross section is obtained by analytically continuing our recent computation of the Drell-Yan and Higgs boson production cross section at NLO expanded around the limit of all final-state radiation becoming collinear to one of the initial states. Our results agree with a recent independent calculation by Luo et al.

    Comments:
    20 pages + appendices, 3 figures, 6 ancillary files; v2: journal version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2012.07853 [pdf]
    JHEP(2021)·62 citations
  2. 04

    [Submitted on 14 Dec 2020] (cross-list from hep-ph)

    The Energy-Energy Correlation in the back-to-back limit at NLO and NLL

    Markus A. Ebert🇩🇪 · Bernhard Mistlberger🇺🇸 · Gherardo Vita🇺🇸

    We present the analytic formula for the Energy-Energy Correlation (EEC) in electron-positron annihilation computed in perturbative QCD to next-to-next-to-next-to-leading order (NLO) in the back-to-back limit. In particular, we consider the EEC arising from the annihilation of an electron-positron pair into a virtual photon as well as a Higgs boson and their subsequent inclusive decay into hadrons. Our computation is based on a factorization theorem of the EEC formulated within Soft-Collinear Effective Theory (SCET) for the back-to-back limit. We obtain the last missing ingredient for our computation - the jet function - from a recent calculation of the transverse-momentum dependent fragmentation function (TMDFF) at NLO. We combine the newly obtained NLO jet function with the well known hard and soft function to predict the EEC in the back-to-back limit. The leading transcendental contribution of our analytic formula agrees with previously obtained results in supersymmetric Yang-Mills theory. We obtain the Mellin moment of the bulk region of the EEC using momentum sum rules. Finally, we obtain the first resummation of the EEC in the back-to-back limit at NLL accuracy, resulting in a factor of reduction of uncertainties in the peak region compared to NLL predictions.

    Comments:
    32 pages, many wonderful figures, 3 appendices, 7 ancillary files. v2: Journal version. Added regulator independent jet functions, comparisons with OPAL data and O(as^3) numerical fixed order results
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2012.07859 [pdf]
    JHEP(2021)·81 citations
  3. 05

    [Submitted on 15 Dec 2020] (cross-list from hep-ph)

    Hadronic Atom as a Key to Revealing the Mystery

    Zhen-Hua Zhang🇨🇳 · Feng-Kun Guo🇨🇳

    The , whose mass coincides with the threshold, is the most extended hadron object. Since its discovery in 2003, debates have never stopped regarding its internal structure. We propose a new object, the atom, which is the composite system with positive charge parity and a mass of MeV, formed mainly due to the Coulomb force. We show that a null signal of the atom can be used to put a lower limit on the binding energy of the . From the current knowledge of the properties, the production rate for the atom relative to the in decays and at hadron colliders should be at least . New insights into the will be obtained through studying the atom.

    Comments:
    6 pages, 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2012.08281 [pdf]
    PRL(2021)·19 citations
  4. 06

    [Submitted on 15 Dec 2020] (cross-list from hep-th)

    All order effective action for charge diffusion from Schwinger-Keldysh holography

    Yanyan Bu🇨🇳 · Tuna Demircik🇰🇷 · Michael Lublinsky🇮🇱

    An effective action for diffusion of a conserved charge is derived to all orders in the derivative expansion within a holographic model dual to the Schwinger-Keldysh closed time path. A systematic approach to solution of the 5D Maxwell equations in a doubled Schwarzschild-AdS black brane geometry is developed. Constitutive relation for the stochastic charge current is shown to have a term induced by thermal fluctuations (coloured noise). All transport coefficient functions parameterising the effective action and constitutive relations are computed analytically in the hydrodynamic expansion, and then numerically for finite momenta.

    Comments:
    v1: 59 pages, 11 multi-figures; v2: 53 pages in JHEP style, refs added, one appendix added, revised the partially off-shell procedure based on bulk path integral
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2012.08362 [pdf]
    JHEP(2021)·29 citations
  5. 07

    [Submitted on 15 Dec 2020] (cross-list from hep-ph)

    Hadronization of correlated gluon fields

    Moritz Greif🇩🇪 · Carsten Greiner🇩🇪 · Simon Plätzer🇦🇹 · Björn Schenke🇺🇸 · Sören Schlichting🇩🇪

    Following an explicit example, we present the chain of steps required for an event-by-event description of hadron production in high energy hadronic and nuclear collisions. We start from incoming nuclei, described in the Color Glass Condensate effective theory, whose collision creates the gluon fields of the glasma. Individual gluons are then sampled from the gluon fields' Husimi (smeared Wigner) distributions, and clustered using a new spacetime based algorithm. Clusters are fed into the Herwig event generator, which performs the hadronization, conserving energy and momentum. We discuss the physical implications of smearing and problems with the quasi particle picture for the studied processes. We compute spectra of charged hadrons and identified particles and their azimuthal momentum anisotropies, and address systematic uncertainties on observables, resulting from the general lack of detailed knowledge of the hadronization mechanism.

    Comments:
    12 pages, 15 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2012.08493 [pdf]
    PRD(2021)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE