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Nuclear Theory·nucl-th

Monday·June 8, 2020

8 papers—1 primary·7 cross-listed

All8Primary1Cross-lists7
  1. 02

    [Submitted on 4 Jun 2020] (cross-list from hep-ph)

    Relativistic corrections to the vector meson light front wave function

    Tuomas Lappi🇫🇮 · Heikki Mäntysaari🇫🇮 · Jani Penttala🇫🇮

    We compute a light front wave function for heavy vector mesons based on long distance matrix elements constrained by decay width analyses in the Non Relativistic QCD framework. Our approach provides a systematic expansion of the wave function in quark velocity. The first relativistic correction included in our calculation is found to be significant, and crucial for a good description of the HERA exclusive production data. When looking at cross section ratios between nuclear and proton targets, the wave function dependence does not cancel out exactly. In particular the fully non-relativistic limit is found not to be a reliable approximation even in this ratio. The important role of the Melosh rotation to express the rest frame wave function on the light front is illustrated.

    Comments:
    22 pages, 7 figures; v2: matches published version; v3: corrected typos in Eqs. 58 and 59
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2006.02830 [pdf]
    PRD(2020)·71 citations
  2. 03

    [Submitted on 4 Jun 2020] (cross-list from hep-ph)

    Deuteron and Antideuteron Coalescence in Heavy-Ion Collisions: Energy Dependence of the Formation Geometry

    Apiwit Kittiratpattana🇹🇭 · Michael Florian Wondrak🇩🇪 · Medina Hamzic🇧🇦 · Marcus Bleicher🇩🇪 · Christoph Herold🇹🇭 · Ayut Limphirat🇹🇭

    We investigate the collision energy dependence of deuteron and antideuteron emission in the RHIC-BES low- to mid-energy range GeV where the formation rate of antinuclei compared to nuclei is strongly suppressed. In the coalescence picture, this can be understood as bulk emission for nuclei in contrast to surface emission for antinuclei. By comparison with experimental data on the coalescence parameter , we are able to extract the respective source geometries. This interpretation is further supported by results from the UrQMD transport model, and establishes the following picture: At low energies, nucleons freeze out over the total fireball volume, while antinucleons are annihilated inside the nucleon-rich fireball and can only freeze out on its surface. Towards higher energies, this annihilation effect becomes irrelevant (due to the decreasing baryochemical potential) and the system's freeze-out is driven by the mesons. Thus, the nucleon and antinucleon freeze-out distributions become similar with increasing energy.

    Comments:
    6 pages, 6 figures, submitted to European Physical Journal A
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2006.03052 [pdf]
    EPJA(2020)·15 citations
  3. 04

    [Submitted on 4 Jun 2020] (cross-list from hep-ph)

    Collinear expansion for color singlet cross sections

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

    We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO.

    Comments:
    39 pages, 1 awesome figure; v2: journal version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2006.03055 [pdf]
    JHEP(2020)·27 citations
  4. 05

    [Submitted on 4 Jun 2020] (cross-list from hep-ph)

    N-jettiness beam functions at N3LO

    Markus Ebert🇺🇸 · Bernhard Mistlberger🇺🇸 · Gherardo Vita🇺🇸

    We present the first complete calculation for the quark and gluon -jettiness () beam functions at next-to-next-to-next-to-leading order (NLO) in perturbative QCD. Our calculation is based on an expansion of the differential Higgs boson and Drell-Yan production cross sections about their collinear limit. This method allows us to employ cutting edge techniques for the computation of cross sections to extract the universal building blocks in question. The class of functions appearing in the matching coefficents for all channels includes iterated integrals with non-rational kernels, thus going beyond the one of harmonic polylogarithms. Our results are a key step in extending the subtraction methods to NLO, and to resum distributions at NLL accuracy both for quark as well as for gluon initiated processes.

    Comments:
    7 wonderful figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2006.03056 [pdf]
    JHEP(2020)·60 citations
  5. 06

    [Submitted on 4 Jun 2020] (cross-list from nucl-ex)

    Upgrade of IAEA recommended data of selected nuclear reactions for production of PET and SPECT isotopes

    A. Hermanne · F. T. Tárkányi · A. V. Ignatyuk · S. Takács · R. Capote

    An IAEA research project was dedicated to the compilation, evaluation and recommendation of cross-section data for the accelerator production of C, N, O, F, Cu, and I positron-emitting radionuclides clinically used for PET imaging, and for the accelerator production of two gamma emitters, Rb and I, used in SPECT imaging. Cross sections for 19 charged-particle induced reactions that can be employed for radionuclide accelerator production were evaluated including uncertainties. The resulting reference cross-section data were obtained from Padé fits to selected and corrected experimental data, and integral thick target yields were subsequently deduced. Uncertainties in the fitted results were estimated via a Padé least-squares method with the addition of a 4\% assessed systematic uncertainty to the estimated experimental uncertainty. Experimental data were also compared with theoretical predictions available from the TENDL library. All of the numerical reference cross-section data with their corresponding uncertainties and deduced integral thick target yields are available on-line at the IAEA-NDS medical portal https://www-nds.iaea.org/medportal/ and also at the IAEA-NDS web page https://www-nds.iaea.org/medical/.

    Comments:
    24 pages, 36 figures, 150 references
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2006.03125 [pdf]
    Nucl.Data Sheets(2021)·7 citations
  6. 07

    [Submitted on 4 Jun 2020] (cross-list from gr-qc)

    Neutron star tidal deformability and equation of state constraints

    Katerina Chatziioannou🇺🇸

    Despite their long history and astrophysical importance, some of the key properties of neutron stars are still uncertain. The extreme conditions encountered in their interiors, involving matter of uncertain composition at extreme density and isospin asymmetry, uniquely determine the stars' macroscopic properties within General Relativity. Astrophysical constraints on those macroscopic properties, such as neutron star masses and radii, have long been used to understand the microscopic properties of the matter that forms them. In this article we discuss another astrophysically observable macroscopic property of neutron stars that can be used to study their interiors: their tidal deformation. Neutron stars, much like any other extended object with structure, are tidally deformed when under the influence of an external tidal field. In the context of coalescences of neutron stars observed through their gravitational wave emission, this deformation, quantified through a parameter termed the \emph{tidal deformability}, can be measured. We discuss the role of the tidal deformability in observations of coalescing neutron stars with gravitational waves and how it can be used to probe the internal structure of Nature's most compact matter objects. Perhaps inevitably, a large portion of the discussion will be dictated by GW170817, the most informative confirmed detection of a binary neutron star coalescence with gravitational waves as of the time of writing.

    Comments:
    invited review for General Relativity and Gravitation, published version
    Subjects:
    General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2006.03168 [pdf]
    Gen.Rel.Grav.(2020)·358 citations
  7. 08

    [Submitted on 5 Jun 2020] (cross-list from hep-th)

    Zilch Vortical Effect, Berry Phase, and Kinetic Theory

    Xu-Guang Huang🇨🇳 · Pavel Mitkin🇷🇺 · Andrey V. Sadofyev🇷🇺 · Enrico Speranza🇩🇪

    Rotating photon gas exhibits a chirality separation along the angular velocity which is manifested through a generation of helicity and zilch currents. In this paper we study this system using the corresponding Wigner function and construct elements of the covariant chiral kinetic theory for photons from first principles. The Wigner function is solved order-by-order in and the unconstrained terms are fixed by matching with quantum field theory results. We further consider the zilch and helicity currents and show that both manifestations of the chirality transport originate in the Berry phase of photons similarly to other chiral effects. Constructing the kinetic description from the Wigner function we find that the frame vector needed to fix the definition of spin of a massless particle is, in fact, the vector of the residual gauge freedom for the free Maxwell theory. We also briefly comment on the possible relation between vortical responses in rotating systems of massless particles and the anomalies of underlying quantum field theory.

    Comments:
    19 pages, no figures
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2006.03591 [pdf]
    JHEP(2020)·60 citations

Affiliations

first authorsco-authorsvia INSPIRE