Nuclear Theory·nucl-th

Monday·October 24, 2016

4 papers—1 primary·3 cross-listed

01
Partonic structure of neutral pseudoscalars via two photon transition form factors
Khepani Raya🇲🇽 · Minghui Ding🇨🇳 · Adnan Bashir🇲🇽 · Lei Chang🇨🇳 · Craig D. Roberts🇺🇸
The $γ γ^{*} \to η_{c, b}$ transition form factors are computed using a continuum approach to the two valence-body bound-state problem in relativistic quantum field theory, and thereby unified with equivalent calculations of electromagnetic pion elastic and transition form factors. The resulting $γ γ^{*} \to η_{c}$ form factor, $G_{η_{c}} (Q^{2})$ , is consistent with available data: significantly, at accessible momentum transfers, $Q^{2} G_{η_{c}} (Q^{2})$ lies well below its conformal limit. These observations confirm that the leading-twist parton distribution amplitudes (PDAs) of heavy-heavy bound-states are compressed relative to the conformal limit. A clear understanding of the distribution of valence-quarks within mesons thus emerges; a picture which connects Goldstone modes, built from the lightest-quarks in Nature, with systems containing the heaviest valence-quarks that can now be studied experimentally, and highlights basic facts about manifestations of mass within the Standard Model.
nucl-thhep-exhep-lathep-ph+1PRD(2017)·68 citations
02
Production of exotic charmonium in $γ γ$ interactions at hadronic colliders
B. D. Moreira🇧🇷 · C. A. Bertulani🇺🇸 · V. P. Goncalves🇧🇷 · F. S. Navarra🇧🇷
In this paper we investigate the Exotic Charmonium (EC) production in $γ γ$ interactions present in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC) energies as well as for the proposed energies of the Future Circular Collider (FCC). Our results demonstrate that the experimental study of these processes is feasible and can be used to constrain the theoretical decay widths and shed some light on the configuration of the considered multiquark states.
↳ hep-phhep-exnucl-exnucl-thPRD(2016)·31 citations
03
Electrical Conductivity of Quark-Gluon Plasma in Strong Magnetic Fields
Koichi Hattori🇨🇳 · Daisuke Satow🇩🇪
We compute the electrical conductivity of quark-gluon plasma in a strong magnetic field $B$ with quantum field theory at finite temperature using the lowest Landau level approximation. We provide the one-loop result arising from 1-to-2 scattering processes whose kinematics are satisfied by the (1+1) dimensional fermion dispersion relation. Due to the chirality conservation, the conductivity diverges in the massless limit, and is sensitive to the value of the current quark mass. As a result, we find that the conductivity along the direction of the magnetic field is quite large compared with the value at $B = 0$ , mainly because of the small value of the current quark mass. We show that the resummation of the ladder diagrams for the current-current correlator gives rise to only sub-leading contributions beyond the leading-log order, and thus verify our one-loop result at the leading-log accuracy. We also discuss possible implications for the relativistic heavy-ion collisions.
↳ hep-phnucl-thPRD(2016)·113 citations
04
Longitudinal Conductivity in Strong Magnetic Field in Perturbative QCD: Complete Leading Order
Koichi Hattori🇨🇳 · Shiyong Li🇺🇸 · Daisuke Satow🇩🇪 · Ho-Ung Yee🇺🇸
We compute the longitudinal electrical conductivity in the presence of strong background magnetic field in complete leading order of perturbative QCD, based on the assumed hierarchy of scales $α_{s} e B ≪ (m_{q}^{2}, T^{2}) ≪ e B$ . We formulate an effective kinetic theory of lowest Landau level quarks with the leading order QCD collision term arising from 1-to-2 processes that become possible due to 1+1 dimensional Landau level kinematics. In small $m_{q} / T ≪ 1$ regime, the longitudinal conductivity behaves as $σ_{z z} \sim e^{2} (e B) T / (α_{s} m_{q}^{2} lo g (m_{q} / T))$ , where the quark mass dependence can be understood from the chiral anomaly with the axial charge relaxation provided by a finite quark mass $m_{q}$ . We also present parametric estimates for the longitudinal and transverse "color conductivities" in the presence of strong magnetic field, by computing dominant damping rates for quarks and gluons that are responsible for color charge transportation. We observe that the longitudinal color conductivity is enhanced by strong magnetic field, which implies that the sphaleron transition rate in perturbative QCD is suppressed by strong magnetic field due to the enhanced Lenz's law in color field dynamics.
↳ hep-phhep-thnucl-thPRD(2017)·108 citations

Affiliations

first authorsco-authorsvia INSPIRE

Partonic structure of neutral pseudoscalars via two photon transition form factors

Production of exotic charmonium in γγ interactions at hadronic colliders

Electrical Conductivity of Quark-Gluon Plasma in Strong Magnetic Fields

Longitudinal Conductivity in Strong Magnetic Field in Perturbative QCD: Complete Leading Order

Affiliations

Production of exotic charmonium in $γ γ$ interactions at hadronic colliders