Nuclear Theory·nucl-th

Friday·July 19, 2019

9 papers—6 primary·3 cross-listed

07
Reduced uncertainty of the axial $γ Z$ -box correction to the proton's weak charge
Jens Erler🇩🇪 · Mikhail Gorchtein🇩🇪 · Oleksandr Koshchii🇩🇪 · Chien-Yeah Seng🇩🇪 · Hubert Spiesberger🇩🇪
We present the fully up-to-date calculation of the $γ Z$ -box correction which needs to be taken into account to determine the weak mixing angle at low energies from parity-violating electron proton scattering. We make use of neutrino and antineutrino inclusive scattering data to predict the parity-violating structure function $F_{3}^{γ Z}$ by isospin symmetry. Our new analysis confirms previous results for the axial contribution to the $γ Z$ -box graph, and reduces the uncertainty by a factor of~2. In addition, we note that the presence of parity-violating photon-hadron interactions induces an additional contribution via $F_{3}^{γ γ}$ . Using experimental and theoretical constraints on the nucleon anapole moment we are able to estimate the uncertainty associated with this contribution. We point out that future measurements are expected to significantly reduce this latter uncertainty.
↳ hep-phhep-exnucl-exnucl-thPRD(2019)·13 citations
08
What attracts to attractors?
Aleksi Kurkela🇨🇭 · Wilke van der Schee🇨🇭 · Urs Achim Wiedemann🇨🇭 · Bin Wu🇨🇭
Whether, how, and to what extent solutions of Bjorken-expanding systems become insensitive to aspects of their initial conditions is of importance for heavy-ion collisions. Here we study 1+1D and phenomenologically relevant boost-invariant 3+1D systems in which initial conditions approach a universal attractor solution. In Israel-Stewart theory (IS) and kinetic theory where the universal attractor extends to arbitrarily early times, we show that all initial conditions approach the attractor at early times by a power-law while their approach is exponential at late times. In these theories, the physical mechanisms of hydrodynamization operational at late times do not drive the approach to the attractor at early times, and the early-time attractor is reached prior to hydrodynamization. In marked contrast, the attractor in strongly coupled systems is realized concurrent with hydrodynamization. This qualitative difference may offer a basis for discriminating weakly and strongly coupled scenarios of heavy-ion collisions.
↳ hep-phnucl-thPRL(2020)·147 citations
09
Strangeness neutrality and the QCD phase diagram
Fabian Rennecke🇺🇸 · Wei-jie Fu🇨🇳 · Jan M. Pawlowski🇩🇪
Since the incident nuclei in heavy-ion collisions do not carry strangeness, the global net strangeness of the detected hadrons has to vanish. We show that there is an intimate relation between strangeness neutrality and baryon-strangeness correlations. In the context of heavy-ion collisions, the former is a consequence of quark number conservation of the strong interactions while the latter are sensitive probes of the character of QCD matter. We investigate the sensitivity of baryon-strangeness correlations on the freeze-out conditions of heavy-ion collisions by studying their dependence on temperature, baryon- and strangeness chemical potential. The impact of strangeness neutrality on the QCD equation of state at finite chemical potentials will also be discussed. We model the low-energy sector of QCD by an effective Polyakov loop enhanced quark-meson model with 2+1 dynamical quark flavors and use the functional renormalization group to account for the non-perturbative quantum fluctuations of hadrons.
↳ hep-phnucl-thPoS(2019)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE

Reduced uncertainty of the axial γZ-box correction to the proton's weak charge

What attracts to attractors?

Strangeness neutrality and the QCD phase diagram

Affiliations

Reduced uncertainty of the axial $γ Z$ -box correction to the proton's weak charge