Nuclear Theory·nucl-th

Tuesday·November 29, 2016

15 papers—12 primary·3 cross-listed

13
Nucleon spin and quark content at the physical point
C. Alexandrou (Univ. of Cyprus and The Cyprus Inst.)🇨🇾 · M. Constantinou🇨🇾 · K. Hadjiyiannakou🇨🇾 · Ch. Kallidonis🇨🇾 · G. Koutsou (The Cyprus Inst.)🇨🇾 · K. Jansen🇩🇪 · Ch. Wiese (DESY-Zeuthen)🇩🇪 · A. Vaquero Avilés-Casco (INFN-Milan)🇮🇹
We present results on the spin and quark content of the nucleon using $N_{f} = 2$ twisted mass clover-improved fermion simulations with a pion mass close to its physical value. We use recently developed methods to obtain accurate results for both connected and disconnected contributions. We provide results for the axial charge, quark and gluon momentum fraction as well as the light, strange and charm $σ$ -terms.
↳ hep-lathep-phnucl-thPoS(2016)·12 citations
14
Phenomenological analysis of associated production of $Z^{0} + b$ in the $b \to J / ψ X$ decay channel at the LHC
Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇨🇭
The ATLAS collaboration recently reported on the first observation of associated-production of a $Z^{0}$ boson with a $J / ψ$ . We recently claimed that the corresponding yield of the {\it prompt} $J / ψ$ was dominated by double parton scatterings in the ATLAS acceptance with a somewhat small value of $σ_{eff}$ . We also found out that single parton scatterings were only dominant at large transverse momenta. We present here the first phenomenological analysis of another part of the ATLAS data sample, namely of a $Z^{0}$ boson plus a {\it non-prompt} $J / ψ$ . Our study is performed at next-to-leading order in $α_{s}$ and includes parton-shower effects via the {\sc\small MadGraph5_aMC@NLO} framework. We find out that the data, unlike the case of prompt $J / ψ + Z^{0}$ , do not hint at significant DPS contributions. Owing to the current experimental and theoretical uncertainties, there is still a room for these but with a lower limit of $σ_{eff}$ close to 5 mb. We stress the importance of QCD corrections to account for the ATLAS data.
↳ hep-phhep-exnucl-exnucl-thNPB(2017)·30 citations
15
The effect of ionic correlations on radiative properties in the solar interior and terrestrial experiments
Menahem Krief (HUJI) · Yair Kurzweil (NRCN) · Alexander Feigel (HUJI) · Doron Gazit (HUJI)
Intending to solve the decade old problem of solar opacity, we report substantial photoabsorption uncertainty due to the effect of ion-ion correlations. By performing detailed opacity calculations of the solar mixture, we find that taking into account the ionic structure changes the Rosseland opacity near the convection zone by about 10%. We also report about 15% difference in the Rosseland opacity for iron, which was recently measured at the Sandia Z facility, where the temperature reached that prevailing in the convection zone boundary while the density is 2.5 times lower. Finally, we propose a method to measure opacities at solar temperatures and densities that were never reached in the past via laboratory radiation flow experiments, by using plastic foams doped with permilles of dominant photon absorbers in the Sun. The method is advantageous for an experimental study of solar opacities that may lead to a resolution of the solar problem.
↳ astro-ph.SRnucl-thphysics.plasm-phApJ(2018)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE

Nucleon spin and quark content at the physical point

Phenomenological analysis of associated production of Z0+b in the b→J/ψX decay channel at the LHC

The effect of ionic correlations on radiative properties in the solar interior and terrestrial experiments

Affiliations

Phenomenological analysis of associated production of $Z^{0} + b$ in the $b \to J / ψ X$ decay channel at the LHC