Fri·Nov 6, 2020Friday·November 6, 2020

1. 01*

   Weinberg operator contribution to the nucleon electric dipole moment in the quark model

   Nodoka Yamanaka🇺🇸 · Emiko Hiyama🇯🇵

   We evaluate the contribution of the CP violating gluon chromo-electric dipole moment (the so-called Weinberg operator, denoted as $w$) to the electric dipole moment (EDM) of nucleons in the nonrelativistic quark model. The CP-odd interquark potential is modeled by the perturbative one-loop level gluon exchange generated by the Weinberg operator with massive quarks and gluons. The nucleon EDM is obtained by solving the nonrelativistic Schrödinger equation of the three-quark system using the Gaussian expansion method. It is found that the resulting nucleon EDM, which may reasonably be considered as the irreducible contribution, is smaller than the one obtained after ${\gamma }_5$-rotating the anomalous magnetic moment using the CP-odd mass calculated with QCD sum rules. We estimate the total contribution to be $d_n=w\times 20e\mathrm{MeV}$ and $d_p=-w\times 18e\mathrm{MeV}$ with 60% of theoretical uncertainty.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2021)·39 citations
2. 02*

   Folding model approach to the elastic $p{+}^{12,13}$C scattering at low energies and radiative capture ${}^{12,13}$C$(p,\gamma )$ reactions

   Nguyen Le Anh · Nguyen Hoang Phuc🇻🇳 · Dao T. Khoa🇻🇳 · Le Hoang Chien · Nguyen Tri Toan Phuc🇻🇳

   The proton radiative capture ${}^{12,13}$C$(p,\gamma )$ reactions at astrophysical energies, key processes in the CNO cycle, are revisited in the potential model with the proton-nucleus potential for both the scattering and bound states obtained in the folding model, using a realistic density dependent nucleon-nucleon interaction. For the consistency, this same folding model is also used to calculate the optical potential of the elastic $p{+}^{12,13}$C scattering at energies around the Coulomb barrier. The folded $p{+}^{12,13}$C optical potentials are shown to account well for both the elastic $p{+}^{12,13}$C3 scattering and astrophysical $S$ factors of the radiative capture ${}^{12,13}$C$(p,\gamma )$ reactions.

   ↳ nucl-thnucl-exNPA(2021)·5 citations
3. 03*

   HERA data on azimuthal decorrelation and charged particle multiplicity spectra probing QCD dynamics and quantum entanglement effects

   Zhoudunming Tu (for the H1 and ZEUS Collaborations)🇺🇸

   The azimuthal decorrelation angle between the leading jet and scattered lepton in deep inelastic scattering is studied with the ZEUS detector at HERA. The data was taken in the HERA II data-taking period and corresponds to an integrated luminosity of 330 $\mathrm{p}{\mathrm{b}}^{-1}$. Azimuthal angular decorrelation has been proposed to study the $Q^2$ dependence of the evolution of the transverse momentum distributions (TMDs) and understand the small-$x$ region, providing unique insight to nucleon structure. Previous decorrelation measurements of two jets have been performed in proton-proton collisions at very high transverse momentum; these measurements are well described by perturbative QCD at next-to-leading order. The azimuthal decorrelation angle obtained in these studies shows good agreement with predictions from Monte Carlo models including leading order matrix elements and parton showers. New experimental data on charged particle multiplicity distributions are presented, covering the kinematic ranges in momentum transfer $5<Q^2<100\mathrm{Ge}{\mathrm{V}}^2$ and inelasticity $0.0375<y<0.6$. The data was recorded with the H1 experiment at the HERA collider in positron-proton collisions at a centre-of-mass energy of 320 GeV. Charged particles are counted with transverse momenta larger than 150 MeV and pseudorapidity $-1.6<{\eta }_{\mathrm{lab}}<1.6$ in the laboratory frame, corresponding to high acceptance in the current hemisphere of the hadronic centre-of-mass frame. Charged particle multiplicities are reported on a two-dimensional grid of $Q^2$, $y$ and on a three-dimensional grid of $Q^2$, $y$ and $\eta$. The observable is the probability $P(N)$ to observe $N$ particles in the given $\eta$ region. The data are confronted with predictions from Monte Carlo generators, and with a simplistic model based on quantum entanglement and strict parton-hadron duality.

   ↳ hep-exhep-phnucl-exPoS(2021)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.