Mon·Nov 27, 2017Monday·November 27, 2017

1. 01*

   Semilocal momentum-space regularized chiral two-nucleon potentials up to fifth order

   P. Reinert🇩🇪 · H. Krebs🇩🇪 · E. Epelbaum🇩🇪

   We introduce new semilocal two-nucleon potentials up to fifth order in the chiral expansion. We employ a simple regularization approach for the pion-exchange contributions which (i) maintains the long-range part of the interaction, (ii) is implemented in momentum space and (iii) can be straightforwardly applied to regularize many-body forces and current operators. We discuss in detail the two-nucleon contact interactions at fourth order and demonstrate that three terms out of fifteen used in previous calculations can be eliminated via suitably chosen unitary transformations. The removal of the redundant contact terms results in a drastic simplification of the fits to scattering data and leads to interactions which are much softer (i.e. more perturbative) than our recent semilocal coordinate-space regularized potentials. Using the pion-nucleon low-energy constants from matching pion-nucleon Roy-Steiner equations to chiral perturbation theory, we perform a comprehensive analysis of nucleon-nucleon scattering and the deuteron properties up to fifth chiral order and study the impact of the leading F-wave two-nucleon contact interactions which appear at sixth order. The resulting chiral potentials lead to an outstanding description of the proton-proton and neutron-proton scattering data from the self-consistent Granada-2013 database below the pion production threshold, which is significantly better than for any other chiral potential. For the first time, the chiral potentials match in precision and even outperform the available high-precision phenomenological potentials, while the number of adjustable parameters is, at the same time, reduced by about ~40%. Last but not least, we perform a detailed error analysis and, in particular, quantify for the first time the statistical uncertainties of the fourth- and the considered sixth-order contact interactions.

   ↳ nucl-thhep-phnucl-exEPJA(2018)·369 citations
2. 02*

   Measurement of emission angle anisotropy via long-range angular correlations with high $p_T$ hadrons in $d$$+$Au and $p$$+$$p$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV

   A. Adare🇺🇸 · C. Aidala🇺🇸 · N.N. Ajitanand🇺🇸 · Y. Akiba🇯🇵 · H. Al-Bataineh🇺🇸 · J. Alexander🇺🇸 · M. Alfred🇺🇸 · A. Angerami🇺🇸 · K. Aoki🇯🇵 · N. Apadula🇺🇸 · Y. Aramaki🇯🇵 · E.T. Atomssa🇫🇷 and 463 other authors

   We present measurements of two-particle angular correlations between high-transverse-momentum ($2<p_T<11$ GeV/$c$) ${\pi }^0$ observed at midrapidity ($|\eta |<0.35$) and particles produced either at forward ($3.1<\eta <3.9$) or backward ($-3.7<\eta <-3.1$) rapidity in $d$$+$Au and $p$$+$$p$ collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV. The azimuthal angle correlations for particle pairs with this large rapidity gap in the Au-going direction exhibit a ridge-like structure that persists up to $p_T\approx 6$ GeV/$c$ and which strongly depends on collision centrality, which is a similar characteristic to the hydrodynamical particle flow in A+A collisions. The ridge-like structure is absent in the $d$-going direction as well as in $p$$+$$p$ collisions, in the transverse-momentum range studied. The results indicate that the ridge-like structure is shifted in the Au-going direction toward more central collisions, similar to the charged-particle pseudorapidity distributions.

   ↳ hep-exnucl-exPRC(2018)·11 citations
3. 03*

   Drag Induced Radiation and Multi-Stage Effects in Heavy-Flavor Energy Loss

   Shanshan Cao🇺🇸 · Abhijit Majumder🇺🇸 · Guang-You Qin🇨🇳 · Chun Shen🇺🇸

   It is argued that heavy-quarks traversing a Quark Gluon Plasma, undergo a multi-stage modification process, similar to the case of light flavors. Such an approach is applied to heavy-quark energy loss, which includes a rare-scattering, multiple emission formalism at momenta large compared to the mass (sensitive only to the transverse diffusion coefficient $\hat{q}$), and a single scattering induced emission formalism (Gunion-Bertsch) at momenta comparable to the mass of the quark [sensitive to $\hat{q}$, and the longitudinal drag ($\hat{e}$) and diffusion (${\hat{e}}_2$) coefficients]. The application of such a multi-stage approach within a 2+1D viscous fluid-dynamical simulation leads to simultaneous agreement with experimental data for the nuclear modification factor of both $B$ and $D$ mesons, as measured by the CMS collaboration at the LHC. The extracted transport coefficients are found to be consistent with those for light flavors.

   ↳ nucl-thhep-phnucl-exPLB(2019)·22 citations
4. 04*

   Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations

   N. Nishimura🇬🇧 · T. Rauscher🇬🇧 · R. Hirschi🇬🇧 · A. St. J. Murphy🇬🇧 · G. Cescutti · C. Travaglio🇮🇹

   Thermonuclear supernovae originating from the explosion of a white dwarf accreting mass from a companion star have been suggested as a site for the production of $p$ nuclides. Such nuclei are produced during the explosion, in layers enriched with seed nuclei coming from prior strong $s$ processing. These seeds are transformed to proton-richer isotopes mainly by photodisintegration reactions. Several thousand trajectories from a 2D explosion model were used in a Monte Carlo approach. Temperature-dependent uncertainties were assigned individually to thousands of rates varied simultaneously in post-processing in an extended nuclear reaction network. The uncertainties in the final nuclear abundances originating from uncertainties in the astrophysical reaction rates were determined. In addition to the 35 classical $p$ nuclides, abundance uncertainties were also determined for the radioactive nuclides ${}^{92}$Nb, ${}^{97,98}$Tc, ${}^{146}$Sm, and for the abundance ratios $Y$(${}^{92}$Mo)/$Y$(${}^{94}$Mo), $Y$(${}^{92}$Nb)/$Y$(${}^{92}$Mo), $Y$(${}^{97}$Tc)/$Y$(${}^{98}$Ru), $Y$(${}^{98}$Tc)/$Y$(${}^{98}$Ru), and $Y$(${}^{146}$Sm)/$Y$(${}^{144}$Sm), important for Galactic Chemical Evolution studies. Uncertainties found were generally lower than a factor of two, although most nucleosynthesis flows mainly involve predicted rates with larger uncertainties. The main contribution to the total uncertainties comes from a group of trajectories with high peak density originating from the interior of the exploding white dwarf. The distinction between low-density and high-density trajectories allows more general conclusions to be drawn, also applicable to other simulations of white dwarf explosions.

   ↳ astro-ph.SRnucl-exnucl-thMNRAS(2018)·47 citations
5. 05*

   Parton distribution amplitudes: revealing diquarks in the proton and Roper resonance

   Cedric Mezrag🇮🇹 · Jorge Segovia🇪🇸 · Lei Chang🇨🇳 · Craig D. Roberts🇺🇸

   We present the first quantum field theory calculation of the pointwise behaviour of the leading-twist parton distribution amplitudes (PDAs) of the proton and its lightest radial excitation. The proton's PDA is a broad, concave function, whose maximum is shifted relative to the peak in QCD's conformal limit expression for this PDA; an effect which signals the presence of both scalar and pseudovector diquark correlations in the nucleon, with the scalar generating around 60% of the proton's normalisation. The radial-excitation is constituted similarly, and the pointwise form of its PDA, which is negative on a material domain, is the result of marked interference between the contributions from both types of diquark; particularly, the locus of zeros that highlights its character as a radial excitation. These features originate with the emergent phenomenon of dynamical chiral-symmetry breaking in the Standard Model.

   ↳ nucl-thhep-lathep-phnucl-exPLB(2018)·45 citations

* 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.