Tue·Dec 20, 2016Tuesday·December 20, 2016

1. 01*

   Nucleon spin structure studies at Jefferson Lab

   A. Deur🇺🇸

   We report on the low and moderate Q^2 nucleon spin structure measurements done at Jefferson Lab, examining specifically the inclusive program. We discuss what the data teach us about quark confinement and the emergence of the effective hadronic degrees of freedom from the fundamental partonic ones. We show how this experimental program has reached its goal by providing a precise mapping at low, intermediate and moderately high Q^2 which has followed in many advances, e.g., with Chiral Perturbation Theory. Another example of a recent advance imputable to the JLab spin data is the improved understanding of \alpha_s at low energy, which allowed Light-Front Holographic QCD, an approximation to non-perturbative QCD, to derive the hadron spectrum from \Lambda_s.

   nucl-exhep-phnucl-th0 citations
2. 02*

   Heavy meson flow harmonics in event-by-event viscous relativistic hydrodynamics

   Caio A. G. Prado🇧🇷 · Jacquelyn Noronha-Hostler🇺🇸 · Jorge Noronha🇧🇷 · Alexandre A. P. Suaide🇧🇷 · Marcelo G. Munhoz🇧🇷 · Mauro R. Cosentino🇧🇷

   Event-by-event viscous hydrodynamics is combined with heavy quark energy loss models to compute heavy flavor flow cumulants $v_2\{2\}$, $v_3\{2\}$, and $v_2\{4\}$ as well as the nuclear modification factors of $D^0$ and $B^0$ mesons in PbPb collisions at 2.76 TeV. Our results indicate that bottom quarks can flow as much as charm quarks in the $p_T$ range 8--30 GeV.

   ↳ nucl-thhep-phnucl-exNucl.Part.Phys.Proc.(2017)·3 citations
3. 03*

   EPPS16: Nuclear parton distributions with LHC data

   Kari J. Eskola🇫🇮 · Petja Paakkinen🇫🇮 · Hannu Paukkunen🇫🇮 · Carlos A. Salgado🇪🇸

   We introduce a global analysis of collinearly factorized nuclear parton distribution functions (PDFs) including, for the first time, data constraints from LHC proton-lead collisions. In comparison to our previous analysis, EPS09, where data only from charged-lepton-nucleus deep inelastic scattering (DIS), Drell-Yan (DY) dilepton production in proton-nucleus collisions and inclusive pion production in deuteron-nucleus collisions were the input, we now increase the variety of data constraints to cover also neutrino-nucleus DIS and low-mass DY production in pion-nucleus collisions. The new LHC data significantly extend the kinematic reach of the data constraints. We now allow much more freedom for the flavour dependence of nuclear effects than in other currently available analyses. As a result, especially the uncertainty estimates are more objective flavour by flavour. The neutrino DIS plays a pivotal role in obtaining a mutually consistent behaviour for both up and down valence quarks, and the LHC dijet data clearly constrain gluons at large momentum fraction. Mainly for insufficient statistics, the pion-nucleus DY and heavy gauge boson production in proton-lead collisions impose less visible constraints. The outcome - a new set of next-to-leading order nuclear PDFs called EPPS16 - is made available for applications in high-energy nuclear collisions.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2017)·745 citations
4. 04*

   Exclusive heavy vector meson photoproduction in hadronic collisions at the LHC: predictions of the Color Glass Condensate model for Run 2 energies

   V. P. Goncalves🇧🇷 · B. D. Moreira🇧🇷 · F. S. Navarra🇧🇷

   In this letter we update our predictions for exclusive $J/\Psi$ and ${\rm Y}$ photoproduction in proton-proton and nucleus - nucleus collisions at the Run 2 LHC energies obtained with the color dipole formalism and considering the impact parameter Color Glass Condensate model (bCGC) for the forward dipole - target scattering amplitude. A comparison with the LHCb data on rapidity distributions and photon - hadron cross sections is presented. Our results demonstrate that the current data can be quite well described by the bCGC model, which takes into account nonlinear effects in the QCD dynamics and reproduces the very precise HERA data, without introducing any additional effect or free parameter.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2017)·29 citations
5. 05*

   Correlated wounded hot spots in proton-proton interactions

   Javier L. Albacete🇪🇸 · Hannah Petersen🇩🇪 · Alba Soto-Ontoso🇪🇸

   We investigate the effect of non-trivial spatial correlations between proton constituents, considered in this work to be gluonic hot spots, on the initial conditions of proton-proton collisions from ISR to LHC energies, i.e. $\sqrt{s}=52.6,7000,13000$ GeV. The inclusion of these correlations is motivated by their fundamental role in the description of a recently observed new feature of $pp$ scattering at $\sqrt{s}=7$ TeV, the hollowness effect. Our analysis relies on a Monte-Carlo Glauber approach including fluctuations in the hot spot positions and their entropy deposition in the transverse plane. We explore both the energy dependence and the effect of spatial correlations on the number of wounded hot spots, their spatial distribution and the eccentricities, ${\epsilon }_n$, of the initial state geometry of the collision. In minimum bias collisions we find that the inclusion of short range repulsive correlations between the hot spots reduces the value of the eccentricity (${\epsilon }_2$) and the triangularity (${\epsilon }_3$). In turn, upon considering only the events with the highest entropy deposition i.e. the ultra-central ones, the probability of having larger ${\epsilon }_{2,3}$ increases significantly in the correlated scenario. Finally, the eccentricities show a quite mild energy dependence.

   ↳ hep-phnucl-exnucl-thPRC(2017)·22 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.