Mon·Oct 15, 2018Monday·October 15, 2018

1. 01*

   PHENIX results on collectivity in small systems

   Sylvia Morrow (for the PHENIX collaboration)🇺🇸

   PHENIX has measured elliptic and triangular flow of charged hadrons in $p/d{/}^3$He$+$Au collisions at a center-of-mass energy of 200 GeV per nucleon pair, and elliptic flow in $d$+Au collisions at 200, 62.4, and 39 GeV. In order to asses the origin of collectivity in the smallest systems, these results are compared with several theoretical models that produce azimuthal particle correlations based on initial and/or final state effects. Hydrodynamical models, which include the formation of a droplet of quark-gluon plasma, provide the best simultaneous description of our observations.

   nucl-exhep-ex1 citation
2. 02*

   Direct Observation of Proton-Neutron Short-Range Correlation Dominance in Heavy Nuclei

   M. Duer · A. Schmidt · J.R. Pybus · E.P. Segarra · A.W. Denniston · R. Weiss · O. Hen · E. Piasetzky · L.B. Weinstein · N. Barnea · I. Korover · E. O. Cohen · H. Hakobyan · the CLAS Collaboration

   We measured the triple coincidence A(e,e'np) and A(e,e'pp) reactions on carbon, aluminum, iron, and lead targets at Q2 > 1.5 (GeV/c)2, xB > 1.1 and missing momentum > 400 MeV/c. This was the first direct measurement of both proton-proton (pp) and neutron-proton (np) short-range correlated (SRC) pair knockout from heavy asymmetric nuclei. For all measured nuclei, the average proton-proton (pp) to neutron-proton (np) reduced cross-section ratio is about 6%, in agreement with previous indirect measurements. Correcting for Single-Charge Exchange effects decreased the SRC pairs ratio to ~ 3%, which is lower than previous results. Comparisons to theoretical Generalized Contact Formalism (GCF) cross-section calculations show good agreement using both phenomenological and chiral nucleon-nucleon potentials, favoring a lower pp to np pair ratio. The ability of the GCF calculation to describe the experimental data using either phenomenological or chiral potentials suggests possible reduction of scale- and scheme-dependence in cross section ratios. Our results also support the high-resolution description of high-momentum states being predominantly due to nucleons in SRC pairs.

   nucl-exnucl-thPRL(2019)·135 citations
3. 03*

   Ernest Henley's Isospin and the Ensuing Progress

   Gerald A. Miller🇺🇸

   Ernest Henley's contributions to understanding isospin symmetry and the experimental and theoretical progress that followed are reviewed. Many experimentalists and theorists worked to bring Ernest's early vision of the subject to fruition. This progress and wide-ranging impact is described.

   ↳ nucl-thhep-phnucl-exIJMPE(2018)·0 citations
4. 04*

   An introduction to Bootstrap for nuclear physics

   A. Pastore🇬🇧

   This guide aims at providing a general introduction to bootstrap methods. By using simple examples taken from nuclear physics, I discuss how such a method can be used to quantify error bars of an estimator. I also investigate the use of bootstrap to estimate parameters of a simple liquid drop model. In particular, I investigate how the method compares with standard techniques based on likelihood estimator and how to take into account correlations to better evaluate confidence interval of parameters.

   ↳ nucl-thnucl-exJ.Phys.G(2019)·23 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.