Thu·Jun 28, 2018Thursday·June 28, 2018

1. 01*

   Energy and momentum dependence of nuclear short-range correlations - Spectral function, exclusive scattering experiments and the contact formalism

   Ronen Weiss🇮🇱 · Igor Korover🇮🇱 · Eliezer Piasetzky🇮🇱 · Or Hen🇺🇸 · Nir Barnea🇮🇱

   Results of electron-induced one- and two-nucleon hard knockout reactions, $A(e,e^{\prime }p)$ and $A(e,e^{\prime }pN)$, in kinematics sensitive to nuclear short-range correlations, are studied using the nuclear contact formalism. A relation between the spectral function and the nuclear contacts is derived and used to analyze the dependence of the data on the initial energy and momentum of the knocked-out proton. The ratio between the number of emitted proton-proton pairs and proton-neutron pairs is shown to depend predominantly on a single ratio of contacts. This ratio is expected to present a deep minima in the initial energy and momentum plane, associated with the node in the proton-proton wave function. The formalism is applied to analyze data from recent ${}^4$He and ${}^{12}$C electron-scattering experiments performed at Jefferson laboratory. Different nucleon-nucleon potentials were used to asses the model-dependence of the results. For the ratio of proton-proton to proton-neutron pairs in ${}^4$He, a fair agreement with the experimental data is obtained using the two potentials, whereas for the ratio of proton-proton pairs to the total knocked-out protons in ${}^{12}$C, some of the features of the theory are not seen in the experimental data. Several possible explanations for this disagreement are discussed. It is also observed that the spectral function at specific domains of the momentum-energy plane is sensitive to the nucleon-nucleon interaction. Based on this sensitivity, it might be possible to constrain the short range part of the nuclear potential using such experimental data.

   ↳ nucl-thnucl-exPLB(2019)·54 citations
2. 02*

   Enhancement of strange baryons in high-multiplicity proton-proton and proton-nucleus collisions

   Yuuka Kanakubo🇯🇵 · Michito Okai🇯🇵 · Yasuki Tachibana🇺🇸 · Tetsufumi Hirano🇯🇵

   We investigate the enhancement of yields of strange and multi-strange baryons in proton-proton (p+p), proton-lead (p+Pb) and lead-lead (Pb+Pb) collisions at the Large Hadron Collider (LHC) energies from a dynamical core-corona initialization model. We first generate partons just after the collisions by using event generators. These partons dynamically generate the quark gluon plasma (QGP) fluids through the source terms in the hydrodynamic equations. According to the core-corona picture, this process tends to happen where the density of generated partons is high and their transverse momentum is low. Some partons do not fully participate in this process when they are in dilute regions or their transverse momentum is high and subsequently fragment into hadrons through string fragmentation. In this framework, the final hadrons come from either chemically equilibrated fluids as in the conventional hydrodynamic models or string fragmentation. We calculate the ratio of strange baryons to charged pions as a function of multiplicity and find that it monotonically increases up to $d{N}_{\mathrm{ch}}/d\eta \sim 100$ and then saturates above. This suggests that the QGP fluids are \textit{partly} created and that their fraction increases with multiplicity in p+p and p+Pb collisions at LHC energies.

   ↳ nucl-thhep-phnucl-exPTEP(2018)·16 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.