Tue·Jan 30, 2018Tuesday·January 30, 2018

1. 01*

   Reexamining the iconic dihadron correlation measurement demonstrating jet quenching

   Christine Nattrass🇺🇸

   Early measurements at the Relativistic Heavy Ion Collider (RHIC) demonstrated jet quenching through the suppression of pairs of high momentum hadrons. These dihadron correlations have a large correlated background. As understanding of the background improved, it was recognized in the field that a significant term was omitted from the background and several dihadron correlation results were quantitatively and qualitatively incorrect. The original measurements demonstrating jet quenching have not been revisited. These measurements are repeated in this paper in a kinematic range similar to the original measurement using publicly available data, applying current knowledge about the background. The new results are qualitatively consistent with the previous results, demonstrating complete suppression of the away-side within uncertainties.

   nucl-exPRC(2018)·1 citation
2. 02*

   Understanding the Low-Energy Enhancement of the $\gamma$-ray Strength Function of ${}^{56}$Fe

   M.D. Jones🇺🇸 · A.O. Macchiavelli🇺🇸 · M. Wiedeking🇿🇦 · L.A. Bernstein🇺🇸 · H.L. Crawford🇺🇸 · C.M. Campbell🇺🇸 · R.M. Clark🇺🇸 · M. Cromaz🇺🇸 · P. Fallon🇺🇸 · I.Y. Lee🇺🇸 · M. Salathe🇺🇸 · A. Wiens🇺🇸 and 18 other authors

   A model-independent technique was used to determine the $\gamma$-ray Strength Function ($\gamma$SF) of ${}^{56}$Fe down to $\gamma$-ray energies less than 1 MeV for the first time with GRETINA using the $(p,p^{\prime })$ reaction at 16 MeV. No difference was observed in the energy dependence of the $\gamma$SF built on $2^{+}$ and $4^{+}$ final states, supporting the Brink hypothesis. In addition, angular distribution and polarization measurements were performed. The angular distributions are consistent with dipole radiation. The polarization results show a small bias towards magnetic character in the region of the enhancement.

   nucl-exPRC(2018)·40 citations
3. 03*

   How hadron collider experiments contributed to the development of QCD: from hard-scattering to the perfect liquid

   M.J.Tannenbaum🇺🇸

   A revolution in elementary particle physics occurred during the period from the ICHEP1968 to the ICHEP1982 with the advent of the parton model from discoveries in Deeply Inelastic electron-proton Scattering at SLAC, neutrino experiments, hard-scattering observed in p$+$p collisions at the CERN ISR, the development of QCD, the discovery of the J/$\Psi$ at BNL and SLAC and the clear observation of high transverse momentum jets at the CERN SPS $\bar{p}+p$ collider. These and other discoveries in this period led to the acceptance of QCD as the theory of the strong interactions. The desire to understand nuclear physics at high density such as in neutron stars led to the application of QCD to this problem and to the prediction of a Quark-Gluon Plasma (QGP) in nuclei at high energy density and temperatures. This eventually led to the construction of the Relativistic Heavy Ion Collider (RHIC) at BNL to observe superdense nuclear matter in the laboratory. This article discusses how experimental methods and results which confirmed QCD at the first hadron collider, the CERN ISR, played an important role in experiments at the first heavy ion collider, RHIC, leading to the discovery of the QGP as a perfect liquid as well as discoveries at RHIC and the LHC which continue to the present day.

   ↳ hep-exnucl-exEur.Phys.J.H(2018)·2 citations
4. 04*

   Gamow-Teller transitions from high-spin isomers in $N=Z$ nuclei

   H. Z. Liang🇯🇵 · H. Sagawa🇯🇵 · M. Sasano🇯🇵 · T. Suzuki🇯🇵 · M. Honma🇯🇵

   Gamow-Teller (GT) transitions from high-spin isomers are studied using the sum-rule approach and the shell model. The GT transition strengths from the high-spin isomeric states show a stronger collectivity than those from the ground states in two $N=Z$ nuclei, ${}^{52}$Fe and ${}^{94}$Ag. It is argued that the spin-up and spin-down Fermi spheres involved in the GT transitions from the high-spin isomeric states play important roles. These Fermi spheres are analogous to the isospin-up and isospin-down Fermi spheres for the GT transitions from the ground states in $N>Z$ nuclei and create a strong collectivity.

   ↳ nucl-thnucl-exPRC(2018)·7 citations
5. 05*

   Light nuclei production as a probe of the QCD phase diagram

   Kai-Jia Sun🇨🇳 · Lie-Wen Chen🇨🇳 · Che Ming Ko🇺🇸 · Jie Pu🇨🇳 · Zhangbu Xu🇺🇸

   It is generally believed that the quark-hadron transition at small values of baryon chemical potentials ${\mu }_B$ is a crossover but changes to a first-order phase transition with an associated critical endpoint (CEP) as ${\mu }_B$ increases. Such a ${\mu }_B$-dependent quark-hadron transition is expected to result in a double-peak structure in the collision energy dependence of the baryon density fluctuation in heavy-ion collisions with one at lower energy due to the spinodal instability during the first-order phase transition and another at higher energy due to the critical fluctuations in the vicinity of the CEP. By analyzing the data on the $p$, d and ${}^3$H yields in central heavy-ion collisions within the coalescence model for light nuclei production, we find that the relative neutron density fluctuation $\Delta {\rho }_n=⟨(\delta {\rho }_n{)}^2⟩/⟨{\rho }_n{⟩}^2$ at kinetic freeze-out indeed displays a clear peak at $\sqrt{s_{NN}}=8.8$ GeV and a possible strong re-enhancement at $\sqrt{s_{NN}}=4.86$ GeV. Our findings thus provide a strong support for the existence of a first-order phase transition at large ${\mu }_B$ and its critical endpoint at a smaller ${\mu }_B$ in the temperature versus baryon chemical potential plane of the QCD phase diagram.

   ↳ nucl-thhep-phnucl-exPLB(2018)·129 citations
6. 06*

   Origin of a maximum of astrophysical $S$ factor in heavy-ion fusion reactions at deep subbarrier energies

   K. Hagino🇯🇵 · A.B. Balantekin🇺🇸 · N.W. Lwin · Ei Shwe Zin Thein

   The hindrance phenomenon of heavy-ion fusion cross sections at deep subbarrier energies often accompanies a maximum of an astrophysical $S$ factor at a threshold energy for fusion hindrance. We argue that this phenomenon can naturally be explained when the fusion excitation function is fitted with two potentials, with a larger (smaller) logarithmic slope at energies lower (higher) than the threshold energy. This analysis clearly suggests that the astrophysical $S$ factor provides a convenient tool to analyze the deep subbarrier hindrance phenomenon, even though the $S$ factor may have a strong energy dependence for heavy-ion systems unlike that for astrophysical reactions.

   ↳ nucl-thnucl-exPRC(2018)·6 citations
7. 07*

   Heavy flavour in high-energy nuclear collisions: theory overview of transport calculations

   Andrea Beraudo🇮🇹

   Transport calculations are the tool to study medium modifications of heavy-flavour particle distributions in high-energy nuclear collisions. We give a brief overview on their state-of-the art, on the information one can extract, on the questions remaining open and on further analysis to carry out in the near future.

   ↳ hep-phnucl-exnucl-thFrascati Phys.Ser.(2017)·0 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.