Thu·Oct 31, 2019Thursday·October 31, 2019

1. 01*

   Measurement of ${}^{34}$S(${}^3$He,p)${}^{36}$Cl cross sections for early solar system nuclide enrichment

   Tyler Anderson🇺🇸 · Michael Skulski · Lauren Callahan · Adam Clark🇺🇸 · Austin Nelson🇺🇸 · Philippe Collon · Greg Chmiel · Tom Woodruff · Marc Caffee🇺🇸

   Isotopic studies of meteorites have provided ample evidence for the presence of short-lived radionuclides (SLRs) with half-lives of less than 100 Myr at the time of the formation of the solar system. The origins of all known SLRs is heavily debated and remains uncertain, but the plausible scenarios can be broadly separated into either local production or outside injection of stellar nucleosynthesis products. The SLR production models are limited in part by reliance on nuclear theory for modeling reactions that lack experimental measurements. Reducing uncertainty on critical reaction cross sections can both enable more precise predictions and provide constraints on physical processes and environments in the early solar system. This goal led to the start of a campaign for measuring production cross sections for the SLR ${}^{36}$Cl, where Bowers et al. found higher cross sections for the ${}^{33}$S($\alpha$,p)${}^{36}$Cl reaction than were predicted by Hauser-Feshbach based nuclear reaction codes TALYS and NON-SMOKER. This prompted re-measurement of the reaction at five new energies within the energy range originally studied, resulting in data slightly above but in agreement with TALYS. Following this, efforts began to measure cross sections for the next most significant reaction for ${}^{36}$Cl production, ${}^{34}$S(${}^3$He,p)${}^{36}$Cl. Activations were performed to produce 9 samples between 1.11 MeV/nucleon and 2.36 MeV/nucleon. These samples were subsequently measured with accelerator mass spectrometry at two labs. The resulting data suggest a sharper-than-expected rise in cross sections with energy, with peak cross sections up to 30\% higher than predictions from TALYS.

   nucl-exPRC(2020)·2 citations
2. 02*

   Analyzing powers in $d(\vec{p},pp)n$ at intermediate and large scattering angles at $190$~MeV

   M. Mohammadi-Dadkan🇳🇱 · H.R. Amir-Ahmadi🇳🇱 · M.T. Bayat · A. Deltuva🇱🇹 · M. Eslami-Kalantari🇮🇷 · J. Golak🇵🇱 · N. Kalantar-Nayestanaki🇳🇱 · St. Kistryn🇵🇱 · A. Kozela🇵🇱 · H. Mardanpour🇳🇱 · A.A. Mehmandoost-Khajeh-dad · J.G. Messchendorp🇳🇱 and 6 other authors

   Understanding of the exact nature of three-nucleon forces is the most challenging topic in the field of nuclear physics. Three-nucleon break-up reaction is a good tool to look into the underlying dynamics of the nuclear force, thanks to its rich kinematical phase space which has different levels of sensitivity to three-nucleon force effects. The recent studies on few-nucleon systems have revealed that the current nuclear force models cannot describe nucleon-deuteron scattering data accurately. In the present work, the analyzing powers of the proton-deuteron break-up reaction obtained using a 190 MeV polarized proton beam will be discussed. We present for the first time the vector analyzing powers for the kinematics in which one of the protons scatters to intermediate and large scattering angles at this energy. The results show a fairly good agreement with various theoretical predictions for both intermediate and large scattering angles of the break-up phase space.

   nucl-exEPJA(2020)·6 citations
3. 03*

   Transverse momentum and process dependent azimuthal anisotropies in $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV $p$+Pb collisions with the ATLAS detector

   ATLAS Collaboration

   The azimuthal anisotropy of charged particles produced in $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV $p$+Pb collisions is measured with the ATLAS detector at the LHC. The data correspond to an integrated luminosity of $165$ ${\mathrm{nb}}^{-1}$ that was collected in 2016. Azimuthal anisotropy coefficients, elliptic $v_2$ and triangular $v_3$, extracted using two-particle correlations with a non-flow template fit procedure, are presented as a function of particle transverse momentum ($p_{\mathrm{T}}$) between $0.5$ and $50$ GeV. The $v_2$ results are also reported as a function of centrality in three different particle $p_{\mathrm{T}}$ intervals. The results are reported from minimum-bias events and jet-triggered events, where two jet $p_{\mathrm{T}}$ thresholds are used. The anisotropies for particles with $p_{\mathrm{T}}$ less than about $2$ GeV are consistent with hydrodynamic flow expectations, while the significant non-zero anisotropies for $p_{\mathrm{T}}$ in the range $9$-$50$ GeV are not explained within current theoretical frameworks. In the $p_{\mathrm{T}}$ range $2$-$9$ GeV, the anisotropies are larger in minimum-bias than in jet-triggered events. Possible origins of these effects, such as the changing admixture of particles from hard scattering and the underlying event, are discussed.

   nucl-exhep-exEPJC(2020)·74 citations
4. 04*

   Fission in a microscopic framework: from basic science to support for applications

   I. Stetcu🇺🇸 · A. Bulgac🇺🇸 · S. Jin🇨🇳 · K. J. Roche · N. Schunck🇺🇸

   Recent developments, both in theoretical modeling and computational power, have allowed us to make progress on a goal not fully achieved yet in nuclear theory: a microscopic theory of nuclear fission. Even if the complete microscopic description remains a computationally demanding task, the information that can be provided by current calculations can be extremely useful to guide and constrain more phenomenological approaches, which are simpler to implement. First, a microscopic model that describes the real-time dynamics of the fissioning system can justify or rule out some of the approximations. Second, the microscopic approach can be used to obtain trends, e.g., with increasing excitation energy of the fissioning system, or even to compute observables that cannot be otherwise calculated in phenomenological approaches or that can be hindered by the limitations of the method. We briefly present in this contribution the time-dependent superfluid local density approximation (TDSLDA) approach to nuclear fission, approach that has become a very successful theoretical model in many areas of many-body research. The TDSLDA incorporates the effects of the continuum, the dynamics of the pairing field, and the numerical solution is implemented with controlled approximations and negligible numerical corrections. The main part of the current contribution will be dedicated to discussing the method, and recent results concerning the fission dynamics. In addition, we present results on the excitation energy sharing between the fragments, which are in agreement with a qualitative conclusions extracted from a limited number of experimental measurements of properties of prompt neutrons.

   ↳ nucl-thnucl-exEPJ Web Conf.(2021)·1 citation
5. 05*

   Color transparency of $K^{+}$ meson produced in the inclusive $(e,e^{\prime })$ reaction on nuclei

   Swapan Das🇮🇳

   Color transparency is studied for the $K^{+}$ meson produced due to large four-momentum transfer in the $(e,e^{\prime })$ reaction on nuclei. The variation of the $K^{+}$ meson color transparency ($K^{+}$CT) with the photon virtuality, and kaon momentum is investigated. The calculated results for $K^{+}$CT are compared with the data reported from Jefferson Laboratory.

   ↳ nucl-thnucl-exPRC(2019)·5 citations
6. 06*

   Nuclear deformation effects on charge radius measurements of the proton and deuteron

   Yonghui Lin🇨🇳 · Bingsong Zou🇨🇳

   Up to now, all charge radius measurements of the proton and deuteron assumed uniform spheroidal charge distribution. We investigate the nuclear deformation effects on these charge radius measurements by assuming a uniform prolate charge distribution for the proton and deuteron. We solve the energy levels of the corresponding muonic and electric atoms with such deformed nucleus and present how the purely quadruple deformation of proton and deuteron affects their Lamb shifts. The numerical results suggest that the deformation of proton and deuteron leads to that the charge radius extracted from the electronic measurement should be smaller than the corresponding one in the muonic measurement which assumed uniform spheroidal charge distribution. If the central values of newest measurements for the proton are adopted, the proton would have a prolate structure with the 0.91 $\mathrm{fm}$ long axis and 0.73 $\mathrm{fm}$ short axis. Further improved precise charge radius measurements of the proton and deuteron will help us to pin down their shape deformation.

   ↳ hep-phnucl-exnucl-th1 citation
7. 07*

   Signatures of Chiral Magnetic Effect in the Collisions of Isobars

   Shuzhe Shi🇨🇦 · Hui Zhang🇨🇳 · Defu Hou🇨🇳 · Jinfeng Liao🇺🇸

   Quantum anomaly is a fundamental feature of chiral fermions. In chiral materials the microscopic anomaly leads to nontrivial macroscopic transport processes such as the Chiral Magnetic Effect (CME), which has been in the spotlight lately across disciplines of physics. The quark-gluon plasma (QGP) created in relativistic nuclear collisions provides the unique example of a chiral material consisting of intrinsically relativistic chiral fermions. Potential discovery of CME in QGP is of utmost significance, with extensive experimental searches carried out over the past decade. A decisive new collider experiment, dedicated to detecting CME in the collisions of isobars, was performed in 2018 with analysis now underway. In this paper, we develop the state-of-the-art theoretical tool for describing CME phenomenon in these collisions and propose an appropriate isobar subtraction strategy for best background removal. Based on that, we make quantitative predictions for signatures of CME in the collisions of isobars. A new and robust observable that is independent of axial charge uncertainty -- the ratio between isobar-subtracted $\gamma -$ and $\delta -$ correlators, is found to be $-(0.41\pm 0.27)$ for event-plane measurement and $-(0.90\pm 0.45)$ for reaction-plane measurement.

   ↳ nucl-thhep-phnucl-exPRL(2020)·69 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.