Fri·May 4, 2018Friday·May 4, 2018

1. 01*

   Activation cross-sections of proton induced reactions on ${}^{nat}$Hf in the 38 to 65 MeV energy range. Production of ${}^{172}$Lu and of ${}^{169}$Yb

   F.Tárkányi🇭🇺 · A.Hermanne · F.Ditrói🇭🇺 · S.Takács🇭🇺 · A.V.Ignatyuk🇷🇺

   In the frame of a systematical study of light ion induced nuclear reactions on hafnium, activation cross sections for proton induced reactions were investigated. Excitation functions were measured in the 38 to 65 MeV energy range for the ${}^{nat}$Hf(p,xn)${}^{180g,177,176,175,173}$Ta, ${}^{nat}$Hf(p,x)${}^{180m,179m,175,173,172,171}$Hf, ${}^{177g,173,172,171,170,169}$Lu and ${}^{nat}$Hf(p,x)${}^{169}$Yb reactions by using the activation method, combining stacked foil irradiation and off line gamma ray spectroscopy. The experimental results are compared with earlier results in the overlapping energy range, and with the theoretical predictions of the ALICE IPPE and EMPIRE theoretical codes and of the TALYS code reported in the TENDL2015 and TENDL2017 libraries. The production routes of ${}^{172}$Lu (and its parent ${}^{172}$Hf) and of ${}^{169Y}$b are reviewed.

   nucl-exNucl.Instrum.Meth.B(2018)·0 citations
2. 02*

   Eta Decay and Muonic Puzzles

   Yu-Sheng Liu🇨🇳 · Ian C. Cloët🇺🇸 · Gerald A. Miller🇺🇸

   New physics motivated by muonic puzzles (proton radius and muon $g-2$ discrepancies) is studied. Using a light scalar boson $\varphi$, assuming Yukawa interactions, accounts for these muonic puzzles simultaneously. Our previous work limits the existence of such a scalar boson's mass $m_{\varphi }$ from about 160 keV to 60 MeV. We improve this result by including the influence of all of the possible particles that couple to the $\varphi$ in computing the decay rate. Doing this involves including the strong interaction physics, involving quarks, necessary to compute the $\eta \pi \varphi$ vertex function. The Nambu-Jona-Lasinio model, which accounts for the spontaneous symmetry breaking that yields the constituent mass is employed to represent the relevant strong-interaction physics. We use the $\eta \pi \varphi$ vertex function to reanalyze the electron beam dump experiments. The result is that the allowed range of $m_{\varphi }$ lies between about 160 keV and 3.5 MeV. This narrow range represents an inviting target for ruling out or discovering this scalar boson. A possible UV completion of our phenomenological model is discussed.

   ↳ hep-phhep-exnucl-exnucl-th+1NPB(2019)·11 citations
3. 03*

   Uncertainties in s-process nucleosynthesis in low mass stars determined from Monte Carlo variations

   G. Cescutti · R. Hirschi🇬🇧 · N. Nishimura🇬🇧 · J. W. den Hartogh · T. Rauscher🇬🇧 · A. St. J. Murphy🇬🇧 · S. Cristallo🇮🇹

   The main s-process taking place in low mass stars produces about half of the elements heavier than iron. It is therefore very important to determine the importance and impact of nuclear physics uncertainties on this process. We have performed extensive nuclear reaction network calculations using individual and temperature-dependent uncertainties for reactions involving elements heavier than iron, within a Monte Carlo framework. Using this technique, we determined the uncertainty in the main s-process abundance predictions due to nuclear uncertainties link to weak interactions and neutron captures on elements heavier than iron. We also identified the key nuclear reactions dominating these uncertainties. We found that $\beta$-decay rate uncertainties affect only a few nuclides near s-process branchings, whereas most of the uncertainty in the final abundances is caused by uncertainties in neutron capture rates, either directly producing or destroying the nuclide of interest. Combined total nuclear uncertainties due to reactions on heavy elements are in general small (less than 50%). Three key reactions, nevertheless, stand out because they significantly affect the uncertainties of a large number of nuclides. These are ${}^{56}$Fe(n,$\gamma$), ${}^{64}$Ni(n,$\gamma$), and ${}^{138}$Ba(n,$\gamma$). We discuss the prospect of reducing uncertainties in the key reactions identified in this study with future experiments.

   ↳ astro-ph.SRnucl-exnucl-thMNRAS(2018)·32 citations
4. 04*

   New exact solutions of relativistic hydrodynamics for longitudinally expanding fireballs

   T. Csorgo🇭🇺 · G. Kasza🇭🇺 · M. Csanad🇭🇺 · Z. Jiang🇨🇳

   We present new, exact, finite solutions of relativistic hydrodynamics for longitudinally expanding fireballs for arbitrary constant value of the speed of sound. These new solutions generalize earlier, longitudinally finite, exact solutions, from an unrealistic to a reasonable equation of state, characterized by a temperature independent (average) value of the speed of sound. Observables like the rapidity density and the pseudorapidity density are evaluated analytically, resulting in simple and easy to fit formulae that can be matched to the high energy proton-proton and heavy ion collision data at RHIC and LHC. In the longitudinally boost-invariant limit, these new solutions approach the Hwa-Bjorken solution and the corresponding rapidity distributions approach a rapidity plateaux.

   ↳ nucl-thhep-exhep-phnucl-exUniverse(2018)·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.