Tue·Nov 22, 2016Tuesday·November 22, 2016

1. 01*

   Shell and explosive hydrogen burning

   A. Boeltzig🇮🇹 · C.G. Bruno🇬🇧 · F. Cavanna🇮🇹 · S. Cristallo🇮🇹 · T. Davinson🇬🇧 · R. Depalo🇮🇹 · R.J. deBoer🇺🇸 · A. Di Leva🇮🇹 · F. Ferraro🇮🇹 · G. Imbriani🇮🇹 · P. Marigo🇮🇹 · F. Terrasi🇮🇹 · M. Wiescher🇺🇸

   The nucleosynthesis of light elements, from helium up to silicon, mainly occurs in Red Giant and Asymptotic Giant Branch stars and Novae. The relative abundances of the synthesized nuclides critically depend on the rates of the nuclear processes involved, often through non-trivial reaction chains, combined with complex mixing mechanisms. In this review, we summarize the contributions made by LUNA experiments in furthering our understanding of nuclear reaction rates necessary for modeling nucleosynthesis in AGB stars and Novae explosions.

   nucl-exEPJA(2016)·24 citations
2. 02*

   Sub-leading flow modes in PbPb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV from HYDJET++ model

   P. Cirkovic🇷🇸 · D. Devetak🇷🇸 · M. Dordevic🇷🇸 · J. Milosevic🇷🇸 · M. Stojanovic🇷🇸

   Recent LHC results on the appearance of sub-leading flow modes in PbPb collisions at 2.76~TeV, related to initial-state fluctuations, are analyzed and interpreted within the HYDJET++ model. Using the newly introduced Principal Component Analysis (PCA) method applied to two-particle azimuthal correlations extracted from the model calculations, the leading and the sub-leading flow modes are studied as a function of the transverse momentum ($p_T$) over a wide centrality range. The leading modes of the elliptic ($v_2^{(1)}$) and triangular ($v_3^{(1)}$) flow calculated within the HYDJET++ model reproduce rather well the $v_2\{2\}$ and $v_3\{2\}$ coefficients experimentally measured using the two-particle correlations. Within the $p_T\le$~3~GeV/c range where hydrodynamics dominates, the sub-leading flow effects are greatest at the highest $p_T$ of around 3~GeV/c. The sub-leading elliptic flow mode ($v_2^{(2)}$), which corresponds to $n=2$ harmonic, has a small non-zero value and slowly increases from central to peripheral collisions, while the sub-leading triangular flow mode ($v_3^{(2)}$), which corresponds to $n=3$ harmonic, is even smaller and does not depend on centrality. For $n=$~2, the relative magnitude of the effect measured with respect to the leading flow mode shows a shallow minimum for semi-central collisions and increases for very central and for peripheral collisions. For $n=$~3 case, there is no centrality dependence. The sub-leading flow mode results obtained from the HYDJET++ model are in a rather good agreement with the experimental measurements of the CMS Collaboration.

   nucl-exCPC(2017)·5 citations
3. 03*

   Half-life of 31Si

   Giancarlo D'Agostino · Marco Di Luzio · Giovanni Mana · Massimo Oddone

   Half-life values are widely used in nuclear chemistry to model the exponential decay of the quantified radionuclides. The analysis of existing data reveals a general lack of information on the performed experiments and an almost complete absence of uncertainty budgets. This is the situation for 31Si, the radionuclide produced via neutron capture reaction recently used to quantify trace amounts of 30Si in a sample of the silicon material highly enriched in 28Si and used for the determination of the Avogadro constant. In order to improve the quality of the now recommended 157.36(26) min value, we carried out repeated observations of the 31Si decay rate via gamma-ray spectrometry measurements. This paper reports the result we obtained, including details of the experiment and the evaluation of the uncertainty.

   nucl-ex0 citations
4. 04*

   A new method to reduce the statistical and systematic uncertainty of chance coincidence backgrounds measured with waveform digitizers

   J.M. O'Donnell

   A new method for measuring chance-coincidence backgrounds during the collection of coincidence data is presented. The method relies on acquiring data with near-zero dead time, which is now realistic due to the increasing deployment of flash electronic-digitizer (waveform digitizer) techniques. An experiment designed to use this new method is capable of acquiring more coincidence data, and a much reduced statistical fluctuation of the measured background. A statistical analysis is presented, and used to derive a figure of merit for the new method. Factors of four improvement over other analyses are realistic. The technique is illustrated with preliminary data taken as part of a program to make new measurements of the prompt fission neutron spectra at Los Alamos Neutron Science Center. It is expected that the these measurements will occur in a regime where the maximum figure of merit will be exploited.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2016)·11 citations
5. 05*

   Latest results on ${\rm Y}$ production in heavy-ion collisions from the STAR experiment

   Robert Vertesi (for the STAR collaboration)🇨🇿

   We report on the latest measurements of the production of ${\rm Y}$ mesons in heavy-ion collisions from the STAR experiment at RHIC. New measurements of the nuclear modification factors of the ${\rm Y}$(1S+2S+3S) and ${\rm Y}$(1S) states in U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV are presented as a function of the number of participants ($N_{part}$) in the collisions. In addition, the suppression of ${\rm Y}$(1S) and ${\rm Y}$(2S+2S) is presented versus the quark-antiquark binding energy. Preliminary results on Upsilon suppression in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV, reconstructed via the dimuon channel, are also reported.

   ↳ hep-exnucl-exJ.Phys.Conf.Ser.(2017)·0 citations
6. 06*

   Exotic-Hadron Signature by Constituent-Counting Rule in Perturbative QCD

   Wen-Chen Chang🇹🇼 · H. Kawamura🇯🇵 · S. Kumano🇯🇵 · T. Sekihara🇯🇵

   We explain a method to find internal quark configurations of exotic hadron candidates by using the constituent counting rule. The counting rule was theoretically predicted in perturbative QCD for hard exclusive hadron reactions, and it has been tested in experiments for stable hadrons including compound systems of hadrons such as the deuteron, ${}^3$H, and ${}^3$He. It indicates that the cross section scales as $d\sigma /dt\sim 1/s^{n-2}$, where $s$ is the center-of-mass energy squared and $n$ is the total number of constituents. We apply this method for finding internal configurations of exotic hadron candidates, especially $\Lambda (1405)$. There is a possibility that $\Lambda (1405)$ could be five-quark state or a $\bar{K}N$ molecule, and scaling properties should be different between the ordinary three-quark state or five-quark one. We predict such a difference in ${\pi }^{-}+p\to K^0+\Lambda (1405)$, and it could be experimentally tested, for example, at J-PARC. On the other hand, there are already measurements for $\gamma +p\to K^{+}+\Lambda (1405)$ as well as the ground $\Lambda$ in photoproduction reactions. Analyzing such data, we found an interesting indication that $\Lambda (1405)$ looks like a five-quark state at medium energies and a three-quark one at high energies. However, accurate higher-energy measurements are necessary for drawing a solid conclusion, and it should be done at JLab by using the updated 12 GeV electron beam. Furthermore, we discuss studies of exotic hadron candidates, such as $f_0(980)$ and $a_0(980)$, in electron-positron annihilation by using generalized distribution amplitudes and the counting rule. These studies should be possible as a KEKB experiment.

   ↳ hep-phhep-exhep-latnucl-ex+1JPS Conf.Proc.(2017)·1 citation
7. 07*

   The extraction of parameters from final state interactions

   G.Faldt🇸🇪 · C.Wilkin🇬🇧

   It is argued that final state enhancements in production reactions at large momentum transfers, such as pp -> K^+ Lambda p, are primarily sensitive to the position of a virtual bound state pole in the Lambda p system rather than the Lambda p scattering length and effective range. These arguments are supported by a study of the dispersion relation derived to describe such processes as a function of the cut-off energy. This shows that the position of the virtual bound state is independent of the cut-off energy.

   ↳ nucl-thnucl-exPRC(2017)·3 citations
8. 08*

   Computational Nuclear Physics and Post Hartree-Fock Methods

   Justin Lietz (MSU)🇺🇸 · Sam Novario (MSU)🇺🇸 · Gustav R. Jansen (ORNL)🇺🇸 · Gaute Hagen (ORNL)🇺🇸 · Morten Hjorth-Jensen (MSU and University of Oslo)🇺🇸

   We present a computational approach to infinite nuclear matter employing Hartree-Fock theory, many-body perturbation theory and coupled cluster theory. These lectures are closely linked with those of chapters 9, 10 and 11 and serve as input for the correlation functions employed in Monte Carlo calculations in chapter 9, the in-medium similarity renormalization group theory of dense fermionic systems of chapter 10 and the Green's function approach in chapter 11. We provide extensive code examples and benchmark calculations, allowing thereby an eventual reader to start writing her/his own codes. We start with an object-oriented serial code and end with discussions on strategies for porting the code to present and planned high-performance computing facilities.

   ↳ nucl-thcond-mat.str-elnucl-exLect.Notes Phys.(2017)·8 citations
9. 09*

   The Peak Structure in the In-Flight ${}^3\text{He}(K^{-},\Lambda p)n$ Reaction Around the $\bar{K}NN$ Threshold

   Takayasu Sekihara (JAEA, Ibaraki)🇯🇵 · Eulogio Oset (Valencia U. amd Valencia U., IFIC)🇪🇸 · Angels Ramos (Barcelona U. and ICC, Barcelona U.)🇪🇸

   We theoretically investigate the origin of the peak structure around the $K^{-}pp$ threshold observed in the in-flight ${}^3\text{He}(K^{-},\Lambda p)n$ reaction in the recent E15 experiment at J-PARC. For this purpose, we consider two scenarios to produce the peak. One is that the $\Lambda (1405)$ is generated but it does not correlate with $p$, and the uncorrelated $\Lambda (1405)p$ system subsequently decays into $\Lambda p$. The other one is that the $\bar{K}NN$ bound state is indeed generated and decays into $\Lambda p$. As a result, the experimental signal is qualitatively well reproduced in the $\bar{K}NN$ bound scenario, definitely discarding the uncorrelated $\Lambda (1405)p$ one.

   ↳ nucl-thhep-phnucl-exJPS Conf.Proc.(2017)·2 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.