Thu·Sep 3, 2015Thursday·September 3, 2015

1. 01*

   Has been Neutrinoless Double Beta Decay of 130Te observed by the CUORE experiment?

   I.V. Kirpichnikov (Institute for Theoretical and Experimental Physics, Moscow)🇷🇺

   A recent reconsideration of a theoretical process of a neutrinoless double beta decay points out that a signal of the decay should be shifted by a few keV from the Q-value for the 2ß0{\nu}-decay. The conclusion was based on an analysis of the experimental data of the HEIDELBERG-MOSCOW experiment and a reconsideration of the Cuoricino data. Still the recent CUORE results contradicted the conclusions completely. No trace of a 2ß0{\nu}-decay was found and only a limit T1/2 > 2.8*10^24 y was postulated. The problem was very serious and the CUORE results have deserved a more careful consideration.

   nucl-ex1 citation
2. 02*

   Electroexcitation of the ${\Delta }^{+}(1232)$ at low momentum transfer

   A. Blomberg · D. Anez · N. Sparveris · A. Sarty · M. Paolone · S. Gilad · D. Higinbotham · A. R. Abudureyimu · Z. Ahmed · H. Albataineh · K. Allada · B. Anderson and 83 other authors

   We report on new p$(e,e^{\prime }p){\pi }^{\circ }$ measurements at the ${\Delta }^{+}(1232)$ resonance at the low momentum transfer region. The mesonic cloud dynamics is predicted to be dominant and rapidly changing in this kinematic region offering a test bed for chiral effective field theory calculations. The new data explore the low $Q^2$ dependence of the resonant quadrupole amplitudes while extending the measurements of the Coulomb quadrupole amplitude to the lowest momentum transfer ever reached. The results disagree with predictions of constituent quark models and are in reasonable agreement with dynamical calculations that include pion cloud effects, chiral effective field theory and lattice calculations. The reported measurements suggest that improvement is required to the theoretical calculations and provide valuable input that will allow their refinements.

   nucl-exPLB(2016)·22 citations
3. 03*

   Current Status of Nuclear Physics Research

   C.A. Bertulani (Tamu-Commerce)🇺🇸 · M.S. Hussein (USP)🇧🇷

   In this review we discuss the current status of research in nuclear physics which is being carried out in different centers in the World. For this purpose we supply a short account of the development in the area which evolved over the last 9 decades, since the discovery of the neutron. The evolution of the physics of the atomic nucleus went through many stages as more data become available. We briefly discuss models introduced to discern the physics behind the experimental discoveries, such as the shell model, the collective model, the statistical model, the interacting boson model, etc., some of these models may be seemingly in conflict with each other, but this was shown to be only apparent. The richness of the ideas and abundance of theoretical models attests to the important fact that the nucleus is a really singular system in the sense that it evolves from two-body bound states such as the deuteron, to few-body bound states, such as ${}^4$He, ${}^7$Li, ${}^9$Be etc. and up the ladder to heavier bound nuclei containing up to more than 200 nucleons. Clearly statistical mechanics does not work for such finite system, neither does other theories applicable to condensed matter systems. The richness of nuclear physics stems from these restrictions. New theories and models are presently being developed. Theories of the structure and reactions of neutron-rich and proton-rich nuclei, called exotic nuclei, halo nuclei, or Borromean nuclei deal with the wealth of experimental data available in the last 35 years. Further, nuclear astrophysics and stellar and Big Bang nucleosynthesis have become a more mature subject. Due to limited space, this review only covers a few selected topics, mainly those with which the authors have worked with.

   ↳ nucl-thhep-exhep-phnucl-exBraz.J.Phys.(2015)·8 citations
4. 04*

   Proportional electroluminescence in two-phase argon and its relevance to rare-event experiments

   A. Bondar🇷🇺 · A. Buzulutskov🇷🇺 · A. Dolgov🇷🇺 · V. Nosov🇷🇺 · L. Shekhtman🇷🇺 · E. Shemyakina🇷🇺 · A. Sokolov🇷🇺

   Proportional electroluminescence (EL) in gaseous Ar has for the first time been systematically studied in the two-phase mode, at 87 K and 1.00 atm. Liquid argon had a minor (56 ppm) admixture of nitrogen, which allowed to understand, inter alia, the effect of N2 doping on the EL mechanism in rare-event experiments using two-phase Ar detectors. The measurements were performed in a two-phase Cryogenic Avalanche Detector (CRAD) with EL gap located directly above the liquid-gas interface. The EL gap was optically read out in the Vacuum Ultraviolet (VUV), near 128 nm (Ar excimer emission), and in the near Ultraviolet (UV), at 300-450 nm (N2 Second Positive System emission), via cryogenic PMTs and a Geiger-mode APD (GAPD). Proportional electroluminescence was measured to have an amplification parameter of 109+-10 photons per drifting electron per kV overall in the VUV and UV, of which 51+-6% were emitted in the UV. The measured EL threshold, at an electric field of 3.7+-0.2 kV/cm, was in accordance with that predicted by the theory. The latter result is particularly relevant to DarkSide and SCENE dark matter search-related experiments, where the operation electric field was thereby on the verge of appearance of the S2 (ionization-induced) signal. The results obtained pave the way to the development of N2-doped two-phase Ar detectors with enhanced sensitivity to the S2 signal.

   ↳ physics.ins-dethep-exnucl-exEPL(2015)·12 citations
5. 05*

   Astrophysical S factor of {${}^{12}$C($\alpha ,\gamma$)${}^{16}$O} Calculated with the Reduced R-matrix Theory

   Zhen-Dong An🇨🇳 · Zhen-Peng Chen🇨🇳 · Yu-Gang Ma🇨🇳 · Jian-Kai Yu🇨🇳 · Ye-Ying Sun🇨🇳 · Gong-Tao Fan🇨🇳 · Yong-Jiang Li🇨🇳 · Hang-Hua Xu🇨🇳 · Bo-Song Huang🇨🇳 · Kan Wang🇨🇳

   Determination of the accurate astrophysical S factor of {${}^{12}$C($\alpha ,\gamma$)${}^{16}$O} reaction has been regarded as a holy grail of nuclear astrophysics for decades. In current stellar models, a knowledge of that value to better than 10\% is desirable. Due to the practical issues, tremendous experimental and theoretical efforts over nearly 50 years are not able to reach this goal, and the published values contradicted with each other strongly and their uncertainties are 2 times larger than the required precision. To this end we have developed a Reduced R-matrix Theory, based on the classical R-matrix theory of Lane and Thomas, which treats primary transitions to ground state and four bound states as the independent reaction channels in the channel spin representation. With the coordination of covariance statistics and error propagation theory, a global fitting for almost all available experimental data of ${}^{16}$O system has been multi-iteratively analyzed by our powerful code. A reliable, accurate and self-consistent astrophysical S factor of {${}^{12}$C($\alpha ,\gamma$)${}^{16}$O} was obtained with a recommended value $S_{tot}$ (300) = 162.7 $\pm$ 7.3 keV b (4.5\%) which could meet the required precision.

   ↳ nucl-thnucl-exPRC(2015)·21 citations
6. 06*

   Low energy neutron background in deep underground laboratories

   Andreas Best🇮🇹 · Joachim Gorres🇺🇸 · Matthias Junker🇮🇹 · Karl-Ludwig Kratz🇩🇪 · Matthias Laubenstein🇮🇹 · Alexander Long🇺🇸 · Stefano Nisi🇮🇹 · Karl Smith🇺🇸 · Michael Wiescher🇺🇸

   The natural neutron background influences the maximum achievable sensitivity in most deep underground nuclear, astroparticle and double-beta decay physics experiments. Reliable neutron flux numbers are an important ingredient in the design of the shielding of new large-scale experiments as well as in the analysis of experimental data. Using a portable setup of He-3 counters we measured the thermal neutron flux at the Kimballton Underground Research Facility, the Soudan Underground Laboratory, on the 4100 ft and the 4850 ft levels of the Sanford Underground Research Facility, at the Waste Isolation Pilot Plant and at the Gran Sasso National Laboratory. Absolute neutron fluxes at these laboratories are presented.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2016)·78 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.