Fri·Mar 17, 2017Friday·March 17, 2017

1. 01*

   Charm production nearby threshold in pA-interactions at 70 GeV

   A. Afonin🇷🇺 · E. Ardashev🇷🇺 · V. Balandin🇷🇺 · G. Bogdanova🇷🇺 · M. Bogolyubsky · O. Gavrishchuk🇷🇺 · S. Golovnia · S. Gorokhov🇷🇺 · V. Golovkin🇷🇺 · D. Karmanov🇷🇺 · A. Kiryakov🇷🇺 · E. Kokoulina🇷🇺 and 15 other authors

   The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP, Protvino) are presented. Interactions of the 70 GeV proton beam with C, Si and Pb targets were studied to detect decays of charmed $D^0$, ${\overline{D}}^0$, $D^{+}$, $D^{-}$ mesons and ${\Lambda }_c^{+}$ baryon near their production threshold. Measurements of lifetimes and masses are shown a good agreement with PDG data. The inclusive cross sections of charm production and their A-dependencies were obtained. The yields of these particles are compared with the theoretical predictions and the data of other experiments. The measured cross section of the total open charm production (${\sigma }_{\mathrm{tot}}(c\overline{c})$ = 7.1 $\pm$ 2.3(stat) $\pm$1.4(syst) $\mu$b/nucleon) at the collision c.m. energy $\sqrt{s}$ = 11.8 GeV is well above the QCD model predictions. The contributions of different species of charmed particles to the total cross section of the open charm production in proton-nucleus interactions vary with energy.

   nucl-exPoS(2016)·0 citations
2. 02*

   Entrance Channel Effects on the Quasifission Reaction Channel in Cr + W Systems

   K. Hammerton · D. J. Morrissey🇺🇸 · Z. Kohley · D. J. Hinde🇦🇺 · M. Dasgupta🇬🇧 · A. Wakhle · E. Williams🇦🇺 · I. P. Carter · K. J. Cook🇦🇺 · J. Greene · D. Y. Jeung🇦🇺 · D. H. Luong and 5 other authors

   Background: Formation of a fully equilibrated compound nucleus is a critical step in the heavy-ion fusion reaction mechanism but can be hindered by orders of magnitude by quasifission, a process in which the dinuclear system breaks apart prior to full equilibration. To provide a complete description of heavy-ion fusion it is important to characterize the quasifission process. In particular, the impact of changing the neutron-richness of the quasifission process is not well known. A previous study of Cr + W reactions at a constant 13 % above the Coulomb barrier concluded that an increase in neutron-richness leads to a decrease in the prominence of the quasifission reaction channel. Purpose: The interplay between the fusion-fission and quasifission reaction channels, with varying neutron-richness, was explored at a constant excitation energy, closer to the interaction barrier than the previous work, to see if the correlation between neutron-richness and quasifission is valid at lower energies. Methods: Mass distributions were determined for eight different combinations of Cr + W reactions at the Australian National University at 52.0 MeV of excitation energy in the compound nucleus. Results: A curvature parameter was determined for the fission-like fragment mass distributions and compared to various reaction parameters known to influence quasifission. Conclusions: The present work demonstrates that at energies near the interaction barrier the deformation effects dominate over the neutron-richness effects in the competition between quasifission and compound nucleus formation in these Cr + W systems and is an important consideration for future with heavy and superheavy element production reactions.

   nucl-exnucl-thPRC(2019)·12 citations
3. 03*

   $\varphi$ meson mass and decay width in nuclear matter and nuclei

   J.J. Cobos-Martínez🇲🇽 · K. Tsushima🇧🇷 · G. Krein🇧🇷 · A.W.Thomas🇦🇺

   The mass and decay width of the $\varphi$ meson in cold nuclear matter are computed in an effective Lagrangian approach. The medium dependence of these properties are obtained by evaluating kaon-antikaon loop contributions to the $\varphi$ self-energy, employing the medium-modified kaon masses, calculated using the quark-meson coupling model. The loop integral is regularized with a dipole form factor, and the sensitivity of the results to the choice of cutoff mass in the form factor is investigated. At normal nuclear matter density we find a downward shift of the $\varphi$ mass by a few percent, while the decay width is enhanced by an order of magnitude. For a large variation of the cutoff mass parameter, the results for the $\varphi$ mass and the decay width turn out to vary very little. Our results support results in the literature which suggest that one should observe a small downward mass shift and a large broadening of the decay width. In order to explore the possibility of studying the binding and absorption of $\varphi$ mesons in nuclei, we also present the single-particle binding energies and half-widths of $\varphi$-nucleus bound states for some selected nuclei.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2017)·48 citations
4. 04*

   High-quality two-nucleon potentials up to fifth order of the chiral expansion

   D. R. Entem🇪🇸 · R. Machleidt🇺🇸 · Y. Nosyk🇺🇸

   We present NN potentials through five orders of chiral effective field theory ranging from leading order (LO) to next-to-next-to-next-to-next-to-leading order (N4LO). The construction may be perceived as consistent in the sense that the same power counting scheme as well as the same cutoff procedures are applied in all orders. Moreover, the long-range parts of these potentials are fixed by the very accurate pi-N LECs as determined in the Roy-Steiner equations analysis by Hoferichter, Ruiz de Elvira and coworkers. In fact, the uncertainties of these LECs are so small that a variation within the errors leads to effects that are essentially negligible, reducing the error budget of predictions considerably. The NN potentials are fit to the world NN data below pion-production threshold of the year of 2016. The potential of the highest order (N4LO) reproduces the world NN data with the outstanding chi^2/datum of 1.15, which is the highest precision ever accomplished for any chiral NN potential to date. The NN potentials presented may serve as a solid basis for systematic ab initio calculations of nuclear structure and reactions that allow for a comprehensive error analysis. In particular, the consistent order by order development of the potentials will make possible a reliable determination of the truncation error at each order. Our family of potentials is non-local and, generally, of soft character. This feature is reflected in the fact that the predictions for the triton binding energy (from two-body forces only) converges to about 8.1 MeV at the highest orders. This leaves room for three-nucleon-force contributions of moderate size.

   ↳ nucl-thnucl-exPRC(2017)·415 citations
5. 05*

   Project 8 Phase III Design Concept

   A Ashtari Esfahani🇺🇸 · S Böser🇩🇪 · C Claessens🇩🇪 · L de Viveiros🇺🇸 · P J Doe🇺🇸 · S Doeleman🇺🇸 · M Fertl🇺🇸 · E C Finn🇺🇸 · J A Formaggio🇺🇸 · M Guigue🇺🇸 · K M Heeger🇺🇸 · A M Jones🇺🇸 and 18 other authors

   We present a working concept for Phase III of the Project 8 experiment, aiming to achieve a neutrino mass sensitivity of $2\mathrm{eV}$ ($90\%$ C.L.) using a large volume of molecular tritium and a phased antenna array. The detection system is discussed in detail.

   ↳ physics.ins-dethep-exnucl-exJ.Phys.Conf.Ser.(2017)·1 citation
6. 06*

   Results from the Project 8 phase-1 cyclotron radiation emission spectroscopy detector

   A Ashtari Esfahani🇺🇸 · S Böser🇩🇪 · C Claessens🇩🇪 · L de Viveiros🇺🇸 · P J Doe🇺🇸 · S Doeleman🇺🇸 · M Fertl🇺🇸 · E C Finn🇺🇸 · J A Formaggio🇺🇸 · M Guigue🇺🇸 · K M Heeger🇺🇸 · A M Jones🇺🇸 and 18 other authors

   The Project 8 collaboration seeks to measure the absolute neutrino mass scale by means of precision spectroscopy of the beta decay of tritium. Our technique, cyclotron radiation emission spectroscopy, measures the frequency of the radiation emitted by electrons produced by decays in an ambient magnetic field. Because the cyclotron frequency is inversely proportional to the electron's Lorentz factor, this is also a measurement of the electron's energy. In order to demonstrate the viability of this technique, we have assembled and successfully operated a prototype system, which uses a rectangular waveguide to collect the cyclotron radiation from internal conversion electrons emitted from a gaseous ${}^{83m}$Kr source. Here we present the main design aspects of the first phase prototype, which was operated during parts of 2014 and 2015. We will also discuss the procedures used to analyze these data, along with the features which have been observed and the performance achieved to date.

   ↳ physics.ins-dethep-exnucl-exJ.Phys.Conf.Ser.(2017)·1 citation
7. 07*

   Project 8 detector upgrades for a tritium beta decay spectrum using cyclotron radiation

   A Ashtari Esfahani🇺🇸 · S Böser🇩🇪 · C Claessens🇩🇪 · L de Viveiros🇺🇸 · P J Doe🇺🇸 · S Doeleman🇺🇸 · M Fertl🇺🇸 · E C Finn🇺🇸 · J A Formaggio🇺🇸 · M Guigue🇺🇸 · K M Heeger🇺🇸 · A M Jones🇺🇸 and 18 other authors

   Following the successful observation of single conversion electrons from ${}^{83m}$Kr using Cyclotron Radiation Emission Spectroscopy (CRES), Project 8 is now advancing its focus toward a tritium beta decay spectrum. A tritium spectrum will be an important next step toward a direct measurement of the neutrino mass for Project 8. Here we discuss recent progress on the development and commissioning of a new gas cell for use with tritium, and outline the primary goals of the experiment for the near future.

   ↳ physics.ins-dethep-exnucl-ex1 citation

* 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.