Nuclear Experiment·nucl-ex
11 papers—6 primary·5 cross-listed·reconstructed*
The 2017 update of the discovery of nuclide project is presented. 34 new nuclides were observed for the first time in 2017. However, the assignment of six previously identified nuclides had to be retracted.
A. Papageorgiou🇬🇷 · G.A. Souliotis🇬🇷 · K. Tshoo🇰🇷 · S.C. Jeong🇰🇷 · B.H. Kang🇰🇷 · Y.K. Kwon🇰🇷 · M. Veselsky🇸🇰 · S.J. Yennello🇺🇸 · A. Bonasera🇺🇸
We studied the production of neutron-rich nuclides in multinucleon transfer collisions of stable and radioactive beams in the mass range A=40-60. We first presented our experimental cross section data of projectile fragments from the reaction of 40Ar(15 MeV/nucleon) with 64Ni, 58Ni and 27Al. We then compared them with calculations based on either the deep-inelastic transfer (DIT) model or the constrained molecular dynamics (CoMD) model, followed by the statistical multifragmentation model (SMM). An overall good agreement of the calculations with the experimental data is obtained. We continued with calculations of the reaction of 40Ar (15 MeV/nucleon) with 238U target and then with reactions of 48Ca (15 MeV/nucleon) with 64Ni and 238U targets. In these reactions, neutron-rich rare isotopes with large cross sections are produced. These nuclides, in turn, can be assumed to form radioactive beams and interact with a subsequent target (preferably 238U), leading to the production of extremely neutron-rich and even new isotopes (e.g. 60Ca) in this mass range. We conclude that multinucleon transfer reactions with stable or radioactive beams at the energy of around 15 MeV/nucleon offer an effective route to access extremely neutron-rich rare isotopes for nuclear structure or reaction studies.
Niseem Magdy (For the STAR Collaboration)🇺🇸
New measurements of rapidity-even dipolar flow, v, are presented for several transverse momenta, , and centrality intervals in Au+Au collisions at and GeV, U+U collisions at GeV, and Cu+Au, Cu+Cu, d+Au and p+Au collisions at ~GeV. The v shows characteristic dependencies on , centrality, collision system and , consistent with the expectation from a hydrodynamic-like expansion to the dipolar fluctuation in the initial state. These measurements could serve as constraints to distinguish between different initial-state models, and aid a more reliable extraction of the specific viscosity .
M. Alotiby · I. Greguric · T. Kibédi🇦🇺 · B.Q. Lee · M. Roberts · A.E. Stuchbery🇦🇺 · Pi Tee · T. Tornyi🇳🇴 · M. Vos
Auger electrons emitted after nuclear decay have potential application in targeted cancer therapy. For this purpose it is important to know the Auger electron yield per nuclear decay. In this work we describe a measurement of the ratio of the number of conversion electrons (emitted as part of the nuclear decay process) to the number of Auger electrons (emitted as part of the atomic relaxation process after the nuclear decay) for the case of I. Results are compared with Monte-Carlo type simulations of the relaxation cascade using the BrIccEmis code. Our results indicate that for I the calculations based on rates from the Evaluated Atomic Data Library (EADL) underestimate the K Auger yields by 20\%.
F. Ferraro🇮🇹 · M.P. Takács🇩🇪 · D. Piatti🇮🇹 · V. Mossa🇮🇹 · M. Aliotta🇬🇧 · D. Bemmerer🇩🇪 · A. Best🇮🇹 · A. Boeltzig🇮🇹 · C. Broggini🇮🇹 · C.G. Bruno🇬🇧 · A. Caciolli🇮🇹 · F. Cavanna🇮🇹 and 33 other authors
The experimental study of nuclear reactions of astrophysical interest is greatly facilitated by a low-background, high-luminosity setup. The Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator offers ultra-low cosmic-ray induced background due to its location deep underground in the Gran Sasso National Laboratory (INFN-LNGS), Italy, and high intensity, 250-500 A, proton and ion beams. In order to fully exploit these features, a high-purity, recirculating gas target system for isotopically enriched gases is coupled to a high-efficiency, six-fold optically segmented bismuth germanate (BGO) -ray detector. The beam intensity is measured with a beam calorimeter with constant temperature gradient. Pressure and temperature measurements have been carried out at several positions along the beam path, and the resultant gas density profile has been determined. Calibrated -intensity standards and the well-known = 278 keV resonance were used to determine the -ray detection efficiency and to validate the simulation of the target and detector setup. As an example, the recently measured resonance at = 189.5 keV in the Ne(p,)Na reaction has been investigated with high statistics, and the -decay branching ratios of the resonance have been determined.
C. Schmitt🇫🇷 · K.-H. Schmidt🇫🇷 · B. Jurado🇫🇷
The GEneral description of Fission observables (GEF) model was developed to produce fission related nuclear data which are of crucial importance for basic and applied nuclear physics. The investigation of the performance of the GEF code is here extended to a region in fissioning-system mass, charge, excitation energy and angular momentum, as well as to new observables, that could not be benchmarked in detail so far. The work focuses on fragment mass and isotopic distributions, benefiting from recent innovative measurements. The approach reveals a high degree of consistency and provides a very reasonable description of the new data. The physics behind specific discrepancies is discussed, and hints to improve on are given. Comparison of the calculation with experiment permits to highlight the influence of the system intrinsic properties, their interplay, and the importance of experimental aspects, namely instrumental resolution. All together points to the necessity of as selective and accurate as possible experimental data, for proper unfolding of the different influences and robust interpretation of the measurement. The GEF code has become a widely used tool for this purpose
Hao Qiao🇨🇳 · Chunyu Lu🇨🇳 · Xun Chen🇨🇳 · Ke Han🇨🇳 · Xiangdong Ji🇨🇳 · Siguang Wang🇨🇳
The PandaX-III experiment will search for neutrinoless double beta decay of Xe with high pressure gaseous time projection chambers at the China Jin-Ping underground Laboratory. The tracking feature of gaseous detectors helps suppress the background level, resulting in the improvement of the detection sensitivity. We study a method based on the convolutional neural networks to discriminate double beta decay signals against the background from high energy gammas generated by Bi and Tl decays based on detailed Monte Carlo simulation. Using the 2-dimensional projections of recorded tracks on two planes, the method successfully suppresses the background level by a factor larger than 100 with a high signal efficiency. An improvement of on the efficiency ratio of is achieved in comparison with the baseline in the PandaX-III conceptual design report.
R. Imai · T. Tada · M. Kimura🇯🇵
A new theoretical method is proposed to describe the ground and excited cluster states of atomic nuclei. The method utilizes the equation-of-motion of the Gaussian wave packets to generate the basis wave functions having various cluster configurations. The generated basis wave functions are superposed to diagonalize the Hamiltonian. In other words, this method uses the real time as the generator coordinate. The application to the system as a benchmark shows that the new method works efficiently and yields the result consistent with or better than the other cluster models. Brief discussion on the structure of the excited and states is also made.
M. Arenz🇩🇪 · W.-J. Baek🇩🇪 · M. Beck🇩🇪 · A. Beglarian🇩🇪 · J. Behrens🇩🇪 · T. Bergmann🇩🇪 · A. Berlev🇷🇺 · U. Besserer🇩🇪 · K. Blaum🇩🇪 · T. Bode🇩🇪 · B. Bornschein🇩🇪 · L. Bornschein🇩🇪 and 117 other authors
The Karlsruhe Tritium Neutrino (KATRIN) experiment is a large-scale effort to probe the absolute neutrino mass scale with a sensitivity of 0.2 eV (90% confidence level), via a precise measurement of the endpoint spectrum of tritium beta decay. This work documents several KATRIN commissioning milestones: the complete assembly of the experimental beamline, the successful transmission of electrons from three sources through the beamline to the primary detector, and tests of ion transport and retention. In the First Light commissioning campaign of Autumn 2016, photoelectrons were generated at the rear wall and ions were created by a dedicated ion source attached to the rear section; in July 2017, gaseous Kr-83m was injected into the KATRIN source section, and a condensed Kr-83m source was deployed in the transport section. In this paper we describe the technical details of the apparatus and the configuration for each measurement, and give first results on source and system performance. We have successfully achieved transmission from all four sources, established system stability, and characterized many aspects of the apparatus.
Bolometers are cryogenic calorimeters which feature excellent energy resolution, low energy threshold, high detection efficiency, flexibility in choice of materials, particle identification capability if operated as hybrid devices. After thirty years of rapid progresses, they represent nowadays a leading technology in several fields: particle and nuclear physics, X-ray astrophysics, cosmology. However, further and substantial developments are required to increase the sensitivity to the levels envisioned by future researches. A review of the challenges to be addressed and potentialities of bolometers in the search for rare nuclear decays is given, with particular emphasis to the neutrinoless double beta decay physics case.
Peng Chen🇨🇳 · Salvador Centelles Chuliá🇪🇸 · Gui-Jun Ding🇨🇳 · Rahul Srivastava🇪🇸 · José W. F. Valle🇪🇸
We study the implications of generalized CP transformations acting on the mass matrices of charged leptons in a model-independent way. Generalized , and symmetries are considered in detail. In all cases the physical parameters of the lepton mixing matrix, three mixing angles and three CP phases can be expressed in terms of a restricted set of independent "theory" parameters that characterize a given choice of CP transformation. This leads to implications for neutrino oscillations as well as neutrinoless double beta decay experiments.
* 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.