Nuclear Experiment·nucl-ex
5 papers—3 primary·2 cross-listed·reconstructed*
The 2014 update of the discovery of nuclide project is presented. Only six new nuclides were observed for the first time in 2014 while the assignments of seventeen other nuclides were revised. In addition, for another fourteen nuclides the laboratories where they were discovered were reassigned.
Azimuthal angle dependence of the pion source radii was measured applying the event shape selection at the PHENIX experiment. The measured final source eccentricity is found to be enhanced when selecting events with higher magnitude of the second-order flow vector, as well as the elliptic flow coefficient . The spatial twist of the particle-emitting source was also explored using a transport model. Results indicate a possible twisted source in the final state due to the initial longitudinal fluctuations.
A. Esser🇩🇪 · S. Nagao🇯🇵 · F. Schulz🇩🇪 · P. Achenbach🇩🇪 · C. Ayerbe Gayoso🇩🇪 · R. Böhm🇩🇪 · O. Borodina🇩🇪 · D. Bosnar🇭🇷 · V. Bozkurt🇩🇪 · L. Debenjak🇸🇮 · M. O. Distler🇩🇪 · I. Friščić🇭🇷 and 29 other authors
At the Mainz Microtron MAMI, the first high-resolution pion spectroscopy from decays of strange systems was performed by electron scattering off a Be-9 target in order to study the ground-state masses of Lambda-hypernuclei. Positively charged kaons were detected by a short-orbit spectrometer with a broad momentum acceptance at zero degree forward angles with respect to the beam, efficiently tagging the production of strangeness in the target nucleus. In coincidence, negatively charged decay-pions were detected by two independent high-resolution spectrometers. About 10^3 pionic weak decays of hyperfragments and hyperons were observed. The pion momentum distribution shows a monochromatic peak at p_pi ~ 133 MeV/c, corresponding to the unique signature for the two-body decay of hyperhydrogen Lambda H-4 -> He-4 + pi-, stopped inside the target. Its binding energy was determined to be B_Lambda = 2.12 +- 0.01 (stat.) +- 0.09 (syst.) MeV with respect to the H-3 + Lambda mass.
With discovery of the Higgs boson, the Standard Model of Particle Physics became complete. Its formulation is a remarkable story; and the process of verification is continuing, with the most important chapter being the least well understood. Quantum Chromodynamics (QCD) is that part of the Standard Model which is supposed to describe all of nuclear physics and yet, almost fifty years after the discovery of quarks, we are only just beginning to understand how QCD moulds the basic bricks for nuclei: pious, neutrons, protons. QCD is characterized by two emergent phenomena: confinement and dynamical chiral symmetry breaking (DCSB), whose implications are extraordinary. This contribution describes how DCSB, not the Higgs boson, generates more than 98% of the visible mass in the Universe, explains why confinement guarantees that condensates, those quantities that were commonly viewed as constant mass-scales that fill all spacetime, are instead wholly contained within hadrons, and elucidates a range of observable consequences of confinement and DCSB whose measurement is the focus of a vast international experimental programme.
Raj Kumar · J. A. Lay🇪🇸 · A. Vitturi🇮🇹
: Nuclear fusion has been shown to be a perfect probe to study the different nuclear shapes. However, the possibility of testing octupole deformation of a nucleus with this tool has not been fully explored yet. The presence of a stactic octupole deformation in nuclei will enhanced a possible permanent electric dipole moment, leading to a possible demonstration of parity violation. : To check whether static octupole deformation or octupole vibration in fusion give qualitatively different results so that both situations can be experimentally disentangled. : Fusion cross sections are computed in the Coupled-Channels formalism making use of the Ingoing-Wave Boundary Conditions (IWBC) for the systems O+Ba and O+Ra. : Barrier distributions of the two considered schemes show different patterns. For the Ra case, the octupole deformation parameter is large enough to create a sizeable difference. : The measurement of barrier distributions can be an excellent probe to clarify the presence of octupole deformation.
* 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.