Nuclear Experiment·nucl-ex
4 papers—1 primary·3 cross-listed·reconstructed*
The Jefferson Lab facilities have undergone a substantial upgrade, both of accelerator, CEBAF, and of the experimental installations. We will discuss the progress to completion of these facilities, the status of accelerator commissioning, and the recent first operations for physics. We will then flesh out the anticipated exciting physics program of the next several years.
J. Berges🇩🇪 · K. Reygers🇩🇪 · N. Tanji🇩🇪 · R. Venugopalan🇺🇸
Recent classical-statistical numerical simulations have established the "bottom-up" thermalization scenario of Baier et al. as the correct weak coupling effective theory for thermalization in ultrarelativistic heavy-ion collisions. We perform a parametric study of photon production in the various stages of this bottom-up framework to ascertain the relative contribution of the off-equilibrium "Glasma" relative to that of a thermalized Quark-Gluon Plasma. Taking into account the constraints imposed by the measured charged hadron multiplicities at RHIC and the LHC, we find that Glasma contributions are important especially for large values of the saturation scale at both energies. These non-equilibrium effects should therefore be taken into account in studies where weak coupling methods are employed to compute photon yields.
B. Collett🇺🇸 · F. Bateman🇺🇸 · W. K. Bauder🇺🇸 · J. Byrne🇬🇧 · W. A. Byron🇺🇸 · W. Chen🇨🇦 · G. Darius🇺🇸 · C. DeAngelis🇺🇸 · M. S. Dewey🇺🇸 · T. R. Gentile🇺🇸 · M. T. Hassan🇺🇸 · G. L. Jones🇺🇸 and 12 other authors
We describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. The apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. Details of the method, apparatus, detectors, data acquisition, and data reduction scheme are presented, along with a discussion of the important systematic effects.
Zach Meisel🇺🇸 · M. T. Moran🇺🇸 · G. Gilardy🇺🇸 · J. Schmitt🇺🇸 · C. Seymour🇺🇸 · M. Couder🇺🇸
Radiative alpha-capture, (), reactions play a critical role in nucleosynthesis and nuclear energy generation in a variety of astrophysical environments. The St. George recoil separator at the University of Notre Dame's Nuclear Science Laboratory was developed to measure () reactions in inverse kinematics via recoil detection in order to obtain nuclear reaction cross sections at the low energies of astrophysical interest, while avoiding the -background that plagues traditional measurement techniques. Due to the -ray produced by the nuclear reaction at the target location, recoil nuclei are produced with a variety of energies and angles, all of which must be accepted by St. George in order to accurately determine the reaction cross section. We demonstrate the energy acceptance of the St. George recoil separator using primary beams of helium, hydrogen, neon, and oxygen, spanning the magnetic and electric rigidity phase space populated by recoils of anticipated () reaction measurements. We found the performance of St. George meets the design specifications, demonstrating its suitability for () reaction measurements of astrophysical interest.
* 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.