Fri·Aug 23, 2019Friday·August 23, 2019

1. 01*

   Nuclear Isotope Production by Ordinary Muon Capture Reaction

   I.H. Hashim🇲🇾 · H. Ejiri🇯🇵 · F. Othman🇲🇾 · F. Ibrahim🇲🇾 · F. Soberi🇲🇾 · N.N.A.M.A. Ghani🇲🇾 · T. Shima🇯🇵 · A. Sato🇯🇵 · K. Ninomiya🇯🇵

   Muon capture isotope production (MuCIP) using negative ordinary muon capture reactions (OMC) is used to efficiently produce various kinds of nuclear isotopes for both fundamental and applied science studies. The large capture probability of muon into a nucleus, together with the high intensity muon beam, make it possible to produce nuclear isotopes in the order of 10^{9-10} per second depending on the muon beam intensity. Radioactive isotopes (RIs) produced by MuCIP are complementary to those produced by photon and neutron capture reactions and are used for various science and technology applications. MuCIP on ^{Nat}Mo by using the RCNP MuSIC \muon beam is presented to demonstrate the feasibility of MuCIP. Nuclear isotopes produced by MuCIP are evaluated by using a pre-equilibrium (PEQ) and equilibrium (EQ) proton neutron emission model. Radioactive ${}^{99}$Mo isotopes and the metastable ^{99m}Tc isotopes, which are used extensively in medical science, are produced by MuCIP on ^{Nat}Mo and ^{100}Mo.

   nucl-exhep-exphysics.ins-detNucl.Instrum.Meth.A·8 citations
2. 02*

   Constraining the Sea Quark Distributions Through W${}^{\pm }$ Cross Section Ratio Measurements at STAR

   M. Posik (for the STAR Collaboration)🇺🇸

   Over the past several years, parton distribution functions (PDFs) have become more precise. However there are still kinematic regions where more data are needed to help constrain global PDF extractions, such as the ratio of the sea quark distributions $\bar{d}$/$\bar{u}$ near the valence region. Furthermore, current measurements appear to suggest different high-$x$ behaviors of this ratio. The $W$ cross section ratio ($W^{+}$/$W^{-}$) is sensitive to the unpolarized quark distributions at large $Q^2$ set by the $W$ mass. Such a measurement can be used to help constrain the $\bar{d}$/$\bar{u}$ ratio. The STAR experiment at RHIC is well equipped to measure the leptonic decays of $W$ bosons, in the mid-pseudorapdity range $\left(|\eta |\le 1\right)$, produced in proton-proton collisions at $\sqrt{s}$ = 500/510 GeV. At these kinematics STAR is sensitive to quark distributions near $x$ of 0.16. STAR can also measure $W^{+}$/$W^{-}$ in a more forward region ranging from 1.0 $<\eta <$1.5, which extends the sea quark sensitivity to higher $x$. RHIC runs from 2011 through 2013 have collected about 350 pb${}^{-1}$ of integrated luminosity, and an additional 350 pb${}^{-1}$ from the 2017 run. These proceedings will present preliminary results of the 2011-2013 $W^{+}$/$W^{-}$ cross section ratio measurements. Additionally, the $W/Z$ cross section ratio, differential and total $W$ and $Z$ cross sections are presented.

   nucl-exhep-exPoS(2019)·1 citation
3. 03*

   First-forbidden transitions in the reactor anomaly

   Leendert Hayen🇧🇪 · Joel Kostensalo🇫🇮 · Nathal Severijns🇧🇪 · Jouni Suhonen🇫🇮

   We describe here microscopic calculations performed on the dominant forbidden transitions in reactor antineutrino spectra above 4 MeV using the nuclear shell model. By taking into account Coulomb corrections in the most complete way, we calculate the shape factor with the highest fidelity and show strong deviations from allowed approximations and previously published results. Despite small differences in the ab initio electron cumulative spectra, large differences on the order of several percents are found in the antineutrino spectra. Based on the behaviour of the numerically calculated shape factors we propose a parametrization of forbidden spectra. Using Monte Carlo techniques we derive an estimated spectral correction and uncertainty due to forbidden transitions. We establish the dominance and importance of forbidden transitions in both the reactor anomaly and spectral shoulder analysis. Based on these results, we conclude that a correct treatment of forbidden transitions is indispensable in both the normalization anomaly and spectral shoulder.

   ↳ nucl-thhep-exnucl-exPRC(2019)·102 citations
4. 04*

   Nucleon-antinucleon annihilation at LEAR

   Claude Amsler🇦🇹

   This report is a historical review of the salient results in low energy antiproton-proton and antineutron-proton annihilation obtained at the Low Energy Antiproton Ring (LEAR), which was operated at CERN between 1983 and 1996. The intention is to provide guidelines for future experiments at the CERN AD/ELENA complex and elsewhere. In the spirit of this workshop, hadron spectroscopy - one of the cornerstones at LEAR - is briefly mentioned, while emphasis is put on the annihilation mechanism on one and two nucleons, the final state multiplicity distributions and the contributions from quarks, in particular in annihilation channels involving strangeness.

   ↳ hep-phnucl-exnucl-th17 citations
5. 05*

   First i-TED demonstrator: a Compton imager with Dynamic Electronic Collimation

   V. Babiano🇪🇸 · J. Balibrea🇪🇸 · L. Caballero🇪🇸 · D. Calvo · I. Ladarescu🇪🇸 · J. Lerendegui · S. Mira Prats · C. Domingo-Pardo🇪🇸

   i-TED consists of both a total energy detector and a Compton camera primarily intended for the measurement of neutron capture cross sections by means of the simultaneous combination of neutron time-of-flight (TOF) and $\gamma$-ray imaging techniques. TOF allows one to obtain a neutron-energy differential capture yield, whereas the imaging capability is intended for the discrimination of radiative background sources, that have a spatial origin different from that of the capture sample under investigation. A distinctive feature of i-TED is the embedded Dynamic Electronic Collimation (DEC) concept, which allows for a trade-off between efficiency and image resolution. Here we report on some general design considerations and first performance characterization measurements made with an i-TED demonstrator in order to explore its $\gamma$-ray detection and imaging capabilities.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2020)·22 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.