Thu·Jul 27, 2017Thursday·July 27, 2017

1. 01*

   Muon capture reaction on ${}^{100}Mo$ to study nuclear responses for double beta decays and astro-neutrinos

   I.H. Hashim · H. Ejiri · T. Shima · A. Sato · Y. Kuno · N. Kawamura · S. Miyake · K. Ninomiya

   The negative-muon capture reaction (MCR) on the enriched ${}^{100}Mo$ isotope was studied for the first time to investigate neutrino nuclear response for neutrino-less double beta decays and supernova neutrino nuclear interactions. MCR on ${}^{100}Mo$ proceeds mainly as ${}^{100}Mo(mu,xn{)}^{100-x}Nb$ with $x$ being the number of neutrons emitted from MCR. The Nb isotope mass distribution was obtained by measuring delayed gamma-rays from radioactive ${}^{100-x}Nb$. By using the neutron emission model after MCR, the neutrino response (the strength distribution) for MCR was derived. Giant resonance (GR)-like distribution at the peak energy around 11-14 MeV, suggests concentration of the MCR strength at the muon capture GR region.

   nucl-exnucl-thPRC(2018)·41 citations
2. 02*

   Slotted Rotatable Target Assembly Used In a Search for Possible Long Range Spin Dependent Interactions From Vector Boson Exchange Using Polarized Slow Neutrons

   Christopher Haddock · Bret Crawford · Walter Fox · Ian Francis · Adam Holley · Murad Sarsour · W. Michael Snow · John Vanderwerp

   We discuss the design and construction of a novel target array of nonmagnetic test masses used in a neutron polarimetry measurement made in search for new possible exotic spin dependent neutron-atom interactions of Nature at sub\,-$mm$ length scales. This target was designed to accept and efficiently transmit a transversely polarized slow neutron beam through a series of long open parallel slots bounded by flat rectangular plates. These openings possessed equal atom density gradients across the slots from the flat test masses with dimensions optimized to achieve maximum sensitivity to an exotic spin-dependent interaction from vector boson exchanges with ranges in the millimeter to micron regime. The parallel slots were oriented differently in four quadrants that can be rotated about the neutron beam axis using a Geneva drive. The spin rotation signals from the 4 quadrants were measured using a segmented neutron ion chamber in parallel to suppress possible systematic errors from stray magnetic fields in the target region. Design constraints and systematic effects are discussed.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2018)·1 citation
3. 03*

   Constraining the equation of state with identified particle spectra

   Akihiko Monnai🇫🇷 · Jean-Yves Ollitrault🇫🇷

   We show that in a central nucleus-nucleus collision, the variation of the mean transverse mass with the multiplicity is determined, up to a rescaling, by the variation of the energy over entropy ratio as a function of the entropy density, thus providing a direct link between experimental data and the equation of state. Each colliding energy thus probes the equation of state at an effective entropy density, whose approximate value is $19$ fm${}^{-3}$ for Au+Au collisions at 200 GeV and $41$ fm${}^{-3}$ for Pb+Pb collisions at 2.76 TeV, corresponding to temperatures of $227$ MeV and $279$ MeV if the equation of state is taken from lattice calculations. The relative change of the mean transverse mass as a function of the colliding energy gives a direct measure of the pressure over energy density ratio $P/ϵ$, at the corresponding effective density. Using RHIC and LHC data, we obtain $P/ϵ=0.21\pm 0.10$, in agreement with the lattice value $P/ϵ=0.23$ in the corresponding temperature range. Measurements over a wide range of colliding energies using a single detector with good particle identification would help reducing the error.

   ↳ nucl-thhep-lathep-phnucl-exPRC(2017)·17 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.