Thu·Jun 20, 2019Thursday·June 20, 2019

1. 01*

   Observation of the ${}^7$H excited state

   A.A. Bezbakh🇷🇺 · V. Chudoba🇷🇺 · S.A. Krupko🇷🇺 · S.G. Belogurov🇷🇺 · D. Biare🇺🇸 · A.S. Fomichev🇷🇺 · E.M. Gazeeva🇷🇺 · A.V. Gorshkov🇺🇸 · L.V. Grigorenko🇷🇺 · G. Kaminski · O. Kiselev🇩🇪 · D.A. Kostyleva🇩🇪 and 20 other authors

   The ${}^7$H system was populated in the ${}^2$H(${}^8$He,${}^3$He)${}^7$H reaction with a 26 AMeV ${}^8$He beam. The ${}^7$H missing mass energy spectrum, the ${}^3$H energy and angular distributions in the ${}^7$H decay frame were reconstructed. The ${}^7$H missing mass spectrum shows a peak which can be interpreted either as unresolved $5/2^{+}$ and $3/2^{+}$ doublet or one of these states at 6.5(5) MeV. The data also provide indications on the $1/2^{+}$ ground state of ${}^7$H located at 2.0(5) MeV with quite a low population cross section of $\sim 10$ $\mu$b/sr within angular range ${\theta }_{\text{cm}}\simeq 6^{\circ }-30^{\circ }$.

   nucl-exPRL(2020)·19 citations
2. 02*

   Measurement of the total neutron scattering cross section ratios of noble gases of natural isotopic composition using a pulsed neutron beam

   Christopher C. Haddock🇯🇵 · Masayuki Hiromoto · Katsuya Hirota🇯🇵 · Takashi Ino🇯🇵 · Masaaki Kitaguchi🇯🇵 · Kenji Mishima🇯🇵 · Noriko Oi🇯🇵 · Tatsushi Shima🇯🇵 · Hirohiko M. Shimizu🇯🇵 · W. Michael Snow🇺🇸 · Tamaki Yoshioka🇯🇵

   Precision measurements of slow neutron cross sections with atoms have several scientific applications. In particular the n-${}^4$He s-wave scattering length is important to know both for helping to constrain the nuclear three-body interaction and for the proper interpretation of several ongoing slow neutron experiments searching for other types of neutron-atom interactions. We present new measurements of the ratios of the neutron differential scattering cross sections for natural isotopic-abundance mixtures of the noble gases He, Ar, Kr, and Xe to natural isotopic abundance Ne. These measurements were performed using a recently developed neutron scattering apparatus for gas samples located on a pulsed slow neutron beamline which was designed to search for possible exotic neutron-atom interactions and employs both neutron time of flight information and a position-sensitive neutron detector for scattering event reconstruction. We found agreement with the literature values of scattering cross sections inferred from Ar/Ne, Kr/Ne and Xe/Ne differential cross section ratios over the $q$ range of $1-7$ nm${}^{-1}$. However for the case of He/Ne we find that the cross section inferred differs by 11.3% (7.6 $\sigma$) from previously-reported values inferred from neutron phase shift measurements, but is in reasonable agreement with values from other measurements. The very large discrepancy in the He/Ne ratio calls for a new precision measurement of the n-${}^4$He scattering length using neutron interferometry.

   nucl-exPRC(2019)·3 citations
3. 03*

   Texas Active Target (TexAT) detector for experiments with rare isotope beams

   E. Koshchiy🇺🇸 · G.V. Rogachev🇺🇸 · E. Pollacco🇫🇷 · S. Ahn🇺🇸 · E. Uberseder🇺🇸 · J. Hooker🇺🇸 · J. Bishop🇺🇸 · E. Aboud🇺🇸 · M. Barbui🇺🇸 · V.Z. Goldberg🇺🇸 · C. Hunt🇺🇸 · H. Jayatissa🇺🇸 and 5 other authors

   The TexAT (Texas Active Target) detector is a new active-target time projection chamber (TPC) that was built at the Cyclotron Institute Texas A$\&$M University. The detector is designed to be of general use for nuclear structure and nuclear astrophysics experiments with rare isotope beams. TexAT combines a highly segmented Time Projection Chamber (TPC) with two layers of solid state detectors. It provides high efficiency and flexibility for experiments with low intensity exotic beams, allowing for the 3D track reconstruction of the incoming and outgoing particles involved in nuclear reactions and decays.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2020)·48 citations
4. 04*

   Visible narrow cusp structure in ${\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+}$ enhanced by triangle singularity

   Xiao-Hai Liu🇨🇳 · Gang Li🇨🇳 · Ju-Jun Xie🇨🇳 · Qiang Zhao🇨🇳

   A resonance-like structure as narrow as 10 MeV is observed in the $K^{-}p$ invariant mass distributions in ${\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+}$ at Belle. Based on the large data sample of about 1.5 million events and the small bin width of just 1 MeV for the $K^{-}p$ invariant mass spectrum, the narrow peak is found precisely lying at the $\Lambda \eta$ threshold. While lacking evidence for a quark model state with such a narrow width at this mass region, we find that this narrow structure can be naturally identified as a threshold cusp but enhanced by the nearby triangle singularity via the $\Lambda$-$a_0(980{)}^{+}$ or $\eta$-$\Sigma (1660{)}^{+}$ rescatterings.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2019)·35 citations
5. 05*

   Neutron Diffraction Strain Tomography: Demonstration and Proof-of-Concept

   A.W.T. Gregg · J.N. Hendriks · C.M. Wensrich · V.Luzin · A.Wills

   Recently, a number of reconstruction algorithms have been presented for residual strain tomography from Bragg-edge neutron transmission measurements. In this paper, we examine whether strain tomography can also be achieved from diffraction measurements. We outline the proposed method and develop a suitable reconstruction algorithm. This technique is demonstrated in simulation and a proof-of-concept experiment is carried out where the strain field in an axisymmetric sample is reconstructed and validated against conventional diffraction strain scans.

   ↳ physics.comp-phnucl-exRev.Sci.Instrum.(2020)·0 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.