Mon·Dec 11, 2017Monday·December 11, 2017

1. 01*

   A Search for deviations from the inverse square law of gravity at nm range using a pulsed neutron beam

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

   We describe an experimental search for deviations from the inverse square law of gravity at the nanometer length scale using neutron scattering from noble gases on a pulsed slow neutron beamline. By measuring the neutron momentum transfer ($q$) dependence of the differential cross section for xenon and helium and comparing to their well-known analytical forms, we place an upper bound on the strength of a new interaction as a function of interaction length $\lambda$ which improves upon previous results in the region $\lambda <0.1$nm, and remains competitive in the larger $\lambda$ region. A pseudoexperimental simulation developed for this experiment and its role in the data analysis described. We conclude with plans for improving sensitivity in the larger $\lambda$ region.

   nucl-exhep-exphysics.ins-detPRD(2018)·48 citations
2. 02*

   Exclusive Backward-Angle Omega Meson Electroproduction

   Wenliang Li🇨🇦

   This work is a pioneering study of backward-angle omega cross sections through the exclusive 1H(e,e'p)omega reaction using the missing mass reconstruction technique. The extracted cross sections are separated into the transverse (T), longitudinal (L), and LT, TT interference terms. The analyzed data were part of experiment E01-004 (Fpi-2), which used 2.6-5.2GeV electron beams and HMS+SOS spectrometers in Jefferson Lab Hall C. The primary objective was to detect coincidence pion in the forward-angle, where the backward-angle omega events were fortuitously detected. The experiment has central Q2 values of 1.60 and 2.45GeV2, at W=2.21GeV. There was significant coverage in phi and epsilon, which allowed separation of sigma_T,L,LT,TT. The data set has a unique u coverage of -u~0, which corresponds to -t>4GeV2. The separated sigma_T result suggest a flat ~1/Q^(1.33+/-1.21) dependence, whereas sigma_L seems to hold a stronger 1/Q^(9.43+/-6.28) dependence. The sigma_L/sigma_T ratio indicate sigma_T dominance at Q2=2.45 GeV2 at the ~90% confidence level. After translating the results into the -t space of the published CLAS data, our data show evidence of a backward-angle omega electroproduction peak at both Q2 settings. Previously, this phenomenon showing both forward and backward-angle peaks was only observed in the meson photoproduction data. Through comparison of our sigma_T data with the prediction of the Transition Distribution Amplitude (TDA) model, and signs of sigma_T dominance, promising indications of the applicability of the TDA factorization are demonstrated at a much lower Q2 value than its preferred range of Q2>10GeV2. These studies have opened a new means to study the transition of the nucleon wavefunction through backward-angle experimental observables.

   nucl-ex7 citations
3. 03*

   Rapid change of multiplicity fluctuations in system size dependence at SPS energies

   Andrey Seryakov (for the NA61/SHINE collaboration)🇷🇺

   Recent preliminary results on multiplicity fluctuations in p+p, Be+Be and Ar+Sc collisions from the NA61/SHINE collaboration are presented. The scaled variance of charged hadron multiplicity changes little when going from p+p to Be+Be collisions and drops dramatically from Be+Be to Ar+Sc interactions. The centrality selection procedure and the influence of volume fluctuations are discussed. Comparisons with the EPOS event generator are shown.

   ↳ hep-exnucl-exKnE Energ.Phys.(2018)·4 citations
4. 04*

   Effect of channel coupling on the elastic scattering of lithium isotopes

   T. Furumoto🇯🇵 · T. Suhara🇯🇵 · N. Itagaki🇯🇵

   Herein, we investigated the channel coupling (CC) effect on the elastic scatterings of lithium (Li) isotopes ($A=$ 6--9) for the ${}^{12}$C and ${}^{28}$Si targets at $E/A=$ 50--60 MeV. The wave functions of the Li isotopes were obtained using the stochastic multi-configuration mixing (SMCM) method based on the microscopic-cluster model. The proton radii of the ${}^7$Li, ${}^8$Li, and ${}^9$Li nuclei became smaller as the number of valence neutrons increased. The valence neutrons in the ${}^8$Li and ${}^9$Li nuclei exhibited a glue-like behavior, thereby attracting the $\alpha$ and $t$ clusters. Based on the transition densities derived from these microscopic wave functions, the elastic-scattering cross section was calculated using a microscopic coupled-channel (MCC) method with a complex $G$-matrix interaction. The existing experimental data for the elastic scatterings of the Li isotopes and ${}^{10}$Be nuclei were well reproduced. The Li isotope elastic cross sections were demonstrated for the ${}^{12}$C and ${}^{28}$Si targets at $E/A$ =53 MeV. The glue-like effect of the valence neutrons on the Li isotope was clearly demonstrated by the CC effect on elastic scattering. Finally, we realize that the valence neutrons stabilized the bindings of the core parts and the CC effect related to core excitation was indeed reduced.

   ↳ nucl-thnucl-exPRC(2018)·18 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.