Mon·Jul 2, 2018Monday·July 2, 2018

1. 01*

   Proton Form Factor Ratio, ${\mu }_p{G}_E^p/G_M^p$ from Double Spin Asymmetry

   A. Liyanage🇺🇸 · W. Armstrong🇺🇸 · H. Kang🇰🇷 · J. Maxwell🇺🇸 · J. Mulholland🇺🇸 · L. Ndukum🇺🇸 · A. Ahmidouch🇺🇸 · I. Albayrak🇺🇸 · A. Asaturyan🇦🇲 · O. Ates🇺🇸 · H. Baghdasaryan🇺🇸 · W. Boeglin🇺🇸 and 88 other authors

   The ratio of the electric and magnetic form factor of the proton, ${\mu }_p{G}_E^p/G_M^p$, has been measured for elastic electron-proton scattering with polarized beam and target up to four-momentum transfer squared, $Q^2=5.66$ (GeV/c)${}^2$ using the double spin asymmetry for target spin orientation aligned nearly perpendicular to the beam momentum direction. This measurement of ${\mu }_p{G}_E^p/G_M^p$ agrees with the $Q^2$ dependence of previous recoil polarization data and reconfirms the discrepancy at high $Q^2$ between the Rosenbluth and the polarization-transfer method with a different measurement technique and systematic uncertainties uncorrelated to those of the recoil-polarization measurements. The form factor ratio at $Q^2$=2.06 (GeV/c)${}^2$ has been measured as ${\mu }_p{G}_E^p/G_M^p=0.720\pm 0.176_{stat}\pm 0.039_{sys}$, which is in agreement with an earlier measurement with the polarized target technique at similar kinematics. The form factor ratio at $Q^2$=5.66 (GeV/c)${}^2$ has been determined as ${\mu }_p{G}_E^p/G_M^p=0.244\pm 0.353_{stat}\pm 0.013_{sys}$, which represents the highest $Q^2$ reach with the double spin asymmetry with polarized target to date.

   nucl-exPRC(2020)·15 citations
2. 02*

   The Masses of the $T_z=-3/2$ Nuclei ${}^{27}$P and ${}^{29}$S

   C. Y. Fu🇨🇳 · Y. H. Zhang🇨🇳 · X. H. Zhou🇨🇳 · M. Wang🇨🇳 · Yu. A. Litvinov🇩🇪 · K. Blaum🇩🇪 · H. S. Xu🇨🇳 · X. Xu🇨🇳 · P. Shuai🇨🇳 · Y. H. Lam🇨🇳 · R. J. Chen🇨🇳 · X. L. Yan🇨🇳 and 24 other authors

   Isochronous mass spectrometry has been applied in the storage ring CSRe to measure the masses of the $T_z=-3/2$ nuclei ${}^{27}$P and ${}^{29}$S. The new mass excess value $ME$(${}^{29}$S) $=-3094(13)$~keV is 66(52)~keV larger than the result of the previous ${}^{32}$S(${}^3$He,${}^6$He)${}^{29}$S reaction measurement in 1973 and a factor of 3.8 more precise. The new result for ${}^{29}$S, together with those of the $T=3/2$ isobaric analog states (IAS) in ${}^{29}$P, ${}^{29}$Si, and ${}^{29}$Al, fit well into the quadratic form of the Isobaric Multiplet Mass Equation IMME. The mass excess of ${}^{27}$P has been remeasured to be $ME{(}^{27}$P$)=-685(42)$ keV. By analyzing the linear and quadratic coefficients of the IMME in the $T_z=-3/2$ $sd$-shell nuclei, it was found that the ratio of the Coulomb radius parameters is $R\approx 0.96$ and is nearly the same for all $T=3/2$ isospin multiplets. Such a nearly constant $R$-value, apparently valid for the entire light mass region with $A>9$, can be used to set stringent constraints on the isovector and isotensor components of the isospin non-conserving forces in theoretical calculations.

   nucl-exPRC(2018)·17 citations
3. 03*

   Effect of beam energy straggling on resonant yield in thin gas targets: The cases ${}^{22}$Ne(p,{\gamma})${}^{23}$Na and ${}^{14}$N(p,{\gamma})${}^{15}$O

   D. Bemmerer🇩🇪 · F. Cavanna🇮🇹 · R. Depalo🇮🇹 · M. Aliotta🇬🇧 · M. Anders🇩🇪 · A. Boeltzig🇮🇹 · C. Broggini🇮🇹 · C. Bruno🇬🇧 · A. Caciolli🇮🇹 · P. Corvisiero🇮🇹 · T. Davinson🇬🇧 · Z. Elekes🇭🇺 and 16 other authors

   When deriving resonance strengths using the thick-target yield approximation, for very narrow resonances it may be necessary to take beam energy straggling into account. This applies to gas targets of a few keV width, especially if there is some additional structure in target stoichiometry or detection efficiency. The correction for this effect is shown and tested on recent studies of narrow resonances in the ${}^{22}$Ne(p,{\gamma})${}^{23}$Na and ${}^{14}$N(p,{\gamma})${}^{15}$O reactions.

   nucl-exEPL(2018)·19 citations
4. 04*

   Novel approach to excitation spectrum from correlated ground state

   Takaharu Otsuka🇯🇵 · Tomoaki Togashi🇯🇵 · Noritaka Shimizu🇯🇵 · Yutaka Utsuno🇯🇵 · Toshio Suzuki🇯🇵

   A novel approach to obtain the excitation spectrum of nuclei is presented as well as its proof-of-principle. The Monte Carlo Shell Model is extended so that the excitation spectrum can be calculated from its ground state with full of correlations. This new methodology is sketched with the example of E1 excitations from the nucleus 88Sr in comparison to experiment. From the B(E1; 0+1 -> 1- ) value, the photoabsorption cross section is calculated, with the Giant Dipole and Pygmy Dipole Resonances in agreement with experiment. Applications to 90Sr and 90,93Zr are shown with similar characteristics. The possible relevance to the transmutation of long-lived fission products is discussed

   ↳ nucl-thnucl-ex1 citation
5. 05*

   Quantitative analysis of tensor effects in the relativistic Hartree-Fock theory

   Zhiheng Wang🇨🇳 · Qiang Zhao🇨🇳 · Haozhao Liang🇯🇵 · Wen Hui Long🇨🇳

   Tensor force is identified in each meson-nucleon coupling in the relativistic Hartree-Fock theory. It is found that all the meson-nucleon couplings, except the $\sigma$-scalar one, give rise to the tensor force. The effects of tensor force on various nuclear properties can now be investigated quantitatively, which allows fair and direct comparisons with the corresponding results in the non-relativistic framework. The tensor effects on nuclear binding energies and the evolutions of the $Z,N=8,20$, and $28$ magic gaps are studied. The tensor contributions to the binding energies are shown to be tiny in general. The $Z,N=8$ and $20$ gaps are sensitive to the tensor force, but the $Z,N=28$ gaps are not.

   ↳ nucl-thnucl-exPRC(2018)·34 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.