Tue·Nov 7, 2017Tuesday·November 7, 2017

1. 01*

   Probing electron-argon scattering for liquid-argon based neutrino-oscillation program

   V. Pandey🇺🇸 · D. Abrams🇺🇸 · S. Alsalmi🇺🇸 · A. M. Ankowski🇺🇸 · J. Bane🇺🇸 · O. Benhar🇮🇹 · H. Dai🇺🇸 · D. B. Day🇺🇸 · D. W. Higinbotham🇺🇸 · C. Mariani🇺🇸 · M. Murphy🇺🇸 · D. Nguyen🇺🇸

   The electron scattering has been a vital tool to study the properties of the target nucleus for over five decades. Though, the particular interest on ${}^{40}$Ar nucleus stemmed from the progress in the accelerator-based neutrino-oscillation experiments. The complexity of nuclei comprising the detectors and their weak response turned out to be one of the major hurdles in the quest of achieving unprecedented precision in these experiments. The challenges are further magnified by the use of Liquid Argon Time Projection Chambers (LArTPCs) in the short- (SBN) and long-baseline (DUNE) neutrino program, with almost non-existence electron-argon scattering data and hence with no empirical basis to test and develop nuclear models for ${}^{40}$Ar. In light of these challenges, an electron-argon experiment, E12-14-012, was proposed at Jefferson Lab. The experiment has recently successfully completed collecting data for $(e,e^{\prime }p)$ and $(e,e^{\prime })$ processes, not just on ${}^{40}$Ar but also on ${}^{48}$Ti, and ${}^{12}$C targets. While the analysis is running with full steam, in this contribution, we present a brief overview of the experiment.

   nucl-exhep-exnucl-thphysics.ins-det3 citations
2. 02*

   Measurement of the Q^2 Dependence of the Deuteron Spin Structure Function g_1 and its Moments at Low Q^2 with CLAS

   K.P. Adhikari🇺🇸 · A. Deur🇺🇸 · L. El Fassi🇺🇸 · H. Kang🇰🇷 · S.E. Kuhn🇺🇸 · M. Ripani🇮🇹 · K. Slifer🇺🇸 · X. Zheng🇺🇸 · S. Adhikari🇺🇸 · Z. Akbar🇺🇸 · M.J. Amaryan🇺🇸 · H. Avakian🇺🇸 and 136 other authors

   We measured the $g_1$ spin structure function of the deuteron at low $Q^2$, where QCD can be approximated with chiral perturbation theory ($\chi$PT). The data cover the resonance region, up to an invariant mass of $W\approx 1.9$~GeV. The generalized Gerasimov-Drell-Hearn sum, the moment ${\bar{\Gamma }}_1^d$ and the integral ${\bar{I}}_{\gamma }^d$ related to the spin polarizability ${\gamma }_0^d$ are precisely determined down to a minimum $Q^2$ of 0.02~GeV${}^2$ for the first time, about 2.5 times lower than that of previous data. We compare them to several $\chi$PT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the $\chi$PT domain.

   nucl-exPRL(2018)·40 citations
3. 03*

   Measurements of spin alignment of vector mesons and global polarization of hyperons with ALICE at the LHC

   Bedangadas Mohanty (for the ALICE Collaboration)🇮🇳

   We present the measurements related to global polarization of $\Lambda$ hyperons and spin alignment of ${\mathrm{K}}^{\ast 0}$ vector mesons at mid-rapidity for Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$= 2.76 TeV using the ALICE detector at the LHC. The global polarization measurements are carried out with respect to the first order event plane while the spin alignment measurements are carried out with respect to the production plane. No global polarization signal for $\Lambda$ is observed for 5-15\% and 15-50\% central Pb-Pb collisions. The spin density matrix element ${\rho }_{00}$ is found to have values slightly below 1/3 at low transverse momentum ($p_{\mathrm{T}}$) for ${\mathrm{K}}^{\ast 0}$ mesons, while it is consistent with 1/3 (no spin alignment) at higher $p_{\mathrm{T}}$. No spin alignment is observed for ${\mathrm{K}}^{\ast 0}$ in pp collisions at $\sqrt{s}$ = 13 TeV and for the spin zero hadron ${\mathrm{K}}_{\mathrm{S}}^0$ in 20-40\% Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV.

   nucl-exhep-exhep-phnucl-thEPJ Web Conf.(2018)·19 citations
4. 04*

   Pulse shape discrimination performance of Inverted Coaxial Ge detectors

   A. Domula🇩🇪 · M. Hult🇧🇪 · Y. Kermaidic🇩🇪 · G. Marissens🇧🇪 · B. Schwingenheuer🇩🇪 · T. Wester🇩🇪 · K. Zuber🇩🇪

   We report on the characterization of two inverted coaxial Ge detectors in the context of being employed in future ${}^{76}$Ge neutrinoless double beta ($0\nu \beta \beta$) decay experiments. It is an advantage that such detectors can be produced with bigger Ge mass as compared to the planar Broad Energy Ge detectors (BEGe) that are currently used in the GERDA $0\nu \beta \beta$ decay experiment. This will result in lower background for the search of $0\nu \beta \beta$ decay due to a reduction of cables, electronics and holders. The measured resolution near the ${}^{76}$Ge Q-value at 2039 keV is 2.5 keV and their pulse-shape characteristics are similar to BEGe-detectors. It is concluded that this type of Ge-detector is suitable for usage in ${}^{76}$Ge $0\nu \beta \beta$ decay experiments.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2018)·35 citations
5. 05*

   Upgrade for Phase II of the GERDA Experiment

   M. Agostini🇩🇪 · A.M. Bakalyarov🇷🇺 · M. Balata🇮🇹 · I. Barabanov🇷🇺 · L. Baudis🇨🇭 · C. Bauer🇩🇪 · E. Bellotti🇮🇹 · S. Belogurov🇷🇺 · S.T. Belyaev🇷🇺 · G. Benato🇨🇭 · A. Bettini🇮🇹 · L. Bezrukov🇷🇺 and 102 other authors

   The GERDA collaboration is performing a sensitive search for neutrinoless double beta decay of ${}^{76}$Ge at the INFN Laboratori Nazionali del Gran Sasso, Italy. The upgrade of the GERDA experiment from Phase I to Phase II has been concluded in December 2015. The first Phase II data release shows that the goal to suppress the background by one order of magnitude compared to Phase I has been achieved. GERDA is thus the first experiment that will remain background-free up to its design exposure (100 kg yr). It will reach thereby a half-life sensitivity of more than 10${}^{26}$ yr within 3 years of data collection. This paper describes in detail the modifications and improvements of the experimental setup for Phase II and discusses the performance of individual detector components.

   ↳ physics.ins-detnucl-exEPJC(2018)·118 citations
6. 06*

   Photo- and Electro-excitation of Bound Neutrons and Protons

   Satoshi X. Nakamura (Universidade Cruzeiro do Sul)🇯🇵

   Data for pion photo-productions off the neutron ($\gamma n\to \pi N$) have been primarily extracted from deuteron-target data ($\gamma d\to \pi NN$) by applying kinematical cuts thereby isolating the quasi-free samples. We critically examine if the neutron-target data obtained through this conventional procedure can be contaminated by final state interactions (FSI) and/or the kinematical cuts. The analysis is conducted with a theoretical model for $\gamma d\to \pi NN$ that takes account of the impulse mechanisms supplemented by the $NN$ and $\pi N$ rescattering mechanisms. We show that the FSI effects still visibly remain in the extracted $\gamma$`$n$'$\to \pi N$ unpolarized cross sections and polarization asymmetries $E$ even after the kinematical cuts are applied. We also find the FSI effects on $\gamma$`$n$'$\to {\pi }^{0}n$ can be somewhat different from those on $\gamma$`$p$'$\to {\pi }^{0}p$.

   ↳ nucl-thhep-phnucl-exFew Body Syst.(2018)·2 citations
7. 07*

   Hidden charm pentaquark and $\Lambda (1405)$ in the ${\Lambda }_b^0\to {\eta }_c{K}^{-}p(\pi \Sigma )$ reaction

   Ju-Jun Xie🇨🇳 · Wei-Hong Liang🇨🇳 · Eulogio Oset🇪🇸

   We have performed a study of the ${\Lambda }_b^0\to {\eta }_c{K}^{-}p$ and ${\Lambda }_b^0\to {\eta }_c\pi \Sigma$ reactions based on the dominant Cabibbo favored weak decay mechanism. We show that the $K^{-}p$ produced only couples to ${\Lambda }^{\ast }$ states, not ${\Sigma }^{\ast }$ and that the $\pi \Sigma$ state is only generated from final state interaction of $\bar{K}N$ and $\eta \Lambda$ channels which are produced in a primary stage. This guarantees that the $\pi \Sigma$ state is generated in isospin $I=0$ and we see that the invariant mass produces a clean signal for the $\Lambda (1405)$ of higher mass at $1420$ MeV. We also study the ${\eta }_{c}p$ final state interaction, which is driven by the excitation of a hidden charm resonance predicted before. We relate the strength of the different invariant mass distributions and find similar strengths that should be clearly visible in an ongoing LHCb experiment. In particular we predict that a clean peak should be seen for a hidden charm resonance that couples to the ${\eta }_{c}p$ channel in the invariant ${\eta }_{c}p$ mass distribution.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2018)·15 citations
8. 08*

   Measuring Nuclear Spin Dependent Parity Violation With Molecules: Experimental Methods and Analysis of Systematic Errors

   Emine Altuntas · Jeffrey Ammon · Sidney B. Cahn🇺🇸 · David DeMille🇺🇸

   Nuclear spin-dependent parity violation (NSD-PV) effects in atoms and molecules arise from $Z^0$ boson exchange between electrons and the nucleus, and from the magnetic interaction between electrons and the parity-violating nuclear anapole moment. It has been proposed to study NSD-PV effects using an enhancement of the observable effect in diatomic molecules [D. DeMille $\text{et al.}$, Phys. Rev. Lett. $\text{100}$, 023003 (2008)]. Here, we demonstrate measurements of this type with sensitivity surpassing that of any previous atomic PV measurement, using the test system ${}^{138}\mathrm{B}{\mathrm{a}}^{19}\mathrm{F}$. We show that systematic errors associated with our technique can be suppressed to at least the level of the present statistical sensitivity. With $\sim 170$ hours of data, we measure the matrix element, $W$, of the NSD-PV interaction with uncertainty $\delta W/(2\pi )<0.7$ Hz, for each of two configurations where $W$ must have different signs. This sensitivity would be sufficient to measure NSD-PV effects of the size anticipated across a wide range of nuclei.

   ↳ physics.atom-phnucl-exPRA(2018)·27 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.