Fri·Jun 7, 2019Friday·June 7, 2019

1. 01*

   Ground State Electromagnetic Moments of ${}^{37}$Ca

   A. Klose · K. Minamisono🇺🇸 · A. J. Miller🇺🇸 · B. A. Brown🇺🇸 · D. Garand · J. D. Holt🇨🇦 · J. D. Lantis · Y. Liu🇺🇸 · B. Maaß🇩🇪 · W. Nörtershäuser🇩🇪 · S. V. Pineda🇺🇸 · D. M. Rossi and 5 other authors

   The hyperfine coupling constants of neutron deficient ${}^{37}$Ca were deduced from the atomic hyperfine spectrum of the $4s{}^2{S}_{1/2}$ $\leftrightarrow$ $4p{}^2{P}_{3/2}$ transition in Ca II, measured using the collinear laser spectroscopy technique. The ground-state magnetic-dipole and spectroscopic electric-quadrupole moments were determined for the first time as $\mu =+0.7453(72){\mu }_N$ and $Q=-15(11)$ $e^2$fm${}^2$, respectively. The experimental values agree well with nuclear shell model calculations using the universal sd model-space Hamiltonians versions A and B (USDA/B) in the $sd$-model space with a 95\% probability of the canonical nucleon configuration. It is shown that the magnetic moment of ${}^{39}$Ca requires a larger non-$sd$-shell component than that of ${}^{37}$Ca for good agreement with the shell-model calculation, indicating a more robust closed sub-shell structure of ${}^{36}$Ca at the neutron number $N$ = 16 than ${}^{40}$Ca. The results are also compared to valence-space in-medium similarity renormalization group calculations based on chiral two- and three-nucleon interactions.

   nucl-exnucl-thPRC(2019)·20 citations
2. 02*

   Write-ups for workshop on the project for the hadron experimental facility of J-PARC, Partial collection of LOIs at the extended hadron hall and the related topics

   Hadron Hall Users' Association · P.Achenbach (1,2) · J.K.Ahn (3) · S.Ajimura (4) · T.Akaishi (5) · Y.Akaishi (6,7) · W.Ikegami Andersson (8) · K.Aoki (7,9) · H.Asano (6) · S.Bleser (1) · E.Botta (10,11) · M.Bölting (1) and 39 other authors

   This write-up document is a summary of International workshop on the project for the extended hadron experimental facility which was held from March 26 to 28, 2018 at KEK Tokai Campus. This document is a collection of Letter Of Intents (LOIs) related to the proposed beam lines in the extended hadron experimental facility at J-PARC.

   nucl-exhep-ex10 citations
3. 03*

   Probing high-energy interactions of atmospheric and astrophysical neutrinos

   Spencer R. Klein🇺🇸

   Astrophysical and atmospheric neutrinos are important probes of the powerful accelerators that produce cosmic-rays with EeV energies. Understanding these accelerators is a key goal of neutrino observatories, along with searches for neutrinos from supernovae, from dark matter annihilation, and other astrophysics topics. Here, we discuss how neutrino observatories like IceCube and future facilities like KM3NeT and IceCube-Gen2 can study the properties of high-energy (above 1 TeV) neutrino interactions. This is far higher than is accessible at man-made accelerators, where the highest energy neutrino beam reached only 500 GeV. In contrast, neutrino observatories have observed events with energies above 5 PeV - 10,000 times higher in energy - and future large observatories may probe neutrinos with energies up to $10^{20}$ eV. These data have implications for both Standard Model measurements, such as of low Bjorken$-x$ parton distributions and gluon shadowing, and also for searches for beyond Standard Model physics. This chapter will review the existing techniques and results, and discuss future prospects.

   ↳ astro-ph.HEhep-exnucl-ex21 citations
4. 04*

   High-precision characterization of the neutron light output of stilbene along the directions of maximum and minimum response

   R. A. Weldon Jr. · J. M. Mueller🇺🇸 · C. Lynch · P. Schuster · S. Hedges🇺🇸 · C. Awe🇺🇸 · L. Li🇺🇸 · P. Barbeau🇺🇸 · J. Mattingly

   The scintillation light output response of stilbene crystals has been measured for protons recoiling along the \textit{a}, \textit{b}, and \textit{c'} crystalline axes with energies between 1.3 and 10 MeV using neutrons produced with the tandem Van de Graaff accelerator at Triangle Universities Nuclear Laboratory. The proton recoil energy and direction were measured using the coincident detection of neutrons between a stilbene scintillator and an array of EJ-309 liquid scintillators spanning arranged neutron recoil angles. The maximum light output was found to coincide with proton recoils along the \textit{a}-axis, in disagreement with other published measurements, which reported the \textit{b}-axis as the direction of the maximum light output. Additional measurements were conducted using two different stilbene crystals to confirm these results: a second measurement using the coincident detection of neutrons; measurements of neutron full energy deposition events along the \textit{a} and \textit{b} axes; and measurements of the count rate for ${}^{252}$Cf neutrons traveling along the \textit{a} and \textit{b} axes directions. All measurements found that recoils along the \textit{a}-axis produce the maximum light output.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2019)·4 citations
5. 05*

   ALICE Highlights

   Francesco Noferini🇮🇹

   Deconfined strongly interacting QCD matter is produced in the laboratory at the highest energy densities in heavy-ion collisions at the LHC. A selection of recent results from ALICE is presented, spanning observables from the soft sector (bulk particle production and correlations), the hard probes (charmed hadrons and jets) and signatures of possible collective effects in pp and p-Pb collisions with high multiplicity. Finally, the perspectives after the detectors upgrades, taking place in the period 2019-2020, are presented.

   ↳ hep-exnucl-exMDPI Proc.(2019)·6 citations
6. 06*

   Leading order corrections to the Bethe-Heitler process in the $\gamma p\to l^{+}{l}^{-}p$ reaction

   Matthias Heller🇩🇪 · Oleksandr Tomalak🇩🇪 · Marc Vanderhaeghen🇩🇪 · Shihao Wu🇨🇦

   The ratio of di-lepton production cross sections on a proton, using the $\gamma p\to l^{+}{l}^{-}p$ process, above and below di-muon production threshold allows to extract the effective lepton-proton interaction, which is required to be identical for electrons and muons if lepton universality is exact. To test for a scenario of broken universality at the percent level, of the size which could explain the different proton charge radii extracted from electron scattering and from muonic hydrogen spectroscopy, we evaluate all one-loop QED corrections to this process, including the full lepton mass dependencies. We furthermore show that two-photon exchange processes with both photons attached to the proton line vanish after averaging over di-lepton angles, and estimate the relatively small radiation off the proton. We compare the full one-loop calculation with a soft-photon approximation of the same order, and present estimates for a planned experiment.

   ↳ hep-phnucl-exnucl-thPRD(2019)·16 citations
7. 07*

   Search for Neutrinoless Double-Beta Decay with the Complete EXO-200 Dataset

   G. Anton🇩🇪 · I. Badhrees🇨🇦 · P.S. Barbeau🇺🇸 · D. Beck🇺🇸 · V. Belov🇷🇺 · T. Bhatta🇺🇸 · M. Breidenbach🇺🇸 · T. Brunner🇨🇦 · G.F. Cao🇨🇳 · W.R. Cen🇨🇳 · C. Chambers🇺🇸 · B. Cleveland🇨🇦 and 90 other authors

   A search for neutrinoless double-beta decay ($0\nu \beta \beta$) in ${}^{136}$Xe is performed with the full EXO-200 dataset using a deep neural network to discriminate between $0\nu \beta \beta$ and background events. Relative to previous analyses, the signal detection efficiency has been raised from 80.8% to 96.4$\pm$3.0% and the energy resolution of the detector at the Q-value of ${}^{136}$Xe $0\nu \beta \beta$ has been improved from $\sigma /E=1.23\%$ to $1.15\pm 0.02\%$ with the upgraded detector. Accounting for the new data, the median 90% confidence level $0\nu \beta \beta$ half-life sensitivity for this analysis is $5.0\cdot 10^{25}$ yr with a total ${}^{136}$Xe exposure of 234.1 kg$\cdot$yr. No statistically significant evidence for $0\nu \beta \beta$ is observed, leading to a lower limit on the $0\nu \beta \beta$ half-life of $3.5\cdot 10^{25}$ yr at the 90% confidence level.

   ↳ hep-exnucl-exPRL(2019)·404 citations
8. 08*

   Longitudinal double-spin asymmetry for inclusive jet and dijet production in $pp$ collisions at $\sqrt{s}=510$ GeV

   STAR Collaboration: J. Adam🇺🇸 · L. Adamczyk🇵🇱 · J. R. Adams🇺🇸 · J. K. Adkins🇺🇸 · G. Agakishiev🇷🇺 · M. M. Aggarwal🇮🇳 · Z. Ahammed🇮🇳 · I. Alekseev🇷🇺 · D. M. Anderson🇺🇸 · R. Aoyama🇯🇵 · A. Aparin🇷🇺 · D. Arkhipkin🇺🇸 and 340 other authors

   We report the first measurement of the inclusive jet and the dijet longitudinal double-spin asymmetries, $A_{LL}$, at midrapidity in polarized $pp$ collisions at a center-of-mass energy $\sqrt{s}=510$ GeV. The inclusive jet $A_{LL}$ measurement is sensitive to the gluon helicity distribution down to a gluon momentum fraction of $x\approx 0.015$, while the dijet measurements, separated into four jet-pair topologies, provide constraints on the $x$ dependence of the gluon polarization. Both results are consistent with previous measurements made at $\sqrt{s}=200$ GeV in the overlapping kinematic region, $x>0.05$, and show good agreement with predictions from recent next-to-leading order global analyses.

   ↳ hep-exnucl-exPRD(2019)·95 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.