Fri·Dec 6, 2019Friday·December 6, 2019

1. 01*

   Hadron Physics at J-PARC

   Hiroaki Ohnishi🇯🇵 · Fuminori Sakuma🇯🇵 · Toshiyuki Takahashi🇯🇵

   The aim of the hadron physics research programs conducted at J-PARC is to explore the structure of hadronic matter using the world's highest-intensity meson beams. Since the first beam was extracted at the hadron experimental facility (HEF) in February 2009, a wide variety of physics experiments have been proposed and performed to address open questions regarding quantum chromodynamics (QCD) at low energy. The high-intensity $K^{-}$ and high-momentum beams available at J-PARC open a new era in hadron and nuclear physics, in which strange and charm quarks play an important role. We review the programs focused on addressing the hadron structure as strongly interacting composite particles, the origin of hadron mass, and interactions between hadrons under broken flavor SU(3) symmetry.

   nucl-exnucl-thPPNP(2020)·43 citations
2. 02*

   Detailed spectroscopy of ${}^{46}$Ca: A study of the ${\beta }^{-}$ decay of ${}^{46}$K

   J.L. Pore🇨🇦 · C. Andreoiu🇨🇦 · J.K. Smith🇨🇦 · A.D. MacLean🇨🇦 · A. Chester🇨🇦 · J.D. Holt🇨🇦 · G.C. Ball🇨🇦 · P.C. Bender🇨🇦 · V. Bildstein🇨🇦 · R. Braid🇺🇸 · A. Diaz Varela🇨🇦 · R. Dunlop🇨🇦 and 24 other authors

   We report on high-statistics data from the ${\beta }^{-}$ decay of the ${}^{46}$K $J^{\pi }$ = 2${}^{-}$ ground state taken with the GRIFFIN spectrometer located at the TRIUMF-ISAC facility. In total, 199 $\gamma$ rays and 42 excited states were placed in the level scheme, and from the observed $\beta$ feeding and angular correlations of pairs of cascading $\gamma$ rays, it was possible to assign spins and parities to excited states and determine mixing ratios for selected $\gamma$ rays. The level structure of ${}^{46}$Ca is compared to theoretical predictions from a microscopic valence-space Hamiltonian derived from two- (NN) and three-nucleon (3N) forces. These calculations are in reasonable agreement with the experimental data and indicate that the protons in this region are not as inert as would be expected for semi-magic nuclei.

   nucl-exPRC(2019)·5 citations
3. 03*

   Search for two neutrino double electron capture of ${}^{124}$Xe and ${}^{126}$Xe in the full exposure of the LUX detector

   LUX Collaboration: D. S. Akerib🇺🇸 · S. Alsum🇺🇸 · H. M. Araújo🇬🇧 · X. Bai🇺🇸 · J. Balajthy🇺🇸 · A. Baxter🇬🇧 · E. P. Bernard🇺🇸 · A. Bernstein🇺🇸 · T. P. Biesiadzinski🇺🇸 · E. M. Boulton🇺🇸 · B. Boxer🇬🇧 · P. Brás🇵🇹 and 86 other authors

   Two-neutrino double electron capture is a process allowed in the Standard Model of Particle Physics. This rare decay has been observed in ${}^{78}$Kr, ${}^{130}$Ba and more recently in ${}^{124}$Xe. In this publication we report on the search for this process in ${}^{124}$Xe and ${}^{126}$Xe using the full exposure of the Large Underground Xenon (LUX) experiment, in a total of of 27769.5~kg-days. No evidence of a signal was observed, allowing us to set 90\% C.L. lower limits for the half-lives of these decays of $2.0\times 10^{21}$~years for ${}^{124}$Xe and $1.9\times 10^{21}$~years for ${}^{126}$Xe.

   nucl-exphysics.ins-detJ.Phys.G(2020)·10 citations
4. 04*

   Double parton scattering in pA collisions at the LHC revisited

   B.Blok🇮🇱 · F.A. Ceccopieri🇮🇱

   We consider the production of $W$-boson plus dijet, $W$-boson plus b-jets and same sign $WW$ via double parton scattering (DPS) in $pA$ collisions at the LHC and evaluate the corresponding cross sections. The impact of a novel DPS contribution pertinent to $pA$ collisions is quantified. Exploiting the experimental capability of performing measurements differential in the impact parameter in $pA$ collisions, we discuss a method to single out this novel DPS contribution. The method allows the subtraction of the leading twist (LT) single parton scattering background and it gives access in a very clean way to double parton distribution functions in the proton. We calculate leading twist and DPS cross sections and study the dependence of the observables on the cuts in the jets phase space. In the $Wjj$ channel the observation of DPS is possible with data already accumulated in $pA$ runs and the situation will greatly improve for the next high luminosity runs. For the $Wb\bar{b}$ final state, the statistics within the current data is too low, but there is possibility to observe DPS in this channel in future runs, albeit with much reduced sensitivity than in $Wjj$ final state. Finally the DPS observation in the same sign $WW$ channel will require either significant increase of integrated luminosity beyond that foreseen in next $pA$ runs or improved methods for $W$ reconstruction, along with its charge, in hadronic decay channels.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2020)·9 citations
5. 05*

   Transverse wobbling in an even-even nucleus

   Q. B. Chen🇩🇪 · S. Frauendorf🇺🇸 · C. M. Petrache🇫🇷

   Two new bands built on the two-quasiparticle $\pi (h_{11/2}{)}^2$ configuration of the even-even nucleus ${}^{130}$Ba are investigated using constrained triaxial covariant density functional theory combined with quantum particle rotor model calculations. The energy difference between the two bands, as well as the available electromagnetic transition probabilities $B(M1{)}_{\text{out}}/B(E2{)}_{\text{in}}$ and $B(E2{)}_{\text{out}}/B(E2{)}_{\mathrm{in}}$, are well reproduced. The analysis of the angular momentum geometry reveals that the higher band represents transverse wobbling motion of a two-quasiparticle configuration. This is the first example of two-quasiparticle wobbling bands in an even-even nucleus.

   ↳ nucl-thnucl-exPRC(2019)·51 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.