Fri·Mar 27, 2020Friday·March 27, 2020

1. 01*

   Structure of high-lying levels populated in the ${}^{96}$Y ${\to }^{96}$Zr $\beta$ decay

   K.R. Mashtakov🇬🇧 · V.Yu. Ponomarev🇩🇪 · M. Scheck🇬🇧 · S.W. Finch🇺🇸 · J. Isaak🇩🇪 · M. Zweidinger🇩🇪 · O. Agar🇹🇷 · C. Bathia🇺🇸 · T. Beck🇩🇪 · J. Beller🇩🇪 · M. Bowry🇬🇧 · R. Chapman🇬🇧 and 23 other authors

   The nature of $J^{\pi }=1^{-}$ levels of ${}^{96}$Zr below the $\beta$-decay $Q_{\beta }$ value of ${}^{96}$Y has been investigated in high-resolution $\gamma$-ray spectroscopy following the $\beta$ decay as well as in a campaign of inelastic photon scattering experiments. Branching ratios extracted from $\beta$ decay allow the absolute $E1$ excitation strength to be determined for levels populated in both reactions. The combined data represents a comprehensive approach to the wavefunction of $1^{-}$ levels below the $Q_{\beta }$ value, which are investigated in the theoretical approach of the Quasiparticle Phonon Model. This study clarifies the nuclear structure properties associated with the enhanced population of high-lying levels in the ${}^{96}$Y${}_{gs}$ $\beta$ decay, one of the three most important contributors to the high-energy reactor antineutrino spectrum.

   nucl-exPLB(2021)·5 citations
2. 02*

   Nucleon elastic form factors at accessible large spacelike momenta

   Zhu-Fang Cui🇨🇳 · Chen Chen🇩🇪 · Daniele Binosi🇮🇹 · Feliciano De Soto🇪🇸 · Craig D. Roberts🇨🇳 · Jose Rodriguez-Quintero🇪🇸 · Sebastian M. Schmidt🇩🇪 · Jorge Segovia🇪🇸

   A Poincaré-covariant quark+diquark Faddeev equation is used to compute nucleon elastic form factors on $0\le Q^2\le 18m_N^2$ ($m_N$ is the nucleon mass) and elucidate their role as probes of emergent hadronic mass in the Standard Model. The calculations expose features of the form factors that can be tested in new generation experiments at existing facilities, e.g. a zero in $G_E^p/G_M^p$; a maximum in $G_E^n/G_M^n$; and a zero in the proton's $d$-quark Dirac form factor, $F_1^d$. Additionally, examination of the associated light-front-transverse number and anomalous magnetisation densities reveals, inter alia: a marked excess of valence $u$-quarks in the neighbourhood of the proton's centre of transverse momentum; and that the valence $d$-quark is markedly more active magnetically than either of the valence $u$-quarks. The calculations and analysis also reveal other aspects of nucleon structure that could be tested with a high-luminosity accelerator capable of delivering higher beam energies than are currently available.

   ↳ hep-phhep-latnucl-exnucl-thPRD(2020)·52 citations
3. 03*

   A Comprehensive Monte Carlo Framework for Jet-Quenching

   R.A. Soltz🇺🇸

   This article presents the motivation for developing a comprehensive modeling framework in which different models and parameter inputs can be compared and evaluated for a large range of jet-quenching observables measured in relativistic heavy-ion collisions at RHIC and the LHC. The concept of a framework us discussed within the context of recent efforts by the JET Collaboration, the authors of JEWEL, and the JETSCAPE collaborations. The framework ingredients for each of these approaches is presented with a sample of important results from each. The role of advanced statistical tools in comparing models to data is also discussed, along with the need for a more detailed accounting of correlated errors in experimental results.

   ↳ physics.data-annucl-exnucl-thNPA(2021)·2 citations
4. 04*

   Antiproton over proton and K${}^{-}$ over K${}^{+}$ multiplicity ratios at high $z$ in DIS

   M.G. Alexeev🇷🇺 · G.D. Alexeev🇮🇹 · A. Amoroso🇮🇹 · V. Andrieux🇺🇸 · V. Anosov🇷🇺 · A. Antoshkin🇷🇺 · K. Augsten🇷🇺 · W. Augustyniak🇵🇱 · C.D.R. Azevedo🇵🇹 · B. Badelek🇵🇱 · F. Balestra🇮🇹 · M. Ball🇩🇪 and 187 other authors

   The $\bar{\mathrm{p}}$ over p multiplicity ratio is measured in deep-inelastic scattering for the first time using (anti-) protons carrying a large fraction of the virtual-photon energy, $z>0.5$. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar ${}^6$LiD target. The regime of deep-inelastic scattering is ensured by requiring $Q^2$ > 1 (GeV/$c$)${}^2$ for the photon virtuality and $W>5$ GeV/$c^2$ for the invariant mass of the produced hadronic system. The range in Bjorken-$x$ is restricted to $0.01<x<0.40$. Protons and antiprotons are identified in the momentum range $20÷60$ GeV/$c$. In the whole studied $z$-region, the $\bar{\mathrm{p}}$ over p multiplicity ratio is found to be below the lower limit expected from calculations based on leading-order perturbative Quantum Chromodynamics (pQCD). Extending our earlier analysis of the K${}^{-}$ over K${}^{+}$ multiplicity ratio by including now events with larger virtual-photon energies, this ratio becomes closer to the expectation of next-to-leading order pQCD. The results of both analyses strengthen our earlier conclusion that the phase space available for hadronisation should be taken into account in the pQCD formalism.

   ↳ hep-exnucl-exPLB(2020)·6 citations
5. 05*

   Searching for New Physics in Two-Neutrino Double Beta Decay

   Frank F. Deppisch🇬🇧 · Lukas Graf🇩🇪 · Fedor Šimkovic🇸🇰

   Motivated by non-zero neutrino masses and the possibility of New Physics discovery, a number of experiments search for neutrinoless double beta decay. While hunting for this hypothetical nuclear process, a significant amount of two-neutrino double beta decay data has become available. Although these events are regarded and studied mostly as the background of neutrinoless double beta decay, they can be also used to probe physics beyond the Standard Model. In this paper we show how the presence of right-handed leptonic currents would affect the energy distribution and angular correlation of the outgoing electrons in two-neutrino double beta decay. Consequently, we estimate constraints imposed by currently available data on the existence of right-handed neutrino interactions without having to assume their nature. In this way our results complement the bounds coming from the non-observation of neutrinoless double beta decay as they limit also the exotic interactions of Dirac neutrinos. We perform a detailed calculation of two-neutrino double beta decay under the presence of exotic (axial-)vector currents and we demonstrate that current experimental searches can be competitive to existing limits.

   ↳ hep-phnucl-exnucl-thPRL(2020)·58 citations
6. 06*

   The energy calibration system for CANDLES using (n, \gamma) reaction

   T. Iida🇯🇵 · K. Mizukoshi🇯🇵 · T. Ohata🇯🇵 · T. Uehara🇯🇵 · T. Batpurev🇯🇵 · W. M. Chan · K. Fushimi🇯🇵 · R. Hazama🇯🇵 · M. Ishikawa🇯🇵 · H. Kakubata🇯🇵 · K. Kanagawa🇯🇵 · S. Katagiri🇯🇵 and 19 other authors

   CAlcium fluoride for the study of Neutrinos and Dark matters by Low-energy Spectrometer (CANDLES) searches for neutrino-less double beta decay of ${}^{48}$Ca using a CaF${}_2$ scintillator array. A high Q-value of ${}^{48}$Ca at 4,272 keV enabled us to achieve very low background condition, however, at the same it causes difficulties in calibrating the detector's Q-value region because of the absence of a standard high-energy $\gamma$-ray source. Therefore, we have developed a novel calibration system based on $\gamma$-ray emission by neutron capture on ${}^{28}$Si, ${}^{56}$Fe and ${}^{58}$Ni nuclei. In the paper, we report the development of the new calibration system as well as the results of energy calibration in CANDLES up to 9 MeV.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2021)·9 citations
7. 07*

   Sensitivity of the DARWIN observatory to the neutrinoless double beta decay of ${}^{136}$Xe

   F. Agostini🇮🇹 · S. E. M. Ahmed Maouloud🇫🇷 · L. Althueser🇩🇪 · F. Amaro🇵🇹 · B. Antunovic🇷🇸 · E. Aprile🇺🇸 · L. Baudis🇨🇭 · D. Baur🇩🇪 · Y. Biondi🇨🇭 · A. Bismark🇨🇭 · P. A. Breur🇳🇱 · A. Brown🇨🇭 and 83 other authors

   The DARWIN observatory is a proposed next-generation experiment to search for particle dark matter and for the neutrinoless double beta decay of ${}^{136}$Xe. Out of its 50t total natural xenon inventory, 40t will be the active target of a time projection chamber which thus contains about 3.6 t of ${}^{136}$Xe. Here, we show that its projected half-life sensitivity is $2.4\times 10^{27}$yr, using a fiducial volume of 5t of natural xenon and 10yr of operation with a background rate of less than 0.2 events/(t$\cdot$yr) in the energy region of interest. This sensitivity is based on a detailed Monte Carlo simulation study of the background and event topologies in the large, homogeneous target. DARWIN will be comparable in its science reach to dedicated double beta decay experiments using xenon enriched in ${}^{136}$Xe.

   ↳ physics.ins-dethep-exnucl-exEPJC(2020)·88 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.