Fri·May 29, 2020Friday·May 29, 2020

1. 01*

   Studies of dense nuclear matter at NICA

   Peter Senger🇩🇪

   Laboratory experiments with high-energetic heavy-ion collisions offer the opportunity to explore fundamental properties of nuclear matter, such as the high-density equation-of-state, which governs the structure and dynamics of cosmic objects and phenomena like neutron stars, supernova explosions, and neutron star mergers. A particular goal and challenge of the experiments is to unravel the microscopic degrees-of-freedom of strongly interaction matter at high density, including the search for phase transitions, which may feature a region of phase coexistence and a critical endpoint. As the theory of strong interaction is not able to make firm predictions for the structure and the properties of matter high baryon chemical potentials, the scientific progress in this field is driven by experimental results. The mission of future experiments at FAIR and NICA, which will complement the running experimental programs at GSI, CERN, and RHIC, is to explore new diagnostic probes, which never have been measured before at collision energies, where the highest net-baryon densities will be created. The most promising observables, which are expected to shed light on the nature of high-density QCD matter, comprise the collective flow of identified particles including multi-strange (anti-) hyperons, fluctuations and correlations, lepton pairs, and charmed particles. In the following, the perspectives for experiments in the NICA energy range will be discussed.

   nucl-exnucl-th8 citations
2. 02*

   Quasi parton distribution functions at NNLO: flavor non-diagonal quark contributions

   Long-Bin Chen🇨🇳 · Wei Wang🇨🇳 · Ruilin Zhu🇨🇳

   We present a next-to-next-to-leading order (NNLO) calculation of the quasi parton distribution functions (Quasi-PDFs) in the large momentum effective theory (LaMET). We focus on the flavor non-diagonal quark-quark channel and demonstrate the LaMET factorization at the NNLO accuracy in the modified minimal subtraction scheme. The matching coefficient between the quasi-PDF and the light-cone PDF is derived. This provides a first step towards a complete NNLO analysis of quasi-PDFs and to better understand the nucleon structures from the first principle of QCD.

   ↳ hep-phhep-exhep-latnucl-ex+1PRD(2020)·39 citations
3. 03*

   The first search for bosonic super-WIMPs with masses up to 1 MeV/c${}^2$ with GERDA

   GERDA collaboration: M. Agostini · A. M. Bakalyarov · M. Balata · I. Barabanov · L. Baudis · C. Bauer · E. Bellotti · S. Belogurov · A. Bettini · L. Bezrukov · D. Borowicz · E. Bossio and 96 other authors

   We present the first search for bosonic super-WIMPs as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless double-beta decay experiment which operates high-purity germanium detectors enriched in ${}^{76}$Ge in an ultra-low background environment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for pseudoscalar and vector particles in the mass region from 60 keV/c${}^2$ to 1 MeV/c${}^2$. No evidence for a dark matter signal was observed, and the most stringent constraints on the couplings of super-WIMPs with masses above 120 keV/c${}^2$ have been set. As an example, at a mass of 150 keV/c${}^2$ the most stringent direct limits on the dimensionless couplings of axion-like particles and dark photons to electrons of $g_{ae}<3\cdot 10^{-12}$ and ${\alpha }^{\prime }/\alpha <6.5\cdot 10^{-24}$ at 90% credible interval, respectively, were obtained.

   ↳ hep-exnucl-exPRL(2020)·61 citations
4. 04*

   Barium Selective Chemosensing by Diazacrown Ether Naphthalimide Turn-on Fluorophores for Single Ion Barium Tagging

   P. Thapa · N. K. Byrnes · A. A. Denisenko · F.W. Foss · Jr. · B.J.P. Jones · J. X. Mao · K. Nam · C.A. Newhouse · D.R. Nygren · A.D. McDonald · T.T. Vuong · K. Woodruff

   Single molecule fluorescence detection of barium is investigated for enhancing the sensitivity and robustness of a neutrinoless double beta decay ($0\nu \beta \beta$) search in ${}^{136}$Xe, the discovery of which would alter our understanding of the nature of neutrinos and the early history of the Universe. A key developmental step is the synthesis of barium-selective chemosensors capable of incorporation into ongoing experiments in high-pressure ${}^{136}$Xe gas. Here we report turn-on fluorescent naphthalimide chemosensors containing monoaza- and diaza-crown ethers as agents for single Ba${}^{2+}$ detection. Monoaza-18-crown-6 ether naphthalimide sensors showed sensitivity primarily to Ba${}^{2+}$ and Hg${}^{2+}$, whereas two diaza-18-crown-6 ether naphthalimides revealed a desirable selectivity toward Ba${}^{2+}$. Solution-phase fluorescence and NMR experiments support a photoinduced electron transfer mechanism enabling turn-on fluorescence sensing in the presence of barium ions. Changes in ion-receptor interactions enable effective selectivity between competitive barium, mercury, and potassium ions, with detailed calculations correctly predicting fluorescence responses. With these molecules, dry-phase single Ba${}^{2+}$ ion imaging with turn-on fluorescence is realized using oil-free microscopy techniques. This represents a significant advance toward a practical method of single Ba${}^{2+}$ detection within large volumes of ${}^{136}$Xe, plausibly enabling a background-free technique to search for the hypothetical process of $0\nu \beta \beta$.

   ↳ physics.ins-dethep-exnucl-exphysics.chem-ph6 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.