Tue·Nov 7, 2023Tuesday·November 7, 2023

1. 01*

   An improved limit on the neutrinoless double-electron capture of ${}^{36}$Ar with GERDA

   GERDA Collaboration: M. Agostini🇬🇧 · A. Alexander🇬🇧 · G. R. Araujo🇨🇭 · A. M. Bakalyarov🇷🇺 · M. Balata🇮🇹 · I. Barabanov🇷🇺 · L. Baudis🇨🇭 · C. Bauer🇩🇪 · S. Belogurov🇷🇺 · A. Bettini🇮🇹 · L. Bezrukov🇷🇺 · V. Biancacci🇮🇹 and 100 other authors

   The GERmanium Detector Array (GERDA) experiment operated enriched high-purity germanium detectors in a liquid argon cryostat, which contains 0.33% of ${}^{36}$Ar, a candidate isotope for the two-neutrino double-electron capture (2$\nu$ECEC) and therefore for the neutrinoless double-electron capture (0$\nu$ECEC). If detected, this process would give evidence of lepton number violation and the Majorana nature of neutrinos. In the radiative 0$\nu$ECEC of ${}^{36}$Ar, a monochromatic photon is emitted with an energy of 429.88 keV, which may be detected by the GERDA germanium detectors. We searched for the ${}^{36}$Ar 0$\nu$ECEC with GERDA data, with a total live time of 4.34 yr (3.08 yr accumulated during GERDA Phase II and 1.26 yr during GERDA Phase I). No signal was found and a 90% C.L. lower limit on the half-life of this process was established T${}_{1/2}$ > 1.5x10${}^{22}$ yr

   nucl-exEPJC(2024)·7 citations
2. 02*

   Study the isomeric ratios in photonuclear experiments on the LUE-40 linac RDC "Accelerator" NSC KIPT

   I.S. Timchenko🇸🇰 · O.S. Deiev🇺🇦 · S.M. Olejnik🇺🇦 · S.M. Potin🇺🇦 · V.A. Kushnir🇺🇦 · V.V. Mytrochenko🇺🇦 · S.A. Perezhogin🇺🇦

   The results of the photoproduction of isomeric pairs from the ({\gamma},xn) and ({\gamma},pxn) reactions on nuclei from Zr up to Ta at the bremsstrahlung end-point energy range 30-100 MeV are systematized. Measurements were performed at the electron beam of the LUE-40 linac RDC "Accelerator" NSC KIPT using the activation method and off-line {\gamma}-ray spectrometric technique. The theoretical isomeric ratios IR for the nuclei-products of studied reactions were calculated using the cross-sections {\sigma}(E) from the TALYS1.95 code for six different level density models. The data from the international databases were additionally used to compare experimental results and theoretical predictions. The obtained results let us make conclusions about trends of values and energy dependence of IR in studied photonuclear reactions. Further directions of experimental research in the RDC "Accelerator" NSC KIPT are discussed.

   nucl-exProb.Atomic Sci.Technol.(2023)·0 citations
3. 03*

   Cross-section of the ${}^{95}\mathrm{Nb}$ production on natural molybdenum at the bremsstrahlung end-point energy up to 95 MeV

   I.S. Timchenko🇸🇰 · O.S. Deiev🇺🇦 · S.M. Olejnik🇺🇦 · S.M. Potin🇺🇦 · V.A. Kushnir🇺🇦 · V.V. Mytrochenko🇺🇦 · S.A. Perezhogin🇺🇦

   The photoproduction of ${}^{95\mathrm{m}}$Nb on ${}^{\mathrm{nat}}\mathrm{Mo}$ was studied using the electron beam of the LUE-40 linac RDC "Accelerator" NSC KIPT. Measurements were performed using activation and off-line $\gamma$-ray spectrometric techniques. The experimental flux-averaged cross-section $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{m}}$ for the ${}^{\mathrm{nat}}\mathrm{Mo}(\gamma ,x\mathrm{np}{)}^{95\mathrm{m}}$Nb reaction at the bremsstrahlung end-point energy range of 38--93 MeV has been first time obtained. The estimated values $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{g}}$ for the formation of ${}^{95}$Nb in the ground state and total cross-sections $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{tot}}$ for the studied reaction were determined. The theoretical values of the yields $Y_{\mathrm{m},\mathrm{g},\mathrm{tot}}(E_{\gamma \max })$ and flux-averaged cross-sections $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{m},\mathrm{g},\mathrm{tot}}$ for the ${}^{\mathrm{nat}}\mathrm{Mo}(\gamma ,x\mathrm{np}{)}^{95\mathrm{m},\mathrm{g},\mathrm{tot}}$Nb reactions were calculated using the cross-sections $\sigma (E)$ from the TALYS1.95 code for six different level density models. The comparison showed a significant excess of the experimental results over the theoretical $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{m},\mathrm{g},\mathrm{tot}}$ values.

   nucl-exEPJA(2024)·3 citations
4. 04*

   Coalescence sum rule and the electric charge- and strangeness-dependences of directed flow in heavy ion collisions

   Kishora Nayak🇮🇳 · Shusu Shi🇨🇳 · Zi-Wei Lin🇺🇸

   The rapidity-odd directed flows ($v_1$) of identified hadrons are expected to follow the coalescence sum rule when the created matter is initially in parton degrees of freedom and then hadronizes through quark coalescence. A recent study has considered the $v_1$ of produced hadrons that do not contain $u$ or $d$ constituent quarks. It has constructed multiple hadron sets with a small mass difference but given difference in electric charge $\Delta q$ and strangeness $\Delta S$ between the two sides, where a nonzero and increasing $\Delta v_1$ with $\Delta q$ has been proposed to be a consequence of electromagnetic fields. In this study, we examine the consequence of coalescence sum rule on the $\Delta v_1$ of the hadron sets in the absence of electromagnetic fields. We find that in general $\Delta v_1\ne 0$ for a hadron set with nonzero $\Delta q$ and/or $\Delta S$ due to potential $v_1$ differences between $\bar{u}$ and $\bar{d}$ and between $s$ and $\bar{s}$ quarks. We further propose methods to extract the coefficients for the $\Delta q$- and $\Delta S$-dependences of the direct flow difference, where a nonzero constant term would indicate the breaking of the coalescence sum rule. The extraction methods are then demonstrated with transport model results.

   ↳ nucl-thnucl-exPLB(2024)·7 citations
5. 05*

   Bayesian calibration of viscous anisotropic hydrodynamic (VAH) simulations of heavy-ion collisions

   Ulrich Heinz (Ohio State Univ.)🇺🇸 · Dananjaya Liyanage (Ohio State Univ.)🇺🇸 · Cullen Gantenberg (Ohio State Univ., Univ. of Washington)🇺🇸

   A Bayesian calibration, using experimental data from 2.76 $A$ TeV Pb-Pb collisions at the LHC, of a novel hybrid model is presented in which the usual pre-hydrodynamic and viscous relativistic fluid dynamic (vRFD) stages are replaced by a viscous anisotropic hydrodynamic (VAH) core that smoothly interpolates between the initial expansion-dominated, approximately boost-invariant longitudinally free-streaming and the subsequent collision-dominated (3+1)-dimensional standard vRFD stages. This model yields meaningful constraints for the temperature-dependent specific shear and bulk viscosities, $(\eta /s)(T)$ and $(\zeta /s)(T)$, for temperatures up to about $700$ MeV (i.e. over twice the range that could be explored with earlier models). With its best-fit model parameters the calibrated VAH model makes highly successful predictions for additional $p_T$-dependent observables for which high-quality experimental data are available that were not used for the model calibration.

   ↳ nucl-thhep-phnucl-exEPJ Web Conf.(2024)·3 citations
6. 06*

   SIDDHARTA-2 apparatus for kaonic atoms research on the DA$\Phi$NE collider

   F. Sirghi · F. Sgaramella · L. Abbene · C. Amsler · M. Bazzi · G. Borghi · D. Bosnar · M. Bragadireanu · A. Buttacavoli · M. Carminati · M. Cargnelli · A. Clozza and 32 other authors

   SIDDHARTA-2 represents a state-of-the-art experiment designed to perform dedicated measurements of kaonic atoms, which are particular exotic atom configurations composed of a negatively charged kaon and a nucleus. Investigating these atoms provides an exceptional tool to comprehend the strong interactions in the non-perturbative regime involving strangeness. The experiment is installed at the DA$\Phi$NE electron-positron collider, of the INFN National Laboratory of Frascati (INFN-LNF) in Italy, aiming to perform the first-ever measurement of the 2p$\to$1s X-ray transitions in kaonic deuterium, a crucial step towards determining the isospin-dependent antikaon-nucleon scattering lengths. Based on the experience gained with the previous SIDDHARTA experiment, which performed the most precise measurement of the kaonic hydrogen 2p$\to$1s X-ray transitions, the present apparatus has been upgraded with innovative Silicon Drift Detectors (SDDs), distributed around a cryogenic gaseous target placed in a vacuum chamber at a short distance above the interaction region of the collider. We present a comprehensive description of the SIDDHARTA-2 setup including the optimization of its various components during the commissioning phase of the collider.

   ↳ physics.ins-detnucl-exJINST(2024)·24 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.