Fri·Jul 2, 2021Friday·July 2, 2021

1. 01*

   Study of (${}^6$Li, $d$) and (${}^6$Li, $t$) reactions on ${}^{22}$Ne and implications for $s$-process nucleosynthesis

   S. Ota🇯🇵 · G. Christian · W. N. Catford🇬🇧 · G. Lotay🇬🇧 · M. Pignatari🇭🇺 · U. Battino🇬🇧 · E. A. Bennett · S. Dede🇺🇸 · D. T. Doherty🇫🇷 · S. Hallam🇬🇧 · F. Herwig🇨🇦 · J. Hooker🇺🇸 and 11 other authors

   We studied $\alpha$ cluster states in ${}^{26}$Mg via the ${}^{22}$Ne(${}^6$Li,$d\gamma$)${}^{26}$Mg reaction in inverse kinematics at an energy of $7$ MeV/nucleon. States between $E_x$ = 4 - 12 MeV in ${}^{26}$Mg were populated and relative $\alpha$ spectroscopic factors were determined. Some of these states correspond to resonances in the Gamow window of the ${}^{22}$Ne($\alpha$,n)${}^{25}$Mg reaction, which is one of the main neutron sources in the astrophysical $s$-process. We show that $\alpha$-cluster strength of the states analyzed in this work have critical impact on s-process abundances. Using our new ${}^{22}$Ne($\alpha$,n)${}^{25}$Mg and ${}^{22}$Ne($\alpha$,$\gamma$)${}^{26}$Mg reaction rates, we performed new s-process calculations for massive stars and Asymptotic Giant Branch stars and compared the resulting yields with the yields obtained using other ${}^{22}$Ne+$\alpha$ rates from the literature. We observe an impact on the s-process abundances up to a factor of three for intermediate-mass AGB stars and up to a factor of ten for massive stars. Additionally, states in ${}^{25}$Mg at $E_x$ $<$ 5 MeV are identified via the ${}^{22}$Ne(${}^6$Li,$t$)${}^{25}$Mg reaction for the first time. We present the (${}^6$Li, $t$) spectroscopic factors of these states and note similarities to the $(d,p$) reaction in terms of reaction selectivity.

   nucl-exPRC(2021)·15 citations
2. 02*

   Relationships among detector signals recorded during events SN1987A and GW170817

   N. Agafonova🇷🇺 · A. Malgin🇷🇺 · E. Fischbach🇺🇸

   The temporal coincidences of events detected in four neutrino detectors and two gravitational antennas still remains among the most puzzling phenomena associated with SN1987A. The coincidences form a six-hour signal approximately coincident in time with the well-known LSD signal at 2h52m UT on 23/02/1987. After 30 years of research, the characteristics and the shape of the six-hour signal have been studied quite well, but the mechanisms of its formation have not been fully understood as of yet. Here we suggest that data obtained from another technology, radioactive decays, might provide new insights into the origin of signals previously seen in neutrino detectors and gravity wave detectors. On August 17, 2017, at 12h41m UT, the GW170817 signal was detected by LIGO and Virgo. At the same time, an approximately 7-hour long signal coincident with GW170817 was detected in the Si/Cl experiment on precision measurement of the ${}^{32}$Si half-life. We show that the Si/Cl signal is unexpectedly similar to the six-hour signal from SN1987A. In addition, we establish that the sources of the coinciding events are similar to those of the Si/Cl signal. To explain the surprising similarities in both signals, we present a mechanism which could in principle account for this phenomenon in terms of a local increase in the density of axionic dark matter induced by a gravity wave.

   nucl-exastro-ph.IMhep-phphysics.ins-det3 citations
3. 03*

   First observation of high-$K$ isomeric states in ${}^{249}$Md and ${}^{251}$Md

   T. Goigoux🇫🇷 · Ch. Theisen🇫🇷 · B. Sulignano🇫🇷 · M. Airiau🇫🇷 · K. Auranen🇫🇮 · H. Badran🇫🇮 · R. Briselet🇫🇷 · T. Calverley🇫🇮 · D. Cox🇫🇮 · F. Déchery🇫🇷 · F. Defranchi Bisso🇫🇮 · A. Drouart🇫🇷 and 36 other authors

   Decay spectroscopy of the odd-proton nuclei ${}^{249}$Md and ${}^{251}$Md has been performed. High-$K$ isomeric states were identified for the first time in these two nuclei through the measurement of their electromagnetic decay. An isomeric state with a half-life of $2.8(5)$ ms and an excitation energy $\ge 910$ keV was found in ${}^{249}$Md. In ${}^{251}$Md, an isomeric state with a half-life of $1.4(3)$ s and an excitation energy $\ge 844$ keV was found. Similarly to the neighbouring ${}^{255}$Lr, these two isomeric states are interpreted as 3 quasi-particle high-$K$ states and compared to new theoretical calculations. Excited nuclear configurations were calculated within two scenarios: via blocking nuclear states located in proximity to the Fermi surface or/and using the quasiparticle Bardeen-Cooper-Schrieffer method. Relevant states were selected on the basis of the microscopic-macroscopic model with a deformed Woods-Saxon potential. The most probable candidates for the configurations of $K$-isomeric states in Md nuclei are proposed.

   nucl-exnucl-thEPJA(2021)·13 citations
4. 04*

   Proton number cumulants and correlation functions in Au-Au collisions at $\sqrt{s_{\mathrm{NN}}}=7.7-200$ GeV from hydrodynamics

   Volodymyr Vovchenko🇺🇸 · Volker Koch🇺🇸 · Chun Shen🇺🇸

   We present a dynamical description of (anti)proton number fluctuations cumulants and correlation functions in central Au-Au collisions at $\sqrt{s_{\mathrm{NN}}}=7.7-200$ GeV by utilizing viscous hydrodynamics simulations. The cumulants of proton and baryon number are calculated in a given momentum acceptance analytically, via an appropriately extended Cooper-Frye procedure describing particlization of an interacting hadron resonance gas. The effects of global baryon number conservation are taken into account using a generalized subensemble acceptance method. The experimental data of the STAR collaboration are consistent at $\sqrt{s_{\mathrm{NN}}}\gtrsim 20$ GeV with simultaneous effects of global baryon number conservation and repulsive interactions in baryon sector, the latter being in line with the behavior of baryon number susceptibilities observed in lattice QCD. The data at lower collision energies show possible indications for sizable attractive interactions among baryons. The data also indicate sizable negative two-particle correlations between antiprotons that are not satisfactorily described by baryon conservation and excluded volume effects. We also discuss differences between cumulants and correlation functions (factorial cumulants) of (anti)proton number distribution, proton versus baryon number fluctuations, and effects of hadronic afterburner.

   ↳ hep-phnucl-exnucl-thPRC(2022)·100 citations
5. 05*

   Nuclear Structure at the Crossroads

   R.J. Furnstahl🇺🇸 · H.-W. Hammer🇩🇪 · A. Schwenk🇩🇪

   Steven Weinberg's seminal papers from 1990-92 initiated the use of effective field theories (EFTs) for nuclei. We summarize progress, priorities, and open questions for nuclear EFT developments based on the 2019 INT program "Nuclear Structure at the Crossroads."

   ↳ nucl-thhep-phnucl-exFew Body Syst.(2021)·16 citations
6. 06*

   Eccentricities, fluctuations and A-dependence of elliptic and triangular flows in heavy-ion collisions

   G.Kh. Eyyubova🇷🇺 · V.L. Korotkikh🇷🇺 · A.M. Snigirev🇷🇺 · E.E. Zabrodin🇳🇴

   A simple geometrical model with event-by-event fluctuations is suggested to study elliptical and triangular eccentricities in the initial state of relativistic heavy-ion collisions. This model describes rather well the ALICE and ATLAS data for Pb+Pb collisions at center-of-mass energy $\sqrt{s_{NN}}=5.02$~TeV per nucleon pair, assuming that the second, $v_2$, and third, $v_3$, harmonics of the anisotropic flow are simply linearly proportional to the eccentricities ${\epsilon }_2$ and ${\epsilon }_3$, respectively. We show that the eccentricity ${\epsilon }_3$ has a pure fluctuation origin and is substantially dependent on the size of the overlap area only, while the eccentricity ${\epsilon }_2$ is mainly related to the average collision geometry. Elliptic flow, therefore, is weakly dependent on the event-by-event fluctuations everywhere except of the very central collisions 0--2%, whereas triangular flow is mostly determined by the fluctuations. The scaling dependence of the magnitude of the flow harmonics on atomic number, $v_n\propto A^{-1/3}$, is predicted for this centrality interval.

   ↳ nucl-thhep-phnucl-exJ.Phys.G(2021)·9 citations
7. 07*

   The unfinished fabric of the three neutrino paradigm

   Francesco Capozzi🇺🇸 · Eleonora Di Valentino🇬🇧 · Eligio Lisi🇮🇹 · Antonio Marrone🇮🇹 · Alessandro Melchiorri🇮🇹 · Antonio Palazzo🇮🇹

   In the current 3nu paradigm, flavor oscillations probe 3 mixing angles (theta_12, theta_23, theta_13), one CP phase delta, and two squared mass differences delta m^2>0 and Delta m^2, where sign(Delta m^2)=+ (-) for normal (inverted) ordering. Absolute nu masses can be probed by the effective m_beta in beta decay, by the total mass Sigma in cosmology and, if neutrinos are Majorana, by another effective m_{beta beta} in 0nu2beta decay. Within an updated global analysis of (non)oscillation data, we constrain these 3nu parameters, both separately and in selected pairs, and highlight the concordance or discordance among different constraints. Five oscillation parameters (delta m^2, Delta m^2, theta_12, theta_23, theta_13) are consistently measured, with an overall accuracy ranging from ~1% for Delta m^2 to ~6% for sin^2(theta_23) (due to its octant ambiguity). We find overall hints for normal ordering (at 2.5 sigma), as well as for theta_23<pi/4 and for sin(delta)<0 (both at 90% C.L.), and discuss some tensions among datasets. Concerning nonoscillation data, we include the recent KATRIN constraints on m_beta, and we combine the latest 76-Ge, 130-Te and 136-Xe bounds on m_{beta beta}, accounting for NME covariances. We also discuss some variants related to CMB anisotropy and lensing data, which may affect cosmological constraints on Sigma and hints on sign(Delta m^2). The default option, including all Planck results, irrespective of the lensing anomaly, sets upper bounds on Sigma at the level of ~10^-1 eV, and further favors normal ordering up to ~3 sigma. An alternative option, that includes recent ACT results + other independent results (from WMAP and selected Planck data) globally consistent with standard lensing, is insensitive to the ordering but prefers Sigma ~(few) x 10^-1 eV, with different implications for m_beta and m_{beta beta} searches. (Abridged)

   ↳ hep-phastro-ph.COhep-exnucl-ex+1PRD(2021)·295 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.