Tue·Aug 23, 2022Tuesday·August 23, 2022

1. 01*

   Open and hidden heavy-flavor production in small systems with ALICE

   Sebastien Perrin (for the ALICE Collaboration)🇫🇷

   Measurements of quarkonia (heavy quark and antiquark bound states) and open-heavy flavour hadrons in hadronic collisions provide a unique testing ground for understanding quantum chromodynamics (QCD). Although recently there was significant progress, our understanding of hadronic collisions has been challenged by the observation of intriguing effects in high-multiplicity proton-proton (pp) and p-Pb collisions, such as collective phenomena. The excellent particle identification, track and decay-vertex reconstruction capabilities of the ALICE experiment are exploited to measure quarkonia as well as open-heavy flavour hadron production at midrapidity while quarkonium measurements are inclusive at forward rapidity. In this contribution, the first measurements of the elliptic flow ($v_2$) of $J/\psi$ in high multiplicity pp collisions is shown. New measurements of quarkonium and open-beauty hadron production in pp and p-Pb collisions are presented, such as the first measurement of the non-prompt ${\text{D}}^{\ast +}$ polarization in pp collisions at $\sqrt{s}=13$ TeV. The comparison of results with available models is also discussed.

   nucl-exhep-exActa Phys.Polon.Supp.(2023)·0 citations
2. 02*

   Recent Progress in Two-proton Radioactivity

   L. Zhou🇨🇳 · S. M. Wang · D. Q. Fang🇨🇳 · Y. G. Ma🇨🇳

   During the last few decades, rare isotope beam facilities have provided unique data for studying the properties of nuclides located far from the beta-stability line. Such nuclei are often accompanied by exotic structures and radioactive modes, which represent the forefront of nuclear research. Among them, two-proton (2p) radioactivity is a rare decay mode found in a few highly proton-rich isotopes. The 2p decay lifetimes and properties of emitted protons hold invaluable information regarding the nuclear structures in the presence of a low-lying proton continuum; as such, they have attracted considerable research attention. In this review, we present some of the recent experimental and theoretical progress regarding the 2p decay, including technical innovations for measuring nucleon--nucleon correlations and developments in the models that connect their structural aspects with their decay properties. This impressive progress should play a significant role in elucidating the mechanism of these exotic decays, probing the corresponding components inside nuclei, and providing deep insights into the open quantum nature of dripline systems.

   nucl-exnucl-thNucl.Sci.Tech.(2022)·57 citations
3. 03*

   Indirect measurement of the $(n,\gamma {)}^{127}$Sb cross section

   Francesco Pogliano🇳🇴 · Ann-Cecilie Larsen🇳🇴 · Frank Leonel Bello Garrote🇳🇴 · Marianne Møller Bjørøen · Tomas Kvalheim Eriksen🇦🇺 · Dorthea Gjestvang · Andreas Görgen🇳🇴 · Magne Guttormsen🇳🇴 · Kevin Ching Wei Li🇿🇦 · Maria Markova🇳🇴 · Eric Francis Matthews · Wanja Paulsen and 5 other authors

   Nuclei in the ${}^{135}$I region have been identified as being a possible bottleneck for the \textit{i} process. Here we present an indirect measurement for the Maxwellian-averaged cross section of ${}^{126}\text{Sb}(n,\gamma )$. The nuclear level density and the $\gamma$-ray strength function of ${}^{127}$Sb have been extracted from ${}^{124}$Sn$(\alpha ,p\gamma {)}^{127}$Sb data using the Oslo method. The level density in the low-excitation-energy region agrees well with known discrete levels, and the higher-excitation-energy region follows an exponential curve compatible with the constant-temperature model. The strength function between $E_{\gamma }\approx$ 1.5-8.0 MeV presents several features, such as an upbend and a possibly double-peaked pygmy-like structure. None of the theoretical models included in the nuclear reaction code TALYS seem to reproduce the experimental data. The Maxwellian-averaged cross section for the ${}^{126}$Sb$(n,\gamma {)}^{127}$Sb reaction has been experimentally constrained by using our level-density and strength-function data as input to TALYS. We observe a good agreement with the JINA REACLIB, TENDL, and BRUSLIB libraries, while the ENDF/B-VIII.0 library predicts a significantly higher rate than our results.

   nucl-exPRC(2022)·7 citations
4. 04*

   Electromagnetic probes of the Quark-Gluon Plasma

   Gojko Vujanovic🇺🇸

   The penetrating nature of electromagnetic probes makes them an ideal candidate to study properties of the Quark-Gluon Plasma (QGP). A selection of recent developments in the theory and phenomenology of electromagnetic probes is discussed, with an emphasis given towards how these probes can be used to constrain QGP trapnsport coefficients. A Bayesian treatment of electromagnetic radiation, similar to the one of soft hadronic observables and jets, is suggested as a path towards imposing more stringent constraints on various transport coefficients of the QCD medium.

   ↳ hep-phnucl-exnucl-thActa Phys.Polon.Supp.(2023)·2 citations
5. 05*

   Determination of asymptotic normalization coefficients for the channel ${}^{16}$O$\to \alpha {+}^{12}$C. Excited state ${}^{16}$O($0^{+};6.05$ MeV)

   L. D. Blokhintsev · A. S. Kadyrov · A. M. Mukhamedzhanov🇺🇸 · D. A. Savin

   Asymptotic normalization coefficients (ANC) determine the overall normalization of cross sections of peripheral radiative capture reactions. In the present paper, we treat the ANC $C$ for the virtual decay ${}^{16}$O$(0^{+};6.05$ MeV)$\to \alpha {+}^{12}$C(g.s.), the known values of which are characterized by a large spread $(0.29-1.65)\times 10^3$ fm${}^{-1/2}$. The ANC $C$ is found by analytic continuation in the energy of the ${\alpha }^{12}$C $s$-wave scattering amplitude, known from the phase-shift analysis of experimental data, to the pole corresponding to the ${}^{16}$O bound state and lying in the unphysical region of negative energies. To determine $C$, two different methods of analytic continuation are used. In the first method, the scattering data are approximated by the sum of polynomials in energy in the physical region and then extrapolated to the pole. The best way of extrapolation is chosen on the basis of the exactly solvable model. Within the second approach, the ANC $C$ is found by solving the Schrödinger equation for the two-body ${\alpha }^{12}$C potential, the parameters of which are selected from the requirement of the best description of the phase-shift analysis data at a fixed experimental binding energy of ${}^{16}$O$(0^{+};6.05$ MeV) in the $\alpha {+}^{12}$C channel. The values of the ANC $C$ obtained within these two methods lie in the interval (886--1139) fm${}^{-1/2}$.

   ↳ nucl-thastro-ph.SRnucl-exEPJA(2022)·9 citations
6. 06*

   Hadro-chemistry effects on charm decayed leptons in heavy-ion collisions

   Kai Lu🇨🇳 · Min He🇨🇳

   Charm-hadrons possess versatile hadro-chemistry as characterized by various transverse-momentum-dependent ratios between their different species. In particular, the charm hadro-chemistry may be modified in relativistic heavy-ion collisions with respect to proton-proton collisions at the same energy, as caused by novel diffusion and hadronization mechanisms of charm quarks in the environment of the created quark-gluon plasma (QGP) in the former. Inspired by recent measurements of leptons from charm-hadron decays (separated from bottom decays) in Pb-Pb and Au-Au collisions, we investigate the effects of the charm hadro-chemistry on the leptonic observables. We find that full consideration of charm hadro-chemistry in both proton-proton and heavy-ion collisions causes only mild change of charm-leptons' suppression factor with respect to previous calculations hadronizing charm quarks into $D$ mesons only, whereas the resulting change (increase) in the charm-leptons' elliptic flow turns out to be more pronounced as a consequence of the larger collectivity of ${\Lambda }_c$ baryons than $D$ mesons.

   ↳ nucl-thhep-phnucl-exPRC(2022)·0 citations
7. 07*

   High-order isospin-dependent surface tension contribution to the fourth-order symmetry energy of finite nuclei

   Bao-Jun Cai🇨🇳 · Rui Wang · Zhen Zhang🇨🇳 · Lie-Wen Chen🇨🇳

   The relation between the fourth-order symmetry energy $E_{\mathrm{sym},4}({\rho }_0)$ of nuclear matter at saturation density ${\rho }_0$ and its counterpart $a_{\mathrm{sym},4}(A)$ of finite nuclei in a semiempirical nuclear mass formula is revisited by considering the high-order isospin-dependent surface tension contribution to the latter. We derive the full expression of $a_{\mathrm{sym},4}(A)$, which includes explicitly the high-order isospin-dependent surface tension effects, and find that the value of $E_{\mathrm{sym},4}({\rho }_0)$ cannot be extracted from the measured $a_{\mathrm{sym},4}(A)$ before the high-order surface tension is well constrained. Our results imply that a large $a_{\mathrm{sym},4}(A)$ value of several MeVs obtained from analyzing nuclear masses can nicely agree with the empirical constraint of $E_{\mathrm{sym},4}({\rho }_0)\lesssim 2$ MeV from mean-field models and does not necessarily lead to a large $E_{\mathrm{sym},4}({\rho }_0)$ value of $\approx 20$ MeV obtained previously without considering the high-order surface tension. Furthermore, we also give the expression for the sixth-order symmetry energy $a_{\mathrm{sym},6}(A)$ of finite nuclei, which involves more nuclear matter bulk parameters and the higher-order isospin-dependent surface tension.

   ↳ nucl-thastro-ph.HEnucl-exPRC(2022)·4 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.