Fri·Aug 19, 2022Friday·August 19, 2022

1. 01*

   Single neutron transfer on 23Ne and its relevance forthepathway ofnucleosynthesis in astrophysical X-ray bursts

   G.Lotay🇬🇧 · J.Henderson🇨🇦 · W.N.Catford🇬🇧 · F.A.Ali🇨🇦 · J.Berean🇨🇦 · N.Bernier🇨🇦 · S.S.Bhattacharjee🇨🇦 · M.Bowry🇨🇦 · R.Caballero-Folch🇨🇦 · B.Davids🇨🇦 · T.E.Drake🇨🇦 · A.B.Garnsworthy🇨🇦 and 23 other authors

   We present new experimental measurements of resonance strengths in the astrophysical 23Al(p, {\gamma})24Si reaction, constraining the pathway of nucleosynthesis beyond 22Mg in X-ray burster scenarios. Specifically, we have performed the first measurement of the (d, p) reaction using a radioactive beam of 23Ne to explore levels in 24Ne, the mirror analog of 24Si. Four strong single-particle states were observed and corresponding neutron spectroscopic factors were extracted with a precision of {\sim}20{\%}. Using these spectroscopic factors, together with mirror state identifications, we have reduced uncertainties in the strength of the key {\ell} = 0 resonance at Er= 157 keV, in the astrophysical 23Al(p, {\gamma}) reaction, by a factor of 4. Our results show that the 22Mg(p, {\gamma})23Al(p, {\gamma}) pathway dominates over the competing 22Mg({\alpha}, p) reaction in all but the most energetic X-ray burster events (T>0.85GK), significantly affecting energy production and the preservation of hydrogen fuel.

   nucl-exPLB(2022)·5 citations
2. 02*

   Isolated photon-jet correlations in Pb-Pb collisions at $\sqrt{s_{\text{NN}}}=5.02$ TeV in ALICE

   Alwina Liu (for the ALICE Collaboration)🇺🇸

   Jets correlated with isolated photons are a promising channel to study jet quenching in heavy-ion collisions, as photons do not interact strongly and therefore constrain the $Q^2$ of the initial hard scattering. We present the isolated photon-jet correlations measured in Pb--Pb collisions at $\sqrt{s_{\text{NN}}}$ = 5.02 TeV by the ALICE collaboration. We study correlations of isolated photons above 20 GeV/$c$ with charged-particle jets above 10 GeV/$c$, reconstructed with the anti-$k_{\text{T}}$ algorithm. The correlations probe the lowest jet $p_{\text{T}}$ range ever measured at LHC energies, and larger modifications due to the QGP are expected in the lower $p_{\text{T}}$ regime.

   nucl-exActa Phys.Polon.Supp.(2023)·2 citations
3. 03*

   The study of key reactions shaping the post main-sequence evolution of massive stars in underground facilities

   F. Ferraro🇮🇹 · G.F. Ciani🇮🇹 · A. Boeltzig🇮🇹 · F. Cavanna🇮🇹 · S. Zavatarelli🇮🇹

   The chemical evolution of the Universe and several phases of the stellar life are regulated by minute nuclear reactions. The key point for each of these reactions is the value of cross sections at the energies at which they take place in stellar environments. Direct cross-section measurements are mainly hampered by the very low counting rate and by cosmic background, nevertheless they have become possible by combining the best experimental techniques with the cosmic silence of an underground laboratory. In the nineties the LUNA (Laboratory for Underground Nuclear Astrophysics) collaboration opened the era of underground nuclear astrophysics installing first a home-made 50 kV and later on, a second 400 kV accelerator under the Gran Sasso mountain in Italy: in 25 years of experimental activity, important reactions responsible for hydrogen burning could have been studied down to the relevant energies thanks to the high current proton and helium beams provided by the machines. The interest to the next and warmer stages of star evolution (i.e. post main sequence, helium and carbon burning) drove a new project based on an ion accelerator in the MV range called LUNA-MV, able to deliver proton, helium and carbon beams. The present contribution is aimed to discuss the state-of-the-art for some selected key processes of post main sequence stellar phases: the 12Cag and the 12C+12C fundamental for helium and carbon burning phases, and 13Can and 22Neag that are relevant to the synthesis of heavy elements in AGB stars. The perspectives opened by an underground MV-facility will be highlighted.

   nucl-exFront.Astron.Space Sci.(2021)·16 citations
4. 04*

   Color coherence effects in the reaction $d(p,2p)n$

   A.B. Larionov🇷🇺

   The hard proton knock-out by the proton from the deuteron at relativistic energies is considered with a focus on the color transparency (CT) effect which influences the initial and final state interactions. The calculations are performed in the framework of the generalized eikonal approximation supplemented by the quantum diffusion model of CT. The main results of the previous calculations [1] at the beam momentum below 20 GeV/c are confirmed, including the dependence of the nuclear transparency on the transverse momentum of the spectator neutron, $p_{st}$, and on the relative azimuthal angle $\varphi$ between proton and neutron: absorption at $p_{st}<0.2$ GeV/c and enhancement at $p_{st}>0.3$ GeV/c due to rescattering on the neutron, the change of $\varphi$-dependence between these two regions, and the enhancement of CT effects with $p_{\mathrm{lab}}$. The study is then generalized to higher beam momenta, up to 75 GeV/c. It is shown that such behavior of the transparency is mainly preserved up to $p_{\mathrm{lab}}\simeq 50$ GeV/c, but changes significantly at higher beam momenta due to the interference of valence quark configurations of small and large sizes. As a result, the transparency at small $p_{st}$ exhibits oscillations as a function of the beam momentum (the nuclear filtering effect). The tensor analyzing power due to the longitudinal polarization of the deuteron is calculated. The event rate at NICA-SPD is estimated.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2023)·7 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.