Fri·Jul 29, 2022Friday·July 29, 2022

1. 01*

   Charm production: constraints to transport models and charm diffusion coefficient with ALICE

   Luuk Vermunt (for the ALICE Collaboration)🇩🇪

   In this contribution, the nuclear modification factor and azimuthal anisotropy of prompt charm mesons and baryons in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV by the ALICE Collaboration are presented. Heavy quarks are a very suitable probe to investigate the quark-gluon plasma (QGP) produced in heavy-ion collisions, since they are mainly produced in hard-scattering processes and hence in shorter timescales compared to the QGP. Measurements of charm-hadron production in nucleus-nucleus collisions are therefore useful to study the properties of the in-medium charm-quark energy loss via the comparison with theoretical models. Models describing the heavy-flavour transport and energy loss in a hydrodynamically expanding QGP require also a precise modelling of the in-medium hadronisation of heavy quarks, which is investigated via the measurement of prompt ${\mathrm{D}}_{\mathrm{s}}^{+}$ mesons and ${\Lambda }_{\mathrm{c}}^{+}$ baryons.

   nucl-exActa Phys.Polon.Supp.(2023)·1 citation
2. 02*

   Measurements and computational analysis on the natural decay of ${}^{176}$Lu

   F. G. A. Quarati · G. Bollen🇺🇸 · P. Dorenbos · M. Eibach🇩🇪 · K. Gulyuz🇺🇸 · A. Hamaker🇺🇸 · C. Izzo🇨🇦 · D. K. Keblbeck🇺🇸 · X. Mougeot🇫🇷 · D. Puentes🇺🇸 · M. Redshaw🇺🇸 · R. Ringle🇺🇸 and 3 other authors

   Mainly because of its long half-life and despite its scientific relevance, spectroscopic measurements of ${}^{176}$Lu forbidden $\beta$-decays are very limited and lack formulation of shape factors. A direct precise measurement of its $Q$ value is also presently unreported. In addition, the description of forbidden decays provides interesting challenges for nuclear theory. The comparison of precise experimental results with theoretical calculations for these decays can help to test underlying models and can aid the interpretation of data from other experiments.

   nucl-exhep-ex3 citations
3. 03*

   Contact interaction analysis of octet baryon axialvector and pseudoscalar form factors

   Peng Cheng🇨🇳 · Fernando E. Serna🇧🇷 · Zhao-Qian Yao🇨🇳 · Chen Chen🇨🇳 · Zhu-Fang Cui🇨🇳 · Craig D. Roberts🇨🇳

   Octet baryon axial, induced pseudoscalar, and pseudoscalar form factors are computed using a symmetry-preserving treatment of a vector$\times$vector contact interaction (SCI), thereby unifying them with an array of other baryon properties and analogous treatments of semileptonic decays of pseudoscalar mesons. The baryons are treated as quark--plus--interacting-diquark bound states, whose structure is obtained by solving a Poincaré-covariant Faddeev equation. The approach is marked by algebraic simplicity, involves no free parameters, and since it is symmetry preserving, all consequences of partial conservation of the axial current are manifest. It is found that SCI results are consistent with only small violations of SU$(3)$-flavour symmetry, an outcome which may be understood as a dynamical consequence of emergent hadron mass. The spin-flavour structure of the Poincaré-covariant baryon wave functions is expressed in the presence of both flavour-antitriplet scalar diquarks and flavour-sextet axialvector diquarks and plays a key role in determining all form factors. Considering neutral axial currents, SCI predictions for the flavour separation of octet baryon axial charges and, therefrom, values for the associated SU$(3)$ singlet, triplet, and octet axial charges are obtained. The results indicate that at the hadron scale, ${\zeta }_{\mathcal{H}}$, valence degrees-of-freedom carry roughly 50% of an octet baryon's total spin. Since there are no other degrees-of-freedom at ${\zeta }_{\mathcal{H}}$, the remainder may be associated with quark+diquark orbital angular momentum.

   ↳ hep-phhep-exhep-latnucl-ex+1PRD(2022)·26 citations
4. 04*

   Non-equilibrium components in very low transverse momentum region in high-energy nuclear collisions

   Yuuka Kanakubo🇯🇵 · Yasuki Tachibana🇯🇵 · Tetsufumi Hirano🇯🇵

   We analyze Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV with a novel framework based on the dynamical core--corona picture that describes particle productions from both equilibrium and non-equilibrium components. We remark the possibility of the contribution from non-equilibrium components at very low transverse momentum ($p_T$) region and show that such contributions significantly affect $p_T$-integrated four-particle cumulants. These results strongly suggest the necessity of non-equilibrium components when one extracts properties of the quark-gluon plasma from experimental data using sophisticated dynamical models based on relativistic hydrodynamics.

   ↳ nucl-thhep-phnucl-exPRC(2022)·14 citations
5. 05*

   Final-state interactions and spin structure in $E1$ breakup of ${}^{1}1$Li in Halo EFT

   Matthias Göbel🇩🇪 · Bijaya Acharya🇺🇸 · Hans-Werner Hammer🇩🇪 · Daniel R. Phillips🇺🇸

   We calculate the $E1$ breakup of the $2n$ halo nucleus ${}^{11}$Li in Halo Effective Field Theory (Halo EFT) at leading order. In Halo EFT, ${}^{11}$Li is treated as a three-body system of a ${}^9$Li core and two neutrons. We present a detailed investigation of final-state interactions (FSI) in the neutron-neutron $(nn)$ and neutron-core $(nc)$ channels. We employ Moller operators to formulate an expansion scheme that satisfies the non-energy-weighted cluster sum rule and successively includes higher-order terms in the multiple-scattering series for the FSI. Computing the $E1$ strength up to third order in this scheme, we observe apparent convergence and good agreement with experiment. The neutron-neutron FSI is by far the most important contribution and largely determines the maximum value of the $E1$ distribution. However, inclusion of $nc$ FSI does shift the peak position to slightly lower energies. Moreover, we investigate the sensitivity of the $E1$ response to the spin structure of the neutron-${}^9$Li interaction. We contrast results for an interaction that is the same in the spin-1 and spin-2 channels with one that is only operative in the spin-2 channel, and find that good agreement with experimental data is only obtained if the interaction is present in both spin channels. The latter case is shown to be equivalent to a calculation in which the spin of ${}^9$Li is neglected.

   ↳ nucl-thnucl-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.