Fri·Aug 27, 2021Friday·August 27, 2021

1. 01*

   Overview of open heavy-flavour and quarkonia measurements with ALICE

   Andrea Dubla (on behalf of the ALICE Collaboration)🇩🇪

   Heavy-flavour hadrons, i.e. hadrons containing charm or beauty quarks, are effective probes to test perturbative-QCD (pQCD) calculations, to investigate the different hadronisation mechanisms, and to study the quark-gluon plasma (QGP) produced in relativistic heavy-ion collisions at the LHC. Measurements performed in pp and p-Pb collisions have recently revealed unexpected features not in line with the expectations based on previous measurements from ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ and ep collisions, showing that charm fragmentation fractions are not universal. The investigation of initial-state effects such as shadowing in the collision of a proton with a heavy nucleus is also performed. Measurements of open heavy-flavour and quarkonia production in Pb-Pb collisions allow for testing the mechanisms of heavy-quark transport, energy loss, and coalescence effects during the hadronisation in the presence of a QCD medium. In this contribution, the most recent results on open heavy-flavour and quarkonia production in pp, p-Pb, and Pb-Pb collisions obtained by the ALICE Collaboration are discussed.

   nucl-exhep-exEPJ Web Conf.(2022)·0 citations
2. 02*

   Valence quark ratio in the proton

   Zhu-Fang Cui🇨🇳 · Fei Gao🇩🇪 · Daniele Binosi🇮🇹 · Lei Chang🇨🇳 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪

   Beginning with precise data on the ratio of structure functions in deep inelastic scattering (DIS) from ${}^3$He and ${}^3$H, collected on the domain $0.19\le x_B\le 0.83$, where $x_B$ is the Bjorken scaling variable, we employ a robust method for extrapolating such data to arrive at a model-independent result for the $x_B=1$ value of the ratio of neutron and proton structure functions. Combining this with information obtained in analyses of DIS from nuclei, corrected for target-structure dependence, we arrive at a prediction for the proton's valence-quark ratio: ${d_v/u_v|}_{x_B\to 1}=0.230(57)$. Requiring consistency with this result presents a challenge to many descriptions of proton structure.

   ↳ hep-phhep-exhep-latnucl-ex+1Chin.Phys.Lett.(2022)·24 citations
3. 03*

   Deeply Learning Deep Inelastic Scattering Kinematics

   Markus Diefenthaler🇺🇸 · Abdullah Farhat🇺🇸 · Andrii Verbytskyi🇩🇪 · Yuesheng Xu🇺🇸

   We study the use of deep learning techniques to reconstruct the kinematics of the neutral current deep inelastic scattering (DIS) process in electron-proton collisions. In particular, we use simulated data from the ZEUS experiment at the HERA accelerator facility, and train deep neural networks to reconstruct the kinematic variables $Q^2$ and $x$. Our approach is based on the information used in the classical construction methods, the measurements of the scattered lepton, and the hadronic final state in the detector, but is enhanced through correlations and patterns revealed with the simulated data sets. We show that, with the appropriate selection of a training set, the neural networks sufficiently surpass all classical reconstruction methods on most of the kinematic range considered. Rapid access to large samples of simulated data and the ability of neural networks to effectively extract information from large data sets, both suggest that deep learning techniques to reconstruct DIS kinematics can serve as a rigorous method to combine and outperform the classical reconstruction methods.

   ↳ hep-phhep-exnucl-exEPJC(2022)·21 citations
4. 04*

   Neutrinoless double-beta decay from an effective field theory for heavy nuclei

   Catharina Brase🇩🇪 · Javier Menéndez🇪🇸 · Eduardo Antonio Coello Pérez🇺🇸 · Achim Schwenk🇩🇪

   We study neutrinoless double-beta decay in an effective field theory (EFT) for heavy nuclei, which are treated as a spherical core coupled to additional neutrons and/or protons. Since the low-energy constants of the EFT cannot be fitted to data for this unobserved decay, we follow an alternative strategy to constrain these through a correlation with double Gamow-Teller transitions. This correlation was recently found to hold for shell-model calculations, energy-density functionals, and other nuclear structure models. We therefore first calculate the nuclear matrix elements for double Gamow-Teller transitions in the EFT for heavy nuclei. The combination of the EFT uncertainty with the correlation uncertainty enables predictions of nuclear matrix elements for neutrinoless double-beta decay for a broad range of isotopes with quantified uncertainties. Generally the EFT predicts smaller nuclear matrix elements compared to other approaches, but our EFT results are consistent with recent ab initio calculations.

   ↳ nucl-thnucl-exPRC(2022)·25 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.