Wed·Aug 4, 2021Wednesday·August 4, 2021

1. 01*

   Impact of ${}^7$Be breakup on ${}^7$Li(p,n) Neutron Spectrum

   Midhun C.V · M.M Musthafa · S.V Suryanarayana · T. Santhosh · A. Baishya · P. Patil · A Pal · P.C Rout · S Santra · R. Kujur · Antony Joseph · Shaima A🇯🇵 and 8 other authors

   The formation of continuum neutron distribution in ${}^7$Li(p,n) has been identified as due to the coupling of the ${}^7$Be breakup levels to the final state of the reaction. The continuum neutron spectra produced by ${}^7$Li(p,n) reaction has been estimated by measuring the double differential cross sections for continuum and resonant breakup of ${}^7$Be, through ${}^7$Li(p,n)${}^7$Be${}^{\ast }$ reaction at 21 MeV of proton energy. The breakup contributions from continuum and $5/2^{-}$, $7/2^{-}$ states of ${}^7$Be have been identified. The measured double differential cross sections have been reproduced through CDCC-CRC calculations. The cross sections were projected to neutron spectrum using Monte-Carlo approach and validated using experimentally measured ${}^3$He gated neutron spectra. ${}^7$Li(p,n) neutron spectrum at 20 MeV incident proton energy measured by McNaughton. et al. has been reproduced by adapting estimated model parameters for the reaction.

   nucl-exnucl-thPRC(2021)·10 citations
2. 02*

   Isomeric Ratio of the ${}^{181}\mathrm{Ta}(\gamma ,3n{)}^{178m,\mathrm{g}}\mathrm{Ta}$ Reaction Products at Energy $E_{\gamma \max }$ up to 95 MeV

   O.S. Deiev🇺🇦 · I.S. Timchenko🇺🇦 · S.N. Olejnik🇺🇦 · V.A. Kushnir🇺🇦 · V.V. Mytrochenko🇺🇦 · S.A. Perezhogin🇺🇦

   The photoneutron reaction ${}^{181}\mathrm{Ta}(\gamma ,3n{)}^{178m,\mathrm{g}}\mathrm{Ta}$ was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40. The measurements were performed using the residual $\gamma$-activity method. The bremsstrahlung flux-averaged cross-sections $⟨\sigma (E_{\gamma \max })⟩$, $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{m}}$, $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{g}}$ and the isomeric ratio of the reaction products $d(E_{\gamma \max })$ have been measured. Theoretical values of averaged cross-sections and isomeric ratio were calculated using partial cross-sections from the TALYS1.95 code for different level density models $LD$ 1-6. The obtained experimental $d(E_{\gamma \max })$ agree with the literature data, but differ from the theoretical values in absolute magnitude and the behavior of the energy dependence. A comparison of the found averaged cross-sections with the calculated ones showed the best agreement for the case of the $LD$ 5 model.

   nucl-exhep-exCPC(2022)·10 citations
3. 03*

   Classical and Machine Learning Methods for Event Reconstruction in NeuLAND

   Jan Mayer🇨🇦 · Konstanze Boretzky · Christiaan Douma · Elena Hoemann · Andreas Zilges

   NeuLAND, the New Large Area Neutron Detector, is a key component to investigate the origin of matter in the universe with experimental nuclear physics. It is a core component of the Reactions with Relativistic Radioactive Beams setup at the Facility for Antiproton and Ion Research, Germany. Neutrons emitted from these reactions create a wide range of patterns in NeuLAND. From these patterns, the number of neutrons (multiplicity) and their first interaction points must be reconstructed to determine the neutrons' four-momenta. In this paper, we detail the challenges involved in this reconstruction and present a range of possible solutions. Scikit-Learn classification models and simple Keras-based neural networks were trained on a wide range of input-scaler combinations and compared to classical models. While the improvement in multiplicity reconstruction is limited due to the overlap between features, the machine learning methods achieve a significantly better first interaction point selection, which directly improves the resolution of physical quantities.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2021)·7 citations
4. 04*

   Extending Precision Perturbative QCD with Track Functions

   Yibei Li🇨🇳 · Ian Moult🇺🇸 · Solange Schrijnder van Velzen🇳🇱 · Wouter J. Waalewijn🇳🇱 · Hua Xing Zhu🇨🇳

   Collider experiments often exploit information about the quantum numbers of final state hadrons to maximize their sensitivity, with applications ranging from the use of tracking information (electric charge) for precision jet substructure measurements, to flavor tagging for nucleon structure studies. For such measurements, perturbative calculations in terms of quarks and gluons are insufficient, and non-perturbative track functions describing the energy fraction of a quark or gluon converted into a subset of hadrons (e.g., charged hadrons) must be incorporated. Unlike fragmentation functions, track functions describe correlations between hadrons and therefore satisfy complicated non-linear evolution equations whose structure has so far eluded calculation beyond the leading order. In this Letter, we develop an understanding of track functions and their interplay with energy flow observables beyond the leading order, allowing them to be used in state-of-the-art perturbative calculations for the first time. We identify a shift symmetry in the evolution of their moments that fixes their structure, and we explicitly compute the evolution of the first three moments at next-to-leading order, allowing for the description of up to three-point energy correlations. We then calculate the two-point energy correlator on charged particles at $O({\alpha }_s^2)$, illustrating explicitly that infrared singularities in perturbation theory are absorbed by moments of the track functions and also highlighting how these moments seamlessly interplay with modern techniques for perturbative calculations. Our results extend the boundaries of traditional perturbative QCD, enabling precision perturbative predictions for energy flow observables sensitive to the quantum numbers of hadronic states.

   ↳ hep-phhep-exnucl-exnucl-thPRL(2022)·93 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.