Wed·Nov 27, 2019Wednesday·November 27, 2019

1. 01*

   The GlueX Experiment: Recent Results and Future Plans

   Jonathan Zarling🇺🇸

   The GlueX experiment, located in experimental Hall D of Jefferson Lab, seeks to map the spectrum of light mesons in search of exotic hybrid mesons, a predicted class of hadronic states with explicit gluonic degrees of freedom. GlueX is a photoproduction experiment utilizing a linearly polarized photon beam at $E_{\gamma }=$ 8-9 GeV and a large acceptance spectrometer. The experiment has already collected orders of magnitude more data than previous experiments at similar energies. We show results on asymmetry measurements in the production of pseudoscalars mesons, which refine our understanding of production mechanisms in photoproduction at our energies. We also present results on $J/\psi$ photoproduction, which provides model constraints on heavy quark photoproduction and the ability to search for s-channel production of pentaquark candidate $P_c^{+}$ states.

   nucl-exJPS Conf.Proc.(2019)·3 citations
2. 02*

   Prospects of nuclear clustering studies via dissociation of relativistic nuclei in nuclear track emulsion

   D A Artemenkov🇷🇺 · V Bradnova🇷🇺 · E Firu🇷🇴 · M Haiduc🇷🇴 · N K Kornegrutsa · A I Malakhov🇷🇺 · E Mitsova · A Neagu🇷🇴 · N G Peresadko · V V Rusakova🇷🇺 · R Stanoeva🇧🇬 · A A Zaitsev🇷🇺 · I G Zarubina🇷🇺 · P I Zarubin🇷🇺

   Status and prospects of nuclear clustering studies by dissociation of relativistic nuclei in nuclear track emulsion are presented. The unstable ${}^8$Be and ${}^9$B nuclei are identified in dissociation of the isotopes ${}^9$Be, ${}^{10}$B, ${}^{10}$C and ${}^{11}$C, and the Hoyle state in the cases ${}^{12}$C and ${}^{16}$O. On this ground searching for the Hoyle state and more complex $\alpha$-particle states in the dissociation of the heavier nuclei is suggested. A detailed study of a low-density baryonic matter arising in dissociation of the heaviest nuclei is forthcoming long-term problem. An analysis of nuclear fragmentation induced by relativistic muons is proposed to examine the mechanism dissociation.

   nucl-exJ.Phys.Conf.Ser.(2020)·0 citations
3. 03*

   Exclusive ${\pi }^{+}$ electroproduction off the proton from low to high -t

   S. Basnet🇨🇦 · G.M. Huber🇨🇦 · W.B. Li🇺🇸 · H.P. Blok🇳🇱 · D. Gaskell🇺🇸 · T. Horn🇺🇸 · K. Aniol🇺🇸 · J. Arrington🇺🇸 · E.J. Beise🇺🇸 · W. Boeglin🇺🇸 · E.J. Brash🇺🇸 · H. Breuer🇺🇸 and 40 other authors

   Background: Measurements of exclusive meson production are a useful tool in the study of hadronic structure. In particular, one can discern the relevant degrees of freedom at different distance scales through these studies. Purpose: To study the transition between non-perturbative and perturbative Quantum Chromodyanmics as the square of four momentum transfer to the struck proton, -t, is increased. Method: Cross sections for the ${}^1$H(e,e'${\pi }^{+}$)n reaction were measured over the -t range of 0.272 to 2.127 GeV${}^2$ with limited azimuthal coverage at fixed beam energy of 4.709 GeV, Q${}^2$ of 2.4 GeV${}^2$ and W of 2.0 GeV at the Thomas Jefferson National Accelerator Facility (JLab) Hall C. Results: The -t dependence of the measured ${\pi }^{+}$ electroproduction cross section generally agrees with prior data from JLab Halls B and C. The data are consistent with a Regge amplitude based theoretical model, but show poor agreement with a Generalized Parton Distribution (GPD) based model. Conclusion: The agreement of cross sections with prior data implies small contribution from the interference terms, and the confirmation of the change in t-slopes between the low and high -t regions previously observed in photoproduction indicates the changing nature of the electroproduction reaction in our kinematic regime.

   nucl-exhep-exPRC(2019)·3 citations
4. 04*

   The eikonal model of reactions involving exotic nuclei; Roy Glauber's legacy in today's nuclear physics

   Pierre Capel🇩🇪

   In this contribution, the eikonal approximation developed by Roy Glauber to describe high-energy quantum collisions is presented. This approximation has been-and still is-extensively used to analyse reaction measurements performed to study the structure of nuclei far from stability. This presentation focuses more particularly on the application of the eikonal approximation to the study of halo nuclei in modern nuclear physics. To emphasise Roy Glauber's legacy in today's nuclear physics, recent extensions of this model are reviewed.

   ↳ nucl-thnucl-exphysics.hist-phSciPost Phys.Proc.(2020)·4 citations
5. 05*

   Sub-threshold $J/\psi$ and ${\rm Y}$ Production in $\gamma A$ Collisions

   Yoshitaka Hatta (BNL)🇺🇸 · Mark Strikman (PSU)🇺🇸 · Ji Xu (SJTU)🇨🇳 · Feng Yuan (LBNL)🇺🇸

   We study sub-threshold heavy quarkonium ($J/\psi$ and ${\rm Y}$) photo-productions in $\gamma A$ collisions as an independent test of the universality of the nucleon-nucleon short range correlation (SRC) in nuclear scattering processes. Just below the $\gamma p$ threshold, the cross section is dominated by the mean field contribution of nucleons inside the nucleus. The SRC contributions start to dominate at lower photon energies, depending on the fraction of the SRC pairs in the target nucleus. We give an estimate of the cross sections in the sub-threshold region both for $J/\psi$ and ${\rm Y}$. This may be helpful for future measurements at JLab as well as at the Electron-Ion Collider in the U.S., and especially in China.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2020)·32 citations
6. 06*

   DeepRICH: Learning Deeply Cherenkov Detectors

   Cristiano Fanelli🇺🇸 · Jary Pomponi🇮🇹

   Imaging Cherenkov detectors are largely used for particle identification (PID) in nuclear and particle physics experiments, where developing fast reconstruction algorithms is becoming of paramount importance to allow for near real time calibration and data quality control, as well as to speed up offline analysis of large amount of data. In this paper we present DeepRICH, a novel deep learning algorithm for fast reconstruction which can be applied to different imaging Cherenkov detectors. The core of our architecture is a generative model which leverages on a custom Variational Auto-encoder (VAE) combined to Maximum Mean Discrepancy (MMD), with a Convolutional Neural Network (CNN) extracting features from the space of the latent variables for classification. A thorough comparison with the simulation/reconstruction package FastDIRC is discussed in the text. DeepRICH has the advantage to bypass low-level details needed to build a likelihood, allowing for a sensitive improvement in computation time at potentially the same reconstruction performance of other established reconstruction algorithms. In the conclusions, we address the implications and potentialities of this work, discussing possible future extensions and generalization.

   ↳ physics.data-ancs.LGhep-exnucl-ex+1Mach.Learn.Sci.Tech.·27 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.