Mon·Dec 10, 2018Monday·December 10, 2018

1. 01*

   Near-threshold ${\pi }^{-}$ photoproduction on the deuteron

   B. Strandberg🇬🇧 · K. G. Fissum🇸🇪 · J. R. M. Annand🇬🇧 · W. J. Briscoe🇺🇸 · J. Brudvik🇸🇪 · F. Cividini🇩🇪 · L. Clark · E. J. Downie🇺🇸 · K. England🇺🇸 · G. Feldman🇺🇸 · D. I. Glazier🇬🇧 · K. Hamilton and 20 other authors

   The first experimental investigation of the near-threshold cross section for incoherent ${\pi }^{-}$ photoproduction on the deuteron $\gamma$ d -> ${\pi }^{-}$ pp is presented. The experimental technique involved detection of the ~131 MeV gamma ray resulting from the radiative capture of photoproduced ${\pi }^{-}$ in the target. The total cross section has been measured using an unpolarized tagged-photon beam, a liquid-deuterium target, and three very large NaI(Tl) spectrometers. The data are compared to theoretical models that give insight into the elementary reaction $\gamma$ n -> ${\pi }^{-}$ p and pion-nucleon and nucleon-nucleon final-state interactions.

   nucl-exPRC(2020)·17 citations
2. 02*

   Initial transverse-momentum broadening of Breit-Wheeler process in relativistic heavy-ion collisions

   Wangmei Zha🇨🇳 · James Daniel Brandenburg🇨🇳 · Zebo Tang🇨🇳 · Zhangbu Xu🇺🇸

   We calculate the cross section and transverse-momentum ($P_{\perp }$) distribution of the Breit-Wheeler process in relativistic heavy-ion collisions and their dependence on collision impact parameter ($b$). To accomplish this, the Equivalent Photon Approximation (EPA) was generalized in a more differential way compared to the approach traditionally used for inclusive collisions. In addition, a lowest-order QED calculation with straightline assumption was performed as a standard baseline for comparison. The cross section as a function of $b$ is consistent with previous calculations using the equivalent one-photon distribution function. Most importantly, the $P_{\perp }$ shape from this model is strongly dependent on impact parameter and can quantitatively explain the $P_{\perp }$ broadening observed recently by RHIC and LHC experiments. This broadening effect from the initial QED field strength should be considered in studying possible trapped magnetic field and multiple scattering in a Quark-Gluon Plasma (QGP). The impact-parameter sensitive observable also provides a controllable tool for studying extreme electromagnetic fields.

   ↳ nucl-thnucl-exPLB(2020)·99 citations
3. 03*

   Suppression of Cosmic Muon Spallation Backgrounds in Liquid Scintillator Detectors Using Convolutional Neural Networks

   A. Li🇺🇸 · A. Elagin🇺🇸 · S. Fraker🇺🇸 · C. Grant🇺🇸 · L. Winslow🇺🇸

   Cosmic muon spallation backgrounds are ubiquitous in low-background experiments. For liquid scintillator-based experiments searching for neutrinoless double-beta decay, the spallation product ${}^{10}$C is an important background in the region of interest between 2-3 MeV and determines the depth requirement for the experiment. We have developed an algorithm based on a convolutional neural network that uses the temporal and spatial correlations in light emissions to identify ${}^{10}$C background events. With a typical kiloton-scale detector configuration like the KamLAND detector, we find that the algorithm is capable of identifying 61.6% of the ${}^{10}$C at 90% signal acceptance. A detector with perfect light collection could identify 98.2% at 90% signal acceptance. The algorithm is independent of vertex and energy reconstruction, so it is complementary to current methods and can be expanded to other background sources.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2019)·24 citations
4. 04*

   The MORA project

   P. Delahaye🇫🇷 · E. Liénard🇫🇷 · I. Moore🇫🇮 · M. Benali🇫🇷 · M. L. Bissell🇬🇧 · L. Canete🇫🇮 · T. Eronen🇫🇮 · A. Falkowski🇫🇷 · X. Fléchard🇫🇷 · M. Gonzalez-Alonso🇨🇭 · W. Gins🇧🇪 · R. P. De Groote🇫🇮 and 16 other authors

   The MORA (Matter's Origin from the RadioActivity of trapped and oriented ions) project aims at measuring with unprecedented precision the D correlation in the nuclear beta decay of trapped and oriented ions. The D correlation offers the possibility to search for new CP-violating interactions, complementary to searches done at the LHC and with Electric Dipole Moments. Technically, MORA uses an innovative in-trap orientation method which combines the high trapping efficiency of a transparent Paul trap with laser orientation techniques. The trapping, detection, and laser setups are under development, for first tests at the Accelerator laboratory, JYFL, in the coming years.

   ↳ physics.ins-detnucl-exHyperfine Interact.(2019)·15 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.