Mon·Nov 19, 2018Monday·November 19, 2018

1. 01*

   High resolution measurement of tagged two-neutron energy and angle correlations in Cf-252(sf)

   P. F. Schuster · M. J. Marcath · S. Marin · S. D. Clarke🇺🇸 · M. Devlin🇺🇸 · R. C. Haight🇺🇸 · R. Vogt🇺🇸 · P. Talou🇺🇸 · I. Stetcu🇺🇸 · T. Kawano🇺🇸 · J. Randrup🇺🇸 · S. A. Pozzi🇮🇹

   Background: Spontaneous fission events emit prompt neutrons correlated with one another in emission angle and energy. Purpose: We explore the relationship in energy and angle between correlated prompt neutrons emitted from 252Cf spontaneous fission. Methods: Measurements with the Chi-Nu array provide experimental data for coincident neutrons tagged with a fission chamber signal with 10 degree angular resolution and 1 ns timing resolution for time-of-flight energy calculations. The experimental results are compared to simulations produced by the fission event generators CGMF, FREYA, and MCNPX-POLIMI IPOL(1)=1. Results: We find that the measurements and the simulations all exhibit anisotropic neutron emission, though differences exist between fission event generators. Conclusions: This work shows that the dependence of detected neutron energy on the energy of a neutron detected in coincidence, although weak, is non-negligible, indicating that there may be correlations in energy between two neutrons emitted in the same fission event.

   nucl-exPRC(2019)·9 citations
2. 02*

   Soft drop groomed jet angularities at the LHC

   Zhong-Bo Kang🇺🇸 · Kyle Lee🇺🇸 · Xiaohui Liu🇨🇳 · Felix Ringer🇺🇸

   Jet angularities are a class of jet substructure observables where a continuous parameter is introduced in order to interpolate between different classic observables such as the jet mass and jet broadening. We consider jet angularities measured on an inclusive jet sample at the LHC where the soft drop grooming procedure is applied in order to remove soft contaminations from the jets. The soft drop algorithm allows for a precise comparison between theory and data and could be used to extract the QCD strong coupling constant ${\alpha }_s$ from jet substructure data in the future. We develop a framework to realize the resummation of all relevant large logarithms at the next-to-leading logarithmic (NLL) accuracy. To demonstrate that the developed formalism is suitable for the extraction of ${\alpha }_s$, we extend our calculations to next-to-next-to-leading logarithm (NNLL) for the jet mass case. Overall, we find good agreement between our NLL numerical results and Pythia simulations for LHC kinematics and we observe an improved agreement when the NNLL components are included. In addition, we expect that groomed jet angularities will be a useful handle for studying the modification of jets in heavy-ion collisions.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2019)·80 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.