Mon·Mar 4, 2024Monday·March 4, 2024

1. 01*

   Five-dimensional collective Hamiltonian with improved inertial functions

   Kouhei Washiyama · Nobuo Hinohara🇯🇵 · Takashi Nakatsukasa🇯🇵

   Background: To describe shape fluctuations associated with large-amplitude collective motion in the quadrupole degrees of freedom, the five-dimensional collective Hamiltonian (5DCH) has been widely used. The inertial functions in the 5DCH are microscopically calculated with the energy density functional (EDF) theory employing the cranking formula. However, since the cranking formula ignores dynamical residual effects, it is known to fail to reproduce the correct inertial functions, for instance, the total mass for the translational motion. Purpose: We aim to resolve problems of the insufficient description of the inertial functions in the 5DCH. We provide a practical method to include the dynamical residual effects in the inertial functions that depend on the quadrupole deformation parameters $\beta$ and $\gamma$. Methods: We use the local quasiparticle random-phase approximation (LQRPA) based on the constrained Hartree-Fock-Bogoliubov states in the $\beta$--$\gamma$ plane with the Skyrme EDF. The finite-amplitude method is used for efficient computations of the LQRPA. Results: The inertial functions evaluated with the LQRPA significantly increase from the ones with the cranking formula due to the dynamical residual effects. This increase also shows a strong $\beta$--$\gamma$ dependence. We show an application of the present method to a transitional nucleus ${}^{110}$Pd. The low-lying positive-parity spectra are well reproduced with the LQRPA inertial functions. Conclusions: We clarify the importance of the dynamical residual effects in the inertial functions of the 5DCH for the description of the low-lying spectra. The 5DCH with the improved inertial functions provides a reliable and efficient description of low-lying spectra in nuclei associated with the quadrupole shape fluctuation.

   ↳ nucl-thnucl-exPRC(2024)·6 citations
2. 02*

   A Light-Front Model for the Transition Distribution Amplitudes for Backward Timelike Compton Scattering

   B. Pasquini🇮🇹 · A. Schiavi🇮🇹

   To access information on the internal structure of the nucleon, data from a variety of scattering experiments can be analyzed, in regimes where the information factorizes from an otherwise known scattering amplitude. A recent development, promising new insight, is the study of exclusive reactions in the backward kinematical region, where the information can be encoded in Transition Distribution Amplitudes (TDAs). We model the photon-to-nucleon TDAs, entering the factorized description of backward Timelike Compton Scattering, using techniques of light-front dynamics to integrate information from a quark model for the photon and the nucleon. We include the results of numerical predictions that could inform further experiments at Jefferson Lab and the future Electron--Ion Collider.

   ↳ hep-phnucl-exnucl-thPRD(2024)·4 citations
3. 03*

   J/psi-pair production at NLL in TMD factorisation at the LHC

   Alice Colpani Serri🇵🇱 · Jelle Bor🇳🇱 · Daniel Boer🇳🇱 · Jean-Philippe Lansberg🇫🇷

   J/psi-pair production at the LHC is currently one of the few tools available to probe gluon transverse momentum distributions (TMDs). In this context, data from LHCb in the collider mode have the potential to probe the evolution of the unpolarised-gluon TMDs and to measure the distribution of the linearly-polarised gluon in unpolarised protons for the first time. In this proceedings contribution, improved predictions obtained for the LHC (at sqrt(s) = 13 TeV) up to next-to-leading logarithm (NLL) in TMD factorisation are presented. We show the obtained predictions of transverse-momentum distributions at different invariant masses and rapidities computed in the LHCb acceptance along with PDF uncertainty. We predict the azimuthal modulations of the cross section that arise from linearly-polarised gluons.

   ↳ hep-phhep-exnucl-exnucl-thPoS(2024)·2 citations
4. 04*

   Nonperturbative Collins-Soper Kernel from Chiral Quarks with Physical Masses

   Dennis Bollweg🇺🇸 · Xiang Gao🇺🇸 · Swagato Mukherjee🇺🇸 · Yong Zhao🇺🇸

   We present a lattice QCD calculation of the rapidity anomalous dimension of quark transverse-momentum-dependent distributions, i.e., the Collins-Soper (CS) kernel, up to transverse separations of about 1 fm. This unitary lattice calculation is conducted, for the first time, employing the chiral-symmetry-preserving domain wall fermion discretization and physical values of light and strange quark masses. The CS kernel is extracted from the ratios of pion quasi-transverse-momentum-dependent wave functions (quasi-TMDWFs) at next-to-leading logarithmic perturbative accuracy. Also for the first time, we utilize the recently proposed Coulomb-gauge-fixed quasi-TMDWF correlator without a Wilson line. We observe significantly slower signal decay with increasing quark separations compared to the established gauge-invariant method with a staple-shaped Wilson line. This enables us to determine the CS kernel at large nonperturbative transverse separations and find its near-linear dependence on the latter. Our result is consistent with the recent lattice calculation using gauge-invariant quasi-TMDWFs, and agrees with various recent phenomenological parametrizations of experimental data.

   ↳ hep-lathep-exhep-phnucl-ex+1PLB(2024)·40 citations
5. 05*

   Hydra: Computer Vision for Data Quality Monitoring

   Thomas Britton🇺🇸 · Torri Jeske🇺🇸 · David Lawrence🇺🇸 · Kishansingh Rajput🇺🇸

   Hydra is a system which utilizes computer vision to perform near real time data quality management, initially developed for Hall-D in 2019. Since then, it has been deployed across all experimental halls at Jefferson Lab, with the CLAS12 collaboration in Hall-B being the first outside of GlueX to fully utilize Hydra. The system comprises back end processes that manage the models, their inferences, and the data flow. The front-end components, accessible via web pages, allow detector experts and shift crews to view and interact with the system. This talk will give an overview of the Hydra system as well as highlight significant developments in Hydra's feature set, acute challenges with operating Hydra in all halls, and lessons learned along the way.

   ↳ cs.CVnucl-exphysics.ins-detJINST(2024)·0 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.