Wed·Apr 20, 2022Wednesday·April 20, 2022

1. 01*

   Evolution of the $\gamma$-ray strength function in neodymium isotopes

   M. Guttormsen🇳🇴 · K. O. Ay🇹🇷 · M. Ozgur🇹🇷 · E. Algin · A. C. Larsen🇳🇴 · F. L. Bello Garrote🇳🇴 · H. C. Berg · L. Crespo Campo🇳🇴 · T. Dahl-Jacobsen · F. W. Furmyr · D. Gjestvang · A. Görgen🇳🇴 and 15 other authors

   The experimental gamma-ray strength functions (gamma-SFs) of 142,144-151Nd have been studied for gamma-ray energies up to the neutron separation energy. The results represent a unique set of gamma-SFs for an isotopic chain with increasing nuclear deformation. The data reveal how the low-energy enhancement, the scissors mode and the pygmy dipole resonance evolve with nuclear deformation and mass number. The data indicate that the mechanisms behind the low-energy enhancement and the scissors mode are decoupled from each other.

   nucl-exnucl-thPRC(2022)·27 citations
2. 02*

   Bottomonium-like tetraquarks in a chiral quark model

   Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Jorge Segovia🇪🇸

   The low-lying bottomonium-like tetraquarks $b\bar{b}q\bar{q}$ $(q=u,d,s)$ with spin-parity $J^P=0^{+}$, $1^{+}$ and $2^{+}$, and isospin $I=0,1$ or $\frac{1}{2}$, are systematically investigated within the theoretical framework of real- and complex-scaling range of a chiral quark model, which has already been successfully applied in analysis of several multiquark systems. A complete four-body $S$-wave function, which includes meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color configurations are considered. In the $b\bar{b}q\bar{q}$ $(q=u,d)$ tetraquark system, we found resonance states of $B^{(\ast )}{\bar{B}}^{(\ast )}$, ${\rm Y}\omega$, ${\rm Y}\rho$ and ${\eta }_b\rho$ nature with all possible $I(J^P)$ quantum numbers. Their masses are generally located in the energy range $11.0-11.3$ GeV and their widths are less than $10$ MeV. In addition, extremely narrow resonances, with two-meson strong decay widths less than $1.5$ MeV, are obtained in both $b\bar{b}u\bar{s}$ and $b\bar{b}s\bar{s}$ tetraquark systems. Particularly, four radial excitations of ${\rm Y}{K}^{\ast }$ and ${\eta }_b{K}^{\ast }$ are found at $\sim 11.1$ GeV in $J^P=0^{+}$, $1^{+}$ and $2^{+}$ channels of $b\bar{b}u\bar{s}$ system. One ${\rm Y}(1S)\varphi (2S)$ resonance state is obtained at $11.28$ GeV in the $J^P=1^{+}$ sector.

   ↳ hep-phhep-exhep-latnucl-ex+1PRD(2022)·8 citations
3. 03*

   "Flux+Mutability": A Conditional Generative Approach to One-Class Classification and Anomaly Detection

   C. Fanelli🇺🇸 · J. Giroux🇨🇦 · Z. Papandreou🇨🇦

   Anomaly Detection is becoming increasingly popular within the experimental physics community. At experiments such as the Large Hadron Collider, anomaly detection is at the forefront of finding new physics beyond the Standard Model. This paper details the implementation of a novel Machine Learning architecture, called Flux+Mutability, which combines cutting-edge conditional generative models with clustering algorithms. In the `flux' stage we learn the distribution of a reference class. The `mutability' stage at inference addresses if data significantly deviates from the reference class. We demonstrate the validity of our approach and its connection to multiple problems spanning from one-class classification to anomaly detection. In particular, we apply our method to the isolation of neutral showers in an electromagnetic calorimeter and show its performance in detecting anomalous dijets events from standard QCD background. This approach limits assumptions on the reference sample and remains agnostic to the complementary class of objects of a given problem. We describe the possibility of dynamically generating a reference population and defining selection criteria via quantile cuts. Remarkably this flexible architecture can be deployed for a wide range of problems, and applications like multi-class classification or data quality control are left for further exploration.

   ↳ cs.LGhep-exnucl-exphysics.data-anMach.Learn.Sci.Tech.(2022)·17 citations
4. 04*

   Artificial Intelligence for Imaging Cherenkov Detectors at the EIC

   C. Fanelli🇺🇸 · A. Mahmood🇨🇦

   Imaging Cherenkov detectors form the backbone of particle identification (PID) at the future Electron Ion Collider (EIC). Currently all the designs for the first EIC detector proposal use a dual Ring Imaging CHerenkov (dRICH) detector in the hadron endcap, a Detector for Internally Reflected Cherenkov (DIRC) light in the barrel, and a modular RICH (mRICH) in the electron endcap. These detectors involve optical processes with many photons that need to be tracked through complex surfaces at the simulation level, while for reconstruction they rely on pattern recognition of ring images. This proceeding summarizes ongoing efforts and possible applications of AI for imaging Cherenkov detectors at EIC. In particular we will provide the example of the dRICH for the AI-assisted design and of the DIRC for simulation and particle identification from complex patterns and discuss possible advantages of using AI.

   ↳ physics.ins-detcs.AIhep-exnucl-exJINST(2022)·2 citations
5. 05*

   $J/\psi$ near threshold in holographic QCD: A and D gravitational form factors

   Kiminad A. Mamo🇺🇸 · Ismail Zahed🇺🇸

   The diffractive photoproduction of $J/\Psi$ on a nucleon, is mostly due to gluonic exchanges at all $\sqrt{s}$. In holographic QCD (large number of colors and strong ${}^{\prime }$t Hooft coupling), these exchanges are captured by gravitons near threshold, and their Reggeized Pomeron form asymptotically. We revisit our holographic analysis of the A and D gravitational form factors in light of the new lattice data, and use them to refine our predictions for the photoproduction of $J/\Psi$ near threshold, and the comparison to the GlueX data. We use these results to estimate the scalar and mass radii of the nucleon, and describe the gravitational pressure and shear across a nucleon.

   ↳ hep-phhep-exhep-thnucl-ex+1PRD(2022)·94 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.