Thu·May 16, 2024Thursday·May 16, 2024

1. 01*

   Coherent ${\pi }^0\eta d$ photoproduction at forward deuteron angles measured at BGOOD

   A.J. Clara Figueiredo🇩🇪 · T.C. Jude🇩🇪 · S. Alef🇩🇪 · P.L. Cole🇺🇸 · R. Di Salvo🇮🇹 · D. Elsner🇩🇪 · A. Fantini🇮🇹 · O. Freyermuth🇩🇪 · F. Frommberger🇩🇪 · F. Ghio🇮🇹 · J. Groß🇩🇪 · K. Kohl🇩🇪 and 9 other authors

   The coherent reaction, $\gamma d\to {\pi }^0\eta d$ was studied with the BGOOD experiment at ELSA from threshold to a centre-of-mass energy of 3200\,MeV. A full kinematic reconstruction was made, with final state deuterons identified in the forward spectrometer and ${\pi }^0$ and $\eta$ decays in the central BGO Rugby Ball. The strength of the differential cross section exceeds what can be described by models of coherent photoproduction at forward angles by orders of magnitude. The distribution of the differential cross section has an excellent agreement with a model including quasi-free $\Delta \pi$ photoproduction, pion re-scattering and $N(1535)$ formation and subsequent nucleon coalescence to the deuteron. This also gives a reasonable description of the two-body invariant mass distributions and naturally explains the similar magnitudes of this channel and ${\pi }^0{\pi }^{0}d$ coherent photoproduction.

   nucl-exPLB(2026)·9 citations
2. 02*

   Tentative estimates of $\mathcal{B}(X(3872)\to {\pi }^0{\pi }^0{\chi }_{c1})$ and $\mathcal{B}(X(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1})$

   N. N. Achasov🇷🇺 · G. N. Shestakov🇷🇺

   The rates of the $X(3872)\to {\pi }^0{\pi }^0{\chi }_{c1}$ and $X(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1}$ decays are estimated in the model of the triangle loop diagrams with charmed $D^{\ast }\bar{D}D$ and ${\bar{D}}^{\ast }D\bar{D}$ mesons in the loops. There are the triangle logarithmic singularities in the physical region of the $X(3872)\to {\pi }^0{\pi }^0{\chi }_{c1}$ decay which manifest themselves as narrow peaks in the ${\pi }^0{\chi }_{c1}$ mass spectrum near the $D^0{\bar{D}}^0$ threshold. The model predicts approximately the same branching fractions of the $X(3872)\to {\pi }^0{\pi }^0{\chi }_{c1}$ and $X(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1}$ decays at the level of about (0.8-1.7)$\times 10^{-4}$. A distinct prediction of the model is the value of the ratio $\mathcal{R}=\mathcal{B}(X(3872)\to {\pi }^{+}{\pi }^{-}{\chi }_{c1})/\mathcal{B}(X(3872)\to {\pi }^0{\pi }^0{\chi }_{c1})\approx 1.1$. It weakly depends on the $X(3872)$ resonance parameters and indicates a significant violation of the isotopic symmetry according to which one would expect $\mathcal{R}=2$.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2024)·7 citations
3. 03*

   Systematic investigation of the nuclear multiple deformations in U+U collisions with A Multi-Phase Transport model

   Zaining Wang🇨🇳 · Jinhui Chen🇨🇳 · Hao-jie Xu🇨🇳 · Jie Zhao🇨🇳

   Relativistic heavy ion collisions provide a unique opportunity to study the shape of colliding nuclei, even up to higher-order multiple deformations. In this work, several observables that are sensitive to quadrupole and hexadecapole deformations of Uranium-238 in relativistic U+U collisions have been systematically investigated with A Multi-Phase Transport model. We find that the flow harmonic $v_2$, the $v_2$ and mean transverse momentum correlation, and the three-particle asymmetry cumulant ${\mathrm{ac}}_2\{3\}$ are sensitive to nuclear quadrupole deformation, while ${\mathrm{ac}}_2\{3\}$ and nonlinear response coefficient ${\chi }_{4,22}$ are sensitive to nuclear hexadecapole deformation. Our results from transport model studies are in qualitative agreement with previous hydrodynamic studies. The results indicate that the uncertainties of the hexadecapole deformation of Uranium on the quadrupole deformation determination can be reduced by the abundance of correlation observables provided by the relativistic heavy ion collisions.

   ↳ nucl-thnucl-exPRC(2024)·17 citations
4. 04*

   Forward & Far-Forward Heavy Hadrons with JETHAD: A High-energy Viewpoint

   Francesco Giovanni Celiberto🇪🇸

   Inspired by the recent finding that semi-inclusive detections of heavy hadrons exhibit fair stabilization patterns in high-energy resummed distributions against (missing) higher-order corrections, we review and extend our studies on the hadroproduction of light and heavy hadrons tagged in forward and far-forward rapidity ranges. We analyze the NLL/NLO+ behavior of rapidity rates and angular multiplicities via the JETHAD method, where the resummation of next-to-leading energy logarithms and beyond is consistently embodied in the collinear picture. We explore kinematic regions that are within LHC typical acceptances, as well as novel sectors accessible thanks the combined tagging of a far-forward light or heavy hadron at future Forward Physics Facilities and a of central particle at LHC experiments via a precise timing-coincidence setup.

   ↳ hep-phhep-exnucl-exnucl-thParticles(2024)·18 citations
5. 05*

   Beam test results of the prototype of the multi wire drift chamber for the CSR external-target experiment

   Zhi Qin🇨🇳 · Zhoubo He🇨🇳 · Zhe Cao🇨🇳 · Tao Chen🇨🇳 · Zhi Deng🇨🇳 · Limin Duan🇨🇳 · Dong Guo🇨🇳 · Rongjiang Hu🇨🇳 · Jie Kong🇨🇳 · Canwen Liu🇨🇳 · Peng Ma🇨🇳 · Xianglun Wei🇨🇳 and 7 other authors

   The half-size prototype of the multi wire drift chamber (MWDC) for the cooling storage ring (CSR) external-target experiment (CEE) was assembled and tested in 350 MeV/u Kr+Fe reactions on the heavy ion research facility in Lanzhou (HIRFL). The prototype consists of 6 sense layers, where the sense wires are stretched in three directions X, U and V, meeting $0^{\circ }$, $30^{\circ }$ and $-30^{\circ }$ with respect to the vertical axis, respectively. The sensitive area of the prototype is $76\mathrm{cm}\times 76\mathrm{cm}$. The amplified and shaped signals from the anode wires are digitized in a serial capacity array. Being operated with 1500 V high voltage on the anode wires, the efficiency for each layer is beyond 95\%. The tracking residual is about $301\pm 2\mu \mathrm{m}$. The performance meets the requirements of CEE.

   ↳ physics.ins-dethep-exnucl-exNucl.Sci.Tech.(2025)·3 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.