Tue·Jul 18, 2023Tuesday·July 18, 2023

1. 01*

   Transverse single spin asymmetry for very forward neutron production in polarized $p+p$ collisions at $\sqrt{s}=510$ GeV

   M. H. Kim (for the RHICf Collaboration)🇰🇷

   In the high-energy $p+p$ collisions, the transverse single spin asymmetry for very forward neutron production has been interpreted by an interference between $\pi$ (spin flip) and $a_1$ (spin non-flip) exchange with a non-zero phase shift. The $\pi$ and $a_1$ exchange model predicted the neutron asymmetry would increase in magnitude with transverse momentum ($p_{\text{T}}$) in $p_{\text{T}}<0.4$ GeV/$c$. In June 2017, the RHICf experiment installed an electromagnetic calorimeter at the zero-degree area of the STAR experiment at the Relativistic Heavy Ion Collider and measured the neutron asymmetry in a wide $p_{\text{T}}$ range of $0<p_{\text{T}}<1$ GeV/$c$ from polarized $p+p$ collisions at $\sqrt{s}=510$ GeV. The RHICf data allows us to investigate the kinematic dependence of the neutron asymmetry in detail, which not only can test the $\pi$ and $a_1$ exchange model in the higher $p_{\text{T}}$ range but also can study the $\sqrt{s}$ dependence by comparing with the previous measurements. We present the preliminary result and analysis status of the neutron asymmetry measured by the RHICf experiment. In order to understand the RHICf result, a theoretical calculation other than Reggeon exchange will also be discussed.

   nucl-exhep-ex0 citations
2. 02*

   Studies of nuclear equation of state with the HIRFL-CSR external-target experiment

   Dong Guo🇨🇳 · Xionghong He🇨🇳 · Pengcheng Li🇨🇳 · Zhi Qin🇨🇳 · Chenlu Hu🇨🇳 · Botan Wang🇨🇳 · Yingjie Zhou🇨🇳 · Kun Zheng🇨🇳 · Yapeng Zhang🇨🇳 · Xianglun Wei🇨🇳 · Herun Yang🇨🇳 · Dongdong Hu🇨🇳 and 7 other authors

   The HIRFL-CSR external-target experiment (CEE) under construction is expected to provide novel opportunities to the studies of the thermodynamic properties, namely the equation of state of nuclear matter (nEOS) with heavy ion collisions at a few hundreds MeV/u beam energies. Based on Geant 4 packages, the fast simulations of the detector responses to the collision events generated using transport model are conducted. The overall performance of CEE, including spatial resolution of hits, momentum resolution of tracks and particle identification ability has been investigated. Various observables proposed to probe the nEOS, such as the production of light clusters, $\mathrm{t}{/}^3\mathrm{He}$ yield ratio, the radial flow, ${\pi }^{-}/{\pi }^{+}$ yield ratio and the neutral kaon yields, have been reconstructed. The feasibility of studying nEOS beyond the saturation density via the aforementioned observables to be measured with CEE has been demonstrated.

   nucl-ex3 citations
3. 03*

   Measurement of CollinearDrop jet mass and its correlation with SoftDrop groomed jet substructure observables in $\sqrt{s}=200$ GeV $pp$ collisions by STAR

   Youqi Song (for the STAR Collaboration)🇺🇸

   Jet substructure variables aim to reveal details of the parton fragmentation and hadronization processes that create a jet. By removing collinear radiation while maintaining the soft radiation components, one can construct CollinearDrop jet observables, which have enhanced sensitivity to the soft phase space within jets. We present a CollinearDrop jet measurement, corrected for detector effects with a machine learning method, MultiFold, and its correlation with groomed jet observables, in $pp$ collisions at $\sqrt{s}=200$ GeV at STAR. We demonstrate that the population of jets with a large non-perturbative contribution can be significantly enhanced by selecting on higher CollinearDrop jet mass fractions. In addition, we observe an anti-correlation between the amount of grooming and the angular scale of the first hard splitting of the jet.

   nucl-ex34 citations
4. 04*

   Beam Spin Asymmetry Measurements of Deeply Virtual ${\pi }^0$ Production with CLAS12

   A. Kim (1) · S. Diehl (2 and 1)🇩🇪 · K. Joo (1)🇺🇸 · V.Kubarovsky (3) · P.Achenbach (3) · Z.Akbar (4 and 5) · J. S. Alvarado (6)🇫🇷 · Whitney R. Armstrong (7)🇺🇸 · H.Atac (8) · H.Avakian (3) · C. Ayerbe Gayoso (9)🇺🇸 · L. Barion (10)🇮🇹 and 145 other authors

   The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive ${\pi }^0$ production in a wide kinematic region with the photon virtualities $Q^2$ up to 8 GeV${}^2$ and the Bjorken scaling variable $x_B$ in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions.The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD ${\bar{E}}_T$, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the proton's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities.

   nucl-exPLB(2024)·14 citations
5. 05*

   Understanding the total width of the $3_1^{-}$ state in ${}^{12}\mathrm{C}$

   K. C. W. Li🇿🇦 · R. Neveling🇿🇦 · P. Adsley🇿🇦 · H. Fujita🇯🇵 · P. Papka🇿🇦 · F. D. Smit🇿🇦 · J. W. Brümmer🇿🇦 · L. M. Donaldson🇿🇦 · M. N. Harakeh🇳🇱 · Tz. Kokalova🇬🇧 · E. Nikolskii🇷🇺 · W. Paulsen🇳🇴 and 3 other authors

   Recent measurements indicate that the previously established upper limit for the $\gamma$-decay branch of the $3_1^{-}$ resonance in ${}^{12}\text{C}$ at $E_x=9.641(5)$ MeV may be incorrect. As a result, the $3_1^{-}$ resonance has been suggested as a significant resonance for mediating the triple-$\alpha$ reaction at high temperatures above 2 GK. Accurate estimations of the $3_1^{-}$ contribution to the triple-$\alpha$ reaction rate require accurate knowledge of not only the radiative width, but also the total width. In anticipation of future measurements to more accurately determine the $\gamma$-decay branch of the $3_1^{-}$ resonance, the objective of this work is to accurately determine the total width of the $3_1^{-}$ resonance. An evaluation was performed on all previous results considered in the current ENSDF average of 46(3) keV for the physical total width (FWHM) of the $3_1^{-}$ resonance in ${}^{12}\text{C}$. Significant unaccounted-for uncertainties and a misstated result were discovered in these previous results, leading to an invalid ENSDF average. In this work, the new global \textbf{R}-matrix analysis performed on direct-reaction data yields a formal total width of $\Gamma (E_r)=46(2)$ keV and an observed total width of ${\Gamma }_{\text{obs}}(E_r)=38(2)$ keV for the $3_1^{-}$ resonance. An observed total width of ${\Gamma }_{\text{obs}}(E_r)=38(2)$ keV is recommended for the $3_1^{-}$ resonance in ${}^{12}\mathrm{C}$. This observed total width should be employed for future evaluations of the observed total radiative width for the $3_1^{-}$ resonance and its contribution to the high-temperature triple-$\alpha$ reaction rate.

   nucl-exnucl-thPRC(2024)·3 citations
6. 06*

   A large 'Active Magnetic Shield' for a high-precision experiment

   C. Abel🇬🇧 · N.J. Ayres🇨🇭 · G. Ban🇫🇷 · G. Bison🇨🇭 · K. Bodek🇵🇱 · V. Bondar🇨🇭 · T. Bouillaud🇫🇷 · E.Chanel🇨🇭 · J. Chen🇫🇷 · W. Chen🇨🇭 · P.-J. Chiu🇨🇭 · C.B. Crawford🇺🇸 and 39 other authors

   We present a novel Active Magnetic Shield (AMS), designed and implemented for the n2EDM experiment at the Paul Scherrer Institute. The experiment will perform a high-sensitivity search for the electric dipole moment of the neutron. Magnetic-field stability and control is of key importance for n2EDM. A large, cubic, 5m side length, magnetically shielded room (MSR) provides a passive, quasi-static shielding-factor of about 10^5 for its inner sensitive volume. The AMS consists of a system of eight complex, feedback-controlled compensation coils constructed on an irregular grid spanned on a volume of less than 1000m^3 around the MSR. The AMS is designed to provide a stable and uniform magnetic-field environment around the MSR, while being reasonably compact. The system can compensate static and variable magnetic fields up to +-50muT (homogeneous components) and +-5muT (first-order gradients), suppressing them to a few muT in the sub-Hertz frequency range. The presented design concept and implementation of the AMS fulfills the requirements of the n2EDM experiment and can be useful for other applications, where magnetically silent environments are important and spatial constraints inhibit simpler geometrical solutions.

   ↳ physics.ins-dethep-exnucl-exEPJC(2023)·10 citations
7. 07*

   Implementing an electronic sideband offset lock for precision spectroscopy in radium

   Tenzin Rabga · Kevin G. Bailey🇺🇸 · Michael Bishof🇺🇸 · Donald W. Booth · Matthew R. Dietrich · John P. Greene · Peter Mueller · Thomas P. O'Connor🇺🇸 · Jaideep T. Singh🇺🇸

   We demonstrate laser frequency stabilization with at least 6 GHz of offset tunability using an in-phase/quadrature (IQ) modulator to generate electronic sidebands (ESB) on a titanium sapphire laser at 714 nm and we apply this technique to the precision spectroscopy of ${}^{226}$Ra, and ${}^{225}$Ra. By locking the laser to a single resonance of a high finesse optical cavity and adjusting the lock offset, we determine the frequency difference between the magneto-optical trap (MOT) transitions in the two isotopes to be $2630.0\pm 0.3$ MHz, a factor of 29 more precise than the previously available data. Using the known value of the hyperfine splitting of the ${}^3{P}_1$ level, we calculate the isotope shift for the ${}^1{S}_0$ to ${}^3{P}_1$ transition to be $2267.0\pm 2.2$ MHz, which is a factor of 8 more precise than the best available value. Our technique could be applied to countless other atomic systems to provide unprecedented precision in isotope shift spectroscopy and other relative frequency comparisons.

   ↳ physics.atom-phnucl-exphysics.opticsOpt.Express(2023)·3 citations
8. 08*

   Transverse Single Spin Asymmetries of charged hadrons at forward and backward rapidity from $p^{\uparrow }+p$, $p^{\uparrow }+\mathrm{Al}$, and $p^{\uparrow }+\mathrm{Au}$ collisions in PHENIX

   Jeongsu Bok🇺🇸

   Transverse Single Spin Asymmetries (TSSAs) in transversely polarized proton-proton collisions ($p^{\uparrow }+p$) have been a fruitful source for studying the spin structure of the proton. In the 2015 RHIC data taking periods, collisions of polarized protons with nuclei ($p^{\uparrow }+A$) were made for the first time. The measurements of TSSAs in $p^{\uparrow }+p$ and $p^{\uparrow }+A$ collisions can provide a unique opportunity to investigate the origin of TSSA in a gluon-rich target nucleus and provide a tool to study nuclear effects in $p+A$ collisions. This presentation will report PHENIX results of TSSAs for charged hadrons ($h^{\pm }$) at forward and backward rapidity ($1.4<|\eta |<2.4$) over the transverse momentum ranges $1.25<p_T<7.0\mathrm{GeV}/c$ and Feynman-$x$ ranges ($-0.2<x_F<0.2$) from $p^{\uparrow }+p$, $p^{\uparrow }+\mathrm{Al}$, and $p^{\uparrow }+\mathrm{Au}$ collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV.

   ↳ hep-exnucl-ex0 citations
9. 09*

   Prospects of transverse $\Lambda$ and $\bar{\Lambda }$ polarization measurements at LHCb

   Cynthia Nunez (on behalf of the LHCb collaboration)🇺🇸

   Transverse $\Lambda$ polarization observed over four decades ago contradicted expectations from early leading-order perturbative QCD calculations. Measurements of $\Lambda$ polarization from unpolarized $pp$ and $p$A collisions have been previously observed to increase as a function of $x_F$ and $p_T$ up to a few GeV range and approximately independent of beam energy. Recent studies have linked polarization to the process of hadronization, which describes how particular hadrons are formed from scattered quarks and gluons. The high energy of the LHC and the coverage and precision measurement possibilities from LHCb forward geometry are ideal for studying hyperon polarization as a function of both $p_T$ and $x_F$. This contribution presents the status and prospects of hyperon polarization measurements in $pp$, $p$Pb, Pb$p$, and fixed-target $p$A collisions at LHCb.

   ↳ hep-exnucl-ex0 citations
10. 10*

    Effects of multi-scale jet-medium interactions on jet substructures

    JETSCAPE Collaboration: Y. Tachibana · A. Angerami · R. Arora · S. A. Bass · S. Cao · Y. Chen · T. Dai · L. Du · R. Ehlers · H. Elfner · W. Fan · R. J. Fries and 47 other authors

    We utilize event-by-event Monte Carlo simulations within the JETSCAPE framework to examine scale-dependent jet-medium interactions in heavy-ion collisions. The reduction in jet-medium interaction during the early high-virtuality stage, where the medium is resolved at a short distance scale, is emphasized as a key element in explaining multiple jet observables, particularly substructures, simultaneously. By employing the MATTER+LBT setup, which incorporates this explicit reduction of medium effects at high virtuality, we investigate jet substructure observables, such as Soft Drop groomed observables. When contrasted with existing data, our findings spotlight the significant influence of the reduction at the early high-virtuality stages. Furthermore, we study the substructure of gamma-tagged jets, providing predictive insights for future experimental analyses. This broadens our understanding of the various contributing factors involved in modifying jet substructures.

    ↳ hep-phhep-exnucl-exnucl-thPoS(2024)·0 citations
11. 11*

    Artificial Intelligence for the Electron Ion Collider (AI4EIC)

    C. Allaire · R. Ammendola · E.-C. Aschenauer · M. Balandat · M. Battaglieri · J. Bernauer · M. Bondì · N. Branson · T. Britton · A. Butter · I. Chahrour · P. Chatagnon and 84 other authors

    The Electron-Ion Collider (EIC), a state-of-the-art facility for studying the strong force, is expected to begin commissioning its first experiments in 2028. This is an opportune time for artificial intelligence (AI) to be included from the start at this facility and in all phases that lead up to the experiments. The second annual workshop organized by the AI4EIC working group, which recently took place, centered on exploring all current and prospective application areas of AI for the EIC. This workshop is not only beneficial for the EIC, but also provides valuable insights for the newly established ePIC collaboration at EIC. This paper summarizes the different activities and R&D projects covered across the sessions of the workshop and provides an overview of the goals, approaches and strategies regarding AI/ML in the EIC community, as well as cutting-edge techniques currently studied in other experiments.

    ↳ physics.acc-phcs.LGhep-exnucl-ex+1Comput.Softw.Big Sci.(2024)·31 citations
12. 12*

    On the problems of creating a nuclear-optical frequency standard based on 229Th

    F. F. Karpeshin · L. F. Vitushkin🇷🇺

    The most probable candidate for the role of a nuclear optical standard is the 8.338-eV isomer of the 229mTh isotope of the thorium nucleus. Ways of using the resonance properties of the electron shell as an optical resonator to create laser-nuclear technologies necessary for the optical pumping of nuclear isomers and other manipulations of atomic nuclei leading to the creation of a next-generation frequency standard and nuclear-optical clocks based on them are discussed. Deep relations between the physics of resonance electron-nuclear interactions and the true solution of the thorium puzzle are shown. The article discusses important principles of resonant optical pumping, such as the presence of a finite width in the intermediate electronic state, and others that are usually overlooked with a fatal result for the experiment. The wide application of the various physics of these processes will predetermine a revolutionary leap in the development of new laser-nuclear technologies.

    ↳ nucl-thnucl-ex3 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.