Bulletin of the American Physical Society
6th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Sunday–Friday, November 26–December 1 2023; Hawaii, the Big Island
Session F06: Hadronic Physics - QCD I |
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Chair: Kei Suzuki, Japan Atomic Energy Agency Room: Hilton Waikoloa Village Queens 5 |
Thursday, November 30, 2023 9:00AM - 9:15AM |
F06.00001: Extraction of the strong coupling from HERA and EIC (simulated) inclusive deep inelastic scattering data Abhay L Deshpande, Zuhal Seyma Demiroglu, Barak A Schmookler, Katarzyna Wichmann, Paul Newman, Barak Schmookler, Salim Cerci, Deniz Cerci The sensitivity to the strong coupling $alpha_S(M^2_Z)$ is investigated using existing Deep Inelastic Scattering data from HERA in combination with projected future measurements from the Electron Ion Collider (EIC) in a next-to-next-to-leading order QCD analysis. A potentially world-leading level of precision is achievable when combining simulated inclusive neutral current EIC data with inclusive charged and neutral current measurements from HERA, with or without the addition of HERA inclusive jet and dijet data. The result can be obtained with significantly less than one year of projected EIC data at the lower end of the EIC centre-of-mass energy range. Some questions remain over the magnitude of uncertainties due to missing higher orders in the theoretical framework. |
Thursday, November 30, 2023 9:15AM - 9:30AM |
F06.00002: Cold QCD physics program with sPHENIX Sookhyun Lee sPHENIX is a new detector fully instrumented with tracking and calorimetry (hadronic and electromagnetic) in the midrapidity region at the Relativistic Heavy Ion Collider (RHIC) at BNL. The detector is dedicated to measure a comprehensive set of jet, open heavy flavor and upsilon observables. Upon completion of construction in April 2023, sPHENIX has been commissioning and taking first data in the RHIC 2023 Heavy Ion Run. With the pp and pA Runs planned for the following years, sPHENIX provides great opportunities for studying the partonic structure and dynamics in nucleons and nuclei. The unique capability to collide polarized protons on protons/nuclei enables measurements sensitive to the polarized structure of the proton and nuclear effects with spin observables. In addition, excellent capabilities of jets and heavy flavor measurements open up new ways to study hadron formation in the complementary kinematic regions to LHC. This talk will present the prospects and readiness of the sPHENIX cold QCD program. |
Thursday, November 30, 2023 9:30AM - 9:45AM |
F06.00003: Heavy Quark Polarization and nonperturbative QCD in spin-directed momentum transfer Gary R Goldstein, Simonetta Liuti, Dennis Sivers Spin dependent gluon distributions in the nucleon can lead to distinctive features in the angular dependences and asymmetries of pp and electroproduction processes. Of particular interest are heavy quark production processes, wherein single spin asymmetries of the heavy quarks adumbrate the underlying gluon spin dependences and nonperturbative mechanisms. Produced target hyperon spi asymmetries connect to the gluon. |
Thursday, November 30, 2023 9:45AM - 10:00AM |
F06.00004: Status of the J-PARC E16 experiment for the measurement of mass spectrum of vector mesons at finite density Satomi Nakasuga The J-PARC E16 experiment aims at measuring the spectral change of vector mesons in nuclei to study the finite density effect on the hadron mass. We will obtain mass spectra via di-electron decays of vector mesons produced in 30 GeV proton-nucleus reactions. Electrons are clean probes that are free from final state interaction, whereas the branching ratio of dilepton decays of vector mesons is small at the order of 10-4. To accumulate high statistics, we have developed a spectrometer with large acceptance and a high-rate capability to utilize a high intensity proton beam of 1010 proton/spill (2-sec duration) at J-PARC. Enormous backgrounds of pions are eliminated by two-stage electron identification detectors, a hadron blind detector (HBD) together with a lead-glass calorimeter (LG). The invariant mass is reconstructed with a resolution of 6 MeV/c2, realized with the tracking devices of a GEM tracker (GTR) and a silicon strip detector (SSD). |
Thursday, November 30, 2023 10:00AM - 10:15AM |
F06.00005: anomaly detection and data quality monitoring for spinQuest target and detector systems Jordan D Roberts SpinQuest will measure the sea quarks Sivers asymmetry, with a target transversely polarized with respect to the incoming 120 GeV proton beam. The Sivers asymmetry describes the distribution of the unpolarized quarks inside a polarized nucleon. SpinQuest will explore the properties of the nucleon's spin composition by investigating the correlation of the light antiquarks motion relative to the nucleon spin. An online monitoring system has been developed to scan the polarized target system data stream and polarization data while integrating information from detectors and event reconstruction for near-continuous quality checking of the incoming data. Online monitoring of the target system and detector package will play a vital role in ensuring optimal performance to obtain the highest figure of merit possible given the experimental circumstances. This novel monitoring system enhances the debugging process during commissioning and data acquisition through the use of machine learning pattern recognition techniques and anomaly detection. This scheme promises to aid target operators and shift takers during the two-year-long production runs to begin in Fall of 2023 at Fermilab. |
Thursday, November 30, 2023 10:15AM - 10:30AM |
F06.00006: Transverse single spin asymmetry measurement of very forward neutron production in the RHICf experiment Yuji Goto The RHICf collaboration has installed an electromagnetic calorimeter in the very forward zero-degree region of the STAR experiment at the Relativistic Heavy Ion Collider (RHIC) to measure the transverse single spin asymmetry (TSSA) of neutrons over a wide transverse momentum (pT) range with 0 < pT < 1 GeV/c in high-energy polarized p+p collisions with collision energy √s = 510 GeV. The finite TSSA of the very forward neutron production in high-energy polarized p+p collisions was first measured at √s = 200 GeV in the IP12 experiment at RHIC, and combined measurements at several collision energies in the subsequent PHENIX experiment showed a tendency to increase with pT in the range pT < 0.4 GeV/c. The RHICf experiment allows us to extend the measurement range to the higher pT region and to investigate whether there is a √s dependence of the neutron TSSA. In this talk we will present the experimental results and discuss theoretical attempts to understand the results. |
Thursday, November 30, 2023 10:30AM - 10:45AM |
F06.00007: Measurement of p+d/p+p Cross-Section Ratio of Drell-Yan Process at FNAL-SeaQuest Kenichi Nakano The partonic structure of the proton is of great interest in hadron physics. Particularly the distribution of anti-quarks has gained a lot of attention due to its unique sensitivity to the dynamics of the strong force (i.e. QCD). A large flavor asymmetry of the unpolarized distributions of light anti-quarks (i.e. anti-d(x) / anti-u(x)) was observed by several experiments through the deep-inelastic muon scattering and the Drell-Yan process. The mechanism of the asymmetry has been studied via various theoretical models. SeaQuest at Fermilab is a fixed-target experiment to measure the Drell-Yan process in proton+proton and proton+deuteron scattering, using the 120-GeV proton beam and targets of LH2, LD2, C, Fe and W. SeaQuest's primary goal is to precisely measure the anti-quark flavor asymmetry, anti-d(x)/anti-u(x), at large x through the ratio of p+d and p+p cross sections. The latest results from SeaQuest using an updated and higher precision measurement on anti-d(x)/anti-u(x) will be presented in the context of various theoretical models. |
Thursday, November 30, 2023 10:45AM - 11:00AM |
F06.00008: Measurement of $Lambda_c^+/D^0$ as a function of event multiplicity in pp and p–Pb collisions at $sqrt{s_{NN}}=5.02$ TeV with the ALICE experiment Oveis Sheibani Measurements of charm baryon and meson production in pp and p–Pb minimum bias collisions and as a function of multiplicity, help to investigate hadronization processes and their modification across the collision systems from pp to Pb–Pb, and from low to high multiplicities. Recent measurements of the fragmentation fractions of charm hadrons in pp and p–Pb challenge the universality of fragmentation in the presence of a hadronic medium. In addition, the ratio of $p_{T}$ spectra of $Lambda_c^+/D^0$ in pp collisions, shows a separation between the highest and the lowest multiplicity classes within $5.3sigma$, with the maximum discrepancy occurring for $2 GeV/c$. Models that adopt a dynamical approach to hadronization, such as PYTHIA and the statistical hadronization model, can act as a bridge to study the connection between data and the theoretical framework. |
Thursday, November 30, 2023 11:00AM - 11:15AM |
F06.00009: Measurement 1-Jetttiness event shape at High Q2 using the H1 detector Sookhyun Lee First measurements of the 1-jettiness event shape observables are performed in neutral-current deep-inelastic scattering at HERA. The data amounting to an integrated luminosity of 351.6 pb-1 were recorded with the H1 detector in the years 2003-2007 at √s = 319 GeV and the measurements are restricted to high momentum transfer Q2 > 150 GeV2. The 1-jettiness observable τ1b is defined such that it is Lorentz invariant and equivalent to the thrust observable defined in the Breit frame. Triple-differential cross sections are presented as a function of τ1b, Q2, and the inelasticity y. The cross sections are sensitive to parton distribution functions of the proton, the strong coupling constant, parton shower, and hadronisation effects. The presence of events where one of the two hemispheres in the Breit frame is empty was confirmed for the first time, a phenomenon that was only predicted by perturbative QCD calculations and never previously measured. The data are compared to selected Monte Carlo predictions and higher-order pQCD calculations. This talk will discuss the implications of the results on a wide range of QCD phenomena that the measurements probe. |
Thursday, November 30, 2023 11:15AM - 11:30AM |
F06.00010: Effects of Renormalon and Resummation Schemes on Extractions of the Strong Coupling alpha_s(m_Z) Christopher Lee, Jim Talbert, Guido Bell, Bin Yan, Yiannis Makris We examine effective field theory extractions of the strong coupling constant alpha_s(m_Z) from e^+e^− event shapes, with an emphasis on the role of non-perturbative renormalon cancellation schemes and perturbative scale variations in describing the physics of thrust, the canonical event shape variable. We calculate e^+e^− thrust to N^3LL resummed and three-loop fixed-order accuracy in matched Soft Collinear Effective Theory (SCET). We consider the effect of different schemes to cancel renormalon ambiguities between perturbative and the dominant nonperturbative effects on event shapes, and choices of perturbative profiles scales in the resummed perturbative predictions. We then perform a global fit of the resulting distributions to available data spanning center-of-mass energies between 35-207 GeV. Relevant subsets of our results are consistent with prior SCET extractions of alpha_s(m_Z) available in the literature. However, we also reach a number of additional conclusions. Critically, we observe that the combined effect of altering the renormalon cancellation scheme and/or profile parameters can lead to noticeably different extracted values of alpha_s and the dominant nonperturbative shift parameter Omega_1. This may have to be considered as an additional systematic theory uncertainty in these extractions, possibly reducing the current tension that exists between these extracts and the PDG world average. We suggest that fits performed over windows dominated by dijet (rather than tri- or multi-jet) events are typically of a higher quality than those that extend into the far-tails of distributions, providing a roadmap for further theoretical and experimental improvements. |
Thursday, November 30, 2023 11:30AM - 11:45AM |
F06.00011: Measurements of long-range correlations and $v_{2}(eta)$ in small system with ALICE Yuko Sekiguchi Measurements of long-range angular correlations are one of the important tools to evaluate the interplay between the initial- and final-state effects in small collision systems in view of understanding the evidence of collectivity. The charged-particle multiplicity distribution as a function of pseudorapidity ($eta$) is asymmetric in p--Pb collisions. Since the mean free path depends on multiplicity, the $v_{n}(eta)$ reflects the dynamics of collectivity in p--Pb collisions. The measurement of $v_{n}(eta)$ in p--Pb collisions is an important study of how charged-particle multiplicity and anisotropic flow relate to the longitudinal evolution of the system. In this talk, we present results of super long-range two-particle azimuthal correlations and $v_{2}(eta)$ in p--Pb collisions at $sqrt{s_{NN}}$ = 5.02 TeV and also pp collisions at $sqrt{s}$ = 13 TeV measured with ALICE. These measurements utilize the Forward Multiplicity Detector, which allows for unprecedented pseudorapidity ranges to be explored (up to $Deltaeta~$ 8) and allow to measure the $eta$ dependence of $v_{2}$ over a wide pseudorapidity range (−3.1 $< eta<$ 4.8). Results are compared with the AMPT and hydrodynamical calculations. |
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