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Ye, Zhihong

Publications and source records attributed to Ye, Zhihong.

12 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Pion and kaon structure at the electron-ion collider

Understanding the origin and dynamics of hadron structure and in turn that of atomic nuclei is a central goal of nuclear physics. Here, this challenge entails the questions of how does the roughly 1 GeV mass-scale that characterizes atomic nuclei appear; why does it have the observed value; and, enigmatically, why are the composite Nambu-Goldstone (NG) bosons in quantum chromodynamics (QCD) abnormally light in comparison? In this perspective, we provide an analysis of the mass budget of the pion and proton in QCD; discuss the special role of the kaon, which lies near the boundary between dominance of strong and Higgs mass-generation mechanisms; and explain the need for a coherent effort in QCD phenomenology and continuum calculations, in exa-scale computing as provided by lattice QCD, and in experiments to make progress in understanding the origins of hadron masses and the distribution of that mass within them. We compare the unique capabilities foreseen at the electron-ion collider (EIC) with those at the hadron-electron ring accelerator (HERA), the only previous electron-proton collider; and describe five key experimental measurements, enabled by the EIC and aimed at delivering fundamental insights that will generate concrete answers to the questions of how mass and structure arise in the pion and kaon, the Standard Model's NG modes, whose surprisingly low mass is critical to the evolution of our Universe.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2019

Measurements of Nonsinglet Moments of the Nucleon Structure Functions and Comparison to Predictions from Lattice QCD for Q 2 = 4 GeV 2

We present extractions of the nucleon non-singlet moments utilizing new precision data on the deuteron F 2 structure function at large Bjorken-x determined via the Rosenbluth separation technique at Jefferson Lab Experimental Hall C. These new data are combined with a complementary set of data on the proton previously measured in Hall C at similar kinematics and world data sets on the proton and deuteron at lower x measured at SLAC and CERN. The new Jefferson Lab data provide coverage of the upper third of the x range, crucial for precision determination of the higher moments. In contrast to previous extractions, these moments have been corrected for nuclear effects in the deuteron using a new global fit to the deuteron and proton data. The obtained experimental moments represent an order of magnitude improvement in precision over previous extractions using high x data. Furthermore, recent exciting developments in Lattice QCD calculations provide a first ever comparison of these new experimental results with calculations of moments carried out at the physical pion mass, as well as an innovative approach which first calculates the quark distributions directly before determining moments.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Open Charm Production and Nuclear Gluon Densities

Open Charm Production and Nuclear Gluon Densities Very little is known about nuclear gluon densities. We explore the direct measurements of nuclear gluon densities via open charm and beauty production at an Electron-Ion Collider (EIC). In the high-x ranges x ~ 0.05-0.15 (antishadowing) and x>0.3 (EMC effect) strong modifications are expected relative to the incoherent sum of nucleon gluon distributions. These effects offer insight into non-nucleonic degrees of freedom and the QCD structure of nucleon-nucleon interactions. We describe the charm production rates in nuclear deep-inelastic scattering (DIS) at large x_B, and comment on methods for charm reconstruction using next-generation detectors at the EIC (pi/K identification, tracking, vertex detection). Presenter : Prof. HYDE, Charles (Old Dominion University)

Hyde, Charles↗
DOE OSTI2015

SoLID-SIDIS: Future Measurements of Transversity, TMDs and more

Over the past few decades, investigations of the nucleon structure mainly focused on the one-dimensional study of parton distributions and structure functions. New theoretical developments, including both transverse momentum distributions (TMDs) and generalized parton distributions (GPDs), provide a new way to understand the 3-dimensional structure of the nucleon. TMDs give access to the nucleon tomography in the momentum space, and also provide an opportunity to evaluate the contribution of quarks’ and gluons’ orbital angular momenta to the nucleon spin. The experimental study of TMDs requires a device with high luminosity, large kinematic coverage and great detection resolutions. With the Jefferson Lab (JLab) 12 GeV electron beam, we have proposed a Solenoidal Large Intensity Device (SoLID) in Hall A which is capable of performing such measurements. Several newly approved experiments will perform measurements of both the single and double spin asymmetries via semi-inclusive deep inelastic scattering (SIDIS) from polarized 3 He ("neutron") and proton targets. The new data will provide important information to extract TMDs with unprecedented precision. Besides, we are also able to use SoLID to explore many more important physics topics. Several experiments for the measurements of PVDIS and J=y production have been approved, and new proposals are under development. For example, with the similar SIDIS configuration, we are actively developing new measurements to study GPDs via deep virtual Compton scattering (DVCS) with polarized targets, doubly-DVCS, deep virtual meson production, time-like Compton scattering, and so on. Our collaboration has submitted the pre-conceptual design report to JLab and successfully passed the Director’s Review in early 2015. Our collaborators are focusing on optimizing the detector system, finalizing the detector designs and proceeding on the detector R&D. We are looking forward to having the DOE Science Review in the near future.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Proton remains puzzling

Nucleons are building blocks of visible matter, and are responsible for more than 99% of the visible mass in the universe despite the fact that the discovery of the Higgs boson is almost irrelevant to the origin of the proton mass. While major progress has been made in the last two decades in understanding the proton spin puzzle discovered in the late 1980s by the European Muon Collaboration, a new proton puzzle emerged in the last several years concerning the proton charge radius, which is the charge weighted size of the proton. In this paper we will review the latest situation concerning the proton charge radius, mass and spin, and discuss upcoming new experiments addressing these puzzles, as well as implications for new physics.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Proton Remains Puzzling

Nucleons are building blocks of visible matter, and are responsible for more than 99% of the visible mass in the universe despite the fact that the discovery of the Higgs boson is almost irrelevant to the origin of the proton mass. While major progress has been made in the last two decades in understanding the proton spin puzzle discovered in the late 1980s by the European Muon Collaboration, a new proton puzzle emerged in the last several years concerning the proton charge radius, which is the charge weighted size of the proton. In this paper we will review the latest situation concerning the proton charge radius, mass and spin, and discuss upcoming new experiments addressing these puzzles, as well as implications for new physics.

Gao, Haiyan↗
DOE OSTI2014

Precision Measurement of the Neutron Twist-3 Matrix Element dn2: Probing Color Forces

Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25 lte x lte 0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized 3He target. In this dedicated experiment, the spin structure function g2 on 3He was determined with precision at large x, and the neutron twist-three matrix element dn2 was measured at ?Q2? of 3.21 and 4.32 GeV2/c2, with an absolute precision of about 10?5. Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ?Q2?= 5 GeV2/c2. Combining dn2 and a newly extracted twist-four matrix element, fn2, the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 60 MeV/fm in magnitude.

Posik, Matthew↗
DOE OSTI2013

Short Range Correlations in Nuclei at Large xbj through Inclusive Quasi-Elastic Electron Scattering

The experiment, E08-014, in Hall-A at Jefferson Lab aims to study the short-range correlations (SRC) which are necessary to explain the nuclear strength absent in the mean field theory. The cross sections for 2H, 3He, 4He, 12C, 40Ca and 48Ca, were measured via inclusive quasi-elastic electron scattering from these nuclei in a Q2 range between 0.8 and 2.8 (GeV/c) 2 for x>1. The cross section ratios of heavy nuclei to 2H were extracted to study two-nucleon SRC for 1

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Three-Nucleon Short Range Correlations studies in Inclusive Scattering for $ x_ {bj}> 2$

Short range correlations (SRC) can be studied in inclusive quasi-elastic electron scattering as the ratio of the cross sections of heavy to light nuclei provides a measure two-nucleon SRC (2N-SRC) and three-nucleon SRC (3N-SRC) in the region of 12 with better accuracy, and to examine the isospin dependence of SRCs in inclusive scattering using the calcium isotopes. E08014 ran in Hall~A in 2011 and we will briefly present the experimental setup along with status of the data analysis followed by a discussion of the preliminary results.

Ye, Zhihong↗
DOE OSTI2012

Study of Three-Nucleon Short Range Correlations in Inclusive Electron Scattering

Inclusive electron scattering is a powerful tool to study short range correlations (SRCs) in nuclei. Two nucleon SRCs (2N-SRCs) were first observed in data from SLAC and further studied at Jefferson Lab, appearing, between $1.4 < x< 2$, as plateaus in the per nucleon cross section ratio of heavy to light nuclei. The Jefferson Lab experiments also provided the first evidence of three nucleon SRCs (3N-SRCs) at $x>2$. However, because of limited statistics of the earlier experiments, the scaling behavior of 3N-SRCs is not well established. Jefferson Lab experiment E08014 ran in April and May of 2011 in Hall~A and aimed to study the onset of 3N-SRCs with better accuracy and, for the first time, to examine the isospin dependence of SRCs. The experiment will be briefly described followed by a discussion of the data analysis and the presentation of the preliminary results.

Ye, Zhihong↗
DOE OSTI2012

Study of Three-Nucleon Short Range Correlations in x>2 regime

Inclusive electron scattering is a powerful tool to study nuclear short range correlations (SRCs). Recent experiments in Jefferson Lab have established their presence of substantial 2N correlations by taking the ratio of the cross sections of heavy to light nuclei in the region of $1 < x < 2$. However the experimental situation is much more uncertain with regard to three nucleon SRCs (3N-SRCs) which may dominate for $x > 2$. Jefferson Lab experiment E08014 experiment ran in April and May of 2011 in Hall-A and was designed to study the onset of 3N-SRCs with better accuracy and, for the first time, to examine the isospin dependence of SRCs in inclusive scattering. The experiment will be briefly described followed by a discussion of the data analysis and the presentation of any preliminary data.

Ye, Zhihong↗