Probing Nucleons and Nuclei in High Energy Collisions
Christine A. Aidala, Elke Aschenauer, Fatma Aslan, Alessandro Bacchetta, Ian Balitsky, Sanjin Benic, Shohini Bhattacharya, Mariaelena Boglione, Matthias Burkard… 展开作者
Christine A. Aidala, Elke Aschenauer, Fatma Aslan, Alessandro Bacchetta, Ian Balitsky, Sanjin Benic, Shohini Bhattacharya, Mariaelena Boglione, Matthias Burkardt, Justin Cammarota, Giovanni A. Chirilli, Christopher Cocuzza, Aurore Courtoy, Daniel de Florian, Pasquale Di Nezza, Adrian Dumitru, Sara Fucini, Kenji Fukushima, Yulia Furletova, Leonard Gamberg, Oscar Garcia-Montero, François Gelis, Vadim Guzey, Yoshitaka Hatta, Francesco Hautmann, Timothy J. Hobbs, Tanja Horn, Edmond Iancu, Sylvester Joosten, Zhong-Bo Kang, Raj Kishore, Yuri V. Kovchegov, Peter Kroll, Krešimir Kumerički, Krzysztof Kutak, Tuomas Lappi, Huey-Wen Lin, Xiaohui Liu, Simonetta Liuti, Cédric Lorcé, Heikki Mäntysaari, Cyrille Marquet, Yiannis Makris, Kiminad A. Mamo, Yacine Mehtar-Tani, Andreas Metz, Zein-Eddine Meziani, Gerald A. Miller, Joshua Miller, Asmita Mukherjee, Pavel M. Nadolsky, Fredrick I. Olness, Barbara Pasquini, Bernard Pire, Cristian Pisano, Daniel Pitonyak, Maxim V. Polyakov, Alexei Prokudin, Jian-Wei Qiu, Marco Radici, Abha Rajan, Sangem Rajesh, Matteo Rinaldi, Kaushik Roy, Christophe Royon, Nobuo Sato, Marc Schlegel, Gunar Schnell, Peter Schweitzer, Sergio Scopetta, Ralf Seidl, Kirill Semenov-Tian-Shansky, Andrea Signori, Daria Sokhan, Anna M. Stasto, Lech Szymanowski, Andrey Tarasov, Dionysios Triantafyllopoulos, Thomas Ullrich, Raju Venugopalan, Ivan Vitev, Werner Vogelsang, Anselm Vossen, Bo-Ting Wang, Samuel Wallon, Kazuhiro Watanabe, Christian Weiss, Bo-Wen Xiao, Ho-Ung Yee, Yong Zhao
备注：
Electron Ion Collider, INT 18-3 Program. Published by World Scientific. Duplicates content of arXiv:1912.10965, arXiv:1912.10724, arXiv:1910.03006, arXiv:1910.07982, arXiv:1912.13397, arXiv:1910.01979, arXiv:2001.07862, arXiv:2001.03700, arXiv:1910.01030, arXiv:1910.01273, arXiv:1912.13020, arXiv:1910.06003, arXiv:2001.03655, arXiv:1909.12591, arXiv:1909.09809, arXiv:1910.04806, arXiv:2001.05978
This volume is a collection of contributions for the 7-week program "Probing Nucleons and Nuclei in High Energy Collisions" that was held at the Institute for Nuclear Theory in Seattle, WA, USA, from October 1 until November 16, 2018. The program was dedicated to the physics of the Electron Ion Collider (EIC), the world's first polarized electron-nucleon (ep) and electron-nucleus (eA) collider to be constructed in the USA. These proceedings are organized by chapters, corresponding to the weeks of the program: Week I, Generalized parton distributions; Week II, Transverse spin and TMDs; Week III, Longitudinal spin; Week IV, Symposium week; Weeks V & VI, eA collisions; Week VII, pA and AA collisions. We hope these proceedings will be useful to readers as a compilation of EIC-related science at the end of the second decade of the XXI century.
The importance of the effects of nucleon-nucleon (NN) short-range correlations (SRC) and Gribov inelastic shadowing (IS) on various high energy scattering processes involving nuclear targets is demonstrated within an improved Glauber-Gribov approach.
An overview of recent results with CLAS is presented with emphasis on nucleon resonance studies, nucleon spin structure, and generalized parton distributions.
Status, open questions, and future prospects of the physics of excited nucleons are discussed. Emphasis is on the study of the structure of nucleons via measurements of their electromagnetic transition form factors, the search for "missing" resonances, the spin structure of the nucleon in the resonance region, and connections between the resonance and the deep-inelastic regimes.
Heavy quarkonium production will provide for novel opportunities to study the gluonic structure of the nucleon in the near future. Near threshold quarkonium production allows for direct experimental access of the dynamic origin of the nucleon mass as well as the nature of the color Van der Waals force, while quarkonium production at high energies can be used to create a full three-dimensional tomographic image of the gluons inside the nucleon, constraining the gluonic radius of the nucleon.
We propose a means to detect the nucleon strange quark-antiquark asymmetry, which is predicted as a non-perturbative effect, but still unchecked directly by available experiments. The difference for the $D(c\bar{q})$ and $\bar{D}(\bar{c}q)$ meson production cross sections in neutrino and antineutrino induced charged current deep inelastic scattering is illustrated to be sensitive to the nucleon strange asymmetry. Prospect is given and the effect due to the light quark fragmentation is also discussed for the extraction of the strange asymmetry in future experiments.
We calculate the total and differential quasielastic cross sections for neutrino and antineutrino scattering on nucleons using up to date fits to the nucleon elastic electromagnetic form factors $G_E^p$, $G_E^n$, $G_M^p$, $G_M^n$, and $F_A$ and pseudoscalar form factors. We compare predictions of the cross sections for nucelons and nuclei to experimental data.
Including O(m_c) terms in the coefficient functions and/or O(m_D) twist 3 contributions in the heavy meson distribution amplitudes leads to a non-zero transverse amplitude for exclusive neutrino production of a D pseudoscalar charmed meson on an unpolarized target. We work in the framework of the collinear QCD approach where chiral-odd transversity generalized parton distributions (GPDs) factorize from perturbatively calculable coefficient functions.
The electric dipole moments of the nucleon and light ions are discussed and strategies for disentangling the underlying sources of CP violation beyond the Kobayashi-Maskawa quark-mixing mechanism of the Standard Model are indicated. Contribution to "45 years of nuclear theory at Stony Brook: a tribute to Gerald E. Brown".
We describe a new way to access the chiral odd transversity parton distribution in the proton through the photoproduction of lepton pairs. The basic ingredient is the interference of the usual Bethe Heitler or Drell-Yan amplitudes with the amplitude of a process, where the photon couples to quarks through its chiral-odd distribution amplitude, which is normalized to the magnetic susceptibility of the QCD vacuum. A promising phenomenology of single and double spin observables emerges from the unusual features of this amplitude.
We explore the possibility of probing the nucleon's transversity distribution $δq(x)$ through the final state interaction between two mesons ($π^+π^-$, $πK$, or $K\bar K$) produced in transversely polarized nucleon-nucleon collisions. We present a single spin asymmetry and estimate its magnitude under some assumptions for the transversity distribution function and the unknown interference fragmentation function.
We summarise recent progress in theory and experiment towards understanding etaprime meson interactions with nucleons and nuclei. Highlights include the production mechanism of etaprime mesons in proton-proton collisions close to threshold, the etaprime effective mass shift in nuclei and the determination of the etaprime-nucleon scattering length in free space.
Present and prospective fundamental symmetry tests with nucleons, nuclei and atoms are probing for possible new physics at the TeV scale and beyond. These ongoing and proposed table-top as well as accelerator-based experiments are thus a vital component of the Intensity Frontier. At the same time, these tests provide increasingly sophisticated probes of long-distance strong interactions that are responsible for the structure of nucleons and nuclei. In this community report, some of the most compelling opportunities with nucleons, nuclei and atoms are summarized, drawing largely on input receiv…
We study the possibility to constrain the hidden strangeness content of the nucleon by means of the polarization observables in phi meson electroproduction. We consider the OZI evading direct knockout mechanism that arises from the non-vanishing s\bar{s} sea quark admixture of the nucleon as well as the background of the dominant diffractive and the one-boson-exchange processes. Large sensitivity on the nucleon strangeness are found in several beam-target and beam-recoil double polarization observables. The small \sqrt{s} and W region, which is accesible at some of the current high-energy elec…
We argue that generalized parton distributions (GPDs), accessible in hard exclusive processes, carry information about the spatial distribution of forces experienced by quarks and gluons inside hadrons. This way the measurements of hard exclusive processes open a possibility for direct "measurements" of strong forces in different parts of nucleons and nuclei. Also such studies open a venue for addressing questions of the properties of the quark (gluon) matter inside hadrons and nuclei. We give a simple example of relations between GPDs and properties of "nuclear matter" in finite nuclei.
Dimuon production has been studied in a series of fixed-target experiments at Fermilab during the last two decades. Highlights from these experiments, together with recent results from the Fermilab E866 experiment, are presented. Future prospects for studying the parton distributions in the nucleons and nuclei using dimuon production are also discussed.
We investigate neutrino-nucleus collisions at intermediate energies incorporating quasielastic scattering and Delta(1232) excitation as elementary processes, together with Fermi motion, Pauli blocking and mean-field potentials in the nuclear medium. A full coupled-channel treatment of final state interactions is achieved with a semiclassical BUU transport model. Results for inclusive reactions and nucleon knockout are presented.
We review the production of high-mass lepton pairs in fixed-target experiments, including both Drell-Yan (DY) and heavy quarkonium (J/Psi and Upsilons) production.
We investigate $ϕ$ meson electroproduction to probe the hidden strangeness content of the nucleon. We found that even a small amount of the $s\bar{s}$ admixture in the nucleon wavefunction can lead to a significant change in several double polarization asymmetries in $ϕ$ electroproduction, which can be tested experimentally at current electron facilities.
I review recent progress in the extraction of unpolarized parton distributions in the proton and in nuclei from a unified point of view that highlights how the interplay between high energy particle physics and lower energy nuclear physics can be of mutual benefit to either field. Areas of overlap range from the search for physics beyond the standard model at the LHC, to the study of the non perturbative structure of nucleons and the emergence of nuclei from quark and gluon degrees of freedom, to the interaction of colored probes in a cold nuclear medium.
Deepening our knowledge of the partonic content of nucleons and nuclei represents a central endeavour of modern high-energy and nuclear physics, with ramifications in related disciplines such as astroparticle physics. There are two main scientific drivers motivating these investigations of the partonic structure of hadrons. On the one hand, addressing fundamental open issues in our understanding in the strong interactions such as the origin of the nucleon mass, spin, and transverse structure; the presence of heavy quarks in the nucleon wave function; and the possible onset of novel gluon-domin…
We consider the spin-isospin-independent central part of the residual nucleon-nucleon potential in finite spherical nuclei taking into account the deformation effects of the nucleons within the surrounding nuclear environment. It is shown that inside the nucleus the short-range repulsive contribution of the potential is increased and the intermediate attraction is decreased. We identify the growth of the radial component of the spin-isospin independent short-range part of the in-medium nucleon-nucleon interaction as the responsible agent that prevents the radial collapse of the nucleus.
In this high-$x$ region, both the flavour content and structure of the nucleon parton distribution functions remains relatively poorly known. New LHCb measurements of Z and charm jet associated production could indicate a valence-like intrinsic-charm component in the proton wave function, and measurements of Z production in pPb collisions provide new constraints on the partonic structure of nucleons bound inside nuclei. Here we will discuss these new LHCb measurements and comparisons with state-of-the-art parton distribution function calculations.
The description of electromagnetic interactions with hadrons from the quark level requires knowledge of the underlying quark-gluon ingredients. I discuss some properties of the quark-photon vertex and quark Compton vertex, along with the role of electromagnetic gauge invariance and vector-meson dominance. A simple parametrization for the quark-photon vertex is given.
The central role of soft nucleon matrix elements in reactions of high energy electrons or real photons with nucleons is emphasized. These soft matrix elements are described in terms of skewed parton distributions. Their connections to ordinary parton distributions, form factors, Compton scattering and hard meson electroproduction is discussed.
On the basis of the Brueckner-Hartree-Fock method with the nucleon-nucleon forces obtained from lattice QCD simulations, the properties of the medium-heavy doubly-magic nuclei such as 16^O and 40^Ca are investigated. We found that those nuclei are bound for the pseudo-scalar meson mass M_PS ~ 470 MeV. The mass number dependence of the binding energies, single-particle spectra and density distributions are qualitatively consistent with those expected from empirical data at the physical point, although these hypothetical nuclei at heavy quark mass have smaller binding energies than the real nucl…
The cross sections for a variety of diffractive processes in proton-nucleus scattering, associated with large gaps in rapidity, are calculated within an improved Glauber-Gribov theory, where the inelastic shadowing corrections are summed to all orders by employing the dipole representation. The effects of nucleon correlations, leading to a modification of the nuclear thickness function, are also taken into account. Numerical calculations are performed for the energies of the HERA-B experiment, and the RHIC and LHC colliders, and for several nuclei. It is found that whereas the Gribov correctio…
With the kinetic freeze-out nucleons and antinucleons obtained from the quark combination model, we study the production of light nuclei and antinuclei in the (anti-)nucleon coalescence mechanism in relativistic heavy ion collisions. We derive analytic formulas of the momentum distributions of different light nuclei and apply them to compute transverse momentum ($p_T$) spectra of (anti-)deuterons ($d$, $\bar d$) and (anti-)tritons ($t$, $\bar t$) in Au-Au collisions at $\sqrt{s_{NN}}=$7.7, 11.5, 19.6, 27, 39, 54.4 GeV. We find that the experimental data available for these $p_T$ spectra can be…
The properties of strange and charm mesons in nuclear matter and nuclei are reviewed. Different frameworks are presented and discussed paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the in-medium properties of these mesons are also addressed, in particular in connection with the future FAIR facility at GSI.
Recent experimental data on inclusive and exclusive lepton and hadron scattering off nuclei have renewed the interest in theoretical and experimental studies of Short Range Correlations (SRC), due to the relevant impact they may have not only on the structure of ordinary nuclei but on the structure of hadronic matter at high densities as well. One of the ultimate aim of these studies is the determination of the probability of two- and three-nucleon correlations in nuclei. To this end, we have studied the possibility to extract these probabilities from a novel analysis of inclusive A(e, e')X pr…
We derive the cross-section for exclusive vector meson production in high energy deeply inelastic scattering off a deuteron target that disintegrates into a proton and a neutron carrying large relative momentum in the final state. This cross-section can be expressed in terms of a novel gluon Transition Generalized Parton Distribution (T-GPD); the hard scale in the final state makes the T-GPD sensitive to the short distance nucleon-nucleon interaction. We perform a toy model computation of this process in a perturbative framework and discuss the time scales that allow the separation of initial …
The parton content of the nucleon is explored within a meson-cloud model developed to derive light-cone wave functions for the physical nucleon. The model is here applied to study electromagnetic form factors, distribution amplitudes and nucleon-to-meson transition distribution amplitudes.
I outline an ambitious program which aims to achieve a unified description of nucleon and nuclear properties based on one chiral effective field theory.
The physics of electromagnetic excitation of nucleon resonances and of their relevance in nucleon structure studies are discussed. Preliminary data from the CLAS detector on the N-Delta(1232) transition multipoles, the helicity amplitudes of the N*(1535), and the search for so-called "missing resonances" at Jefferson Lab are presented.
Open problems in the study of the nucleon structure using electromagnetic probes are discussed. The focus is on experimental aspects in the regime of strong interaction QCD. Significant progress in our understanding of the nucleon structure in this domain of QCD may be expected in the first decade of the next millenium. This is due to major experimental and theoretical efforts currently underway in this field.
We study lepton flavour-violating interactions which could result in the $τ$-lepton production in the $ν_μN$ scattering or in $μ\to τ$ conversion on nucleons at high energies. Phenomenological bounds on the strength of $\barτν_μ\bar{q}q^{'}$ interactions are extracted from the combined result of the NOMAD and CHORUS experiments on searching for $ν_μ - ν_τ$ oscillations. Some of these bounds supersede limits from rare decays. We also propose a ``missing energy'' type experiment searching for $μ- τ$ conversion on nucleons. The experiment can be performed at a present accelerator or at a future n…
The strongly repulsive core of the short-range nucleon-nucleon interaction leads to the existence of high-momentum nucleons in nuclei. Inclusive electron scattering can be used to probe these high-momentum nucleons and study the nature of the corresponding short-range correlations in nuclei. With recent data from Jefferson Lab we have begun to map out the strength of two-nucleon correlations in nuclei, while upcoming experiments should allow us to isolate the presence of multi-nucleon correlations. In addition to their importance in describing nuclear structure, these configurations of correla…
Double meson production of the eta and pion at the threshold region is investigated in order to determine chiral property of the nucleon. The eta can be used as a probe for the negative parity nucleon $N^* \equiv N^*(1535)$ produced in the intermediate state. The coupling of the low energy pion in the final state is then used to extract the sign of the Yukawa coupling, $\gpRR$, which distinguishes the two realizations of chiral symmetry, either naive or mirror, for the nucleon.
Because of its forward coverage, LHCb can probe the valence quark distributions of protons and nuclei at small and large Bjorken-x with high precision. This proceeding presents new LHCb measurements of Z boson production in association with charm jet in the forward region of proton-proton collisions and Z boson production in proton-lead collisions. Z+charm jet production could be sensitive to a valence-like intrinsic-charm component in the proton wave function. The measurements of Z production in proton-lead collisions provide new constraints on the partonic structure of nucleons inside nuclei…
A partial screening of nucleon electric dipole moments (EDMs) in nuclear systems, which is related to the Schiff mechanism known for neutral atomic systems, is discussed. It is shown that the direct contribution from the neutron EDM to the deuteron EDM is partially screened by about 1% in a zero-range approximation calculation.
The quark-meson coupling model, based on a mean field description of non-overlapping nucleon bags bound by the self-consistent exchange of $σ$, $ω$ and $ρ$ mesons, is extended to investigate the properties of finite nuclei. Using the Born-Oppenheimer approximation to describe the interacting quark-meson system, we derive the effective equation of motion for the nucleon, as well as the self-consistent equations for the meson mean fields. The model is first applied to nuclear matter, after which we show some initial results for finite nuclei.
One of the important questions in high energy physics is the relation of quark and gluon spin to that of the nucleons which they comprise. Polarization experiments provide a mechanism to probe the spin properties of elementary particles and provide crucial tests of Quantum Chromodynamics (QCD). The theoretical and experimental status of this fundamental question will be reviewed in this paper.
A chapter to be included in "The DA$\mitΦ$NE Physics Handbook" by the DA$Φ$NE Theory Working Group, this paper covers the phenomenology of low--energy $K N$ physics, with particular emphasis on the problems still to be solved by a careful experimental investigation and on the theoretical tools to analyse it.
I describe how nuclear structure can be predicted from lattice QCD through low-energy effective field theories, using as an example a world simulation with relatively heavy up and down quarks.
While the total orbital angular momentum (OAM) of a definite quark flavor in a longitudinally-polarized nucleon can be obtained through a sum rule involving twist-two generalized parton distribution (GPDs), its distribution as a function of parton momentum in light-front coordinates is more complicated to define and measure because it involves intrinsically twist-three effects. In this paper, we consider two different parton OAM distributions. The first is manifestly gauge invariant, and its moments are local operators and calculable in lattice QCD. We show that it can potentially be measured …
A dynamical quark model of hadron and nucleus structure is proposed. In the frame of the model, called the Strongly Correlated Quark Model, quarks and nucleons inside nuclei are arranged in a crystal--like structure.
The Bloom-Gilman local duality of the inelastic structure function of the proton, the deuteron and light complex nuclei is investigated using available experimental data in the squared four-momentum transfer range from 0.3 to 5 (GeV/c)**2. The results of our analysis suggest that the onset of the Bloom-Gilman local duality is anticipated in complex nuclei with respect to the case of the protonand the deuteron. A possible interpretation of this result in terms of a rescaling effect is discussed with particular emphasis to the possibility of reproducing the damping of the nucleon-resonance trans…
We review recent progress in the understanding of the spin structure of the nucleon. For the free nucleon the issues addressed include the status of the Bjorken and Ellis-Jaffe sum-rules and the role of the axial anomaly. We outline recent work connecting the quark models familiar from hadron spectroscopy to the spin and flavour dependence of the parton distributions. Finally we review the current understanding of nuclear spin structure functions and particularly the extraction of the neutron spin structure function from deuteron data.
The interaction of Nucleon-Nucleon (NN) has certain physical characteristics, which indicated by nucleon, and meson degrees of freedom. The main purpose of this work is calculating the ground state energies of 21 Deutron and Alfa through the two-body system with the exchange of mesons (Pi, segma, omega) that mediated between two nucleons. This paper investigates NN interaction based on the quasi-relativistic decoupled Dirac equation and self-consistent Hartree-Fock formulation. We construct one-boson exchange potential (OBEP) model, where each nucleon is treated as a Dirac particle and acts as…
In this paper we evaluate the double deeply virtual Compton scattering on nucleons and nuclei in the framework of the color dipole model. Both the effects of quark and the gluon shadowing are taken into account.
The recent proposals concerning the usage of the real polarized gamma beam, obtained by the Compton backscattering of the laser photons off the electron beams from either the linear or circular accelerators were considered. The heavy quark photoproduction process giving a unique opportunity to measure polarized gluon distribution was investigated.
We study the mass of a nucleon in a nucleus using a model recently introduced for a nucleon current with a pion cloud component. The method of QCD sum rules is used to determine the mass shifts for nucleons to first order in nuclear density in oxygen-16 and calcium-40, with the pion propagator determined by an optical potential for pion-nucleus scattering. Mass shifts due to the pionic contributions range from negligible in oxygen to -100 MeV in calcium at central nuclear density, with larger shifts in the nuclear surface. The consistency of this model with chiral perturbation theory is demons…
We evaluate the differential cross section for the electroproduction of lepton pairs off a polarized nucleon target in the generalized Bjorken region to leading power accuracy in hard momentum. We discuss the importance of this process for phenomenology of generalized parton distributions. A special attention is given to the sensitivity of physical observables, i.e., diverse asymmetries, to their dependence on scaling variables that allows to map directly the functional two-dimensional surface of generalized parton distributions.
We present an exploratory study using generalized parton distributions of several observables related to transverse degrees of freedom in hadronic structure -- the nucleon transverse momentum, the transverse radius, or impact parameter, and the momentum transfer, $t$, dependence of the longitudinal variable $x$ -- in both nucleons and nuclei.
It is shown that the latest results from NMC and E665 on the $F_2^A(x)/F_2^{D}(x)$ obtained in the shadowing region, bring new evidence of the universal $A$ -- dependence of distorsions of a free nucleon structure function by nuclear medium. The universality holds in the entire $x$ -range and can be explained as a saturation of the distortions of the parton distributions in a four-nucleon system.
The relations between the value of T- and P-violating correlations in neutron scattering and different models of CP violation are discussed. It is shown that a specific structure of CP-odd interactions gives the possibility to obtain the essential information about CP-odd interaction at the quark-gluon level from nuclear experimental data. The up-to-date estimations for CP- violating nucleon coupling constants show that CP violation in neutron scattering is sensitive to many models of CP violation.
We discuss connection between spin-dependent SFs of nucleons and nuclei in the deep inelastic lepton scattering. The case of the deuteron is studied in detail in the Bethe-Salpeter formalism.
We analyze the processes of deep inelastic and quasielastic scattering in the region of x > 1. These processes are found to be very sensitive to the information contained in the nucleon spectral function in nuclei, particularly to the correlations between energy and momentum. Calculations are done using two spectral functions for nuclear matter and one for finite nuclei, ^{16}O. Several approximations are also analyzed and are shown to be inaccurate in this region. These results stress the fact that the region of x > 1 contains important information on nuclear dynamical correlations.
