Deuteron Target Research Articles

Compact Monoenergetic Proton Generator in MeV Region Using NANOGAN

For simple applications, such as the calibration of a charged particle detector, a multi-MeV proton generator may be preferable to cyclotrons or electrostatic accelerators such as Van de Graaff. Thus, a compact proton generating system, consisting of 10Ghz ECR ion source NANOGAN and a deuteron target, was developed at the Research Center for Nuclear Physics at Osaka University. A 3He2+ beam was generated by the NANOGAN with the acceleration voltage of 20∼45 kV in an experiment that utilized the fusion reaction 3He + deuteron (d) → proton(p) + 4He. The monochromatic protons with energies of 14.67 MeV were successfully obtained at the atmosphere side of the target in the experimental setup, when a novel target base with a thin metal foil and Polyimide film window are used.

Effect of T-Invariance Violation in Scattering of Polarized 3He Nuclei on Tensor-Polarized Deuterons

In the interaction of a transversely polarized nuclear beam with a tensor-polarized deuteron target, a nonzero value of the component of the total cross section corresponding to this combination of polarizations is an unambiguous signal ofT-invariance violation whileP-parity is preserved. The method developed earlier for calculating this component of the total cross section forpdscattering based on the Glauber theory has been generalized by us to the case of3Hedscattering, and its energy dependence in the range of beam energies 0.1–1 GeV/nucleon has been calculated. It is found that in3Hedcollisions, in contrast topdscattering, the contribution of only one type ofT-violating nucleon-nucleon forces dominates, which is essential for extraction of the unknown constant of this interaction from the corresponding data.

Secondary neutron production from thick target deuteron breakup

Secondary neutron production from thick target deuteron breakup

Measurement of the Tensor-Analyzing Power Component T20 for Incoherent Negative Pion Photoproduction on a Deuteron

New results for the T20-component of the tensor-analyzing power of the incoherent negative pion photoproduction are presented. The experiment was performed for the electron beam energy of 800 MeV at the VEPP-3 storage ring in 2021. To extract the T20-component, we used asymmetry with respect to the change in the sign of the tensor polarization of the deuteron target. Identification of the reaction events was carried out by the detection of two protons in coincidence. Experimental data were compared with the results of statistical simulation, considering the interaction between the NN and πN subsystems in the final state of the reaction.

Electron and neutrino scattering off the deuteron in a relativistic framework

We build a relativistic model to perform calculations of exclusive, semi-exclusive and inclusive unpolarized cross sections and various polarization observables in electron and neutrino scattering experiments with deuteron targets. The strong interaction dynamics is defined by an explicit dynamical unitary representation of the Poincar\'e group, where representations of space translations and rotations in the interacting and non-interacting representations are the same. The Argonne V18 potential is used to construct a relativistic nucleon-nucleon interaction reproducing the experimental deuteron binding energy and nucleon-nucleon scattering observables. Our formalism does not include the pion production channel and neglects two-body contributions in the electromagnetic as well as in the weak nuclear current operator. We show that it is applicable to processes at kinematics, where the internal two-nucleon energy remains below the pion production threshold but the magnitude of the three-momentum transfer extends at least to several GeV.

Time-reversal-invariance violation in the Nd system and large NC

A minimal set of five low energy constants (LECs) for time-reversal and parity violating $(\overline{)T}\overline{)P})$ nucleon-nucleon $(NN)$ interactions at low energies $(E<{m}_{\ensuremath{\pi}}^{2}/{M}_{N})$ is given. Using a large-${N}_{C}$ (number of colors in quantum chromodynamics) analysis we show that one linear combination of LECs is $\mathcal{O}({N}_{C})$, three LECs are $\mathcal{O}({N}_{C}^{0})$, and one linear combination of LECs is $\mathcal{O}({N}_{C}^{\ensuremath{-}1})$. We also calculate the $\overline{)T}\overline{)P}$ observables of neutron spin rotation through a polarized deuteron target and a spin correlation coefficient in nucleon-deuteron scattering using pionless effective field theory. Using the large-${N}_{C}$ analysis we show that the spin correlation coefficient and the neutron spin rotation are predominantly determined by the same two LECs in the large-${N}_{C}$ basis.

J/ψ Near-Threshold Photoproduction off the Proton and Neutron with CLAS12

Near-threshold J/ψ photoproduction is a key aspect of the physics program at the Thomas Jefferson National Accelerator Facility (JLab) 12 GeV upgrade due to the wealth of information it has to offer. J/ψ photoproduction proceeds through the exchange of gluons in the t-channel and is expected to provide unique insight about the nucleon gravitational form factors and the nucleon mass radius. The JLab based CLAS Collaboration, which uses the CEBAF Large Acceptance Spectrometer (CLAS12), aims to measure the J/ψ near threshold photoproduction cross section using both a proton and a deuteron target, from threshold up to 10.6 GeV. The deuteron target further offers the possibility of comparing the proton and neutron gluonic form factors and mass radii in a first measurement of the cross sections off a proton or neutron within the deuteron target. The analysis towards these measurements is ongoing and well advanced, with machine learning based techniques for particle identification already designed and validated with CLAS12 data.

Spatial densities of momentum and forces in spin-one hadrons

Densities associated with the energy-momentum tensor are calculated for spin-one targets. These calculations are done in a light front formalism, which accounts for relativistic effects due to boosts and allows for arbitrary spatial localization of the target. These densities include the distribution of momentum, angular momentum, and pressures over a two-dimensional plane transverse to the light front. Results are obtained for both longitudinally and transversely polarized targets, and the formalism is tailored to allow the possibility of massless targets. The momentum density and pressure distributions are calculated for a deuteron target in a light cone convolution model, with which the properties of this model (such as helicity dependence of the densities) is illustrated.

Understanding PDF uncertainty in W boson mass measurements* *JG and DL is supported by the National Natural Science Foundation of China(11875189 and 11835005), as well as the Yangyang Development Fund. KX is supported by the U.S. Department of Energy(DE-SC0007914), U.S. National Science Foundation (PHY-2112829), and in part by the PITT PACC

We study the dependence of the transverse mass distribution of charged leptons and the missing energy on parton distributions (PDFs) adapted to W boson mass measurements at the CDF and ATLAS experiments. We compare the shape variations of the distribution induced by different PDFs and find that the spread of predictions from different PDF sets can be significantly larger than the PDF uncertainty predicted by a specific PDF set. We suggest analyzing the experimental data using up-to-date PDFs to gain a better understanding of the PDF uncertainties in W boson mass measurements. We also perform a series of Lagrange multiplier scans to identify the constraints on the transverse mass distribution imposed by individual data sets in the CT18 global analysis. In the case of the CDF measurement, the distribution is mostly sensitive to d-quark PDFs in the intermediate x region, which are largely constrained by DIS and Drell-Yan data on deuteron targets and Tevatron lepton charge asymmetry data.

TMD observables in unpolarised Semi-Inclusive DIS at COMPASS

In 2016 and 2017, the COMPASS Collaboration at CERN collected a large sample of DIS events with a longitudinally polarised 160 GeV/c muon beam scattering off a liquid hydrogen target. Part of the collected data has been analysed to extract preliminary results for the amplitudes of the modulations in the azimuthal angle of the charged hadrons and for their transverse-momentum distributions. These observables give relevant information for the study of the transverse momentum and spin structure of the nucleon. Similarly to the results obtained in COMPASS with a deuteron target, the azimuthal asymmetries exhibit interesting kinematic dependences, while the squared-transverse-momentum distributions can be described by the sum of two exponential functions.

Measurement of the helicity dependence for single $$\pi ^{0}$$ photoproduction from the deuteron

The helicity-dependent single $\pi^{0}$ photoproduction cross section on the deuteron and the angular dependence of the double polarisation observable $E$ for the quasi-free single $\pi^0$ production off the proton and the neutron have been measured for the first time from the threshold region up to the photon energy 1.4 GeV. The experiment was performed at the tagged photon facility of the MAMI accelerator and used a circularly polarised photon beam and longitudinally polarised deuteron target. The reaction products were detected using the large acceptance Crystal Ball/TAPS calorimeter, which covered 97% of the full solid angle. Comparing the cross section from the deuteron with the sum of free nucleon cross sections provides a quantitative estimate of the effects of the nuclear medium on pion production. In contrast, comparison of $E$ helicity asymmetry data from quasi-free protons off deuterium with data from a free proton target indicates that nuclear effects do not significantly affect this observable. As a consequence, it is deduced that the helicity asymmetry $E$ on a free neutron can be reliably extracted from measurements on a deuteron in quasi-free kinematics.

Perturbative correction to the adiabatic approximation for (d, p) reactions

The adiabatic distorted wave approximation (ADWA) is widely used by the nuclear community to analyse deuteron stripping (d, p) experiments. It provides a quick way to take into account an important property of the reaction mechanism: deuteron breakup. In this work we provide a numerical quantification of a perturbative correction to this theory, recently proposed in Johnson (2014 J. Phys. G: Nucl. Part. Phys. 41 094005) for separable rank-one nucleon–proton potentials. The correction involves an additional, nonlocal, term in the effective deuteron–target ADWA potential in the entrance channel. We test the calculations with perturbative corrections against continuum-discretized coupled channel predictions which treat deuteron breakup exactly.

A modern Q-meter system to measure the polarization of solid polarized targets

Solid polarized targets are widely used in nuclear and particle physics experiments. Polarization measurements for these targets are normally performed using nuclear magnetic resonance (NMR). The Liverpool Q-meter was developed in the late 1970s and became the de facto standard for these NMR-based measurements. However, it has become increasingly difficult to obtain the required number of Q-meter channels, as the components have become obsolete. The Los Alamos National Laboratory (LANL) high energy nuclear physics (HENP) group has developed a new NMR-based Q-meter system, building upon the basic Liverpool design. The new Q-meter introduces several improvements, such as remote tuning and compact design, while being less costly to produce. These improvements have the potential to increase the accuracy of the polarization measurements, thereby reducing the experimental systematic uncertainties. This modern Q-meter has been successfully tested with both polarized proton and deuteron targets.

Deuteron uncertainties in the determination of proton PDFs

We evaluate the uncertainties due to nuclear effects in global fits of proton parton distribution functions (PDFs) that utilise deep-inelastic scattering and Drell–Yan data on deuterium targets. To do this we use an iterative procedure to determine proton and deuteron PDFs simultaneously, each including the uncertainties in the other. We apply this procedure to determine the nuclear uncertainties in the SLAC, BCDMS, NMC and DYE866/NuSea fixed target deuteron data included in the NNPDF3.1 global fit. We show that the effect of the nuclear uncertainty on the proton PDFs is small, and that the increase in overall uncertainties is insignificant once we correct for nuclear effects.

Flow in collisions of light nuclei

In this talk we discuss several interesting aspects of collective flow in small systems in reference to planned future experiments. First, we bring in the novel possibility of exploring elliptic flow with heavy nuclei collisions on polarized deuteron targets, accessible in AFTER@LHC program after Long Shutdown 3. Then we discuss the Glauber model predictions for the presently considered 16O −16O program at RHIC and the LHC. Finally, we turn to our previous proposal concerning specific flow signatures of intrinsic correlations (such as the predicted α clusterization) in the structure of light nuclei in collisions with heavy nuclei. In particular, 12C–heavy nucleus ultrarelativistic reactions would provide insight into the ground-state 12C structure, complementary to traditional nuclear structure measures.

Studying neutron structure at Jefferson Lab through electron scattering off the deuteron, using CLAS12 and the Central Neutron Detector

Generalised Parton Distributions (GPDs) offer a way of imaging nucleons through 3D tomography. They can be accessed experimentally in processes such as Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP), where a high energy electron scatters from a quark inside a nucleon and a high energy photon or meson is produced as a result. Jefferson Lab has recently completed its energy upgrade and Hall B houses the new, large-acceptance CLAS12 detector array optimised for measurements of DVCS and DVMP in the newly accessible kinematic regime. Measurements on the proton and neutron are complementary and both are necessary to facilitate access to the full set of GPDs and enable their flavour separation. Neutron DVCS and DVMP are possible with the use of a deuteron target – the first CLAS12 experiment with which has started taking data this year. To enable exclusive reconstruction of DVCS and neutral-meson DVMP, a dedicated detector for recoiling neutrons – the Central Neutron Detector (CND) – was integrated into CLAS12. We present the first CLAS12 deuteron-target experiment, with a focus on the performance of the CND.

Double polarisation observables G and E and helicity dependent cross section for single π 0 photoproduction off proton and neutron at MAMI

Meson photoproduction, like other photon-induced reactions, allow to study the excitation spectra of the nucleons and, in combination with the use of polarised beam and/or target, allow to determine the properties of the nucleon resonances by accessing many different polarisation observables with great accuracy. The A2 Collaboration, located at the MAMI facility in Mainz, used elliptically polarised photons on longitudinally polarised proton and deuteron targets, for energies up to 1.6 GeV. From the experimental data, it was possible to extract the double polarisation observables E and G on single π 0 photoproduction off the proton and the neutron. New precise results on the helicity-dependent total and differential cross sections on the deuteron were collected too.

New COMPASS results on kaon multiplicities from SIDIS

Preliminary COMPASS results on kaon multiplicities produced in semi-inclusive deep inelastic scattering of 160 GeV muons off a pure proton target are presented. The results constitute a data set of more than 600 data points, covering a large x, Q 2 and z domain in a fine binning with W > 5GeV/c2. The results from the sum of the z-integrated multiplicities M(K+)+M(K−) are presented versus x and compared to earlier COMPASS results on a deuteron target and to other experiments.In addition, we show the K−/K+ as well as /p multiplicity ratios measured for hadrons carrying a large fraction z of the virtual-photon energy, 0.5 < z < 1. The data were obtained using a 160 GeV muon beam and an isoscalar 6LiD target. For values of z larger than 0.8, the results contradict expectations obtained using the formalism of (next-to-) leading order perturbative quantum chromodynamics. In particular the data show a strong dependence upon the missing mass Mx , not expected from the calculations. The results suggest that additional corrections to the formalism may be required to take into account the phase space available for hadronization.

Neutron Capture Cross Sections of Radioactive Nuclei

Alternative methods to calculate neutron capture cross sections on radioactive nuclei are reported using the theory of Inclusive Non-Elastic Breakup (INEB) developed by Hussein and McVoy [1]. The statistical coupled-channels theory proposed in Ref. [2] is further extended in the realm of random matrices. The case of reactions with the projectile and the target being two-cluster nuclei is also analyzed and applications are made for scattering from a deuteron target [3]. An extension of the theory to a three-cluster projectile incident on a two-cluster target is also discussed. The theoretical developments described here should open new possibilities to obtain information on the neutron capture cross sections of radioactive nuclei using indirect methods.

Total reaction cross section on a deuteron target and the eclipse effect of the constituent neutron and proton

Background: Eclipse effect of the neutron and proton in a deuteron target is essential to correctly describe high-energy deuteron scattering. The nucleus-deuteron scattering needs information not only on the nucleus-proton but also the nucleus-neutron interaction, for which no direct measurement of the nucleus-neutron cross sections is available for unstable nuclei. Purpose: We systematically evaluated the total reaction cross sections by a deuteron target to explore the feasibility of extracting the nucleus-neutron interaction from measurable cross sections. Methods: High-energy nucleus-deuteron collision is described by the Glauber model, in which the proton and neutron configuration of the deuteron is explicitly taken into account. Results: Our calculation reproduces available experimental total reaction cross section data on the nucleus-deuteron scattering. The possibility of extracting the nucleus-neutron total reaction cross section from nucleus-deuteron and nucleus-proton total reaction cross sections is explored. The total reaction cross sections of a nucleus by proton, neutron, and deuteron targets can be expressed, to good accuracy, in terms of the nuclear matter radius and neutron skin thickness. Incident-energy dependence of the total reaction cross sections is examined. Conclusions: The total reaction cross section on a deuteron target includes information on both the nucleus-neutron and nucleus-proton profile functions. Measuring the cross sections by deuteron and proton targets is a promising tool to extract the nuclear size properties.