Deuteron Spectra Research Articles

Analysis of transverse momentum spectra of protons, deuterons, and tritons in symmetric heavy-ion collisions at √(s_NN ) = 200 GeV at the RHIC

Abstract The blast wave model with Tsallis statistics is used to analyze the transverse momentum spectra of the protons (p), deuteron (d), and triton (t) in √(s_NN ) = 200 GeV gold-gold (Au-Au) collisions at RHIC in various centrality bins. In particular transverse momentum ranges, model results closely match experimental data from the PHENIX (p) and STAR (d and t) Collaborations. The data is compared with protons obtained in Cu+Cu collisions and deuteron and triton in Ru+Ru collisions at 200 GeV, center of mass energy from STAR collaboration. Particle spectra are used to derive the kinetic freeze-out temperatures, transverse flow velocities, and freeze-out volumes. According to the findings, the kinetic freeze-out temperature rises as one goes from the central to peripheral collisions. In this transition, the transverse flow velocity and the freeze-out volume both drop. In the collisions of both Collaborations, this work reveals mass-dependent kinetic freeze-out temperature and differential volume possibilities. On the whole, the non-extensivity parameter q decreases with increasing centrality of the studied heavy-ion collisions, and heavier mass particles have smaller values of q, which implies higher degrees of thermalization and equilibrium in more central collisions and for heavier particles.

Centrality dependency of proton, deuteron, and triton’s temperatures in Au+Au collisions at 200 GeV

The transverse momentum (pT) spectra of protons (p), deuterons (d), and tritons (t) in 200 GeV gold–gold (Au + Au) collisions at RHIC are examined across a range of centrality bins using the Levy Tsallis (TS) statistical model. The model's predictions closely match the experimental results from PHENIX (p) and STAR (d and t) Collaborations. Kinetic freeze-out temperatures of hadrons are obtained from particle spectra. The results showed that the kinetic freeze-out temperature decreases as collisions move from center to the periphery. This work found mass-dependent kinetic freeze-out temperatures, heavier particles arrive to the freeze-out phase before lighter ones. Comparison with same data fitted by blast wave function with Tsallis statistics (BWTS) showed that T0 values are increasing from central to peripheral collisions, while in case of TS function (current analysis) it decreases. This behavior puts a question mark on the reliability of using such functions for temperature extraction.

A realistic coalescence model for deuteron production

A microscopic understanding of (anti)deuteron production in hadron–hadron collisions is the subject of many experimental and theoretical efforts in nuclear physics. This topic is also very relevant for astrophysics, since the rare production of antinuclei in our Universe could be a doorway to discover new physics. In this work, we describe a new coalescence afterburner for event generators based on the Wigner function formalism and we apply it to the (anti)deuteron case, taking into account a realistic particle emitting source. The model performance is validated using the EPOS and PYTHIA event generators applied to proton–proton collisions at the centre-of-mass energy sqrt{s}= 13 TeV, triggered for high multiplicity events, and the experimental data measured by ALICE in the same collision system. The model relies on the direct measurement of the particle emitting source carried out by means of nucleon–nucleon femtoscopic correlations in the same collision system and energy. The resulting model is used to predict deuteron differential spectra assuming different deuteron wavefunctions within the Wigner function formalism. The predicted deuteron spectra show a clear sensitivity to the choice of the deuteron wavefunction. The Argonne v_{18} wavefunction provides the best description of the experimental data. This model can now be used to study the production of (anti)deuterons over a wide range of collision energies and be extended to heavier nuclei.

Emissions of Hydrogen Isotopes from the Nuclear Muon Capture Reaction in natSi

The energy spectra of protons, deuterons and tritons produced by the nuclear muon capture reaction in natSi were measured at the M1 beam line of Muon Science Innovative Channel (MuSIC) in Research Center for Nuclear Physics (RCNP) using a counter telescope consisting of a Si detector and a CsI(Tl) scintillation detector. The measured energy spectra were consistent with the previous ones. The experimental energy spectra were compared with theoretical model calculations using the Particle and Heavy Ion Transport code System (PHITS). In PHITS, both the dynamical and statistical processes in the nuclear muon capture reaction are described by the Quantum Molecular Dynamics (QMD) or the modified QMD and the Generalized Evaporation Model (GEM), respectively. The PHITS simulation reproduced generally well the measured proton spectrum at emission energies below 20 MeV, while underestimation was seen at emission energies above 20 MeV. The PHITS simulation underestimates remarkably the measured energy spectra of light complex particles (deuterons, tritons, and alpha particles) in the high energy region.

Production of loosely bound hadron molecules from bottomonium decays

We present multiple results on the production of loosely bound molecules in bottomonium annihilations and ${e}^{+}{e}^{\ensuremath{-}}$ collisions at $\sqrt{s}=10.58\text{ }\text{ }\mathrm{GeV}$. We perform the first comprehensive test of several models for deuteron production against all the existing data in this energy region. We fit the free parameters of the models to reproduce the observed cross sections, and we predict the deuteron spectrum and production and the cross section for the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}d\overline{d}+X$ process both at the $\mathrm{\ensuremath{\Upsilon}}(1,2,3S)$ resonances and at $\sqrt{s}=10.58\text{ }\text{ }\mathrm{GeV}$. The predicted spectra show differences but are all compatible with the uncertainties of the existing data. These differences could be addressed if larger datasets are collected by the Belle II experiment. Fixing the source size parameter to reproduce the deuteron data, we then predict the production rates for $H$ dibaryon and hypertriton in this energy region using a simple coalescence model. Our prediction on the $H$ dibaryon production rate is below the limits set by the direct search at the Belle experiment, but in the range accessible to the Belle II experiment. The systematic effect due to the MC modeling of quarks and gluon fragmentation into baryons is reduced, deriving a new tuning of the pythia 8 Monte Carlo generator using the available measurement of single- and double-particle spectra in $\mathrm{\ensuremath{\Upsilon}}$ decays.

Production characteristics of light (anti-)nuclei from (anti-)nucleon coalescence in heavy ion collisions at energies employed at the RHIC beam energy scan

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 well reproduced. We further study the yields and yield ratios of different light (anti-)nuclei and naturally explain their interesting behaviors as a function of the collision energy. We especially point out that the multi-particle yield ratio $tp/d^2$ should be carefully corrected from hyperon weak decays for protons to probe the production characteristics of light nuclei. All of our results show that the coalescence mechanism for (anti-)nucleons plays a dominant role for the production of light nuclei and antinuclei at the RHIC beam energy scan energies.

Inclusive α production for the Li6+V51 system

Measurement of angular distributions and energy spectra of $\alpha$ and deuterons through breakup, transfer and incomplete fusion processes to dis-entangle their relative contributions and to investigate relative importance of breakup-fusion compared to transfer. Inclusive $\alpha$ production cross-sections have been measured for $^6$Li + $^{51}$V system near Coulomb barrier energies. Theoretical calculations for estimation of various reaction channels contributing to $\alpha$ production have been performed with finite range coupled reaction method using \textsc{FRESCO} code. The cross-sections from non-capture breakup (NCBU) ($\alpha$ + \textit{d}) and 1\textit{n}, 1\textit{p}, and 1\textit{d} transfer channels, compound nuclear decay channel and incomplete fusion (ICF) leading to $\alpha$ production were estimated to get the cumulative production cross-sections. Contributions from breakup, transfer and incomplete fusion channels could reproduce the integral direct $\alpha$ production cross-sections and their angular distributions quite well. The direct $\alpha$ production cross-sections are in agreement with other targets. The $\alpha$ production cross-sections are higher compared to the deuteron production. Kinematic analysis of the energy spectra of $\alpha$ particles and deuterons suggest that $\alpha$ particle spectra is dominated by breakp-fusion and deuteron spectra have contribution of breakup and transfer reactions. A systematic study of direct $\alpha$ production with various targets follow a universal behavior on average but noticeable differences are observed for different targets. A ratio of $\alpha$ and deuteron yields for a wide mass range of targets shows a saturation above barrier and an increasing production of $\alpha$ particles relative to deuteron around Coulomb barrier.

Collision centrality and system size dependences of light nuclei production via dynamical coalescence mechanism

Light (anti-)nuclei in relativistic heavy-ion collisions are considered to be formed by the coalescence mechanism of (anti-)nucleons in the present work. Using a dynamical phase-space coalescence model coupled with a multi-phase transport (AMPT) model, we explore the formation of light clusters such as deuteron, triton and their anti-particles in different centralities for $^{197}$Au + $^{197}$Au collisions at $\sqrt{s_{NN}} = 39$ GeV. The calculated transverse momentum spectra of protons, deuterons, and tritons are comparable to those of experimental data from the RHIC-STAR collaboration. Both coalescence parameters $B_{2}$ for (anti-)deuteron and $B_{3}$ for triton increase with the transverse momentum as well as the collision centrality, and they are comparable with the measured values in experiments. The effect of system size on the production of light nuclei is also investigated by $^{10}$B + $^{10}$B, $^{16}$O + $^{16}$O, $^{40}$Ca + $^{40}$Ca, and $^{197}$Au + $^{197}$Au systems in central collisions. The results show that yields of light nuclei increase with system size, while the values of coalescence parameters present an opposite trend. It is interesting to see that the system size, as well as the centrality dependence of $B_A$ ($A$ = 2, 3), falls into the same group, which further demonstrates production probability of light nuclei is proportional to the size of the fireball. Furthermore, we compare our coalescence results with other models, such as the thermal model and analytic coalescence model, it seems that the description of light nuclei production is consistent with each other.

Understanding the energy dependence of B_2 in heavy ion collisions: interplay of volume and space-momentum correlations

The deuteron coalescence parameter B_2 in proton+proton and nucleus+nucleus collisions in the energy range of sqrt{s_{NN}}= 900–7000 GeV for proton + proton and sqrt{s_{NN}}= 2–2760 GeV for nucleus + nucleus collisions is analyzed with the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) transport model, supplemented by an event-by-event phase space coalescence model for deuteron and anti-deuteron production. The results are compared to data by the E866, E877, PHENIX, STAR and ALICE experiments. The B_2 values are calculated from the final spectra of protons and deuterons. At lower energies, sqrt{s_{NN}}le 20 GeV, B_2 drops drastically with increasing energy. The calculations confirm that this is due to the increasing freeze-out volume reflected in B_2sim 1/V. At higher energies, sqrt{s_{NN}}ge 20 GeV, B_2 saturates at a constant level. This qualitative change and the vanishing of the volume suppression is shown to be due to the development of strong radial flow with increasing energy. The flow leads to strong space-momentum correlations which counteract the volume effect.

Charged-particle spectra from μ− capture on Al

Published data on the emission of charged particles following nuclear muon capture are extremely limited. In addition to its interest as a probe of the nuclear response, these data are important for the design of some current searches for lepton flavor violation. This work presents momentum spectra of protons and deuterons following $\mu^{-}$ capture in aluminum. It is the first measurement of a muon capture process performed with a tracking spectrometer. A precision of better than 10% over the momentum range of 100--190 MeV/c for protons is obtained; for deuterons of 145--250 MeV/c the precision is better than 20%. The observed partial yield of protons with emission momenta above 80 MeV/c (kinetic energy 3.4 MeV) is $0.0322\pm0.0007(\text{stat})\pm0.0022(\text{syst})$ per capture, and for deuterons above 130 MeV/c (4.5 MeV) it is $0.0122\pm0.0009(\text{stat})\pm0.0006(\text{syst})$. Extrapolating to total yields gives $0.045\pm0.001(\text{stat})\pm0.003(\text{syst}) \pm 0.001(\text{extrapolation})$ per capture for protons and $0.018\pm0.001(\text{stat})\pm0.001(\text{syst})\pm 0.002(\text{extrapolation})$ for deuterons, which are the most precise measurements of these quantities to date.

Calculation of Particle Emissions and Fusion Cross Sections After 8B(t,*), 9B(t,*), and 10B(t,*) Reactions by Monte Carlo Simulations

Boron nuclide and tritium projectile interactions are considerable in terms of nuclear energy systems. This study aims to investigate the realization of the nuclear fusion reactions of the bombardment of boron nuclei with tritium. In addition, the 8B(t,*), 9B(t,*), and 10B(t,*) reactions have focused on the use of the resulting product particles in nuclear technology applications, particularly in nuclear medicine applications, in terms of energy and number. Tritium-induced reactions from boron isotopes (8B, 9B, and 10B) at 50 and 100 MeV were modeled by the GEANT4 and EMPIRE Monte Carlo codes. Gamma, alpha, tritium, deuteron, proton, and neutron emission spectra (GEANT4-10.3) were obtained, and cross sections per energy (EMPIRE-3.2-MALTA) were calculated. Fusion cross sections and 6Li and 7Li production cross sections, which are critical in thermonuclear fusion reactors as basic fusion reactions, are discussed based on the 8B(t,*), 9B(t,*), and 10B(t,*) reactions.

Multiplicity dependence of light (anti-)nuclei production in p–Pb collisions at [formula omitted] TeV

The measurement of the deuteron and anti-deuteron production in the rapidity range −1<y<0 as a function of transverse momentum and event multiplicity in p–Pb collisions at sNN = 5.02 TeV is presented. (Anti-)deuterons are identified via their specific energy loss dE/dx and via their time-of-flight. Their production in p–Pb collisions is compared to pp and Pb–Pb collisions and is discussed within the context of thermal and coalescence models. The ratio of integrated yields of deuterons to protons (d/p) shows a significant increase as a function of the charged-particle multiplicity of the event starting from values similar to those observed in pp collisions at low multiplicities and approaching those observed in Pb–Pb collisions at high multiplicities. The mean transverse particle momenta are extracted from the deuteron spectra and the values are similar to those obtained for p and Λ particles. Thus, deuteron spectra do not follow mass ordering. This behaviour is in contrast to the trend observed for non-composite particles in p–Pb collisions. In addition, the production of the rare He3 and He‾3 nuclei has been studied. The spectrum corresponding to all non-single diffractive p-Pb collisions is obtained in the rapidity window −1<y<0 and the pT-integrated yield dN/dy is extracted. It is found that the yields of protons, deuterons, and He3, normalised by the spin degeneracy factor, follow an exponential decrease with mass number.

Multiplicity dependence of (anti-)deuteron production in pp collisions at [formula omitted

In this letter, the production of deuterons and anti-deuterons in pp collisions at s=7 TeV is studied as a function of the charged-particle multiplicity density at mid-rapidity with the ALICE detector at the LHC. Production yields are measured at mid-rapidity in five multiplicity classes and as a function of the deuteron transverse momentum (pT). The measurements are discussed in the context of hadron–coalescence models. The coalescence parameter B2, extracted from the measured spectra of (anti-)deuterons and primary (anti-)protons, exhibits no significant pT-dependence for pT<3GeV/c, in agreement with the expectations of a simple coalescence picture. At fixed transverse momentum per nucleon, the B2 parameter is found to decrease smoothly from low multiplicity pp to Pb–Pb collisions, in qualitative agreement with more elaborate coalescence models. The measured mean transverse momentum of (anti-)deuterons in pp is not reproduced by the Blast-Wave model calculations that simultaneously describe pion, kaon and proton spectra, in contrast to central Pb–Pb collisions. The ratio between the pT-integrated yield of deuterons to protons, d/p, is found to increase with the charged-particle multiplicity, as observed in inelastic pp collisions at different centre-of-mass energies. The d/p ratios are reported in a wide range, from the lowest to the highest multiplicity values measured in pp collisions at the LHC.

Methods for separation of deuterons produced in the medium and in jets in high-energy collisions

Coalescence has long been used to describe the production of light (anti-)nuclei in heavy ion collisions. The same underlying mechanism may also exist in jets when a proton and a neutron are close enough in phase space to form a deuteron. We model deuteron production in jets by applying an afterburner to protons and neutrons produced in PYTHIA for $p$+$p$ collisions at a center of mass energy $\sqrt{s} =$ 7 TeV. PYTHIA provides a reasonable description of the proton spectra and the shape of the deuteron spectrum predicted by the afterburner is in agreement with the data. We show that the rise in the coalescence parameter $B_2$ with momentum observed in data is consistent with coalescence in jets. We show that di-hadron correlations can be used to separate the contributions from the jet and the underlying event. This model predicts that the conditional coalescence parameter in the jet-like correlation should be independent of the trigger momentum.

Characterization of a high repetition-rate laser-driven short-pulsed neutron source

We demonstrate a repetitive, high flux, short-pulsed laser-driven neutron source using a heavy-water jet target. We measure neutron generation at 1/2 kHz repetition rate using several-mJ pulse energies, yielding a time-averaged neutron flux of 2 × 105 neutrons s−1 (into 4π steradians). Deuteron spectra are also measured in order to understand source characteristics. Analyses of time-of-flight neutron spectra indicate that two separate populations of neutrons, ‘prompt’ and ‘delayed’, are generated at different locations. Gamma-ray emission from neutron capture 1H(n,γ) is also measured to confirm the neutron flux.

Spectral/target activity of short lived radio isotope in pulsed plasma accelerator

Accelerated deuteron spectra from magnetic spectrometry and graphite bombardment by such deuterons were used to produce short-lived radionuclides in NX2 plasma focus. The experiments show one order of magnitude difference between the activity generated by these techniques. The average activity of NX2 is 5.2 kBq and the highest activity for the best shot is about 40 kBq.

Measurement of deuteron spectra and elliptic flow in Pb\u2013Pb collisions at sqrt{s_{mathrm {NN}}} = 2.76 TeV at the LHC

The transverse momentum (p_mathrm{T} ) spectra and elliptic flow coefficient (v_{2}) of deuterons and anti-deuterons at mid-rapidity (|y|<0.5) are measured with the ALICE detector at the LHC in Pb–Pb collisions at sqrt{s_{mathrm {NN}}} = 2.76 TeV. The measurement of the p_mathrm{T} spectra of (anti-)deuterons is done up to 8 GeV/c in 0–10% centrality class and up to 6 GeV/c in 10–20% and 20–40% centrality classes. The v_{2} is measured in the 0.8 < p_mathrm{T} <~5 GeV/c interval and in six different centrality intervals (0–5, 5–10, 10–20, 20–30, 30–40 and 40–50%) using the scalar product technique. Measured pi ^{pm }, K^{pm } and p+overline{mathrm {p}} transverse-momentum spectra and v_{2} are used to predict the deuteron p_mathrm{T} spectra and v_{2} within the Blast-Wave model. The predictions are able to reproduce the v_{2} coefficient in the measured p_mathrm{T} range and the transverse-momentum spectra for p_mathrm{T} > 1.8 GeV/c within the experimental uncertainties. The measurement of the coalescence parameter B_2 is performed, showing a p_mathrm{T} dependence in contrast with the simplest coalescence model, which fails to reproduce also the measured v_{2} coefficient. In addition, the coalescence parameter B_2 and the elliptic flow coefficient in the 20–40% centrality interval are compared with the AMPT model which is able, in its version without string melting, to reproduce the measured v_{2}(p_mathrm{T} ) and the B_2(p_mathrm{T} ) trend.

Hybrid MHD/PIC simulation of a deuterium gas puff z pinch

We present the hybrid MHD/PIC simulations of the time evolution of a deuterium gas puff z pinch. Recent experiments with 3-MA current pinches [6] made in a novel configuration have shown that the neutron yields can reach 3.6×1012. It was shown that the observed neutron spectra could be explained by a suprathermal distribution of deuterons with a power law fall off in the ion energy distribution function at large energy. In order to perform the numerical simulation of gas puff z pinch a new hybrid model was developed. The described hybrid model treats the electrons as a massless fluid and ions as macroparticles. The macroparticle dynamic is calculated with the use of PIC method. Ion-ion Coulomb collision is considered with the use of MC method. In the model simulation, in the configuration close to described in [6], it was obtained the neutron yields up to 1.2×1012. Most neutrons are not thermonuclear. This level of the neutron yield is reached only when a strongly nonuniform neck-like constriction of z-pinch plasma occurs. In this case, the obtained deuteron spectra (with energy up to several tens MeV) have suprathermal high energy tail. These simulations demonstrate the utility of the developed hybrid model for the z-pinch simulation.

The method of deuteron spectra reconstruction in the PAMELA experiment

The method of reconstruction of the cosmic ray deuteron spectra is presented in this work. The data from the international space-born PAMELA experiment was analyzed. Deuterons in the energy range from 100 to 600 MeV/nucleon were selected by modified multiparameter correlation technique. This method can be used for obtaining the instrumental energy spectrum of deuterons.

Measurement of deuteron spectra and elliptic flow in Pb-Pb collisions at root s(NN)=2.76 TeV at the LHC

Measurement of deuteron spectra and elliptic flow in Pb-Pb collisions at root s(NN)=2.76 TeV at the LHC