Antideuteron Production Research Articles

Deuteron and antideuteron measurements in Au + Au collisions at $\sqrt{s_{NN}}=200~\mbox{GeV}$ at RHIC-PHENIX

In Run-7 of RHIC operations PHENIX has recorded over 5.4 billion minimum bias events, facilitating a detailed study of deuteron and antideuteron production as a function of centrality and up to transverse momentum of pT=5 GeV/c. We present transverse momentum pT and transverse mass mT spectra, mean transverse momentum 〈pT〉, source parameters, particle ratios, and nuclear modification factor RCP. Deuteron and antideuteron spectra are compared to those of other identified particles and to hydrodynamical predictions.

Deuteron and anti-deuteron production in e+e− collisions at the Z resonance

Deuteron and anti-deuteron production in Z decays has been observed in the ALEPH experiment at LEP. The production rate of anti-deuterons is measured to be 5.9+-1.8+-0.5 10^-6 per hadronic Z decay in the anti-deuteron momentum range 0.62 to 1.03 GeV/c. The coalescence parameter B_2, which characterizes the likelihood of anti-deuteron production, is measured to be 0.0033+-0.0013 GeV^2 in Z dedays. These measurements indicate that the production of anti-deuterons is suppressed in e+e- collisions compared to pp and photoproduction collisions.

PRODUCTION OF LIGHT ANTINUCLEI IN HEAVY-ION COLLISIONS

The antideuteron and antihelium-3 production rates in high-energy heavy-ion collisions are calculated in the framework of fusion mechanism. It is supposed that [Formula: see text] participating in the fusion are moving in the mean field of other fireball constituents. It is demonstrated that at high energies, where many pions are present in the fireball, the number of produced [Formula: see text] and [Formula: see text] is determined by the balance between created and disintegrated (mainly in collisions with pions) [Formula: see text] and [Formula: see text]. The explicit formulae for coalescence parameters are presented and compared with the data.

Measurement of anti-deuteron photoproduction and a search for heavy stable charged particles at HERA

The cross section for anti-deuteron photoproduction is measured at HERA at a mean centre-of-mass energy of W_{\gamma p} = 200 GeV in the range 0.2 < p_T/M < 0.7 and |y| < 0.4, where M, p_T and y are the mass, transverse momentum and rapidity in the laboratory frame of the anti-deuteron, respectively. The numbers of anti-deuterons per event are found to be similar in photoproduction to those in central proton-proton collisions at the CERN ISR but much lower than those in central Au-Au collisions at RHIC. The coalescence parameter B_2, which characterizes the likelihood of anti-deuteron production, is measured in photoproduction to be 0.010 \pm 0.002 \pm 0.001, which is much higher than in Au-Au collisions at a similar nucleon-nucleon centre-of-mass energy. No significant production of particles heavier than deuterons is observed and upper limits are set on the photoproduction cross sections for such particles.

Threshold corrections in bottom and charm quark hadroproduction at next-to-next-to-leading order

The cross section for anti-deuteron photoproduction is measured at HERA at a mean centre-of-mass energy of W_{\gamma p} = 200 GeV in the range 0.2 < p_T/M < 0.7 and |y| < 0.4, where M, p_T and y are the mass, transverse momentum and rapidity in the laboratory frame of the anti-deuteron, respectively. The numbers of anti-deuterons per event are found to be similar in photoproduction to those in central proton-proton collisions at the CERN ISR but much lower than those in central Au-Au collisions at RHIC. The coalescence parameter B_2, which characterizes the likelihood of anti-deuteron production, is measured in photoproduction to be 0.010 \pm 0.002 \pm 0.001, which is much higher than in Au-Au collisions at a similar nucleon-nucleon centre-of-mass energy. No significant production of particles heavier than deuterons is observed and upper limits are set on the photoproduction cross sections for such particles.

Formation of antideuterons in heavy-ion collisions

The antideuteron production rate at high-energy heavy ions collisions is calculated basing on the concept of anti-d formation by antinucleons which move in the mean field of the fireball constituents (mainly pions). The explicit formula is presented for the coalescence parameter B_2 in terms of deuteron binding energy and fireball volume.

ANTIDEUTERON PRODUCTION AND THE PHYSICS OF COALESCENCE: IMPLICATIONS OF A NEW APPROACH

Within the framework of coalescence model, the problem of antideuteron [Formula: see text] production in some high energy nuclear collisions has here been studied with the help of a new combination of models (NCM) outlined in some detail in the text. The totality of the approach, including one useful parametrization, adopted here leads us to obtain finally some theoretical results which are modestly in agreement with the measured data on various aspects of antideuteron production in both Pb + Pb and Au + Au collisions at moderately high energies. The implications of all this are discussed at the end of the paper.

Antideuteron production in proton-proton and proton-nucleus collisions

The experimental data of the antideuteron production in proton-proton and proton-nucleus collisions are analyzed within a simple model based on the diagrammatic approach to the coalescence model. This model is shown to be able to reproduce most of the existing data without any additional parameter.

Coalescence and flow in ultrarelativistic heavy ion collisions

Using a density matrix approach to describe the process of coalescence, we calculate the coalescence probabilities and invariant momentum spectra for deuterons and antideuterons. We evaluate our expressions with a hydrodynamically motivated parametrization for the source at freeze-out which implements rapid collective expansion of the collision zone formed in heavy ion collisions. We find that the coalescence process is governed by the same lengths of homogeneity which can be extracted from HBT interferometry. They appear in the absolute cluster yield via an effective volume factor as well as in a quantum mechanical correction factor which accounts for the internal structure of the deuteron cluster. Our analysis provides a new interpretation for the parameters in the popular phenomenological coalescence model and for the effective overlap volume in Hagedorn's model for cluster production in pp collisions. Using source parameters extracted from a recent HBT analysis of two-pion correlations, we successfully describe deuteron and antideuteron production data from Pb+Pb collisions at the CERN SPS as measured by the NA44 and NA52 collaborations. We also confirm the recent finding by Polleri et al. that the different measured slopes of nucleon and deuteron transverse mass spectra require a transverse density profile of the source which is closer to a box than to a Gaussian shape.

Antideuteron production in high energy heavy ion collisions.

Experiment E858 at the Brookhaven National Laboratory Alternating Gradient Synchrotron has recently reported the detection of two antideuterons produced in $14.6A$ GeV/c Si + Au collisions. The data were interpreted as implying antideuteron production rates about an order of magnitude below expectations. We use an extended RQMD model to demonstrate that the antideuteron yields are readily explained in a dynamical scenario that includes collective expansion and strong antinucleon absorption.

Antinucleon sources in heavy-ion collisions

As recently measured in relativistic heavy-ion collisions, the antideuteron formation rate, which is the ratio of the antideuteron production cross section to the antiproton cross section squared at the same momentum per nucleon, is substantially smaller than the formation rate of deuterons. This happens because the shape of the antinucleon source is different from the nucleon one. In the case of baryon-rich sources, the nucleons are emitted from the whole source volume while antinucleons are emitted predominantly from the surface due to antinucleon absorption in the baryon environment.

On the feasibility of antideuteron production and storage at CERN

The new Antiproton Accumulator Complex is now in operation at CERN. We consider the possibility of using this facility to create and store antideuterons and conclude that we could achieve an accumulation rate of about 2·106 particles/day. No major rebuild of the rings is envisaged, but it is thought that modification to existing components and becoming operational would take about 5 to 6 months. We stress, however, that the operation of such a facility and the use of any stack of antideuterons for particle physics would be extremely taxing.