Production of deuterons, tritons, He3 nuclei, and their antinuclei in pp collisions at s=

Abstract

Invariant differential yields of deuterons and antideuterons in pp collisions at √ s = 0.9, 2.76 and 7 TeV and the yields of tritons, 3 He nuclei, and their antinuclei at √ s = 7 TeV have been measured with the ALICE detector at the CERN Large Hadron Collider. The measurements cover a wide transverse momentum (p T ) range in the rapidity interval |y| < 0.5, extending both the energy and the p T reach of previous measurements up to 3 GeV/c for A = 2 and 6 GeV/c for A = 3. The coalescence parameters of (anti)deuterons and 3 He nuclei exhibit an increasing trend with p T and are found to be compatible with measurements in pA collisions at low p T and lower energies. The integrated yields decrease by a factor of about 1000 for each increase of the mass number with one (anti)nucleon. Furthermore, the deuteron-to-proton ratio is reported as a function of the average charged particle multiplicity at different center-of-mass energies.

Alternative coalescence model for deuteron, tritium, helium-3 and their antinuclei

“…The ALICE Collaboration measured the invariant differential yields of deuterons and antideuterons, E d 3 n dp 3 = 1 N inel 1 2πp T d 2 N dp T dy , (B.1) in inelastic proton-proton collisions at centre of mass energies √ s = 0.9, 2.76 and 7 TeV, in the p T range 0.8 < p T < 3 GeV and for rapidity 6 |y| < 0.5 [16]. Here E and p are the deuteron energy and momentum, N inel is the number of inelastic events, N is the total number of detected deuterons, and n ≡ N/N inel .…”

Nuclear coalescence from correlation functions

“…* Electronic address: kfir.blum@cern.ch 1 Also known as Hanbury Brown-Twiss (HBT) [3,4] analyses. 2 More practical details about the definition of R are given in Sec. IV.…”

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

“…Spectra Figure 2 shows the deuteron spectrum from PYTHIA with the coalescence afterburner compared to experimental measurements [15,23]. The deuteron spectrum from PYTHIA is scaled by a factor of 1/20.…”

“…It is expected that B 2 as a function of p T would be flat if the deuterons are formed via simple coalescence [15]. The rise in B 2 as a function of p T in data is suggested to be due to flow [15] and/or hard scattering [23,32]. The PYTHIA model does not include flow so the rise in B 2 as a function of p T in the PYTHIA+afterburner model can be attributed to hard scattering.…”

“…Deuteron production has been measured recently in pp collisions [15,23], an interesting data set to study production through coalescence. Measurements of antinuclei in pp collisions are helpful in searches for dark matter [24][25][26].…”