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Anirvan Shukla

Publications and source records attributed to Anirvan Shukla.

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First measurements of deuteron production spectra in p+p collisions at beam momentum of 158 GeV/c at NA61/SHINE

The NA61/SHINE spectrometer at the CERN Super Proton Synchrotron (SPS) scans particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range towards various physics goals. This paper presents the first differential production measurements of deuterons at energies relevant for cosmic-ray studies, produced in inelastic p+p interactions at incident projectile momentum of 158 GeV/c ($\sqrt{s}$ = 17.3 GeV). The double-differential spectra are presented as functions of rapidity and transverse momentum and are compared to predictions of the thermal and coalescence models. These measurements are essential for improving our understanding of cosmic (anti)nuclei production, as detecting cosmic antinuclei can be a breakthrough approach to identifying dark matter. The primary source of cosmic antinuclei background is interactions between cosmic-ray protons and interstellar hydrogen gas. Gaining a deeper insight into the deuteron production mechanism in p+p interactions is an essential first step in modeling cosmic antinuclei production.

nucl-ex

Reevaluation of the cosmic antideuteron flux from cosmic-ray interactions and from exotic sources

Cosmic-ray antideuterons could be a key for the discovery of exotic phenomena in our Galaxy, such as dark-matter annihilations or primordial black hole evaporation. Unfortunately the theoretical predictions of the antideuteron flux at Earth are plagued with uncertainties from the mechanism of antideuteron production and propagation in the Galaxy. We present the most up-to-date calculation of the antideuteron fluxes from cosmic-ray collisions with the interstellar medium and from exotic processes. We include for the first time the antideuteron inelastic interaction cross section recently measured by the ALICE collaboration to account for the loss of antideuterons during propagation. In order to bracket the uncertainty in the expected fluxes, we consider several state-of-the-art models of antideuteron production and of cosmic-ray propagation.

astro-ph.HE

Large-scale Simulations of Antihelium Production in Cosmic-ray Interactions

The possibility of antihelium production in interaction of cosmic rays with the interstellar gas is studied using large-scale Monte Carlo simulations. For this purpose, an energy-dependent coalescence mechanism developed previously is extended to estimate the production of light antinuclei (${}^3\overline{\text{He}}$ and ${}^4\overline{\text{He}}$). The uncertainty in the coalescence parameter and its effect on the expected antiparticle flux is also investigated. The simulated background antihelium fluxes are found to be lower than the fluxes predicted by simplified models using numerical scaling techniques.

astro-ph.HE

Deuteron and Antideuteron Production Simulation in Cosmic-ray Interactions

The study of the cosmic-ray deuteron and antideuteron flux receives an increasing interest in current astrophysics investigations. For both cases an important contribution is expected from the nuclear interactions of primary cosmic rays with intergalactic matter. In this work, deuteron and antideuteron production from 20 to 2.6$\times$10$^{7}$ GeV beam energy in p+p and p+A collisions were simulated using EPOS-LHC and Geant4's FTFP-BERT Monte Carlo models by adding an event-by-event coalescence model afterburner. These estimates depend on a single parameter ($p_0$) obtained from a fit to the data. The $p_0$ for deuterons in this wide energy range was evaluated for the first time. It was found that $p_0$ for antideuterons is not a constant at all energies as previous works suggested and as a consequence the antideuteron production cross section can be at least 20 times smaller in the low collision energy region, than earlier estimations.

astro-ph.HE