Baryon Number Transfer Could Delay Quark–Hadron Transition in Cosmology
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The National Institute of Astrophysics (INAF)— Astronomical Observatory of Trieste, Departmnet of Physics, University of Trieste, Via Tiepolo 11, Trieste 34143, Italy
2
Department of Physics G. Occhialini, Milano-Bicocca University, Piazza della Scienza 3, Milano 20126, Italy
*
Author to whom correspondence should be addressed.
Academic Editors: Roman Pasechnik, José Eliel Camargo-Molina and António Pestana Morais
Universe 2016, 2(4), 32; https://doi.org/10.3390/universe2040032
Received: 14 October 2016
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Revised: 30 November 2016
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Accepted: 1 December 2016
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Published: 13 December 2016
(This article belongs to the Special Issue Quark-Gluon Plasma in the Early Universe and in Ultra-Relativistic Heavy-Ion Collisions)
In the early Universe, strongly interacting matter was a quark–gluon plasma. Both lattice computations and heavy ion collision experiments, however, tell us that, in the absence of chemical potentials, no plasma survives at MeV. The cosmological Quark–Hadron transition, however, seems to have been a crossover; cosmological consequences envisaged when it was believed to be a phase transition no longer hold. In this paper, we discuss whether even a crossover transition can leave an imprint that cosmological observations can seek or, vice versa, if there are questions cosmology should address to QCD specialists. In particular, we argue that it is still unclear how baryons (not hadrons) could form at the cosmological transition. A critical role should be played by diquark states, whose abundance in the early plasma needs to be accurately evaluated. We estimate that, if the number of quarks belonging to a diquark state, at the beginning of the cosmological transition, is , its dynamics could be modified by the process of B-transfer from plasma to hadrons. In turn, by assuming B-transfer to cause just mild perturbations and, in particular, no entropy input, we study the deviations from the tracking regime, in the frame of SCDEW models. We find that, in some cases, residual deviations could propagate down to primeval nuclesynthesis.
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MDPI and ACS Style
Bonometto, S.A.; Mainini, R. Baryon Number Transfer Could Delay Quark–Hadron Transition in Cosmology. Universe 2016, 2, 32. https://doi.org/10.3390/universe2040032
AMA Style
Bonometto SA, Mainini R. Baryon Number Transfer Could Delay Quark–Hadron Transition in Cosmology. Universe. 2016; 2(4):32. https://doi.org/10.3390/universe2040032
Chicago/Turabian StyleBonometto, Silvio A., and Roberto Mainini. 2016. "Baryon Number Transfer Could Delay Quark–Hadron Transition in Cosmology" Universe 2, no. 4: 32. https://doi.org/10.3390/universe2040032
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