Baryon Number Transfer Could Delay Quark–Hadron Transition in Cosmology
The National Institute of Astrophysics (INAF)— Astronomical Observatory of Trieste, Departmnet of Physics, University of Trieste, Via Tiepolo 11, Trieste 34143, Italy
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
Received: 14 October 2016 / Revised: 30 November 2016 / Accepted: 1 December 2016 / Published: 13 December 2016
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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Bonometto, S.A.; Mainini, R. Baryon Number Transfer Could Delay Quark–Hadron Transition in Cosmology. Universe 2016, 2, 32.
Bonometto SA, Mainini R. Baryon Number Transfer Could Delay Quark–Hadron Transition in Cosmology. Universe. 2016; 2(4):32.
Bonometto, Silvio A.; Mainini, Roberto. 2016. "Baryon Number Transfer Could Delay Quark–Hadron Transition in Cosmology." Universe 2, no. 4: 32.
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