Quark clusters, QCD vacuum and the cosmological 7Li, Dark Matter and Dark Energy problems

Rachid Ouyed; Denis Leahy; Nico Koning; Prashanth Jaikumar

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arXiv · 2302.06820

Quark clusters, QCD vacuum and the cosmological 7Li, Dark Matter and Dark Energy problems

Rachid Ouyed·Denis Leahy·Nico Koning·Prashanth Jaikumar

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Abstract

We propose a non-exotic electromagnetic solution (within the standard model of particle physics) to the cosmological 7Li problem based upon a narrow 2 MeV photo-emission line from the decay of light Glueballs (LGBs). These LGBs form within color superconducting, tens of Fermi in size, quark clusters (SQCs) in the radiation-dominated post-BBN epoch. The mono-chromatic line from the LGB -> gamma+gamma decay reduces Big-Bang nucleosynthesis (BBN) 7Be by 2/3 without affecting other abundances or CMB physics, provided the combined mass of the SQCs is greater than the total baryonic mass in the Universe. Following the LGB emission, the in-SQC Quantum-ChromoDynamics (QCD) vacuum becomes unstable and "leaks" (via quantum tunnelling) into the external space-time (trivial) vacuum inducing a decoupling of SQCs from hadrons. In seeking a solution to the 7Li problem, we uncovered a solution which also addresses the dark energy (DE) and dark matter (DM) problem making these critical problems intertwined in our model. Being colorless, charge neutral, optically thin and transparent to hadrons, SQCs interact only gravitationally making them a viable CDM candidate. The quantum tunnelling of the in-SQC QCD vacuum to the trivial vacuum offers an explanation of DE in our model and allows for a cosmology which evolves into a LambdaCDM universe at low redshift with a possible resolution of the Hubble tension. Our model distinguishes itself by proposing that the QCD vacuum within SQCs possesses the ability to tunnel into the exterior trivial vacuum, resulting in the generation of DE. This implies the possibility that DM and hadrons might represent distinct phases of quark matter within QCD, characterized by different vacuum properties. We discuss SQC formation in heavy-ion collision experiments at moderate temperatures and the possibility of detection of MeV photons from LGB -> gamma+gamma.

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Rachid Ouyed, Denis Leahy, Nico Koning, Prashanth Jaikumar. 2023-02-14. Quark clusters, QCD vacuum and the cosmological 7Li, Dark Matter and Dark Energy problems. https://arxiv.org/abs/2302.06820

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