Early Cosmological Period of QCD Confinement

If the strong coupling is promoted to a dynamical field-dependent quantity, it is possible that the strong force looked very different in the early Universe. We consider a scenario in which the dynamics is such that QCD confines at high temperatures with a large dynamical scale, relaxing back to ~1 GeV before big bang nucleosynthesis. We discuss the cosmological implications and explore potential applications, including fleshing out a new mechanism for baryogenesis which opens up if QCD confines before the electroweak phase transition of the Standard Model.Comment: v2: Matches the published versio

Baryogenesis via Particle-Antiparticle Oscillations

CP violation, which is crucial for producing the baryon asymmetry of the Universe, is enhanced in particle-antiparticle oscillations. We study particle-antiparticle oscillations (of a particle with mass O(100 GeV)) with CP violation in the early Universe in the presence of interactions with O(ab-fb) cross-sections. We show that, if baryon-number-violating interactions exist, a baryon asymmetry can be produced via out-of-equilibrium decays of oscillating particles. As a concrete example we study a $U(1)_R$-symmetric, R-parity-violating SUSY model with pseudo-Dirac gauginos, which undergo particle-antiparticle oscillations. Taking bino to be the lightest $U(1)_R$-symmetric particle, and assuming it decays via baryon-number-violating interactions, we show that bino-antibino oscillations can produce the baryon asymmetry of the Universe.Comment: 17 pages, 11 figures, refs added, typos fixe

Baryogenesis From Flavon Decays

Many popular attempts to explain the observed patterns of fermion masses involve a flavon field. Such weakly coupled scalar fields tend to dominate the energy density of the universe before they decay. If the flavon decay happens close to the electroweak transition, the right-handed electrons stay out of equilibrium until the sphalerons shut off. We show that an asymmetry in the right-handed charged leptons produced in the decay of a flavon can explain the baryon asymmetry of the universe

Long-lived biν\boldsymbol{\nu}o at the LHC

We examine the detection prospects for a long-lived bi$\nu$o, a pseudo-Dirac bino which is responsible for neutrino masses, at the LHC and at dedicated long-lived particle detectors. The bi$\nu$o arises in $U(1)_R$-symmetric supersymmetric models where the neutrino masses are generated through higher dimensional operators in an inverse seesaw mechanism. At the LHC the bi$\nu$o is produced through squark decays and it subsequently decays to quarks, charged leptons and missing energy via its mixing with the Standard Model neutrinos. We consider long-lived bi$\nu$os which escape the ATLAS or CMS detectors as missing energy and decay to charged leptons inside the proposed long-lived particle detectors FASER, CODEX-b, and MATHUSLA. We find the currently allowed region in the squark-bi$\nu$o mass parameter space by recasting most recent LHC searches for jets+MET. We also determine the reach of MATHUSLA, CODEX-b and FASER. We find that a large region of parameter space involving squark masses, bi$\nu$o mass and the messenger scale can be probed with MATHUSLA, ranging from bi$\nu$o masses of 10 GeV-2 TeV and messenger scales $10^{2-11}$ TeV for a range of squark masses.Comment: 15 pages, 4 figure