Baryon number current

Because charge, baryon number, isospin, strangeness, etc. are all conserved by the strong interactions, combinations of u/s corresponding to these currents are exactly known. 

Lepton Family number (LF) or Lepton number (L) or Baryon number (B) violating modes, or/and A6 = 1 weak neutral current (Bl) modes... 

There is another alternative to SBBN which, although currently less favored, does have a venerable history BBN in the presence of a background of degenerate neutrinos. First, a brief diversion to provide some perspective. In the very early universe there were a large number of particle-antiparticle pairs of all kinds. As the baryon-antibaryon pairs... 

In keeping with the current interest in tests of conservation laws, we collect together a Table of experimental limits on all weak and electromagnetic decays, mass differences, and moments, and on a few reactions, whose observation would violate conservation laws. The Table is given only in the full Review of Particle Physics not in the Particle Physics Booklet. For the benefit of Booklet readers, we include the best limits from the Table in the following text. Limits in this text are for CL=90% unless otherwise specified. The Table is in two parts Discrete Space-Time Symmetries, i.e., C, P, T, CP, and CPT and Number Conservation Laws, i.e., lepton, baryon, hadronic flavor, and charge conservation. The references for these data can be found in the the Particle Listings in the Review. A discussion of these tests follows. 

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