Grand unification and baryon number violation

4 problems

• Do the SM gauge forces unify into a single group?

  Open

  The strengths of the three forces change with energy and nearly meet near $1e16\, \mathrm{GeV}$. Whether they truly become one force is unknown.

• Do neutrons oscillate into antineutrons?

  Open

  Some theories allow a neutron to turn into its own antiparticle, changing baryon number by two. This would not show up in proton decay searches.

• Does the proton decay to an antineutrino and a kaon?

  Open

  Supersymmetric unified theories favor a different decay of the proton, into an antineutrino and a charged kaon. Detecting the kaon needs detectors with good tracking.

• Is the proton lifetime to $e+ \pi0$ below $1e35\,\mathrm{years}$?

  Open

  Grand unified theories predict a proton can decay into a positron and a neutral pion. Huge water detectors watch for this rare event.