Heat the oil in a large Dutch oven over medium heat. Add the onion and bell pepper and cook, stirring occasionally, until slightly softened, about 4 to 5 minutes. Add the garlic and cook, stirring, until fragrant, about 1 minute more.

Add the ground beef and cook, breaking up meat with a spoon, until no longer pink, about 5 minutes. Drain any excess grease and return the pot to low heat.

Add the tomato paste and Worcestershire sauce and stir it into the meat mixture. Sprinkle the chili powder, cumin, dry mustard, oregano, salt and pepper over the mixture and stir until well combined. Allow the mixture to cook over low heat for a minute or two.

Add the beef broth, crushed tomatoes, brown sugar, and beans. Increase the heat as needed to bring the chili to a boil, then reduce the heat to low, cover and simmer for 45 minutes, stirring occasionally.

Uncover and continue to simmer for an additional 10 to 15 minutes, or until it reaches the desired thickness.