The Meeting of Particle and Anti-Particle

Today I am beginning a long sequence of articles that will allow me to address some very basic and easily misunderstood concepts in physics: mass, energy, matter, force, and so on.  Along the way I will be dealing with some of the questions that readers have been asking me, such as whether mass and energy are or are not fundamentally the same; why the neutron is stable inside many atomic nuclei even though it decays when it is on its own; why the proton has a mass which is larger than those of the quarks that it contains; etc.  I’ve just completed the first link in this long chain, an article on the annihilation of particles with anti-particles.  I’ve described some (not all!) of the rules that govern this process, which is one of the most important in all of particle physics.  (You can also read a shorter and older article about anti-particles here.)

2 responses to “The Meeting of Particle and Anti-Particle

  1. hi matt,thank you for your sharing and creating a forum for the exchange of ideas,i have learnt much recently…stubborn as i am though i still believe the higgs particle must have negative mass,,and the decay of particles within the higgs field into photons gives me more reason to believe the higgs particle must be of negative mass…Am i right to assume the creation of photons,also means that the higgs produces light,therefore higgs particles appear before light,and so must be travelling faster,to stay ahead…as we all know,nothing can travel faster than the speed of light,because of the increase in mass…so the only way to stay ahead of lightspeed,and be able to produce light photons ,is by having negative mass…this is just something that ive been contemplating recently,and would love your thoughts,and or criticism…i also give another explanation on this by relating the mass of the higgs to the visiblity of glass….youll find it in my comments posted re a blog by Ed Milligan http://t.co/MZSpdE6,,,this is the link to the blog,look for my comments,again id love to hear your thoughts…i think its a better demonstration of the principle…cheers!!and thanks again

    • The decay of Higgs particles to two photons does not imply that the Higgs travels faster than light, or that it has negative mass.

      Positronium — an atom made from an electron and an anti-electron (or “positron”) orbiting each other — also decays to two photons. It obviously has positive mass (it is made from two objects of positive mass and has a very weak binding energy) and can obviously be brought to rest (because the experiments that look for positronium –> two photons do so by producing positronium at very small velocities).

      The Higgs, too, has positive mass, and positive mass-squared, and it travels below the speed of light.