It now has the spin and direction of a right-handed neutrino. But if you hold your left arm stationary and move your body to the right, your fist appears to move to the left. That is, the direction and spin (the curl of your fingers) are what a left-handed neutrino would have. If your body is stationary and your arm moves to the right, it’s still a left-handed neutrino. Imagine a left-handed neutrino by holding out your left fist. Helicity is not an unchangeable property it varies depending on how you look at the particle. Helicity is essentially what was described in the basic section: It’s how the spin relates to the motion of travel. Helicity is a property similar to spin, energy, or momentum-it is a conserved quantity, but it depends on the reference frame. The two terms often get interchanged, in part because there’s a lot of overlap. Despite helicity being the easier concept to understand, when scientists talk about neutrinos being left handed, they are probably talking about chirality. When scientists talk about handedness and neutrinos, they are actually talking about two different but related things: helicity and chirality. Other particles such as the quarks and the other three leptons (the electron, muon, and tau) have both left-handed and right-handed versions of both the matter particle and their antimatter partner. Once again, neutrinos turn out to be an anomaly. They have opposite spin (because your left fingers are curling clockwise and your right fingers are curling anticlockwise), but have the same direction of travel (which way your thumb is pointing). They have the same spin, represented by the direction your fingers curl, but have opposite directions of travel, represented by where your thumb points.Īnother demonstration: If you curl your hands into fists and extend your thumbs towards the ceiling, you’ll see examples of right-handed and left-handed particles. If you curl your hands into fists and extend your thumbs toward one another, you’ll see examples of right-handed and left-handed particles. It may seem odd to imagine particles as having “handedness.” Handedness refers to two properties of a particle: the direction of its spin and how it relates to the direction the particle is traveling. Symmetrically, all of the antineutrinos that scientists have ever seen have been right-handed. Southpaws will rejoice to hear that unlike in the human population, where left-handedness is not the norm, all the neutrinos that we have ever seen are in fact left-handed.
Just like people, neutrinos can be right-handed or left-handed.
0 kommentar(er)
