Can neutrinos pass through a quark

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Discussion Overview

The discussion centers on the behavior of neutrinos in relation to quarks, particularly focusing on the mechanisms that allow neutrinos to pass through matter, such as lead, without significant interaction. Participants explore the quantum-level interactions, or lack thereof, between neutrinos and quarks, touching on concepts from particle physics and the forces involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about how neutrinos can travel through vast amounts of lead without interacting, questioning what occurs at the quantum level when a neutrino encounters a quark.
  • Another participant explains that quarks are point particles and that the effective cross section for interactions is influenced by virtual gluons exchanged via the strong force, suggesting that it is the atomic structure that primarily affects neutrino interactions.
  • It is noted that a lone quark would not scatter a neutrino, and there are scenarios where a neutrino can be absorbed in a reaction similar to those that emit neutrinos.
  • A participant emphasizes that neutrinos should not be thought of as solid objects colliding with quarks, but rather as entities that may pass through without interaction due to the absence of force carriers.
  • Another participant compares the interaction of neutrinos with quarks to that of photons, stating that they can pass through each other without any interaction, challenging common intuitions about collisions and interactions.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the specifics of neutrino interactions with quarks, with multiple viewpoints presented regarding the nature of these interactions and the underlying quantum mechanics.

Contextual Notes

The discussion highlights the complexity of particle interactions and the role of force carriers, but does not resolve the nuances of how neutrinos interact with quarks or the implications of these interactions at a deeper level.

bland
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I am puzzled by the mechanism that enables neutrinos to be able to pass though many light years of lead without interacting with anything. I understand that they do not feel the strong force and that the weak force is slow to respond, but to travel straight though a 100 light year thick slab of lead, surely it not possible that they avoid everything. So what happens at the quantum level when a neutrino hits a quark square on? do they simply go straight through the quark?
 
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Quarks are point particles (as are neutrinos), no intrinsic size. Their effective cross section is mostly a result of the virtual gluons being exchanged (the strong force). It wouldn't really be quarks anyway that stop neutrinos, it would be the surrounding atomic structure as a whole (a lone quark would do nothing to scatter a neutrino). There are cases in which it can absorb a neutrino in a "somewhat analogous" reverse nuclear reaction to what emits a neutrino in the first place.

http://authors.library.caltech.edu/33286/1/BAHpr64d.pdf
http://www.physics.ox.ac.uk/neutrino/Petyt/chapter2.pdf
 
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OK, thanks for that reply and the pdf's.
 
Well, you shouldn't think of neutrinos as balls striking the quarks...
Things are way more complicated. Since interactions mainly occur by the mediation of force carriers, then if there is no force carrier there is no interaction, even if the particle goes through the other...Interactions are then connected to probabilities, with the weak being the less probable (because of the heavy gauge bosons).
 
bland said:
So what happens at the quantum level when a neutrino hits a quark square on? do they simply go straight through the quark?

The same as when a photon hits another photon - nothing happens. They go through each other as if nothing was there.

Particles are not tiny ball bearings. Your intuition says "when things collide, they bounce off or otherwise interact ('rock shatters glass' etc)". Your intuition comes from your everyday experience with baryonic matter. In general, it's wrong: when things collide, they MAY interact, but don't necessarily interact.
 
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