The nature of particles in the Standard Model vs String Theory

In summary, the Standard model says that atoms are composed of particles with physical dimensions (quarks and electrons), while String theory assumes that the zero-dimensional particles of the Standard model are not zero-dimensional entities but have a distinct size, although it's the smallest size that has any meaning - the Planck length - 1.6*10^-33cm.
  • #1
WaveJumper
771
1
Neutrinos are elementary particles that have the ability to pass through any matter. Billions of them pass through our bodies every second. Billions of them pass through the Earth and exit on the other side unaffected. They can pass through stars and travel to the other side of the universe. This is so mostly because they don't have an electrical charge and because atoms are 99.9999% empty space. Neutrinos have even the ability to pass through the nucleus of the atom or that 0.0001% that most physicists consider as the physical matter constituent of the atom, where more than 99% of atom's mass is concentrated. So, the ability of neutrinos to pass through 1 light year of lead belt is possible because the Standard model says the atom is not composed of particles with physical dimensions(quarks and electrons), but of zero-dimensional particles held together by subatomic nuclear forces - the strong force and electromagnetism, mediated by gluons and photons.

On the other hand, String theory assumes that the zero-dimensional particles of the Standard model are not zero-dimensional entities but have a distinct size, although it's the smallest size that has any meaning - the Planck length - 1.6*10^-33cm.

So my question is this - if String Theory were correct and strings had this almost physical size, how would at least some of the neutrinos passing through the Earth NOT collide at some point during their journey with the strings that compose matter(electrons, quarks, etc.)? If strings are energy/charge that allows neutrinos to pass through them, how can energy/charge have a physical size? Isn't that the reason why the Standard model "fell apart" at certain questions and couldn't give meaningful explanations?
 
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  • #2
WaveJumper said:
Neutrinos are elementary particles that have the ability to pass through any matter. Billions of them pass through our bodies every second. Billions of them pass through the Earth and exit on the other side unaffected. They can pass through stars and travel to the other side of the universe. This is so mostly because they don't have an electrical charge and because atoms are 99.9999% empty space. Neutrinos have even the ability to pass through the nucleus of the atom or that 0.0001% that most physicists consider as the physical matter constituent of the atom, where more than 99% of atom's mass is concentrated. So, the ability of neutrinos to pass through 1 light year of lead belt is possible because the Standard model says the atom is not composed of particles with physical dimensions(quarks and electrons), but of zero-dimensional particles held together by subatomic nuclear forces - the strong force and electromagnetism, mediated by gluons and photons.

Er.. I think you missed a very important point. Neutrinos interact with matter via the weak interactions and, to some extent, via gravitational interactions. But because such interactions are VERY weak (an electron neutrino barely has any mass, and therefore this interactions is, for all practical purposes, non-existent for neutrinos), this is why neutrinos do not interact with matter most of the time.

It has nothing to with with matter being mostly empty spaces. If that is true, then there would have been NO interaction of ANY kind, since everything is "empty spaces". What is more important is the nature of interactions that an elementary particle can have with other elementary particles.

Zz.
 
  • #3
you also have a classical picture of how particles interact, they don't interact as two tiny balls colliding (such as a micrscopic game of pool), the they interact over certain distances as well (just as celestial bodies interact over distance).

So before even thinking about comparing the standard model and string theory, you should get what elementary particle physics is and how particles and interactions are described in quantum physics.
 

1. What is the Standard Model?

The Standard Model is a widely accepted theory in particle physics that describes the fundamental particles and their interactions in the universe. It includes three of the four known forces (electromagnetic, strong, and weak) and explains the behavior of particles at the subatomic level.

2. How does the Standard Model explain the nature of particles?

The Standard Model categorizes particles into two groups: fermions and bosons. Fermions are particles that make up matter, such as quarks and electrons, while bosons are force-carrying particles, such as photons and gluons. It also explains the properties and interactions of these particles through the exchange of force-carrying particles.

3. What is String Theory?

String Theory is a theoretical framework that attempts to unify all four fundamental forces of nature by describing particles as tiny, one-dimensional strings instead of point-like particles. It also proposes the existence of extra dimensions beyond the three spatial dimensions we are familiar with.

4. How does String Theory differ from the Standard Model?

Unlike the Standard Model, String Theory attempts to explain the fundamental particles and their interactions in a single, unified framework that includes gravity. It also proposes the existence of extra dimensions and suggests that particles are not point-like but rather extended objects with a specific vibrational pattern.

5. Is one theory considered more valid than the other?

Both the Standard Model and String Theory have their strengths and limitations. The Standard Model has been extensively tested and confirmed through experiments, while String Theory is still a theoretical framework and has not yet been proven. Some scientists believe that String Theory may provide a more complete understanding of the universe, while others argue that it is currently untestable and therefore not a valid scientific theory.

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