# The arduous quest to find the shape of the electron’s charge

- July 26, 2023
- Posted by: OptimizeIAS Team
- Category: DPN Topics

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**The arduous quest to find the shape of the electron’s charge**

**Subject : Science and technology**

**Section: Msc**

**Concept :**

- Physicists use extreme precision tests to search for flaws in the Standard Model. A new study used a strong electric field in a molecule to measure the electric dipole moment of its valence electrons, and concluded by
**finding no evidence of ‘new physics’.** - The result precludes the existence of certain hypothetical particles

**Standard Model of Elementary Particle Physics**

- The standard model of elementary particles is a theoretical construct in physics that describes particles of matter and their interaction.
- It describes the elementary particles of the world as being connected by mathematical symmetry, just as two objects are connected by bilateral (left-right) symmetry.
- These are mathematical groups generated by continuous transformations from, say, one particle to another.
- According to this model there are a finite number of fundamental particles which are represented by the characteristic “eigen” states of these groups.
- The particles predicted by the model, such as the Z boson, have been seen in experiments.
- The last to be discovered, in 2012, was the Higgs boson which gives mass to the heavy particles.

**Why is the Standard Model believed to be Incomplete?**

- Because it gives a unified picture of only three of the four fundamental forces of nature — electromagnetic, weak nuclear, strong nuclear and gravitational interactions — it totally omits gravity.
- So, in the grand plan of unifying all forces so that a single equation would describe all the interactions of matter, the standard model was found to be lacking.
- Also, it does not include a description of dark matter particles.
- So far these have been detected only through their gravitational pull on surrounding matter.

**How are the Symmetries related to Particles**?

- The symmetries of the standard model are known as gauge symmetries, as they are generated by “gauge transformations”.
- Gauge transformations are a set of continuous transformations (like rotation is a continuous transformation). Each symmetry is associated with a gauge boson.
- For example, the gauge boson associated with electromagnetic interactions is the photon. The gauge bosons associated with weak interactions are the W and Z bosons. There are two W bosons — W+ and W-.