Is there any particle smaller than a proton,if so,describe it ?

Question

atom

Answer 1

An electron is much smaller and has approximate 1/1800 as much mass as a proton.

Answer 2

Elemetary particles do not have size, that is their size is zero. It means that elementary particle is fully described by its coordinate and spin. In quatum mechanics particles are delocalized, still they have zero size, their wave function depends only on the above mentioned coordinates:

ψ = ψ(x,y,z,s)

Proton is not elementary particle, because its coordinate is insufficeint to fully describe a proton. Protons have internal structure, and therefore they have non-zero size.

The electron is elemantary particle, and it has the smallest rest mass among all massive particles. Neutrino is considered massles, but there are some indications that neutrinos may have tiny non-zero mass.

Answer 3

Most fundamental particles are smaller than a proton.  The only ones that aren't are pretty exotic and not found too often.

The three most common quarks (including the two kinds that make up the proton and neutron) are smaller.

All the leptons (including electrons) except the tau are smaller.

Photons, gluons, and gravitons are presumably massless, and therefore smaller.

As for composite particles, some of the mesons (including pions, the most common) are lighter than a proton as well.

Answer 4

Quarks, leptons, mesons, there are many of them.

The smallest ones are the quarks and the leptons. They are elementary particles. Protons consist of three quarks, two up quarks and a down quark.

Answer 5

The Quark just for starters.  3 quarks make a proton and 3 quarks make a neutron, so how do they know which particle to make?  Well one is 2 up quarks and one down quark and the other is 1 up & 2 downs but I don't remember which way round and as they have never been isolated (to my knowledge) it makes them hard to describe but they have other members of the family as well: Strange, Charmed, Truth & Beauty are all whimsical names the other flavours have been given and we haven't even touched on mesons, muons and gluons yet!