Particles and antiparticles have the same mass and lifetime. They each decay into equal particles with opposite charges. Not so these particles. Their lifetimes are very different and their decays prove that they are two completely different particles.
K0S → 2 π0
K0L → π- + μ+
K0L → π+ + μ-
Analysis of the decays shows that the K0S consists of two uncharged pions [ 2 π0 ] and the K0L consists of a muon and a charged pion: [ π- μ+ ] or [ π+ μ- ]. The K0L is a particle-antiparticle pair and the uncharged kaons form a particle triplet.
Kaons are a specific type of meson (mesons are particles made of one quark and one antiquark). What makes kaons unique is that they are made of one up quark or down quark, and one strange quark. (One of the two quarks that make of a kaon must be an antiquark, and the other must be normal matter.
In particle physics, a kaon , also called a K meson and denoted K ,[a] is any of a group of four mesons distinguished by a quantum number called strangeness. In the quark model they are understood to be bound states of a strange quark (or antiquark) and an up or down antiquark (or quark).Kaons have proved to be a copious source of information on the nature of fundamental interactions since their discovery in cosmic rays in 1947
Kaons have played a distinguished role in our understanding of fundamental conservation laws: CP violation, a phenomenon generating the observed matter–antimatter asymmetry of the universe, was discovered in the kaon system in 1964
The four kaons are :
As the quark model shows, assignments that the kaons form two doublets of isospin; that is, they belong to the fundamental representation of SU(2) called the 2. One doublet of strangeness +1 contains the K+ and the K0 . The antiparticles form the other doublet (of strangeness −1).
Good question,
Effectively K_S (K_Short) and K_L(Long) are not particle antiparticle pair they are gauge eigenstates and antiparticles of themselves. While K0 and K0_bar are eigenstates of another gauge and form particle-antiparticle pair as pointed out by Hadi Jabbar Alagealy .
Dear Hadi Jabbar Alagealy !
First of all, thank you for your detailled answer.
If I understand the quark theory right, than have the two neutral Kaons the structures: K0 (d; anti-s) and Anti-K0 (anti-d; s). Which is the K0S and which is the K0L? The same properties with opposite 'sign' would be expected. But both particles have very different properties. The above mentioned decays are only one example.
All decays and particle showers eventually end in electrons, positrons and energy. A 'quark' has never been observed.
If one starts from the observed facts, then particles are more or less stable combinations of electrons and positrons under accumulation of high amounts of energy. Some of these assemblies are stable: the protons and atomic nuclei.
For the neutral Kaons, the analysis yields the following:
Their elementary structure is (2e+ 2e-).
Their substructures show a triplett:
K0S (π0 π0)
K0L (π+ μ-) and Anti-K0L (π- μ+)
Supplement: Elementary structure of the charged pions (2e+ 1e-) and (1e+ 2e-).
The muons (e+)* and (e-)*
Thesis The Justification of a realistic Picture of Particles and At...
The mass (physical) eigenstates K_S and K_L are linear combinations of the flavor eigenstates K^0 and K^0bar. It was thought that K_S and K_L are CP eigenstates, and that K_S decays only to 2 pions and that K_L decays only to 3 pions (so K_S is CP-even and K_L is CP-odd). So CP was considered as a good symmetry, and the mass eigenstates were the same as the CP eigenstates. However, after the discovery of CP violation (1964 Christenson at al. discovered the decay of K_L to 2 pions), K_L and K_S are no longer considered as CP-eigenstates. But since the CP violation is very tiny in the kaon system, it is still a good approximation to consider K_S as CP-even and K_L as CP-odd. Therefore These 2 particles are approximately their own antiparticles. In other words, K_S and K_L are not particle and antiparticle; unlike K^0 and K^bar (K^0bar is tha antiparticle of K^0 and vice versa).
Wafia Bensalem
Thanks also for your reply.
In accordance with all observations, particles and nuclei can be represented as combinations of positrons and electrons. There are much more combinations (=particles) than the 'quarks' allow. So the discovery of new particles need not be a reason for scientific dispute, as happened.
The present theoretical particle physics has no basis (where are the 'quarks'?), but many theory-born language rules like "it is its own antiparticle", which cover the dilemma, but do not solve it.
The uncharged pion has the elementary structure (e+ e-). To say "it is its own antiparticle" (language regulation) does not reflect the truth. The charged pions have the elementary structure (2e+ e-) and (e+ 2e-). An unambiguous inverse structure and therefore particle and ant-particle.
The light mesons already discovered in the 1930s and 1940s are the subparticles from which all nuclei and heavy particles are built up. The light mesons themselves are formed by positrons and electrons in different number ratios.
If one has recognized the actual construction plan of the matter, one is very surprised about the fact that the smartest heads hold on to 50 or 100 year old theoretical fantasies.
I refer again to the publication in which the basic features of a realistic particle physics are summarized. Thesis The Justification of a realistic Picture of Particles and At...
l am afraid to say that pions are not made of electrons and positrons I remember also that someone had said that photons are electons and positrons too the simple reason and which everyone must have in mind is symmetries and thus conservation laws. In short, the lepton number is a conserved second pions strongly interact while electrons don't, more subtle but very profound, because of the triviality problem(or disease) which strong interactions thankfully doesn't have; while QED suffer from.
Have a Good day
Faical Barzi
Look at the decay behaviour of the uncharged pion:
(1) π0 → γ (98,8%)
(2) π0 → e+ + e− (1,2%)
This is almost identical to the decay of a positronium, only more energy is released because of the greater mass of the π0. Every decay, every particle shower ends in positrons, electrons and energy and never in 'quarks'.
I cannot understand why particle physics clings to the invented 'quarks'. Even the detection of these particles with the LHC finally failed in 2016.
The world of particles is something completely different from what particle physics imagines and describes in its theories.
Dear Hans-G. Hildebrandt ,
Free quarks are "confined" : only color neutral bound states of quarks are observable no free quarks are observable.