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In particle physics, strangeness (symbol S) [1] [2] is a property of particles, expressed as a quantum number, for describing decay of particles in strong and electromagnetic interactions that occur in a short period of time. The strangeness of a particle is defined as: = (¯) where n s
According to the IUPAP, the symbol s is the official name, while "strange" is to be considered only as a mnemonic. [2] The name sideways has also been used because the s quark (but also the other three remaining quarks) has an I 3 value of 0 while the u ("up") and d ("down") quarks have values of + 1 / 2 and − 1 / 2 respectively.
This gives new eigenvectors, which we can call K 1 which is the difference of the two states of opposite strangeness, and K 2, which is the sum. The two are eigenstates of CP with opposite eigenvalues; K 1 has CP = +1, and K 2 has CP = −1 Since the two-pion final state also has CP = +1, only the K 1 can decay this way.
The symbols encountered in these lists are: I , J (total angular momentum), P , u , d , s (strange quark), c (charm quark), b (bottom quark), Q , B (baryon number), S (strangeness), C , B ′ , as well as a wide array of subatomic particles (hover for name).
Mesons named with the letter "f" are scalar mesons (as opposed to a pseudo-scalar meson), and mesons named with the letter "a" are axial-vector mesons (as opposed to an ordinary vector meson) a.k.a. an isoscalar vector meson, while the letters "b" and "h" refer to axial-vector mesons with positive parity, negative C-parity, and quantum numbers I G of 1 + and 0 − respectively.
The η particles belong to the "pseudo-scalar" nonet of mesons which have spin J = 0 and negative parity, [9] [10] and η and η′ have zero total isospin, I, and zero strangeness, and hypercharge.
The strangeness quantum number S (not to be confused with spin) was noticed to go up and down along with particle mass. The higher the mass, the lower (more negative) the strangeness (the more s quarks). Particles could be described with isospin projections (related to charge) and strangeness (mass) (see the uds nonet figures).
Symbol Name Meaning SI unit of measure alpha: alpha particle: angular acceleration: radian per second squared (rad/s 2) fine-structure constant: unitless beta: velocity in terms of the speed of light c: unitless beta particle: gamma: Lorentz factor: unitless photon: gamma ray: shear strain: radian