Strange Quark
Composition :
Statistics :
Generation :
Family :
Interaction forces :
Symbol :
Antiparticle :
Mass :
Decays into :
Electric charge :
Color charge
Spin :
Weak isospin :
Weak hypercharge :
Elementary particle
Fermionic
Second
Quark
strong, weak,
electromagnetic force
gravity
s
Strange Antiquark ( s )
95 MeV/c²
up quark
-¹/₃ e
Yes
¹/₂
LH : - ¹/₂, RH : 0
LH : + ¹/₃, RH : +²∕₃
_
+ 9
- 3
STRANGE QUARK
Definition
The strange quark is a type of elementary particle that belongs to the family of quarks. It is the third lightest quark and is found in subatomic particles called hadrons. The presence of a strange quark in a particle is denoted by a quantum number S=-1.
Properties of the Strange Quark:
Symbol: The symbol used to represent the strange quark is "s".
Electric Charge: The strange quark has an electric charge of -1/3 e.
Mass: The bare mass of the strange quark is approximately 95+9−3 MeV/c^2.
Spin: Like all quarks, the strange quark is an elementary fermion with a spin of ½.
Interactions: The strange quark experiences all four fundamental interactions: gravitation, electromagnetism, weak interactions, and strong interactions.
Antiparticle: The antiparticle of the strange quark is the strange antiquark, which has properties that are equal in magnitude but opposite in sign.
Quantum State of the Strange Quark:
Strangeness Quantum Number: The strangeness of a particle is a quantum number that describes the presence of strange quarks and strange antiquarks. It is defined as S = -(n_s - n_s¯), where n_s represents the number of strange quarks and n_s¯ represents the number of strange antiquarks.
Conservation of Strangeness: Particle decay by the strong or electromagnetic interactions preserves the strangeness quantum number. This conservation law helps in understanding and interpreting the decay processes of particles involving strange quarks.
Combinations with Strange quarks
Mesons with Strange Quarks:
Mesons are hadrons composed of a quark and an antiquark. When a strange quark combines with an antiquark of another flavor, it forms a meson with strangeness. Examples include:
K-mesons (Kaons): These are the most well-known mesons containing strange quarks. Kaons exist in various charge states (K⁺, K⁰, K⁻) and have different quark compositions. The K- Kaon has a strange quark :
K- Kaon
K-0 Kaon
B-mesons :
B0s-meson
D-mesons :
D-s meson
Phi-mesons
Φ+ meson
Baryons with Strange Quarks:
Baryons are hadrons composed of three quarks. When a strange quark combines with two other quarks, it forms a baryon with strangeness. Examples include:
Lambda Baryon (Λ): The lambda baryon contains one up, one down, and one strange quark (u-d-s). It is electrically neutral and has a non-zero strangeness quantum number.
The lambda baryon (Λ) (Fig. 124)
Sigma Baryons (Σ): Various sigma baryons exist, and some of them contain strange quarks.
Sigma with JP = -1/2 (Sigma Baryons Σ⁺, Σ0 and Σ⁻) (Fig. 125)
Sigma with JP = 3/2
These baryons have the same quark configurations as the Sigma baryons with JP = -1/2, but are indicated with the symbols Σ*⁺, Σ*0 and Σ*⁻
Xi-Baryons
Xi Baryons Ξ0 and Ξ⁻
Omega (Ω) baryons
There is also the double bottom Omega baryon with the quark configuration sbb
Exotic Hadrons:
Exotic hadrons are particles that do not fit the traditional quark-antiquark or three-quark baryon models. Some exotic hadrons have been proposed to contain strange quarks, but their existence and properties are still subjects of ongoing research.
Strange Quark Matter:
In extreme conditions of high temperature and pressure, such as those believed to exist in the cores of neutron stars, strange quarks may combine to form strange quark matter, which is a hypothetical state of matter composed almost entirely of strange quarks. The existence of strange quark matter is still a topic of theoretical research and debate.
Figure 117 - K- Kaon
Figure 118 – K0 Kaon
Figure 119 - B0s meson
Figure 120 - meson
Figure 121 – Φ+ meson
Figure 123 - Sigma Baryons Σ⁺, Σ0 and Σ⁻
Figure 122 - The lambda baryon (Λ)
Figure 124 - Xi Baryons Ξ0 and Ξ⁻
Figure 125 - Xi Baryons
Figure 126 - Omega Baryons
Creation of strange quarks
The creation of strange quarks can occur through various processes in high-energy environments, often involving particle collisions and interactions. Here are some key processes leading to the creation of strange quarks:
Hadronization in High-Energy Collisions:
Input Particles: High-energy protons, heavy ions, or other particles involved in collisions.
Forces: The strong nuclear force mediated by gluons.
Output Particles: In the extreme conditions of high-energy collisions, quarks and gluons are liberated from their confined state within protons and neutrons. This phase is called hadronization, leading to the formation of a hot and dense medium known as the quark-gluon plasma.
Strangeness Creation: The high temperatures and energy densities during hadronization allow for processes that change the flavor of quarks, including the creation of strange quarks.
Strangeness-Changing Weak Decays:
Input Particles: Hadrons containing up, down, or charm quarks.
Forces: Weak nuclear force.
Output Particles: Hadrons with changed quark composition, possibly containing strange quarks.
Strangeness Creation: Weak interactions can change the flavor of quarks, converting non-strange quarks into strange quarks. For example, processes like the decay of a charmed meson can result in the creation of strange quarks.
Hyperon Production:
Input Particles: High-energy collisions involving protons or other baryons.
Forces: Strong nuclear force.
Output Particles: Hyperons, which are baryons containing strange quarks.
Strangeness Creation: The high energy in collisions can lead to the creation of hyperons, which inherently contain strange quarks. The production of hyperons is a direct way to create strange quarks in the final-state particles.
Resonance Excitation and Decay:
Input Particles: Hadrons or other particles involved in collisions.
Forces: Strong nuclear force.
Output Particles: Resonance states that can subsequently decay into particles containing strange quarks.
Strangeness Creation: Resonance states can be excited during high-energy processes, and their subsequent decay can produce particles with strange quarks. The intermediate resonance state allows for the transformation of quark flavors.
Quark-Quark Scattering:
Input Particles: Quarks from colliding protons or other high-energy particles.
Forces: Strong nuclear force mediated by gluons.
Output Particles: Quarks with different flavor compositions, including strange quarks.
Strangeness Creation: Quark-quark scattering processes, facilitated by the exchange of gluons, can lead to changes in quark flavors. These interactions may result in the creation of strange quarks in the final-state particles.
Let's explore specific examples of processes that lead to the creation of strange quarks :
Kaon Decay
B-meson decay
D-meson decay
Lambda decay
Hyperon Production:
Psi-decay
Figure 127 - Kaon K0 decay resulting in K-0
Figure 128 - B-meson decay creating Strange Quarks
Figure 129 - Strange Quark creation during long distance contribution to D0- 0
Figure 130 - Lambda decay with Strange Quark creation
Figure 131 - Hyperon Production (p -> Σ⁺ baryon)
Figure 132 - Psi (ψ) decay creating Strange Quark
Decay processes with strange quarks
Kaon Decay (K⁺ and K⁻)
Kaons (K⁺ and K⁻) are mesons that contain a strange quark. They predominantly decay via the weak interaction.
Lambda Baryon Decay (Λ)
The Lambda baryon (Λ) contains a strange quark and can decay via the weak interaction. Common decay modes for the Lambda baryon include:
Proton Decay: Λ can decay into a proton (p), a pi meson (π⁰), and other particles.
Sigma Baryon Decay (Σ):
Sigma baryons, such as Σ⁺, Σ⁰, and Σ⁻, contain strange quarks and can also undergo weak decays. Some possible decay modes include:
Pion Decay: Sigma baryons can decay into pions (π mesons) and other particles through weak interactions.
Xi Baryon Decay (Ξ):
Xi baryons (Ξ⁺, Ξ⁰, and Ξ⁻) contain strange quarks and can decay through weak interactions. Common decay modes include the production of pions and other hadrons.
Omega-minus Baryon Decay (Ω⁻):
The Omega-minus baryon (Ω⁻) contains three strange quarks and decays via the weak interaction. Typical decay modes include the production of pions and other hadrons.
Hyperon Decay:
Hyperons, which include Lambda (Λ), Sigma (Σ), Xi (Ξ), and Omega-minus (Ω⁻) baryons, can decay via weak interactions, leading to the production of various mesons and other hadrons.
Figure 133 - Kaon Decay (KL)
Figure 134 – Lamda (Λ0) decay with decay of a Strange Quark
Figure 135 – Sigma (Σ⁺) decay into pion (π⁰) with Strange Quark decay
Figure 136 - Omega minus (Ω⁻) decay
Annihilation processes where strange quarks are involved
Annihilation processes involving strange quarks occur when a particle and its corresponding antiparticle, both of which contain strange quarks, come into contact and annihilate each other, converting their mass into energy. These processes are fundamental in particle physics and play a crucial role in understanding the behavior of strange quarks and other quarks in the subatomic world. Here's a description of annihilation processes involving strange quarks:
Meson Annihilation:
Mesons are composite particles made up of a quark and an antiquark. Some mesons contain strange quarks (s) and strange antiquarks (s̄). When a meson with a strange quark meets its corresponding meson with a strange antiquark, they can annihilate.
For example, a K⁺ meson (containing a strange quark) can annihilate with a K⁻ meson (containing a strange antiquark), resulting in the conversion of their masses into energy. This process is governed by the principles of conservation of energy and conservation of quantum numbers.
Hyperon-antihyperon Annihilation:
Hyperons are baryons (hadrons composed of three quarks) that contain strange quarks. Antihyperons are their corresponding antiparticles, containing strange antiquarks.
When a hyperon and an antihyperon come into contact, they can annihilate, leading to the conversion of their rest mass into energy.
For example, a Lambda (Λ) hyperon (uds) can annihilate with an antilambda (Λ̄) antihyperon (ūd̄s̄), resulting in annihilation.
Strange Quark Matter Annihilation:
In extreme conditions, such as those believed to exist in the cores of neutron stars, strange quarks can combine to form strange quark matter, which is a hypothetical state of matter composed almost entirely of strange quarks.
If strange quark matter encounters its corresponding antimatter counterpart, the annihilation process can occur, releasing a tremendous amount of energy. This hypothetical process is believed to be responsible for the release of energy in certain astrophysical phenomena, such as gamma-ray bursts.
Quark-gluon Plasma (QGP) Annihilation:
In ultra-high-energy collisions at particle accelerators, such as the Large Hadron Collider (LHC), heavy-ion collisions can create a state known as quark-gluon plasma (QGP), where quarks and gluons exist as free particles.
Within the QGP, strange quarks and their antiquarks can encounter each other and annihilate, releasing energy. The study of strange quark annihilation within the QGP helps researchers understand the behavior of quarks under extreme conditions.
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