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Quark Configurations of New CERN LHC Hadrons
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 Quark Configurations of New CERN LHC HadronsHere’s a catchy rundown of the most exciting recent exotic hadrons discovered at CERN (mostly via LHCb)—with a focus on their quark configurations and why they’re pivotal: ⸻ 🧪 1. Strange Pentaquark: P⁽Λ⁾₍ψs₎(4338)⁰ • Quark content: c c̄ u d s — that’s one charm quark and its antiquark, plus up, down, and strange quarks  . • Why it matters: First-ever pentaquark to include a strange quark. A milestone in the exotic‑hadron “particle zoo” and a new window into how quarks bind together . ⚡ 2. Doubly Charged Open‑Charm Tetraquark: T₍cs0₎⁽²⁺⁺⁾(2900) • Quark content: c s̄ u d – charm, strange antiquark, up quark, down antiquark . • Sibling: Neutral partner T₍cs0₎⁽⁰⁾(2900) with content c s̄ d ū . • Why it matters: First observed tetraquark pair featuring both doubly charged and neutral isospin partners and involving open charm plus strange flavor . I asked the Android… I guess Google Gemini this same question, and I could have sworn it responded with a couple top quark hadrons, which se3n unlikely. It also noted unusual hadron half life measurements, but I did not delve into that. |
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Mesons, Baryons, Tetraquarks, Pentaquarks, Oh My! Baryons are three quark combinations, and must be all quarks or antiquarks. No miscegenation of a quark ménage a trois is permitted. Tetraquarks are four quark combinations, and pentaquarks are five quarks. Top quarks refuse to play (so far), and it is expected top quarks refuse existence is so fleeting they lack time to bond with other quarks. Charge parity (CP) violations occur with some hadron decays, shedding light (pun intended) on our universe. I watched a program last night on everything and nothing—my sister-in-law gave us Roku. Probably a mistake, but the program was fantastic, and very similar to another one I had watched earlier. The atmosphere. Luminiferous ether. Cepheid Variables, teased into revealing their secrets by Henrietta Leavitt who wasn’t permitted observatory access due to her gender. Edwin Hubble noted Cepheid Variable light in the Andromeda nebula, revealing that galaxy was far beyond our own beloved Milky Way, vastly expanding our understanding of our universe, the structure of which maps to quantum fluctuations very early in the Big Bang. I know some folks knock big bang cosmology, but they base their dismissal on political/religious ignorance and animosity of science. The Dali Lama once explained that where religious faith conflicts with scientific reality, those faith elements are best excised. Evolution makes no claim on God’s existence or non existence. Some insist we must reject the existence of God for “scientific” reasons, but I find that claim nonsensical. In the other hand, I also reject “God of the Gaps” arguments. Some things are mathematically and physically demonstrated to be unknowable. Gödel and Heisenberg Uncertainty comes unbidden. God’s existence appears to be in this category. To believe or not to believe, that is the question. Whether tis nobler in the minds of men flakes no skin off the nose of God. |
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What are unexpected or unusual half lives of hadrons? ⸻ 🧊 Unusually Long-Lived Hadrons These live far longer than typical hadrons (~10⁻²³ s), often due to suppressed or forbidden decay channels. 1. Neutron [udd] (free) – ~880 seconds • Why it’s odd: Inside nuclei, neutrons are [often] stable. But as free particles, they decay via weak interaction into a proton, electron, and antineutrino. • Suppression reason: Weak decay + phase space limitations. 2. Λ⁰ (Lambda nought baryon) – ~2.6 × 10⁻¹⁰ s • Why it’s unusual: Despite being a hadron with strong interaction capabilities, it decays via weak interaction (flavor change: strange → up). • Suppression reason: No strong decay path due to baryon number and flavor conservation. 3. K⁰_L (long-lived neutral kaon) – ~5.1 × 10⁻⁸ s • Why it’s weird: It’s a quantum superposition (K⁰ and anti-K⁰), with CP violation involved in its decay modes. • Suppression reason: Tiny CP-violating terms and weak decay. ⸻ ⚡ Unusually Short-Lived Hadrons Some hadrons decay faster than expected or are hard to measure due to their rapid decay into strong-interacting final states. 4. Δ⁺⁺ (Delta baryon) – ~6 × 10⁻²⁴ s • Why it’s special: Decays through strong interaction almost immediately into p + π⁺. • Typical hadron decay time: ~10⁻²³ s, but this is near the lower measurable bound. 5. ρ mesons (rho) – ~4.5 × 10⁻²⁴ s • Decay mode: Strong decay to two pions. • Why interesting: These mesons don’t live long enough to travel measurable distances—lifetimes inferred from decay width. ⸻ 🌀 Exotic and Unexpected Lifetimes These are due to complex mixing, suppression mechanisms, or rare decay channels. 6. B⁰_s meson – ~1.5 picoseconds • Strangeness: It undergoes flavor oscillation with its antiparticle, like kaons do, but on a different mass scale. • Fun twist: The oscillation frequency is faster than the decay rate. 7. X(3872) – ~not well-defined (width < 1.2 MeV → τ > 5 × 10⁻²³ s) • Why it’s strange: Possibly a tetraquark or D⁰-D̄*⁰ molecule. Narrow decay width suggests it’s unusually stable for an exotic hadron. • Suppression reason: Possibly small overlap between constituent mesons or decay phase-space limitations. 8. J/ψ (charmonium) – ~7.2 × 10⁻²¹ s • Why weird: A meson made of charm-anticharm quarks, but decays more slowly than expected because decays via strong interaction are forbidden — annihilation must occur. ⸻ 🎭 CP Violation and Lifetimes Kaon and B-meson systems show how symmetry violations affect decay: 9. K⁰_S vs K⁰_L • K⁰_S: ~9 × 10⁻¹¹ s • K⁰_L: ~5 × 10⁻⁸ s • Same quark content, different lifetimes because of quantum interference and CP-violating effects. 10. Neutral B-mesons (B⁰, B⁰_s) • Oscillations and CP violation lead to subtle differences in decay rates and are used to probe physics beyond the Standard Model. Summary Table Hadron Lifetime Decay Type Why It’s Unusual Neutron ~880 s Weak Stable in nuclei, but decays freely Λ⁰ 2.6 × 10⁻¹⁰ s Weak Strong decay forbidden K⁰_L 5.1 × 10⁻⁸ s Weak + CPV Long life due to CP violation Δ⁺⁺ 6 × 10⁻²⁴ s Strong Decays extremely fast ρ⁰ 4.5 × 10⁻²⁴ s Strong Broad width, short-lived B⁰_s ~1.5 ps Weak + mixing Fast flavor oscillations X(3872) >5 × 10⁻²³ s ? (weak/EM?) Possibly molecular, unusually narrow width J/ψ 7.2 × 10⁻²¹ s EM/annihilation Forbidden strong decay |
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Lambda Nought [uds] π− (negative pion, a meson) is made up of a down quark and anti up quark, so the charges are -2/3 and -1/3, summing to -1. This means the remaining particle (proton) must be positively charged. pasayten.org I must go fetch candy for my youngest grandson. |
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Oscillation Diagram The B⁰s meson is composed of a bottom antiquark and a strange quark and oscillates faster than it decays. I do not understand what is odd about this oscillation fact, and ponder if ChatGPT can satisfy my curiosity. |
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Big Bang Nucleosynthesis The short answer is: 👉 Heavier baryons were thermally suppressed due to their larger masses, and they decayed rapidly into nucleons once the universe cooled slightly. Let’s explore why nucleons dominate step by step. ⸻ 🧭 1. Thermal Equilibrium and Boltzmann Suppression 🔹 The early universe (~10⁻⁵–10⁻⁴ seconds after the Big Bang): • A hot, dense plasma of quarks, gluons, leptons, photons. • As it cooled below ΛQCD ~ 150–200 MeV, quarks and gluons “froze out” into hadrons: baryons (qqq) and mesons (q𝑞̄). 🔹 Relative abundance depends on the Boltzmann factor: n \propto g \cdot \exp\left(-\frac{m}{T}\right) Where: • n = number density • g = degrees of freedom (spin, isospin) • m = mass • T = temperature 🔹 Masses of common baryons: Baryon Mass (MeV) Proton 938 Neutron 940 Lambda (Λ) 1116 Sigma (Σ) ~1190 Xi (Ξ) ~1320 Omega (Ω) 1672 At T ≈ 150 MeV, you can already see: • m/T for a proton ≈ 6 • m/T for a Λ ≈ 7.4 • m/T for an Ω⁻ ≈ 11 So heavier baryons were exponentially less abundant. ⸻ 🧭 2. Decay of Heavy Baryons Even when they did form, heavier baryons like: • Λ → p + π⁻ or n + π⁰ (mean life: ~2.6×10⁻¹⁰ s) • Σ → N + π (lifetimes ~10⁻¹⁰ s) • Ξ → Λ + π (lifetimes ~10⁻¹⁰ s) decayed rapidly into nucleons + mesons. By the time nucleosynthesis started (t ≈ 1 s), the only stable baryons were: • Protons (stable) • Neutrons (t₁/₂ ≈ 10 min, but preserved in nuclei like He-4) ⸻ 🧭 3. Quark Content Bias Heavier baryons contain strange (s), charm (c), bottom (b), or even top (t) quarks. These: • Have higher mass, leading to greater suppression • Decay quickly to up/down quarks via weak interaction • Were essentially gone by the time baryon formation settled Only u and d quarks remained as stable matter — and they make up nucleons. Summary: At T ≈ 150 MeV, you can already see: • m/T for a proton ≈ 6 • m/T for a Λ ≈ 7.4 • m/T for an Ω⁻ ≈ 11 So heavier baryons were exponentially less abundant. ⸻ 🧭 2. Decay of Heavy Baryons Even when they did form, heavier baryons like: • Λ → p + π⁻ or n + π⁰ (mean life: ~2.6×10⁻¹⁰ s) • Σ → N + π (lifetimes ~10⁻¹⁰ s) • Ξ → Λ + π (lifetimes ~10⁻¹⁰ s) decayed rapidly into nucleons + mesons. By the time nucleosynthesis started (t ≈ 1 s), the only stable baryons were: • Protons (stable) • Neutrons (t₁/₂ ≈ 10 min, but preserved in nuclei like He-4) ⸻ 🧭 3. Quark Content Bias Heavier baryons contain strange (s), charm (c), bottom (b), or even top (t) quarks. These: • Have higher mass, leading to greater suppression • Decay quickly to up/down quarks via weak interaction • Were essentially gone by the time baryon formation settled Only u and d quarks remained as stable matter — and they make up nucleons. Only protons and neutrons survived because they were the lightest and most stable baryons — favored both statistically and dynamically.. Thank you for your attention to this matter. |
