{"product_id":"thetarch-pixel-hoodie","title":"Thetarch – The Θ⁺(1540) Pentaquark Pixel Hoodie","description":"\u003cp\u003eThetarch, a pretender-king in tarnished violet plate, wears a crown of five jewels, four warm and one cold, whose linking thread is snapping.\u003c\/p\u003e\u003ch3\u003eThe Physics\u003c\/h3\u003e\u003cp\u003eIn 2003 the LEPS collaboration at SPring-8 reported a narrow peak near 1540 MeV in the K⁺n system, read as an exotic five-quark baryon, the Θ⁺, with minimal content uudd s̄. Its positive strangeness could not be made from three quarks, which is what made it exotic. Several other groups quickly reported sightings, but higher-statistics searches found nothing, and the Particle Data Group’s 2008 review judged the case that the Θ⁺ does not exist to be compelling, describing the whole story as a curious episode in the history of science.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eΘ⁺ = u u d d s̄:   Q = +1,  B = +1,  S = +1\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eu, d: up and down quarks, charges +2\/3 e and −1\/3 e\u003c\/li\u003e\n\u003cli\u003es̄: strange antiquark, charge +1\/3 e, strangeness +1\u003c\/li\u003e\n\u003cli\u003eQ: electric charge in units of e\u003c\/li\u003e\n\u003cli\u003eB: baryon number (each quark +1\/3, antiquark −1\/3)\u003c\/li\u003e\n\u003cli\u003eS: strangeness\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eOrdinary baryons qqq cannot have S = +1, so a narrow K⁺n resonance would have been unambiguous. The early peaks came from small samples and background modelling. Sources: T. Nakano et al. (LEPS), \u003cem\u003ePhys. Rev. Lett.\u003c\/em\u003e 91, 012002 (2003); C. Amsler et al. (PDG), “Pentaquark update”, \u003cem\u003ePhys. Lett. B\u003c\/em\u003e 667, 1 (2008).\u003c\/p\u003e\u003cp\u003e\u003cem\u003eHonest caveat:\u003c\/em\u003e Only this pentaquark is a ghost. Hidden-charm pentaquarks of a different kind were observed by LHCb in 2015. The 1540 MeV mass is approximate (about 1.53 to 1.54 GeV in early reports).\u003c\/p\u003e\u003ch3\u003eIn character\u003c\/h3\u003e\u003cp\u003e\u003cem\u003eFive jewels, they said, and a throne of my own. But the thread would not hold under more light, and the crown was only ever borrowed.\u003c\/em\u003e\u003c\/p\u003e\u003ch3\u003eOn the hoodie\u003c\/h3\u003e\u003cp\u003eFront: a five-jewel ring with one jewel hollow. Back: Thetarch in full pixel art with “BORN 2003 - DIED 2008” and “FIVE QUARKS, ZERO PARTICLE.” Gildan 18500 Heavy Blend hoodie, Black, S to 5XL.\u003c\/p\u003e\u003cp\u003ePart of the \u003cstrong\u003eGhost Particles That Were Wrong\u003c\/strong\u003e set with \u003ca href=\"\/id\/products\/sir-aetheron-pixel-hoodie\"\u003eSir Aetheron\u003c\/a\u003e, \u003ca href=\"\/id\/products\/enrayne-pixel-hoodie\"\u003eEnrayne\u003c\/a\u003e, \u003ca href=\"\/id\/products\/calorus-pixel-hoodie\"\u003eCalorus\u003c\/a\u003e, \u003ca href=\"\/id\/products\/diphantom-pixel-hoodie\"\u003eDiphantom\u003c\/a\u003e, \u003ca href=\"\/id\/products\/prematura-pixel-hoodie\"\u003ePrematura\u003c\/a\u003e. Browse all \u003ca href=\"\/id\/collections\/hoodies\"\u003ephysics hoodies\u003c\/a\u003e, more \u003ca href=\"\/id\/collections\/particle-physics\"\u003eparticle \u0026amp; nuclear physics designs\u003c\/a\u003e, or the \u003ca href=\"\/id\/collections\/deep-cuts\"\u003eDeep Cuts\u003c\/a\u003e.\u003c\/p\u003e","brand":"Printify","offers":[{"title":"Black \/ S","offer_id":50964469055591,"sku":"15472995321786188732","price":64.99,"currency_code":"USD","in_stock":true},{"title":"Black \/ M","offer_id":50964469088359,"sku":"24802921168101708604","price":64.99,"currency_code":"USD","in_stock":true},{"title":"Black \/ L","offer_id":50964469121127,"sku":"13900074891296054172","price":64.99,"currency_code":"USD","in_stock":true},{"title":"Black \/ XL","offer_id":50964469153895,"sku":"31893557861827652449","price":64.99,"currency_code":"USD","in_stock":true},{"title":"Black \/ 2XL","offer_id":50964469186663,"sku":"20591729413732960410","price":64.99,"currency_code":"USD","in_stock":true},{"title":"Black \/ 3XL","offer_id":50964469219431,"sku":"25440209351725703863","price":64.99,"currency_code":"USD","in_stock":true},{"title":"Black \/ 4XL","offer_id":50964469252199,"sku":"15793698387747725447","price":64.99,"currency_code":"USD","in_stock":true},{"title":"Black \/ 5XL","offer_id":50964469284967,"sku":"24907106921285903727","price":64.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/8746\/9159\/files\/03_H13_31727e01-b77b-45fe-8abb-bc407d8ef051.png?v=1793678467","url":"https:\/\/pixelatedphysics.com\/id\/products\/thetarch-pixel-hoodie","provider":"Pixelated Physics","version":"1.0","type":"link"}