#pentaquark

[ayumi-yoshioka]

月刊JICFuSムービーの音楽とサウンドを担当しました。 今回は、 スーパーコンピュータ「富岳」を用いてハドロンの研究をしている RIKENの杉浦拓也さんのインタビュー映像です。

［ムービークレジット］ 撮影地：理化学研究所（和光市） 音楽：吉岡亜由���「Inter」 演出・制作：南口雄一

「月刊JICFuS」は筑波大学計算科学研究センター、高エネルギー加速器研究機構、国立天文台の3組織が合同で立ち上げた研究組織「JICFuS（計算基礎科学連携拠点）」が発行しているwebマガジンです。

I was in charge of the music and sound for the monthly JICFuS movies. This time, it's an interview video with Takuya Sugiura from RIKEN, who is researching hadrons using the supercomputer "Fugaku."

[Movie Info] Location: Riken in Wako-city Music “Inter” by Ayumi Yoshioka  Directed by Yuichi Minamiguchi

“Monthly JICFuS” is a web magazine published by JICFuS (Joint Institute for Computational Fundamental Science), a research organisation jointly established by the University of Tsukuba’s Research Centre for Computational Science, the High Energy Accelerator Research Organisation and the National Astronomical Observatory of Japan.

[outletcrash]

chemists drive me irrationally crazy bc its so easy to work with electrons but QUARKS??? you can fuck around with how electrons bond by just wiggling it too hard. we have to throw OUR little fuckers like a bazillion mph into millions of OTHER little fuckers for them to do anything!. it would simply cost so much money to make my pentaquarks Maurice and double-up-double-down-anti-charm-Dave at home. i cant just buy a "splitting the atom kit" from walmart.

[marie-advanz]

Pentaquark EP de Obergman

[scienza-magia]

Stati della materia esotica costituiti da soli gluoni

Finalmente i fisici rilevano una nuova particella: le “Glueball”. Una nuova particella esotica, un gluone isolato, è stata scoperta dal gruppo di studio BES III e permette di comprendere meglio una delle forze fondamentali dell’universo. Secondo quanto pubblicato dalla rivista Physical Review Letters è stata scoperta una nuova particella fondamentale:  la “Glueball” cioè un gluone, particella dell’interazione nucleare forte, isolata e non combinata con nessuna altra particella. L’interazione nucleare forte è una delle quattro forze fondamentali dell’universo e il gluone è la sue espressione.

Queste particelle sono previste secondo il Modello Standard della fisica che, per quanto criticato e ancora con dei problemi, cerca di  essere la spiegazione a tutte le particelle esitenti. Sebbene la materia che ci costituisce sia composta da atomi, che sono costituiti da protoni, neutroni ed elettroni, e dove i protoni e i neutroni sono costituiti da tre quark ciascuno – tutti tenuti insieme da gluoni attraverso l’interazione forte – questo non è l’unica combinazione possibile di particelle, secondo il modello standard. Secondo il modello standard abbiamo: - barioni (con 3 quark ciascuno) o antibarioni (con 3 antiquark ciascuno). - mesoni (con una coppia quark-antiquark). - stati esotici come i tetraquark (2 quark e 2 antiquark), i pentaquark (4 quark e 1 antiquark o 1 quark e 4 antiquark), o gli esaquark (6 quark, 3 quark e 3 antiquark, o 6 antiquark), ecc. - oppure, si possono avere anche stati costituiti da soli gluoni – senza quark o antiquark di valenza – noti come glueball. In un nuovo documento radicale appena pubblicato sulla rivista Physical Review Letters, la collaborazione BES III ha appena annunciato che una particella esotica, precedentemente identificata come X(2370), potrebbe effettivamente essere la glueball più leggera prevista dal Modello Standard. Ecco la scienza dell’affermazione e il significato di tutto questo.

Tracce della camera a bolle di Fermilab, che rivelano la carica, la massa, l’energia e la quantità di moto delle particelle e delle antiparticelle create. Anche se possiamo ricostruire ciò che è accaduto nel punto di collisione per ogni singolo evento, abbiamo bisogno di un gran numero di statistiche per costruire prove sufficienti per affermare l’esistenza di una nuova specie di particelle. L’importanza della glueball sta nel fatto che è strettametne collegata con l’interazione nucleare forte, la forza che mantiene insieme i quarck nei protoni ed eletrroni e che poi tiene assieme i nuclei degli atomi. Si tratta dell’interazione più forte, 100 volte più forte di quella elettromagnerica. La scoperta della glueball, cioò di un singolo gluone, aiuterà a comprendere come funziona. Nel mondo della fisica delle alte energie, per trovare una particella non basta crearla in laboratorio e osservarla. Bisogna ripetere l’esperimento molte volte per verificare se le previsioni teoriche corrispondono ai risultati osservati. Questo è particolarmente importante quando si cercano particelle che esistono solo in condizioni rare. Molte particelle possono essere rilevate solo dalle firme lasciate quando altre particelle decadono. Nel corso del 20° secolo, sono state scoperte diverse particelle del Modello Standard, tra cui quark esotici come lo strano, il charm, il bottom e il top. Tutte le particelle contenenti questi quark sono instabili e decadono rapidamente. Per far esistere qualsiasi tipo di particella composita, devono essere seguite delle regole quantistiche. L’energia, la carica elettrica, il momento angolare e altre proprietà quantistiche devono essere conservate, ctanto per capirci che venga rispettata la legge per cui E=mc2. Read the full article

[elcitigre2021]

Linhas do Tempo Colpapsando...

As linhas de tempo podem ser conhecidas simplesmente como vibração atuante em determinadas faixas que afetam nossa vida e comportamento em uma dimensão paralela ou simultânea, em forma simples, podemos dizer que são fatos da nossa vida que aconteceram em determinadas datas neste e em outros “campos de realidades”.

Podemos considerar também que uma linha de tempo planetária tem a ver com eventos que afetam toda a humanidade. Quando diferentes linhas de tempo estão acontecendo simultaneamente estas terão que se agrupar e alinhar para que uma delas somente continue atuante. Atualmente na Terra estamos vivendo de uma forma quase incrível a interferência de essas linhas de tempo. Isto por causa da situação energética do planeta.

Muitos questionamentos deverão ser levantados para sustentar alguma coisa deste tipo, com nossos escassos conhecimentos acadêmicos, mesmo de física quântica. Os que estão mais perto de entender e compreender tudo isto de forma física e real são os cientistas que manipulam o acelerador de partícula (CERN) tentando encontrar a partícula de Deus como eles chamam.

O descobrimento do pentaquark parece trazer alguma luz em tudo isto, onde 4 quarks e um antiquarks se encontram, este anti quark estaria supostamente em um mundo paralelo simultâneo onde de certa forma estaria acontecendo o mesmo que aqui na Terra agora. Mas como que tudo isto encaixa então no “Efeito Mandela” (caso você não saiba do efeito Mandela, por favor, pesquise na internet e depois continue lendo esta postagem).

Temos que saber que estamos vivendo em varias dimensões quando estamos vivos na 3ª dimensão. Nosso corpo físico está na 3ª dimensão, nossa parte de consciência sempre vai estar uma dimensão acima. Desde a 3ª dimensão nosso corpo físico administra em conjunto com corpos de energia associados elementos ate a 12a dimensão, isto caso tivéssemos nosso DNA completo (12 fios ativados). Mesmo que nosso DNA não esteja totalmente ativado ainda, podemos “mexer” com estas dimensões, quando fazemos isto e existe um nível de consciência em isso, nos temos a capacidade de modificar linhas de tempo na Terra.

No ”Efeito Mandela” muitas pessoas lembram-se de coisas que não aconteceram aqui, mas que aconteceu em outra dimensão paralela. Ficou afinal, a melhor linha de tempo possível. Mas como você vai modificar uma linha de tempo? Mudando eventos, mudando direcionamento de projetos, tomando decisões diferentes referentes a coisas importantes da sua vida!! E como você vai saber de tudo isso? Primeiro, acreditando que existe um mundo invisível e que existe um ser divino, um Mestre que você É. Esse Mestre que você É poderá ter você ao tanto de tudo o que acontece nas outras linhas de tempo paralelas e levando você a tomar consciência da linha de tempo correta, mesmo que isso não aconteça 100% na consciência acordada. Tive provas claras do “efeito Mandela” na minha vida com pessoas amigas de toda a vida, em encontros recentes em Santiago de Chile, mesmo que elas não tenham consciência total de isso. Vamos continuar pesquisando, hoje a época do ciclo planetário onde muitas energias se encontram é um campo de exploração fantástico.

[unravelingwires]

Baryons

“You look… frustrated,” Shae commented.

“Do I?” Lakshmi snapped before sighing. “I—are you okay with being a rubber duck?”

She sat down. “What, exactly, does that entail?”

“A rubber duck is an engineer term. I explain the problem I’m having and hopefully the act of explaining it helps.”

“Sure.”

“So, I’ve been looking at the readings from the ring and comparing them to the readings from the space around us. The readings from around us are basically useless because we are in a void, and I have ridiculously few data points. The ring is weirder. Some of the molecules spit at us had protons heavier than protons are supposed to be. In one case, a wave of light was blue until it hit the receiver, at which point it turned green. The wavelength of light was green. Sensors picked up one pentaquark, which is a particle that has never been seen outside laboratory experiments.” Lakshmi sighed. “Maybe the sensors are glitching.”

“I talked to Dr. Whittemore, and he said the nuclei of the iron in the asteroid samples he picked up is slightly heavier than that in the ship. He doesn’t know what that means.”

Lakshmi froze before whirling to her console. “Wait. Wait, that’s—alright, give me one second, I need to—alright we know the wavelength and the distance so the time is easy, and if you consider what is being emitted when…”

“I’ll just get going, then,” Shae said, amused. Lakshmi apparently didn’t hear her, as she didn’t respond.

[quarkylife]

I watched a video by The Royal Institution on YouTube named "What are Pentaquarks and why are they so rare?" which was uploaded 3 years ago. And it was really good at simplifying quantum chromodynamics and what quarks are!! However, I struggled to understand some of the stuff about the data but I think I get some of it!! :D soooooo ill do my best to summarise it ((as if I can ever be concise lmao))

The main answer to the question posed by the title of the video was a solid we dont know what exactly Pentaquarks are and why they're soooo rare buuut scientists at the LHC are working on it!!

Quarks and leptons are the fundamental particles. Quarks in particular are always linked together by te strong nuclear force to form hadrons - you can't EVER find them singularly due to quark confinement ((energy needed to separate two quarks forms mass forming another quark)). However quarks are usually found in quark triplets or quark antiquark pairs!?!?!?! WHY!?!? It could be due to the quarks property colour charge limiting some possibilities. The colour charge is associated with the strong force ((force keeping quarks together)), similar to how the electric charge is linked to the electric force. It acts as a source for the force to act on. The three types of colour charge are : red, green and blue. All together make white. In hadrons, the colour charges cancel out / make white so overall the object is neutral and doesnt experience the strong force. So the only caviat here for other particles containing quarks is the colour charges need to cancel, so it's not really much of a reason why particles containing quarks other than quark triplets and quark-antiquark pairs are soooo rare.

Scientists have been working on this issue....aaannnddd in 2008 tetra quarks (4 quarks) were discovered!! Aaannnd in 2015....drumroll please!! Pentaquarks (5 quarks) were discovered!!! However, they're not stable so decay quickly so cant be directly observed. Thus scientists look for pentaquarks by finding the particles they decay into - psi mesons and protons. And the lack if knowledge we have on pentaquarks shows we really dont know a lot about the strong nuclear force (what forms them) as we dont even know if they're formed of the fusion of a meson and baryon or the fusion of five singular quarks......but yuh...they exist and it's a start!!

[wozziebear]

The international LHCb collaboration at the Large Hadron Collider (LHC) has observed three never-before-seen particles: a new kind of “pentaquark” and the first-ever pair of “tetraquarks”, which includes a new type of tetraquark. The findings, presented today at a CERN seminar, add three new exotic members to the growing list of new hadrons found at the LHC. They will help physicists better understand how quarks bind together into these composite particles.

Quarks are elementary particles and come in six flavours: up, down, charm, strange, top and bottom. They usually combine together in groups of twos and threes to form hadrons such as the protons and neutrons that make up atomic nuclei. More rarely, however, they can also combine into four-quark and five-quark particles, or “tetraquarks” and “pentaquarks”. These exotic hadrons were predicted by theorists at the same time as conventional hadrons, about six decades ago, but only relatively recently, in the past 20 years, have they been observed by LHCb and other experiments.

Most of the exotic hadrons discovered in the past two decades are tetraquarks or pentaquarks containing a charm quark and a charm antiquark, with the remaining two or three quarks being an up, down or strange quark or their antiquarks. But in the past two years, LHCb has discovered different kinds of exotic hadrons. Two years ago, the collaboration discovered a tetraquark made up of two charm quarks and two charm antiquarks, and two “open-charm” tetraquarks consisting of a charm antiquark, an up quark, a down quark and a strange antiquark. And last year it found the first-ever instance of a “double open-charm” tetraquark with two charm quarks and an up and a down antiquark. Open charm means that the particle contains a charm quark without an equivalent antiquark.

The discoveries announced today by the LHCb collaboration include new kinds of exotic hadrons. The first kind, observed in an analysis of “decays” of negatively charged B mesons, is a pentaquark made up of a charm quark and a charm antiquark and an up, a down and a strange quark. It is the first pentaquark found to contain a strange quark. The finding has a whopping statistical significance of 15 standard deviations, far beyond the 5 standard deviations that are required to claim the observation of a particle in particle physics.

The second kind is a doubly electrically charged tetraquark. It is an open-charm tetraquark composed of a charm quark, a strange antiquark, and an up quark and a down antiquark, and it was spotted together with its neutral counterpart in a joint analysis of decays of positively charged and neutral B mesons. The new tetraquarks, observed with a statistical significance of 6.5 (doubly charged particle) and 8 (neutral particle) standard deviations, represent the first time a pair of tetraquarks has been observed.

Large Hadron Collider discovers three new exotic particles

https://home.cern/news/news/physics/lhcb-discovers-three-new-exotic-particles Comments

[startswithabang]

Nuclear Physics Might Hold The Key To Cracking Open The Standard Model

“Interestingly, this could also lead to a renewed interest in the search for glueballs, which would be the first ever direct evidence of a bound state of gluons in nature! If the exotic QCD predictions of tetraquarks and pentaquarks are borne out in our Universe, it stands to reason that glueballs should be there as well. Perhaps the existence of these composite particles will be verified at the LHC as well, with incredible implications for how our Universe works either way.”

Nuclear physics has, for decades now, been regarded less as a window into fundamental physics and more of a derived science. As we’ve discovered that nuclei, baryons, and mesons are all composite particles made out of quarks, antiquarks, and gluons, though, we’ve realized that there are other possible combinations that nature allows, that should exist. In recent years, we’ve discovered tetraquark and pentaquark states of quarks and antiquarks, and yet there should be even more. QCD, our theory of the strong interactions, predicts that a set of exotic states of bound gluons -- known as a glueball -- should exist. Finding them, or proving that they don’t exist, might be a way to crack open the Standard Model in an entirely new way.

Nuclear physics might, after all these years, hold the key to going beyond the current limitations of physics.

[piotrekperezdesigner]

Welcome to Multiplatform Content!!

Recién llegado a la consultora de marketing digital, Multiplatform Content (MPC) en Madrid!. Muy ilusionado y contento de formar parte de este gran equipo humano multidisciplinar. Muchos retos y grandes proyectos están por llegar.  #Welovecontent

Multiplatform Content (MPC) es un grupo de Consultoría de marketing digital, centrado en la creación de contenidos y la gestión de datos. Ofrece un modelo de especialización vertical por sectores de conocimiento: Travel, Entertainment, Omnichannel y Governance. 

Cuenta con una estrategia que combina la captación de audiencias/clientes a través de contenidos -vídeo, posts, acciones publicitarias o comerciales- y la gestión de datos -modelos predictivos, CRM, motores de recomendación-. Clientes líderes como NH Hotel Group, Sony Pictures, Bankia o el ICO ya trabajan con este modelo de marketing. 

Dentro del grupo, la oferta de servicios se completa a través de diferentes partners: Wayland (marketing de influencers), Craft Media (compra programática) y Pentaquark (Data Science). MPC ya opera en mercados internacionales a través de sus oficinas de Madrid, Caracas, Ciudad de Panamá y Ciudad de México.

Fuente: http://www.multiplatformcontent.com/

[biographyiq]

[scienza-magia]

Nuova particella "esotica" scoperta al Cern di Ginevra

Cern, osservato un nuovo tipo di tetraquark. La scoperta della particella composta da quattro quark charm grazie alla collaborazione internazionale dell'esperimento LHCb che opera all'acceleratore LHC del Cern. Un nuovo tipo di tetraquark è stato osservato per la prima volta grazie alla collaborazione internazionale dell'esperimento LHCb che opera all'acceleratore LHC del Cern. La scoperta della particella composta da quattro quark charm è annunciata da uno studio su arXiv. Il risultato costituisce un importante passo avanti nella comprensione di come i quark si legano tramite interazioni nucleari forti all'interno di particelle composte, note come adroni, alla cui famiglia appartengono anche i protoni e i neutroni, costituenti dei nuclei atomici. Nei casi comuni, i quark si legano in coppie (mesoni) o tripletti (barioni), ma l'esistenza di particelle più complesse costituite da quattro quark (tetraquark), cinque quark (pentaquark) o più, non è, in linea di principio, proibita dalla teoria, sebbene siano stati necessari decenni di ricerche per poterne identificare pochi esempi. I quark già noti si legano in coppie (mesoni) o tripletti (barioni), ma l’esistenza di particelle più complesse costituite da quattro quark (tetraquark), cinque quark (pentaquark) o più non è esclusa dalla teoria, anche se ci sono voluti decenni di ricerche per poterne identificare pochi esempi. Read the full article

[spaceexp]

LHCb discovers a new type of tetraquark at CERN

CERN - European Organization for Nuclear Research logo. July 1, 2020 The LHCb collaboration has observed an exotic particle made up of four charm quarks for the first time.

Image above: Illustration of a tetraquark composed of two charm quarks and two charm antiquarks, detected for the first time by the LHCb collaboration at CERN. (Image: CERN). The LHCb collaboration has observed a type of four-quark particle never seen before. The discovery, presented at a recent seminar at CERN and described in a paper posted today on the arXiv preprint server, is likely to be the first of a previously undiscovered class of particles. The finding will help physicists better understand the complex ways in which quarks bind themselves together into composite particles such as the ubiquitous protons and neutrons that are found inside atomic nuclei. Quarks typically combine together in groups of twos and threes to form particles called hadrons. For decades, however, theorists have predicted the existence of four-quark and five-quark hadrons, which are sometimes described as tetraquarks and pentaquarks, and in recent years experiments including the LHCb have confirmed the existence of several of these exotic hadrons. These particles made of unusual combinations of quarks are an ideal “laboratory” for studying one of the four known fundamental forces of nature, the strong interaction that binds protons, neutrons and the atomic nuclei that make up matter. Detailed knowledge of the strong interaction is also essential for determining whether new, unexpected processes are a sign of new physics or just standard physics. “Particles made up of four quarks are already exotic, and the one we have just discovered is the first to be made up of four heavy quarks of the same type, specifically two charm quarks and two charm antiquarks,” says the outgoing spokesperson of the LHCb collaboration, Giovanni Passaleva. “Up until now, the LHCb and other experiments had only observed tetraquarks with two heavy quarks at most and none with more than two quarks of the same type.” “These exotic heavy particles provide extreme and yet theoretically fairly simple cases with which to test models that can then be used to explain the nature of ordinary matter particles, like protons or neutrons. It is therefore very exciting to see them appear in collisions at the LHC for the first time,” explains the incoming LHCb spokesperson, Chris Parkes. The LHCb team found the new tetraquark using the particle-hunting technique of looking for an excess of collision events, known as a “bump”, over a smooth background of events. Sifting through the full LHCb datasets from the first and second runs of the Large Hadron Collider, which took place from 2009 to 2013 and from 2015 to 2018 respectively, the researchers detected a bump in the mass distribution of a pair of J/ψ particles, which consist of a charm quark and a charm antiquark. The bump has a statistical significance of more than five standard deviations, the usual threshold for claiming the discovery of a new particle, and it corresponds to a mass at which particles composed of four charm quarks are predicted to exist.

Large Hadron Collider (LHC). Animation Credit: NASA

As with previous tetraquark discoveries, it is not completely clear whether the new particle is a “true tetraquark”, that is, a system of four quarks tightly bound together, or a pair of two-quark particles weakly bound in a molecule-like structure. Either way, the new tetraquark will help theorists test models of quantum chromodynamics, the theory of the strong interaction. Read more on the LHCb website: https://lhcb-public.web.cern.ch/Welcome.html#Tcccc Note: CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature. The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions. Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 23 Member States. Related links: CERN paper: https://arxiv.org/abs/2006.16957 Large Hadron Collider (LHC): https://home.cern/science/accelerators/large-hadron-collider LHCb experiment: https://lhcb-public.web.cern.ch/lhcb-public/Welcome.html For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/ Image (mentioned), Animation (mentioned), Text, Credits: European Organization for Nuclear Research (CERN). Best regards, Orbiter.ch Full article

[sciencespies]

Physicists just found 4 new subatomic particles that may test the laws of nature

https://sciencespies.com/physics/physicists-just-found-4-new-subatomic-particles-that-may-test-the-laws-of-nature/

Physicists just found 4 new subatomic particles that may test the laws of nature

This month is a time to celebrate. CERN has just announced the discovery of four brand new particles at the Large Hadron Collider (LHC) in Geneva.

This means that the LHC has now found a total of 59 new particles, in addition to the Nobel prize-winning Higgs boson, since it started colliding protons – particles that make up the atomic nucleus along with neutrons – in 2009.

Excitingly, while some of these new particles were expected based on our established theories, some were altogether more surprising.

The LHC’s goal is to explore the structure of matter at the shortest distances and highest energies ever probed in the lab – testing our current best theory of nature: the Standard Model of Particle Physics. And the LHC has delivered the goods – it enabled scientists to discover the Higgs boson, the last missing piece of the model. That said, the theory is still far from being fully understood.

One of its most troublesome features is its description of the strong force which holds the atomic nucleus together. The nucleus is made up of protons and neutrons, which are in turn each composed of three tiny particles called quarks (there are six different kinds of quarks: up, down, charm, strange, top and bottom).

If we switched the strong force off for a second, all matter would immediately disintegrate into a soup of loose quarks – a state that existed for a fleeting instant at the beginning of the universe.

Don’t get us wrong: the theory of the strong interaction, pretentiously called “quantum chromodynamics“, is on very solid footing. It describes how quarks interact through the strong force by exchanging particles called gluons. You can think of gluons as analogues of the more familiar photon, the particle of light and carrier of the electromagnetic force.

However, the way gluons interact with quarks makes the strong force behave very differently from electromagnetism. While the electromagnetic force gets weaker as you pull two charged particles apart, the strong force actually gets stronger as you pull two quarks apart.

As a result, quarks are forever locked up inside particles called hadrons – particles made of two or more quarks – which includes protons and neutrons. Unless, of course, you smash them open at incredible speeds, as we are doing at Cern.

To complicate matters further, all the particles in the standard model have antiparticles which are nearly identical to themselves but with the opposite charge (or other quantum property). If you pull a quark out of a proton, the force will eventually be strong enough to create a quark-antiquark pair, with the newly created quark going into the proton.

You end up with a proton and a brand new “meson”, a particle made of a quark and an antiquark. This may sound weird but according to quantum mechanics, which rules the universe on the smallest of scales, particles can pop out of empty space.

This has been shown repeatedly by experiments – we have never seen a lone quark. An unpleasant feature of the theory of the strong force is that calculations of what would be a simple process in electromagnetism can end up being impossibly complicated. We therefore cannot (yet) prove theoretically that quarks can’t exist on their own.

Worse still, we can’t even calculate which combinations of quarks would be viable in nature and which would not.

Illustration of a tetraquark. (CERN)

When quarks were first discovered, scientists realized that several combinations should be possible in theory. This included pairs of quarks and antiquarks (mesons); three quarks (baryons); three antiquarks (antibaryons); two quarks and two antiquarks (tetraquarks); and four quarks and one antiquark (pentaquarks) – as long as the number of quarks minus antiquarks in each combination was a multiple of three.

For a long time, only baryons and mesons were seen in experiments. But in 2003, the Belle experiment in Japan discovered a particle that didn’t fit in anywhere. It turned out to be the first of a long series of tetraquarks.

In 2015, the LHCb experiment at the LHC discovered two pentaquarks.

The four new particles we’ve discovered recently are all tetraquarks with a charm quark pair and two other quarks. All these objects are particles in the same way as the proton and the neutron are particles. But they are not fundamental particles: quarks and electrons are the true building blocks of matter.

Is a pentaquark tightly (above) or weakly bound (see image below)? (CERN)

Charming new particles

The LHC has now discovered 59 new hadrons. These include the tetraquarks most recently discovered, but also new mesons and baryons. All these new particles contain heavy quarks such as “charm” and “bottom”.

These hadrons are interesting to study. They tell us what nature considers acceptable as a bound combination of quarks, even if only for very short times.

They also tell us what nature does not like. For example, why do all tetra- and pentaquarks contain a charm-quark pair (with just one exception)? And why are there no corresponding particles with strange-quark pairs? There is currently no explanation.

Is a pentaquark a molecule? A meson (left) interacting with a proton (right). (CERN)

Another mystery is how these particles are bound together by the strong force. One school of theorists considers them to be compact objects, like the proton or the neutron.

Others claim they are akin to “molecules” formed by two loosely bound hadrons. Each newly found hadron allows experiments to measure its mass and other properties, which tell us something about how the strong force behaves. This helps bridge the gap between experiment and theory. The more hadrons we can find, the better we can tune the models to the experimental facts.

These models are crucial to achieve the ultimate goal of the LHC: find physics beyond the standard model. Despite its successes, the standard model is certainly not the last word in the understanding of particles. It is for instance inconsistent with cosmological models describing the formation of the universe.

The LHC is searching for new fundamental particles that could explain these discrepancies. These particles could be visible at the LHC, but hidden in the background of particle interactions. Or they could show up as small quantum mechanical effects in known processes.

In either case, a better understanding of the strong force is needed to find them. With each new hadron, we improve our knowledge of nature’s laws, leading us to a better description of the most fundamental properties of matter.

Patrick Koppenburg, Research Fellow in Particle Physics, Dutch National Institute for Subatomic Physics and Harry Cliff, Particle physicist, University of Cambridge.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

#Physics