paper<\/a> in the Journal of High Energy Physics, scientists including physicists at MIT report that sPHENIX precisely measured the number and energy of particles that streamed out from gold ions that collided at close to the speed of light.<\/p>\nStraight ahead<\/p>\n
This test is considered in physics to be a \u201cstandard candle,\u201d meaning that the measurement is a well-established constant that can be used to gauge a detector\u2019s precision.<\/p>\n
In particular, sPHENIX successfully measured the number of charged particles that are produced when two gold ions collide, and determined how this number changes when the ions collide head-on, versus just glancing by. The detector\u2019s measurements revealed that head-on collisions produced 10 times more charged particles, which were also 10 times more energetic, compared to less straight-on collisions.<\/p>\n
\u201cThis indicates the detector works as it should,\u201d says Gunther Roland, professor of physics at MIT, who is a member and former spokesperson for the sPHENIX Collaboration. \u201cIt\u2019s as if you sent a new telescope up in space after you\u2019ve spent 10 years building it, and it snaps the first picture. It\u2019s not necessarily a picture of something completely new, but it proves that it\u2019s now ready to start doing new science.\u201d<\/p>\n
\u201cWith this strong foundation, sPHENIX is well-positioned to advance the study of the quark-gluon plasma with greater precision and improved resolution,\u201d adds Hao-Ren Jheng, a graduate student in physics at MIT and a lead co-author of the new paper. \u201cProbing the evolution, structure, and properties of the QGP will help us reconstruct the conditions of the early universe.\u201d<\/p>\n
The paper\u2019s co-authors are all members of the sPHENIX Collaboration, which comprises over 300 scientists from multiple institutions around the world, including Roland, Jheng, and physicists at MIT\u2019s Bates Research and Engineering Center.<\/p>\n
\u201cGone in an instant\u201d<\/p>\n
Particle colliders such as Brookhaven\u2019s RHIC are designed to accelerate particles at \u201crelativistic\u201d speeds, meaning close to the speed of light. When these particles are flung around in opposite, circulating beams and brought back together, any smash-ups that occur can release an enormous amount of energy. In the right conditions, this energy can very briefly exist in the form of quark-gluon plasma \u2014 the same stuff that sprung out of the Big Bang.<\/p>\n
Just as in the early universe, quark-gluon plasma doesn\u2019t hang around for very long in particle colliders. If and when QGP is produced, it exists for just 10 to the minus 22, or about a sextillionth, of a second. In this moment, quark-gluon plasma is incredibly hot, up to several trillion degrees Celsius, and behaves as a \u201cperfect fluid,\u201d moving as one entity rather than as a collection of random particles. Almost immediately, this exotic behavior disappears, and the plasma cools and transitions into more ordinary particles such as protons and neutrons, which stream out from the main collision.<\/p>\n
\u201cYou never see the QGP itself \u2014 you just see its ashes, so to speak, in the form of the particles that come from its decay,\u201d Roland says. \u201cWith sPHENIX, we want to measure these particles to reconstruct the properties of the QGP, which is essentially gone in an instant.\u201d<\/p>\n
\u201cOne in a billion\u201d<\/p>\n
The sPHENIX detector is the next generation of Brookhaven\u2019s original\u00a0Pioneering High Energy Nuclear Interaction eXperiment, or PHENIX, which measured collisions of heavy ions generated by RHIC. In 2021, sPHENIX was installed in place of its predecessor, as a faster and more powerful version, designed to detect quark-gluon plasma\u2019s more subtle and ephemeral signatures.<\/p>\n
The detector itself is about the size of a two-story house and weighs around 1,000 tons. It sits at the intersection of RHIC\u2019s two main collider beams, where relativistic particles, accelerated from opposite directions, meet and collide, producing particles that fly out into the detector. The sPHENIX detector is able to catch and measure 15,000 particle collisions per second, thanks to its novel, layered components, including the MVTX, or micro-vertex \u2014 a subdetector that was designed, built, and installed by scientists at MIT\u2019s Bates Research and Engineering Center.<\/p>\n
Together, the detector\u2019s systems enable sPHENIX to act as a giant 3D camera that can track the number, energy, and paths of individual particles during an explosion of particles generated by a single collision.<\/p>\n
\u201cSPHENIX takes advantage of developments in detector technology since RHIC switched on 25 years ago, to collect data at the fastest possible rate,\u201d\u00a0says MIT postdoc Cameron Dean, who was a main contributor to the new study\u2019s analysis. \u201cThis allows us to probe incredibly rare processes for the first time.\u201d<\/p>\n
In the fall of 2024, scientists ran the detector through the \u201cstandard candle\u201d test to gauge its speed and precision. Over three weeks, they gathered data from sPHENIX as the main collider accelerated and smashed together beams of gold ions traveling at the speed of light. Their analysis of the data showed that sPHENIX accurately measured the number of charged particles produced in individual gold ion collisions, as well as the particles\u2019 energies. What\u2019s more, the detector was sensitive to a collision\u2019s \u201chead-on-ness,\u201d and could observe that head-on collisions produced more particles with greater energy, compared to less direct collisions.<\/p>\n
\u201cThis measurement provides clear evidence that the detector is functioning as intended,\u201d Jheng says.<\/p>\n
\u201cThe fun for sPHENIX is just beginning,\u201d Dean adds. \u201cWe are currently back colliding particles and expect to do so for several more months. With all our data, we can look for the one-in-a-billion rare process that could give us insights on things like the density of QGP, the diffusion of particles through ultra-dense matter, and how much energy it takes to bind different particles together.\u201d<\/p>\n
This work was supported, in part, by\u00a0the U.S.\u00a0Department of Energy Office of Science, and the National Science Foundation.<\/p>\n","protected":false},"excerpt":{"rendered":"A new and powerful particle detector just passed a critical test in its goal to decipher the ingredients…\n","protected":false},"author":2,"featured_media":135095,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[49],"tags":[84855,84854,44060,84851,84852,84850,199,84856,79,84853],"class_list":{"0":"post-135094","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-standard-candle-test","9":"tag-bates-research-and-engineering-center","10":"tag-early-universe","11":"tag-gunther-roland","12":"tag-hao-ren-jheng","13":"tag-mit-laboratory-for-nuclear-science","14":"tag-physics","15":"tag-relativistic-heavy-ion-collider","16":"tag-science","17":"tag-sphenix"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/135094","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=135094"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/135094\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/135095"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=135094"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=135094"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=135094"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}