Universe\u2019s expansion<\/a> accelerate.<\/p>\nAround a year ago, the XENON1T experiment described an unanticipated signal, or excess, over the expected background.<\/p>\n
\u201cThese sorts of excesses are often flukes, but, once in a while, they can also lead to fundamental discoveries,\u201d commented Dr Luca Visinelli, a researcher at Frascati National Laboratories in Italy, a co-author of the study. \u201cWe explored a model in which this signal could be attributable to dark energy, rather than the dark matter the experiment was originally devised to detect.\u201d<\/p>\n
When these surprising results were first observed, the most widely accepted explanation for the excess were axions \u2013 hypothetical, extremely light particles \u2013 created in the Sun. However, this explanation does not corroborate with the observations, as the amount of axions that would be needed to explain the XENON1T signal would significantly modify the evolution of stars much heavier than the Sun, conflicting what was observed.<\/p>\n
The fifth force<\/h3>\n Currently, we have a lot to learn about what exactly dark energy is, however the majority of physical models for dark energy lead to the existence of a \u2018fifth force\u2019. There are four fundamental forces in the Universe, and any phenomena that cannot be clarified by one of these forces is often referred to as the result of an unknown fifth force.<\/p>\n
However, we understand that Einstein\u2019s theory of gravity works extremely well in the local universe. Therefore, any fifth force connected to dark energy is undesirable and must be \u2018hidden\u2019 or \u2018screened\u2019 when it comes to small scales, and can only operate on the largest scales where Einstein’s theory of gravity is incapable of explaining the acceleration of the Universe. To hide the fifth force, many models for dark energy are equipped with so-called screening mechanisms, which dynamically hide the fifth force.<\/p>\n
Chameleon screening<\/h3>\n For this experiment, the researchers assembled a physical model that utilised a sort of screening mechanism called \u2018chameleon screening\u2019, in order to demonstrate that dark energy particles produced in the Sun\u2019s strong magnetic fields could explain the XENON1T excess.<\/p>\n
\u201cOur chameleon screening shuts down the production of dark energy particles in very dense objects, avoiding the problems faced by solar axions,\u201d added Vagnozzi. \u201cIt also allows us to decouple what happens in the local very dense Universe from what happens on the largest scales, where the density is extremely low.\u201d<\/p>\n
The researchers applied their model to demonstrate what would occur in the detector if the dark energy was created in a specific region of the Sun, known as the tachocline, where the magnetic fields are particularly strong.<\/p>\n
\u201cIt was really surprising that this excess could in principle have been caused by dark energy rather than dark matter,\u201d said Vagnozzi. \u201cWhen things click together like that, it\u2019s really special.\u201d<\/p>\n
Their findings indicate that experiments such as XENON1T, which are intended to detect dark matter, could also be utilised to detect dark energy. However, the original excess must be convincingly confirmed.<\/p>\n
\u201cWe first need to know that this wasn\u2019t simply a fluke,\u201d concluded Visinelli. \u201cIf XENON1T actually saw something, you\u2019d expect to see a similar excess again in future experiments, but this time with a much stronger signal.\u201d<\/p>\n
If the excess was the consequence of dark energy, forthcoming upgrades to the XENON1T experiment, and experiments following similar objectives such as LUX-Zeplin and PandaX-xT, mean that it could be possible to directly detect dark energy within the next decade.<\/p>\n","protected":false},"excerpt":{"rendered":"
Researchers have determined the possibility that dark energy \u2013 the mysterious force that causes the Universe to accelerate \u2013 has been detected.<\/p>\n","protected":false},"author":13,"featured_media":14632,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[766,24429],"tags":[821],"acf":[],"yoast_head":"\n
Groundbreaking steps towards the direct detection of dark energy<\/title>\n \n \n \n \n \n \n \n \n \n \n \n \n \n\t \n\t \n\t \n \n \n \n \n \n\t \n\t \n\t \n