08-29-2016, 10:02 PM
Dark matter is a new type of particle, one that interacts very weakly with all the known forces of the universe and is mostly only detectable via the gravitational pull it exerts. However, what kind of particle dark matter consists of remains unknown.
There are two known types of particles in the universe, fermions and bosons. Fermions include particles such as protons, neutrons and electrons, while bosons include particles such as the photons that make up the universe.
One of the fundamental challenges of researching dark matter is our inability to detect it. While it constitutes an estimated 27% of all the estimated mass and energy in the observable universe, it doesn’t interact with any type of electromagnetic radiation. Scientists have worked for decades to try and find direct evidence of dark matter’s existence, but to little avail. After its last, 20-month run, the Large Underground Xenon at Zeplin (LUX-Zeplin) dark matter experiment team reported that they had failed to detect any of the particles they were looking for.
But with the emergence of forces manipulated by the human mind, all we know about theoretical physics has changed.
A fifth fundamental force, perhaps discovered as part of the search for dark matter, has been reported in a new paper published in Physical Review Letters by senior author Danika Zayed. The results still need further analysis, but they represent a step forward for an idea that has caused several months of controversy in open-source journals, and which is potentially momentous enough that it’s making physicists’ imaginations run wild. Interactions across the universe are supposed to be governed by gravitation, electromagnetism, and the strong and weak nuclear forces; so what’s this about a fifth force?
The group of physicists led by Zayed went looking for something called the “dark photon,” which is a theorized carrier of the electromagnetic force for dark matter — we know dark matter doesn’t emit regular photons, but maybe it emits its own version. The team started looking in certain radioactive decay products by firing protons at thin targets of lithium-7, which created unstable beryllium-8 nuclei that quickly decayed. These decay products should produce electrons-positron pairs, and the Standard Model says that (for some reason) we should see fewer of these pairs as the electron and positron in each pair are emitted at a wider angle than expected.
This team found that there was an unusually large number of pairs with angles around 140º, creating a bump in their graph of pair-frequency versus emission angle. They quickly ruled out the possibility that this was being caused by decay of any known particle, and it clearly wasn’t a dark photon. So that left two possibilities: It was a mistake, or some totally new sort of particle. The team believes the bump corresponds to a previously unknown particle that’s being emitted from the unstable beryllium atoms and quickly decaying into an electron-positron pair with the observed angle of incidence. They found that this new particle should be about 30 times heavier than an electron, or about 17 MeV (megaelectronvolts).
Her original paper received little attention until a review by extraneous physicists. These scientists looked at the data and came to the conclusion that it didn’t contradict any known theory — meaning that while it is unknown, there’s also no reason to believe this new particle couldn’t exist. She claims that the particle is a boson, that it is not a mass-carrying particle, and that it doesn’t carry any of the four known forces. In principle, this implies that the particle is thus a force carrier for a force beyond the four currently known to exist.
This new force is odd. It interacts only over extremely short distances, a few atomic nuclei at most, and affects only electrons and neutrons. It’s being classified as a “protophobic X boson” where “protophobic” refers to the lack of interaction with protons, and the X literally means “unknown.” Most importantly, its energy level is low enough that it should be able to be created in a wide variety of labs around the world.
What might this mysterious new particle mean? Beyond blowing up the Standard Model, there’s hope that the newly discovered force might act as a bridge between the light and “dark” worlds. There’s no real indication of that, and it’s mostly wishful thinking. But the protophobic nature of the particle could be a key to the different interactions it would need to have with normal matter and dark matter, respectively. Such a dark force would be useful in revealing the nature of WIMPs (weakly interacting massive particles), the theorized mass-carrying particle that makes up dark matter. And it’s distinct from the dark photon, which would be the hypothetical electromagnetic force carrier for dark matter. The senior author intends to use their results in combination with techniques used to study gravitational waves to investigate the dark photon and dark wave, too, further advancing understanding of the material that makes up the majority of the mass in the universe.
There are two known types of particles in the universe, fermions and bosons. Fermions include particles such as protons, neutrons and electrons, while bosons include particles such as the photons that make up the universe.
One of the fundamental challenges of researching dark matter is our inability to detect it. While it constitutes an estimated 27% of all the estimated mass and energy in the observable universe, it doesn’t interact with any type of electromagnetic radiation. Scientists have worked for decades to try and find direct evidence of dark matter’s existence, but to little avail. After its last, 20-month run, the Large Underground Xenon at Zeplin (LUX-Zeplin) dark matter experiment team reported that they had failed to detect any of the particles they were looking for.
But with the emergence of forces manipulated by the human mind, all we know about theoretical physics has changed.
A fifth fundamental force, perhaps discovered as part of the search for dark matter, has been reported in a new paper published in Physical Review Letters by senior author Danika Zayed. The results still need further analysis, but they represent a step forward for an idea that has caused several months of controversy in open-source journals, and which is potentially momentous enough that it’s making physicists’ imaginations run wild. Interactions across the universe are supposed to be governed by gravitation, electromagnetism, and the strong and weak nuclear forces; so what’s this about a fifth force?
The group of physicists led by Zayed went looking for something called the “dark photon,” which is a theorized carrier of the electromagnetic force for dark matter — we know dark matter doesn’t emit regular photons, but maybe it emits its own version. The team started looking in certain radioactive decay products by firing protons at thin targets of lithium-7, which created unstable beryllium-8 nuclei that quickly decayed. These decay products should produce electrons-positron pairs, and the Standard Model says that (for some reason) we should see fewer of these pairs as the electron and positron in each pair are emitted at a wider angle than expected.
This team found that there was an unusually large number of pairs with angles around 140º, creating a bump in their graph of pair-frequency versus emission angle. They quickly ruled out the possibility that this was being caused by decay of any known particle, and it clearly wasn’t a dark photon. So that left two possibilities: It was a mistake, or some totally new sort of particle. The team believes the bump corresponds to a previously unknown particle that’s being emitted from the unstable beryllium atoms and quickly decaying into an electron-positron pair with the observed angle of incidence. They found that this new particle should be about 30 times heavier than an electron, or about 17 MeV (megaelectronvolts).
Her original paper received little attention until a review by extraneous physicists. These scientists looked at the data and came to the conclusion that it didn’t contradict any known theory — meaning that while it is unknown, there’s also no reason to believe this new particle couldn’t exist. She claims that the particle is a boson, that it is not a mass-carrying particle, and that it doesn’t carry any of the four known forces. In principle, this implies that the particle is thus a force carrier for a force beyond the four currently known to exist.
This new force is odd. It interacts only over extremely short distances, a few atomic nuclei at most, and affects only electrons and neutrons. It’s being classified as a “protophobic X boson” where “protophobic” refers to the lack of interaction with protons, and the X literally means “unknown.” Most importantly, its energy level is low enough that it should be able to be created in a wide variety of labs around the world.
What might this mysterious new particle mean? Beyond blowing up the Standard Model, there’s hope that the newly discovered force might act as a bridge between the light and “dark” worlds. There’s no real indication of that, and it’s mostly wishful thinking. But the protophobic nature of the particle could be a key to the different interactions it would need to have with normal matter and dark matter, respectively. Such a dark force would be useful in revealing the nature of WIMPs (weakly interacting massive particles), the theorized mass-carrying particle that makes up dark matter. And it’s distinct from the dark photon, which would be the hypothetical electromagnetic force carrier for dark matter. The senior author intends to use their results in combination with techniques used to study gravitational waves to investigate the dark photon and dark wave, too, further advancing understanding of the material that makes up the majority of the mass in the universe.