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发帖数: 6104 | 1 不会是假的吧
Irvine, Calif., August 15, 2016 – Recent findings indicating the possible
discovery of a previously unknown subatomic particle may be evidence of a
fifth fundamental force of nature, according to a paper published in the
journal Physical Review Letters by theoretical physicists at the University
of California, Irvine.
“If true, it’s revolutionary,” said Jonathan Feng, professor of physics &
astronomy. “For decades, we’ve known of four fundamental forces:
gravitation, electromagnetism, and the strong and weak nuclear forces. If
confirmed by further experiments, this discovery of a possible fifth force
would completely change our understanding of the universe, with consequences
for the unification of forces and dark matter.”
The UCI researchers came upon a mid-2015 study by experimental nuclear
physicists at the Hungarian Academy of Sciences who were searching for “
dark photons,” particles that would signify unseen dark matter, which
physicists say makes up about 85 percent of the universe’s mass. The
Hungarians’ work uncovered a radioactive decay anomaly that points to the
existence of a light particle just 30 times heavier than an electron.
“The experimentalists weren’t able to claim that it was a new force,”
Feng said. “They simply saw an excess of events that indicated a new
particle, but it was not clear to them whether it was a matter particle or a
force-carrying particle.”
The UCI group studied the Hungarian researchers’ data as well as all other
previous experiments in this area and showed that the evidence strongly
disfavors both matter particles and dark photons. They proposed a new theory
, however, that synthesizes all existing data and determined that the
discovery could indicate a fifth fundamental force. Their initial analysis
was published in late April on the public arXiv online server, and a follow-
up paper amplifying the conclusions of the first work was released Friday on
the same website.
The UCI work demonstrates that instead of being a dark photon, the particle
may be a “protophobic X boson.” While the normal electric force acts on
electrons and protons, this newfound boson interacts only with electrons and
neutrons – and at an extremely limited range. Analysis co-author Timothy
Tait, professor of physics & astronomy, said, “There’s no other boson that
we’ve observed that has this same characteristic. Sometimes we also just
call it the ‘X boson,’ where ‘X’ means unknown.”
Feng noted that further experiments are crucial. “The particle is not very
heavy, and laboratories have had the energies required to make it since the
’50s and ’60s,” he said. “But the reason it’s been hard to find is that
its interactions are very feeble. That said, because the new particle is so
light, there are many experimental groups working in small labs around the
world that can follow up the initial claims, now that they know where to
look.”
Like many scientific breakthroughs, this one opens entirely new fields of
inquiry.
One direction that intrigues Feng is the possibility that this potential
fifth force might be joined to the electromagnetic and strong and weak
nuclear forces as “manifestations of one grander, more fundamental force.”
Citing physicists’ understanding of the standard model, Feng speculated
that there may also be a separate dark sector with its own matter and forces
. “It’s possible that these two sectors talk to each other and interact
with one another through somewhat veiled but fundamental interactions,” he
said. “This dark sector force may manifest itself as this protophobic force
we’re seeing as a result of the Hungarian experiment. In a broader sense,
it fits in with our original research to understand the nature of dark
matter.” |
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